Skip to main content
Dryad logo

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

Citation

Gao, Jin; Thorson, James; Szuwalski, Cody; Wang, Hui-Yu (2019), Historical dynamics of the demersal fish community in the East and South China Seas, Dryad, Dataset, https://doi.org/10.5061/dryad.kkwh70s1g

Abstract

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.

Methods

We digitized historical Taiwanese otter trawler catch-and-effort (CPUE) data in the East China Sea (Lat: 17-34.5°N, Long: 108-128.5°E), which were available from the Annual Report of Effort and Catch Statistics by Area on Taiwan Demersal Fish Fisheries published by the Fisheries Agency, Council of Agriculture, Executive Yuan, Taiwan (compiled by Dr. Shean-Ya Yeh, the Demersal Fish Research Center, Institute of Oceanography, National Taiwan University) (Fig.1a). The dataset contains:

  1. total catch weight (unit = no. cases; 1 case = 30 kg approximately) for each species in four fishing seasons each year (winter: Jan-March; spring: April-June; summer: July-Sept; fall:  Oct-Dec) and year in each of 50 grid cells (dimension 0.5° latitude by 0.5° longitude); and
  2. total fishing effort (no. hauls) in each cell in each season and year for boats of 100-200 metric tons (the primary size class participating in the fishery).

Data were originally derived from logbook entries and recorded by grid.