Historical dynamics of the demersal fish community in the East and South China Seas

Taiwan has a long history of fishery operations and contributes
significantly to global fishery harvest. The East and South China seas are
important fishing grounds with very limited public data. More efforts are
needed to digitize and analyze historical catch rate data to illuminate
species and community changes in this region. In this study, we digitize
historical records of catch and effort from government fishery reports for
nine commercial species caught by otter trawl, reported quarterly from
1970 to 2001 from the East and South China Seas. We analyze the four
seasons and present abundance indices, distributions and among-species
correlations for nine commercially important species from 1970-1988 (a
period with high fishing effort) using a multispecies spatio-temporal
model that estimates both covariation in multispecies catch rates,
attributed to spatial habitat preferences and environmental responses, and
indices representing trends in abundance and distribution. We find
substantial spatial, temporal and spatio-temporal variation in the
distribution of fishes and season specific patterns. We conclude by
recommending collaborative work from various adjacent countries to
digitize historical records of fishing catch rates since more records
would potentially address scientific disagreements regarding trends in
abundance and distribution for commercial fishes in this region through
comparative studies.