- Division of Marine Fisheries
Description
Longfin squid is a schooling species of the molluscan family Loliginidae. Longfin squid have an internal shell called a “pen.” Their fins are long, at least half the length of the mantle (large part of the squid in front of the head), and their head has large eyes that are covered by a cornea. They are typically pink or orange and mottled with brown or purple. They are likely color blind, but are able to use special pigment cells in their skin (called chromatophores) to change their color and patterns to escape predators or disguise themselves from prey. Longfin squid are important forage for many pelagic and demersal fish species of the Northeast US, as well as marine mammals and birds. Marine mammal predators include longfin pilot whales and common dolphins. Fish predators include striped bass, bluefish, black sea bass, mackerel, cod, haddock, pollock, hake, sea raven, dogfish, goosefish, and flounders.
Distribution and Habitat
Longfin squid are distributed in the continental shelf and slope waters from Newfoundland to the Gulf of Venezuela. The range of commercial exploitation occurs from Southern Georges Bank to Cape Hatteras, North Carolina. The Northwest Atlantic population is managed as a single stock based on the results of genetics studies conducted on squid samples collected between Cape Cod Bay and the Gulf of Mexico.
Juvenile squid shift from inhabiting surface waters to a demersal lifestyle before reaching a 2” mantle length. Off of Martha’s Vineyard, the juvenile life stage lasts about one month. Sub-adults migrate by November to the outer shelf areas where they remain until March, and are thought to overwinter in deeper waters along the edge of the continental shelf. Longfin squid are generally found at water temperatures of at least 9⁰C (48⁰F). In the waters off Massachusetts, larger individuals migrate inshore first in April-May while smaller individuals move inshore in the summer.
Life History
Longfin squid begin their lives as eggs, encased in a larger gelatinous capsule. Each female can lay 20-30 capsules, which are deposited on the ocean floor in clusters often referred to as “mops”. Developmental time in Nantucket Sound varies from 12 to 34 days in water temps from 14-20⁰C (57-68⁰F). Growth rates of juveniles and sub-adults are relatively fast with growth rates dependent on temperatures. The length at sexual maturity was found to be in the range of 8-12cm (3.2-4.7”) mantle length, but also in the 16-20cm (6.3-7.9”) range, depending on season and location. Using statoliths for age, it is evident that the longfin squid experiences exponential growth and a life span that can be less than 9 months, reducing previous maximum age estimations. Longfin squid can reach sizes greater than 40-50cm (15.8-19.7”) mantle length, although most are less than 30cm (11.8”).
Management
Longfin squid is managed primarily by the Mid-Atlantic Fishery Management Council, and more locally, the Division of Marine Fisheries. Fishermen with a limited access permit can fish for unlimited amounts of longfin squid while the fishery is open. All other fishers must obtain an incidental catch permit and abide by possession limits. An annual coast-wide catch quota is divided into trimester allocations. Managers monitor annual quotas closely, as there can be large fluctuations in abundance from year to year. Longfin squid are targeted commercially with numerous gear types, including small-mesh otter trawls, mid-water otter trawls, fish weirs, and rod and reel.
During the most recent assessment (2016) the longfin squid stock was determined to be not overfished based on biomass estimates derived from the Northeast Fisheries Science Center (NEFSC) spring and Northeast Area Monitoring and Assessment Program (NEAMAP) fall trawl surveys. The estimated biomass was nearly 3.5 times greater than the pre-determined biomass of a sustainably harvested resource. The overfishing status could not be determined because there are no fishing mortality reference points for the stock. Longfin squid are a short-lived species that mature in approximately 150 days and exhibit spawning cohorts throughout the year. These findings strongly support the hypothesis that the inshore fishery is entirely dependent upon squid which survive the winter offshore fishery season.
By Julia Kaplan, Communications Specialist
