ELLSWORTH — The fate of the shrimp fishery for the coming year, if any, will likely be determined Friday afternoon when the Northern Shrimp Section of the Atlantic States Marine Fisheries Commission meets to review the 2019 Stock Assessment Update Report and updates from the section’s Summer Survey Work Group and the Northern Shrimp 2019 Summer Survey Results.
The meeting will be held by telephone and interested parties may listen to the proceedings by joining in the conference call or by signing in to a “webinar” on the internet.
To no surprise, the news is not good for shrimp fishermen, or for Northern shrimp.
In 2018, ASMFC regulators extended an existing moratorium on commercial shrimp fishing through 2021. The three-year moratorium was established in response to continuing low numbers of shrimp in the water and to low levels of “recruitment,” a measure of the number of shrimp that survive long enough to enter the fishery.
According to the most recent stock assessment, in 2018 the northern shrimp resource in the Gulf of Maine was depleted, and the size of the spawning stock, shrimp old enough to reproduce, had remained “extremely low” since 2013.
The most recent analysis of 2019 data, prepared by the shrimp section’s technical committee last month, indicated no improvement. Indices measuring abundance — the weight of the entire shrimp population and spawning stock biomass, a measure of shrimp of reproductive age — were at the lowest levels since scientists began collecting data. The recruitment level was the third lowest measured.
Unlike most commercially harvested species found in the Gulf of Maine, northern shrimp are hermaphroditic. They first sexually mature as males at about 1½–2½ years of age, then transform to females at roughly 3½ years of age.
The shrimp spawn in offshore waters beginning in late July and, by early fall, most adult females extrude their eggs onto the abdomen. The egg-bearing females move inshore in late autumn and winter, where the eggs hatch. The newly hatched juveniles remain in coastal waters for about a year before moving offshore.
Most females spawn only once, but some survive and spawn again. It is the egg-bearing females and females that have spawned once and survived that are targeted in the Gulf of Maine fishery. Scientists believe that few northern shrimp survive past age 5 in the Gulf of Maine.
There was a time when the shrimp fishery was big business in Maine.
During the 1996 season, fishermen landed some 8,100 metric tons (about 1.8 million pounds) of shrimp, worth about $12.9 million, in Maine ports. With landings in New Hampshire and Massachusetts, the total shrimp catch was about 9,500 metric tons.
Less than a decade ago, in 2010, Maine shrimp landings topped 5,700 metric tons worth some $6.7 million to Maine fishermen. Things took a downward turn after that season, which was already shortened by 28 days because of the high catch rates and landings of small shrimp during the spring.
The season was closed early in 2011 and shortened again in 2012 and 2013 as landings exceeded the shrinking total allowable catch (TAC) established by regulators and stock assessments showed the shrimp resource to be exceedingly low.
A moratorium was imposed in 2014, and extended last year through 2021, that allowed for a tiny research fishery by a handful of trawlers and trappers. On Friday, regulators may decide whether the moratorium should be extended.
There appears to be little reason for optimism about a rebound for shrimp which need cool water temperatures to thrive, especially when they hatch in the spring and spawn in late summer.
The water temperature in the Gulf of Maine continues to rise. Winter sea surface temperatures in Boothbay Harbor averaged about 33.4 degrees Fahrenheit during the first half of the 20th century but rose to some 38 degrees during the last decade and was slightly warmer last winter.
Deep water temperatures have shown similar increases. According to the technical committee report, spring bottom temperature changes measured relative to a standard time period in offshore shrimp habitat areas have been above average in recent years. Average summer bottom temperature was just below 42 degrees Fahrenheit from 1984-1993, but increased more than 44 degrees between 2013 and 2019. The mean summer bottom temperature this year was almost 45 degrees, far above the long-term average.
The Northern Shrimp Section conference call is scheduled from 1 to 3 p.m. on Friday. To join the call, phone (888) 585-9008 and enter the passcode 635-498-111. To listen on a computer, go to global.gotomeeting.com/join/651526893.