On The Finding of a Spawning Ground of the Alaska Skate ( Bathyraja parmifera ) in the Northwestern Part of The Sea of J
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On The Finding of a Spawning Ground of the Alaska Skate (Bathyraja parmifera) in the Northwestern Part of The Sea of Japan V. V. Panchenkoa, * and D. V. Antonenkob aNational
Scientific Center for Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok, Russia Federal Research Institute of Fisheries and Oceanography, Pacific Branch—TINRO, Vladivostok, Russia *e-mail: [email protected]
bRussian
Received September 23, 2019; revised September 30, 2019; accepted September 30, 2019
Abstract—The discovery of a spawning ground for Alaska skate Bathyraja parmifera in the northwestern part of the Sea of Japan (42°21′1″ N 131°16′6″ E), at a depth of 216–224 m and a bottom temperature of 1.0°C It is reported for the first time. Spawners and egg cases were found at the spawning ground. Keywords: Alaska skate Bathyraja parmifera, male, female, spawning ground, egg case, embryo, Sea of Japan DOI: 10.1134/S0032945220050057
Skates of the suborder Rajoidei are widespread in the North Pacific Ocean. Alaska skate Bathyraja parmifera is a widely Boreal, predominantly Asian species (Dolganov, 1999; Mecklenburg et al., 2002; Parin et al., 2014). In the Russian waters of the Sea of Japan, it is a monodominant species of skates, which accounts for >90% of the biomass of the representatives of the suborder living here (Vdovin et al., 2004; Solomatov 2004; Sokolovskii et al., 2007). This communication presents for the first time the data on the spawning ground of the Alaska skate found in the northwestern part of the Sea of Japan. MATERIALS AND METHODS Our own data collected during the trawl survey served as materials for the present study. The study was performed onboard TINRO research vessel “Bukhoro” on 18.06−09.08.2007 off the mainland coast of the Sea of Japan (Fig. 1). Totally 214 trawlings using the DT/TM-27.1/24.4 m bottom trawl were carried out at depths of 12–623 m. During the study period, 278 specimens of the Alaska skate were recorded and their total length, TL measured. A sample (250 specimens) was taken from the mass collection of Alaska skate egg cases to determine the proportion of empty capsules and shells containing developing embryos. The distribution map was plotted using the Surfer software. RESULTS AND DISCUSSION In the northwestern part of the Sea of Japan, Alaska skate is recorded in a wide range of depths, from 40 to 830 m; however, only a small proportion of
individuals inhabit the shelf zone (Antonenko et al., 2007). During our study period, it occurred from 105 to 618 m: depths close to the maximal we studied. In mid-June, abeam the Gamov Peninsula, in one trawl, in addition to fish and invertebrates, a massive presence of skate egg cases was noted. The trawl was positioned on the ground in coordinates 42°21′1″ N 131°16′6″ E; lifting aboard, in 42°22′2″ N 131°17′7″ E (Fig. 1). The depth at the trawling site varied from 216 m at the beginning to 224 m at the end. During 30 minutes of trawling ~ 76000 egg cases were sampled, 10% of which contained eggs with developing e
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