Seasonal changes in the fish assemblage in a mixed vegetation area of seagrass and macroalgae in the central Seto [Japan] Inland Sea

Kamimura, Y.; Shoji, J.

Seasonal changes in the fish assemblage in a mixed vegetation area of seagrass and macroalgae in the central Seto [Japan] Inland Sea

2009

Kamimura, Y.(Hiroshima Univ., Takehara (Japan)) | Shoji, J.

A total of 3,363 fishes belonging to more than 42 taxa in 26 families were caught during a monthly seine survey (August 2006 to July 2007) in a mixed vegetation area of seagrass (Zostera marina) and macroalgae (mainly Sargassum spp.) in the central Seto Inland Sea, Japan. The numerically dominant species were Sebastes cheni (45.0% in number), Favonigobius gymnauchen (16.9%), Hypodytes rubripinnis (16.2%), Takifugu niphobles (4.5%), Rudarius ercodes (3.7%) and Sillago japonica (3.4%) and the weight-based dominant species (% in weight) were H. rubripinnis (42.4%), S. cheni (22.6%), Thamnaconus modestus (6.7%), F. gymnauchen (4.9%), T. niphobles (4.3%) and Hexagrammos agrammus (3.5%). Mean number of fish species ranged between 3.3 (February) and 11.5 (June) /100 square m, abundance (number of fish) between 7.8 (February) and 196.5 (April)/100 square m, and biomass (wet weight) between 19.0 (February) and 441.0 (June) g/100 square m. Based on the growing season for larvae and juveniles, the dominant fish species were categorized into three types; type-I: grow in spring (macroalgae-dependent: S. cheni), type -II: grow in summer (F. gymnauchen, T. niphobles and S. japonica) and type-III: common throughout the year but the larvae and juveniles do not grow in the seagrass/macroalgae area (vegetation-independent: H. rubripinnis). Fish abundance and number of fish species increased from late winter to early spring, the season before seagrass grow but macroalgae were still abundant in addition to early summer.

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