MEPS 212:217-222 (2001)  -  doi:10.3354/meps212217

Spatial and temporal scales of patches of crab larvae in coastal waters

Cecily C. Natunewicz*, Charles E. Epifanio

University of Delaware, Graduate College of Marine Studies, 700 Pilottown Rd, Lewes, Delaware 19958, USA

ABSTRACT: This study examined the spatial and temporal scales of patches of crab larvae in the coastal waters of the Middle Atlantic Bight near the mouth of Delaware Bay, USA (38.70°N, 75°W). The spatial scale of the patches was characterized by sampling along-shelf and across-shelf transects via series of continuous plankton tows. Autocorrelation of larval densities along each transect revealed that patch diameters ranged from about 0.5 to 2.5 km in both along-shelf and across-shelf dimensions. The ages of 12 different patches were estimated by comparing the proportions of Stage I and Stage II larvae composing each patch. One additional patch was tagged with a satellite-tracked drifter, and changes in the proportions of the 2 stages were observed over a 3 d period. Analysis indicated that the tagged patch had remained cohesive for at least 4 d and possibly as long as 6 d. Potential mechanisms for patch formation and maintenance include synchronous spawning events, associative larval behavior, and aggregative physical processes.

KEY WORDS: Patch · Transport · Larvae · Callinectes sapidus · Delaware Bay

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