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Статті в журналах з теми "Sharks Physiology"

Автор: Grafiati

Опубліковано: 4 червня 2021

Оновлено: 29 січня 2023

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1

Leigh, Samantha C., Yannis Papastamatiou, and Donovan P. German. "The nutritional physiology of sharks." Reviews in Fish Biology and Fisheries 27, no. 3 (May 25, 2017): 561–85. http://dx.doi.org/10.1007/s11160-017-9481-2.

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2

Whitney, Nicholas M., Karissa O. Lear, John J. Morris, Robert E. Hueter, John K. Carlson, and Heather M. Marshall. "Connecting post-release mortality to the physiological stress response of large coastal sharks in a commercial longline fishery." PLOS ONE 16, no. 9 (September 15, 2021): e0255673. http://dx.doi.org/10.1371/journal.pone.0255673.

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Анотація:

Bycatch mortality is a major factor contributing to shark population declines. Post-release mortality (PRM) is particularly difficult to quantify, limiting the accuracy of stock assessments. We paired blood-stress physiology with animal-borne accelerometers to quantify PRM rates of sharks caught in a commercial bottom longline fishery. Blood was sampled from the same individuals that were tagged, providing direct correlation between stress physiology and animal fate for sandbar (Carcharhinus plumbeus, N = 130), blacktip (C. limbatus, N = 105), tiger (Galeocerdo cuvier, N = 52), spinner (C. brevipinna, N = 14), and bull sharks (C. leucas, N = 14). PRM rates ranged from 2% and 3% PRM in tiger and sandbar sharks to 42% and 71% PRM in blacktip and spinner sharks, respectively. Decision trees based on blood values predicted mortality with >67% accuracy in blacktip and spinner sharks, and >99% accuracy in sandbar sharks. Ninety percent of PRM occurred within 5 h after release and 59% within 2 h. Blood physiology indicated that PRM was primarily associated with acidosis and increases in plasma potassium levels. Total fishing mortality reached 62% for blacktip and 89% for spinner sharks, which may be under-estimates given that some soak times were shortened to focus on PRM. Our findings suggest that no-take regulations may be beneficial for sandbar, tiger, and bull sharks, but less effective for more susceptible species such as blacktip and spinner sharks.

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3

Kelly, Michael L., Errol R. P. Murray, Caroline C. Kerr, Craig A. Radford, Shaun P. Collin, John A. Lesku, and Jan M. Hemmi. "Diverse Activity Rhythms in Sharks (Elasmobranchii)." Journal of Biological Rhythms 35, no. 5 (June 11, 2020): 476–88. http://dx.doi.org/10.1177/0748730420932066.

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Sharks are an interesting group of vertebrates, as many species swim continuously to “ram” oxygen-rich seawater over their gills (ram ventilators), whereas other species “pump” seawater over their gills by manipulating buccal cavity volume while remaining motionless (buccal pumpers). This difference in respiratory physiology raises the question: What are the implications of these differences in lifestyle for circadian rhythms? We investigated the diel activity patterns of 5 species of sharks, including 3 ram ventilating species: the school shark ( Galeorhinus galeus), the spotted estuary smooth-hound ( Mustelus lenticulatus), and the spiny dogfish ( Squalus acanthias); and 2 buccal pumping species: the Port Jackson ( Heterodontus portusjacksoni) and draughtsboard ( Cephaloscyllium isabellum) sharks. We measured the amount, duration, and distance traveled while swimming over multiple days under a 12:12 light:dark light regime for all species and used modified light regimes for species with a clear diel rhythm in activity. We identified a surprising diversity of activity rhythms. The school shark and smooth-hound swam continuously; however, whereas the school shark swam at the same speed and covered the same distance during the day and night, the smooth-hound swam slower at night and traversed a shorter distance. A similar pattern was observed in the spiny dogfish, although this shark swam less overall. Both the Port Jackson and draughtsboard sharks showed a marked nocturnal preference for swimming. This pattern was muted and disrupted during constant light and constant dark regimes, although circadian organization of this pattern was maintained under certain conditions. The consequences of these patterns for other biological processes, such as sleep, remain unclear. Nonetheless, these 5 species demonstrate remarkable diversity within the activity rhythms of sharks.

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4

Benson, C. W., B. D. Shea, C. de Silva, D. Donovan, P. E. Holder, S. J. Cooke, and A. J. Gallagher. "Physiological consequences of varying large shark exposure on striped bass (Morone saxatilis)." Canadian Journal of Zoology 97, no. 12 (December 2019): 1195–202. http://dx.doi.org/10.1139/cjz-2019-0173.

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Large marine predators often aggregate seasonally in discrete locations to take advantage of optimal foraging conditions, leading to spatial and temporal variation in their exposure on other species. However, our understanding of the impacts this exposure may have on the behavior and physiology of prey is poor, especially in marine systems. Here, we evaluated the non-consumptive effects of potential exposure to large sharks (white sharks, Carcharodon carcharias (Linnaeus, 1758)) on the stress physiology of an economically important teleost, the striped bass (Morone saxatilis (Walbaum, 1792)), off Cape Cod, Massachusetts, USA. We sampled fish in habitats that varied significantly in shark exposure across 5 months and over 2 years, evaluating blood physiology stress indicators (i.e., cortisol, glucose, and lactate concentrations) and reflex impairment. None of the blood parameters were influenced by shark exposure, although we did observe subtle temperature and seasonal effects. One of the three reflex tests (the vertical orientation test) was negatively affected by shark exposure, although the mechanistic basis for this finding is unclear. This work supports the notion that predictable sources of predation pressure tend not to manifest in stress-related costs in free-ranging prey, which has implications for shaping our understanding of how large sharks influence ecosystems through non-consumptive effects.

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5

Esposito, Anaïs, Pierre Sasal, Éric Clua, Emese Meglécz, and Camille Clerissi. "Shark Provisioning Influences the Gut Microbiota of the Black-Tip Reef Shark in French Polynesia." Fishes 7, no. 6 (October 29, 2022): 312. http://dx.doi.org/10.3390/fishes7060312.

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There is an increasing interest in touristic observations of top predators in the wild. Sharks are probably the most sought-after animal in marine ecosystems by divers. Regulations have been put in place, and even if they are more or less respected, providing food is still used in some places in order to attract wild animals. Because of the difficulty in sampling shark guts, few studies have analyzed the microbiota of sharks, and none have evaluated the effect of feeding on this microbiota. In this work, we compare microbiota assemblages of black-tip sharks between sites with and without regular feeding. Our results revealed a significant feeding effect on both alpha and beta diversities of microbiota. Notably, the alpha diversity of fed sharks was lower than unfed sharks. We hypothesize that this result is related to a lower diversity of food intake by sharks in places where feeding is regularly provided. More studies need to be conducted in order to estimate the impact of feeding on shark physiology.

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6

Johnston, Emmett M., Lewis G. Halsey, Nicholas L. Payne, Alison A. Kock, Gil Iosilevskii, Bren Whelan, and Jonathan D. R. Houghton. "Latent power of basking sharks revealed by exceptional breaching events." Biology Letters 14, no. 9 (September 2018): 20180537. http://dx.doi.org/10.1098/rsbl.2018.0537.

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The fast swimming and associated breaching behaviour of endothermic mackerel sharks is well suited to the capture of agile prey. In contrast, the observed but rarely documented breaching capability of basking sharks is incongruous to their famously languid lifestyle as filter-feeding planktivores. Indeed, by analysing video footage and an animal-instrumented data logger, we found that basking sharks exhibit the same vertical velocity (approx. 5 m s −1 ) during breach events as the famously powerful predatory great white shark. We estimate that an 8-m, 2700-kg basking shark, recorded breaching at 5 m s −1 and accelerating at 0.4 m s −2 , expended mechanical energy at a rate of 5.5 W kg −1 ; a mass-specific energetic cost comparable to that of the great white shark. The energy cost of such a breach is equivalent to around 1/17th of the daily standard metabolic cost for a basking shark, while the ratio is about half this for a great white shark. While breaches by basking sharks must serve a different function to white shark breaches, their similar breaching speeds questions our perception of the physiology of large filter-feeding fish.

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7

Gallagher, Austin J., Erica R. Staaterman, Steven J. Cooke, and Neil Hammerschlag. "Behavioural responses to fisheries capture among sharks caught using experimental fishery gear." Canadian Journal of Fisheries and Aquatic Sciences 74, no. 1 (January 2017): 1–7. http://dx.doi.org/10.1139/cjfas-2016-0165.

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The response to capture is important in fisheries because it can reveal potential threats to species beyond fishing mortalities resulting from direct harvest. To date, the vast majority of studies assessing shark stress responses have used physiology or biotelemetry to look at sensitivity after capture, leaving a gap in our understanding of the behaviours of sharks during capture. We examined the behavioural responses of sharks to capture by attaching accelerometers to fishing gear and measuring the immediate and prolonged forces they exerted while on the line. We recorded acceleration vectors and derived the rate of intense fighting behaviours of 23 individual sharks comprising three species. Results suggest that blacktip sharks (Carcharhinus limbatus) exhibited intense bouts of fighting behaviour at the onset of hooking, while nurse (Ginglymostoma cirratum) and tiger sharks (Galeocerdo cuvier) displayed more subdued acceleration values during capture. We also obtained plasma lactate from a subset of individuals and detected a strong correlation with maximum acceleration. These results align with previously published values and suggest that shark movement during fisheries capture is an important factor during bycatch and catch-and-release interactions.

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8

Bouyoucos, IA, CA Simpfendorfer, S. Planes, GD Schwieterman, OC Weideli, and JL Rummer. "Thermally insensitive physiological performance allows neonatal sharks to use coastal habitats as nursery areas." Marine Ecology Progress Series 682 (January 20, 2022): 137–52. http://dx.doi.org/10.3354/meps13941.

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Coastal sharks can use shallow, nearshore habitats as nursery areas, which is a behaviour that may increase fitness. The ecological benefits of shark nursery areas are well studied; yet the physiological mechanisms that enable sharks to exploit coastal habitats, especially those that experience extreme and dynamic temperatures, remain understudied. We hypothesised that neonatal sharks are able to use thermally dynamic coastal habitats as nursery areas because temperature does not strongly affect their physiology. To test this hypothesis, we defined patterns of nursery area use and temperature-dependent physiological performance in 2 reef shark species. First, we determined whether 10 sites around the island of Moorea, French Polynesia, satisfied nursery area criteria for neonate populations of blacktip reef sharks Carcharhinus melanopterus and sicklefin lemon sharks Negaprion acutidens using 5 consecutive years of abundance surveys. We then quantified effects of thermal exposure in situ on growth in recaptured individuals and quantified the temperature dependence of metabolic rate ex situ using respirometry. We found several potential C. melanopterus nursery areas, but during different sampling years, and identified 1 N. acutidens nursery area that remained consistent during the entire 5 yr study. In support of our hypothesis, growth and metabolic performance were not strongly affected by temperature in either species. Thus, thermally insensitive physiological performance may be a trait that elasmobranchs exhibit in thermally variable coastal habitats, including shark nursery areas. Together, this approach demonstrates how physiological and ecological concepts complement each other to improve our understanding of nursery area use in coastal shark populations.

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9

Jacoby, David M. P., Penthai Siriwat, Robin Freeman, and Chris Carbone. "Is the scaling of swim speed in sharks driven by metabolism?" Biology Letters 11, no. 12 (December 2015): 20150781. http://dx.doi.org/10.1098/rsbl.2015.0781.

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The movement rates of sharks are intrinsically linked to foraging ecology, predator–prey dynamics and wider ecosystem functioning in marine systems. During ram ventilation, however, shark movement rates are linked not only to ecological parameters, but also to physiology, as minimum speeds are required to provide sufficient water flow across the gills to maintain metabolism. We develop a geometric model predicting a positive scaling relationship between swim speeds in relation to body size and ultimately shark metabolism, taking into account estimates for the scaling of gill dimensions. Empirical data from 64 studies (26 species) were compiled to test our model while controlling for the influence of phylogenetic similarity between related species. Our model predictions were found to closely resemble the observed relationships from tracked sharks, providing a means to infer mobility in particularly intractable species.

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10

Ritter, Erich. "Sharks and their Relatives II: Biodiversity, Adaptive Physiology and Conservation." Bulletin of Marine Science 87, no. 1 (January 1, 2011): 155–56. http://dx.doi.org/10.5343/bms.br.2011.0001.

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11

Lowe, C. "Kinematics and critical swimming speed of juvenile scalloped hammerhead sharks." Journal of Experimental Biology 199, no. 12 (December 1, 1996): 2605–10. http://dx.doi.org/10.1242/jeb.199.12.2605.

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Kinematics and critical swimming speed (Ucrit) of juvenile scalloped hammerhead sharks Sphyrna lewini were measured in a Brett-type flume (635 l). Kinematic parameters were also measured in sharks swimming in a large pond for comparison with those of sharks swimming in the flume. Sharks in the flume exhibited a mean Ucrit of 65±11 cm s-1 (± s.d.) or 1.17±0.21 body lengths per second (L s-1), which are similar to values for other species of sharks. In both the flume and pond, tailbeat frequency (TBF) and stride length (LS) increased linearly with increases in relative swimming speed (Urel=body lengths traveled per second). In the flume, tailbeat amplitude (TBA) decreased with increasing speed whereas TBA did not change with speed in the pond. Differences in TBF and LS between sharks swimming in the flume and the pond decreased with increases in Urel. Sharks swimming at slow speeds (e.g. 0.55 L s-1) in the pond had LS 19 % longer and TBF 21 % lower than sharks in the flume at the same Urel. This implies that sharks in the flume expended more energy while swimming at comparable velocities. Comparative measurements of swimming kinematics from sharks in the pond can be used to correct for effects of the flume on shark swimming kinematics and energetics.

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12

Mohan, John A., Nathan R. Miller, Sharon Z. Herzka, Oscar Sosa-Nishizaki, Suzanne Kohin, Heidi Dewar, Michael Kinney, Owyn Snodgrass, and R. J. David Wells. "Elements of time and place: manganese and barium in shark vertebrae reflect age and upwelling histories." Proceedings of the Royal Society B: Biological Sciences 285, no. 1890 (November 7, 2018): 20181760. http://dx.doi.org/10.1098/rspb.2018.1760.

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As upper-level predators, sharks are important for maintaining marine food web structure, but populations are threatened by fishery exploitation. Sustainable management of shark populations requires improved understanding of migration patterns and population demographics, which has traditionally been sought through physical and/or electronic tagging studies. The application of natural tags such as elemental variations in mineralized band pairs of elasmobranch vertebrae cartilage could also reveal endogenous and exogenous processes experienced by sharks throughout their life histories. Here, elemental profiles were characterized in vertebrae encompassing complete life histories (birth-to-death) of shortfin mako ( Isurus oxyrinchus ), common thresher ( Alopias vulpinus ) and blue shark ( Prionace glauca ) of known tag and recapture locations in the eastern North Pacific Ocean. All sharks were injected with oxytetracycline at initial capture, released and subsequently recaptured, with individual liberty times ranging from 215 days to 6 years. Vertebral band pairs forming over the liberty intervals were verified by counting the number of band pairs deposited since the oxytetracycline band. Regular oscillations in vertebrae manganese (Mn) content corresponded well with the number of validated band pairs, suggesting that Mn variation could be used to age sharks. Increases in vertebrae barium concentration were correlated with times when individuals occupied areas with high coastal upwelling indices, the timing and spatial intensity of which varied from year to year. Interspecific relationships were probably influenced by behavioural differences in horizontal and vertical habitat use, feeding habits and thermoregulatory physiology. These results indicate that vertebral sclerochronology has the potential to advance our knowledge of elasmobranch life history including age and growth estimation and environmental reconstruction.

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13

GRAHAM, JEFFREY B., HEIDI DEWAR, N. C. LAI, WILLIAM R. LOWELL, and STEVE M. ARCE. "Aspects of Shark Swimming Performance Determined Using a Large Water Tunnel." Journal of Experimental Biology 151, no. 1 (July 1, 1990): 175–92. http://dx.doi.org/10.1242/jeb.151.1.175.

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A large, sea-going water tunnel was used in various studies of shark swimming performance. The critical swimming velocity (Ucrit, an index of aerobically sustainable swimming speed) of a 70 cm long lemon shark (Negaprion brevirostris Poey) was determined to be 1.1 Ls−1, where L is body length. The Ucrit of the leopard shark (Triakis semifasciata Girard) was found to vary inversely with body size; from about 1.6Ls−1in 30–50cm sharks to 0.6LS−1 in 120cm sharks. Large Triakis adopt ram gill ventilation at swimming speeds between 27 and 60cms−1, which is similar to the speed at which this transition occurs in teleosts. Analyses of tail-beat frequency (TBF) in relation to velocity and body size show that smaller Triakis have a higher TBF and can swim at higher relative speeds. TBF, however, approaches a maximal value at speeds approaching Ucrit, suggesting that red muscle contraction velocity may limit sustained swimming speed. The TBF of both Triakis and Negaprion rises at a faster rate with swimming velocity than does that of the more thunniform mako shark (Isurus oxyrinchus Rafinesque). This is consistent with the expectation that, at comparable relative speeds, sharks adapted for efficient swimming should have a lower TBF. The rates of O2 consumption of swimming lemon and mako sharks are among the highest yet measured for elasmobranchs and are comparable to those of cruise-adapted teleosts.

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14

Zemah-Shamir, Ziv, Shiri Zemah-Shamir, Aviad Scheinin, Dan Tchernov, Teddy Lazebnik, and Gideon Gal. "A Systematic Review of the Behavioural Changes and Physiological Adjustments of Elasmobranchs and Teleost’s to Ocean Acidification with a Focus on Sharks." Fishes 7, no. 2 (February 28, 2022): 56. http://dx.doi.org/10.3390/fishes7020056.

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In recent years, much attention has been focused on the impact of climate change, particularly via ocean acidification (OA), on marine organisms. Studying the impact of OA on long-living organisms, such as sharks, is especially challenging. When the ocean waters absorb anthropogenic carbon dioxide (CO2), slow-growing shark species with long generation times may be subjected to stress, leading to a decrease in functionality. Our goal was to examine the behavioral and physiological responses of sharks to OA and the possible impacts on their fitness and resilience. We conducted a systematic review in line with PRISMA-Analyses, of previously reported scientific experiments. We found that most studies used CO2 partial pressures (pCO2) that reflect representative concentration pathways for the year 2100 (e.g., pH ~7.8, pCO2 ~1000 μatm). Since there is a considerable knowledge gap on the effect of OA on sharks, we utilized existing data on bony fish to synthesize the available knowledge. Given the similarities between the behaviors and physiology of these two superclasses’ to changes in CO2 and pH levels, there is merit in including the available information on bony fish as well. Several studies indicated a decrease in shark fitness in relation to increased OA and CO2 levels. However, the decrease was species-specific and influenced by the intensity of the change in atmospheric CO2 concentration and other anthropogenic and environmental factors (e.g., fishing, temperature). Most studies involved only limited exposure to future environmental conditions and were conducted on benthic shark species studied in the laboratory rather than on apex predator species. While knowledge gaps exist, and more research is required, we conclude that anthropogenic factors are likely contributing to shark species’ vulnerability worldwide. However, the impact of OA on the long-term stability of shark populations is not unequivocal.

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15

Weng, K. C. "Satellite Tagging and Cardiac Physiology Reveal Niche Expansion in Salmon Sharks." Science 310, no. 5745 (October 7, 2005): 104–6. http://dx.doi.org/10.1126/science.1114616.

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16

Hussey, Nigel E., Sabine P. Wintner, Sheldon F. J. Dudley, Geremy Cliff, and David T. Cocks. "Questioning maternal resource allocation in sharks." Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 153, no. 2 (June 2009): S65. http://dx.doi.org/10.1016/j.cbpa.2009.04.006.

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17

Walker, Terence I. "The biology of sharks and rays." Marine and Freshwater Behaviour and Physiology 47, no. 2 (February 26, 2014): 129–33. http://dx.doi.org/10.1080/10236244.2014.889376.

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18

Wilga, C. D., and G. V. Lauder. "Three-dimensional kinematics and wake structure of the pectoral fins during locomotion in leopard sharks Triakis semifasciata." Journal of Experimental Biology 203, no. 15 (August 1, 2000): 2261–78. http://dx.doi.org/10.1242/jeb.203.15.2261.

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The classical theory of locomotion in sharks proposes that shark pectoral fins are oriented to generate lift forces that balance the moment produced by the oscillating heterocercal tail. Accordingly, previous studies of shark locomotion have used fixed-wing aircraft as a model assuming that sharks have similar stability and control mechanisms. However, unlike airplanes, sharks are propelled by undulations of the body and tail and have considerable control of pectoral fin motion. In this paper, we use a new approach to examine the function of the pectoral fins of leopard sharks, Triakis semifasciata, during steady horizontal swimming at speeds of 0.5-2.0ls(−1), where l is total body length, and during vertical maneuvering (rising and sinking) in the water column. The planar orientation of the pectoral fin was measured using three-dimensional kinematics, while fluid flow in the wake of the pectoral fin and forces exerted on the water by the fin were quantified using digital particle image velocimetry (DPIV). Steady horizontal swimming in leopard sharks is characterized by continuous undulations of the body with a positive body tilt to the flow that decreases from a mean of 11 degrees to 0.6 degrees with increasing flow speeds from 0. 5 to 2.0ls(−1). Three-dimensional analysis showed that, during steady horizontal locomotion, the pectoral fins are cambered, concave downwards, at a negative angle of attack that we predict to generate no significant lift. Leopard shark pectoral fins are also oriented at a substantial negative dihedral angle that amplifies roll moments and hence promotes rapid changes in body position. Vortices shed from the trailing edge of the pectoral fin were detected only during vertical maneuvering. Starting vortices are produced when the posterior plane of the pectoral fin is actively flipped upwards or downwards to initiate rising or sinking, respectively, in the water column. The starting vortex produced by the pectoral fin induces a pitching moment that reorients the body relative to the flow. Body and pectoral fin surface angle are altered significantly when leopard sharks change vertical position in the water column. Thus, locomotion in leopard sharks is not analogous to flight in fixed-wing aircraft. Instead, a new force balance for swimming leopard sharks is proposed for steady swimming and maneuvering. Total force balance on the body is adjusted by altering the body angle during steady swimming as well as during vertical maneuvering, while the pectoral fins appear to be critical for initiating maneuvering behaviors, but not for lift production during steady horizontal locomotion.

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19

Knotek, R. J., B. S. Frazier, T. S. Daly-Engel, C. F. White, S. N. Barry, E. J. Cave, and N. M. Whitney. "Post-release mortality, recovery, and stress physiology of blacknose sharks, Carcharhinus acronotus, in the Southeast U.S. recreational shark fishery." Fisheries Research 254 (October 2022): 106406. http://dx.doi.org/10.1016/j.fishres.2022.106406.

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20

Rosa, Rui, Jodie L. Rummer, and Philip L. Munday. "Biological responses of sharks to ocean acidification." Biology Letters 13, no. 3 (March 2017): 20160796. http://dx.doi.org/10.1098/rsbl.2016.0796.

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Анотація:

Sharks play a key role in the structure of marine food webs, but are facing major threats due to overfishing and habitat degradation. Although sharks are also assumed to be at relatively high risk from climate change due to a low intrinsic rate of population growth and slow rates of evolution, ocean acidification (OA) has not, until recently, been considered a direct threat. New studies have been evaluating the potential effects of end-of-century elevated CO 2 levels on sharks and their relatives' early development, physiology and behaviour. Here, we review those findings and use a meta-analysis approach to quantify the overall direction and magnitude of biological responses to OA in the species of sharks that have been investigated to date. While embryo survival and development time are mostly unaffected by elevated CO 2 , there are clear effects on body condition, growth, aerobic potential and behaviour (e.g. lateralization, hunting and prey detection). Furthermore, studies to date suggest that the effects of OA could be as substantial as those due to warming in some species. A major limitation is that all past studies have involved relatively sedentary, benthic sharks that are capable of buccal ventilation—no studies have investigated pelagic sharks that depend on ram ventilation. Future research should focus on species with different life strategies (e.g. pelagic, ram ventilators), climate zones (e.g. polar regions), habitats (e.g. open ocean), and distinct phases of ontogeny in order to fully predict how OA and climate change will impact higher-order predators and therefore marine ecosystem dynamics.

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21

Bernal, Diego, Douglas Syme, Jeanine Donley, and Chugey Sepulveda. "Divergent locomotor muscle design among thresher sharks." Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 153, no. 2 (June 2009): S67. http://dx.doi.org/10.1016/j.cbpa.2009.04.013.

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22

LITHERLAND, LENORE, SHAUN P. COLLIN, and KERSTIN A. FRITSCHES. "Eye growth in sharks: Ecological implications for changes in retinal topography and visual resolution." Visual Neuroscience 26, no. 4 (July 2009): 397–409. http://dx.doi.org/10.1017/s0952523809990150.

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AbstractThe visual abilities of sharks show substantial interspecific variability. In addition, sharks may change their habitat and feeding strategy throughout life. As the eyes of sharks continue to grow throughout the animal’s lifetime, ontogenetic variability in visual ability may also occur. The topographic analysis of the photoreceptor and ganglion cell distributions can identify visual specializations and assess changes in visual abilities that may occur concurrently with eye growth. This study examines an ontogenetic series of whole-mounted retinas in two elasmobranch species, the sandbar shark, Carcharhinus plumbeus, and the shortspine spurdog, Squalus mitsukurii, to identify regional specializations mediating zones for improved spatial resolution. The study examines retinal morphology and presents data on summation ratios between photoreceptor and ganglion cell layers, anatomically determined peak spatial resolving power, and the angular extent of the visual field. Peak densities of photoreceptors and ganglion cells occur in similar retinal locations. The topographic distribution of neurons in the ganglion cell layer does not differ substantially with eye growth. However, predicted peak spatial resolution increases with eye growth from 4.3 to 8.9 cycles/deg in C. plumbeus and from 5.7 to 7.2 cycles/deg in S. mitsukurii. The topographic distribution of different-sized ganglion cells is also mapped in C. plumbeus, and a population of large ganglion cells (soma area 120–350 μm2) form a narrow horizontal streak across the retinal meridian, while the spatial distribution of ordinary-sized ganglion cells (soma area 30–120 μm2) forms an area in the central retina. Species-specific retinal specializations highlight differences in visually mediated behaviors and foraging strategies between C. plumbeus and S. mitsukurii.

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23

Wilga, C. D., and G. V. Lauder. "Function of the heterocercal tail in sharks: quantitative wake dynamics during steady horizontal swimming and vertical maneuvering." Journal of Experimental Biology 205, no. 16 (August 15, 2002): 2365–74. http://dx.doi.org/10.1242/jeb.205.16.2365.

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SUMMARYThe function of the heterocercal tail in sharks has long been debated in the literature. Previous kinematic data have supported the classical theory which proposes that the beating of the heterocercal caudal fin during steady horizontal locomotion pushes posteroventrally on the water, generating a reactive force directed anterodorsally and causing rotation around the center of mass. An alternative model suggests that the heterocercal shark tail functions to direct reaction forces through the center of mass. In this paper,we quantify the function of the tail in two species of shark and compare shark tail function with previous hydrodynamic data on the heterocercal tail of sturgeon Acipenser transmontanus. To address the two models of shark heterocercal tail function, we applied the technique of digital particle image velocimetry (DPIV) to quantify the wake of two species of shark swimming in a flow tank. Both steady horizontal locomotion and vertical maneuvering were analyzed. We used DPIV with both horizontal and vertical light sheet orientations to quantify patterns of wake velocity and vorticity behind the heterocercal tail of leopard sharks (Triakis semifasciata) and bamboo sharks (Chiloscyllium punctatum) swimming at 1.0Ls-1, where L is total body length. Two synchronized high-speed video cameras allowed simultaneous measurement of shark body position and wake structure. We measured the orientation of tail vortices shed into the wake and the orientation of the central jet through the core of these vortices relative to body orientation. Analysis of flow geometry indicates that the tail of both leopard and bamboo shark generates strongly tilted vortex rings with a mean jet angle of approximately 30 ° below horizontal during steady horizontal swimming. The corresponding angle of the reaction force is much greater than body angle (mean 11 °) and the angle of the path of motion of the center of mass (mean approximately 0 °), thus strongly supporting the classical model of heterocercal tail function for steady horizontal locomotion. Vortex jet angle varies significantly with body angle changes during vertical maneuvering, but sharks show no evidence of active reorientation of jet angle relative to body angle, as was seen in a previous study on the function of sturgeon tail. Vortex jet orientation is significantly more inclined than the relatively horizontal jet generated by sturgeon tail vortex rings, demonstrating substantial differences in function in the heterocercal tails of sharks and sturgeon.We present a summary of forces on a swimming shark integrating data obtained here on the tail with previous data on pectoral fin and body function. Body orientation plays a critical role in the overall force balance and compensates for torques generated by the tail. The pectoral fins do not generate lift during steady horizontal locomotion, but play an important hydrodynamic role during vertical maneuvering.

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24

Kajiura, Stephen M., and Kim N. Holland. "Electroreception in juvenile scalloped hammerhead and sandbar sharks." Journal of Experimental Biology 205, no. 23 (December 1, 2002): 3609–21. http://dx.doi.org/10.1242/jeb.205.23.3609.

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SUMMARY The unique head morphology of sphyrnid sharks might have evolved to enhance electrosensory capabilities. The `enhanced electroreception' hypothesis was tested by comparing the behavioral responses of similarly sized carcharhinid and sphyrnid sharks to prey-simulating electric stimuli. Juvenile scalloped hammerhead sharks Sphyrna lewini and sandbar sharks Carcharhinus plumbeus oriented to dipole electric fields from the same maximum distance (approximately 30 cm) and thus demonstrated comparable behavioral-response thresholds (<1 nV cm-1). Despite the similarity of response threshold, the orientation pathways and behaviors differed for the two species. Scalloped hammerheads typically demonstrated a pivot orientation in which the edge of the cephalofoil closest to the dipole remained stationary while the shark bent its trunk to orient to the center of the dipole. By contrast, sandbars swam in a broader arc towards the center of the dipole. The different orientation patterns are attributed to the hydrodynamic properties of the cephalofoil, which enables the hammerheads to execute sharp turns at high speed. The greater trunk width of the sandbar sharks prevented them from demonstrating the same degree of flexibility. Therefore, although the sphyrnid head morphology does not appear to confer a greater sensitivity to prey-simulating dipole electric fields, it does provide(1) a greater lateral search area, which may increase the probability of prey encounter, and (2) enhanced maneuverability, which may aid in prey capture.

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25

Fudge, D. "CHILLY WATERS, HOT SHARKS." Journal of Experimental Biology 208, no. 23 (December 1, 2005): vii. http://dx.doi.org/10.1242/jeb.01944.

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26

Blackburn, L. "HOW SHARKS SENSE SMELLS." Journal of Experimental Biology 210, no. 11 (June 1, 2007): iii. http://dx.doi.org/10.1242/jeb.007427.

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27

Remme, Jannicke Fugledal, Marianne Synnes, and Iren S. Stoknes. "Chemical characterisation of eggs from deep-sea sharks." Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 141, no. 2 (June 2005): 140–46. http://dx.doi.org/10.1016/j.cbpc.2005.02.008.

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28

Arostegui, MC, P. Gaube, ML Berumen, A. DiGiulian, BH Jones, A. Røstad, and CD Braun. "Vertical movements of a pelagic thresher shark (Alopias pelagicus): insights into the species’ physiological limitations and trophic ecology in the Red Sea." Endangered Species Research 43 (December 3, 2020): 387–94. http://dx.doi.org/10.3354/esr01079.

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The pelagic thresher shark Alopias pelagicus is an understudied elasmobranch harvested in commercial fisheries of the tropical Indo-Pacific. The species is endangered, overexploited throughout much of its range, and has a decreasing population trend. Relatively little is known about its movement ecology, precluding an informed recovery strategy. Here, we report the first results from an individual pelagic thresher shark outfitted with a pop-up satellite archival transmitting (PSAT) tag to assess its movement with respect to the species’ physiology and trophic ecology. A 19 d deployment in the Red Sea revealed that the shark conducted normal diel vertical migration, spending the majority of the day at 200-300 m in the mesopelagic zone and the majority of the night at 50-150 m in the epipelagic zone, with the extent of these movements seemingly not constrained by temperature. In contrast, the depth distribution of the shark relative to the vertical distribution of oxygen suggested that it was avoiding hypoxic conditions below 300 m even though that is where the daytime peak of acoustic backscattering occurs in the Red Sea. Telemetry data also indicated crepuscular and daytime overlap of the shark’s vertical habitat use with distinct scattering layers of small mesopelagic fishes and nighttime overlap with nearly all mesopelagic organisms in the Red Sea as these similarly undergo nightly ascents into epipelagic waters. We identify potential depths and diel periods in which pelagic thresher sharks may be most susceptible to fishery interactions, but more expansive research efforts are needed to inform effective management.

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29

Abel, D. C., W. R. Lowell, J. B. Graham, and R. Shabetai. "Elasmobranch pericardial function 2. The influence of pericardial pressure on cardiac stroke volume in horn sharks and blue sharks." Fish Physiology and Biochemistry 4, no. 1 (July 1987): 5–14. http://dx.doi.org/10.1007/bf02073861.

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30

Jerome, J. M., A. J. Gallagher, S. J. Cooke, and N. Hammerschlag. "Integrating reflexes with physiological measures to evaluate coastal shark stress response to capture." ICES Journal of Marine Science 75, no. 2 (November 2, 2017): 796–804. http://dx.doi.org/10.1093/icesjms/fsx191.

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Abstract In both commercial and recreational fisheries, sharks are captured and released alive to comply with regulations or due to low economic value or voluntary conservation ethic. As a result, understanding the physiological and behavioural responses of sharks to capture stress is important for determining subsequent effects of fisheries interactions on a species-specific basis, as well as for identifying factors that influence mortality. Here, we employed a suite of conventional blood physiology endpoints (glucose, lactate, and haematocrit) integrated with assessments of reflex impairment on blacktip (Carcharhinus limbatus), great hammerhead (Sphyrna mokarran), nurse (Ginglymostoma cirratum) and sandbar sharks (Carcharhinus plumbeus) captured via experimental drumline gear. We documented a wide range of species-specific differences in all parameters assessed, with nurse sharks consistently having the lowest relative levels of physiological disturbance and reflex impairment; and with great hammerheads exhibiting the highest level of physiological disturbance and reflex impairment, suggesting higher vulnerability to fishing. In general, increases in lactate were positively associated with hook time and correlated with reflex impairment assessment. Moreover, reflex indices showed significant impairment with hook time, with the “jaw” reflex emerging as the most potential predictor of disturbance. Our study results connect previously reported species-specific at-vessel and post-release mortality rates to their physiological disturbance and reflex impairment.

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31

Ferry-Graham, LA. "Effects of prey size and mobility on prey-capture kinematics in leopard sharks triakis semifasciata." Journal of Experimental Biology 201, no. 16 (August 15, 1998): 2433–44. http://dx.doi.org/10.1242/jeb.201.16.2433.

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Recent work on teleosts suggests that attack behaviors or kinematics may be modified by a predator on the basis of the size of the prey or the ability of the prey to sense predators and escape capture (elusivity). Sharks are generally presumed to be highly visual predators; thus, it is reasonable to expect that they might also be capable of such behavioral modulation. In this study, I investigated the effect of prey item size and type on prey-capture behavior in leopard sharks (Triakis semifasciata) that had been acclimated to feeding in the laboratory. Using high-speed video, sharks were filmed feeding on two sizes of the same prey item (thawed shrimp pieces) and two potentially more elusive prey items (live earthworms and live mud shrimp). In leopard sharks, little effect of prey elusivity was found for kinematic variables during prey capture. However, the large proportion of successful captures of the live prey suggests that they did not prove to be truly elusive prey items for the leopard shark. There were significant size effects on prey-capture kinematics, with the larger non-elusive items inducing greater head expansion during prey capture. Ram-suction index values also indicated that strikes on large, non-elusive prey had a significantly larger suction component than strikes on similar small prey items. This finding is interesting given that the two sizes of non-elusive prey item offered no differential challenge in terms of a performance consequence (reduced capture success).

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32

Ritter, Erich Kurt. "Mouth gaping behavior in Caribbean reef sharks,Carcharhinus perezi." Marine and Freshwater Behaviour and Physiology 41, no. 3 (September 2008): 161–67. http://dx.doi.org/10.1080/10236240802373925.

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33

Buddle, Alice L., James U. Van Dyke, Michael B. Thompson, Colin A. Simpfendorfer, Christopher R. Murphy, Margot L. Day, and Camilla M. Whittington. "Structure and permeability of the egg capsule of the placental Australian sharpnose shark, Rhizoprionodon taylori." Journal of Comparative Physiology B 192, no. 2 (February 4, 2022): 263–73. http://dx.doi.org/10.1007/s00360-021-01427-0.

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AbstractShark placentae are derived from modifications to the fetal yolk sac and the maternal uterine mucosa. In almost all placental sharks, embryonic development occurs in an egg capsule that remains intact for the entire pregnancy, separating the fetal tissues from the maternal tissues at the placental interface. Here, we investigate the structure and permeability of the egg capsules that surround developing embryos of the placental Australian sharpnose shark (Rhizoprionodon taylori) during late pregnancy. The egg capsule is an acellular fibrous structure that is 0.42 ± 0.04 μm thick at the placental interface between the yolk sac and uterine tissues, and 0.67 ± 0.08 μm thick in the paraplacental regions. This is the thinnest egg capsule of any placental shark measured so far, which may increase the diffusion rate of respiratory gases, fetal wastes, water and nutrients between maternal and fetal tissues. Molecules smaller than or equal to ~ 1000 Da can diffuse through the egg capsule, but larger proteins (~ 3000–26,000 Da) cannot. Similar permeability characteristics between the egg capsule of R. taylori and other placental sharks suggest that molecular size is an important determinant of the molecules that can be exchanged between the mother and her embryos during pregnancy.

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34

Humphries, Nicolas E., and David W. Sims. "Modelling the movements and behaviour of sharks with Lévy statistics." Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 153, no. 2 (June 2009): S67. http://dx.doi.org/10.1016/j.cbpa.2009.04.015.

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35

van Bergen, Y. "NOT ALL THRESHER SHARKS KEEP WARM." Journal of Experimental Biology 208, no. 22 (November 15, 2005): i. http://dx.doi.org/10.1242/jeb.01937.

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36

Phillips, K. "KEEPING SHARKS WARM IN THE COLD." Journal of Experimental Biology 209, no. 14 (July 15, 2006): i—ii. http://dx.doi.org/10.1242/jeb.02390.

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37

Knight, K. "BOTTLES SHOW HOW SHARKS FILTER FEED." Journal of Experimental Biology 214, no. 10 (April 27, 2011): iii. http://dx.doi.org/10.1242/jeb.058784.

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38

Borowiec, Brittney G. "Whirlpools are hotspots for hungry sharks." Journal of Experimental Biology 222, no. 21 (October 31, 2019): JEB193102. http://dx.doi.org/10.1242/jeb.193102.

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39

Bernal, Diego, Joseph P. Reid, Julie M. Roessig, Shinsyu Matsumoto, Chugey A. Sepulveda, Joseph J. Cech, and Jeffrey B. Graham. "Temperature effects on the blood oxygen affinity in sharks." Fish Physiology and Biochemistry 44, no. 3 (March 5, 2018): 949–67. http://dx.doi.org/10.1007/s10695-018-0484-2.

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40

Block, Barbara A., and Francis G. Carey. "Warm brain and eye temperatures in sharks." Journal of Comparative Physiology B 156, no. 2 (1985): 229–36. http://dx.doi.org/10.1007/bf00695777.

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41

Dosay-Akbulut, Mine. "Specification of phylogenetic interrelations between skate-rays and sharks." Journal of Evolutionary Biochemistry and Physiology 42, no. 2 (March 2006): 128–33. http://dx.doi.org/10.1134/s0022093006020025.

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42

Pinte, Nicolas, Constance Coubris, Emma Jones, and Jérôme Mallefet. "Red and white muscle proportions and enzyme activities in mesopelagic sharks." Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 256 (October 2021): 110649. http://dx.doi.org/10.1016/j.cbpb.2021.110649.

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43

Brunnschweiler, J. M. "Tracking free-ranging sharks with hand-fed intra-gastric acoustic transmitters." Marine and Freshwater Behaviour and Physiology 42, no. 3 (May 2009): 201–9. http://dx.doi.org/10.1080/10236240903033519.

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44

Huber, Daniel R., Julien M. Claes, Jérôme Mallefet, and Anthony Herrel. "Is Extreme Bite Performance Associated with Extreme Morphologies in Sharks?" Physiological and Biochemical Zoology 82, no. 1 (January 2009): 20–28. http://dx.doi.org/10.1086/588177.

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45

Knight, K. "GLOWING SHARKS USE HORMONE ON/OFF SWITCHES." Journal of Experimental Biology 212, no. 22 (October 30, 2009): i—ii. http://dx.doi.org/10.1242/jeb.039727.

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46

Ferry-Graham, L. "Feeding kinematics of juvenile swellsharks, Cephaloscyllium ventriosum." Journal of Experimental Biology 200, no. 8 (April 1, 1997): 1255–69. http://dx.doi.org/10.1242/jeb.200.8.1255.

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To investigate how feeding behaviors change with prey size, high-speed video recording was used to examine the kinematics of prey capture and transport in 1-year-old swellsharks Cephaloscyllium ventriosum (Scyliorhinidae: Carchariniformes) feeding on two differently sized prey items. Prey capture in these sharks generally consisted of an initially ram-dominated capture bite, one or more manipulation bites, a holding phase during which the food was held in the teeth of the shark, and then suction-dominated prey transport. During initial capture and transport, most of the water taken in is forced back out of the mouth anteriorly rather than continuing posteriorly out through the gill openings. Dye experiments in which dye-perfused prey items were ingested by the sharks confirm this observation; distinct jets of colored water were video-taped as they were ejected from the mouth. Very late in prey transport, a bolus of water is ejected through the gill slits; however, by this time, the majority of water appears already to have exited the buccal cavity through the mouth. Such patterns were observed for sharks feeding on both small and large prey items. Although a basic pattern of prey capture and transport was regularly repeated among strikes, kinematic patterns during prey capture and transport were variable both within and among individuals, indicating that prey acquisition is not tightly controlled. However, the amount of variability was similar among prey sizes. In addition, there were no detectable changes in behavior due to prey item size. Ram-suction index values confirmed that similar capture modes were being utilized for both prey sizes.

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47

Ritter, Erich K., and Juerg M. Brunnschweiler. "Do Sharksuckers,Echeneis Naucrates, Induce Jump Behaviour in Blacktip Sharks,Carcharhinus Limbatus?" Marine and Freshwater Behaviour and Physiology 36, no. 2 (June 2003): 111–13. http://dx.doi.org/10.1080/1023624031000119584.

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48

Peach, Meredith B. "New microvillous cells with possible sensory function on the skin of sharks." Marine and Freshwater Behaviour and Physiology 38, no. 4 (December 2005): 275–79. http://dx.doi.org/10.1080/10236240500482416.

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49

Chin Lai, N., Nancy Dalton, Yin Yin Lai, Christopher Kwong, Randy Rasmussen, David Holts, and Jeffrey B. Graham. "A comparative echocardiographic assessment of ventricular function in five species of sharks." Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 137, no. 3 (March 2004): 505–21. http://dx.doi.org/10.1016/j.cbpb.2003.11.011.

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50

O’Shea, O. R., J. Mandelman, B. Talwar, and E. J. Brooks. "Novel observations of an opportunistic predation event by four apex predatory sharks." Marine and Freshwater Behaviour and Physiology 48, no. 5 (July 2015): 374–80. http://dx.doi.org/10.1080/10236244.2015.1054097.

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