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Start of the Fourth Season of Caribbean Reef Shark Study

April 22, 2011

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April 4, 2011 marked the start of the fourth season of the Caribbean reef shark offshore research project at the Cape Eleuthera Institute. The day began at 6:45 am, packing the boat with necessary equipment, bait and tools for a full day of field research on the water. A team of four headed three nautical miles southeast of Cape Eleuthera to a sampling area known as ‘zone four’, where the oceanic shelf drops off dramatically. This interface between shallow mid-bank waters and extreme depths in known as “the wall”. The wall is a popular site for fish aggregations, and therefore, all offshore surveys are set in close proximity to it. After an hour and a half soak time, the team began to haul in the 500m long scientific survey line and its 40 hooks, hoping that at least a few had sharks attached. Just before unclipping the second gangion from the line, a large dark vision approached the surface. The two research advisors on board had gone an entire sampling season last summer without seeing a tiger shark, and were ecstatic when they saw the shark’s characteristic striped markings. Once the team secured the shark alongside the boat, they were able to take length measurements and other important data. The mature male tiger shark’s total length measured 298cm, roughly 10ft. The shark was tagged using a dart tag and cattle tag, and small fin clip was collected for DNA analysis. Once everything was recorded and photographs were taken, the animal was released in good condition, sporting his new tag jewelry. A second survey was conducted at ‘zone three’. The second haul, proved to be another success, yielding our target species, a Caribbean reef shark (Carcharhinus perezi), as well as another slightly smaller tiger shark. The week continued with multiple sets in the mornings and afternoons. The majority of the following survey lines caught no sharks, although several small sharpnose sharks (Rhizoprionodon porosus) were caught. Researchers hypothesize that the low catch rate might be due to the fact that the migratory Caribbean reef shark population has not yet arrived in Cape Eleuthera to mate. The study will continue to be carried out during the first week of every month into the summer, as a part of a four-year long data set. It is hoped that the data acquired through this research will further the information known about spatial and temporal movements of Caribbean reef sharks, through both passive and active tagging methods, as well as calculating a reliable population estimate of the species.

One Comment leave one →
  1. O. C. Branneky permalink
    April 26, 2011 1:20 pm

    This Al Pickaard sure knows how to take action pictures

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