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).
The results of the 2013 Assessment Report for Gulf of Maine Northern Shrimp indicate the northern shrimp stock is overfished and overfishing is occurring. Northern shrimp abundance in the western Gulf of Maine has declined steadily since 2006. Current biomass (1.1 million pounds) is the lowest value in recent history, estimated at 5.2% for the biomass reference period (1985-1994), and well below the biomass threshold of 19.85 million pounds and the biomass limit of 13.23 million pounds. Additionally, there has been recruitment failure for the past three years. The Northern Shrimp Technical Committee considers the stock to have collapsed with little prospect of recovery in the near future.
In the Gulf of Maine, increasing water temperatures and a decline in phytoplankton abundance (a food source for shrimp) are factors which likely have and will continue to contribute to the poor recruitment in the stock. 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.
The benchmark stock assessment was peer reviewed through the Northeast Regional Stock Assessment Review Committee on January 27-31, 2014. The assessment uses a new model which incorporates additional data sets that are not included in the stock assessment update. The Section will review the findings and consider the report for management use at its next meeting.
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 Gulf of Maine fishery for northern shrimp is managed by the Commission’s Northern Shrimp Section through an interstate agreement between the states of Maine, New Hampshire and Massachusetts.Amendment 1, implemented in 2004, 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 the 2009/2010 and 2010/2011 fishing seasons 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). In response to these issues, Amendment 2, approved in October 2011, provides management options to slow catch rates throughout the season, including trip limits, trap limits, and days out of the fishery. The Amendment completely replaces the FMP. It 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 addendum process.
Addendum I to Amendment 2, approved in November 2012, clarifies the annual specification process, and allocates the TAC with 87% for the trawl fishery and 13% for the trap fishery based on historical landings by each gear type.
In December 2013 in response to the findings of the 2013 Assessment Report, the Northern Shrimp Section established a moratorium for the 2014 fishing season to protect the remaining spawning population and reduce pressure on the collapsed stock. The Section noted that due recruitment failure, it is possible that the moratorium could extend beyond one year.