The status of the Delaware whelk dredge fishery was assessed from state landings reports and from data collected by an onboard observer. Mean annual whelk landings for 1994 to 2000 were 18.5 mt of meats and increased to 241.6 mt for the period 2001 to 2004. Annual landings for 2001 to 2003 were 88% to 119% of the sum of dredge and trawl fishery landings reported by the remaining states on the United States Atlantic coast. Although knobbed whelks, Busycon carica, are landed throughout the year, 88% of pooled monthly landings for 1994 to 2004 were taken between March and June inclusive. Eleven observer cruises were conducted March to June 2004. Total estimated daily take of legal (length ≥127 mm) knobbed whelks ranged from to 197–3,710 organisms. Expected catch rates were estimated at 83.2 legal knobbed whelks per hour per meter of dredge width. Dredges were generally towed parallel to bathymetric contours and adjacent to shoal features in 2–20 m depths. Estimates of the area of bottom dredged on each cruise ranged from 4.9–14.2 ha. At times, multiple boats were observed dredging the same bottom, suggesting a cooperative fishing technique. Seventy-nine percent of dredge tows occurred on bottom comprised of mud and sand, and mean numbers of knobbed whelks in 0.04 m3 samples were greatest from mud/sand habitats. Twenty-one taxonomic groups of organisms were observed in samples taken from dredges. Knobbed whelk and horseshoe crabs, Limulus polyphemus, dominated dredge catch by number. Whelks collected in the Atlantic Ocean were significantly larger than those collected in the Delaware Bay. Mean lengths of whelks collected in the Bay in 2004 were significantly less than lengths of Bay whelks collected in 1994 prior to the inception of the minimum length regulation. Shifts in size distribution and the cyclical nature of other whelk fisheries suggest that the elevated landings experienced during 2001 to 2004 are not sustainable.
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Vol. 25 • No. 1