Black Sea Bass

Black sea bass are small (<10 lbs.) structure-dependent fish, which support important commercial and recreational fisheries throughout the Mid-Atlantic and in southern New England.

Black sea bass abundance in the northern end of its range has skyrocketed in the last several years.  This may be due to warming waters that have come with climate change, the maturation of a banner 2011 year-class, or simply be the sort of expansion that comes from stock rebuilding.  But currently, black sea bass are now plentiful as far north as the Gulf of Maine.

Black sea bass are the northern representatives of a group of fish most common in tropical and subtropical waters; thus, it should come as little surprise to learn that their range extends from the Gulf of Maine all the way to the Gulf of Mexico.  Northern and Southern fish have been separated into two distinct stocks, with the demarcation line being Cape Hatteras, North Carolina.

While the South Atlantic Fishery Management Council manages the southern stock, the northern stock is jointly managed by the Mid-Atlantic Fishery Management Council and the Atlantic States Marine Fisheries Commission.

Habitat and Biology

 Black sea bass like structure.  While black seabass certainly aren’t restricted to such areas, anglers generally bottom-fish for black seas bass on or near wrecks, rocky reefs or other hard bottom.  With the expansion of the stock, however, they are now often encountered and caught over non-descript bottom by anglers jigging for striped bass and/or bluefish.

Black sea bass show distinct seasonal movements.  They are abundant inshore during spring, summer and fall, yet inhabit deeper offshore structure during the winter.

Black sea bass reach a maximum size of about 24 inches and a maximum age of about 12 years.  Spawning seems to occur throughout the inshore season but is concentrated during May and June in the Mid-Atlantic and during July and August in New England.

Like a handful of other reef-dwelling fish in southern climates, they are hermaphrodites, having evolved to change sex as they grow older.  They are “protogynous,” meaning that while most are born as females, the majority of those will morph into males as they grow older and larger.

Some fish will change into subordinate males with few distinguishing features; a smaller number will transform into dominant males, characterized by bright, radiant blue and a protruding forehead hump.  These dominant males mate with a harem of younger, smaller fecund females while the subordinate males will mate to a lesser extent by sneaking in and out of the dominant male’s harem.

Such sex-changing characteristics are exclusive to a handful of reef fish around the world, and yet the evolutionary benefits are not quite understood.  This unique life history makes management more complicated as scientists do not fully know what sort of impacts fishing, which presumably removes the more aggressive dominant males, might have on spawning and stock size.  Studies have currently shown that fishing pressure can actually decrease the age of transition from female to male.

Management

The Mid-Atlantic Council has managed back sea bass since 1997 when it amended the Summer Flounder and Scup Fishery Management Plan (FMP) to include black sea bass.

The Council and the Atlantic States Marine Fisheries Commission work cooperatively to develop fishery regulations for black sea bass from Maine to Cape Hatteras, NC. These two fishery management bodies developed a cooperative management approach for black sea bass because a significant portion of the catch is taken from both state waters (0-3 miles offshore) and federal waters (3-200 miles offshore, also known as the Exclusive Economic Zone or EEZ).

The Council’s Scientific and Statistical Committee (SSC) recommends annual Acceptable Biological Catch (ABC) levels for black sea bass based on the most recent and best available science, which are then approved by the Council and Commission and submitted to NOAA Fisheries for final approval and implementation.

The Council develops coast-wide regulations for the recreational black sea bass fishery in federal waters, including a minimum size, a possession limit, and open seasons. The Commission and member states develop recreational black sea bass regulations in state waters.

Stock Status

The northern stock of black sea bass was designated as overfished in 2000.  As part of the Magnuson-Stevens Act’s rebuilding requirements, fishery managers started developing a strategy to rebuild the stock in 2000.

By 2009, the stock was declared rebuilt after a 2008 stock assessment indicated that it was not overfished and overfishing was not occurring in 2007.

The peer review panel approved the assessment for management use, with the caveat that because of the stock’s unique biology (i.e. protogynous hermaphrodite) there was considerable uncertainty as to stock status. The panel recommended that the Council allow for the sizeable uncertainty buffer when establishing catch limits.

A stock assessment update was completed in July 2012, using data through 2011. The results indicated that the black sea bass stock was still not overfished and overfishing was not occurring in 2011. The 2011 stock was estimated to be at 102% of a scientifically determined spawning stock biomass target.

That assessment failed to pass review and was not deemed acceptable for management use.  The Council’s SSC did not adopt the Overfishing Limit derived from this assessment, because of the above mentioned uncertainty involved in managing a protogynous hermaphrodite.

Finally, a 2017 benchmark stock assessment, based on a new model, found black sea bass was not at an overfished level, nor was it experiencing overfishing.

To account for the species’ unique lifecycle, the new assessment defined total spawning stock biomass as the total of male and female mature biomass, which accounts for changes in sex ratio.

The recent assessment passed peer-review in December, yet reviewers still recommended precaution as the existence of one particularly good year class (2011) – one particular year of good spawning – characterizes recent abundance, and fishing effects on a protogynous hermaphrodite are still relatively unknown.

Commercial and Recreational Fisheries

 The commercial allocation is 49% of the total allowable catch in the form of a hard quota.  The recreational sector gets 51% in the form of a recreational harvest target.

Commercial fisheries change with changes in seasonal distribution of the resource.  The spring, summer and fall inshore fishery is generally prosecuted with pots and handlines.  When fish move offshore in the winter they are primarily caught in trawl fisheries targeting summer flounder, scup and longfin squid.  Such non-directed trawl fisheries generally account for around 70% of the commercial fishery.

Black sea bass support a sizable recreational fishery in the Mid-Atlantic. Most directed recreational black sea bass fishing occurs in state waters when the fish migrate inshore during the warm summer months.  They are also caught frequently by anglers targeting summer flounder over hard bottom.

At one time, there was also an active winter fishery for black sea bass, which was generally prosecuted from party boats in the upper Mid-Atlantic, and from party, charter and private boats farther south.

However, because NOAA Fisheries does not collect recreational harvest data in the Mid-Atlantic states during January and February, and because black sea bass caught during those months are brought up from deep water and generally suffer trauma from the pressure change making them nearly impossible to successfully release, the Mid-Atlantic Fishery Management Council, at its November 2012 meeting, decided to prohibit black sea bass fishing at that time of year.

Chronic Recreational Overages

While commercial landings have been very close (within 2%) to the commercial quota over the last five years, the recreational black sea bass fishery has exceeded harvest target every single year since 2012.

However…  such recreational overages occurred when the black sea bass abundance had been rapidly expanding and availability to recreational anglers had been very high, primarily due to an exceptionally strong 2011 cohort entering an already fully rebuilt stock that was aggressively expanding its range into northern waters.

In addition, because the 2012 stock assessment did not pass peer-review, the recreational harvest targets were set at low levels because of the high degree of scientific uncertainty in the stock assessment; such low annual harvest limits did not reflect the large and increasing numbers of black sea bass available to anglers.

The new 2017 benchmark stock assessment analysis indicates that recreational harvest targets during the last few years would have been significantly higher (approximately double those implemented) if they had been set using the new peer-reviewed stock assessment model, and overages would likely not have occurred… at least not to the same degree.

In other words, catch limits have not kept pace with increasing stock abundance.

The new stock assessment more accurately reflects such abundance, and allows a whopping 52% increase in the annual catch limit for 2017.  Yet, because of substantial recreational overharvest in 2016, the 2017 recreational regulations will likely remain similar to 2016.  Beginning in 2018, the big 2011 year class will begin to disappear from the fishery, and unless another large year class is already in the pipeline, catch limits will again decline.

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