Mizuhopecten yessoensis


Yesso scallop, Zhangzidao scallop, Japanese scallop

The Yesso scallop (Patinopecten or Mizuhopecten yessoensis), has a wide distribution on the cold coasts of northern Japanese islands, in the northern part of the Korean Peninsula, Russian Primorye, Sakhalin, and Kuril Islands.

The coastline of the Sea of Okhotsk, Hokkaido, is ideal habitat for the scallop Patinopecten yessoensis, and has supported important fisheries for this species since the early 1900s. Maximum annual production was 80,000 tonnes in 1934, although catch records dating back to 1920 show that there were 6–13-year cycles of good and poor harvests up to 1945. Over-fishing did occur prior to 1945, although the resource normally recovered due to recruitment of a strong year class. However, rampant harvesting in the postwar decade (1945–1955) reduced annual production to ∼6000 tonnes, where it remained for the next 25 years. Efforts to restrict harvest areas and seasons, prohibit certain types of gear, and introduce size limits during this period did not succeed in restoring the fishery (Uki 2006).

A distinct genetic stock around Hokkaido is considered to exist (Sato et al. 2005).

Following the development of the technology, it became possible to culture scallop en masse in Mutsu Bay, Funka Bay, Sarufutsu and the Saroma Lake area using inexpensive and plentiful juveniles. The increases in production of scallops in hanging culture were astounding.

Still, there are several concerns for the sustainability of the scallop aquaculture, including inbreeding among the individuals derived from artificial seeds and genetic impact of stocked hatchery scallops on the natural populations. Several recent studies have begun to address these questions including genetic analysis of Japanese scallops using isozyme markers, mitochondrial DNA and a limited number of microsatellite markers (Liu et al. 2010).

There have been several studies carried out on genetic structure and diversity. Chang et al (2007) studied the genetic diversity of five cultured and natural populations of Japanese scallops using microsatellites DNA markers. The five populations were from the enhanced fishery at Zhangzi island, the natural population in north sea area of the Yellow Sea, a Japanese cultured population, a Russian population and an albino population collected from Dachangshan island. It was found that the difference in genetic diversity among the five populations was not significant. Han et al 2011 studied the genetic diversity in two-generations of cultured Japanese scallops from Dahao Island (China) and Talian Island (China) and one wild Japanese scallop population. The phenotype characters (shell length and shell height) of four F1 progeny populations were measured. Non-significant differences were found between different characters in four F1 progeny populations at different growth stages. The difference in genetic diversity among the four F1 progeny populations was not significant (Andrews et al. 2013, Akroyd et al. 2014).




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