Distribution Pattern of Far Eastern Sea Cucumber Apostichopus japonicus in Busse Lagoon (Southern Sakhalin)

Abstract

We analyzed the distribution pattern and size structure in aggregations of the far eastern sea cucumber (trepang), Apostichopus japonicus in Busse Lagoon (Southern Sakhalin). Trepang populations, which differ in their size composition and population density, have been grouped by their spatial differentiation. It has been shown that in the absence of solid substrates in the lagoon, the animals gather on substrates such as the alga Ahnfeltia tobuchiensis and on clusters of the oyster Crassostrea gigas. It is found that on the southeastern part of the lagoon, trepang makes up an extensive aggregation confined to the bed of Ahnfeltia; the distribution of the holothurians mostly has a random pattern. In the northwestern part of the lagoon, trepang makes up aggregations on oyster and algal beds; the distribution of these aggregations shows a random pattern.