Scientist aboard the NEAMAP SNE/MA Nearshore Trawl Survey with a dominant, male black sea bass as evidenced by the nuchal hump right at the top of its head before its dorsal fin. Photo credit: NEAMAP.
Black sea bass (Centropristis striata) inhabit Atlantic coastal waters from the Gulf of Maine to the Florida Keys, concentrating in areas from Cape Cod, Massachusetts to Cape Canaveral, Florida. Two distinct stocks of black sea bass exist along the Atlantic coast with overlapping ranges. The northern stock migrates seasonally and spawns off of New England in the late summer. A temperate reef fish, black sea bass commonly inhabit rock bottoms near pilings, wrecks, and jetties. Black sea bass rely on their large mouth and swift ocean currents to catch prey, which include fish, crabs, mussels, and razor clams. Black sea bass summer in northern inshore waters at depths of less than 120 feet and winter in southern offshore waters at depths of 240 to 540 feet.
Black sea bass are protogynous hermaphrodites, which mean they start life as a female and when they reach 9-13 inches (2 - 5 years of age) they change sex to become males. Thirty-eight percent of the females in the Mid-Atlantic demonstrate sex reversal between August and April, after most fish have spawned. Even though some fish are males when they reach sexual maturity, most produce eggs when they first mature. Following transition, a sea bass will either become a dominant male, characterized by a larger size and a bright blue nuchal hump during spawning season (see accompanying photo), or a subordinate male that has few distinguishing features.
Black sea bass are highly sought by both commercial and recreational fishermen throughout the Mid-Atlantic. Fisheries change seasonally with changes in fish distribution. Inshore and more southern commercial fisheries are primarily use with fish pots and handlines. When fish move offshore in the winter, they are primarily caught in trawl fisheries targeting summer flounder, scup and Loligo squid. Recreational fisheries generally occur during the period that sea bass are inshore. Since the fishery management plan’s approval in 1997, the black sea bass fishery has operated under a quota. Landing levels for both the commercial and recreational fisheries are restricted by annual total allowable landings.
Commercial landings of black sea bass have been recorded since the late 1800s. From 1887 through 1948, commercial landings north of Cape Hatteras fluctuated around six million pounds and then peaked at 22 million pounds in 1952. Fish were primarily harvested by handlines during the 1900s. The 1950s marked the development of the trap fishery. Otter trawls and fish pots/traps have accounted for the majority of the black sea bass landings in most states. Other important gear includes hand lines and lobster pots. Commercial landings were estimated to be 2.3 million pounds in 2014.
Black sea bass are also an important recreational species in the Mid-Atlantic, commonly caught using squid and natural bait. In 1965, over half of the total catch of black sea bass was credited to recreational fishing. Angling pressure increased markedly in the mid-1980s. In 1998 and 1999, recreational landings decreased substantially relative to levels in the early to mid-1990s. The decrease in recreational landings may be partially attributed to an increase in minimum size limits. Landings started to increase in 2000 and averaged 4 million pounds from 2000 to 2004. Recreational landings in 2014 were estimated at 3.6 million pounds.
The 2012 stock assessment update indicates that black sea bass is continues to be rebuilt; it is not overfished and is experiencing overfishing. Fishing mortality in 2011 is F = 0.21, a decrease from 2010 and well below the fishing mortality threshold of F=0.44. Estimates for 2011 total biomass remain above the biomass maximum sustainable yield. Spawning stock biomass (SSB) in 2011 was estimated to be 24.6 million pounds, below the SSB target of 27.6 million pounds but well above the SSB threshold. Recruitment at age 1 (fish entering the stock) averaged 26.4 million fish during 1968-1999, peaking at 56 million fish in 2001. The 2011 year class was 21 million fish.
The next benchmark stock assessment is scheduled be peer-reviewed through the Northeast Regional Stock Assessment Workshop/Stock Assessment Review Committee in late fall 2016.
Black sea bass is managed jointly by the Atlantic States Marine Fisheries Commission and the Mid-Atlantic Fishery Management Council under Amendment 13 to the Summer Flounder, Scup and Black Sea Bass Fishery Management Plan (August 2002) and its subsequent addenda (Addendum XIII-XXII). The objectives of the FMP are to reduce fishing mortality to assure overfishing does not occur, reduce fishing mortality on immature black sea bass to increase spawning stock biomass, improve yield from the fishery, promote compatible regulations among states and between federal and state jurisdictions, promote uniform and effective enforcement, and to minimize regulations necessary to achieve the stated objectives.
The management program divides a total annual quota between the recreational fishery (51%) and the commercial fishery (49%). Recreational fishery management measures include the same combination of minimum size limits, bag limits and fishing seasons set for the entire coast. The commercial quota is divided into state-by-state quotas annually. Specific management measures for the commercial fishery are set by each state, which may 1) minimum size limits, 2) minimum mesh requirements for trawls or 3) a moratorium on entry into the fishery and closed seasons.
Although the black sea bass fishery was declared rebuilt in 2009, the unique life history characteristics of the species (e.g., it is a protogynous hermaphrodite, which means it changes sex from female to male) contributes to some level of uncertainty about the size of the stock. The response of this species, as well as other hermaphroditic species, to exploitation is not fully understood. Given these concerns, the Commission and the Mid-Atlantic Fishery Management Council approved an accepatble biological catch of 5.5 million pounds. After accounting for projected discards in the commercial and recreational fisheries, this ABC is divided into a commercial quota of 2.24 million pounds and a recreational harvest limit of 2.33 million pounds for the 2016 and 2017 fishing years. Catch levels for 2016 and 2017 are unchanged relative to 2015 levels.