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1
Bazúa-Durán, Carmen. "Differences in the whistle characteristics and repertoire of Bottlenose and Spinner Dolphins." Anais da Academia Brasileira de Ciências 76, no. 2 (June 2004): 386–92. http://dx.doi.org/10.1590/s0001-37652004000200030.
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Several methods have been used to compare the whistles produced by dolphins. The two methods used in this study are: (1) a classification of whistle contours in six categories (i.e. constant frequency, upsweep, downsweep, concave, convex, and sine) and (2) the extraction of frequency and time parameters from each whistle contour. Bottlenose Dolphin Tursiops truncatus whistles are described in the same way when comparing whistle contour distributions in each of the six categories and whistle frequency and time parameters using Discriminant Function Analysis. For Spinner Dolphin Stenella longirostris whistles, each method describes whistles differently. Several facts may explain these differences in describing dolphin whistles, such as a greater fluidity of Spinner Dolphin groups when compared to Bottlenose Dolphin groups, greater geographic variation in the whistles of Bottlenose Dolphins than in those of Spinner Dolphins, an average beginning frequency 16% lower than the average ending frequency in Spinner Dolphin whistles compared to a varied relationship for Bottlenose Dolphins, and stricter criteria used to define whistle contour categories in the study of Spinner Dolphin whistles than in the Bottlenose Dolphin whistle study.
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Nollens, Hendrik H., Linda G. Green, Diane Duke, Michael T. Walsh, Beth Chittick, Scott Gearhart, Paul A. Klein, and Elliott R. Jacobson. "Development and Validation of Monoclonal and Polyclonal Antibodies for the Detection of Immunoglobulin G of Bottlenose Dolphins (Tursiops Truncatus)." Journal of Veterinary Diagnostic Investigation 19, no. 5 (September 2007): 465–70. http://dx.doi.org/10.1177/104063870701900502.
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Antibodies directed against species-specific immunoglobulin G (IgG) have a broad range of applications in serologic and immunologic research and in the development of clinical assays. Validated anti-IgG antibodies for marine mammal species are in short supply. The objective of this study was to produce and validate antibodies with specificity for IgG of the common bottlenose dolphin ( Tursiops truncatus). Bottlenose dolphin IgG was purified using protein G. Two mouse monoclonal antibodies and a rabbit polyclonal antibody were developed from mice and rabbits immunized with bottlenose dolphin IgG. The specificity of the monoclonal antibodies and the polyclonal antibody for bottlenose dolphin IgG was first verified by Western blot analysis and enzyme-linked immunosorbent assay (ELISA). For further validation, both monoclonal antibodies and the polyclonal antibody were incorporated in an indirect ELISA for the detection of the immune response of bottlenose dolphins to a vaccine antigen. Three bottlenose dolphins were immunized with a commercial Erysipelothrix rhusiopathiae vaccine, and serial blood samples were collected from all dolphins for measurement of levels of circulating antibodies. Seroconversion was observed in all 3 dolphins by use of both monoclonal antibodies and the polyclonal antibody. Circulating antibodies were detectable as early as 6 days after immunization in 1 dolphin. Peak antibody levels were detected 14 days after the immunization. The ability to detect seroconversion in all 3 immunized bottlenose dolphins firmly establishes the specificity of the monoclonal antibodies and the polyclonal antibody for IgG of the common bottlenose dolphin.
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Estep, J. S., R. E. Baumgartner, F. Townsend, D. A. Pabst, W. A. Mclellan, A. Friedlaender, D. G. Dunn, and T. P. Lipscomb. "Malignant Seminoma with Metastasis, Sertoli Cell Tumor, and Pheochromocytoma in a Spotted Dolphin (Stenella frontalis) and Malignant Seminoma with Metastasis in a Bottlenose Dolphin (Tursiops truncatus)." Veterinary Pathology 42, no. 3 (May 2005): 357–59. http://dx.doi.org/10.1354/vp.42-3-357.
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Seminoma with metastasis was diagnosed in a spotted dolphin ( Stenella frontalis) and an Atlantic bottlenose dolphin ( Tursiops truncatus). Sertoli cell tumor and pheochromocytoma were also diagnosed in the spotted dolphin. The spotted and bottlenose dolphins were adult males that stranded and died on the coasts of northwest Florida and southeast North carolina, respectively. Neoplasia is infrequently reported in cetaceans. This is the first report of seminoma, Sertoli cell tumor, and pheochromocytoma in a dolphin, the first report of three distinct neoplasms in a dolphin, and one of the few reports of malignant neoplasia in dolphins.
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Bayas-Rea, Rosa de los Ángeles, Fernando Félix, and Rommel Montufar. "Genetic divergence and fine scale population structure of the common bottlenose dolphin (Tursiops truncatus, Montagu) found in the Gulf of Guayaquil, Ecuador." PeerJ 6 (April 9, 2018): e4589. http://dx.doi.org/10.7717/peerj.4589.
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The common bottlenose dolphin, Tursiops truncatus, is widely distributed along the western coast of South America. In Ecuador, a resident population of bottlenose dolphins inhabits the inner estuarine area of the Gulf of Guayaquil located in the southwestern part of the country and is under threat from different human activities in the area. Only one genetic study on South American common bottlenose dolphins has been carried out to date, and understanding genetic variation of wildlife populations, especially species that are identified as threatened, is crucial for defining conservation units and developing appropriate conservation strategies. In order to evaluate the evolutionary link of this population, we assessed the phylogenetic relationships, phylogeographic patterns, and population structure using mitochondrial DNA (mtDNA). The sampling comprised: (i) 31 skin samples collected from free-ranging dolphins at three locations in the Gulf of Guayaquil inner estuary, (ii) 38 samples from stranded dolphins available at the collection of the “Museo de Ballenas de Salinas,” (iii) 549 mtDNA control region (mtDNA CR) sequences from GenBank, and (iv) 66 concatenated sequences from 7-mtDNA regions (12S rRNA, 16S rRNA, NADH dehydrogenase subunit I–II, cytochrome oxidase I and II, cytochrome b, and CR) obtained from mitogenomes available in GenBank. Our analyses indicated population structure between both inner and outer estuary dolphin populations as well as with distinct populations of T. truncatus using mtDNA CR. Moreover, the inner estuary bottlenose dolphin (estuarine bottlenose dolphin) population exhibited lower levels of genetic diversity than the outer estuary dolphin population according to the mtDNA CR. Finally, the estuarine bottlenose dolphin population was genetically distinct from other T. truncatus populations based on mtDNA CR and 7-mtDNA regions. From these results, we suggest that the estuarine bottlenose dolphin population should be considered a distinct lineage. This dolphin population faces a variety of anthropogenic threats in this area; thus, we highlight its fragility and urge authorities to issue prompt management and conservation measures.
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Fruet, Pedro Friedrich, Camilah A. Zappes, Tatiana L. Bisi, Paulo César Simões-Lopes, Paula Laporta, Julio D. Loureiro, and Paulo André C. Flores. "Report of the Working Group on Interactions between Humans and Tursiops truncatus in the Southwest Atlantic Ocean." Latin American Journal of Aquatic Mammals 11, no. 1-2 (January 8, 2017): 79–98. http://dx.doi.org/10.5597/lajam00218.
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In this work we compiled the available information about humans and bottlenose dolphin interactions in the Southwest Atlantic Ocean (SWAO), including issues as historical direct takes, incidental captures in fisheries, positive interactions with fisheries, interactions of dolphins with tourism and boat traffic, habitat modification or degradation, and environmental pollution. The data compiled in this review demonstrated that coastal bottlenose dolphins are under anthropogenic pressure in the SWAO. Direct take of bottlenose dolphins in the wild does not appear to be an issue of conservation concern in the SWAO. Although the species is exposed to bioaccumulation of micropollutants, it is suggested that contamination level is lower when compared to bottlenose dolphins from other continents. Coastal works can impact bottlenose dolphin behavior and habitat use in a short-term, but those seem to be reversible when works stop. Bycatch occurs throughout the species distribution and seems to be occasional in Uruguayan and Argentinean waters, where there is evidence of a historic decline in dolphin sightings. In Brazil, bycatch is apparently low in the northeast and southeast coasts, but is frequent in certain areas of southern Brazil. Studies on the subject are scarce or preliminary and a great effort is still required to understand the real impact of human activities on bottlenose dolphins in the SWAO.
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Rossbach, Kelly A., and Denise L. Herzing. "Inshore and offshore bottlenose dolphin (Tursiops truncatus) communities distinguished by association patterns near Grand Bahama Island, Bahamas." Canadian Journal of Zoology 77, no. 4 (September 15, 1999): 581–92. http://dx.doi.org/10.1139/z99-018.
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Little is known about the behavior of offshore dolphin populations. Our purpose was to distinguish and describe stable social groups of bottlenose dolphins (Tursiops truncatus) between inshore and offshore West End, Grand Bahama Island (26°42'N, 79°00'W). Photoidentification was conducted from May to September, 1994 to 1996. A simple ratio index described association patterns between dolphins. Multidimensional scaling of association indices (n = 1711 dolphin pairs) distinguished two dolphin communities consisting of 28 dolphins (19 of known sex) found inshore and 15 dolphins (12 of known sex) found greater than or equal to 27 km offshore. Eight of the 15 offshore dolphins were opportunistically photographed in the same region between 1986 and 1990. The two communities were found at different water depths (Mann-Whitney U test, p < 0.01), over distinct bottom types (Kruskal-Wallis test, p < 0.01), and used different bottom-foraging strategies. Long-term site fidelity of up to 10 years and repeated dolphin associations of up to 8 years occurred greater than or equal to 27 km from shore. Dolphins sighted greater than or equal to 15 times averaged 48 associates (SD = 11, n = 28). A dolphin's closest associate was of the same gender 74% of the time. This study is the first to report long-term site fidelity and association patterns of bottlenose dolphins found far from shore.
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Díaz López, Bruno, and Julia Andrea Bernal Shirai. "Bottlenose dolphin (Tursiops truncatus) presence and incidental capture in a marine fish farm on the north-eastern coast of Sardinia (Italy)." Journal of the Marine Biological Association of the United Kingdom 87, no. 1 (February 2007): 113–17. http://dx.doi.org/10.1017/s0025315407054215.
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On the north-eastern coast of Sardinia, from November 2004 to January 2006, the first attempt in the Mediterranean basin to obtain information on encounter rate, group size and incidental capture of bottlenose dolphins in a marine fish farm was assessed, combining direct observations from fish farm boats with photo-identification studies. During 15 months of research, 79 d (65.3% of the total monitored days) were spent in direct observation of 146 groups of bottlenose dolphins around the fish farm cages. There was a peak in bottlenose dolphin presence during winter. Photographs were taken in the fish farm area during 79 encounters on 61 different days (totalling 34 marked individuals). The regular occurrence of some dolphins suggests individual preferences for the fish farm area. The incidental bottlenose dolphin capture observed in large, loose predator nets (1 dolphin per month) is cause for concern, as it is questionable whether or not the bottlenose dolphins in the area can sustain incidental capture of this magnitude. The information gained from this study shows the necessity for further regulations to be established, both in the use of predator nets and management of marine fish farms.
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Miller, LJ, J. Mellen, T. Greer, and SA Kuczaj II. "The effects of education programmes on Atlantic bottlenose dolphin (Tursiops truncatus) behaviour." Animal Welfare 20, no. 2 (May 2011): 159–72. http://dx.doi.org/10.1017/s0962728600002645.
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AbstractAtlantic bottlenose dolphins (Tursiops trucatus) are found in zoos and aquaria throughout the world. As the number of facilities with dolphin shows and interaction programmes increases, it becomes more important to understand the effects of such programmes on dolphin behaviour. The present study examined the short-term effects of dolphin shows and interaction programmes on the behaviour of Atlantic bottlenose dolphins at six facilities. Rates of affiliative behaviour, aggressive behaviour, repetitive behaviour and percentage of time spent socialising were found to be unrelated to dolphin shows or interaction programmes. Additionally, dolphins exhibited higher rates of behavioural diversity, diversity of swimming style, and play behaviour following shows and interaction programmes. These results suggest that dolphin shows and interaction programmes can be an important part of an enrichment programme for dolphins in zoological institutions. However, individual differences should be considered when animals participate in these types of programmes.
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Díaz López, Bruno, Julia Andrea Bernal Shirai, Alberto Bilbao Prieto, and Paula Méndez Fernández. "Diving activity of a solitary wild free ranging bottlenose dolphin (Tursiops truncatus)." Journal of the Marine Biological Association of the United Kingdom 88, no. 6 (March 25, 2008): 1153–57. http://dx.doi.org/10.1017/s0025315408000921.
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Solitary wild bottlenose dolphins and man frequenting the same small areas makes boat interaction more or less inevitable. Here we provide the first quantified data about solitary bottlenose dolphin diving behaviour in the presence and absence of boats. Over 110 hours were spent observing a solitary bottlenose dolphin within a 6 km2 bay on the north-western coast of Spain from April to August 2005. A generalized linear mixed model explaining 77.3% of the variability of duration of dives indicated that the animal did not vary its diving activity in function of the presence of boats. However, the length of dives was related with the behavioural events prior to dive. Dolphin activity was characterized by mean dive intervals (mean = 62.6 seconds) related to a predominance of foraging behaviour. Because of the frequent presence of boats and the manner in which they moved, the dolphin may have become accustomed to their presence. The data reported here could be used to implement precautionary management proposals that take into account the potential effects of boat presence on bottlenose dolphins.
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Wright, Katherine A. "Decreased ability to acquire food of a captive deaf dolphin (Tursiops truncatus): Slower reaction times and lower success rates." SURG Journal 4, no. 2 (March 11, 2011): 63–70. http://dx.doi.org/10.21083/surg.v4i2.1253.
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Oceanic anthropogenic noise, such as naval sonar, can cause temporary hearing loss in cetaceans, but it is not known to what extent hearing loss affects cetacean behaviours such as feeding. This study used a captive deaf Atlantic bottlenose dolphin (Tursiops truncatus) to test the hypothesis that hearing loss would decrease a dolphin’s ability to acquire food by preventing echolocation (using echoes to locate fish). Reaction time (time to acquire dropped fish) and success rate (percentage of successfully acquired fish) were measured for the deaf dolphin and for two dolphins with no known hearing disabilities at Dolphins Plus in Florida in May 2009. The deaf dolphin had a significantly slower mean reaction time and a significantly lower mean success rate than those of the two other dolphins. A hydrophone suggested that the deaf dolphin could not echolocate, and thus relied mainly on vision. The results illustrate that hearing loss can negatively affect a dolphin’s ability to acquire food. Therefore, sources and effects of dolphin hearing loss require further investigation in order to provide targets for anthropogenic noise levels.
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Vermeulen, Els. "Intertidal habitat use of bottlenose dolphins (Tursiops truncatus) in Bahía San Antonio, Argentina." Journal of the Marine Biological Association of the United Kingdom 98, no. 5 (May 30, 2017): 1109–18. http://dx.doi.org/10.1017/s0025315417000856.
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Very little information is available on bottlenose dolphin (Tursiops truncatus) habitat use in the South-western Atlantic. It is, however, essential in understanding their ecology and to improve conservation management. In this study, habitat use of bottlenose dolphins was examined in Bahía San Antonio, an area frequented by the species. Given the large tidal amplitude and extended intertidal zone in this bay, special focus was given to the intertidal vs subtidal habitat use patterns. Bottlenose dolphins were observed in only half of the surveyed area, with on average 1 dolphin group encountered per 100 km surveyed. All dolphin groups were seen in shallow waters <10 m deep. GLM analyses showed that especially during high tide, depth had an important effect on the dolphin encounter rate, with most dolphin groups encountered in the intertidal zone. While in the intertidal zone, most dolphin groups were observed to be engaged in surface feeding activities. The presented data indicate dolphins remained in shallow waters, and moved to the intertidal zone during high tide where they appear to find feeding opportunities. This information is believed to be of high value in understanding this population's ecological needs, and essential when aiming to improve marine conservation efforts at times of increased anthropogenic pressures in the area.
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Hawkins, Elizabeth R., Mia Gustavsson, Lara Pogson-Manning, Heather Pheloung, and Christian Jaehnichen. "Prevalence of Skin Lesions and Injuries in Australian Humpback Dolphins (Sousa sahulensis) and Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) in Moreton Bay, Queensland." Aquatic Mammals 48, no. 4 (July 15, 2022): 297–313. http://dx.doi.org/10.1578/am.48.4.2022.297.
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Coastal dolphin populations are highly vulnerable due to their proximity to major urban centres and exposure to cumulative threats from anthropogenic activities. As bioindicators of environmental condition, it is crucial to understand and monitor the health of these coastal dolphin populations. Visual assessments of skin lesions on dolphins can provide useful insights into the health of these populations and exposure to environmental stressors. We examined the prevalence of skin lesions in Australian humpback dolphins (Sousa sahulensis) and Indo-Pacific bottlenose dolphins (Tursiops aduncus) of different age classes inhabiting the near-urban embayment of Moreton Bay, Queensland. The prevalence and extent of nontraumatic and traumatic skin lesions on individual dolphins were assessed using photographs taken during 103 boat-based surveys completed between 2014 and 2016. A total of 15 primary skin lesion categories were identified from 126 humpback and 100 bottlenose dolphins. Differences in the prevalence of skin lesions were evident between age classes and species. Nontraumatic skin lesions were prevalent in 48.4% of the humpback and 61.0% of the bottlenose dolphins. Comparatively, traumatic lesions were evident in almost all humpback (92.3%) and bottlenose (99.0%) dolphins. Anthropogenic-related injuries from entanglement in fishing gear and vessel strikes were substantial and significantly differed between species (p < 0.05). Injuries from fishing and vessel activities affected 11.0% of humpback dolphins and 30.0% of bottlenose dolphins, suggesting that these activities pose a major threat to these populations. Findings from this study provide an important baseline to inform ongoing health monitoring and conservation efforts of these vulnerable dolphin populations inhabiting a near-urban embayment.
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Ascheri, Davide, Elena Fontanesi, Marco Ballardini, Barbara Nani, and Jessica Alessi. "Occurrence, site fidelity, and abundance of bottlenose dolphins (Tursiops truncatus) in the Western Ligurian Sea." J. Cetacean Res. Manage. 23, no. 1 (December 22, 2022): 191–204. http://dx.doi.org/10.47536/jcrm.v23i1.365.
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This study represents the first complete assessment of the population dynamics and residency of common bottlenose dolphins in the Western Ligurian Sea, an area where bottlenose dolphin sightings have been rare in the past. Despite being greatly affected by human pressure, information about this population is poor and sporadic. The study took place from April 2018 to December 2020. One hundred and seventy‐one dedicated boat surveys were performed year‐round resulting in 95 sightings, and 123 individuals were identified through mark‐recapture photo‐identification techniques. Dolphins were found to be present year‐round. Most of the animals (79) used the area sporadically and only 19.5% of the dolphins (24) were seen regularly. Bottlenose dolphin abundance was estimated at 248 using open POPAN population models (CI 95% = 217–284). These results help fill a knowledge gap by highlighting the regular presence of bottlenose dolphins in the study area. Moreover, they represent a baseline for future studies investigating abundance trends and the conservation status of this population
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Fury, Christine A., and Peter L. Harrison. "Abundance, site fidelity and range patterns of Indo-Pacific bottlenose dolphins (Tursiops aduncus) in two Australian subtropical estuaries." Marine and Freshwater Research 59, no. 11 (2008): 1015. http://dx.doi.org/10.1071/mf08109.
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Bottlenose dolphins are widely studied in marine habitats, but information on estuarine populations is very limited. The present study provides the first published data on bottlenose dolphins in Australian estuaries. Abundance estimates, site fidelity and individual ranging patterns were examined over a 3-year period for Indo-Pacific bottlenose dolphins (Tursiops aduncus) inhabiting the Clarence River (CR) and Richmond River (RR) estuaries in northern New South Wales, Australia. Mark–recapture analyses estimated 71 (62–81 95% CI) dolphins utilised the CR whereas 34 (19–49 95% CI) used the RR. Differences in site fidelity were observed between the estuaries, with 60% and 37% of identified dolphins determined as residents, 26% and 21% as occasional visitors and 14% and 42% as transients for the CR and RR respectively. Resource partitioning was apparent in both estuaries with the mean distance resident dolphins were found upstream from the river mouth being greater than occasional visitors and transients. The Clarence River sustains a larger, predominantly resident dolphin community compared with the Richmond River, which supports a relatively small dolphin community with lower site fidelity. Management of future increased anthropogenic disturbances is needed to ensure the long-term survival of these dolphin populations.
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Díaz López, Bruno. "The bottlenose dolphin Tursiops truncatus foraging around a fish farm: Effects of prey abundance on dolphins’ behavior." Current Zoology 55, no. 4 (August 1, 2009): 243–48. http://dx.doi.org/10.1093/czoolo/55.4.243.
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Abstract The extent to which prey abundance influences both bottlenose dolphin foraging behavior and group size in the presence of human activities has not previously been studied. The primary aim of this study was to identify and quantify how wild bottlenose dolphins respond, individually and as groups, to the relative abundance of prey around a fish farm. Detailed views of dolphins’ behavior were obtained by focal following individual animals whilst simultaneously collecting surface and underwater behavioral data. A total of 2150 dive intervals were analyzed, corresponding to 342 focal samples, lasting over 34 hours. Bottlenose dolphins remained submerged for a mean duration of 46.4 seconds and a maximum of 249 seconds. This study provides the first quantified data on bottlenose dolphin diving behavior in a marine fin-fish farm area. This study’s results indicate that within a fish farm area used intensively by bottlenose dolphins for feeding, dolphins did not modify dive duration. Additionally, underwater observations confirmed that dolphins find it easier to exploit a concentrated food source and it appears that hunting tactic and not group size plays an important role during feeding activities. Thus, bottlenose dolphins appear capable of modifying their hunting tactics according to the abundance of prey. When top predators display behavioral responses to activities not directed at them, the task of studying all possible effects of human activities can become even more challenging.
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Olson, Grace L., Stephanie H. Stack, Abigail F. Machernis, Florence A. Sullivan, and Jens J. Currie. "Mapping the Exposure of Pantropical Spotted Dolphins and Common Bottlenose Dolphins to Different Categories of Vessel Traffic in Maui Nui, Hawai‘i." Aquatic Mammals 48, no. 2 (March 15, 2022): 167–81. http://dx.doi.org/10.1578/am.48.2.2022.167.
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The increase and diversification of vessel traffic worldwide has resulted in a variety of known disturbances to dolphins. As a remote island chain, the Hawaiian Islands rely heavily on the marine environment for transportation, recreation, and fishing that aggregates into significant levels of vessel traffic. Given the known presence of dolphins in this region, there is a gap in knowledge regarding the relative exposure risk that vessel traffic poses to island-associated dolphin populations in Hawai‘i. This research identified the spatial distribution of pantropical spotted dolphins (Stenella attenuata) and common bottlenose dolphins (Tursiops truncatus) and determined the extent of their overlap with various categories of vessel traffic in Maui Nui, Hawai‘i. Species distribution was determined using kernel density estimates based on sighting data from 50 spotted dolphin sightings and 75 bottlenose dolphin sightings collected from 2013 to 2018. A combination of vessel GPS and Automatic Identification Systems (AIS) vessel tracks were used to quantify vessel traffic within the study area, resulting in 22,464 vessel tracks that were subsequently compiled into categories for analysis from 2014 to 2017. Risk of vessel exposure between vessels and dolphins, or co-occurrence, was determined by calculating the product of predicted dolphin density and predicted vessel density. Both species were exposed to vessel traffic risk over 100% of their distribution, but their highest exposure risk varied spatially, with high risk defined as > 0.25 on a normalized scale of low (0) to high (1) risk. The highest vessel exposure risk for spotted dolphins occurred in deeper, offshore waters, while the highest risk for bottlenose dolphins was in shallow, coastal waters. The vessel categories with the largest area of high risk to spotted dolphins were tour vessel and commercial fishing vessel traffic, while commercial transportation traffic had the highest exposure risk for bottlenose dolphins. This article provides baseline information for understanding the vulnerability of two island-associated dolphin populations to the threat of vessel traffic and highlights the differences in relative exposure risk based on species and vessel categories.
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Domit, Camila, Paula Laporta, Camilah A. Zappes, Liliane Lodi, Lilian S. Hoffmann, Rodrigo Genoves, Pedro Friedrich Fruet, and Alexandre F. Azevedo. "Report of the Working Group on the Behavioral Ecology of bottlenose dolphins in the Southwest Atlantic Ocean." Latin American Journal of Aquatic Mammals 11, no. 1-2 (January 8, 2017): 106–20. http://dx.doi.org/10.5597/lajam00220.
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In this report, we present a compilation of the behavioral patterns of bottlenose dolphins and social structure throughout the Southwest Atlantic Ocean. We have compiled and summarized available data concerning: (i) behavioral activities (states and events), (ii) social structures (group size and composition), (iii) acoustic behavior and (iv) intra and interspecific interactions of bottlenose dolphin populations throughout the SWAO, from northern Brazil to southern Argentina. Lack of systematic and standardized methodologies for data collection precludes robust data analyses in respect of bottlenose dolphin behavior. Available information suggests that the studied populations presented weak intra-population associations and that coastal individuals tend to form smaller groups than their oceanic counterparts. Bottlenose dolphins from SWAO produce stylized whistles in which the acoustic parameters are similar to published ranges around the world and some results indicate significant local inter-population variation in the acoustic parameters of the whistles. Data of intra and interspecific interactions of bottlenose dolphins in the SWAO are scarce and therefore do not fully allow a comprehensive analysis of the situational contexts.
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Biancani, Barbara, Livio Galosi, Adolfo Maria Tambella, Sara Berardi, Lucia Biagini, Subeide Mari, and Giacomo Rossi. "Comparative Study of the Gastric Mucosa of Risso’s Dolphin (Grampus griseus) and Bottlenose Dolphin (Tursiops truncatus): A Key to Manage the Diet in Captive Conditions." Veterinary Sciences 9, no. 10 (October 16, 2022): 571. http://dx.doi.org/10.3390/vetsci9100571.
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To histologically evaluate the gastric compartments of Risso’s (Grampus griseus) and bottlenose dolphins (Tursiops truncatus) and provide suggestions for the diet of Risso’s dolphins in captivity, we examined 12 stomachs from both species. While slight differences in keratinization were observed in the forestomach, significant differences came to light in the second stomach’s mucosa. At this level, in Risso’s dolphin, the principal cells are markedly reduced in size and located externally to the parietal cells, not interspersed between them, compared to bottlenose dolphins; differences were also observed in the structure and concentration of the parietal and principal cells of the gastric body glands (p < 0.0001). The quantitative results of G- and D-cell counts in the gastric mucosa show a clear difference, with a higher concentration of G cells in the mucosa of Risso’s dolphin (t = 7.334; p < 0.0001) and a higher level of D cells in bottlenose dolphin mucosa (t = 3.123; p = 0.0049). These results suggest that parietal cells undergo greater stimulation by gastrin produced by G cells, with greater acid secretion in G. griseus. Further studies are needed to understand whether an inappropriate diet could lead to severe clinical signs due to gastric acidity in Risso’s dolphin.
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Díaz-Santana, Pablo, Antonio Fernández, Josue Díaz-Delgado, Ana Isabel Vela, Lucas Domínguez, Cristian Suárez-Santana, Raquel Puig-Lozano, Carolina Fernández-Maldonado, Eva Sierra, and Manuel Arbelo. "Nocardiosis in Free-Ranging Cetaceans from the Central-Eastern Atlantic Ocean and Contiguous Mediterranean Sea." Animals 12, no. 4 (February 11, 2022): 434. http://dx.doi.org/10.3390/ani12040434.
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We report the pathologic features of nocardiosis in five free-ranging delphinids from the Canary Islands and Andalusia, namely four striped dolphins (Stenella coerulealba) and one bottlenose dolphin (Tursiops truncatus). All animals had a multiorgan (disseminated) pattern of infection involving suppurative to pyogranulomatous and thromboembolic lesions in two or more organs. Most affected organs were (by decreasing order) lung, pulmonary lymph nodes, liver, kidney, adrenal glands, and central nervous system. Typical intralesional and intravascular branched and filamentous bacteria were highlighted by Grocott’s methenamine silver and Gram stains. Bacterial analysis including 16S rRNA gene sequencing identified Nocardia farcinica in two striped dolphins and Nocardia otitidiscaviarum in one striped dolphin and the bottlenose dolphin. All dolphins tested (n = 4) for cetacean morbillivirus were negative; one dolphin had concurrent cutaneous herpesvirosis. These results provide the first record of N. otitidiscaviarum in cetaceans, the first account of N. farcinica in free-ranging dolphins, and confirmation of nocardiosis in central eastern Atlantic Ocean. These results expand the known geographic range of nocardiosis in cetaceans.
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Affinito, Flavio, Cristobal Olaya Meza, Aylin Akkaya Bas, Deborah Brill, Guy Whittaker, and Lasse Capel. "On the behaviour of an under-studied population of bottlenose dolphins in the Southern Adriatic Sea." Journal of the Marine Biological Association of the United Kingdom 99, no. 4 (October 22, 2018): 1017–23. http://dx.doi.org/10.1017/s0025315418000772.
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AbstractPerhaps the world's best-known cetacean, the bottlenose dolphin shows considerable variation in behaviour between and within populations in relation to differences in natural and anthropogenic conditions. Drivers of behavioural variation need to be identified to understand the dynamics of wild dolphin populations. Little research has been published on the bottlenose dolphin population found in the Southern Adriatic Sea. Using a set of spatial, temporal and social predictors, we aimed to investigate what variables are related to the behaviour of an under-studied population of bottlenose dolphins along the coastline of Montenegro. We present the results of a year-long study monitoring the behaviour of bottlenose dolphins along coastal Montenegro. We considered the effect of topography, seasonality and group size. A large proportion of travelling (55%) small groups (mean 4, range 1–9) in shallow waters (<50 m) was observed. We showed that seasonality alone explained behaviour best, with surface-feeding and socializing-resting increasing in autumn and winter. Group size was found to be a result of behavioural choice. We suggest seasonal changes in environmental conditions and anthropogenic pressure may explain the recorded behavioural pattern. This research points to the necessity of increased collaboration in the region to help understand complex patterns in behaviour and habitat use of local dolphin populations if effective conservation measures are to be developed.
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Moura, Jailson, Davi Castro Tavares, Helio K. C. Secco, and Salvatore Siciliano. "Bottlenose dolphins (Tursiops truncatus, Montagu 1821) in central-northern coast of Rio de Janeiro State, Brazil: stranding patterns and insights into feeding habits." Latin American Journal of Aquatic Mammals 11, no. 1-2 (January 8, 2017): 191–98. http://dx.doi.org/10.5597/00228.
Full textAbstract:
The bottlenose dolphin (Tursiops truncatus) may be one of the best known dolphin species worldwide, principally due to its coastal distribution in many regions. However, few studies about ecology, biology and threats have been conducted on the Brazilian coast. The aim of the present work is to analyze the stranding pattern and stomach contents of bottlenose dolphins in the central-north coast of the Rio de Janeiro State, from Saquarema to São Francisco de Itabapoana (~300km of coast line). Forty nine stranding events were recorded through regular beach surveys from 1999 to 2012 and also through access to previous published studies conducted since 1984. The strandings were distributed throughout the study area, but there was a trend of occurrence in the extreme southern and northern regions. Nine specimens showed evidence of accidental mortality in fishing nets. The strandings were more frequently recorded during autumn and winter (χ2; p < 0.05). Male bottlenose dolphins stranded more often than females, showing significant differences in this relationship (χ2; p < 0.05). Most stranded dolphins were classified as adults (> 230cm of body length) (χ2; p < 0.05). The body length varied from 106 to 335cm. Four prey species were found in the stomach contents from the three specimens of bottlenose dolphin analyzed. The most representative prey species was the cutlassfish (Trichiurus lepturus). This study showed that bottlenose dolphins are frequently found dead along the Rio de Janeiro State where they feed mainly on coastal fish. Future studies need to be conducted to improve the knowledge on this poorly known cetacean in Brazil.
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Cuvertoret-Sanz, M., C. López-Figueroa, A. O’Byrne, A. Canturri, B. Martí-Garcia, E. Pintado, L. Pérez, et al. "Causes of cetacean stranding and death on the Catalonian coast (western Mediterranean Sea), 2012-2019." Diseases of Aquatic Organisms 142 (December 17, 2020): 239–53. http://dx.doi.org/10.3354/dao03550.
Full textAbstract:
The causes of cetacean stranding and death along the Catalan coast between 2012 and 2019 were systematically investigated. Necropsies and detailed pathological investigations were performed on 89 well-preserved stranded cetaceans, including 72 striped dolphins Stenella coeruleoalba, 9 Risso’s dolphins Grampus griseus, 5 bottlenose dolphins Tursiops truncatus, 1 common dolphin Delphinus delphis, 1 Cuvier’s beaked whale Ziphius cavirostris and 1 fin whale Balaenoptera physalus. The cause of death was determined for 89.9% of the stranded cetaceans. Fisheries interaction was the most frequent cause of death in striped dolphins (27.8%) and bottlenose dolphins (60%). Cetacean morbillivirus (CeMV) was detected on the Catalan coast from 2016 to 2017, causing systemic disease and death in 8 of the 72 (11.1%) striped dolphins. Chronic CeMV infection of the central nervous system was observed from 2018-2019 in a further 5 striped dolphins. Thus, acute and chronic CeMV disease caused mortality in 18% of striped dolphins and 14.6% of all 89 cetaceans. Brucella ceti was isolated in 6 striped dolphins and 1 bottlenose dolphin with typical brucellosis lesions and in 1 striped dolphin with systemic CeMV. Sinusitis due to severe infestation by the nematode parasite Crassicauda grampicola caused the death of 4 out of 6 adult Risso’s dolphins. Maternal separation, in some cases complicated with septicemia, was a frequent cause of death in 13 of 14 calves. Other less common causes of death were encephalomalacia of unknown origin, septicemia, peritonitis due to gastric perforation by parasites and hepatitis caused by Sarcocystis spp.
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Schultz, Kenneth W., and Peter J. Corkeron. "Interspecific differences in whistles produced by inshore dolphins in Moreton Bay, Queensland, Australia." Canadian Journal of Zoology 72, no. 6 (June 1, 1994): 1061–68. http://dx.doi.org/10.1139/z94-143.
Full textAbstract:
The sounds produced by bottlenose dolphins, Tursiops truncatus, and Indo-Pacific humpback dolphins, Sousa chinensis, were recorded on 11 days from 3 April to 13 August 1990 in Moreton Bay, eastern Australia. Twelve hours and 34 minutes of sound were recorded. The physical structure of whistles was described using a variable for duration and seven variables for frequency. Data were subjected to principal components analysis (PCA) and canonical discriminant analysis (CDA). PCA demonstrated the range of whistle contours recorded. CDA demonstrated differences in the whistles between species. Humpback dolphin whistles differed in shape (frequency modulation) and were generally of shorter duration and higher overall frequency than those of bottlenose dolphin whistles.
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Savenko, Oksana. "The first record of a piebald common bottlenose dolphin (Tursiops truncatus) in offshore waters of the north-western Black Sea." Theriologia Ukrainica 2020, no. 19 (August 27, 2020): 103–7. http://dx.doi.org/10.15407/tu1911.
Full textAbstract:
Piebaldism is one of three types of hypopigmentation of animals, when some areas on the skin have no pigments. Anomalously white cetaceans are rare, although they have been reported in more than 20 different cetacean species, including the common bottlenose dolphin, which in the Black Sea is recognized as an endangered endemic subspecies — the Black Sea bottlenose dolphin (Tursiops truncatus ponticus Barabash-Nikiforov, 1940). Its main habitat in the north-western Black Sea region is the coastal waters, however, these dolphins also occur offshore. Thirty cases of anomalously white bottlenose dolphins have been reported from the Black Sea, which were unevenly distributed, and only a few sightings have been reported from the north-western Black Sea. Cetacean observations were conducted in the Ukrainian part of the north-western Black Sea waters in April 2017, onboard the research vessel "Auguste Piccard". All encountered cetaceans were photographed, and individual distinctiveness of dorsal fin images was used for their photo-identification. On 13 April 2017, four groups of up to four individuals of bottlenose dolphins were encountered in the same area at a distance of 61 km south of Odesa (34 km from the nearest coast). The depth at the observation site was about 20 m. The initially observed type of dolphins’ behavior was feeding. However, two groups changed their behavior and followed the vessel by 5–6 individuals for approximately 18 minutes. The joint group consisted of adults and one juvenile individual. Among the adults, there was one piebald specimen with white patches on its dorsal fin, peduncle, and tail fluke. The piebald dolphin was photographed and photo-identified. Our research has shown that piebald Black sea bottlenose dolphins occur not only in the coastal waters, but also in offshore waters of the north-western Black Sea. However, the frequency of such hypopigmentation in local populations remains unknown. Further intensive photo-identification and genetic sampling of local stocks of the Black Sea bottlenose dolphins are necessary for the assessment of their population genetic structure and its divergence.
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Balmer, B. C., R. S. Wells, S. M. Nowacek, D. P. Nowacek, L. H. Schwacke, D. A. Mclellan, F. S. Scharf, et al. "Seasonal abundance and distribution patterns of common bottlenose dolphins (Tursiops truncatus) near St. Joseph Bay, Florida, USA." J. Cetacean Res. Manage. 10, no. 2 (February 15, 2023): 157–67. http://dx.doi.org/10.47536/jcrm.v10i2.650.
Full textAbstract:
Three unusual mortalities events involving bottlenose dolphins (Tursiops truncatus Montagu 1821) occurred along Florida’s northern Gulf of Mexico coast between 1999 and 2006. The causes of these events, in which over 300 bottlenose dolphins are known to have died, are still under investigation. The impact of these mortality events cannot be fully evaluated, because little prior information on bottlenose dolphin abundance and distribution patterns exist in this region. Thus, the goals of this study were to estimate seasonal abundance, develop site-fidelity indices, and describe distribution patterns of bottlenose dolphins in St. Joseph Bay, Gulf County, Florida, USA. This study site was chosen because it was impacted by all three unusual mortality events and was the geographic focus of the 2004 event. Mark-recapture photo-identification surveys were conducted across multiple seasons from February 2005 through July 2007. Site-fidelity indices were calculated for each identifiable dolphin based upon all photo-ID efforts undertaken in the area. Distribution patterns were investigated by short-term (12-94 days) radio-tracking of tagged individuals across seasons (April-July, n=9; July-October, n=15). Mark-recapture closed and robust abundance estimates, as well as site-fidelity indices suggest that St. Joseph Bay supports a resident community of 78-152 bottlenose dolphins. During spring and autumn, this region experiences an influx of dolphins, as demonstrated by closed and robust abundance estimates of 313-410 and 237-340, respectively. These results are supported by the distribution patterns of radio-tagged individuals. Individuals tagged in summer tended to stay within or near St. Joseph Bay, whereas two individuals tagged in spring ranged more than 40km from the study site. This study provides the first detailed examination of bottlenose dolphin abundance and distribution patterns for this region of the northern Gulf coast of Florida. These results suggest that unusual mortality events probably had, and will in the future have, seasonally variable effects on bottlenose dolphins in St. Joseph Bay. Future mortality events that occur during the summer and winter in St. Joseph Bay may predominantly affect resident individuals, while those that occur during the spring and autumn will probably affect both residents and seasonal visitors.
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Whitt, Amy D., James A. Powell, Alec G. Richardson, and Jennifer R. Bosyk. "Abundance and distribution of marine mammals in nearshore waters off New Jersey, USA." J. Cetacean Res. Manage. 15, no. 1 (February 1, 2023): 45–59. http://dx.doi.org/10.47536/jcrm.v15i1.514.
Full textAbstract:
Marine mammal abundance and distribution in New Jersey’s nearshore waters are not well known due to limited dedicated studies. The first yearround systematic surveys were conducted to determine the spatial/temporal distribution and estimate the abundance of marine mammals in this region prior to wind power development. Eight marine mammal species were observed: North Atlantic right whale (Eubalaena glacialis), humpback whale (Megaptera novaeangliae), minke whale (Balaenoptera acutorostrata), fin whale (Balaenoptera physalus), bottlenose dolphin (Tursiops truncatus), common dolphin (Delphinus delphis), harbour porpoise (Phocoena phocoena) and harbour seal (Phoca vitulina). Results indicate clear seasonal patterns in distribution and abundance. The fin whale, humpback whale and bottlenose dolphin were sighted during all seasons. The abundance of large whales in the study area was relatively low while the abundance of dolphin and porpoise species was high and largely seasonal. The bottlenose dolphin was the most abundant species; however, abundance was high only during spring and summer. Common dolphins and harbour porpoises were common in the study area during winter and spring. These baseline data will be used to assess potential environmental impacts of the construction and operation of offshore wind power facilities in this region.
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Bauer, Gordon B., and Christine M. Johnson. "Trained Motor Imitation by Bottlenose Dolphins (Tursiops Truncatus)." Perceptual and Motor Skills 79, no. 3 (December 1994): 1307–15. http://dx.doi.org/10.2466/pms.1994.79.3.1307.
Full textAbstract:
Each of two bottlenose dolphins, Tursiops truncatus, was trained to mimic a set of behaviors on command. They were tested on transfer of the mimic command to a set of familiar behaviors which they had not previously been commanded to mimic. They were similarly tested on two novel behaviors. One dolphin demonstrated complete mimicry of 5 of 11 familiar behaviors; the other dolphin mimicked 1 of 9 behaviors. None of the mimicked behaviors was exhibited to an inappropriate model, suggesting that performance was not due to chance. Neither dolphin imitated the novel behaviors.
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Hurst, Brianna, and Dara Orbach. "Salinity Affects Wound Healing in Wild Common Bottlenose Dolphins (Tursiops truncatus)." American Journal of Undergraduate Research 19, no. 1 (July 12, 2022): 23–29. http://dx.doi.org/10.33697/ajur.2022.056.
Full textAbstract:
Dolphins are often individually identified by unique naturally-acquired markings. Identification becomes difficult when markings heal, or new scars appear. As salt accelerates wound healing in many organisms, the diminishment of scars on common bottlenose dolphins (Tursiops truncatus) residing in varying natural salinities was determined. South Texas contains the only hypersaline lagoon in the USA, located adjacent to hyposaline waters, with genetically distinct populations of dolphins in the two environments. Photographs of dolphin dorsal fins were collected, and scar stability over time was determined and compared by measuring changes in the relative lengths and surfaces of scars. All scars on dolphins in the hypersaline lagoon completely diminished between three to six years, while scars on dolphins in the hyposaline bay ranged in the amount of fading between three to six years. Data from this case study indicate that high salinity may increase the healing speed of wounds on common bottlenose dolphins compared to low salinity, although a larger sample size is needed for robust statistical comparison. Scar diminishment is an important consideration in determining the temporal reliability of photo identification. KEYWORDS: Bottlenose dolphin; Corpus Christi Bay; healing; hypersaline; Laguna Madre; photo-identification; salinity; scar
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Allen, Simon J., Daniele D. Cagnazzi, Amanda J. Hodgson, Neil R. Loneragan, and Lars Bejder. "Tropical inshore dolphins of north-western Australia: Unknown populations in a rapidly changing region." Pacific Conservation Biology 18, no. 1 (2012): 56. http://dx.doi.org/10.1071/pc120056.
Full textAbstract:
Australian Snubfin Orcaella heinsohni, Indo-Pacific Humpback Sousa chinensis and Indo-Pacific Bottlenose Dolphins Tursiops aduncus inhabit Australia’s tropical north-western coastline, a region undergoing extensive port development associated with the massive expansion of the oil, gas and mining industries. The current lack of data on dolphin population sizes or trends precludes impact assessments of developments on these protected species. Furthermore, the Western Australian and Commonwealth Government conservation listings of tropical inshore dolphins do not reflect their international listings. From April to July, 2010, we conducted ad hoc boat-based surveys (n=55) of inshore delphinids at seven sites across north-western Australia from Coral Bay in the south (23.1°S: 113.8°E) to Cable Beach in the north (17.9°S: 122.2°E). We documented the locations of these three species from which we obtained photoidentification and biopsy data, as well as reports of Australian Snubfin Dolphin sightings from researchers and community groups. The data from this limited field effort confirm that Indo-Pacific Humpback and Indo-Pacific Bottlenose Dolphins occur in the waters adjacent to each north-western Australian urban centre and show that the range of the Australian Snubfin Dolphin extends considerably further south-west than previously reported. Given the scale of coastal developments and the vulnerability of isolated cetacean populations to fragmentation or extirpation, assessments of the viability of dolphin populations are required. Our data suggest that the Australian Snubfin, Indo-Pacific Humpback and Indo-Pacific Bottlenose Dolphins need to be considered as likely to be impacted by coastal developments across north-western Australia.
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Rodriguez, Lauren Kelly, Amber D. Fandel, Benjamin R. Colbert, Jamie C. Testa, and Helen Bailey. "Spatial and temporal variation in the occurrence of bottlenose dolphins in the Chesapeake Bay, USA, using citizen science sighting data." PLOS ONE 16, no. 5 (May 18, 2021): e0251637. http://dx.doi.org/10.1371/journal.pone.0251637.
Full textAbstract:
Bottlenose dolphins (Tursiops truncatus) are migratory marine mammals that live in both open-ocean and coastal habitats. Although widely studied, little is known about their occurrence patterns in the highly urbanized estuary of the Chesapeake Bay, USA. The goal of this study was to establish the spatial and temporal distribution of bottlenose dolphins throughout this large estuarine system and use statistical modeling techniques to determine how their distribution relates to environmental factors. Three years (April-October 2017–2019) of dolphin sighting reports from a citizen-science database, Chesapeake DolphinWatch, were analyzed. The dolphins had a distinct temporal pattern, most commonly sighted during summer months, peaking in July. This pattern of observed occurrence was confirmed with systematic, passive acoustic detections of dolphin echolocation clicks from local hydrophones. Using spatially-exclusive Generalized Additive Models (GAM), dolphin presence was found to be significantly correlated to spring tidal phase, warm water temperature (24–30°C), and salinities ranging from 6–22 PPT. We were also able to use these GAMs to predict dolphin occurrence in the Bay. These predictions were statistically correlated to the actual number of dolphin sighting reported to Chesapeake DolphinWatch during that time. These models for dolphin presence can be implemented as a predictive tool for species occurrence and inform management of this protected species within the Chesapeake Bay.
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Leeney, Ruth H., Simon Berrow, David McGrath, Joanne O'Brien, Ronan Cosgrove, and Brendan J. Godley. "Effects of pingers on the behaviour of bottlenose dolphins." Journal of the Marine Biological Association of the United Kingdom 87, no. 1 (February 2007): 129–33. http://dx.doi.org/10.1017/s0025315407054677.
Full textAbstract:
Trials were carried out in the Shannon estuary, Ireland, to test the effects of continuous (CPs) and responsive pingers (RPs) on bottlenose dolphin behaviour. In controlled trials, active and control pingers were deployed on fixed moorings, with T-PODs—acoustic monitoring devices to detect cetacean activity. In a separate trial, pingers were deployed from a moving boat which actively located dolphin groups in the estuary, and dolphin behaviour was recorded. In the static trials, overall detection rates of dolphin vocalizations on the T-POD were significantly lower in the presence of active CPs, but this was not the case for RPs. Mean inter-click interval values were longer for click trains produced in the presence of inactive RPs than for active RPs, active or inactive CPs. In boat-based trials, both active CPs and RPs appeared to affect bottlenose dolphin behaviour, whereby dolphins immediately left the area at speed and in a highly directional manner, involving frequent leaps.
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Kiszka, Jeremy J. "Atypical associations between dugongs (Dugong dugon) and dolphins in a tropical lagoon." Journal of the Marine Biological Association of the United Kingdom 87, no. 1 (February 2007): 101–4. http://dx.doi.org/10.1017/s0025315407055129.
Full textAbstract:
Several types of relationships link organisms to each other, including competition, predation and various types of associations. This paper presents the first case of association/interaction between dugongs, Dugong dugon, the only strictly marine herbivorous mammal, and three species of tropical dolphins in and around the lagoon of Mayotte (45°10'E 12°50'S), in the western tropical Indian ocean. Data were collected opportunistically from 1999 to 2005 in the surrounding waters of Mayotte from boat (N=2 observations) and ULM (ultra-light motorized vessel, N=2). The dolphin species involved in associations with dugongs were Indo-Pacific bottlenose dolphin, Tursips aduncus, Indo-Pacific humpback dolphin, Sousa chinensis, and spinner dolphin, Stenella longirostris. In one case, dugongs were associated with both bottlenose and humpback dolphins. Associations were observed in the protected waters of the lagoon and outside, along the external slope of the barrier reef. Group size, activity and group structure of each species were recorded. Behavioural observations suggest that dugongs and dolphins were engaged in similar activities, such as travelling, on several occasions and were clearly associated when group formation was tight. If dolphins and dugongs may not associate for feeding purposes, then these interactions may occur: (1) for predation avoidance toward sharks; or (2) without any ecological reasons due to dolphin and dugong habitat overlap around the island.
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Gómez de Segura, A., P. S. Hammond, and J. A. Raga. "Influence of environmental factors on small cetacean distribution in the Spanish Mediterranean." Journal of the Marine Biological Association of the United Kingdom 88, no. 6 (March 17, 2008): 1185–92. http://dx.doi.org/10.1017/s0025315408000386.
Full textAbstract:
Habitat distribution models are one of the most up to date methods to study the habitat usage of wildlife populations. They allow animal distribution to be related to environmental features and also the prediction of the distribution of animals based on this relationship. Seasonal aerial surveys were conducted in central Spanish Mediterranean waters from June 2000 to March 2003 to obtain information on the distribution of cetacean species. Data from the three most common cetacean species (striped dolphin, Stenella coeruleoalba, bottlenose dolphin, Tursiops truncatus, and Risso's dolphin, Grampus griseus) were related, using generalized linear models, to local environmental features: depth, slope, sea surface temperature and chlorophyll concentration. For bottlenose dolphins, no significant relationship was found with any covariate and no dolphins were observed in waters greater than 1000 m. The distribution of both striped and Risso's dolphin was significantly related to depth. The striped dolphin showed a preference for waters between 900 and 1500 m deep and Risso's dolphin for waters more than 1500 m deep. In addition, for the latest two species, maps of distribution were predicted by means of the spatial models. The areas of higher probabilities of occurrence coincide to a large extent with the marine protected areas previously proposed for the conservation of oceanic cetacean species.
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Tomo, Ikuko, and Catherine M. Kemper. "Strandings in St Vincent Gulf Bioregion, South Australia: 12-Year Study Monitors Biology and Pathology of Cetaceans." Oceans 3, no. 4 (September 26, 2022): 439–63. http://dx.doi.org/10.3390/oceans3040030.
Full textAbstract:
The semi-enclosed environment of the St Vincent Gulf Bioregion and its fauna are impacted by many human activities. Long-term monitoring of cetaceans is vital. Records of collected specimens (173) and those not examined by the South Australian Museum (98 non-specimens) from 2009–2020 were analyzed. Necropsies were carried out on most carcasses using gross, histopathological, and diagnostic assessment of pathogens, organs, and skin lesions. The relative age and circumstance of death were assigned. Baleen whales (five species) and odontocetes (eight species) were studied. Indo-Pacific bottlenose dolphins (Tursiops aduncus) and common dolphins (Delphinus delphis) were frequently recorded and analyzed in detail. Anthropogenic cases were prevalent (21%). Many dolphins (62%) were immature males. Disease (73%) was the most frequently recorded circumstance of death. The most common pathological change was inflammatory disease, including infectious pneumonia. In Indo-Pacific bottlenose dolphins, infectious disease was more prevalent in the greater St Vincent Gulf Bioregion than in the Adelaide Dolphin Sanctuary. Microbe testing confirmed 32 species of bacteria, 2 fungi, and 1 virus. Nematodes and trematodes were recorded throughout the study, sometimes in association with microbes. Toxoplasma gondii was observed in an Indo-Pacific bottlenose dolphin. Severe traumatic injury was recorded in many dolphins, including anthropogenic cases. A tumor (leiomyoma) was described from a single common dolphin. This study provides an important baseline for the future monitoring of emerging infectious and chronic diseases, and anthropogenic threats in the region.
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Avila, Isabel Cristina, Carolina Garcia, and Juan Carlos Bastidas. "A note on the use of dolphins as bait in the artisanal fisheries off Bahía Solano, Chocó, Colombia." J. Cetacean Res. Manage. 10, no. 2 (February 15, 2023): 179–82. http://dx.doi.org/10.47536/jcrm.v10i2.652.
Full textAbstract:
Dolphin hunting for fishing bait in Bahía Solano, Chocó, Colombia, was evaluated during eight months, between July 2005 and April 2006. Interviews were conducted with 122 fishermen (18.2% of the registered fishermen in the zone), who cover at most 890km2 when fishing (approximately 2.3% of the Pacific Territorial Sea of Colombia), and data obtained from landings at a fishing company. Only fishermen using longlines (37.3%) confirmed using dolphins as bait. It was not possible to obtain additional information about date, specific location or dolphin species, but the most probable captured species were common bottlenose dolphin and pantropical spotted dolphin. Nine dolphins were killed during the study period (1.1 dolphins/month) and extrapolating these numbers to all fishermen using longlines in the region (250), 24 dolphins might have been taken during the study period (3 dolphins/month). Fish species caught using dolphin bait include Pacific bearded brotula, groupers and smooth-hound.
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Borges Costa, Ana Paula, Pedro Fruet, Fábio Gonçalves Daura-Jorge, Paulo César Simões-Lopes, Paulo Henrique Ott, Victor Hugo Valiati, and Larissa Rosa de Oliveira. "Bottlenose dolphin communities from the southern Brazilian coast: do they exchange genes or are they just neighbours?" Marine and Freshwater Research 66, no. 12 (2015): 1201. http://dx.doi.org/10.1071/mf14007.
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The genetic structure of bottlenose dolphin communities found along the southern Brazilian coast is reported in this study. Genetic structure analysis using biopsy samples from free ranging dolphins and tissue samples from stranded dolphins revealed a fine-scale population structure among three distinct groups. The first genetically distinct group was composed of resident dolphins of Laguna with a high degree of site fidelity. The second group was composed of one photo-identified dolphin, previously recognised by its interaction with fishermen, and dolphins that stranded near the mouth of Tramandaí Lagoon. Moderate nuclear and low mitochondrial gene diversity was found in dolphins of those coastal communities, whereas most of the dolphins stranded along the coast showed markedly higher levels of gene diversity at both markers. These stranded dolphins of unknown origin formed the third distinct group, which may be part of a larger offshore community. These results demonstrate the presence of at least three bottlenose dolphin clusters along this portion of the Brazilian coast, with the coastal specimens appearing to be only neighbours of a larger offshore community that eventually strands along the coast, highlighting the importance of the establishment of management and conservation measures for the species at a local scale.
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Sánchez-Cabanes, Alicia, Maja Nimak-Wood, Nicola Harris, and Renaud De Stephanis. "Habitat preferences among three top predators inhabiting a degraded ecosystem, the Black Sea." Scientia Marina 81, no. 2 (June 14, 2017): 217. http://dx.doi.org/10.3989/scimar.04493.07a.
Full textAbstract:
This study investigated whether there is evidence of widespread niche partitioning based on environmental factors in the Black Sea and tested the hypothesis that physiographic factors may be employed as predictors. It addresses poorly researched areas with good habitat potential for the only three cetacean subspecies living in this area: the Black Sea short-beaked common dolphin (Delphinus delphis spp. ponticus), the Black Sea bottlenose dolphin (Tursiops truncatus spp. ponticus) and the Black Sea harbour porpoise (Phocoena phocoena spp. relicta). Generalized additive models (GAMs) were used to analyse data collected from multiple sources. In total, 745 sightings of the three species between 1998 and 2010 throughout the Black Sea were included. The analysis found depth and sea surface temperature to be the most important variables for separating the occurrence of the three species. Common dolphins occurred mainly in deep waters and in areas where the sea surface temperature was low, bottlenose dolphins were distributed primarily in shallower and warmer waters than common dolphins, and harbour porpoises were distributed in shallower waters with lower sea surface temperature than bottlenose dolphins. This study suggests strong niche segregation among the three cetacean species. The study is also the first contribution to the basic information of cetacean species distribution and habitat preferences in the Black Sea as a whole. Knowledge of the distribution of the three dolphin species in the study area is essential to establish conservation measures for these populations.
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Pierce, Graham J., Mara Caldas, Jose Cedeira, M. Begoña Santos, Ángela Llavona, Pablo Covelo, Gema Martinez, Jesus Torres, Mar Sacau, and Alfredo López. "Trends in cetacean sightings along the Galician coast, north-west Spain, 2003–2007, and inferences about cetacean habitat preferences." Journal of the Marine Biological Association of the United Kingdom 90, no. 8 (July 6, 2010): 1547–60. http://dx.doi.org/10.1017/s0025315410000664.
Full textAbstract:
Since mid-2003, systematic monthly sightings surveys for cetaceans have been carried out in Galicia (north-west Spain) from observation points around the coastline, with the aim of providing baseline data on cetacean distribution and habitat use to underpin future conservation measures. Here we summarize results for September 2003 to October 2007. The most frequently recorded species were the bottlenose dolphin (Tursiops truncatus, seen during 10.7% of observation periods), common dolphin (Delphinus delphis, 3.7%), harbour porpoise (Phocoena phocoena, 1.6%), Risso's dolphin (Grampus griseus, 0.4%) and short-finned pilot whale (Globicephala melas, 0.2%). The three most common species showed different distribution patterns along the coast. In terms of habitat preferences, bottlenose dolphins were seen to be associated with more productive areas (areas with higher chlorophyll-a concentrations) where the continental shelf was wider while both common dolphins and harbour porpoises were seen most frequently in less productive areas where the continental shelf is narrowest. Possible reasons for differences in habitat use include differing diets. In Galician waters, all three main cetacean species feed primarily on fish that are common in shelf waters, and in the case of blue whiting (the most important species in the stomach contents of common and bottlenose dolphins) abundant also on the slope. All three cetaceans feed on blue whiting while scad is important in diets of common dolphin and porpoise. It is also possible that porpoises do not use areas frequented by bottlenose dolphins in order to avoid aggressive interactions. Retrospective evaluation of the sampling regime, using data from the 2500 observation periods during 2003–2007 suggests that the overall sightings rates for all species (taking into account observation time and between-site travel time) would be higher if average observation duration was increased to at least 40 minutes. On the other hand, confidence limits on sightings rates stabilized after around 1000 observation periods, suggesting that the number of sites visited or the frequency of visits could be substantially reduced.
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Thompson, Paul. "The bottlenose dolphin." Trends in Ecology & Evolution 5, no. 11 (November 1990): 390. http://dx.doi.org/10.1016/0169-5347(90)90126-x.
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Walton, M. J., M. A. Silva, S. M. Magalhães, R. Prieto, and R. S. Santos. "Using blubber biopsies to provide ecological information about bottlenose dolphins (Tursiops truncatus) around the Azores." Journal of the Marine Biological Association of the United Kingdom 87, no. 1 (February 2007): 223–30. http://dx.doi.org/10.1017/s0025315407054537.
Full textAbstract:
Fatty acid profiles were used to investigate aspects of bottlenose dolphin populations around the Azores archipelago. Biopsy samples were obtained from 70 dolphins during the period 2002–2004. No statistically significant differences in profiles were found between different island groups, between sexes or between year of sampling. Thus no evidence was seen for island group fidelity, in contrast to bottlenose dolphins found around similar island groups such as the Hawaiian archipelago or the Bahamas. The findings are consistent with concurrent genetic and photo-identification studies on dolphins in the Azores.
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Adamczak, S. K., C. Kemper, and I. Tomo. "Strandings of dolphins in the Adelaide Dolphin Sanctuary, South Australia." J. Cetacean Res. Manage. 19, no. 1 (January 24, 2023): 105–11. http://dx.doi.org/10.47536/jcrm.v19i1.418.
Full textAbstract:
The Adelaide Dolphin Sanctuary was gazetted in 2005 to protect a resident population of Indo-Pacific bottlenose dolphins (Tursiops aduncus) thatlives in a heavily impacted urban environment. This study assesses the numbers and types of strandings before and after the creation of the sanctuary.Monitoring took place during 1987–2013, when 57 events were reported and 53 carcasses were examined by post-mortem. Events were assignedto a circumstance of death that combined post-mortem results and/or anecdotal information. The majority of records were Indo-Pacific bottlenosedolphins (n = 47, 82%) but a few common dolphins (Delphinus delphis, n = 7, 12%) were also documented. Many (n = 19/46, 41%) of the Indo-Pacific bottlenose dolphins were 1 year old or less. Strandings averaged 2.19 per annum for all dolphin species and 1.80 for Indo-Pacific bottlenosedolphins. When pre- (n = 20) and post-sanctuary (n = 27) data were compared for Indo-Pacific bottlenose dolphins, anthropogenic events decreasedfrom 30% (n = 6/20) to 7% (n = 2/27) and no intentional (illegal) killings or entanglements were recorded after 2004. Unintentional anthropogenicmortalities were primarily boat collisions (n = 4 out of 5 cases). Disease was the most frequently recorded circumstance of death (n = 21) andalthough the number of cases increased after 2004, this may have been due to improved pathology investigations. Live strandings were rare duringthe study (n = 2). Despite a significant increase in overall dolphin mortalities pre- and post-sanctuary, the number of human-induced mortalityevents decreased significantly. Continued monitoring and post-mortems of carcasses is recommended for managing dolphins in the sanctuary.
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Anderwald, Pia, Michael Damien Haberlin, Mary Coleman, Oliver Ó Cadhla, Anneli Englund, Fleur Visser, and Michelle Cronin. "Seasonal trends and spatial differences in marine mammal occurrence in Broadhaven Bay, north-west Ireland." Journal of the Marine Biological Association of the United Kingdom 92, no. 8 (September 25, 2012): 1757–66. http://dx.doi.org/10.1017/s0025315412001397.
Full textAbstract:
Long-term monitoring programmes of a comparatively small area complement larger scale, but temporally limited surveys and can provide extensive datasets on seasonal occurrence and fine-scale habitat use of multiple species. A marine mammal monitoring programme, involving year-round, land-based observations, has been conducted in Broadhaven Bay candidate Special Area of Conservation, north-west Ireland, during 2002, 2005 and 2008–2011. Nine cetacean and two seal species have been recorded, with grey seal, harbour porpoise, common and bottlenose dolphins, and minke whale present throughout the year. Generalized additive models, taking into account observer effort, sighting conditions (sea state) and interannual variation, did not reveal any significant seasonal patterns in the occurrence of grey seals, bottlenose dolphins and minke whales. On the other hand, common dolphin presence in Broadhaven Bay was highest during autumn and winter. Bottlenose dolphins could be separated spatially from both common dolphins and minke whales in a classification tree by their preferential use of the shallower inshore areas of the bay (<30 m depth). However, common dolphins and minke whales, which occurred mainly in the deeper outer section of Broadhaven Bay, could not be spatially distinguished from each other, and grey seals were distributed over the entire bay. Broadhaven Bay represents an important marine mammal habitat with respect to overall species diversity and the regular occurrence of bottlenose dolphin, harbour porpoise, grey and harbour seals (all listed under Annex II of the EU Habitats Directive).
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Coscarella, Mariano A., Silvana L. Dans, Mariana Degrati, Griselda V. Garaffo, and Enrique A. Crespo. "Bottlenose dolphins at the southern extreme of the south-western Atlantic: local population decline?" Journal of the Marine Biological Association of the United Kingdom 92, no. 8 (December 6, 2011): 1843–49. http://dx.doi.org/10.1017/s0025315411001901.
Full textAbstract:
The management scheme of Marine Protected Areas (MPAs) includes monitoring protocols but such activities are not always carried out. This is the case for Golfo San José, a MPA in northern Patagonia, Argentina. It was created in 1975 for the protection of the southern right whale (Eubalaena australis) breeding grounds. Other components of the system, such as dolphin populations have received little attention. This study is the first attempt to estimate sighting rates, group size and overall abundance of a bottlenose dolphin (Tursiops truncatus) population in Golfo San José and adjacent areas after 30 years. An analysis of the seasonal sighting rates indicates that bottlenose dolphins were present in the study area throughout the year but a decline in group size and abundance and major shift in distribution was detected when compared with previous published reports. The settlement of the MPA failed to secure the persistence of the bottlenose dolphin population within its boundaries. Possible explanations for the detected decline are addressed including increased natural mortality, human induced mortality and disturbance, resources depletion and environmental shift.
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Moreno Escobar, Jesús Jaime, Oswaldo Morales Matamoros, Erika Yolanda Aguilar del Villar, Ricardo Tejeida Padilla, Ixchel Lina Reyes, Brenda Espinoza Zambrano, Brandon David Luna Gómez, and Víctor Hugo Calderón Morfín. "Non-Parametric Evaluation Methods of the Brain Activity of a Bottlenose Dolphin during an Assisted Therapy." Animals 11, no. 2 (February 6, 2021): 417. http://dx.doi.org/10.3390/ani11020417.
Full textAbstract:
Dolphin-Assisted Therapies (DAT) are alternative therapies aimed to reduce anxiety levels, stress relief and physical benefits. This paper is focused on measuring and analyzing dolphins brain activity when DAT is taking place in order to identify if there is any differences in female dolphin’s neuronal signal when it is interacting with control or intervention subjects, performing our research in Delfiniti, Ixtapa, Mexico facilities. We designed a wireless and portable electroencephalographic single-channel signal capture sensor to acquire and monitor the brain activity of a female bottle-nose dolphin. This EEG sensor was able to show that dolphin activity at rest is characterized by high spectral power at slow-frequencies bands. When the dolphin participated in DAT, a 23.53% increment in the 12–30 Hz frequency band was observed, but this only occurred for patients with some disease or disorder, given that 0.5–4 Hz band keeps it at 17.91% when there is a control patient. Regarding the fractal or Self-Affine Analysis, we found for all samples studied that at the beginning the dolphin’s brain activity behaved as a self-affine fractal described by a power-law until the fluctuations of voltage reached the crossovers, and after the crossovers these fluctuations left this scaling behavior. Hence, our findings validate the hypothesis that the participation in a DAT of a Patient with a certain disease or disorder modifies the usual behavior of a female bottle-nose dolphin.
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FASICK, JEFFRY I., THOMAS W. CRONIN, DAVID M. HUNT, and PHYLLIS R. ROBINSON. "The visual pigments of the bottlenose dolphin (Tursiops truncatus)." Visual Neuroscience 15, no. 4 (April 1998): 643–51. http://dx.doi.org/10.1017/s0952523898154056.
Full textAbstract:
To assess the dolphin's capacity for color vision and determine the absorption maxima of the dolphin visual pigments, we have cloned and expressed the dolphin opsin genes. On the basis of sequence homology with other mammalian opsins, a dolphin rod and long-wavelength sensitive (LWS) cone opsin cDNAs were identified. Both dolphin opsin cDNAs were expressed in mammalian COS-7 cells. The resulting proteins were reconstituted with the chromophore 11-cis-retinal resulting in functional pigments with absorption maxima (λmax) of 488 and 524 nm for the rod and cone pigments respectively. These λmax values are considerably blue shifted compared to those of many terrestrial mammals. Although the dolphin possesses a gene homologous to other mammalian short-wavelength sensitive (SWS) opsins, it is not expressed in vivo and has accumulated a number of deletions, including a frame-shift mutation at nucleotide position 31. The dolphin therefore lacks the common dichromatic form of color vision typical of most terrestrial mammals.
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Laporta, Paula, Pedro Fruet, and Eduardo Secchi. "First estimate of common bottlenose dolphin (Tursiops truncatus) (Cetacea, Delphinidae) abundance off Uruguayan Atlantic coast." Latin American Journal of Aquatic Mammals 11, no. 1-2 (January 8, 2017): 144–54. http://dx.doi.org/10.5597/00223.
Full textAbstract:
The common bottlenose dolphin Tursiops truncatus is often observed throughout the oceanic coast of Uruguay. Historically, its distribution was wider, including the estuary of the Río de la Plata, but currently its occurrence seems to be restricted mainly to the Uruguayan Atlantic coast (Rocha Department). Conflicting interests and tradeoffs between conservation and development are being generated in Uruguay. On one hand, the establishment of protected areas, responsible tourism and sustainable fisheries are promoted, while on the other hand, foreign exploitation of natural resources and development of mega-infrastructure in coastal zone are facilitated. In this work, we provide the first estimate of bottlenose dolphin’s abundance along the Uruguayan Atlantic coast. These results can be used as baseline information for monitoring population trends and guiding conservation actions for bottlenose dolphins in Uruguay. Mark-recapture models were applied to data of photoidentified animals with long-lasting natural marks. Total population size estimates of 63 individuals (95% CI = 54–74) and 61 (95% CI = 53–73) were obtained from closed and open population models, respectively. Although the estimates are within the range of values obtained for other coastal bottlenose dolphin populations in the Southwest Atlantic Ocean, as well as other regions of the world, it is lower than the values reported for populations inhabiting open habitats. This small population is probably vulnerable to non-natural removals, environmental and demographic stochasticity. Therefore, precautionary actions are recommended given the planned development for this coastal region.
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Mujiyanto, Mujiyanto, Riswanto Riswanto, Dharmadi Dharmadi, and Wildan Ghiffary. "COMPOSITION AND DISTRIBUTION OF DOLPHIN IN SAVU SEA NATIONAL MARINE PARK, EAST NUSA TENGGARA." Indonesian Fisheries Research Journal 23, no. 2 (February 12, 2018): 55. http://dx.doi.org/10.15578/ifrj.23.2.2017.55-67.
Full textAbstract:
Dolphins are one of the most interesting cetacean types included in family Delphinidae or known as the oceanic dolphins from genus Stenella sp. and Tursiops sp. Migration and abundance of dolphins are affected by the presence of food and oceanographic conditions. The purpose of this research is to determine the composition and distribution of dolphins in relation to the water quality parameters. Benefits of this research are expected to provide information on the relationship between distributions of the family Delphinidae cetacean (oceanic dolphins) and oceanographic conditions. The method for this research is descriptive exploratory, with models onboard tracking survey. Field observations were done in November 2015 and period of March-April 2016 outside and inside Savu Sea National Marine Park waters. The sighting of dolphin in November and March-April found as much seven species: bottlenose dolphin, fraser’s dolphin, pantropical spotted dolphin, risso’s dolphin, rough-toothed dolphin, spinner dolphin and stripped dolphin. The highest species distribution noted in the Savu Sea is spinner dolphin, pantropical spotted dolphin, rough-toothed dolphin and frazer’s dolphin. The existence of dolphins in Savu Sea is more related with sea surface temperature than others oceanographic parameters. This condition is suspected due to the influence of sea surface temperature to body temperature of dolphin especially for foraging activities. The habit of dolphin is more active around Sumba Island and Daratan Timor waters while in the evening the animal is usually going to Manggarai and Rote Ndao Islands waters to rest.
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Kassamali-Fox, Ayshah, Fredrik Christiansen, Laura J. May-Collado, Eric A. Ramos, and Beth A. Kaplin. "Tour boats affect the activity patterns of bottlenose dolphins (Tursiops truncatus) in Bocas del Toro, Panama." PeerJ 8 (March 30, 2020): e8804. http://dx.doi.org/10.7717/peerj.8804.
Full textAbstract:
Bottlenose dolphins (Tursiops truncatus) of the Bocas del Toro archipelago are targeted by the largest boat-based cetacean watching operation in Panama. Tourism is concentrated in Dolphin Bay, home to a population of resident dolphins. Previous studies have shown that tour boats elicit short-term changes in dolphin behavior and communication; however, the relationship of these responses to the local population’s biology and ecology is unclear. Studying the effects of tour boats on dolphin activity patterns and behavior can provide information about the biological significance of these responses. Here, we investigated the effects of tour boat activity on bottlenose dolphin activity patterns in Bocas del Toro, Panama over 10 weeks in 2014. Markov chain models were used to assess the effect of tour boats on dolphin behavioral transition probabilities in both control and impact scenarios. Effect of tour boat interactions was quantified by comparing transition probabilities of control and impact chains. Data were also used to construct dolphin activity budgets. Markov chain analysis revealed that in the presence of tour boats, dolphins were less likely to stay socializing and were more likely to begin traveling, and less likely to begin foraging while traveling. Additionally, activity budgets for foraging decreased and traveling increased as an effect of tour boat presence. These behavioral responses are likely to have energetic costs for individuals which may ultimately result in population-level impacts. Boat operator compliance with Panamanian whale watching regulations is urgently needed to minimize potential long-term impacts on this small, genetically distinct population and to ensure the future viability of the local tourism industry.
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TORREBLANCA, ESTEFANÍA, RAIMUNDO REAL, JUAN ANTONIO CAMIÑAS, DAVID MACÍAS, SALVADOR GARCÍA-BARCELONA, and JOSÉ CARLOS BÁEZ. "Spatial and temporal partitioning of the Western Mediterranean Sea by resident dolphin species." Mediterranean Marine Science 24, no. 1 (January 17, 2023): 34–49. http://dx.doi.org/10.12681/mms.25543.
Full textAbstract:
A classic issue in ecology is to understand how similar species coexist in a given area (i.e., sympatry). The situation of dolphins in the Western Mediterranean Sea may represent a special case of sympatry in that three similar species (the short-beaked common dolphin [Delphinus delphis], the striped dolphin [Stenella coeruleoalba], and the bottlenose dolphin [Tursiops truncatus) are under strong human impacts in the same area. From the viewpoint of ecology and conservation biology, it is challenging to determine how these three dolphin species live together and avoid competitive exclusion in the setting of such impacts. The Spanish Institute of Oceanography has a dataset of dolphin species opportunistic sightings. Using these data, we constructed three binary variables, comprising the sighting of one species versus the sighting of either of the other two species. We obtained three significant probability models after performing logistic regression of these binary variables on a set of spatio-temporal explanatory variables. We analysed these models from the perspective of fuzzy set theory by applying the favourability function to the probability models, fuzzy operations overlap, and entropy. The results show that common dolphins are differentially favoured in the eastern part of the study area and far away from main shipping routes. The striped dolphin was differentially favoured in the western part of the study area, above deep waters, near main shipping routes, and in summer and spring. Finally, bottlenose dolphins were differentially favoured in the mid-western part of the study area, in winter, and over shallow waters.
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Houser, Dorian S., Cory Champagne, and Daniel E. Crocker. "Thyroid-Stimulating Hormone Stimulation Tests in the Bottlenose Dolphin (Tursiops truncatus)." Journal of Zoological and Botanical Gardens 2, no. 2 (May 26, 2021): 265–72. http://dx.doi.org/10.3390/jzbg2020018.
Full textAbstract:
Stimulation of the thyroid with thyroid-stimulating hormone (TSH) is a potentially useful diagnostic of thyroid dysfunction, but little is known about the response of the thyroid to TSH stimulation in bottlenose dolphins (Tursiops truncatus). To better characterize the response of the dolphin thyroid to TSH stimulation, five adult dolphins participated in a TSH stimulation study. Dolphins voluntarily beached onto a padded mat and were given a 1.5 mg intramuscular injection of human recombinant TSH. Blood samples collected the day prior, at multiple intervals the day of, and daily for three days after the injection were analyzed via radioimmunoassay for free and total triiodothyronine (fT3 and tT3), and free and total thyroxine (fT4 and tT4). Significant increases in circulating fT3, fT4, and tT4 were observed with peaks occurring for all hormones the day after the TSH injection; maximal increases were 44%, 47%, and 23% for each hormone, respectively. Temporal patterns in the hormones potentially reflected feedback mechanisms countering the surge in fT3 following stimulation. Though recombinant human TSH was effective at stimulating hormone release, it is likely that use of dolphin or dolphin-derived TSH would enhance the clinical utility of the stimulation test, as would the development of antibodies specific to dolphin TSH.