By-catch from prawn trawling in the Hawkesbury River, New South Wales: species composition, distribution and abundance [fishes; crustaceans; molluscs]
1990
Gray, C.A. | McDonall, V.C. | Reid, D.D. (New South Wales Agriculture and Fisheries, Cronulla (Australia). Fisheries Research Inst.)
In monthly sampling between March 1986 and February 1988, the total incidental catch comprised 75 species of fish, 13 species of crustaceans and 5 species of molluscs: 42 species were commercially and-or recreationally important. The species composition of the by-catch differed between the area closest to the mouth of the estuary and that furthest upstream. The number of species in the by-catch decreased with increasing distance upstream. Annual and seasonal changes in the number of species in the by-catch decreased with increasing distance upstream. Annual and seasonal changes in the number of species were similar in all areas along the river: more species were caught in 1987 than in 1986, and in autumn and winter each year. The number of individuals caught differed among areas and these differences varied between years. Seasonal fluctuations in the members of individuals caught varied between years, but these variations were similar in all areas. In the area furthest upstream there were no apparent differences in the numbers of species and individuals caught by prawn trawl sampling in sections of the river open or closed to prawn trawling.
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