Journal articles on the topic 'Sea urchins'
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1
Karnila, R., D. Iriani, S. Md Shaarani, A. A. Yunus, and R. Salma. "Nutritional characteristics of sea urchin (Diadema setosum) in Bungus, West Sumatera Province." IOP Conference Series: Earth and Environmental Science 1118, no. 1 (December 1, 2022): 012037. http://dx.doi.org/10.1088/1755-1315/1118/1/012037.
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Abstract Sea urchin is a food that has high nutrition for consumption and sale. Utilization of the gonad Diadema setosum as a food ingredient because it has high nutritional value, such as food additives, fermented products, and body health. Sea urchin gonad components consist of amino acids that are beneficial in various fields of health, especially in increasing the immune system. This study aims to obtain the value of the proportion and chemical composition of sea urchins gonad. The research method consisted of two stages, namely: 1) Preparation of sea urchin gonadal flour and 2) Proximate analysis of sea urchins gonad. Parameters observed consisted of morphology, proportion of sea urchins, and proximate sea urchins. The results showed that 7 cm diameter sea urchins had a proportion value of 11.11% shell and 4.44% gonad. The chemical composition of sea urchins gonad is moisture content 74.54%, ash content 17.44% (db), protein content 58.96% (db), fat content 20.31% (db), and carbohydrates 3.30% (db).
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Yu, Yushi, Jiangnan Sun, Yaqing Chang, and Chong Zhao. "High fitness areas drive the aggregation of the sea urchin Mesocentrotus nudus." PeerJ 10 (January 19, 2022): e12820. http://dx.doi.org/10.7717/peerj.12820.
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Sea urchin aggregation is a common phenomenon in coastlines. However, it remains controversial whether sea urchins form resource aggregations or behavioral aggregations in a non-spawning season. To clarify, we studied the aggregative responses to food and predators in the sea urchin Mesocentrotus nudus when high fitness areas (HFAs) were scarce versus sufficient. By taking the occupied area of each sea urchin (test diameter + spines = 4.5 cm) as a square (4.5 cm × 4.5 cm), we set scarce HFAs for the sea urchins in Experiment 1 (the squares of HFAs: the area occupied by experimental sea urchins = 1:1) and sufficient HFAs for the sea urchins in Experiment 2 (the squares of HFAs: the area occupied by experimental sea urchins = 2:1). If M. nudus form resource aggregations, they would aggregate passively under the scarce HFAs conditions, but not in the sufficient HFAs conditions. Conversely, if M. nudus form behavioral aggregation, aggregation would occur in both scarce and sufficient HFAs. The present results showed that in the scarce HFAs, M. nudus in the food and predator groups were significantly closer to the food and further from predators, and had significantly more aggregated numbers in HFAs than those in the control group. Sea urchins did not aggregate in response to food or predators under the sufficient HFAs, although significantly more sea urchins of the experimental group was found in HFAs than that of the control group. Sea urchins (at least M. nudus) form resource aggregations that are driven by the scarce HFAs. This provides valuable information into the mechanisms of the aggregation of sea urchins.
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Tamti, Hartati, Rohani Ambo-Rappe, Sharifuddin Bin Andy Omar, Budimawan Pagalay, Muhammad Iqram, and Abigail Mary Moore. "Sea urchin utilisation in Eastern Indonesia." ILMU KELAUTAN: Indonesian Journal of Marine Sciences 28, no. 3 (August 8, 2023): 231–40. http://dx.doi.org/10.14710/ik.ijms.28.3.231-240.
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Sea urchins have long been an important component of gleaning invertebrate fisheries and are valued for their highly nutritious gonads. Sea urchin fisheries are often unreported and unregulated, despite increasing indications of overexploitation. Data on the post-harvest utilization of sea urchins are limited, particularly in the Indo-Pacific region. This study at 12 sites across four regions in Indonesia (Sulawesi, Moluccas, Nusa Tenggara, Papua) aimed to provide an overview of sea urchin utilization in eastern Indonesia. Data were collected from July to September 2020 using a questionnaire with a snowballing sampling method. There were 187 respondents (62.6% male and 37.4% female) ranged in age from 3-76 years old, and most had been collecting sea urchins for more than five years. Respondents mostly collected the sea urchins from coral reef or seagrass habitats. Four genera (Tripneustes, Diadema, Echinometra and Echinothrix) were identified. Mean catch ranged from 32 (Makassar) to 169 (Maluku Tengah) individual sea urchin per collection. Most respondents knew local names for sea urchins, especially those they collected. Almost 70% respondents used their catch mainly for home consumption, and only 4.8% respondents mainly selling their catch. Most urchins sold were whole or crudely de-spined, typically fetching IDR 500-1000 each. Additional post-harvest processing before sale included removing the gonads from the test and/or cooking, with a unit price of IDR 5,000-25,000/product. Commonly consumed raw, urchins were sometimes cooked (mostly barbecued). These data indicate a need for efforts towards socio-ecologically appropriate sea urchin conservation and fisheries management to address the widespread indications of increasing exploitation levels and declining sea urchin populations.
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Smith, Joshua G., and Sabrina C. Garcia. "Variation in purple sea urchin (Strongylocentrotus purpuratus) morphological traits in relation to resource availability." PeerJ 9 (April 27, 2021): e11352. http://dx.doi.org/10.7717/peerj.11352.
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Flexible resource investment is a risk sensitive reproductive strategy where individuals trade resources spent on reproduction for basic metabolic maintenance and survival. This study examined morphological variation in herbivorous sea urchin grazers across a mosaic landscape of macroalgae dominated habitats interspersed with patches of sea urchin barrens to determine whether sea urchins shift energy allocation in response to food limitation. Extensive underwater surveys of habitat attributes (e.g., sea urchin density, algae cover) were paired with detailed laboratory assays (e.g., sea urchin dissections) to determine how resource abundance affects energy allocation between reproductive capacity and body structure in the purple sea urchin, Strongylocentrotus purpuratus. We found that: (1) sea urchins had a more elongate jaw structure relative to body size in habitats void of macroalgae (i.e., barrens), (2) sea urchin reproductive capacity (i.e., gonad index) was lower in barrens and the barrens habitat was primarily comprised of encrusting algae, and (3) sea urchin jaw morphology (i.e., lantern index) and reproductive capacity (i.e., gonad index) were inversely related. These results suggest that sea urchins respond to macroalgae limited environments by shifting energy allocation between reproductive capacity and modifications of the foraging apparatus, which may explain the ability of sea urchins to acquire food in resource-limited environments.
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Rossetto, André Luiz, Jamesson de Macedo Mora, and Vidal Haddad Junior. "Sea urchin granuloma." Revista do Instituto de Medicina Tropical de São Paulo 48, no. 5 (October 2006): 303–6. http://dx.doi.org/10.1590/s0036-46652006000500013.
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Injuries caused by venomous and poisonous aquatic animals may provoke important morbidity in humans. The phylum Echinoderma include more than 6000 species of starfish, sea urchins, sand dollars, and sea cucumbers some of which have been found responsible for injuries to humans. Initial injuries by sea urchins are associated with trauma and envenomation, but later effects can be observed. Sea urchin granuloma is a chronic granulomatous skin disease caused by frequent and successive penetration of sea urchin spines which have not been removed from wounds. The authors report a typical case of sea urchin granuloma in a fisherman and its therapeutic implications.
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Kadir, Wiyanti Abd, Sri Nuryatin Hamzah, and La Nane. "The abundance and distribution patterns of sea urchins in Botubarani waters, Tomini Bay, Indonesia." Tomini Journal of Aquatic Science 2, no. 1 (July 27, 2021): 14–23. http://dx.doi.org/10.37905/tjas.v2i1.11237.
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This study aims to determine the abundance and distribution patterns of sea urchins in Botubarani Waters, Kabila Bone District, Bone Bolango Regency. This research was conducted from July to August 2020. A total of three research stations were established, namely West Tamboa, Central Tamboa and East Tamboa. The abundance of sea urchins was calculated using a quadrant transect measuring 1 × 1 m, which was laid 25 m perpendicular to the coastline using a line transect. Sea urchin species found were identified in situ and the distribution pattern of sea urchins was calculated using the morista dispersion index. The results showed that there were 5 types of sea urchins in Botubarani Beach, namely Echinometra mathaei, Diadema setosum, Echinotrix calamaris, Echinotrix diadema and Tripneustes gratilla. The sea urchin type Echinometra mathaei is the species with the highest abundance in all research stations, namely 25 ind./m2 at Tamboa Barat station, 9 ind./m2 at Tamboa Tengah station and 7 ind./m2 at Tamboa Timur station. The distribution patterns of sea urchins found in Botubarani waters include clusters for Echinometra mathaei and uniform patterns for sea urchins Diadema setosum, Echinotrix calamaris, Echinotrix diadema and Tripneustes gratilla. ANOVA analysis results show that there is no significant difference between sea urchin abundance and water quality parameters in all research stations. This indicates that there is no difference in environmental conditions at the three sampling locations.
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Tian, Wenzhuo, Zhong Wang, Xiaofei Leng, Peng Liu, Hao Guo, Xuechun Jiang, Fanjiang Ou, et al. "Comparison of Immune Indicators Related to Phagocytosis of Five Species of Sea Urchins under Artificial Infection with the Pathogenic Bacterium of Black Mouth Disease." Biology 13, no. 7 (July 3, 2024): 495. http://dx.doi.org/10.3390/biology13070495.
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To screen for immune indicators closely related to disease resistance, two species of sea urchin susceptible to black mouth disease (Strongylocentrotus intermedius, S. intermedius ♀ × Heliocidaris crassispina ♂) and three species of sea urchin resistant to black mouth disease (H. crassispina, H. crassispina ♀ × S. intermedius ♂ and Mesocentrotus nudus) were artificially infected with the black mouth pathogen Vibrio echinoideorum. The phagocytosis-related immune indices of the five sea urchin species were compared at different time points post-infection. The results demonstrated that the parameters such as apoptotic rate of phagocytes, mean contribution value (MCV) of single effective phagocyte on Acid Phosphatase (ACP), Reactive Oxygen Species (ROS), and Total Antioxidant Capacity (T-AOC) of the five sea urchin species first increased and then decreased after infection. The key time points were 3 h to 6 h and 48 h post-infection when the black mouth disease-resistant and susceptible sea urchins demonstrated differences. At 3 h or 6 h post-infection, the up-regulation folds in MCV of ACP, ROS and T-AOC of black mouth disease-resistant sea urchins were considerably higher than that of the susceptible sea urchins. At 6 h post-infection, the apoptosis rate and the phagocytic index (PI) of the black mouth disease-resistant sea urchins were significantly higher than those of the susceptible sea urchins (p < 0.05). At 48 h post-infection, the necrosis rate of phagocytes, MCV of ACP and MCV of ROS of the black mouth disease-resistant sea urchins were significantly lower than those of the susceptible sea urchins (p < 0.05). The apoptosis and necrosis rate of phagocytes, PI, and MCV on ACP, ROS may be used as indicators of disease resistance in sea urchins. Disease resistance standards in immune indices can be summarized as phagocytosis increases greatly in the early infection stage and decreases timely to a normal level after killing the pathogen in a short period.
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Snellen, C. L., P. J. Hodum, and E. Fernández-Juricic. "Assessing western gull predation on purple sea urchins in the rocky intertidal using optimal foraging theory." Canadian Journal of Zoology 85, no. 2 (February 2007): 221–31. http://dx.doi.org/10.1139/z06-203.
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Purple sea urchins ( Strongylocentrotus purpuratus (Stimpson, 1857)) are abundant grazing invertebrates that can have a major impact on the rocky intertidal community. Predators can control the urchin population and indirectly reduce grazing activity. We determined the effects of western gull ( Larus occidentalis Audubon, 1839) predation on purple sea urchins in the rocky intertidal using the framework of optimal foraging theory and taking into account different prey-handling techniques. We recorded the foraging behavior of gulls, measured urchin availability, and estimated prey caloric content with bomb calorimetry. Western gulls selected purple sea urchins significantly more than other prey items (snails (genus Tegula Lesson, 1835), limpets (genus Collisella Dall, 1871), sea stars ( Pisaster giganteus (Stimpson, 1857) and Pisaster ochraceus (Brandt, 1835))). Larger urchins contained relatively more calories. Gulls foraged optimally when pecking by frequently selecting the most profitable size class. However, gulls chose smaller urchins than expected when air-dropping, which could have been influenced by group size and age. Gulls selected smaller purple sea urchins when foraging in larger groups likely owing to the risk of kleptoparasitism. Adults chose larger, and juveniles smaller, urchins when air-dropping, suggesting that juveniles are less experienced in foraging techniques. We estimated that gull predation could affect up to one third of the sea urchin populations locally, which could increase species diversity in the rocky intertidal community.
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CVITKOVIĆ, IVAN, MARIJA DESPALATOVIĆ, ANTE ŽULJEVIĆ, IVAN VUČIĆ, PETRA LUČIĆ, and JELENA NEJAŠMIĆ. "Distribution of sea urchin barrens in shallow algal communities along the eastern Adriatic coast." Mediterranean Marine Science 25, no. 1 (April 22, 2024): 213–19. http://dx.doi.org/10.12681/mms.33553.
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The sea urchins Paracentrotus lividus and Arbacia lixula are important herbivores in algal communities of the infralittoral rocky bottoms in the Mediterranean Sea. However, grazing by sea urchins that outweighs natural algal recruitment processes might result in the formation of barrens, which are areas dominated by urchins and coralline algae. We present the results of the first large-scale mapping of sea urchin barrens and analyses of sea urchins’ impact on the main algal communities across 1955.5 km of rocky coastline on the eastern side of the Adriatic Sea (Croatia). Since mapping was performed over a geographically wide area and covered a representative quantity of approximately 40% of the coastline of the central part of the Adriatic Sea, the results could be considered to reflect the general situation in that area of the eastern Adriatic coast. Mapping revealed that sea urchin barrens are present along over 35% of the coastline, while the complete absence of algal cover was recorded in 8% of the inspected area. Communities with canopy-forming algae, which are the most valuable shallow-water communities of the Mediterranean Sea, represent the largest proportion of the observed coastline and are affected by sea urchins in over 28% of their extent. Among other factors, the extensive harvesting of date mussels (Lithophaga lithophaga) in the 1970s, 1980s, and early 1990s is likely one of the main activities that resulted in exceptional sea urchin expansion via the removal of micropredators and establishment of shelters for subadult urchins.
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Morse, Bryan L., and Heather L. Hunt. "Effect of unidirectional water currents on displacement behaviour of the green sea urchin Strongylocentrous droebachiensis." Journal of the Marine Biological Association of the United Kingdom 93, no. 7 (May 29, 2013): 1923–28. http://dx.doi.org/10.1017/s002531541300060x.
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Sea urchins can have important ecological effects on benthic communities through their aggregation and feeding behaviour. Urchin movement has been demonstrated to be negatively affected by wave action, but the impact of unidirectional tidal currents on urchin movement has not been investigated. This study examines the effect of unidirectional water velocity on the direction of displacement and movement rate of the green sea urchin, Strongylocentrotus droebachiensis. In laboratory flume experiments there was a clear effect of water currents on the displacement of sea urchins. At speeds ≤30 cm s−1 urchins moved across the current in a downstream direction, but at speeds of ≥36 cm s−1 the urchins switched directions by more than 90° and moved across the current in an upstream direction. There was a significant effect of flow speed on urchin movement speed, with urchin movement speed decreasing as water current speed increased.
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Pederson, Hugh G., and Craig R. Johnson. "Growth and age structure of sea urchins (Heliocidaris erythrogramma) in complex barrens and native macroalgal beds in eastern Tasmania." ICES Journal of Marine Science 65, no. 1 (November 20, 2007): 1–11. http://dx.doi.org/10.1093/icesjms/fsm168.
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Abstract Pederson, H. G., and Johnson, C. R. 2008. Growth and age structure of sea urchins (Heliocidaris erythrogramma) in complex barrens and native macroalgal beds in eastern Tasmania. – ICES Journal of Marine Science, 65: 1–11. The formation of small-scale barrens of sea urchins on the east coast of Tasmania allows for direct comparison of the growth rates and age structures of sea urchin populations in barrens and habitats dominated by native macroalgae. However, such barrens are atypical of any previously described in temperate regions worldwide mainly because of the establishment and seasonal colonization by the introduced macroalga Undaria pinnatifida. Growth models were fitted to sea urchin (Heliocidaris erythrogramma) data, based on tag-recapture information from two distinct community types, a native macroalgal bed and a sea urchin barren colonized by U. pinnatifida. Despite the distinct contrast in habitats, size-at-age relationships and age frequency distributions were not significantly different between the two populations. However, the relationship between jaw length and test diameters was significantly different between populations, sea urchins in barrens possessing larger jaws relative to conspecifics of similar test diameter in native macroalgal habitats. It is proposed that the growth of sea urchins on barrens is not adversely affected by the loss of native macroalgae in the presence of U. pinnatifida. However, sea urchins display a level of resource limitation in barrens because of differences in the relationships of sea urchin morphometrics.
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Roem, Muhamad, Retno Setianingrum, and Encik Weliyadi. "ASSOCIATION BETWEEN ECHINOID AND SEAGRASS COMMUNITY IN DERAWAN ISLAND WATERS." Journal of Aquatropica Asia 7, no. 2 (December 1, 2022): 104–16. http://dx.doi.org/10.33019/joaa.v7i2.3608.
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Sea urchins a biota that is often associated with seagrasses were often found in seagrass beds. The objectives of this research were to discover the condition of sea urchins and seagrass, such as diversity, uniformity, dominance in sea urchins, density, and cover on seagrass, and related to variables in this research. This research was conducted on Derawan Island. The research method that was used is a 5m x 5m (sea urchin) quadrate and 0.5m x 0.5m (seagrass) placed intentionally on 2 stations with a total of 30 quadrats. The results found 3 species of sea urchins and 4 species of seagrass. At station 1 abundance of sea urchins is 2.94 individual/m2 whereas at station 2 is 0,28 individual/m2. At station 1 seagrass density 117,33 shoot/m2 whereas station 2 is 120,13 shoot/m2. Seagrass cover at station 1 is 58,75% and at station 2 is 60,28%. The dominant sea urchin species is Diadema setosum with the following diversity values H'=0,36, E=0,3, and C=0.81. There was no significant difference between variables at each station except temperature (0.020<0.05) and DO (0.027<0.05). Variables that were correlated with sea urchins in the seagrass ecosystem are nitrate, salinity, phosphate, temperature, and pH. The association with seagrasses in Derawan Island is positive.
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Sabilu, Yusuf, Jafriati, and Ruslan Madjid. "TEST OF BIOACTITVITY AND ANTIOXIDANT ACTIVITY OF SEA URCHIN (DIADEMA SETOSUM) GONADS AS MEDICINAL INGREDIENTS BASED ON MARINE BIODIVERSITY." Journal of Southwest Jiaotong University 57, no. 1 (February 28, 2022): 147–53. http://dx.doi.org/10.35741/issn.0258-2724.57.1.13.
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Sea urchins (Diadema setosum) are marine animals belonging to phylum Echinodermata which are often found in the Wakatobi's waters. Although Indonesia is one of the exporters of sea urchins, the use of sea urchins as medicinal and health food products has not been widely used. This is due to the limited information about the potential active compounds contained in sea urchins from Indonesian waters. This study aimed to determine the bioactivity and antioxidant activity of gonad extract of sea urchin (Diadema setosum). The sample test consisted of several stages, namely extraction by maceration using 96% ethanol solvent, phytochemical test and antioxidant activity testing. The results showed that the ethanol extract of the gonads of sea urchin (Diadema setosum) contained alkaloids, steroids, triterpenoids and tannins. The results of the antioxidant activity test of the ethanol extract of the gonads of sea urchin (Diadema setosum) showed that the extract had no potential as an antioxidant because it had IC50 value of > 250 ppm. The IC50 value was 4460.1505 ppm. The novelty of this study resulted in data of bioactive compounds and antioxidant activity of sea urchin gonads Diadema setosum that are useful for different herbal formulations as anti-tumour, anti-cancer, anti-inflammatory, analgesic, anti-fatigue, anti-Parkinson effect, and anti-hypoglycemic.
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Moningkey, Ruddy D. "PERAN EKOLOGI BULU BABI DALAM KOMUNITAS RUMPUT LAUT DI PERAIRAN PESISIR KEMA KABUPATEN MINAHASA UTARA." JURNAL PERIKANAN DAN KELAUTAN TROPIS 7, no. 1 (April 15, 2011): 1. http://dx.doi.org/10.35800/jpkt.7.1.2011.18.
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A study on the functional role of the sea urchin, Salmacis belli, on seagrass bed near the coast of Kema, North Minahasa Regency, was done by analyzing the gut contents, the food preference, and the feeding periodicity. Sea urchins and plants were collected from the seagrass bed by snorkeling along a 100 M transect line with 30 quadrates randomly placed. The feeding periodicity was determined from the gut index in 24 hours with 3 hour intervals. The results showed that the sea urchin S. belli fed mainly on seagrass Thallasia hemprichii, Enhalus acoroides and Halimeda opuntioa. The feeding periodicity data indicated that the sea urchins actively fed in the day. The grazing capacity of the sea urchin was not affected by their body size. In high density, sea urchins could potentially cause negative impact on the seagrass bed (i.e., destruction of the meadow).
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Spyksma, AJP, NT Shears, and RB Taylor. "Injured conspecifics as an alarm cue for the sea urchin Evechinus chloroticus." Marine Ecology Progress Series 641 (May 7, 2020): 135–44. http://dx.doi.org/10.3354/meps13301.
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Predator mediation of sea urchin grazing pressure may occur via lethal removal of individual sea urchins or non-lethal modification of sea urchin behaviour. Several studies have shown that predation-related cues can affect sea urchin movement and grazing rates, but generalisations about the types of cues that prompt responses and the magnitude of those responses will require further research on a wider variety of species. We examined the effects of potential alarm cues on behaviour of the habitat-forming sea urchin Evechinus chloroticus (Echinometridae) on fished rocky reefs in northeastern New Zealand, where predators are uncommon and the sea urchins form barrens. Exposed E. chloroticus (i.e. those not in crevices) rapidly fled from injured conspecifics within a 1 m radius of the cue, but showed no apparent reaction to injured sea urchins belonging to another family (Centrostephanus rodgersii, Diadematidae), diced pilchards or the disturbance caused by fish attracted to the cues. Densities of exposed sea urchins in an area containing injured conspecifics did not return to control values for at least 20 h, while cryptic individuals remained crevice-bound when injured conspecifics were nearby. Injured conspecifics thus provide a strong, albeit localised, cue for E. chloroticus. By restricting sea urchins to crevices where they have a reduced impact on living kelp, this non-consumptive effect may complement the lethal effects of predation in marine reserves where populations of predators such as rock lobsters and large fish are allowed to recover from overharvesting by humans, thereby reinforcing the trophic cascade initiated by those predators.
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Sonnenholzner, Jorge, Gema Alcivar, Adrián Marquez, and César Lodeiros. "Los erizos Arbacia incisa y Eucidaris thouarsii (Echinodermata) como agentes de biocontrol del “fouling” en canastas de cultivo de Crassostrea gigas (Mollusca: Ostreidae)." Revista de Biología Tropical 65, no. 1-1 (December 8, 2017): 35. http://dx.doi.org/10.15517/rbt.v65i1-1.31665.
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The sea urchins Arbacia incisa and Eucidaris thouarsii (Echinodermata) as fouling biocontrol agents in culture cages of Crassostrea gigas (Mollusca: Ostreidae).Fouling clogs cultivation cages of bivalves afecting their growth. We tested biocontrol with sea urchins in the suspended culture of C. gigas during one month. The experimental design included: 1) oysters without sea urchins, 2) oysters with the black sea urchin Arbacia incisa (50.5 ± 0.43 mm of diameter testa-DT), 3) oysters with the pencil sea urchin E. thouarsii (34. 2 ± 2.13 mm DT) and 4) oysters without sea urchins with a pearl net protective bag (to avoid predation). The dry mass of the pearl nets and the oyster soft tissues were determined at the beginning and end of the experiment. There was similar fouling in cages without urchins (55.3 ± 5.80 g) and with A. incisa (46.1 ± 2.84 g). These amounts were significantly higher than those found in cages with E. thouarsii (39.1 ± 1.9 g) and with protective sacs without urchins (35.6 ± 5.17 g). The growth of C. gigas with E. thouarsii was significantly higher (0.49 ± 0.089 g). We recommend E. thouarsii as a fouling biocontrol agent for C. gigas. Rev. Biol. Trop. 65(Suppl. 1): S35-S41. Epub 2017 November 01.
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Amir, Yam, Maayan Insler, Abram Giller, Danielle Gutman, and Gil Atzmon. "Senescence and Longevity of Sea Urchins." Genes 11, no. 5 (May 20, 2020): 573. http://dx.doi.org/10.3390/genes11050573.
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Sea urchins are a minor class of marine invertebrates that share genetic similarities with humans. For example, the sea urchin species Strongylocentrotus purpuratus is estimated to have 23,300 genes in which the majority of vertebrate gene families are enveloped. Some of the sea urchin species can demonstrate extreme longevity, such as Mesocentrotus franciscanus, living for well over 100 years. Comparing human to sea urchin aging suggests that the latter do not fit within the classic understanding of biological aging, as both long- and short-lived sea urchin species demonstrate negligible senescence. Sea urchins are highly regenerative organisms. Adults can regenerate external appendages and can maintain their regenerative abilities throughout life. They grow indeterminately and reproduce throughout their entire adult life. Both long- and short-lived species do not exhibit age-associated telomere shortening and display telomerase activity in somatic tissues regardless of age. Aging S. purpuratus urchins show changes in expression patterns of protein coding genes that are involved in several fundamental cellular functions such as the ubiquitin-proteasome system, signaling pathways, translational regulation, and electron transport chain. Sea urchin longevity and senescence research is a new and promising field that holds promise for the understanding of aging in vertebrates and can increase our understanding of human longevity and of healthy aging.
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Farina, Simone, Maura Baroli, Roberto Brundu, Alessandro Conforti, Andrea Cucco, Giovanni De Falco, Ivan Guala, et al. "The challenge of managing the commercial harvesting of the sea urchin Paracentrotus lividus: advanced approaches are required." PeerJ 8 (October 8, 2020): e10093. http://dx.doi.org/10.7717/peerj.10093.
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Sea urchins act as a keystone herbivore in marine coastal ecosystems, regulating macrophyte density, which offers refuge for multiple species. In the Mediterranean Sea, both the sea urchin Paracentrotus lividus and fish preying on it are highly valuable target species for artisanal fisheries. As a consequence of the interactions between fish, sea urchins and macrophyte, fishing leads to trophic disorders with detrimental consequences for biodiversity and fisheries. In Sardinia (Western Mediterranean Sea), regulations for sea urchin harvesting have been in place since the mid 90s. However, given the important ecological role of P. lividus, the single-species fishery management may fail to take into account important ecosystem interactions. Hence, a deeper understanding of population dynamics, their dependance on environmental constraints and multispecies interactions may help to achieve long-term sustainable use of this resource. This work aims to highlight how sea urchin population structure varies spatially in relation to local environmental constraints and species interactions, with implications for their management. The study area (Sinis Peninsula, West Sardinia, Italy) that includes a Marine Reserve was divided into five sectors. These display combinations of the environmental constraints influencing sea urchin population dynamics, namely type of habitat (calcareous rock, granite, basalt, patchy and continuous meadows of Posidonia oceanica), average bottom current speed and predatory fish abundance. Size-frequency distribution of sea urchins under commercial size (<5 cm diameter size) assessed during the period from 2004 to 2007, before the population collapse in 2010, were compared for sectors and types of habitat. Specific correlations between recruits (0–1 cm diameter size) and bottom current speeds and between middle-sized sea urchins (2–5 cm diameter size) and predatory fish abundance were assessed. Parameters representing habitat spatial configuration (patch density, perimeter-to-area ratio, mean patch size, largest patch index, interspersion/juxtaposition index) were calculated and their influence on sea urchin density assessed. The density of sea urchins under commercial size was significantly higher in calcareous rock and was positively and significantly influenced by the density and average size of the rocky habitat patches. Recruits were significantly abundant in rocky habitats, while they were almost absent in P. oceanica meadows. The density of middle-sized sea urchins was more abundant in calcareous rock than in basalt, granite or P. oceanica. High densities of recruits resulted significantly correlated to low values of average bottom current speed, while a negative trend between the abundance of middle-sized sea urchins and predatory fish was found. Our results point out the need to account for the environmental constraints influencing local sea urchin density in fisheries management.
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Belleza, Dominic Franco C., Takeshi Urae, Shin-ichiro Tanimae, Kento Toyama, Akari Isoda, and Gregory N. Nishihara. "The behavior of sympatric sea urchin species across an ecosystem state gradient." PeerJ 11 (June 13, 2023): e15511. http://dx.doi.org/10.7717/peerj.15511.
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Background In temperate macroalgal forests, sea urchins are considered as a keystone species due to their grazing ability. Given their potential to shape benthic communities, we monitored the habitat use by three sympatric sea urchin species and compared their behaviors in a vegetated habitat (VH) and an adjacent isoyake habitat (IH). Methods We monitored the environmental conditions and sea urchin density along deep and shallow transects of the VH and IH for over a year. The benthic rugosity at both sites were also surveyed. A mark-recapture experiment was conducted on the two most abundant sea urchins, Diadema setosum and Heliocidaris crassispina, to elucidate sea urchin movement patterns and group dynamics. Results We found that exposure to waves was highest at the VH while the IH was sheltered. The deep IH experienced the least amount of light due to high turbidity. Water temperature patterns were similar across sites. The VH benthic topography was more rugose compared to the smoother and silt-covered IH substate. Peak macroalgal bloom occurred three months earlier in IH, but macroalgae persisted longer at the shallow VH. Among the sympatric sea urchins, H. crassispina was most abundant at the shallow VH and was observed in pits and crevices. The most abundant across IH and in the deep VH was D. setosum, preferring either crevices or free-living, depending on hydrodynamic conditions. The least abundant species was D. savignyi, and most often observed in crevices. Small and medium sea urchins were most often observed at the IH site, whereas larger sea urchins were more likely observed at the VH. The mark-recapture study showed that D. setosum was found to displace further at the IH, and H. crassispina was more sedentary. Additionally, D. setosum was always observed in groups, whereas H. crassispina was always solitary. Discussion The behaviors of sympatric urchins, Diadema savignyi, D. setosum and H. crassispina, differed in response to changes in the benthic environment and physical conditions. Sea urchin displacement increased when rugosity and wave action were low. Habitat preference shifted to crevices in seasons with high wave action. In general, the mark-recapture experiment showed that sea urchins displaced further at night.
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Adni, Nainul, Aras Mulyadi, and Thamrin Thamrin. "POPULATION CONDITIONS OF ECHINOIDEA AND CORAL REEF COVERS IN PONCAN GODANG ISLAND, SIBOLGA, NORTH SUMATERA." Asian Journal of Aquatic Sciences 4, no. 2 (August 23, 2021): 112–16. http://dx.doi.org/10.31258/ajoas.4.2.112-116.
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Poncan Godang Island is included in the appropriate category based on the suitability of land for the Sibolga tourist area, with the presence of tourism activities that can also affect the amount of biodiversity in it. Considering the importance of coral reefs for biodiversity and sea urchins which also have a role in coral reef ecosystems, it is necessary to conduct research on the condition of sea urchins population and the percentage of coral reefs on Poncan Godang Island. Sea urchin and coral reef data were collected using the Line Intercept Transect (LIT) method by monitoring directly on the transect line along 50 meters. The results obtained indicate that the population of sea urchins in the waters of Poncan Godang Island, North Sumatra can be described, that sea urchins do not affect the coral reef ecosystem because at stations 1 and 5 there is no sea urchin and the percentage of coral cover is classified as bad, but at station 3 there are 32 individuals with coral reef cover conditions, while at stations with The percentage of good coral cover is that at station 4 there are only 25 individuals, as well as at station 2 where the percentage of coral cover is higher than station 3 and there are no sea urchins
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Dajka, Jan-Claas, Victoria Beasley, Gilberte Gendron, and Nicholas AJ Graham. "Investigating sea urchin densities critical to macroalgal control on degraded coral reefs." Environmental Conservation 48, no. 2 (January 13, 2021): 136–41. http://dx.doi.org/10.1017/s037689292000051x.
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SummaryThere is an assumption that tropical sea urchins are macroalgal grazers with the ability to control macroalgal expansion on degraded coral reefs. We surveyed abundances of Echinothrix calamaris, an urchin species common in the western Indian Ocean on 21 reefs of the inner Seychelles and predicted their density using habitat predictors in a modelling approach. Urchin densities were greatest on patch reef habitat types and declined with increasing macroalgal cover. Next, we experimentally investigated the macroalgae-urchin relationship by penning two sea urchin densities on macroalgal fields. Over six weeks, the highest density treatment (4.44 urchins m−2) cleared 13% of macroalgal cover. This moderate impact leads us to conclude that controlling macroalgal expansion is not likely to be one of the main functions of E. calamaris in the inner Seychelles given the current densities we found in our surveys (mean: 0.02 urchins m−2, maximum: 0.16 urchins m−2).
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Yamamori, Luna, and Makoto Kato. "Effect of a cold event on population and community of pit-inhabiting sea urchins in Western Pacific coasts." Journal of the Marine Biological Association of the United Kingdom 101, no. 5 (August 2021): 819–26. http://dx.doi.org/10.1017/s0025315421000680.
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AbstractCoastal tide pools in southern Japan are inhabited by the rock-boring sea urchin Echinostrephus molaris, which excavate pits in the substrate. These pits are subsequently used by non-boring sea urchins such as Anthocidaris crassispina and Echinometra sp. B, and the recolonized pits are often inhabited by a commensal limpet-like trochid snail species, Broderipia iridescens. We explored the population and community dynamics of these sea urchins and the limpet-like snail by monitoring occupancy of 512 pits in tide pools in Shirahama, Japan from May 2017–May 2019. Initially, nearly all pits were occupied by any one of the three sea urchin species, but an unusual cold event in February 2018 caused a mass die off of these sea urchins. After this event, occupancy decreased from 99% to 15%, and the tropical species Echinometra sp. B disappeared from the study pools. We observed slow population recovery of E. molaris and A. crassispina, provably via migration of sub-adults from the subtidal zone. Turnover rate of the pit-occupying sea urchin species was <1.0% before the cold event, but drastically increased after the cold event. Population size of the commensal snail decreased along with those of their host, but the rate of commensalism was constant at 50–55% throughout the study period, suggesting that these snails followed their host sea urchins repeating inter-pit migration. Despite mass mortality and slow recovery, the sea urchin density remained high enough to maintain persistent sea urchin barrens throughout the study period.
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Keats, D. W., D. H. Steele, and G. R. South. "Atlantic wolffish (Anarhichas lupus L.; Pisces: Anarhichidae) predation on green sea urchins (Strongylocentrotus droebachiensis (O.F. Mull.); Echinodermata: Echinoidea) in eastern Newfoundland." Canadian Journal of Zoology 64, no. 9 (September 1, 1986): 1920–25. http://dx.doi.org/10.1139/z86-288.
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The diet of the Atlantic wolffish was studied by examining the contents of the gastrointestinal tracts of 90 individuals collected from the sea urchin dominated rocky subtidal in eastern Newfoundland. Green sea urchins comprised 75% of the overall diet by weight. Horse mussels ranked second but comprised only 9.5% of the diet. The remainder of the diet consisted of several species of invertebrates and fish. The average (over the whole season) wolffish contained 120 g of urchins, equivalent to the biomass of urchins on 0.23 m2 in the middle of the urchin-dominated zone. During April–September, prior to breeding, the average male wolffish contained 174 g of urchins, and the average female contained 85 g of urchins, biomass values representing, respectively, 0.33 and 0.16 m2. Assuming that the contents of the gastrointestinal tract turn over every 3 days, it was calculated that during May through August each wolffish consumes on average 5.29 kg of urchins (males, 7.09 kg; females, 3.50 kg). Based on these figures, a density of 1 wolffish pair per 20 m2 would be required to consume the mean biomass (532 g m−2) of urchins present in the urchin-dominated zone in 1 year.
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Sari, Tiara Permata, Abd Rahman As-syakur, Yulianto Suteja, and Dwi Budi Wiyanto. "Hubungan Kepadatan Bulu Babi (Echinoidea) dan Tutupan Terumbu Karang pada Kawasan Intertidal Pantai Sanur." Journal of Marine and Aquatic Sciences 3, no. 2 (May 20, 2017): 134. http://dx.doi.org/10.24843/jmas.2017.v3.i02.134-141.
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Marine intertidal region is an area that is affected by the mainland. One of the ecosystems found in the intertidal area is the coral reef ecosystem. Urchin is one that lives on these ecosystems. Sanur Beach area has coral reefs and the intertidal zone is quite extensive. The many activities and cruise tourism in Sanur Beach will indirectly affect the life of coral reefs and associated animal in it in this case urchins. The purpose of this study was to determine the relationship density of sea urchins and coral reefs cover percentage in the intertidal area on Sanur Beach. Research done during low tide. Coral reef data collection method and the density of sea urchins using 5x5m quadratic transects were analyzed using Pear Person bivariate correlations. Urchin densities ranging between 0-2.04 ind/m2. The percentage cover coral reefs ranged from 0.1- 17.9%. High and low density of sea urchins and the percentage of coral reefs affected allegedly incompatibility place their lives and because of pressure from community activities in Sanur. The density of sea urchins and the percentage of coral cover has a significant relationship with a strong degree of correlation is 0.79. Positive direction on that relationship means that the higher percentage of coral reefs, the higher density of sea urchins. This assume in which they live almost the same that is in need of a hard substrate and urchins use of coral reefs as a shelter.
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Stien, Audun. "Effects of the parasitic nematode Echinomermella matsi on growth and survival of its host, the sea urchin Strongylocentrotus droebachiensis." Canadian Journal of Zoology 77, no. 1 (July 1, 1999): 139–47. http://dx.doi.org/10.1139/z98-159.
Full textAbstract:
It has been suggested that the parasitic nematode Echinomermella matsi significantly affects the population dynamics of its host, the sea urchin Strongylocentrotus droebachiensis. The effects of infection on both host fecundity and host survival may be of importance. The fecundity of sea urchins is related to their size. Negative effects of infection on host growth will therefore reduce reproductive rates. I estimated the effect of infection on host growth and survival in two naturally infected wild sea urchin populations using a capture-mark-recapture approach. Infected and uninfected sea urchins were captured and marked with unique tags or recaptured seven times from June 1994 to September 1996. The increment in the diameter of marked sea urchins between captures was used to measure sea urchin growth. The effect of E. matsi infection on host growth was small. Mortality rates were estimated using survival probability models based on the methodology developed by Cormack, Jolly, and Seber. The effect of infection on host survival was pronounced, with estimated sea urchin life expectancies reduced by 33-86% by E. matsi infection. This suggests that E. matsi may affect the population dynamics of S. droebachiensis significantly through the effect on host survival.
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Ristanto, Andi, Ari Hepi Yanti, and Tri Rima Setyawati. "Sea Urchin (Echinoidea) Distribution and Abundance in the Intertidal Zone of Bengkayang Regency." Biosaintifika: Journal of Biology & Biology Education 10, no. 1 (April 2, 2018): 32–40. http://dx.doi.org/10.15294/biosaintifika.v10i1.9763.
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Sea urchins is the member of Echinoidea. This species can be found in tropical marine water to the poles. The study aimed to know the types, the abundance and spread of sea urchins in Bengkayang Regency. The research, used the transect method. Each station consisted of 3 transects with a length of 50 meters from the shore into the sea with the distance of 10 meters among the transects. This research obtained five species consisting of three species of the Diadema (genus) and two species of the Echinotrix (genus) i.e. Diadema antillarium, D. savignyi, D. setosum, Echinotrix calamaris and E. deadema. The density of sea urchins in Lemukutan Island ranges from 273 – 453 ind/Ha. The Density of sea urchins on Penata Kecil island ranges from 167 - 347 ind / Ha and on Penata Besar Island has a range from 307 - 387 ind/Ha. The highest diversity of sea urchins was found in Penata Kecil Island of (1.2355). The distribution of sea urchins in Lemukutan and Penata Besar Island was categorized into clumped and evenly distributed, while the distribution of sea urchin on Penata Kecil Island is included in the clustered and random categories. Distribution of sea urchins on the island is influenced by several factors such as sea water waves and food contained in the environment.
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Fitriyani, Fitriyani, Didik Santoso, and Karnan Karnan. "Abundance and Distribution Patterns of Sea Urchins (Echinoidea) at Lakey Beach, Hu'u District, Dompu Regency." Jurnal Biologi Tropis 22, no. 1 (January 27, 2022): 277–88. http://dx.doi.org/10.29303/jbt.v22i1.3119.
Full textAbstract:
Sea urchins are marine biota that have many benefits for life, so there is a need for information about the existence of sea urchins. The existence of sea urchins in marine ecosystems has a significant influence on the ecological balance, one of which is for coral reefs, because sea urchins are one of the control of macroalgae populations. The purpose of this study was to determine the species abundance, diversity index, dominance index and distribution pattern of sea urchins (Echinoidea) at Lakey Beach, Hu'u District, Dompu Regency. This type of research is descriptive exploratory using purposive sampling method (chosen method) in determining the three research stations. The data obtained were analyzed using the species formula, the Shanon Wienner diversity index, the Simpson dominance index, and the Morisita index. The results showed that the highest species on the Lakey Coast were Echinometra mathei with values of 0.60 Ind/mò and Echinometra viridis with values of 0.45 Ind/mò. The diversity index of sea urchins at Lakey Beach is included in the moderate criteria with a species diversity index value of H'=1.03. The sea urchin dominance index in Lakey Beach is included in the low criteria with a species dominance index of 0.42. The distribution pattern of sea urchins on Lakey Beach includes two criteria, namely flocking and uniform. Types of sea urchins that belong to a grouped distribution pattern are Echinometra mathei and Echinometra viridis. While the types of sea urchins that have a uniform distribution pattern are Diadema setosum, Echinotrix calamaris (brown striped spines), Mespilia globulus, and Tripneustus gratilia. This research can be used as a reference and source of information to see the condition of the ecosystem in Lakey Beach, Hu'u District, Dompu Regency. So that the community and can preserve marine life such as sea urchins (Echinoidea) so that their lives can be maintained.
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Schuster, Jasmin M., A. Kurt Gamperl, Patrick Gagnon, and Amanda E. Bates. "Distinct realized physiologies in green sea urchin (Strongylocentrotus droebachiensis) populations from barren and kelp habitats." FACETS 7 (January 1, 2022): 822–42. http://dx.doi.org/10.1139/facets-2021-0125.
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Overgrazing of habitat-forming kelps by sea urchins is reshaping reef seascapes in many temperate regions. Loss of kelp, in particular as a food source, may alter individual consumer physiology, which in turn may impair their ability to respond to climate warming. Here, we measured the temperature dependence of absolute and mass-independent oxygen consumption ([Formula: see text]) using two different exposure protocols (acute exposure and temperature “ramping”), as proxies of realized physiology, between green sea urchin ( Strongylocentrotus droebachiensis) populations from neighbouring barren and kelp habitats. Sea urchins from kelp habitats consumed 8%–78% more oxygen than sea urchins from barrens (across the range of temperatures tested (4–32 °C)) and had higher maximum [Formula: see text] values (by 26%). This was in part because kelp urchins typically had greater body masses. However, higher mass-independent [Formula: see text] values of kelp urchins suggest metabolic plasticity in response to habitat per se. In addition, the [Formula: see text] of sea urchins from kelp habitats was less sensitive to increases in temperature. We conclude that sea urchins from barren and kelp habitats of comparable body mass represent different energetic units. This highlights that habitat type can drive population-level variation that may shape urchins activities and environmental impact. Such variation should be integrated into energy-based models.
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Kresnamurti, Angelica, Farizah Izazi, and Dwi Kurniawati. "STANDARDISASI EKSTRAK ETANOL 96% BULU BABI Echinometra mathaei DARI PERAIRAN BANGKALAN." Journal of Herbal, Clinical and Pharmaceutical Science (HERCLIPS) 2, no. 1 (March 27, 2021): 21. http://dx.doi.org/10.30587/herclips.v2i1.2211.
Full textAbstract:
Echinometra mathaei sea urchins are known to contain chemical compounds that can be used to overcome health problems, one of which has antioxidant activity. Some previous studies have explained the benefits of sea urchins but to ensure the quality assurance of sea urchins extracts, efforts should be made to determine the quality standards of sea urchins extract. This study aims to standardize specific parameters and non-specific parameters on Echinometra mathaei sea urchins extract to ensure the quality of 96% ethanol extract. Samples were obtained from Rongkang Beach, Kwanyar District, Bangkalan District, Madura which were then extracted using maceration method with 96% ethanol solvent. The results of the study for specific parameters showed that organoleptically and macroscopically the extracts were thick, blackish brown in color and characteristic of sea urchins; levels of dissolved compounds in ethanol of 78.37%; levels of dissolved compounds in water of 93.09%; and chemical content tests showed that the extract contained steroid compounds, tannins, flavonoids, saponins, alkaloids and terpenoids. Determination of non-specific parameters showed that Echinometra mathaei sea urchin extract had a drying shrinkage of 3.03%; specific gravity of 0.8411 g/mL; water content of 5.32%; Pb heavy metal contamination was 7.28 mg/kg, Cd was <0.0024 mg/kg, Hg was <0.0002 mg / kg, Mg was 347.83 mg / kg; microbial contamination of <10 colonies / mL; and yeast mold contamination of <10 colonies/mL. The conclusion is Echinometra mathaei sea urchin extract has the potential to be developed into a medicinal preparation. Key word: Echinometra mathaei, Specific standardize parameters, non-specific standardize parameters, Extract thanol 96%.
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Milla, Mordekhai Rahenri, and Firat Meiyasa. "KARAKTERISTIK KIMIAWI KECAP BULU BABI (Diadema setosum) DENGAN LAMA FERMENTASI YANG BERBEDA." Marinade 5, no. 01 (April 30, 2022): 10–18. http://dx.doi.org/10.31629/marinade.v5i01.4128.
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Sea urchin (Diadema setosum) is one type of marine biota that can be used as a food source. The processing of sea urchins as fermented food, especially soy sauce products, has not been reported until now, while it is known that sea urchins have good nutrition. The purpose of this study was to evaluate chemical compositions such as pH, moisture content, ash content, fat content, protein content, carbohydrates in sea urchin soy sauce with different fermentation times. The results showed that the chemical composition of sea urchin (Diadema setosum) with different fermentation time had a pH value of 5.54 - 6.57, water content of 86.35 % - 87.28%, ash content of 3.55% - 3.64%, fat content of 3.78%. - 4.81%, protein content of 3.60% - 4.07%, and carbohydrates of 0.98%. Thus, this sea urchin soy sauce has the potential to be developed as a food additive
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Rechsteiner, Erin, and Angeleen Olson. "Harlequin Ducks (Histrionicus histrionicus) Scavenge Sea Urchin Fragments from Foraging Sea Otters (Enhydra lutris)." Canadian Field-Naturalist 130, no. 2 (April 1, 2016): 91. http://dx.doi.org/10.22621/cfn.v130i2.1832.
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Foraging animals may risk association with potential predators to obtain otherwise inaccessible prey. We observed this strategy in wintering Harlequin Ducks (Histrionicus histrionicus) scavenging fragments of Red Sea Urchins (Mesocentrotus franciscanus) from foraging Sea Otters (Enhydra lutris) that were re-occupying an area from which they had been ecologically absent since about 1850. Harlequin Ducks, like other sea ducks, have not previously been reported scavenging from other birds or mammals. In British columbia, Red Sea Urchins have reached large sizes and densities since the removal of Sea Otter predators by the marine fur trade in the 18th and 19th centuries. Observations of Sea Otters and Harlequin Ducks were made in 4 areas, spanning a time gradient of Sea Otter occupation from 1 to 5 years. During 3 months of observations (December 2013 – February 2014), Harlequin Ducks were associated with foraging Sea Otters only at sites that were recently occupied by Sea Otters (≤ 2 months), where the proportion of urchins in Sea Otter diets was highest and where the ducks acquired urchin fragments from foraging Sea Otters. We suggest that Sea Otters re-occupying their historic range and consuming predominantly large Red Sea Urchins provide a temporarily available prey subsidy for Harlequin Ducks. Our observations document a novel effect of Sea Otters providing important prey supplementation to a marine bird when foraging in urchin-rich habitats, contributing to the overall role of Sea Otters as a keystone species.
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Sanderson, J. C., S. D. Ling, J. G. Dominguez, and C. R. Johnson. "Limited effectiveness of divers to mitigate ‘barrens’ formation by culling sea urchins while fishing for abalone." Marine and Freshwater Research 67, no. 1 (2016): 84. http://dx.doi.org/10.1071/mf14255.
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Climate-driven incursion of the long-spined sea urchin (Centrostephanus rodgersii) in eastern Tasmania has prompted calls for strong management intervention given the urchins’ capacity to overgraze kelp beds and cause local collapse of valuable reef fisheries. We examined the effectiveness of commercial divers culling C. rodgersii while undertaking otherwise normal fishing for black-lip abalone (Haliotis rubra). Diver effort appears to be driven by fishing yield and not the opportunity to maximise numbers of urchins culled; the greatest culls occurred on shorter dives when abalone fishing was poor. Despite culling thousands of urchins, divers culled urchins only from within a small proportion of the total barrens patches on particular reefs. Thus, urchin density, size-frequency of barrens patches, and benthic community structure showed no detectable change relative to ‘no-cull’ control reefs. Nonetheless, divers were effective in culling urchins in the few patches they targeted, and these patches were quickly recolonised by canopy-forming kelps. Ongoing urchin culling by abalone divers will increase resilience of the kelp habitats on which the valuable abalone fishery depends, but only at highly localised spatial scales (10m). The effectiveness of this control strategy is dependent on sustainable local harvest of abalone warranting recurrent diver visitation to affected sites. However, abalone divers culling urchins while fishing are unlikely to control urchin densities at scales ≥102 m.
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Stark, Alyssa Y., Carla A. Narvaez, and Michael P. Russell. "Adhesive plasticity among populations of purple sea urchin (Strongylocentrotus purpuratus)." Journal of Experimental Biology 223, no. 15 (June 25, 2020): jeb228544. http://dx.doi.org/10.1242/jeb.228544.
Full textAbstract:
ABSTRACTSea urchins native to the nearshore open coast experience periods of high, repeated wave forces that can result in dislodgement. To remain attached while clinging and locomoting across rocky substrates, sea urchins use adhesive tube feet. Purple sea urchins (Strongylocentrotus purpuratus) adhere to a variety of rock substrates (e.g. sandstone, mudstone, granite), and display morphological plasticity (skeletal morphology) to native substrate. We tested the hypothesis that their adhesive system is also plastic and varies as a function of native population and substrate. The results of our study support our hypothesis. Sea urchins from sandstone adhere less strongly to most substrates than those native to mudstone and granite rock. Sandstone produced the lowest whole animal adhesive force values across all populations, suggesting that this rock type is particularly challenging for sea urchins to adhere to. The number of adhesive tube feet that failed during experimental trials and the area used by sea urchins to attach, matches closely with whole animal adhesive force values: higher forces resulted in more tube foot failure and larger attachment area. On artificial substrates (glass and Plexiglass), differences in adhesion among populations was consistent with differences in adhesion on rock substrates except on glass, where sea urchins native to sandstone adhered more strongly to glass than any other substrate tested. To our knowledge, this study is the first to describe population-level plasticity in a biological adhesive system related to native substrate, and has significant implications for sea urchin ecology, behavior and functional morphology.
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Rodríguez, Sebastián R., and José M. Fariña. "Effect of drift kelp on the spatial distribution pattern of the sea urchin Tetrapygus niger: a geostatistical approach." Journal of the Marine Biological Association of the United Kingdom 81, no. 1 (February 2001): 179–80. http://dx.doi.org/10.1017/s0025315401003587.
Full textAbstract:
Geostatistical analysis was used to investigate the effect of drift kelp on the spatial distribution of the sea urchin Tetrapygus niger. The positions of all sea urchins were mapped in four experimental plots in the rocky intertidal zone of the central Chilean coast. When drift macroalgae were added, the sea urchins left the substratum irregularities, increased in number inside the experimental plots, and tended to form a dense aggregation around the kelp. After the drift macroalgae was removed, the aggregations disappeared and the sea urchins returned to the depressions and/or interstices of the substratum. The results suggest that the influx of drift kelp is the triggering factor in the formation of dense aggregations of this species.
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Brady, Sheanna M., and Robert E. Scheibling. "Repopulation of the shallow subtidal zone by green sea urchins (Strongylocentrotus droebachiensis) following mass mortality in Nova Scotia, Canada." Journal of the Marine Biological Association of the United Kingdom 85, no. 6 (November 9, 2005): 1511–17. http://dx.doi.org/10.1017/s0025315405012713.
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Repopulation by green sea urchins Strongylocentrotus droebachiensis of a steeply sloping rock bottom was monitored at a wave-exposed headland (Chebucto Head) following a disease outbreak that caused mass mortality in September 1999. Density and size of urchins were sampled in four depth strata: at 8–10 m in an urchin grazing aggregation (front) along the lower margin of a kelp bed, at 12 m and 16 m on a bedrock ramp, and at 24 m on a cobble and boulder field where urchins were unaffected by the disease. Shoreward migration of adults along the ramp from the surviving population at 24 m was the primary means of repopulation, which was augmented by recruitment via planktonic larvae. At 16 m, urchin density stabilized (at ∼50 urchins m−2) within six months of the die-off while repopulation at 12 m took more than eight months. A grazing front of large urchins (40–60 mm, test diameter) had formed along the lower edge of a kelp bed by January 2002, which reached densities of up to 284 urchins m−2. Video surveys at Chebucto Head and two adjacent locations of similar bathymetry revealed an extensive urchin population between 25 and 55 m depth, with a mean density on rocky substrata of 73 urchins m−2.
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Keats, D. W., D. H. Steele, and G. R. South. "Ocean pout (Macrozoarces americanus (Bloch and Schneider) (Pisces: Zoarcidae)) predation on green sea urchins (Strongylocentrotus droebachiensis (O.F. Mull.) (Echinodermata: Echinoidea)) in eastern Newfoundland." Canadian Journal of Zoology 65, no. 6 (June 1, 1987): 1515–21. http://dx.doi.org/10.1139/z87-234.
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The diet of ocean pout was studied by analysis of the contents of the gastrointestinal tracts of 151 individuals collected from the green sea urchin dominated rocky subtidal in eastern Newfoundland. Green sea urchins constituted 62% of the overall diet by weight. The brittle star, Ophiopholus aculeata, constituted 7% of the diet, while the remainder was miscellaneous invertebrates and fish (mainly capelin and billfish). From April to July, when the fish are inshore and feeding, before breeding, the average ocean pout contained 56.3 g of urchins. This is a biomass of urchins equivalent to that in 0.106 m2 of the middle of the urchin-dominated zone. During the inshore feeding period, the average male ocean pout contained 65.0 g of urchins, and the average female contained 47.5 g, biomass values representing 0.122 and 0.089 m2, respectively. Assuming that the contents of the gastrointestinal tract turn over every 3 days, and assuming a 1:1 sex ratio, it is calculated that while inshore, before a seasonal reduction in feeding associated with the spawning season, each ocean pout consumes on average 2.29 kg of urchins (males 2.64 kg, females 1.93 kg). Based on these figures, a density of one ocean pout pair per 8.6 m2 would be required to completely consume the mean biomass (532 g m−2) of urchins present in the urchin-dominated zone in one season.
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Narvaez, CA, B. Sainte-Marie, and LE Johnson. "Intraspecific competition in size-structured populations: ontogenetic shift in the importance of interference competition in a key marine herbivore." Marine Ecology Progress Series 649 (September 10, 2020): 97–110. http://dx.doi.org/10.3354/meps13435.
Full textAbstract:
Individuals rarely have equal competitive abilities, with body size being one of the most important attributes affecting the mechanism (i.e. exploitative and interference) and consequences of competition. Competitive interactions within size-structured populations are complex and can have major implications for population dynamics, community structure and evolutionary processes. Destructive grazing of kelp beds by the green urchin Strongylocentrotus droebachiensis creates barrens where high-quality food is scarce and intraspecific competition may have an important role in structuring populations. In this study, we experimentally identified the mechanisms underlying size-asymmetric competition between small, medium, and large size classes of the green urchin. A field-based mesocosm experiment showed that small and medium sea urchins grew less and produced smaller gonads when competing for food with large conspecifics. Surprisingly, when food was provided ad libitum but large urchins were present, small individuals’ growth and foraging behavior were reduced, providing strong evidence for interference competition between small and large sea urchins. Interactions between medium and large sea urchins were, however, more influenced by exploitative competition, suggesting that sea urchins shift ontogenetically from a situation of intense interference competition to one dominated by exploitative competition. The size structure of the population can thus determine the relative importance of interference and exploitative competition. In turn, the importance of interference competition may influence size structure by inhibiting the growth of smaller urchins, a pattern consistent with the prediction of theoretical models. The consideration of size-asymmetric competitive interactions can lead to a better understanding of population size structure and dynamics.
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James, Philip, Tor Evensen, and Gunhild Johansson. "Effect of Season and Increased Temperature on Survival, Roe Enhancement, and Reproductive Cycle of the Green Sea Urchin (Strongylocentrotus droebachiensis) Collected from Four Relatively Close Sites in Northern Norway." Aquaculture Research 2023 (April 17, 2023): 1–10. http://dx.doi.org/10.1155/2023/6360865.
Full textAbstract:
A series of three trials were conducted in the North of Norway at different times of the year. The trials consisted of harvesting sea urchins from four sites, situated within 5 km of each other and then holding them in land-based enhancement facilities. They were held at ambient seawater temperatures as well as ambient plus 3.0°C. Samples were taken from the wild at the time of collection and at the end of the enhancement period as well as from the enhanced sea urchins from each site. Results showed that utilising the sea urchins from a variety of sites, even from areas where there is an abundance of sea urchins (sea urchin barrens) and the Gonad Index (GI) is almost always low, is viable in terms of the final, post roe enhancement GI. The results of the study indicate that differences in initial and final GI and the increase in GI between the sites, despite the relatively close proximity, show site selection is most likely not as important as ease of harvesting and sea urchin availability and the positive environmental impact from removal of sea urchins and these are the factors that harvesting strategies should focus on. The study has shown that it is possible to have a relatively consistent roe enhancement from S. droebachiensis from the North of Norway regardless of seasonality (time of year), site selection, and initial GI. Relatively small changes (up to 3°C) in the seawater temperature appear to have a slightly negative impact on enhancement efforts. However, this may vary when larger differences in temperature are experienced.
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Belleza, DFC, Y. Kawabata, T. Toda, and GN Nishihara. "Effects of dead conspecifics, hunger states, and seasons on the foraging behavior of the purple urchin Heliocidaris crassispina." Marine Ecology Progress Series 664 (April 15, 2021): 133–48. http://dx.doi.org/10.3354/meps13653.
Full textAbstract:
Trophic cascades are a powerful result of predator-prey relationships in an ecosystem. In aquatic environments, the signals associated with predators and predation are used by prey as a cue to avoid encountering predators when foraging for food. These behavioral cues can be powerful enough to control prey populations and indirectly protect primary producers. Here, we evaluated the effects of cues associated with predation on the purple urchin Heliocidaris crassispina and examined effects of hunger state and season, using time-lapse photography. A series of laboratory and in situ manipulative experiments were conducted to determine patterns of foraging behavior and behavioral modifications. We showed that starved urchins were less sensitive to predation cues compared to normally fed urchins. Field experiments indicated that 70% of fed urchins fled when exposed to a predation cue (presence of a dead urchin) whereas starved urchins remained regardless of the cue, supporting results from the laboratory using dead urchin and algal cues. Sea urchin activity and feeding rates were lower in winter-spring than in summer-autumn. Results suggest that hunger state has a large influence over the behavioral response of sea urchins, while also being affected by season due to metabolic control. In general, starvation appears to override predator avoidance behaviors, which exposes prey species to higher risks of predation.
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Guillou, Monique, Jacques Grall, and Solène Connan. "Can low sea urchin densities control macro-epiphytic biomass in a north-east Atlantic maerl bed ecosystem (Bay of Brest, Brittany, France)?" Journal of the Marine Biological Association of the United Kingdom 82, no. 5 (October 2002): 867–76. http://dx.doi.org/10.1017/s0025315402006276.
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The distribution, abundance and feeding behaviour of sea urchins (Paracentrotus lividus, Psammechinus miliaris, Sphaerechinus granularis) and the macro-algal biomass were assessed in two maerl beds within a north-east Atlantic coastal ecosystem (Bay of Brest, Brittany, France). To study the possible control of herbivorous sea urchins on the macrophytic algae, one maerl bed under the influence of urban sewage (northern site) was compared to one less influenced by urban and industrial outlets (southern site). Macrophytic biomass in the northern site was estimated as 40-fold higher than in the southern site where sea urchins were, on average, 38-times more numerous. Preliminary results support the hypothesis that grazing of sea urchin, even in low densities, can be a factor regulating the macrophytic biomass on maerl beds except in too nutrient enriched environments. So in the northern basin of the Bay, data pointed out the role of anthropogenic impacts on macrophytic biomass increase which was concomitant with the progressive disappearance of sensitive herbivorous species like sea urchins, both processes result in change in the ecosystem.
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Parson, Adrianna, Joseph Dirnberger, and Troy Mutchler. "Patterns of Dispersion, Movement and Feeding of the Sea Urchin Lytechinus variegatus, and the Potential Implications for Grazing Impact on Live Seagrass." Gulf and Caribbean Research 32 (2021): 8–18. http://dx.doi.org/10.18785/gcr.3201.03.
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The sea urchin Lytechinus variegatus is a known grazer of both living and dead tissue of turtlegrass, Thalassia testudinum, occasionally denuding large areas of seagrass. Field studies have attempted to assess effects of herbivory on seagrass by enclosing urchins at various densities. However, it is unclear how unrestricted urchins affect seagrass at lower densities more typically observed in the field. This study describes movement, feeding, and distribution of L. variegatus within beds of T. testudinum in St. Joseph Bay, Florida (USA) to quantify this urchin’s impact as a seagrass grazer. Urchins were absent from portions of seagrass beds closest to shore, present at low densities midway across the bed, and at highest densities (up to ~5 individuals/m2) at the offshore edge of the bed. Urchins tended not to aggregate, moved twice as rapidly where seagrass cover was reduced, and moved > 20X faster when placed in areas of open sand. Dead seagrass tissue occurred 4—30X more frequently on oral surfaces than living seagrass tissue. Fecal pellets with dead seagrass tissue were > 3X more common than pellets with live seagrass tissue. Injury to seagrass leaves was more common along dead leaf sections than live sections (> 2—10X). Overall, spatial distributions, movement, and diet indicate that L. variegatus at densities observed in this study would tend to have minimal effects on living seagrass. Episodic periods of denuding grassbeds reported in the literature suggest L. variegatus switches to live seagrass tissue as dead tissue becomes scarce during times of high urchin density.
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Wakano, Deli, and Laury Marcia Chara Huwae. "Struktur Komunitas Bulu Babi Di Perairan Pantai Kampung Baru Pulau Banda Kabupaten Maluku Tengah." Biosel: Biology Science and Education 9, no. 2 (November 23, 2020): 122. http://dx.doi.org/10.33477/bs.v9i2.1628.
Full textAbstract:
The waters of Kampung Baru Village are one of the waters in Banda Island, Central Maluku Regency, which has an abundance of marine life. The substrate conditions in these waters are rocky, rocky and sandy, surrounded by seagrass. On the coast of Kampung Baru Village, there are many marine biota, including crustaceans, gastropods, bivalves, echinoderms, sea cucumbers, starfish and others. Sea urchins are one of the most important biota because people in Kampung Baru Village use their gonads for daily consumption. The existence of sea urchins in coral reef ecosystems has a significant effect on the ecological balance. The purpose of this study was to determine the community structure of sea urchins in the coastal areas of Kampung Baru, Central Maluku Regency. It is necessary to do so so that the presence of sea urchins can be known so that the balance is well monitored. The method used is a quadratic linear transect. The results showed that the diversity of sea urchin species on the coast of the village of Kampung Baru, Banda Island, Central Maluku was 0.815, including the low category. The value of dominance is 0.512, which means there is a tendency for species to dominate. The density value is 0.065 and the distribution value is 0.277 which is included in the uniform category.
Keywords: Community Structure, Sea Urchins, Kampung Baru, Banda Island
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Chu, Yiru, De-Sing Ding, Wei-Ting Sun, Cyril Glenn Satuito, and Chih-Hung Pan. "Effects of Marine Microalgae on the Developmental Growth of the Sea Urchin Larviculture Anthocidaris crassipina." Fishes 8, no. 6 (May 24, 2023): 278. http://dx.doi.org/10.3390/fishes8060278.
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The sea urchin is a very important aquatic economic organism in many countries and has high food value. However, it has recently been heavily fished, and it would be of great importance to the sustainable development of coral reefs to develop large-scale aquaculture of sea urchins. Sea urchins are prone to death during larval development. Therefore, in this study, three kinds of microalgae were used as the initial food for sea urchins to evaluate whether different kinds of microalgae can improve their survival and growth rates. Chaetoceros muelleri (C), Isochrysis galbana tml (I), and Dunaliella salina (D) were fed to A. crassipina at concentrations of 5000, 10,000, 20,000, and 30,000 cell mL−1. A fasted group was used as control (N). The final body length, final body width, final stomach length, rudiment length, survival rate and morphology were measured to evaluate development and growth. The results showed that feeding with C. muelleri resulted in better growth and survival. After 9 days of feeding with C(20,000 cells mL−1), the rudiment length reached 203.33 ± 12.47 µm. The onset of metamorphosis was observed 12 days post-feeding. The survival rate after feeding C was also significantly higher than that after feeding I and D. In summary, when sea urchins are breeding, it is recommended to choose C(20,000 cells mL−1) or C(30,000 cells mL−1) as the initial feed for larvae to increase the growth and survival of sea urchin seedlings.
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Mao, Chai-An, Cavit Agca, Julie A. Mocko-Strand, Jing Wang, Esther Ullrich-Lüter, Ping Pan, Steven W. Wang, Maria Ina Arnone, Laura J. Frishman, and William H. Klein. "Substituting mouse transcription factor Pou4f2 with a sea urchin orthologue restores retinal ganglion cell development." Proceedings of the Royal Society B: Biological Sciences 283, no. 1826 (March 16, 2016): 20152978. http://dx.doi.org/10.1098/rspb.2015.2978.
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Pou domain transcription factor Pou4f2 is essential for the development of retinal ganglion cells (RGCs) in the vertebrate retina. A distant orthologue of Pou4f2 exists in the genome of the sea urchin (class Echinoidea) Strongylocentrotus purpuratus ( SpPou4f1/2 ), yet the photosensory structure of sea urchins is strikingly different from that of the mammalian retina. Sea urchins have no obvious eyes, but have photoreceptors clustered around their tube feet disc. The mechanisms that are associated with the development and function of photoreception in sea urchins are largely unexplored. As an initial approach to better understand the sea urchin photosensory structure and relate it to the mammalian retina, we asked whether SpPou4f1/2 could support RGC development in the absence of Pou4f2 . To answer this question, we replaced genomic Pou4f2 with an SpPou4f1/2 cDNA. In Pou4f2 -null mice, retinas expressing SpPou4f1/2 were outwardly identical to those of wild-type mice. SpPou4f1/2 retinas exhibited dark-adapted electroretinogram scotopic threshold responses, indicating functionally active RGCs. During retinal development, SpPou4f1/2 activated RGC-specific genes and in S. purpuratus , SpPou4f2 was expressed in photoreceptor cells of tube feet in a pattern distinct from Opsin4 and Pax6. Our results suggest that SpPou4f1/2 and Pou4f2 share conserved components of a gene network for photosensory development and they maintain their conserved intrinsic functions despite vast morphological differences in mouse and sea urchin photosensory structures.
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Solari, Paolo, Giorgia Sollai, Viviana Pasquini, Angelica Giglioli, Roberto Crnjar, and Piero Addis. "Blue-Green Algae as Stimulating and Attractive Feeding Substrates for a Mediterranean Commercial Sea Urchin Species, Paracentrotus lividus." Life 13, no. 7 (July 5, 2023): 1510. http://dx.doi.org/10.3390/life13071510.
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Sea urchins rely on chemical senses to localize suitable food resources, therefore representing model species for chemosensory studies. In the present study, we investigated the chemical sensitivity of the Mediterranean sea urchin Paracentrotus lividus to the blue-green alga Aphanizomenon flos-aquae, namely “Klamath”, and to a few amino acids chosen from the biochemical composition of the same algae. To this end, we used the “urchinogram” method, which estimates the movement rate of the sea urchins in response to chemicals. Our results showed that Klamath represents a strong chemical stimulus for P. lividus as it elicits an overall movement of spines, pedicellariae, and tube feet coupled, in some cases, to a coordinated locomotion of the animals. Sea urchins also displayed a sensitivity, even if to a lesser extent, to leucine, threonine, arginine, and proline, thus implying that the amino acids contained in Klamath may account, at least in part, for the stimulating effects exerted by the whole algae. Additionally, our results show that Klamath, as well as spirulina, another blue-green alga with high nutritional value, is very attractive for this sea urchin species. These findings gain further importance considering the potential profit of echinoderms for commercial consumers and their growing role in aquaculture. Klamath and spirulina combine high nutritional profiles with attractive and stimulating abilities and may be considered potential valuable feed supplements in sea urchin aquaculture.
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Brasseur, Lola, Guillaume Caulier, Patrick Flammang, Pascal Gerbaux, and Igor Eeckhaut. "Mapping of Spinochromes in the Body of Three Tropical Shallow Water Sea Urchins." Natural Product Communications 13, no. 12 (December 2018): 1934578X1801301. http://dx.doi.org/10.1177/1934578x1801301222.
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Sea urchin pigments, also known as spinochromes or polyhydroxynaphthoquinones (PHNQ) have been well studied for their bioactive properties like anti-bacterial, fungicidal, antioxidant and pro-inflammatory effects. Moreover, many studies have analyzed and identified these pigments in sea urchin tests and spines but, and to the best of our knowledge, never in their body compartments or in a quantitative manner. The aim of this work was to investigate the diversity and concentration of pigments in three sea urchins localized in the same coral reef in Madagascar ( Diadema savignyi, Tripneustes gratilla and Toxopneustes pileolus). Their pigment distribution patterns were compared and linked to their behavior in order to understand better the implication of spinochromes in a sea urchin's life. Analyses and quantifications by LC-MS showed the presence of 11 different spinochromes with principally two kinds of patterns. First, D. savignyi showed a high concentration in all its body compartments with a predominance for Echinochrome A and Spinochrome D – Iso 3, a pattern close to the E. mathaei distribution found in our previous study. The presence of these pigments has been linked to their bioactive properties and suggested their implications in UV radiation protection, in reproduction, in feeding as well as in their immune systems. Secondly, T. gratilla and T. pileolus presented few spinochromes, which could explain their restricted diet and their covering behavior facing sunlight. Moreover, the absence of pigments in their gonads could be explained by their seasonal spawning occurring before our collection period. Nevertheless, the near absence of spinochromes may be counterbalanced by other bioactive compounds like their toxic proteins, which may act as either a defense mechanism or immune agents, or like carotenoid pigments already shown in sea urchin and acting as defense agents. In conclusion, spinochromes, and pigments in general, seem to play many roles in sea urchin ecology. Their highly reactive structures confer them with strong bioactive properties involved in most parts of their metabolic system and clearly participate in the survival of the sea urchins.
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Sigg, Jessica E., Karena M. Lloyd-Knight, and Jean Geary Boal. "UV radiation influences covering behaviour in the urchin Lytechinus variegatus." Journal of the Marine Biological Association of the United Kingdom 87, no. 5 (October 2007): 1257–61. http://dx.doi.org/10.1017/s0025315407055865.
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Many species of sea urchins cover their bodies with a variety of materials. One hypothesis for this behaviour is that the urchins are reducing their exposure to UV radiation. The effect of UV radiation on the covering behaviour of twelve sea urchins, Lytechinus variegatus, was recorded and the shells used as covering materials were quantified. During UV exposure, urchins used significantly greater numbers, areas and masses of shells than did urchins during non-UV exposure. Results suggest that not only were L. variegatus covering in response to UV exposure, but they were also making distinct choices regarding preferred covering items. Unlike in previous studies, the urchins did not simply choose familiar objects or even the lightest objects; rather, when exposed to UV radiation they selected intermediate-sized objects, perhaps demonstrating a trade-off between the energetic costs of carrying objects and the physiological costs of exposure to UV radiation. While there appear to be many reasons for why urchins cover, these results indicate that urchin covering is non-random and has important functional significance.
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Brothers, Cecilia J., William J. Van Der Pol, Casey D. Morrow, Joseph A. Hakim, Hyunmin Koo, and James B. McClintock. "Ocean warming alters predicted microbiome functionality in a common sea urchin." Proceedings of the Royal Society B: Biological Sciences 285, no. 1881 (June 20, 2018): 20180340. http://dx.doi.org/10.1098/rspb.2018.0340.
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The microbiome of sea urchins plays a role in maintaining digestive health and innate immunity. Here, we investigated the effects of long-term (90 day) exposure to elevated seawater temperatures on the microbiome of the common, subtropical sea urchin Lytechinus variegatus . The community composition and diversity of microbes varied according to the type of sample collected from the sea urchin (seawater, feed, intestines, coelomic fluid, digested pellet and faeces), with the lowest microbial diversity (predominately the order Campylobacterales) located in the intestinal tissue. Sea urchins exposed to near-future seawater temperatures maintained the community structure and diversity of microbes associated with their tissues. However, marginal, non-significant shifts in microbial community structure with elevated temperature resulted in significant changes in predicted metagenomic functions such as membrane transport and amino acid and carbohydrate metabolism. The predicted changes in key metabolic categories suggest that near-future climate-induced increases in seawater temperature could shift microbial community function and impact sea urchin digestive and immune physiology.
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Stiefel, Klaus, and Glyn Barrett. "Sea Urchins as an Inspiration for Robotic Designs." Journal of Marine Science and Engineering 6, no. 4 (October 10, 2018): 112. http://dx.doi.org/10.3390/jmse6040112.
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Neuromorphic engineering is the approach to intelligent machine design inspired by nature. Here, we outline possible robotic design principles derived from the neural and motor systems of sea urchins (Echinoida). Firstly, we review the neurobiology and locomotor systems of sea urchins, with a comparative emphasis on differences to animals with a more centralized nervous system. We discuss the functioning and enervation of the tube feet, pedicellariae, and spines, including the limited autonomy of these structures. We outline the design principles behind the sea urchin nervous system. We discuss the current approaches of adapting these principles to robotics, such as sucker-like structures inspired by tube feet and a robotic adaptation of the sea urchin jaw, as well as future directions and possible limitations to using these principles in robots.
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Malakhoff, Katrina D., and Robert J. Miller. "After 15 years, no evidence for trophic cascades in marine protected areas." Proceedings of the Royal Society B: Biological Sciences 288, no. 1945 (February 17, 2021): 20203061. http://dx.doi.org/10.1098/rspb.2020.3061.
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In marine ecosystems, fishing often targets predators, which can drive direct and indirect effects on entire food webs. Marine reserves can induce trophic cascades by increasing predator density and body size, thereby increasing predation pressure on populations of herbivores, such as sea urchins. In California's northern Channel Islands, two species of sea urchins are abundant: the red urchin Mesocentrotus franciscanus , which is targeted by an economically valuable fishery, and the virtually unfished purple urchin Strongylocentrotus purpuratus . We hypothesized that urchin populations inside marine reserves would be depressed by higher predation, but that red urchins would be less affected due to fishing outside reserves. Instead, our analyses revealed that purple urchin populations were unaffected by reserves, and red urchin biomass significantly increased in response to protection. Therefore, urchin biomass overall has increased inside reserves, and we found no evidence that giant kelp is positively affected by reserves. Our results reveal the overwhelming direct effect of protecting fished species in marine reserves over indirect effects that are often predicted but seldom clearly documented. Indirect effects due to marine reserves may eventually occur in some cases, but very effective predators, large reserves or extended time periods may be needed to induce them.