Browsing by Author "Eckert, Scott"

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    An Analysis of Utilizing the Leatherback’s Pineal Spot for Photo-identification
    (2008-04-20T02:16:26Z) Buonantony, Danielle
    Leatherbacks are one of the most endangered species of sea turtles. Their global population size had decreased dramatically over the past several decades. Difficulties in applying long-term marking methods on leatherbacks, have significantly hindered our ability to generate an accurate population estimate and to track population changes on the scale of individuals. External marking methods are plagued by high rates of tag loss which compromise the utility of tagging as a means of long-term identification. While having substantially better retention rates, the high cost PIT tags and the specialized equipment necessary to detect them, have limited the expansion of this technique. This project outlined the need for innovative approaches to identifying turtles and sought to resolve some of the issues plaguing traditional tagging protocols by reinvestigating the feasibility of using photo-identification to recognize individual leatherbacks. Pioneering studies of pink spot photo-identification by McDonald and Dutton (1996) showed that the pineal spot of the leatherback is distinct enough to be used as a unique identifier. This research investigated whether individual turtles could be recognized by their “pink spot” when a large sample (~400) was drawn from a very large nesting population (~ 3,000 nesting annually). It also sought to determine whether identification could be automated using photo-identification software. The results indicated that the pineal “pink” spot’s form has sufficient variation to be used as a unique identifier in photo-identification studies. Using the Scale Invariant Feature Transform (SIFT) function we were able to successfully automate identification. Through a cascade filtering approach the program was able to achieve one hundred percent matching accuracy, while eliminating the possibility of false negatives. Further studies are required to examine the degree of deviation that may occur within the pink spot over time, and to refine our methodologies to expand the use of this method amongst leatherback researchers.
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    Bycatch Mortality of Leatherback Turtles in Trinidad's Artisanal Gillnet Fishery
    (2006) Gass, Jordan
    Although listed globally as critically endangered, leatherback turtles maintain a strong nesting population in Trinidad. Trinidad supports an estimated population of 6,000 nesting females, which despite increased beach protection still face significant risk in the form of coastal gillnets. Incidental captures also impact fishers, who incur financial losses in reduced fishing time from net damage and associated repair costs. During the 2005 nesting season, my project used fisher participation in villages in the northeast region of Trinidad to attempt to measure bycatch levels. The methods used to quantify bycatch are described and results discussed. Challenges encountered during the project are also assessed to plan modifications of project methods to enhance fisher participation and confidence in results.
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    Diving Behavior of Female Loggerhead Turtles (Caretta caretta) During Their Internesting Interval and an Evaluation of the Risk of Boat Strikes
    (2008-12-05T14:42:14Z) Sobin, Jacob
    New advantages in science and technology, such as time depth recorders (TDRs), have allowed researchers to study the dive behavior of sea turtles in their natural habitats. Observing dive behavior of internesting turtles has provided significant evidence on how to protect nesting turtles from human interactions. One source of anthropogenic mortality on marine turtles is boat strikes. Trend data from the Florida Sea Turtle Stranding Network demonstrate that the annual proportions of boat-strike related mortality is increasing. Since 1980 boat strike injuries have tripled in Florida. This study, near Casey Key Beach in southwest Florida, examined the internesting dive behavior of loggerhead sea turtles using time-depth-recorders; National Geographic Crittercamstm, and satellite-linked location data to evaluate the risk of boat impacts based on the resulting dive data. When combined with 4 years of satellite telemetry data gathered prior to this study I revealed that loggerhead turtles are most vulnerable to boat strikes between 8 a.m. – 12 p.m. on the day following a nesting or false crawl event and on the night before returning to the beach to nest. Potential mitigation measures, such as spatial and temporal boat restrictions, are reviewed by this study.
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    Essential Fish Habitat in Santa Monica Bay, San Pedro Bay, and San Diego Bay: A Reference Guide for Managers
    (2006) Robbins, Erika A.
    The Sustainable Fisheries Act established as one of its mandates for regional fishery management councils and the National Marine Fisheries Service a requirement to identify and protect Essential Fish Habitat. The Act defines Essential Fish Habitat as “those waters and substrates necessary to fish for spawning, breeding, feeding and growth to maturity.” 16 U.S.C. § 1802(10). To promote the protection of Essential Fish Habitat, the Act establishes interagency consultation between the National Marine Fisheries Service and federal agencies that fund, authorize, or undertake action that may adversely affect Essential Fish Habitat. For their part in the interagency consultation process, the National Marine Fisheries Service is required to provide Essential Fish Habitat Conservation Recommendations, and, if appropriate, in an expedited manner. The time required to develop proper Essential Fish Habitat Conservation Recommendations can be extensive because managers do not always have access to sufficient information and the scale of Essential Fish Habitat descriptions is larger than the scale of most projects. To facilitate accurate abbreviated assessment of projects and proper Essential Fish Habitat Conservation Recommendations, I have developed an Essential Fish Habitat Reference Guide. This guide is specific to the fish and habitats found in Southern California’s three largest bays: Santa Monica Bay, San Pedro Bay, and San Diego Bay. I synthesized the information contained within this guide from documents traditionally used to support the creation of Essential Fish Habitat Conservation Recommendations. Managers can use the Essential Fish Habitat Reference Guide for interagency consultations when the predicted impact to Essential Fish Habitat is minimal; actions with larger impacts need higher levels of scrutiny. The Reference Guide provides habitat and Essential Fish Habitat descriptions that are on the same, or similar scale, as the projects of federal action agencies. The Habitat Conservation Division of the National Marine Fisheries Service Southwest Regional Office has used draft versions of this guide.
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    Evaluating the Effectiveness of Marine No-Take Reserves in St. Eustatius, Netherlands Antilles
    (2009-04-24T17:20:05Z) McClellan, Katherine
    Marine reserves, in which exploitation of marine organisms and other human activities are restricted or prohibited, can be valuable tools for marine conservation and fisheries management. No-take marine reserves support greater density, size, and diversity of fishes than exploited areas, with most benefits accruing to heavily exploited species. Protected areas can also export biomass to sustain or increase the overall yield of adjacent fisheries. These effects can be especially significant for organisms with small home ranges, such as coral reef fish. Although there are many benefits to creating marine reserves they are also costly to manage and can infringe on people’s recreation and livelihoods. For marine reserves to be used as management tools, a comprehensive knowledge of the ecosystems is needed and reserve impacts should be regularly monitored. St. Eustatius Marine Park and two no-take marine reserves were established by the Statian government in 1996 to promote dive tourism and sustainable fisheries. No fisheries study was carried out prior to reserve implementation to determine the status of fish stocks. In the summer of 2008, surveys were undertaken inside and outside the marine reserves to census reef fish and habitat to establish a current baseline and to evaluate the effects of the marine reserves on reef fish populations. The data that was collected was used to answer three questions about the current state of the Marine Park: 1) are there habitat related differences between reserve areas and non-reserve areas or between reef types? 2) do fish density, diversity, or biomass differ between protected and unprotected sites or between reef types? and 3) do habitat characteristics, reserve status, or reef type influence fish density, diversity, and biomass? This study determined that habitat differences among the survey sites affected reef fish populations more than reserve status. However, the no-take reserves may still be important for protecting reef fish populations. The two reserves have been in place for more than 10 years and it is unknown what happened to fish populations during that time. Future research, employing the methods of this study, can be used to monitor reef fish populations and habitat over time to better determine if the reserves are having beneficial effects.
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    Mark-Recapture Estimation of the Leatherback Sea Turtle (Dermochelys coriacea) Nesting Population at Matura Beach, Trinidad
    (2004) Hodge, Christina E
    Many researchers believe that Caribbean leatherback sea turtle (Dermochelys coriacea) populations are increasing. Since Trinidad currently hosts the world’s third largest leatherback nesting assemblage, accurate population estimates are needed for this area. Nature Seekers, Inc., a community-based environmental management organization, has been monitoring leatherback nesting on Matura Beach since 1990 and began its tagging project in 1999. The tagging project’s main goal was to determine the number of turtles nesting each year, but saturation tagging has not been possible given the resources available. However, as a season progresses, untagged turtle encounters constitute a smaller percentage of the overall leatherback encounters. The steady increase in percent of previously tagged turtles encountered during the season indicates that a significant portion of the population is being tagged and makes within season mark-recapture population estimation possible. This project examines the rate of recapture of tagged turtles, trends in the timing of recapture events, and the requirements for mark-recapture estimates of leatherback nesting populations. The probability of encountering an individual leatherback varies based on the time of the season and the number of days since it was last encountered. To account for this variability, each season was divided into cohorts based on a nine day nesting cycle. Closed capture, time dependent population estimates were derived for each cohort using Program Capture. Data from the 2000, 2001, and 2003 nesting seasons yielded mark-recapture population estimates averaging 62 percent greater than the minimum number of turtles encountered. This is consistent with the 40 percent beach coverage estimate provided by Nature Seekers at the initiation of this analysis. The 20 to 24 day average time between encounters of individual leatherbacks also supports the theory that Nature Seekers observes slightly less than half of the nesting events on Matura Beach since leatherbacks are known to nest every nine to ten days. Developing models to estimate sea turtle populations in situations where saturation tagging is not possible is critical for determining the status of endangered leatherback sea turtles. Future efforts should be directed toward improving nesting beach coverage, developing more accurate tagging effort indices, examination of the degree of nesting beach population closure, and the development of leatherback encounter probability models.
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    National Parks Conservation Association Natural Resource Assessment for Fort Pulaski National Monument
    (2007-05) DiMatteo, Andrew
    As a national monument, much of the focus at this park is on cultural heritage rather than natural resources. However, this park is home to 5,000 acres of near pristine wetland as well several hundred more acres of upland and aquatic habitat. Using the methodology laid out by the National Parks Conservation Association Center for the State of the Parks, a qualitative assessment of the natural resources at this park was performed. This was accomplished by performing an extensive literature review at the park, with state and federal data providers, and with National Park Service Regional Inventory and Monitoring offices. Interviews with park staff and, to a limited extent, on-site inspections occurred. These data were used to assign scores of 0-3 (0 being irreparably damaged, 3 being pristine) to various natural resource categories. The sum of these categories was then used as an overall indicator of park health. The park was found to be in vulnerable condition overall.
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    National Parks Conservation Association State of the Parks Report: Natural Resource Assessment Cumberland Island National Seashore, Camden County, Georgia
    (2007) Laliberté, Jennifer
    The National Parks Conservation Association through their Center for the State of the Parks (NPCA-SOTP) is currently performing natural resource assessments of the nation’s national parks. As a part of this program, I was contracted to do a natural resource assessment of Cumberland Island National Seashore (CUIS) in Camden County, Georgia. CUIS is a barrier island located off the coast of Georgia just north of the Florida border. It has been subject to anthropogenic use for at least 4000 years, with major occupations beginning with the arrival of the Spainards in the 1500s. After changing hands several times, the island became the property of the National Park Service in 1972 (16 U.S.C. 459i et seq) under the authority of the National Parks Organic Act of 1916. CUIS also includes a Congressionally-designated wilderness area that was established in 1982 (16 U.S.C. 1131 et seq.) under the authority of the Wilderness Act of 1964. There are 18 retained-rights estates within the boundaries of the seashore, as well as 2 tracts of land that are still held as private property. The management regime for the park includes a general management plan that was published in 1984. There is currently a new management plan being drafted for the park, which includes management policies for cultural resources, natural resources, and the wilderness area. A fire management plan was published in 2004, and dictates the allowance of natural fires except where humans or buildings are threatened. CUIS maintains good habitat structure with the exception of a few areas that were modified over the years of human use, including modifications made for agriculture and the presence of several buildings. Some of the modified areas are being allowed to regain their natural state, while some areas are preserved by the NPS as cultural landscapes. The structure and function of the island’s ecosystems have changed in response to anthropogenic pressure and the introduction of feral species, mainly hogs and horses, continues to have a profound effect upon the island’s ability to recuperate. The periods of human occupation also resulted in the extirpation of all of the island’s top predators, including black bears and bobcats. This likely has resulted in an alteration of fundamental predator-prey processes. The primary recommendations for natural resource management within the park include an immediate reduction of the feral horse population, ideally confining the remaining individuals to the southern end of the park, continuing the hog eradication program, and regulating human visitation to the island, particularly the arrival of visitors to the island via personal watercraft. Impacts to the island should be considered and mitigated as the surrounding areas of Camden County are developed. Finally, increased monitoring and funding to Cumberland Island’s natural resource program are critical to understanding and mitigating current and future impacts.
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    Sustainability Certification in Community-based Fisheries
    (2005) Fetherston, Elizabeth H.
    Mismanagement of global fisheries resources has an overwhelmingly negative effect on the survival of community-based fisheries. In developing countries, community based fishing is a socially as well as economically valuable activity providing much needed employment and income in areas where there are few alternatives for either. In order to promote sustainability in these areas, the World Wildlife Fund for Nature (WWF) and the Marine Stewardship Council (MSC) are attempting to apply their sustainable seafood ecolabeling program to community-based fisheries. The MSC and WWF examined ten community-based fisheries in 2000, including Prainha do Canto Verde, a fishing village in northeastern Brazil. Though the community harvested lobster in a sustainable manner, the larger fishery did not. The national lobster fishery in Brazil covers over 150,000 square kilometers and is characterized by illegal, unsustainable fishing practices and poor enforcement. As a result, the lobster stock remains in serious decline and faces the possibility of collapse. This failing stock health prevented the MSC from considering Prainha do Canto Verde for sustainability certification. Under the MSC, a sustainable product can never come from an unsustainable fishery, despite pockets of good management and environmentally responsible practices. Currently, the MSC is powerless to promote sustainable practices in communitybased fisheries because the criteria relate directly to the sustainability of the product. By certifying small-scale communities that harvest sustainably within an admittedly unsustainable system, economic incentives for other communities to change their behavior could develop, to the benefit of the larger fishery. Recognizing the constraints inherent in the MSC, this project proposes alternative approaches to promoting the welfare of communities and the sustainability of their fisheries.