Tursiops Aduncus Research Articles

Dredging activity in a highly urbanised estuary did not affect the long-term occurrence of Indo-Pacific bottlenose dolphins and long-nosed fur seals.

Dredging is an excavation activity used worldwide in marine and freshwater environments to create, deepen, and maintain waterways, harbours, channels, locks, docks, berths, river entrances, and approaches to ports and boat ramps. However, dredging impacts on marine life, including marine mammals (cetaceans, pinnipeds, and sirenians), remain largely unknown. Here we quantified the effect of dredging operations in 2005 and 2019 on the occurrence of Indo-Pacific bottlenose dolphins (Tursiops aduncus) and long-nosed fur seals (Arctocephalus forsteri) in the Port River estuary, a highly urbanized estuary in Adelaide, South Australia. We applied generalised linear models to two long-term sighting datasets (dolphins: 1992-2020, fur seals: 2010-2020), to analyse changes in sighting rates as a function of dredging operations, season, rainfall, and sea surface temperature. We showed that the fluctuations in both dolphin and fur seal occurrences were not correlated with dredging operations, whereas sea surface temperature and season were stronger predictors of both species sighting rates (with seals more prevalent during the colder months, and dolphins in summer). Given the highly industrial environment of the Port River estuary, it is possible that animals in this area are habituated to high noise levels and therefore were not disturbed by dredging operations. Future research would benefit from analysing short-term effects of dredging operations on behaviour, movement patterns and habitat use to determine effects of possible habitat alteration caused by dredging.

Inter- and intra-specific trophic interactions of coastal delphinids off the eastern coast of South Africa inferred from stable isotope analysis

Dietary tracers, such as bulk stable carbon (δ13C) and nitrogen (δ15N) isotopes, can be used to investigate the trophic interactions of marine predators, which is useful to assess their ecological roles within communities. These tracers have also been used to elucidate population structure and substructure, which is critical for the better identification of management units for these species affected by a range of threats, particularly bycatch in fishing gears. Off eastern South Africa, large populations of Indo-Pacific bottlenose (Tursiops aduncus) and common dolphins (Delphinus delphis) co-occur and are thought to follow the pulses of shoaling sardines (Sardinops sagax) heading north-east in the austral winter. Here we used δ13C and δ15N to investigate the trophic interactions and define ecological units of these two species along a ≈800 km stretch of the east coast of South Africa, from Algoa Bay to the coast of KwaZulu-Natal. Common and bottlenose dolphin dietary niche overlapped by 39.7% overall in our study area, with the highest overlap occurring off the Wild Coast (40.7% at Hluleka). Both stable isotopes were significantly enriched in bottlenose dolphins sampled in the western part of our study area (i.e., Algoa Bay and Amathole) compared to eastern animals (i.e., from Hluleka, Pondoland, and KZN). In areas where genetic information is not available or is insufficient, food web tracers (such as stable isotopes) can be used to group individuals based on trophic ecology, which can provide ecological units for management of populations. The distinct isotope signatures found here for bottlenose dolphins can, therefore, be used as management units for conservation efforts in the future.

External indicators of fisheries interactions in known bycaught dolphins from bather protection nets along the KwaZuluNatal coastline, South Africa

Detailed examinations of dolphins incidentally caught in bather protection nets along the KwaZulu‐Natal coastline, South Africa, over the past 10 years have yielded a dataset that can assist in the examination of external signs of bycatch. Investigating these external signs of fisheries interactions could aid in determining whether they could be used as unequivocal indicators of entanglement in stranded dolphins for which cause of death is unknown. The aim of this study was to investigate the occurrence of netmarks and other external injuries on individuals of two dolphin species (Tursiops aduncus and Sousa plumbea), both bycaught and stranded, along the south‐east coast of South Africa. Necropsy reports and photographs of 107 bycaught and 15 stranded dolphins between 2010 and 2017 were investigated to determine prevalence of netmarks and other external injuries in relation to species, sex, age class, and water temperature. Our results indicated that 36% of the bycaught dolphins and 13% of stranded dolphins showed netmarks on the skin. In bycaught animals, females were more likely to show netmarks (58%) and the majority of dolphins with netmarks were immatures (66%; immatures included calves, neonates and subadults). There was little evidence for water temperature affecting the appearance of netmarks. Furthermore, species, sex or age class did not play a significant role in the probability of netmark occurrence. Other external injuries were also observed in the bycaught (3–50%) and stranded animals (7–100%), with subcutaneous bruising being the most prominent sign in bycaught animals. Our study showed that only a small percentage of known bycaught animals actually present external signs of entanglement. Thus, additional evidence, such as histopathological examinations, is required to reliably identify entanglement cases in stranded animals.

Strandings in St Vincent Gulf Bioregion, South Australia: 12-Year Study Monitors Biology and Pathology of Cetaceans

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.

Probable signature whistle production in Atlantic white‐sided (Lagenorhynchus acutus) and short‐beaked common (Delphinus delphis) dolphins near Cape Cod, Massachusetts

Probable signature whistle production in Atlantic white‐sided (<i>Lagenorhynchus acutus</i>) and short‐beaked common (<i>Delphinus delphis</i>) dolphins near Cape Cod, Massachusetts

Exploring lipid affinities of persistent organic pollutants and MeO-PBDEs in blubber of marine mammals

Although lipophilic compounds have been the focus of numerous studies in marine mammals, their association with lipids is widely accepted, but rarely scrutinized. This pilot study aimed to investigate potential relationships between individual lipids from different lipid classes identified through a non-targeted Nuclear Magnetic Resonance (NMR) based lipidomics approach and legacy POPs in the blubber of long-finned pilot whales, sperm whales, common bottlenose dolphins, and Indo-Pacific bottlenose dolphins. Concentrations of selected POPs such as HCB and HCHs in sperm whales from Tasmania were found to differ from those in long-finned pilot whales and common bottlenose dolphins from the same location. Profiles of NMR spectra measured in blubber of sperm whales were also distinctly different compared to the pilot whales and common bottlenose dolphins. Two groups of Indo-Pacific bottlenose dolphins from South Australia that were 20 years apart showed highly comparable profiles of NMR signals despite having higher concentrations of several POP classes in the more recent group. More specific correlations were investigated between selected POPs (n = 12) and all detected NMR signals (n = 63) in all species. Outcomes were species-specific, but difficult to interpret due to the lack of available literature for marine mammals and the small sample sizes per species. Because of the key role of lipids in the bioaccumulation of POPs and in the incidence of diseases, more attention should be given to the identification and characterization of lipid species in future toxicological studies. However, future studies should focus on one marine mammal species to increase sample sizes and limit the number of confounding factors, such as diet, that can influence POP and lipid levels and profiles.

Histomorphological stratification of blubber of three dolphin species from subtropical waters.

Blubber is a highly specialized and dynamic tissue unique to marine mammals and presents a reflection of the individuals' nutrition, environment, and life history traits. Few studies have investigated the histomorphology of cetacean blubber in subtropical environments. The aim of this study was to investigate the blubber histomorphology of three different dolphin species off the subtropical KwaZulu-Natal coast, South Africa, using adipocyte cell size, number, and density. Blubber tissue samples from the saddle area of 43 incidentally bycaught animals (fourSousa plumbea, 36 Tursiops aduncus, and threeDelphinus delphis) were used to compare cell parameters between blubber layers. Samples were divided into the upper third (corresponding to the superficial layer closest to the epidermis), middle third, and lower third (corresponding to the deep layer). For T. aduncus, factors potentially affecting blubber histomorphology, such as sex, age class, and season, were also assessed. Our results showed that no stratification was present in S. plumbea, which could be ascribed to the species' warmer inshore habitat, large body size, and apparent lower mobility. For T. aduncus and D. capensis, however, blubber stratification was determined, characterized by a gradual transition of cell size, number, and density between layers rather than clearly defined layers. Significant differences in adipocyte cell number and density were found for different sexes and age classes of T. aduncus. However, there were no significant differences between seasons, which was attributed to the small temperature differences between seasons. This study represents the first investigation of odontocete blubber histomorphology in subtropical waters. It is recommended that future studies investigate blubber lipid content, while also taking into consideration the reproductive status of the females and the temperature range of their study area. It is hoped that our results, in conjunction with histopathology and other health indicators, could assist in assessing health and body condition.

Abundance, spatial distribution and threats to Indo-Pacific bottlenose dolphins (Tursiops aduncus) in an Important Marine Mammal Area in Tanzania

Abundance estimates of cetaceans in the western Indian Ocean are rare, but important, as many cetacean populations are under threat, especially those in coastal habitats. This study aimed to generate first estimates of abundance for Indo-Pacific bottlenose dolphins (Tursiops aduncus), assessed as Near Threatened on the IUCN Red List, in an area identified by the Marine Mammal Protected Area Task Force as an ‘Important Marine Mammal Area’. Two study sites were surveyed along the east and west coastlines of the Pemba Channel, Tanzania. In west Pemba, between 2014 and 2016 four boat-based visual surveys conducted a total of 2467 km of survey effort sighting a total of 16 groups of T. aduncus. Abundance was estimated using mark-recapture models of photo-identified individuals as 83 animals (CV 7.8%, 95% CI 72-97) in the 1084km2 study area. In the Tanga study area in 2016 two boat-based visual surveys covered 1254 km of effort during which 15 groups of T. aduncus were sighted, resulting in a photo-ID based mark-recapture abundance estimate of 196 (CV 8.9%, 95% CI 165-233) individuals in the 1562 km2 study site. Group encounter rate for this species in Tanga was double that recorded in the Pemba study site. A total of 23% of identified dolphins bore the scars of interactions with fishing gear.

Demographics and viability of an estuarine community of Indo‐Pacific bottlenose dolphins

AbstractWildlife management requires reliable demographic information to assess the status of a population and its vulnerability to threats. This study calculated age class‐ and sex‐specific demographic parameters and assessed the viability of a community of Indo‐Pacific bottlenose dolphins (Tursiops aduncus) resident to the Peel‐Harvey Estuary in Western Australia. Boat‐based photo‐identification surveys (n = 483) were conducted between 2016 and 2019. A population viability analysis (PVA) was used to assess the community status and evaluate the effects of adult female and calf mortality, and reproduction on population growth rate. The community comprised 88 (SD = 4.43) individuals with a sex ratio close to parity in all but the adult age class where it was skewed towards females. Demographic changes in this community are driven by births, deaths, and the likely permanent emigration of juvenile males. No immigration was observed. The population is stable (r = −0.004, SD = 0.062) given the current demographic rates. To maintain a community of ~90 individuals, management should consider action to lower adult female and calf mortality. This should involve aiming for zero human caused mortality and ensuring adverse impacts to the population are considered in future development planning.

Human-bottlenose dolphin interactions within wildlife tourism, ocean recreation and fisheries

Bottlenose dolphins ( Tursiops truncatus and Tursiops aduncus; BND) live in coastal waters, prompting frequent contact with humans. Interaction with BND can be either planned (e.g. swim-with-dolphin experiences) or chance (e.g. BND surfing on boat wakes). These charismatic cetaceans are common in many forms of wildlife tourism, including marine wildlife tours, swim-with-dolphin experiences and hand feeding. BND also interact with humans by chance during ocean recreation activities, such as surfing, swimming and boating. Within fisheries, there is both cooperation and conflict between humans and BND. Through a literature review, this paper highlights the effects such interactions cause to both BND and humans with a focus on wildlife tourism, ocean recreation and fisheries.

The first study of genetic diversity and population structure of Indo-Pacific bottlenose dolphin (Tursiops aduncus) and pantropical spotted dolphin (Stenella attenuata) in the Thai Andaman Sea based on ISSR.

Background and Aim:The Indo-Pacific bottlenose dolphin, Tursiops aduncus, and the pantropical spotted dolphin, Stenella attenuata, are protected marine mammals in Thailand; however, knowledge regarding the populations of both species in Thai seas is minimal. We aimed to reveal the genetic diversity and population structure of two species, T. aduncus, and S. attenuata, based on inter-simple sequence repeats (ISSRs).Materials and Methods:Samples of stranded T. aduncus (n = 30) and S. attenuata (n = 23) found along Thai Andaman Sea coasts from 1998 to 2018 were used in this study. A total of 17 and 16 ISSR primers that produced clear and polymorphic bands were selected for T. aduncus and S. attenuata, respectively.Results:The highest percentages of polymorphic bands for T. aduncus and S. attenuata were 93.750% and 92.857%, respectively. Phylogenetic dendrograms indicated that the population of each species was clustered into three groups. This outcome was consistent with the genetic population structure, as both suggested three genetic clusters (DK = 3). Genetic diversity analysis revealed that the average Shannon’s information index (I) was 1.926 ± 0.066 for T. aduncus and 1.714 ± 0.090 for S. attenuata, which indicate a high level of genetic variation. Further, low fixation index (F) values were observed for T. aduncus and S. attenuata at −0.231 ± 0.024 and −0.312 ± 0.042, respectively, suggesting that inbreeding is unlikely to have occurred for both species over the past decades.Conclusion:At least three genetic clusters of both species were found in the Thai Andaman Sea, and the diversity indices of each species indicated that these species are not at a critical level for extinction. However, monitoring their population status should be prioritized to observe any future changes in the level of diversity.

Association patterns and community structure among female bottlenose dolphins: environmental, genetic and cultural factors

Social structuring from assortative associations may affect individual fitness, as well as population-level processes. Gaining a broader understanding of social structure can improve our knowledge of social evolution and inform wildlife conservation. We investigated association patterns and community structure of female Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Shark Bay, Western Australia, assessing the role of kinship, shared culturally transmitted foraging techniques, and habitat similarity based on water depth. Our results indicated that associations are influenced by a combination of uni- and biparental relatedness, cultural behaviour and habitat similarity, as these were positively correlated with a measure of dyadic association. These findings were matched in a community level analysis. Members of the same communities overwhelmingly shared the same habitat and foraging techniques, demonstrating a strong homophilic tendency. Both uni- and biparental relatedness between dyads were higher within than between communities. Our results illustrate that intraspecific variation in sociality in bottlenose dolphins is influenced by a complex combination of genetic, cultural, and environmental aspects.

Evidence of male alliance formation in a small dolphin community

The photo-identification of uniquely marked individuals has revealed much about mammalian behaviour and social structure in recent decades. In bottlenose dolphins (Tursiops spp.), for example, the long-term tracking of individuals has unveiled considerable variation in social structure among populations and various spatio-temporal aspects of group formation. In this study, we investigated associations among individual males in a small community of Indo-Pacific bottlenose dolphins (T. aduncus) residing in an urbanized estuary in southwestern Australia. Given the relative proximity of our study area to other populations in which complex male alliances form for the purpose of mate acquisition, we used long-term photo-identification records and social analyses to assess whether such alliances also occur in smaller and more isolated settings. Our work revealed strong social bonds and long-term, non-random associations among individual males, suggesting the occurrence of male alliances. Behavioural observations of alliances interacting with potentially receptive adult females from the estuary community and from adjacent communities, and exhibiting sexual display behaviours near females, suggest that these alliances occur in a reproductive context. As the first formal analysis indicating the occurrence of male alliances outside Shark Bay along the vast western coastline of Australia, this study complements previous research and extends our understanding of the evolutionary and ecological processes that drive alliance formation.

Body length and growth pattern of free-ranging Indo-Pacific bottlenose dolphins off Mikura Island estimated using an underwater 3D camera

Body length and growth pattern of free-ranging Indo-Pacific bottlenose dolphins off Mikura Island estimated using an underwater 3D camera

Prevalence of Skin Lesions and Injuries in Australian Humpback Dolphins (Sousa sahulensis) and Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) in Moreton Bay, Queensland

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 &lt; 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.

Observations on the glycosylation of the term placenta of the Indo-Pacific Bottlenose Dolphin (Tursiops aduncus): A lectin histochemical study

IntroductionLittle is known about the glycosylation of placental villi and areolae of cetaceans. Term tissue from the delivered placenta of an Indo-Pacific Bottlenose Dolphin (Tursiops aduncus) was examined using lectin histochemistry to compare trophoblast glycosylation in these two locations. MethodsPlacental blocks fixed in 10% formalin were resin-embedded before semithin sections were stained with 24 biotinylated lectins and an avidin-biotin revealing system. ResultsAreolar trophoblast was composed of large, bulbous cells packed with numerous granules compared to the smaller, cuboidal cells clothing the chorionic villi, which had a sparser, mainly subapical granule population. Both were richly glycosylated; generally areolar cells were more heavily stained apart from poor binding to some N-acetylgalactosamine and N-acetylglucosamine termini. Most striking was the distribution of α1,2-linked fucosyl residues, weakly expressed in villous trophoblast but intensely stained in some areolar cells, also terminal sialic acids. Some lectins bound in a variable fashion. Staining of terminal α-d-mannose, which locates mainly to lysosomes, was heavy in areolar cells compared to scattered irregular foci in villous cells. Discussion and conclusionThe many intracellular inclusions reflect ongoing lysosomal breakdown of histotroph in areolar cells which often show heterogeneous glycosylation staining unlike the uniformly stained villous cells, possibly reflecting partial breakdown of ingested sialoglycoprotein, cell turnover or regional variation in uptake of histotroph. Our results indicate that Dolphin areolae are functionally distinct from villous trophoblast, performing absorptive and phagocytic functions similar to other Artiodactyla.

Evidence that Indo-Pacific bottlenose dolphins self-medicate with invertebrates in coral reefs

SummaryIndo-Pacific bottlenose dolphins (Tursiops aduncus) have been observed queueing up in natural environments to rub particular body parts against selected corals (Rumphella aggregata, Sarcophyton sp.) and sponges (Ircinia sp.) in the Egyptian Northern Red Sea. It was hypothesized that the presence of bioactive metabolites accounts for this selective rubbing behavior. The three invertebrates preferentially accessed by the dolphins, collected and analyzed by hyphenated high-performance thin-layer chromatography contained seventeen active metabolites, providing evidence of potential self-medication. Repeated rubbing allows these active metabolites to come into contact with the skin of the dolphins, which in turn could help them achieve skin homeostasis and be useful for prophylaxis or auxiliary treatment against microbial infections. This interdisciplinary research in behavior, separation science, and effect-directed analysis highlighted the importance of particular invertebrates in coral reefs, the urgent need to protect coral reefs for dolphins and other species, and calls for further vertebrate-invertebrate interaction studies.

Human food provisioning impacts the social environment, home range and fitness of a marine top predator

Food provisioning promotes close interaction with wildlife but can negatively impact the targeted species. Repeated behavioural disruptions have the potential to negatively impact vital rates and have population level consequences. In Bunbury, Western Australia, food-provisioned female bottlenose dolphins, Tursiops aduncus , suffer reduced reproductive success via lower calf survival. However, the proximal causes of this long-term negative effect remain unknown. To infer processes that could lead to fitness costs, we combined network analyses, Markov Chain, regression models and kernel density estimates to evaluate the social environment, behavioural budget and home range size of provisioned dolphins relative to their nonprovisioned counterparts. We found that provisioned dolphins spent significantly less time socializing and had smaller home ranges and weaker social associations than the nonprovisioned dolphins. Overall, these findings suggest that provisioned dolphins experience a more restricted social environment among themselves, which likely results from investing time in an unnatural foraging tactic around the provisioning site, in proximity to human activities. This modified social environment associated with food provisioning and begging behaviour, reinforced by the limited time spent socializing, could affect the opportunities of calves of provisioned females to acquire fitness-enhancing skills and form essential social bonds. This study highlights the need to consider the potential impact of human activities on the social environment of animals. • Food provisioning is associated with low reproductive success of dolphins. • Food-provisioned dolphins have smaller home ranges and spend less time socializing. • Provisioned females have weaker and ephemeral social connections. • Differences in sociality could be the proximate cause of food-provisioning impact.

Allied male dolphins use vocal exchanges to “bond at a distance”

Vocal interactions are intrinsic features of social groups and can play a pivotal role in social bonding.1,2 Dunbar's social bonding hypothesis posits that vocal exchanges evolved to "groom at a distance" when social groups became too large or complex for individuals to devote time to physical bonding activities.1,3 Tests of this hypothesis in non-human primates, however, suggest that vocal exchanges occur between more strongly bonded individuals that engage in higher grooming rates4-7 and thus do not provide evidence for replacement of physical bonding. Here, we combine data on social bond strength, whistle exchange frequency, and affiliative contact behavior rates to test this hypothesis in wild male Indo-Pacific bottlenose dolphins, who form multi-level alliances that cooperate over access to females.8-10 We show that, although whistle exchanges are more likely to occur within the core alliance, they occur more frequently between those males that share weaker social bonds, i.e., between core allies that spend less time together, while the opposite occurs for affiliative physical contact behavior. This suggests that vocal exchanges function as a low-cost mechanism for male dolphins that spend less time in close proximity and engage in fewer affiliative contact behaviors to reinforce and maintain their valuable alliance relationships. Our findings provide new evidence outside of the primate lineage that vocal exchanges serve a bonding function and reveal that, as the social bonding hypothesis originally suggested, vocal exchanges can function as a replacement of physical bonding activities for individuals to maintain their important social relationships.

Semantic segmentation-based whistle extraction of Indo-Pacific Bottlenose Dolphin residing at the coast of Jeju island

Passive acoustic monitoring (PAM) is commonly utilized to monitor cetacean species’ distribution, abundance, and behavior. The demand for automated methods to detect and extract cetacean vocalizations from acoustic data has increased in the last few decades. Automatic whistle extraction of Indo-Pacific Bottlenose Dolphin (IPBD) and other whistle-producing delphinids habitating in the coastal areas represents a challenging problem due to the high ambient noise, including ship noise snapping shrimp at the same habitat. The acoustic signal containing snapping shrimp sound was usually excluded during the development of the detection method. A robust tool of bioacoustics for snapping shrimp sound is still lacking. This study trained a convolutional neural network (CNN) designed for semantic segmentation, initially developed for autonomous driving, to extract the whistle contour from spectrogram at a pixel level. A total of 1600 datasets was annotated for training and testing. As a result, the semantic segmentation classified the whistle with an overall mean Precision of 0.96, Accuracy of 0.89, and F-score of 0.86. In particular, the semantic segmentation extracted the whistle even if associated with a rich snapping shrimp sound, which the conventional method is incapable of. The advancement of metrics presented in this paper will enable long-term assessment of the IPBD population and individual or group tracking.