TY - JOUR AU - Sedova, L. G. AU - Sokolenko, D. A. PY - 2023/03/14 Y2 - 2024/03/28 TI - Features of spatial distribution of Crenomytilus grayanus and Modiolus kurilensis (Bivalvia, Mytilidae) in Peter the Great Bay (the Sea of Japan) JF - Marine Biological Journal JA - mbj VL - 8 IS - 1 SE - Scientific communications DO - 10.21072/mbj.2023.08.1.07 UR - https://marine-biology.ru/mbj/article/view/373 SP - 76-92 AB - <p>The bivalves of the family Mytilidae – <em>Crenomytilus grayanus</em> (Dunker, 1853) and <em>Modiolus kurilensis</em> Bernard, 1983 – are Pacific, Asian species and mass representatives of upper sublittoral epifauna in coastal waters of Peter the Great Bay (the Sea of Japan). <em>C. grayanus</em> is a traditional commercial species, and <em>M. kurilensis</em> is a promising one; resources of both molluscs are significant. The aim of the work is the comparative analysis of spatial distribution and biomass of <em>C. grayanus</em> and <em>M. kurilensis</em> on different types of bottom sediments and habitat depths in Peter the Great Bay. The investigation was carried out in 2007–2019 by scuba diving hydrobiological techniques at depths of down to 20 m. The data were analyzed for 5,911 stations; Mytilidae representatives were found at 1,635 stations. For mytilids, vital mass of each individual was determined, and mean biomass was estimated. The landscape diversity of Peter the Great Bay bottom determines an almost ubiquitous distribution of <em>C. grayanus</em> and <em>M. kurilensis</em>, and this reflects good adaptation of molluscs to conditions typical for this part of their area. Monospecific aggregations of <em>C. grayanus</em> prevailed both on hard and soft bottom sediments (78.6 and 38.2% of total stations with Mytilidae, respectively), while mixed aggregations of both species prevailed on soft bottom sediments (38.3%). On soft bottom sediments, monospecific aggregations of <em>M. kurilensis</em> were more common (23.5%) than on hard ones (8.1%). In Peter the Great Bay, mean biomass of <em>C. grayanus</em> on hard bottom sediments was (728 ± 47) g·m<sup>−2</sup> varying from 524 g·m<sup>−2</sup> (the Amur Bay) to 922 g·m<sup>−2</sup> (eastern Peter the Great Bay). The value for mean biomass of <em>C. grayanus</em> on soft bottom sediments was (491 ± 51) g·m<sup>−2</sup> varying from 228 g·m<sup>−2</sup> (the Ussuri Bay) to 829 g·m<sup>−2</sup> (the Amur Bay), except for southwestern Peter the Great Bay and Boisman Bay, where the value was below 50 g·m<sup>−2</sup>. Mean biomass of <em>M. kurilensis</em> on hard bottom sediments was (370 ± 74) g·m<sup>−2</sup> varying from 18 g·m<sup>−2</sup> (Baklan Bay) to 656 g·m<sup>−2</sup> (the Empress Eugénie Archipelago water areas). The value for mean biomass of <em>M. kurilensis</em> on soft bottom sediments was (335 ± 37) g·m<sup>−2</sup> varying from 77 g·m<sup>−2</sup> (southwestern Peter the Great Bay) to 456 g·m<sup>−2</sup> (the Amur Bay), except for Boisman and Baklan bays where the species was rare. In Peter the Great Bay, maximum values of the mean biomass for both species were recorded at depths of 1–10 m (<em>C. grayanus</em>, 664–805 g·m<sup>−2</sup>; <em>M. kurilensis</em>, 347–485 g·m<sup>−2</sup>); with increasing habitat depth, the abundance of both species decreased. The mean biomass of <em>C. grayanus</em> inhabiting hard bottom sediments at 10–20 m was quite high as well – 431–507 g·m<sup>−2</sup>. On soft bottom sediments, with a shift in depth from 10–15 to 15–20 m, its mean biomass decreased from (204 ± 33) to (27 ± 11) g·m<sup>−2</sup>. The mean biomass of <em>M. kurilensis</em> inhabiting both types of bottom sediments at 10–15 m was 121–194 g·m<sup>−2</sup>, and at 15–20 m, the value was 11–60 g·m<sup>−2</sup>.</p> ER -