Improving size selectivity of round pot for Charybdis japonica by configuring escape vents in the Yellow Sea, China

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Improving size selectivity of round pot for Charybdis japonica by configuring escape vents in the Yellow Sea, China https://t.co/ZZm1YztLYM @thePeerJ https://t.co/2VmgNx46TO
Aquatic Biology

Main article text

 

Introduction

Materials and Methods

Gear modification

Sea trials

Model for size selection

where NjCH is the number of individuals in the CH class caught by pots with j-sized escape vents, pjis the relative fishing intensity (defined as the probability that an individual entered the round pot with a j-sized escape vent, given that it entered the combined (test and control) gears), jpj=1, and sj(CH,v) is the retention probability with the unknown selectivity parameter vector v (Wileman et al., 1996; Yang, Tang & Liang, 2011; Tang et al., 2019).

where the two sums are for pot deployments conducted with the j-sized escape vent and CH classes, respectively.

Estimation of exploitation pattern indicators

where the summation of j is over hauls with a specific escape vent size, and ch is over CH classes. nTjch and nCjch represent the number of individuals of CH class in haul j found in the test and control pots, respectively. nP_ and nP+ indicate the retention efficiency of test pots for individuals below and above the MLS of CH. A lower value of nP_ and a higher value of nP+ indicate that the pots release more undersized individuals and retain more legal-sized individuals, which is beneficial to the sustainable development of fishery resources. nRatio indicates the ratio of undersized and legal-sized individuals retained.

Results

Discussion

Conclusion

Supplemental Information

The raw catch data overview from the sea trials.

These data were used for statistical analysis to compare the size selectivity and catch efficiency of pots with different modifications.

DOI: 10.7717/peerj.12282/supp-1

Additional Information and Declarations

Competing Interests

The authors declare that they have no competing interests.

Author Contributions

Mengjie Yu conceived and designed the experiments, performed the experiments, analyzed the data, prepared figures and/or tables, authored or reviewed drafts of the paper, and approved the final draft.

Liyou Zhang performed the experiments, prepared figures and/or tables, and approved the final draft.

Changdong Liu analyzed the data, authored or reviewed drafts of the paper, and approved the final draft.

Yanli Tang conceived and designed the experiments, authored or reviewed drafts of the paper, and approved the final draft.

Data Availability

The following information was supplied regarding data availability:

The raw catch data are available in the Supplementary File.

Funding

This work was supported by the Project of Marine and Fishery Technology Innovation of Shandong (No. 2017HYCX007). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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