The Gulf of Maine Northern Shrimp (Pandalus borealis) Fishery: A Review of the Record

Abstract

The Gulf of Maine fishery for northern shrimp (Pandalus borealis) has been a dynamic one, with landings varying greatly in response to resource and market conditions. A directed winter fishery developed in coastal waters in the late-1930s, which expanded to an offshore year round fishery in the late-1960s when annual landings peaked at about 13 000 tons in 1969. Landings subsequently declined to very low levels during the mid-1970s as recruitment failed and the stock collapsed, precipitating closure of the fishery in 1977. The resource recovered under restrictive management and was relatively stable at low to moderate levels of exploitation into the 1990s, with several strong year-classes recruiting to the fishery. In the mid-1990s, landings and fishing mortality increased sharply and abundance and recruitment have again declined. Environmental conditions have played an important role in affecting survival and abundance. Stock assessments have consistently shown that poor recruitment is more likely at low levels of spawning stock biomass owing to reduced total egg production. At a stock biomass level of 15 00020 000 tons, sustainable yields for the Gulf of Maine northern shrimp fishery appear to be 3 0004 000 tons per year under average environmental conditions.

Is size at sex transition an indicator of growth or abundance in pandalid shrimp?

“…Clarke et al, 2000); increased temperatures result in an obligatory increase in growth rate, smaller L t , decreased fecundity and, several years later, a decrease in population size. Other explanations for the negative relationships between temperature and shrimp abundance are numerous (Clarke et al, 2000) and include the possible influence of temperature on fecundity. Apollonio et al (1986) speculated that temperature influences fecundity via water stratification and the different temperatures encountered by maturing females during vertical migrations.…”

Distribution and reproductive aspects of the pandalid shrimp,Pandalus eous,in the deep sea of the East Sea, Korea

“…In addition, the increased GSI by depth provides the evidence that ovigerous females of shallow water species mainly distribute in shallowest depth range for hatching, and sexual maturity is achieved in deeper depth range. In case of P. eous, it has been reported that the fishery has been seasonal in nature, peaking in lateÁwinter when ovigerous females move into inshore waters and terminating in spring under regulatory closure (Clark et al 2000). In the deep water lobster, Polycheles typhlops, the highest proportion of ovigerous females was recorded for the shallowest levels of the bathmetric distribution range of the species and this suggests reproductive migrations related to egg laying and or spawning (Abello and Cartes 1992).…”

Climate change and northern shrimp recruitment variability in the Gulf of Maine

“…Relatively high northern shrimp recruitment variability was also seen during a period of high abundance and high fishing mortality from 1969 to 1974 (Fig. 3B); this was followed by a population collapse and closure of the fishery in 1977 (Clark et al 2000). In the Gulf of Alaska, shrimp recruitment variability increased prior to a major ecosystem reorganization, with 2 record YC produced shortly before a severe and persistent decline in abundance of pandalid shrimps (Anderson & Piatt 1999).…”

“…Northern shrimp are protandrous hermaphrodites, maturing as males at age 2 in the GOM, transforming to females at age 3 and reproducing as females at ages 4 and 5, after which they die (Shumway et al 1985, Clark et al 2000. Females brood embryos externally and move to shallow (< 50 m) coastal waters to release their larvae during winter.…”