Behavioral responses to fishing line entanglement of a juvenile bottlenose dolphin in Shark Bay, Australia

Miketa, Madison L.; Krzyszczyk, Ewa; Mann, Janet

doi:10.19185/matters.201711000011

Cited by 7 publications

(10 citation statements)

References 29 publications

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“…Dolphins are thus likely to remain in the system as long as adequate resources are available. However, abnormal dolphin mortality was not observed during the course of this study or by a contemporary study of mother–calf pairs (Miketa ), making it difficult to explain the declines observed here. While dolphins in Shark Bay forage on seagrass‐associated fishes, they are less dependent on seagrass for forage than cormorants or sea snakes (Heithaus and Dill , Heithaus , Sargeant et al.…”

Section: Discussioncontrasting

confidence: 65%

“…, Miketa ). For example, a contemporary study in Shark Bay indicated that while seagrass associated dolphins used seagrass habitats more frequently after the heat wave, they reduced their foraging time in heavily damaged beds, instead foraging in relatively intact seagrass habitats (Miketa ). Similarly, cormorants in this system track prey densities even at fine, microhabitat scales (Heithaus ), and cormorants were more likely to use shallow habitats after the seagrass die‐off.…”

Section: Discussionmentioning

confidence: 98%

“…However, reductions of absolute food supply may be offset somewhat by increased teleost density in remaining vegetated habitats post‐die‐off (R. Nowicki et al., unpublished data ), and through reduced refuge for teleosts and increased echolocation and foraging efficiency in newly denuded habitats (Wilson et al. , Miketa ). For example, a contemporary study in Shark Bay indicated that while seagrass associated dolphins used seagrass habitats more frequently after the heat wave, they reduced their foraging time in heavily damaged beds, instead foraging in relatively intact seagrass habitats (Miketa ).…”

Section: Discussionmentioning

confidence: 99%

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Indirect legacy effects of an extreme climatic event on a marine megafaunal community

Nowicki

Heithaus

Thomson

et al. 2019

Ecological Monographs

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While extreme climatic events (ECEs) are predicted to become more frequent, reliably predicting their impacts on consumers remains challenging, particularly for large consumers in marine environments. Many studies that do evaluate ECE effects focus primarily on direct effects, though indirect effects can be equally or more important. Here, we investigate the indirect impacts of the 2011 “Ningaloo Niño” marine heatwave ECE on a diverse megafaunal community in Shark Bay, Western Australia. We use an 18‐year community‐level data set before (1998–2010) and after (2012–2015) the heatwave to assess the effects of seagrass loss on the abundance of seven consumer groups: sharks, sea snakes (multiple species), Indo‐pacific bottlenose dolphins (Tursiops aduncus), dugongs (Dugong dugon), green turtles (Chelonia mydas), loggerhead turtles (Caretta caretta), and Pied Cormorants (Phalacrocorax spp.). We then assess whether seagrass loss influences patterns of habitat use by the latter five groups, which are under risk of shark predation. Sharks catch rates were dominated by the generalist tiger shark (Galeocerdo cuvier) and changed little, resulting in constant apex predator density despite heavy seagrass degradation. Abundances of most other consumers declined markedly as food and refuge resources vanished, with the exception of generalist loggerhead turtles. Several consumer groups significantly modified their habitat use patterns in response to the die‐off, but only bottlenose dolphins did so in a manner suggestive of a change in risk‐taking behavior. We show that ECEs can have strong indirect effects on megafauna populations and habitat use patterns in the marine environment, even when direct effects are minimal. Our results also show that indirect impacts are not uniform across taxa or trophic levels and suggest that generalist marine consumers are less susceptible to indirect effects of ECEs than specialists. Such non‐uniform changes in populations and habitat use patterns have implications for community dynamics, such as the relative strength of direct predation and predation risk. Attempts to predict ecological impacts of ECEs should recognize that direct and indirect effects often operate through different pathways and that taxa can be strongly impacted by one even if resilient to the other.

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Section: Discussioncontrasting

confidence: 65%

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

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Indirect legacy effects of an extreme climatic event on a marine megafaunal community

Nowicki

Heithaus

Thomson

et al. 2019

Ecological Monographs

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“…Overall, the SAOM framework enables to study how individuals change their relationships in response to the present network structure, i.e., group behavior ( 29 ). Despite its strong potential, SAOMs have been less explored in animal studies compared to social sciences studies [barbary macaques: ( 26 ); black-capped chickadees: ( 30 ); bottlenose dolphins: ( 31 ); crickets: ( 27 , 32 ); farmed salmons: ( 33 ); fruit flies: ( 34 ); rooks: ( 35 ); spiders: ( 36 ); spotted hyenas: ( 24 ); vervet monkeys: ( 37 )].…”

Section: Introductionmentioning

confidence: 99%

Understanding Allogrooming Through a Dynamic Social Network Approach: An Example in a Group of Dairy Cows

et al. 2020

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For gregarious species such as domestic cattle, the social environment is a very important determinant of their welfare and fitness. Understanding the complexity of cows' relationships can assist the development of management practices that are more integrated with the cows' social behavioral processes. The two aims of this study were: (1) to determine the dynamics of affiliative relationships, as indicated by allogrooming, by means of stochastic actor-oriented modeling, in dairy cows during early lactation; (2) to explore the underlying processes and the individual attributes, such as age, social rank and reproductive state, that could shape network pattern changes in grooming contacts between individual. We observed the allogrooming behavior of a dynamic group of 38 dairy cows for 4 h per day for 30 days. Using stochastic actor-oriented models, we modeled the dynamics of weekly contacts and studied how structural processes (e.g., reciprocity, transitivity, or popularity) and individual attributes (i.e., age, social rank, and reproductive state) influence network changes. We found that cows tended to groom individuals that had previously groomed them, implying a possible cooperation. Cows that groomed more actively did not appear to have a preference for specific individuals in the herd, and in return, tended to be groomed by fewer cows over time. Older individuals groomed more cows than younger ones, indicating that allogrooming could be related to seniority. Cows groomed mainly individuals of similar age, suggesting that familiarity and growing up together enhanced social grooming. Over time, cows with higher social rank were groomed by fewer cows and individuals recently reintroduced to the group groomed more herdmates. The study of social network dynamics can be used to better understand the complexity and non-linearity of cow relationships. Our findings, along with further research, can complement and strengthen the design of improved management practices that are more in line with the natural social behavior of cows.

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“…Observations of a bottlenose dolphin calf temporarily entangled in monofilament line showed immediate alterations in the behavior of the mother and calf, as well as conspecifics ( 71 ). A similar pattern of seemingly social avoidance by conspecifics following entanglement has occurred on a number of occasions [( 72 ) and references therein], where the costs of entanglement (e.g., infection, injury, energetic costs, inability to forage), are likely exacerbated. As well as causing distress to surviving family or social group members, the loss of key individuals may lead to the loss of important social knowledge ( 73 ).…”

Section: Welfare Impacts Associated With Bycatchmentioning

confidence: 77%

Sustainable Fisheries Management and the Welfare of Bycaught and Entangled Cetaceans

Dolman¹,

Brakes

2018

Front. Vet. Sci.

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The incidental capture of cetaceans and other protected marine wildlife in fishing gear has significant welfare implications. Many thousands of cetaceans are bycaught in fishing gear in European waters and hundreds of thousands die globally. We can expect many more to survive, but suffer from such interactions. As marine policy focuses on “population level” impact assessments and “sustainability” of fishing to preserve fish populations, the impacts to the bycaught individual, and their wider social group, are often largely underestimated, despite the large numbers affected. The wide range of recorded injuries, including abrasions, cuts, bruising, and broken bones, along with the potential for panic associated with forced submersion, indicate that the welfare of bycaught cetaceans is, individually and collectively, very poor. Commercial fishing is the last human activity targeting wildlife (fish) on a grand scale where slaughter includes incidental killing of other large sapient wildlife on such a regular basis. Here, we review the compelling evidence of the short and long term welfare impacts of bycatch, and the progress made toward implementation of measures to understand and solve this significant welfare issue. We argue that policy decisions surrounding fishing do not adequately consider cetacean bycatch, including welfare impacts. Ultimately, there are welfare issues in all bycatch situations and suffering cannot plausibly be reduced without preventing bycatch. The well-documented welfare implications provide a strong argument for zero tolerance of cetacean bycatch and provide a compelling case for immediate action in fisheries where bycatch is taking place. The only way to reduce the suffering of bycaught cetaceans is to decrease, or ideally eliminate, the number of animals caught in fishing gear. Uncertainties around the scale of bycatch should not delay management, even where individual bycatch estimates are considered “sustainable.” Lack of monitoring of sub-lethal impacts on populations may result in flawed impact assessments. We urge that animal welfare considerations should become an integral part of management decision-making in relation to bycatch globally. Enhanced, robust and transparent management systems are urgently required for the range of fisheries within which cetacean bycatch occurs, with the aim to better document and most importantly, work toward eliminating cetacean bycatch altogether.

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Behavioral responses to fishing line entanglement of a juvenile bottlenose dolphin in Shark Bay, Australia

Cited by 7 publications

References 29 publications

Indirect legacy effects of an extreme climatic event on a marine megafaunal community

Indirect legacy effects of an extreme climatic event on a marine megafaunal community

Understanding Allogrooming Through a Dynamic Social Network Approach: An Example in a Group of Dairy Cows

Sustainable Fisheries Management and the Welfare of Bycaught and Entangled Cetaceans

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