Sex and maturity of black sea bass collected in Massachusetts and Rhode Island waters; preliminary results based on macroscopic staging of gonads with a comparison to survey data

This information is distributed for the purpose of predissemination peer review. It has not been formally disseminated by NOAA. It does not represent any final agency determination or policy. Introduction Black sea bass (Centropristis striata) are protogynous hermaphrodites, with most individuals maturing first as a female before changing sex to male later in life (Wenner et al 1986). This life history characteristic poses unique challenges for management of the species (Shepherd and Nieland 2010), and requires accurate information/understanding of the sex ratios and the size at which sex changes. Several studies have described salient aspects of black sea bass life history, however these have largely been limited to populations in the South Atlantic Bight (SAB) and Although black sea bass north of Cape Hatteras, NC are considered part of a single fishery management unit, focused life history studies on more northern portions of the population are lacking. Given greater migration distances and larger sizes attained by the northern stock component 'borrowing' of data from southern populations may be inappropriate. To reduce uncertainties in management of this population requires accurate estimate of sex ratios and size at sexual transition for this population. The need for more current and detailed (histology based) life history information for the northern component of the stock is currently being addressed in a cooperative research funded project ('A histology-and otolith-based study of black sea bass (Serranidae: Centropristis striata) life history in southern New England', Dr. K. Oliveira, R. Jorgensen UMASS Dartmouth). However, the scheduling of SARC53 necessitates reporting preliminary data to address questions about sex ratios of black sea bass in the northern management unit. Specifically, there is an apparent conflict of this species characterized as a protogynous hermaphrodite but that small and young males are evident in the NEFSC groundfish survey database. Namely, how likely are these small males misspecified by macroscopic methods used in routine survey operations? This working paper documents in detail the macroscopic method of identifying sex and maturity class of black sea bass, and although it does note that criteria for identifying active sex change needs further clarification, it also confirms that small males in survey data are real and should be accounted for in modeling of sex ratios. Methods Fish were obtained from two sources; the Massachusetts Division of Marine Fisheries (MA-DMF) inshore trawl survey (spring, May; and fall, September) and Research Set Aside (RSA) funded fishery independent scup survey of …