Modelling the spatial distribution of three Portunidae crabs in Haizhou Bay, China.

Jing Luan,Chongliang Zhang,Ying Xue,Binduo Xu,Yiping Ren,Suzannah Rutherford

doi:10.1371/journal.pone.0207457

Jing Luan, Chongliang Zhang + Show 4 more

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https://doi.org/10.1371/journal.pone.0207457

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Abstract

Crab species are economically and ecologically important in coastal ecosystems, and their spatial distributions are pivotal for conservation and fisheries management. This study was focused on modelling the spatial distributions of three Portunidae crabs (Charybdis bimaculata, Charybdis japonica, and Portunus trituberculatus) in Haizhou Bay, China. We applied three analytical approaches (Generalized additive model (GAM), random forest (RF), and artificial neural network (ANN)) to spring and fall bottom trawl survey data (2011, 2013–2016) to develop and compare species distribution models (SDMs). Model predictability was evaluated using cross-validation based on the observed species distribution. Results showed that sea bottom temperature (SBT), sea bottom salinity (SBS), and sediment type were the most important factors affecting crab distributions. The relative importance of candidate variables was not consistent among species, season, or model. In general, we found ANNs to have less stability than both RFs and GAMs. GAMs overall yielded the least complex response curve structure. C. japonica was more pronounced in southwestern portion of Haizhou Bay, and C. bimaculata tended to stay in offshore areas. P. trituberculatus was the least region-specific and exhibited substantial annual variations in abundance. The comparison of multiple SDMs was informative to understand species responses to environmental factors and predict species distributions. This study contributes to better understanding the environmental niches of crabs and demonstrates best practices for the application of SDMs for management and conservation planning.

Highlights

Many fish populations have decreased in abundance and shifted distributions due to marine pollution, climate changes and over-exploitation [1,2,3]
The biomass data of the three crab species were collected in Haizhou Bay, China (34 ̊250 −35 ̊350N, 119 ̊250−121 ̊50E), an open bay on the south-western Yellow Sea
variation inflation factor (VIF) test suggested that sea surface temperature (SST) showed multicollinearity with other variables

Summary

Introduction

Many fish populations have decreased in abundance and shifted distributions due to marine pollution, climate changes and over-exploitation [1,2,3]. In many marine ecosystems the declines of large predatory species have coincided with increase of small size, short-lived crustacean, including shrimps and crabs [4]. The emerging economic values of crustacean species tend to be large and provide ample supports for local, small-scale fisheries [5,6]. An increase of Portunidae contributed substantially to crab fisheries in the Yellow Sea over recent decades.

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