Modeling small-pelagic fish biomass in the Indonesian seas: climate variability and climate change impacts

Abstract

The present study uses the Community Earth System Model, version 1– Biogeochemistry [CESM1(BGC)] to examine the influence of climate variability and climate change on small pelagic fish biomass in the Indonesian seas. The fish biomass was calculated based on a fish production model according to primary production and energy transfer at the tropic level. The primary production data were obtained from results of CESM1(BGC) model from 1850 to 2015. Empirical orthogonal function (EOF) analysis of the calculated fish biomass identifies three regions in the Indonesian seas that are associated with coastal upwelling. These regions are located in (1) southern coast of Central Java Province until west-coast of West Sumatra Province, (2) southern coast of Central Java Province until the southern coast of Bali Province, and (3) Banda-Arafura Seas. Fish production variability in these regions exhibits semi-annual, annual, and IOD-ENSO related signals. Climate change impact for RCP 4.5 scenario produces ‘fish stock increase status’ in 2025 for the three regions, while the ‘fish stock current status’ will reoccur in 2050, except for the western part of Sumatra (part of region-1) which alters to ‘fish stock decrease status’.