Improving the size selectivity of crayfish fyke-net codend, applying the hexagonal mesh and sorting grid

IF 1.8 4区环境科学与生态学 Q2 FISHERIES

Marine and Freshwater Research Pub Date : 2024-04-15 DOI:10.1071/mf23224

Mehmet Cilbiz, Celalettin Aydın

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引用次数: 0

Abstract

Context Owing to the use of fyke-nets with poor size selectivity in crayfish fishery, 40.7% of the landed undersized catch is discarded as bycatch. Aims This study investigated the effects of using hexagonal mesh (Hex34) instead of diamond nets (Com34) in the traditional crayfish fyke-net and the application of a sorting-grid (SG20, SG25, SG30) and stiff-rigged net (SRN34, SRN42, SRN50) on size selectivity. Methods A covered codend technique was used for determining the size selectivity of codends. Key results The average length at 50% retention probability (L50, in total length) for the trial groups of Com34, Hex34, SG20, SG25, SG30, SRN34, SRN42 and SRN50 was estimated as 9.1, 9.5, 10.1, 11.0, 12.3, 10.0, 10.3 and 11.1 cm respectively. Additionally, the discard rates were computed in the same order as 37.0, 27.3, 14.9, 5.8, 1.9, 19.1, 9.4 and 7.7%. Conclusions In conclusion, commercial crayfish (Com34) fyke-nets have a significantly high discard rate. In the modifications tested, the discard rate has been reduced to as low as 1.9%. When taking into account both L50 and fishing efficiency indicators, SRN42 was determined as the most successful trial group. Implications The application of the study results will make a significant contribution to the sustainability of natural crayfish stocks of Türkiye.

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应用六角网和分选网格提高小龙虾耙网的大小选择性

背景由于在小龙虾渔业中使用尺寸选择性差的耙网，上岸的尺寸不足的渔获物有 40.7% 作为副渔获物被丢弃。本研究调查了在传统的小龙虾刺网中使用六角网（Hex34）而非菱形网（Com34）以及应用分选网（SG20、SG25、SG30）和硬桁网（SRN34、SRN42、SRN50）对尺寸选择性的影响。方法采用有盖鳕网技术确定鳕网的大小选择性。主要结果 Com34、Hex34、SG20、SG25、SG30、SRN34、SRN42 和 SRN50 试验组 50%保留概率时的平均长度（L50，总长度）分别估计为 9.1、9.5、10.1、11.0、12.3、10.0、10.3 和 11.1 厘米。此外，计算得出的丢弃率依次为 37.0%、27.3%、14.9%、5.8%、1.9%、19.1%、9.4% 和 7.7%。结论总之，商业小龙虾（Com34）叉网的丢弃率很高。在测试的修改中，丢弃率已降低到 1.9%。考虑到 L50 和捕捞效率指标，SRN42 被确定为最成功的试验组。意义研究结果的应用将对土耳其天然小龙虾种群的可持续性做出重大贡献。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Marine and Freshwater Research 环境科学-海洋学

CiteScore

4.60

自引率

5.60%

发文量

审稿时长

3.8 months

期刊介绍： Marine and Freshwater Research is an international and interdisciplinary journal publishing contributions on all aquatic environments. The journal’s content addresses broad conceptual questions and investigations about the ecology and management of aquatic environments. Environments range from groundwaters, wetlands and streams to estuaries, rocky shores, reefs and the open ocean. Subject areas include, but are not limited to: aquatic ecosystem processes, such as nutrient cycling; biology; ecology; biogeochemistry; biogeography and phylogeography; hydrology; limnology; oceanography; toxicology; conservation and management; and ecosystem services. Contributions that are interdisciplinary and of wide interest and consider the social-ecological and institutional issues associated with managing marine and freshwater ecosystems are welcomed. Marine and Freshwater Research is a valuable resource for researchers in industry and academia, resource managers, environmental consultants, students and amateurs who are interested in any aspect of the aquatic sciences. Marine and Freshwater Research is published with the endorsement of the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the Australian Academy of Science.