Life history and population structure of Beryx decadactylus (Teleostei: Berycidae) in the western North Atlantic
Beryx decadactylus (red bream) is a deep-sea benthopelagic fish with a circumglobal distribution on insular and continental slopes and seamounts. It is commercially exploited together with its congener B. splendens, and catch rates for both species have declined. Limited biological information for management of red bream is available from a few studies conducted around the Azores and, where species data are unavailable for management, biological parameters are assumed to the similar to those of B. splendens. In the United States, red bream is caught incidentally in the wreckfish (Polyprion americanus) fishery which operates off the southeast coast. The aim of this study was to determine the life history parameters of the local red bream population and investigate its genetic stock structure in the North Atlantic. Specimens sampled from the wreckfish fishery ranged from 410 to 630 mm fork length, and were all determined to be mature through gonad histology. Females in spawning condition were observed from June - September, while males were found to be in spawning condition year-round. Sectioned otoliths were difficult to interpret, but age estimates were much higher than previously reported from whole otoliths. Ages ranged from 9 to 69 years, with a mean age of 30 years, and ages of some older fish were verified by bomb radiocarbon analysis. These new insights into the longevity of red bream signify higher vulnerability to overfishing than previously assumed. Analysis of the mtDNA control region showed that eastern and western North Atlantic populations are genetically identical (Œ¶ST = -0.003), suggesting that there is transatlantic gene flow occurring through passive drift of larvae or adult migration. The potential of a shared stock between the eastern and western North Atlantic will need to be considered if a directed fishery for red bream should develop in the United States.
Fishery management; Population genetics; Beryx