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 the late 1950s and soon experienced an incredible expansion in landings, peaking in 1969 at 28.3 million pounds. Over the next decade, landings dropped precipitously low and the fishery closed in 1978 due to a stock collapse. It slowly reopened in 1979 and landings increased steadily to over 11 million pounds by 1987, ranged from 5.1 to 9.7 million pounds during 1988-1994, and then rose dramatically to 20.1 million pounds in 1996. Landings subsequently declined to the lowest levels since the 1978 closure to 992,250 pounds in the 25-day 2002 season. Landings then increased steadily, jumping to 10.8 million pounds in 2007 and again to 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 scheduled to be 136 days but 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 2014-2017 fishing seasons.
The 2017 Stock Status Report for Gulf of Maine (GOM) Northern Shrimp indicates abundance and biomass indices for 2012–2017 are the lowest on record of the 34 year time series, with 2017 being the lowest observed. Recruitment since 2011 has been poor and includes the four smallest year classes on record. The recruitment index in 2017 (2016 year class) was the second lowest observed. Current harvestable biomass is mainly comprised of females from the weak 2013 year class and some small, early-maturing females from the below-average 2015 year class.
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 Gulf of Maine shrimp habitat have increased over the past decade and reached unprecedented highs within the past several years. While 2014 and 2015 temperatures were cooler, 2016 and 2017 temperatures were again high, and temperature is predicted to continue rising as a result of climate change. This suggests an increasingly inhospitable environment for northern shrimp and the need for strong conservation efforts to help restore and maintain the stock. The Northern Shrimp Technical Committee considers the stock to be in poor condition with limited prospects for the near future.
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. The original Fishery Management Plan was adopted by the Commission in 1986. Amendment 1 (2014) 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 (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 (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 implement a fishery moratorium for the 2014-2018 fishing seasons. In October 2017, the Commission approved Amendment 3 which is designed to improve management of the fishery in the event that it reopens. Specifically, the Amendment refines the FMP objectives and proves the flexibility to use the best available information to define the status of the stock and to set the total allowable catch. Furthermore, the Amendment implements a state-specific allocation program to better manage effort in the fishery; 80% to Maine, 10% to New Hampshire, 10% to Massachusetts. The amendment also strengthens catch and landings reporting requirements, implements mandatory use of size sorting grate systems to minimize harvest of small (presumably male) shrimp, incorporates accountability measures, specifies a maximum fishing season length, and formalizes fishery-dependent monitoring requirements.