New data on the distribution and size composition of the North Pacific spiny dogfish &lt;i&gt;Squalus suckleyi&lt;/i&gt; (Girard, 1854)

Alexei M Orlov,Eugeny F Kulish,Vadim F Savinykh,Dmitry V Pelenev

doi:10.3989/scimar.03439.22c

Abstract

The results of long-term research on the spatial and vertical distribution of the North Pacific spiny dogfish Squalus suckleyi in the North Pacific Ocean and its size composition are presented. In total, data from 7059 catches of this species were analyzed (3178 with associated capture depth). The description of size composition is based on measurements of 413 specimens caught by driftnets, 328 by pelagic trawls and 722 by bottom trawls. This species was found to be most widely distributed in the North Pacific in the summer and autumn months during feeding migrations. Seasonal and long-term changes in the spatial distribution were observed. A wide distribution of S. suckleyi in the Bering Sea was recorded after the year 2000, which is likely associated with recent climate change. Occurrence of the species in the water column and near the bottom differed considerably. In the water column, the maximum number of captures was observed within the upper 25 m layer (about 90%). Near the bottom, this species was most abundant at depths less than 50 m (over 45%) and within a depth range of 101-200 m (about 50%). The catch of S. suckleyi during the daytime was considerably larger than in the night, possibly due to vertical diurnal migrations. This species was found at water temperatures ranging from 0 to 12.7°C, and maximum catches were observed at temperatures over 8°C. Size compositions of bottom and pelagic trawl catches were similar (mean length 69.1 and 68.6 cm respectively) while driftnet catches were composed of larger specimens (mean length 75.3 cm).

Highlights

The taxonomic status of Squalus suckleyi has undergone some changes
The North Pacific spiny dogfish S. suckleyi is endemic to the North Pacific Ocean (Ebert et al 2010) and is widely distributed as far north as the Gulf of Anadyr in the Bering Sea on the Asian coast and Kotzebue Sound in the Chukchi Sea in American waters
The aim of this paper was to document the distribution of S. suckleyi in the North Pacific Ocean, analyze seasonal and long-term population changes, compare the size composition from different fishing gears, and report the physiological condition of selected individuals

Summary

Introduction

The taxonomic status of Squalus suckleyi has undergone some changes. After the original description by Girard (1854), the name S. suckleyi remained in the scientific literature during the hundred years (Jordan and Evermann 1896, Garman 1913, Starks 1917, Walford 1935, Schultz 1936, Clemens and Wilby 1946). The taxon was considered as a junior synonym (Bigelow and Schroeder 1948, 1957, Jones and Geen 1976) or subspecies (Lindberg and Legeza 1956, 1959) of Squalus acanthias. Recently the development of new techniques involving DNA analysis has allowed researchers (Ward et al 2007, Verissimo et al 2010) to detect significant genetic differences between S. suckleyi and S. acanthias, which has prompted the resurrection of the taxon S. suckleyi (Ebert et al 2010). The North Pacific spiny dogfish S. suckleyi is endemic to the North Pacific Ocean (Ebert et al 2010) and is widely distributed as far north as the Gulf of Anadyr in the Bering Sea on the Asian coast and Kotzebue Sound in the Chukchi Sea in American waters. In the Russian waters of Primorye and Sakhalin, there was a specialized fishery for this species before World War II which harvested several tens of thousands of metric tons annually (Kaganovskaya 1937, Fadeev 1984)

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