2015 Assessment of the Squid Stock Complex in the Gulf of Alaska
February 21, 2015
Squids are marine molluscs in the class Cephalopoda (Group Decapodiformes). They are streamlined animals with ten appendages (2 tentacles, 8 arms) extending from the head, and lateral fins extending from the rear of the mantle. Squids are active predators which swim by jet propulsion, reaching swimming speeds up to 40 km/hr, the fastest of any aquatic invertebrate. Squids also hold the record for largest size of any invertebrate (Barnes 1987). The squid assemblage in the BSAI is better understood than in the GOA, so some of the information in this section comes from the BSAI.
In the Gulf of Alaska region there are at least 15 species of squid (Table 1). The most abundant species is Berryteuthis magister (magistrate armhook squid). Members of these 15 species come from six families in two orders and can be found from 10 m to greater than 1500 m. All but one, Rossia pacifica (North Pacific bobtail squid), are pelagic but B. magister and Gonatopsis borealis (boreopacific armhook squid) are often found in close proximity to the bottom. The vertical distribution of these three species, as well as the large size of the latter two, are the probable cause of their predominance in the GOA bottom trawl survey relative to other squid species. However no squid species appear to be well-sampled by the GOA survey. Most species are associated with the slope and basin. In the GOA trawl survey the greatest squid biomass is found between 200 m and 300 m (Figure 1), and the spatial distribution is accordingly limited mainly to the continental slope, the Shelikof Sea Valley, and the various canyons that intersect the GOA shelf (Figure 2). Since most of the data come from groundfish survey bottom trawls, the information on abundance and distribution of those species associated with the bottom is much more accurate than that of the pelagic species.