Is There a ‘Cryptic Biomass' of Relatively Old and Large Red Snapper in Southeast US Continental Shelf-Break Waters?

Recent assessments of red snapper (Lutjanus campechanus) in southeastern US Atlantic (hereafter SEUS) waters have indicated that the stock is overfished, leading to closure of the fishery by the South Atlantic Fishery Management Council.  One criticism of the assessments, made by members of the recreational and commercial fishing industries, is that fisheries managers have not considered a ‘cryptic biomass’ of relatively old and large red snapper in continental shelf-break waters off northeastern Florida and Georgia that (1) was not effectively targeted by any fishing industry sector prior to the closure, due to gear restrictions and high current speeds in those areas, and (2) has not been effectively surveyed in fishery-independent sampling programs.  We describe a cooperative effort between scientists and commercial fishers to test explicit hypotheses regarding spatial variation in red snapper age, size and abundance patterns in SEUS waters.  Contracted commercial fishers used industry-standard longline gear, standardized across all samples, to survey red snapper across three depth zones and eight latitudinal bands off northeastern Florida and Georgia.  A total of 218 red snapper were collected during the survey, with otolith-derived ages ranging from 3 to 15 years and sizes ranging from 48 to 96 cm total length.  Results indicated considerable spatial variation in red snapper age and size distributions, and in catch-per-unit-effort (CPUE).  However, results were not supportive of the ‘cryptic biomass’ hypothesis, as there was no evidence of greater ages, sizes or CPUE values in shelf-break waters.  In contrast, generally higher proportions of older and larger fish and greater CPUE values occurred in shallower, continental shelf waters.  These results suggest that a new fishery-independent longline survey would provide limited additional information for monitoring red snapper in SEUS continental shelf-break waters.