Preliminary Assessment of a Nearshore Nursery Ground for the Scalloped Hammerhead off the Atlantic Coast of Florida

摘要

This study provides information regarding an open-ocean, nearshore nursery ground for the scalloped hammerhead Sphyrna lewini off the Atlantic coast of Florida near Cape Canaveral. Neonate scalloped hammerheads collected from this region ranged in size from 385 to 500 mm in total length (TL) and were observed during May and June, when water temperatures ranged from 26.1 deg C to 28.8 deg C. Although nearshore gill-net sampling during the study period encompassed the Florida Atlantic coastline from north of Cape Canaveral (latitude 28 deg 40'N) south to the Jupiter Island area (latitude 27 deg 04'N), neonate scalloped hammerheads were collected only in waters near the Cape Canaveral area. The nearshore waters near Cape Canaveral served as a nursery ground for scalloped hammerheads in 1994 and 1997. Extensive fisheries-independent gill-net sampling within the adjacent northern Indian River Lagoon system (Banana River Lagoon and Indian River Lagoon proper) did not collect scalloped hammerheads, indicating that this estuarine area does not serve as a nursery ground for this species. Other shark species collected in the overall study area included juvenile nurse sharks Ginglymostoma cirratum (620-1,219 mm TL); juvenile blacktip sharks Carcharhinus Hmbatus (630-885 mm TL); neonate, juvenile, and adult Atlantic sharpnose sharks Rhizoprionodon termenovae (305-1,000 mm TL); juvenile and adult bonnethead Sphyrna tiburo (430-1,150 mm TL); and neonate and juvenile bull sharks C. leucas (754-1,460 mm TL). Human access to a portion of the open-ocean area near Cape Canaveral is currently prohibited due to security issues at the adjacent National Aeronautics and Space Administration's Kennedy Space Center and Cape Canaveral Air Force Station. This area closurehas inadvertently created a marine reserve by eliminating fishing pressure on and significantly reducing vessel- or shore-based human interaction with this nearshore habitat. The effects, if any, of this marine reserve on shark populations in the regionare unknown, and studies regarding these and other aspects of shark abundance and distribution in the Cape Canaveral area are currently ongoing.