# Environmental Responses and Interspecific Associations of Fish Communities in the Zhoushan Fishing Ground Revealed by HMSC

## TL;DR

This study examines how fish communities in China's Zhoushan Fishing Ground are changing due to environmental factors and human activities, offering insights for sustainable management.

## Contribution

A novel two-part hurdle model within the HMSC framework is used to analyze fish community dynamics and their environmental responses.

## Key findings

- Fish distribution patterns are primarily shaped by spatial differences and long-term trends.
- Species occurrence and positive biomass responses are influenced by different ecological processes.
- Environmental variables like depth and salinity have varying impacts on different fish species.

## Abstract

The Zhoushan Fishing Ground is the largest fishing ground in China, and its fish community structure is currently undergoing change under the influence of multiple factors. To gain a deeper understanding of the fish community in this region, we built models based on 11 consecutive years of data from 2014 to 2024 for analysis. The results showed that fish distribution patterns were mainly associated with spatial differences among areas and long-term trends. In addition, the focal fish species examined in this study could be broadly divided into two groups, with one species showing associations with both groups. Meanwhile, we found that the drivers of species occurrence and those influencing positive biomass were not identical. These findings not only deepen our understanding of fish communities in the Zhoushan Fishing Ground, but also provide reference information for the conservation and management of fisheries resources, thereby helping to promote their sustainable use.

The fish community structure of the Zhoushan Fishing Ground is undergoing change due to overfishing, climate variability, and other anthropogenic stressors. To investigate community-level environmental responses and interspecific associations in this region, we used 11 consecutive years (2014–2024) of spring bottom trawl survey data from the Zhoushan Fishing Ground and integrated environmental covariates to build a two-part hurdle model within the Hierarchical Modelling of Species Communities (HMSC) framework. The results showed that the spatial random effect had the highest contribution (41%), followed by the interannual trend (18%), indicating that community occurrence patterns are primarily shaped by the superposition of stable spatial structuring and long-term change. Depth was significant for more species, whereas salinity was significant for the fewest. Residual correlations further revealed that the focal fish species could be partitioned into two assemblages with one linking species. Meanwhile, within the two-part hurdle model, the direction and significance of responses to the same covariate were not always consistent, supporting that species occurrence probability and positive biomass are governed by different ecological processes. Overall, this study provides a transferable quantitative framework for community assessment in coastal fishing grounds and offers a more operational chain of evidence for ecosystem-based fisheries management.