After spending over 50 years on and around the water, I have realized that without strong fisheries laws and effective conservation measures, the future of salt water fishing, and America's living marine resources, is dim. Yet conservation is given short shrift by national angling organizations and the angling press. I hope that this blog will incite, inform and inspire salt water fishermen to reclaim their traditional role as the leading advocates for the conservation of America's fisheries.
Thursday, February 16, 2017
WILL "STEEPNESS" STYMIE OPPONENTS OF FLUKE REGULATIONS
there is one constant in mid-Atlantic fisheries management, it is that
restrictions on the recreational summer flounder harvest will always be
As is typically the case,
those who oppose NMFS’ action are attacking the science that underlies the
agency’s decision to reduce recreational landings. The American Sportfishing
Association (ASA), which represents the fishing tackle industry,claims that“the
decision is being based on an outdated benchmark stock assessment,” whilean article inThe Fishermanmagazinerailed against “‘fatally flawed’ MRIP
data, [and] the inherent issues with NOAA’s trawl survey methodologies,” even
though arecent National Academy
of Sciences reportgave
the Marine Recreational Information Program a very favorable review.
This year the opponents of
fluke regulation are claiming that a new study, prepared by biologists hired by
a group calling itself theSave the Summer Flounder Fishery Fund(SSFFF), justifies their criticism of
the current stock assessment.Such studyfound
that “female summer flounder dominate the recreational catch; however…this does
not hold below the legal size limit. On average, across all ports, dates, and
depths, the sex ratio approximates 50:50 at 39 cm [15.6 inches], with males
dominant in the size classes less than 39 cm and females dominant above 39 cm.”
They use the study to
support the notion, expressed inanotherFishermanarticle written by Nick Cicero,
one of the founders of SSFFF, that “blame must be assigned to any management
strategy that forces us to target spawning class females exclusively. It’s
crazy, we’re talking biological suicide!” To avoid catching so many large
females, opponents of the current regulatory approach suggest that “management
strategies in the recreational fishery in the future should include the
potential for a slot limit fishery” that established both a minimum and maximum
size for fish that may be retained by anglers.
Proponents of such a “slot limit” argue that a slot that allowed
anglers to keep smaller fish, and assure that males made up a significant
portion of the recreational harvest, would better assure that enough large
females survived to maintain the population at a sustainable level.
However, such argument runs afoul of two fisheries management
principles: The need for a closed season to control harvest, and a measure of
stock productivity known as “steepness.”
Season length comes into play because there are only three ways
that fishery managers can limit anglers’ landings: size limits, bag limits,
closed seasons or some combination thereof. As a rule, both anglers and the
businesses they support consider a reasonably long season the most important
management measure because it provides anglers more time to fish, which in turn
results in more money flowing to angling-related businesses. There is no
biological reason for recreational size limits to be as high as they are today;
anglers could enjoy the same 14-inch minimum size that governs the commercial
fishery, if they were willing to accept a much shorter season in exchange.
Proponents of a slot limit seem to forget that if anglers were
allowed to retain smaller “slot” summer flounder (so far, no slot size has been
proposed, but it’s reasonable to assume that any slot would bracket the point
where males and females are equally represented in anglers’ catch), the season
would have to be shortened to compensate for the greater number of legal-sized
fish that would be caught.
And that’s where “steepness” comes in.
Like fishing mortality and
spawning stock biomass, steepness is a parameter that fisheries managers must
consider when setting annual catch limits.NMFS defines it as“the ratio of two recruitment levels;
the recruitment obtained when the spawning stock is at 20% of its virgin level,
and the recruitment at the virgin population level.” It is expressed as a
number between 0 and 1; the lower the number, the more recruitment—the number
of young fish entering the population—is dependent on stock size. A high
steepness number, on the other hand, suggests that good recruitment can occur
even when the spawning stock is relatively small.
Thus, proponents of a slot limit for summer flounder, who use
the SSFFF study to justify their position, are actually contradicting
If the summer flounder population must include a large number of
large females to guarantee good recruitment—that is, if summer flounder
steepness is low—fishing mortality needs to be tightly constrained in order to
maintain the large spawning stock necessary to maintain a healthy population. A
slot limit, without a significantly shortened season, would allow anglers to
kill too many fish.
On the other hand, if steepness is high enough to justify the
higher fishing mortality that would result from a slot limit combined with the
current season, then there is no need to assure that a large number of older
females remain in the population, as good recruitment can result from a small
Whichever scenario turns out to be the right one, neither
justifies a claim that the SSFFF study somehow negates the need to reduce
fishing mortality today.
In fact, current science supports high steepness for summer
Thelast benchmark stock assessmentdetermined that calculations based on
such a high steepness number were “suspect,” and did not consider such figure
in setting the permissible (threshold) fishing mortality rate. But even if the
actual steepness figure for summer flounder is somewhat lower, that figure will
still be high enough to assure fisheries managers that there is no need to
increase the number of females present in the spawning stock.
Although, according to the benchmark assessment, the stock could
actually tolerate a higher fishing mortality rate and smaller target biomass.
Managers determined that “little gain…(<5%) was realized at fishing
mortality rates higher than [the current threshold of] F35%=0.310," while
the current target biomass and threshold fishing mortality rate provided a
"buffer against short-term declines in recruitment," which is exactly
the situation which faces the stock right now.