| 摘要: |
| 为掌握江苏全海域刀鲚资源状况,为后期长江禁捕效果评估提供支撑资料, 2017年5月、8月、11月与2018年2月在江苏海域(31°45′~35°00′N, 119°30′~125°00′E)分别进行了4次渔业资源调查, 并绘制了尾数资源密度与重量资源密度分布图, 利用SPSS 26软件对当年的刀鲚资源状况进行评估, 积累长江禁渔前刀鲚鱼种系统数据。结果表明: (1) 刀鲚除秋季(11月)与冬季(2月)存在部分群体分布于“机轮拖网渔业禁渔区线”(以下简称“禁渔区线”)外侧之外, 其余时间均在江苏近岸海域(江苏境内“禁渔区线”到海岸线之间的水域)栖息洄游, 江苏近岸海域是刀鲚主要栖息索饵水域; (2) 春季(5月)影响江苏海域刀鲚分布的环境因子较多, 主要有水温、盐度、溶氧、深度、透明度等, 这可能与刀鲚正处于产卵旺期, 对环境因子变化敏感有关; 夏季(8月)影响江苏海域刀鲚分布的环境因子是透明度, 此时刀鲚刚结束产卵不久, 返回近海后急需补充能量, 丰富的营养物质成为影响其分布的主要因素, 此时为北半球夏季, 江苏省境内60余条入海河流正值汛期, 入海河水携带大量的营养物质, 成为返海刀鲚优良的索饵场; 秋季水温降低, 刀鲚开始越冬洄游, 水温成为影响刀鲚分布的重要因素; 冬季, 随着刀鲚性腺再次发育成熟, 新一轮的生殖洄游开始, 刀鲚栖息水层上升, 水深成为影响冬季刀鲚分布的关键因素; (3) 与长江禁捕后其他研究者在长江口收集到的刀鲚规格、全长-体重拟合方程综合对比, 发现自“长江十年禁捕”逐步实施后, 刀鲚种群渔获规格逐渐增大, 全长、体重开始逐渐增长, 长江刀鲚种群呈现资源恢复趋势。 |
| 关键词: 刀鲚 江苏海域 时空分布 环境因子 禁捕效果 |
| DOI：10.11693/hyhz20231100239 |
| 分类号:Q958;S931.1;S937 |
| 基金项目:江苏省水生生物资源重大专项暨首次水生野生动物资源普查-近海海洋水生野生动物资源普查,ZYHB2016-2号;渔业生态与资源监测-长江口邻近海域渔业监测,2023-SJ-137号。 |
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| SPATIO-TEMPORAL DISTRIBUTION AND INFLUENCING FACTORS OF COILIA NASUS IN SEA AREAS OFF JIANGSU BEFORE FISHING BAN IN CHANGJIANG RIVER |
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LI Zi-Dong, TANG Jian-Hua, WU Lei, YAN Xin, GE Hui, SHI Jin-Jin, WANG Yan-Ping, ZHU Hai-Chen, WANG Chu-Qing
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Jiangsu Marine Fisheries Research Institute, Nantong 226007, China
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| Abstract: |
| To understand the resource status of Coilia nasus in the sea areas off Jiangsu, South Yellow Sea, and provide better supporting data for the evaluation of the effectiveness of the 10-year fishing ban plan in Changjiang River that started in January 1, 2020. Four seasonal fishery resource surveys were conducted in the sea area (31°45′~35°00′N, 119°30′~125°00′E) in May (spring), August (summer), November (fall) 2017, and February (winter) 2018. The distribution of stock resource density and weight resource density of the current situation of C. nasus resources was mapped using SPSS 26 software. Results show that the C. nasus populations distributed in the offshore areas of Jiangsu Province in the spring and summer or in the outside of the waters between the “line of closed fishing area for bottom trawed fishery by motorboat” and the coastline of Jiangsu Province in the fall and winter. In the spring, many environmental factors affected the distribution of C. nasus, including water temperature, salinity, dissolved oxygen, depth, and transparency because C. nasus were at the peak of spawning and were sensitive to environmental changes in spring. In the summer, the environmental constraint on the distribution of C. nasus in the study area was transparent, the species had just finished spawning and needed to replenish energy after returning to the offshore area, and thus nutrient-rich materials became the important constraint to the distribution. In the fall, water temperature decreased, and C. nasus began to migrate to the over-wintering ground, the water temperature became the main influencing factor. In the winter, the degree of sex maturity of C. nasus increased, a new round of spawning migration began, the depth of habitat layer of the species rose up, and thus the water depth became the key limiting factor. Compared in the size of C. nasus reported by other researchers after the fishing ban implementation in the Changjiang River, the species size of C. nasus showed a gradual increase trend, and the length and weight began to increase steadily, showing good outcome of resource recovery of C. nasus population in the river. |
| Key words: Coilia nasus sea areas off Jiangsu spatio-temporal distribution environmental factors the effect of fishing ban |
