Browsing by Subject "strandings"

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Open Access
An Analysis of Gray and Harbor Seal Strandings in Cape Cod, Massachusetts from 1999 to 2012.
(2014-04-25) Frungillo, Jaime
In recent years, the number of gray seals, Halichoerus grypus, inhabiting Massachusetts has increased dramatically. In Canada and Scotland, similar increases in gray seal abundance have been accompanied by a concomitant decrease in numbers of sympatric harbor seals, Phoca vitulina. It has been hypothesized, although not confirmed, that interspecific competition between the two species led to a decrease in harbor seal populations. The present study addressed the question of whether gray seals and harbor seal populations are interacting in Cape Cod, MA by analyzing stranding data from Cape Cod in the period from 1999 to 2012, provided by the International Fund for Animal Welfare (IFAW). Gray seal strandings increased 2.9% annually from 1999 to 2012. Harbor seal strandings, on the other hand, increased 8.5% annually until 2004, after which the increased stopped and the number of strandings varied interannually. Strandings were best predicted by species, age class, and month, although age class only affected harbor seal seasonal stranding trends. Seasonal trends in the number of gray and harbor seal strandings caused by human interactions were significantly different. These differences in the stranding record suggest that the two species are interacting ecologically in Cape Cod.
Open Access
Assessment of Sea Turtle Rehabilitation in North Carolina
(2019-04-26) Stevens, B
As is the case with all sea turtle species, the five species that occur within North Carolina waters are listed as either threatened or endangered under the Endangered Species Act of 1973. Due to their endangered/threatened status, rehabilitation efforts are key for their long-term conservation since the release of healthy individuals helps promote more sustainable populations. In order to ensure rehabilitation efforts are concentrated properly and to assess their success rates, in-depth studies must be done on the stranding records available for each rehabilitation facility within the state. While other states such as Florida and Queensland, Australia have conducted studies to determine their rehabilitation characteristics and success rates, a comprehensive study of a similar nature has never been done with the sea turtle rehabilitation records for the state of North Carolina. This study analyzes the rehabilitation records for the state of North Carolina to determine the most common characteristics of sea turtles admitted for rehabilitation as well as the successful release rates over time. Sea turtle rehabilitation efforts and record keeping began at the North Carolina Aquariums back in the mid-1980s which was soon followed by the opening of the Karen Beasley Sea Turtle Rescue and Rehabilitation Center in 1997. The North Carolina Aquarium on Roanoke Island partnered early with the Network for Endangered Sea Turtles (N.E.S.T.) which eventually became the Sea Turtle Animal Rescue(STAR) Center in 2014. Both the North Carolina Aquariums and the KBSTRRC largely outsourced any necessary veterinary care through a collaboration with North Carolina State University’s College of Veterinary Medicine though the North Carolina Aquariums hired its first full-time veterinarian for sea turtle care in 2015. This study reviews the rehabilitation records of North Carolina to date, presented as two datasets taken from the public North Carolina Aquariums and the private, non-profit Karen Beasley Sea Turtle Rescue and Rehabilitation Center (KBSTRRC). A total of 2707 rehabilitation records were available which was narrowed down to 2594 records for data analysis after a variety of factors including the restriction of the time period used to only include those records from January 1997 to October 2018. Characteristics were determined for the majority of rehabilitation records such as: life stage, sex, stranding causation, stranding location, species, rehabilitation location, rehabilitation outcome, and release location. The successful rate of release was determined and compared against studies done in Florida and Queensland, Australia for comparative purposes. Based on the 2707 records available, both life stage and sex were removed as variables in future data analysis due to skewed proportions for turtles in their juvenile life stage as well as those that did not have their sex determined during rehabilitation. When looking at the restricted 2594 records, the most common sea turtle brought in for rehabilitation in North Carolina was a green sea turtle species, stranded in inshore waters (landward of the Coast Guard’s COLREGS line) due to cold stunning, and successfully released. The most common rehabilitation facility used was the North Carolina Aquarium on Roanoke Island and its affiliates followed by the Karen Beasley Sea Turtle Rescue and Rehabilitation Center, and the North Carolina State University’s College of Veterinary Medicine based in the Center For Marine Sciences and Technology (CMAST). When compared to the other studies looked at, the successful release rate for North Carolina was nearly double the successful release rates seen in both Florida and Queensland, Australia. The results discussed in this study will help rehabilitation facilities in North Carolina better tailor resources and funds to accommodate the most commonly seen characteristics as well as provide a baseline to be compared against for future data analysis within North Carolina, other states, or when looking specifically at one rehabilitation facility.
Open Access
Bycatch and Biomass: Mitigating dolphin bycatch while maintaining fish catch in the Virginia Beach pound net fishery
(2008-04-18T22:24:11Z) Herman, Elia
Pound nets are traditional, passive fishing traps that have been used since the 1870s to catch estuarine fish species in the Chesapeake Bay. Most unwanted species captured in the actual pound net can be released alive; however, sea turtles and marine mammals may die if they become entangled in the leader of the net. In 2004, NOAA Fisheries required changes in the construction of pound net leaders in part of the Chesapeake Bay to reduce entanglement rates of sea turtles. To date no actions have been taken to address the bycatch of bottlenose dolphins in pound net leaders. In the summer of 2007, I conducted a pilot study to sample catches of butterfish (Peprilus alepidotus and Peprilus triacanthus) and Spanish mackerel (Scomberomorus maculatus) in a Virginia Beach pound net fishery considering modifications to their leaders to reduce dolphin bycatch. Using these observations, I worked with the Virginia Aquarium to design an experiment to test the new leaders during the 2008 fishing season. The primary goal of this experiment is to determine whether the experimental leader will affect the catch of target fish species. From an analysis of dolphin strandings in Virginia from 1997-2004, I found that pound nets accounted for the greatest percentage (50%) of all documented Human Interaction (HI) strandings. I also used geospatial analyses to examine the distribution of bottlenose dolphin strandings that may be associated with bycatch in pound nets. HI stranded dolphins were found significantly closer to the Virginia Beach pound nets than dolphins that stranded for another reason (No HI) or for an unknown cause (CBD). Together these analyses help to improve our understanding of interactions between bottlenose dolphins and the Virginia Beach pound net fishery, as well as the importance of community-based management efforts.