Increasing or decreasing? - Current status of the Japanese eel stock
Increasing or decreasing? - Current status of the Japanese eel stock
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DOI：
10.1016/j.fishres.2019.105348
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发表时间：
2019-12-01
影响因子：
2.4
通讯作者：
Yokouchi, Kazuki
中科院分区：
文献类型：
--
作者：
Kaifu, Kenzo;Yokouchi, Kazuki
虽然日本鳗鲡在国际自然保护联盟濒危物种红色名录中被列为濒危物种，但以前对日本鳗鲡的种群评估估计，自1990年以来，该物种的1岁以上种群一直在恢复。为了帮助了解野生日本鳗鱼的种群动态，对日本沿海和河口地区的鳗鱼渔业进行了调查，因为内陆渔业合作协会进行了鳗鱼放养，据推测这会使日本内陆沃茨的渔业数据产生偏差。我们进行了一项问卷调查，1509渔业合作协会在沿海和河口地区的日本，鳗鱼放养的可能偏差预计将相对较低。根据调查问卷，从6个渔业合作协会获得了2003 - 2018年可利用鳗鱼（黄鳗和银鳗）渔获量和努力量数据。每个渔业合作协会的单位努力量（CPUE）的标准化渔获量开发使用广义线性模型。结果表明，标准化可利用鳗鱼CPUE显着较低的六个协会中的四个。此外，在确认捕捞鳗鱼的227个渔业合作组织中，回答鳗鱼资源“相对增加”、”稳定”、“相对减少”和“减少”的分别占1.3%、5.3%、21.6%和71.8%。没有协会说鳗鱼的数量“在增加”。“此外，日本9个县报告的玻璃鳗鱼CPUE在1977-2018年和2003-2018年期间均显着降低。由于本研究中使用的数据集可能是目前最好的数据集之一，野生日本鳗鱼的股票似乎是目前在日本沿海和河口沃茨，在那里的鳗鱼股票动态的偏见是相对较低的下降。
Although Japanese eel, Anguilla japonica, is listed as endangered on the International Union for Conservation of Nature Red List of Threatened Species, a previous stock assessment of the Japanese eel estimated that the age 1 + stock of the species has been recovering since 1990. To help understand the population dynamics of wild Japanese eels, eel fisheries in coastal and estuarine areas in Japan were investigated, because inland fisheries cooperative associations have conducted eel stocking that is presumed to bias the fisheries data in inland waters of Japan. We conducted a questionnaire survey of 1509 fisheries cooperative associations in coastal and estuarine areas of Japan, where the possible bias of eel stocking is expected to be relatively low. Based on the questionnaire, exploitable eel (yellow and silver eels) catch and effort data from 2003 to 2018 were obtained from six fisheries cooperative associations. A standardized catch per unit effort (CPUE) was developed using a generalized linear model for each fisheries cooperative association. The results indicated that the standardized exploitable eel CPUE was significantly lower in four of the six associations. As for the other two associations, significant relationships between CPUE and year was not found. Additionally, of the 227 fisheries cooperative associations that confirmed they catch eels, 1.3%, 5.3%, 21.6%, and 71.8% answered that the eel stock is "relatively increasing," "stable" "relatively decreasing," or "decreasing," respectively, with no association stating that the eel stock is "increasing." Moreover, reported glass eel CPUE in nine prefectures in Japan was significantly lower in both periods of 1977-2018 and 2003-2018. Because the dataset used in this study is likely to be one of the best currently available, the wild Japanese eel stock appears to be currently declining in Japanese coastal and estuarine waters, where the bias of eel stocked eels on stock dynamics is thought to be relatively low.