Persistent Effects of Begging on Common Bottlenose Dolphin (Tursiops truncatus) Behavior in an Estuarine Population

Hazelkorn, Rebeccah A.; Schulte, Bruce A.; Cox, Tara

doi:10.1578/am.42.4.2016.531

Cited by 11 publications

(11 citation statements)

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“…However, several studies have reported opportunistic feeding (begging) around fishing vessels, in contrast with the current results. Begging was mainly observed around trawlers (Genov et al ., 2008; Hazelkorn et al ., 2016; Kovacs et al ., 2017). In the Istanbul Strait, purse seines are the legal fishery practices, while trawling is illegal.…”

Section: Discussionmentioning

confidence: 99%

Encounter rate, residency pattern and site fidelity of bottlenose dolphins (Tursiops truncatus) within the Istanbul Strait, Turkey

Bas

Öztürk

2018

J. Mar. Biol. Ass.

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The Istanbul Strait is an important cetacean habitat that is intensely used by humans. Yet little is known about their spatial-temporal distribution. To understand the encounter rates and residency patterns of bottlenose dolphins, photo-identification data were collected between 2011 and 2016 in the Istanbul Strait. The study showed that bottlenose dolphins are a regular, year-round component of the strait. The encounter rate was estimated to be four groups (22 individuals) per 10 km. The adjacent waters of Marmara Sea and Black Sea, that host relatively less marine traffic, had the highest number of encounters in the area. Conversely, the middle sections had the lowest number of encounters but the highest marine vessel density. Further, the encounter rates dropped to zero in the fishing zones, where the number of purse seines reached up to 100 per day. Additionally, dolphins showed varying degrees of residency patterns, with multi-year re-sightings. Maximum re-sighting distance was up to 35 km, which is more than the total length of the strait. This movement pattern should be investigated as it might reveal possible migration between local populations. This study finds that the Istanbul Strait serves as a critical habitat for the regional bottlenose dolphin populations and they are likely to be a part of a resident local population with a home range extending the length of the strait. Dedicated surveys with inter-regional collaborations are needed to evaluate the home range and population status of this endangered species for their effective conservation in one of the busiest waterways of the world.

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Section: Discussionmentioning

confidence: 99%

Encounter rate, residency pattern and site fidelity of bottlenose dolphins (Tursiops truncatus) within the Istanbul Strait, Turkey

Bas

Öztürk

2018

J. Mar. Biol. Ass.

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“…Four studies showed increased degree between "human-associated foragers", or animals that obtain food via anthropogenic pathways. Human-associated foraging has been seen in at least 25 different marine mammal species [40] such as California sea lions (Zalophus californianus), common bottlenose dolphins (Tursiops truncatus), and botos (Inia geoffrensis) removing fish from gillnets; rough-toothed dolphins (Steno bredanensis), and killer whales (Orcinus orca) stealing hooked fish, sperm whales depleting long-lines [41], and bottlenose dolphins following trawl nets to forage for prey [40,42,43] or begging from human vessels for food handouts [44,45,46,47,48]. Human-associated foragers aggregated near human food sources, which increased their connections with other human-associated foragers, and their risk of exposure to pathogens.…”

Section: Behavioral Competencementioning

confidence: 99%

“…Because not all individuals in a population participated in human-associated foraging, group-level connectivity was affected. Typically, humanassociated foragers displayed behaviors that are highly specialized for small communities [42,48,43,53,54]. As a result, human-associated foragers were shown to have unique group sizes and habitat preferences [55], resulting in little interaction with "natural" foragers.…”

Section: Behavioral Competencementioning

confidence: 99%

Impacts of human disturbance in marine mammals: Do behavioral changes translate to disease consequences? Full methods and Analysis

Collier¹,

Ali²,

Mann³

et al. 2020

Preprint

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Humans have been altering wildlife habitats and wildlife behavior worldwide at an accelerated pace in recent decades. While it is well-understood how human-induced behavioral changes affect infectious disease risk in terrestrial wildlife, less is known in marine life. Here we examine this link in marine mammal populations by (1) conducting a systematic literature review to determine how human disturbances change marine mammal behavior in ways that can impact disease spread, and (2) examining how these behavioral changes might influence potential epidemics using a mathematical modeling framework. We find that human disturbances can influence marine mammal behavior in a way that increases their exposure and susceptibility to pathogens, as well as their infectivity, or ability to effectively shed pathogens and infect conspecifics. When these changes to exposure, susceptibility, and infectivity are applied in four different marine mammal case studies, epidemics are predicted to be larger and more likely to occur. Considering the rate at which human disturbance is increasing in the marine environment, and the large number of marine mammal species that are endangered oron the verge of extinction, we advocate for the careful consideration of the direct and indirect impact of human disturbance on marine mammal health.

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“…Short-term responses show behavioral changes, such as, lengthened dive intervals, increased swimming speed, fewer resting periods, and changes in acoustic behavior (Bas et al, 2017;Bejder & Samuels, 2003;Lusseau, 2003Lusseau, , 2004Lusseau & Higham, 2004;Stockin et al, 2008). However, short-term behavioral changes exhibited by cetaceans can be difficult to extrapolate into population impacts (Williams et al, 2006) compared to long term consequences that may include increased injury and mortality rates as a result of vessel strikes, bycatch, and entanglement (Consiglio et al, 1992;Defran & Weller, 2006;Hazelkorn et al, 2016;Stockin et al, 2008).…”

mentioning

confidence: 99%

“…T. truncatus are opportunistic feeders and have been found to associate with trawlers during the retrieval of gill nets, having displayed evidence of net depredation (Au, 1993;Hazelkorn et al, 2016;Pace et al, 2003;Perrin et al, 1994), highlighting the behavioral plasticity of T. truncatus to take advantage of anthropogenic activity (Pace et al, 2003).…”

mentioning

confidence: 99%

The effect of commercial and artisanal fishing practices on the behavioral budget of bottlenose dolphins off the coast of Montenegro, South Adriatic Sea

Rudd

Awbery

Waller

et al. 2022

Marine Mammal Science

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The spatial–temporal distribution of cetacean species often overlaps with fishing practices in the Mediterranean, having direct and indirect consequences. This is the first long‐term study focusing on the effects of fisheries on the behavior of T. truncatus in Montenegro. Focal group scan sampling was used during surveys between September 2016 and August 2020 to create transition probability matrices using first‐order Markov chains for behavioral states in both control (absence of fishery practices) and impact chains (presence of fishery practices). Despite the low number of dolphin‐fishery interactions in Montenegro, results revealed that the behavioral budgets of T. truncatus were significantly altered both for commercial and artisanal fisheries. However, the magnitude of the threat differed between practices, with commercial fisheries altering three out of the four behaviors in the behavioral budget while artisanal fisheries altered just one. Significant behavioral changes due to disturbance can have negative consequences on the energy budget of individuals and while the Montenegrin fishing fleet is currently limited to 224 vessels, the significant effects already witnessed are concerning for Montenegrin bottlenose dolphins. To develop in‐situ mitigation strategies, there is a clear need to better understand the impact that fisheries interactions have on these individuals.

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Persistent Effects of Begging on Common Bottlenose Dolphin (Tursiops truncatus) Behavior in an Estuarine Population

Cited by 11 publications

References 0 publications

Encounter rate, residency pattern and site fidelity of bottlenose dolphins (Tursiops truncatus) within the Istanbul Strait, Turkey

Encounter rate, residency pattern and site fidelity of bottlenose dolphins (Tursiops truncatus) within the Istanbul Strait, Turkey

Impacts of human disturbance in marine mammals: Do behavioral changes translate to disease consequences? Full methods and Analysis

The effect of commercial and artisanal fishing practices on the behavioral budget of bottlenose dolphins off the coast of Montenegro, South Adriatic Sea

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