Northern shrimp (Pandalus borealis) is a crustacean located in the cold waters of the Northern Hemisphere. The species is found in Canadian waters and in the northern-most waters of the U.S. On the U.S. Atlantic coast, it primarily inhabits waters off of Maine, New Hampshire, and Massachusetts. Northern shrimp are hermaphroditic, maturing first as males at roughly 2 1/2 years of age and then transforming to females at about 3 1/2 years. Female shrimp may live up to five years old and attain a size of up to three to four inches in length. Differences in size at age by area and season can be ascribed to temperature effects, with more rapid growth rates at higher temperatures. Differences in size at age from year to year, and in size at sex transition, have been attributed to both environmental and stock density effects.
Spawning takes place in offshore waters during the late summer. By early fall, most adult females extrude their eggs onto the abdomen. Egg-bearing females move inshore in late autumn and winter, where the eggs hatch. Northern shrimp are an important link in marine food chains, preying on both plankton and benthic invertebrates and, in turn, being consumed by many important fish species, such as cod, redfish, and silver and white hake.
Historically, northern shrimp have provided a small but valuable fishery to the New England states. The fishery is seasonal in nature, peaking in late winter when egg-bearing females move into inshore waters and ending in the spring under regulatory closure.
The commercial fishery began in earnest in the late 1950s/early 1960s and experienced an incredible expansion in landings, peaking in 1969 at 28.3 million pounds. Over the next decade, landings dropped precipitously to a low of less than 85,000 pounds in 1977. The fishery was closed in 1978 due to a stock collapse. The fishery slowly reopened in 1979 and landings increased steadily to over 11 million pounds by 1987. Landings ranged from 5.1 to 9.7 million pounds during 1988-1994, and then rose dramatically to 20.1 million pounds in 1996, the highest since 1973. Landings declined to an average of 4.2 million pounds for 1999 to 2001, and dropped further in the 25-day 2002 season to 992,250 pounds, the lowest northern shrimp landings since the fishery was closed in 1978. Landings then increased steadily, averaging 4.6 million pounds during the 2003 to 2006 seasons, then jumping to 10.8 million pounds in 2007 and 11 million pounds in 2008. In 2009, 5.5 million pounds were landed during a season that was market-limited. The proposed 180-day season for 2010 was cut short to 156 days with 13.5 million pounds landed, due to the industry exceeding the recommended landings cap for that year, and concerns about small shrimp.
As in 2010, the 2011 season was closed early. The season was scheduled to be 136 days, but was closed after 90 days. A preliminary total of 14.1 million pounds of shrimp were landed, exceeding the recommended limit (4,000 mt) by approximately 8.8 million pounds. In 2012, the season was further restricted, with the trawl fishery beginning on January 2 with 3 landings days per week (Mondays, Wednesdays, and Fridays) and the trap fishery beginning on February 1 with a 1,000 pound limit per vessel per day. The TAC was set at 4.9 million pounds and would close when the projected landings reached 95% of the TAC. The season was closed on February 17, resulting in a 21-day trawler season and a 17-day trap season.
The 2013 season, which was classified as a “do no harm” fishery, resulted in a fishing mortality rate (0.53) above the target (0.38). This was despite the fact that only 49% of the total allowable catch was harvested (676,935 pounds of 1.39 million pounds). Due to recruitment failure and a collapsed stock, moratoria were instituted for the 2014, 2015, and 2016 fishing seasons.
Since the 2014 benchmark stock assessment was not accepted by the peer review panel for management use, the Northern Shrimp Technical Committee evaluated a suite of indicators to determine the status of the stock for 2015. Using these indicators, the Technical Committee found abundance and biomass indices for 2012-2015 were the lowest on record for the 32-year time series. The stock has experience failed recruitment for five consecutive years, including the three smallest year classes on record. As a result, the indices of fishable biomass from 2012-2015 are the lowest on record.
Recruitment of northern shrimp is related to both spawning biomass and ocean temperatures, with higher spawning biomass and colder temperatures producing stronger recruitment. Ocean temperatures in western GOM shrimp habitat have increased over the past decade and reached unprecedented highs in 2011 and 2012. While 2014 and 2015 temperatures were cooler, temperatures are predicted to continue to rise as a result of climate change. This suggests an increasingly inhospitable environment for northern shrimp. The Northern Shrimp Technical Committee considers the stock to have collapsed with little prospect of recovery in the immediate future. The increased abundance of northern shrimp predators (spiny dogfish, redfish and silver hake) may play a role in declining biomass. Northern shrimp stocks in other areas of the world (Greenland, Flemish Cap, Grand Banks) have also seen decreasing trends in abundance and recruitment, providing additional evidence that environmental conditions are impacting northern shrimp across their range.
Northern shrimp, Pandalus borealis (top), and two species of striped shrimp (P. montagui and Dichelopandalus leptocerus bottom). Photo by Cinamon Moffett, University of Maine.
The Commission’s Northern Shrimp Section is comprised of the states of Maine, New Hampshire and Massachusetts. Amendment 2 and its addenda set the management regulations for the Gulf of Maine northern shrimp fishery.
The original Fishery Management Plan was adopted by the Commission in 1986. Amendment 1, implemented in 20014, established biological reference points for the first time in the shrimp fishery and expanded the tools available to manage the fishery. Management of northern shrimp under Amendment 1 resulted in a rebuilt stock and increased fishing opportunities. However, early season closures occurred in 2010 and 2011 because landing rates were far greater than anticipated. Furthermore, untimely reporting resulted in short notice of the season closures and an overharvest of the recommended total allowable catch (TAC).
To address these issues, Amendment 2 (approved in 2011) completely replaces the FMP and provides management options to slow catch rates throughout the season, including trip limits, trap limits, and days out of the fishery. Additionally, the amendment modifies the fishing mortality reference points to include a threshold level, includes a more timely and comprehensive reporting system, and allows for the initiation of a limited entry program to be pursued through the adaptive management process. Addendum I to Amendment 2, approved in November 2012, clarifies the annual specification process, introduces a research set aside provision, and allocates the TAC with 87% for the trawl fishery and 13% for the trap fishery based on historical landings by each gear type.
While northern shrimp have historically provided a small but valuable fishery to the New England states, poor stock condition, largely driven by environmental factors, led the Northern Shrimp Section to institute a fishery moratorium for the 2014, 2015, and 2016 fishing seasons; the first time in over 30 years the fishery was closed.
In 2014, the Section initiated Amendment 3 to develop a limited entry program to be implemented as the resource recovers. Public comment on the Public Information Document for Draft Amendment 3 was sought throughout the winter and early spring of 2015. The Section reviewed public comment in June and directed the Plan Development Team (PDT) to develop a limited entry program for Draft Amendment 3. However, at their September meeting, the Section decided to postpone the development of Amendment 3 until Maine can address over-capacity in its fishery.