Summary:
Due to the lack of data concerning horseshoe crab populations, this three-part project has been undertaken to obtain information concerning
demographic distribution of horseshoe crabs, effect of blood extraction on horseshoe crab survival, and to examine migration patterns and long-term survival of bled horseshoe crabs.
Description:
This master's project has been divided into three components, each with its own main goal.
Component 1
involves the tagging of horseshoe crabs bled by BioWhittaker, the largest producer of LAL. As originally mandated by the Atlantic States Marine Fisheries Commission (ASMFC), 2,500 horseshoe crabs will be tagged each summer following the blood extraction process as performed by BioWhittaker. Information for each tagged crab including gender, age, and size is recorded and maintained in a database by the United States Fish and Wildlife Service (USFWS). Re-sighted crabs are reported to USFWS, and from these reports, information concerning movement patterns and long-term survival of horseshoe crabs will be obtained.
Component 2
involves the collection of demographic data for horseshoe crabs. Throughout the course of three field seasons (Summer 1999, Summer 2000, and Summer 2001), demographic samples of horseshoe crabs obtained by BioWhittaker in trawls of the Atlantic Ocean will be examined. These samples will be analyzed to compare the age, size and sex distributions of horseshoe crabs caught in BioWhittaker's trawling processes both spatially and temporally. Fluctuations in these distributions across the various locations BioWhittaker obtains horseshoe crabs as well as over the course of three field seasons will be examined.
Component 3
involves the estimation of the effect of BioWhittaker's blood extraction process on survival of horseshoe crabs. In this part of the project, groups of bled and not-bled crabs are maintained in tanks at Virginia Tech's Seafood and Agricultural Research Center in Hampton, Virginia. Differences in mortality rates between the two groups are examined. Initial results show a 15% increased mortality in bled horseshoe crabs as compared to not-bled horseshoe crabs. This third component will quantify the impact of biomedical use of horseshoe crabs on horseshoe crab populations.