Strandings as indicators of marine mammal biodiversity and human interactions off the coast of North Carolina

Byrd, Barbie L.; Hohn, Aleta A.; Lovewell, Gretchen N.; Altman, Karen M.; Barco, Susan G.; Friedlaender, Ari S.; Harms, Craig A.; McLellan, William A.; Moore, Kathleen T.; Rosel, Patricia E.; Thayer, Victoria G.

doi:10.7755/fb.112.1.1

Cited by 39 publications

(42 citation statements)

References 52 publications

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“…Harbour porpoises occurred frequently offshore of Maryland from January to May. Consistent with our findings on their seasonal occurrence in the southern part of their range, strandings of porpoises after entanglement in fishing nets occurred primarily from January to May along the shores of Maryland, Virginia, and North Carolina [72, 89]. Scheduling wind farm construction activities in the Maryland WEA to take place during the summer months (June to September) would reduce the likelihood of disturbance to harbour porpoises.…”

Section: Discussionsupporting

confidence: 85%

Year-round spatiotemporal distribution of harbour porpoises within and around the Maryland wind energy area

et al. 2017

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Offshore windfarms provide renewable energy, but activities during the construction phase can affect marine mammals. To understand how the construction of an offshore windfarm in the Maryland Wind Energy Area (WEA) off Maryland, USA, might impact harbour porpoises (Phocoena phocoena), it is essential to determine their poorly understood year-round distribution. Although habitat-based models can help predict the occurrence of species in areas with limited or no sampling, they require validation to determine the accuracy of the predictions. Incorporating more than 18 months of harbour porpoise detection data from passive acoustic monitoring, generalized auto-regressive moving average and generalized additive models were used to investigate harbour porpoise occurrence within and around the Maryland WEA in relation to temporal and environmental variables. Acoustic detection metrics were compared to habitat-based density estimates derived from aerial and boat-based sightings to validate the model predictions. Harbour porpoises occurred significantly more frequently during January to May, and foraged significantly more often in the evenings to early mornings at sites within and outside the Maryland WEA. Harbour porpoise occurrence peaked at sea surface temperatures of 5°C and chlorophyll a concentrations of 4.5 to 7.4 mg m-3. The acoustic detections were significantly correlated with the predicted densities, except at the most inshore site. This study provides insight into previously unknown fine-scale spatial and temporal patterns in distribution of harbour porpoises offshore of Maryland. The results can be used to help inform future monitoring and mitigate the impacts of windfarm construction and other human activities.

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Section: Discussionsupporting

confidence: 85%

Year-round spatiotemporal distribution of harbour porpoises within and around the Maryland wind energy area

et al. 2017

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“…Stranding events are an important resource for identifying threats to marine populations, particularly human-mediated hazards (Wilkinson 1991, Geraci 2005, Carretta et al 2009, Bogomolni et al 2010, Van Houtan et al 2016). Strandings may indicate or reveal sudden, short-or long-term climatic shifts (Schumann et al 2013, Truchon et al 2013, Cavole et al 2016; changes in trophic dynamics (Estes et al 1998, Leopold et al 2015; contamination of prey from pathogens or harmful algal blooms (HABs, Scholin et al 2000, Miller et al 2002, 2010a, b, Torres de la Riva et al 2009, Van Houtan et al 2014; and fishing gear entanglement, boat strikes, or other anthropogenic trauma (Wendell et al 1986, Herrick and Hanan 1988, Hatfield et al 2011, Moore et al 2013, Byrd et al 2014. Because each of these may pose different levels of risk in space and time, or affect different demographic groups, standardized characterization of strandings and systematic data analyses are critical to identifying and managing threats to a population's status.…”

Section: Introductionmentioning

confidence: 99%

Gaps in kelp cover may threaten the recovery of California sea otters

et al. 2018

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Despite more than a century of federal protection, the California sea otter Enhydra lutris nereis remains threatened under the U.S. Endangered Species Act (ESA), and the population has not appreciably expanded its range in two decades. Here, we examine a novel dataset of 725 sea otter live strandings from 1984-2015 to gain insights into demographic and environmental factors underlying threats to sea otter recovery. Using multinomial logistic regression to evaluate spatiotemporal patterns of stranding causes, we demonstrate that increases in stranding rates, particularly outside the range center, are related to a substantial increase in shark bites. By contrast, trauma linked to human activities has declined dramatically, and now accounts for less than 5% of stranding cases. Within the range core, where the sea otter population seems regulated by prey availability, symptoms of energetic stress represent more than 63% of all strandings and are strongly associated with high sea otter density. Conversely, in range peripheries, the majority of strandings are caused by shark bite and neurological disease. Notably, these threats are virtually absent where nearshore habitat is characterized by at least 10% kelp canopy cover. Our analyses reveal that declining kelp cover may therefore constrain the population's spatial expansion and recovery in two key ways. Absence of kelp intensifies density-independent threats in the range peripheries, and likely limits dispersal of reproductive females, which depend on kelp canopy for nursery habitat. These results highlight the significance of both top-down and bottomup processes in population dynamics, and inform an ecosystem-based approach to conservation planning.

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“…Although kogiids are some of the most commonly stranded pelagic cetaceans along the U.S. mid‐Atlantic coast (Byrd et al . ), most aspects of their basic biology and ecology remain unknown. This information deficit is, in part, due to their deep diving habits and offshore distribution (Caldwell and Caldwell , Barros and Duffield , reviewed by Piscitelli et al .…”

Section: Discussionmentioning

confidence: 99%

Prevalence and anatomic site ofCrassicaudasp. infection, and its use in species identification, in kogiid whales from the mid‐Atlantic United States

Keenan-Bateman

McLellan

Harms

et al. 2016

Marine Mammal Science

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The parasitic nematode Crassicauda sp. was initially described in kogiid whales from specimens collected within cervical tissues, uncommon sites of infection for this parasite. Crassicauda sp. has only been reported in Kogia breviceps to date, but no study has yet investigated a large sample of both kogiid species. A 15 yr record of 104 kogiid strandings (K. sima, n = 40; K. breviceps, n = 64) in North Carolina and Virginia, U.S.A. was used to determine the prevalence of Crassicauda sp. across species, within species across sex, and within sex across length and life history categories. Crassicauda sp. was confirmed to be a species‐specific parasite among kogiids infecting only K. breviceps (prevalence = 45%). Within K. breviceps, prevalence was similar (45%) in both immature and mature males, but increased from 10% in immature to 76% in mature females. This study confirmed the cervico‐thoracic distribution of the parasite, and identified a novel site of infection in a previously undescribed exocrine gland associated with the pigmented “false gill slit.” The species‐specific nature of Crassicauda sp. infection, the exocrine gland, and the distinct features of the false gill slit pigmentation associated with the gland, are all useful characters to identify kogiid species in the field.

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Strandings as indicators of marine mammal biodiversity and human interactions off the coast of North Carolina

Cited by 39 publications

References 52 publications

Year-round spatiotemporal distribution of harbour porpoises within and around the Maryland wind energy area

Year-round spatiotemporal distribution of harbour porpoises within and around the Maryland wind energy area

Gaps in kelp cover may threaten the recovery of California sea otters

Prevalence and anatomic site ofCrassicaudasp. infection, and its use in species identification, in kogiid whales from the mid‐Atlantic United States

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