ATLANTIC SPOTTED DOLPHIN (Stenella frontalis): Western North Atlantic Stock

• Main Authors: Stock Definition, Geographic Range
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2000
• Subjects: Payne; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.228.8025; http://www.nefsc.noaa.gov/nefsc/publications/tm/tm182/pdfs/233.pdf

There are two species of spotted dolphin in the Western Atlantic — the Atlantic spotted dolphin, Stenella frontalis, formerly S. plagiodon (Perrin et al. 1987), and the pantropical spotted dolphin, S. attenuata. These species are difficult to differentiate at sea. Atlantic spotted dolphins are distributed in tropical and warm temperate waters of the western North Atlantic (Leatherwood et al. 1976). Their distribution is from southern New England, south through the Gulf of Mexico and the Caribbean to Venezuela (Leatherwood et al. 1976; Perrin et al. 1994). The large, heavily spotted form of the Atlantic spotted dolphin along the southeastern and Gulf coasts of the United States, which may warrant designation as a distinct sub-species (Rice 1998), ( inhabits the continental shelf, usually being found inside or near the 200 m isobath (within 250-350 km of the coast) but sometimes coming into very shallow water adjacent to the beach (Figure 1). Off the northeast USA coast, spotted dolphins are widely distributed on the continental shelf, along the continental shelf edge, and offshore over the deep ocean south of 40 o N (CETAP 1982). Atlantic spotted dolphins regularly occur in the inshore waters south of Chesapeake Bay and near the continental shelf edge and continental slope waters north of this region (Payne et al. 1984; Mullin in review). Sightings have also been made along the north wall of the Gulf Stream and warm-core ring features (Waring et al. 1992). Stock structure in the western North Atlantic is unknown. POPULATION SIZE Total numbers of Atlantic spotted dolphins off the USA or Canadian Atlantic coast are unknown, although three estimates from selected regions of the habitat do exist for select time periods. Because S. frontalis and S. attenuata are difficult to differentiate at sea, the reported abundance estimates, prior to 1998, are for both species of spotted dolphins combined. Sightings were almost exclusively in the continental shelf edge and continental slope areas west of Georges Bank (Figure 1). ...