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首页> 外文期刊>ICES Journal of Marine Science >Evaluating the effectiveness of a seasonal spawning area closure
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Evaluating the effectiveness of a seasonal spawning area closure

机译：评估季节性产卵区关闭的有效性

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Fish that aggregate at predictable locations and times to spawn are often vulnerable to over-exploitation. Seasonal closures have often been implemented in an attempt to alleviate such impacts but the effectiveness of these measures is rarely tested. This study evaluates the effectiveness of a spawning closure for Atlantic cod (Gadus morhua) in the Firth of Clyde off the Scottish West Coast (ICES Area VIa). This closure was introduced in March 2001 as an emergency measure to allow as many cod as possible to spawn and avoid the build-up of displaced effort from another spawning closure. Genetic, tagging, and otolith microchemistry investigations indicate that cod inhabiting the Clyde are reproductively isolated from other resident groups in the central and northern part of the Scottish West Coast stock. This study used a beyond-Before-After, Control-Impact approach to compare population trends of the Clyde spawning aggregation before and after the introduced area closure, using two other sub-population spawning grounds as control areas. There was no evidence of local recovery in terms of abundance, biomass, or reduced mortality in the Clyde more than a decade after establishing the closure. Mortality may have remained high because young cod are still caught as bycatch in the Nephrops fishery in the area and the predation rate may have increased due to an expanding whiting population. Considering the state of the already severely depleted Clyde sub-population when the closure was implemented the measure appears to have been too little and too late. The tendency to implement such spawning closures on nearly collapsed stocks may be why these measures often appear to have been ineffective.
机译：在可预见的地点和产卵时间聚集的鱼类通常容易遭受过度开发。经常实行季节性关闭以减轻这种影响，但是很少测试这些措施的有效性。这项研究评估了在苏格兰西海岸（ICES地区VIa）的克莱德峡湾大西洋鳕（Gadus morhua）产卵封闭的有效性。该关闭措施于2001年3月引入，是一项紧急措施，目的是使尽可能多的鳕鱼产卵，并避免由于另一产卵关闭而增加流离失所的努力。遗传，标签和耳石微化学研究表明，居住在克莱德的鳕鱼与苏格兰西海岸种群中部和北部的其他居民种群繁殖分离。这项研究使用了“前后前后控制”方法，比较了引入的区域封闭前后克莱德产卵聚集体的种群趋势，并使用其他两个子种群产卵场作为控制区域。建立封闭后十多年来，尚无证据表明克莱德地区的丰度，生物量或死亡率降低。死亡率可能仍然很高，因为该地区的海螯虾捕捞中仍将幼鳕鱼作为兼捕物捕获，捕食率可能由于白鲸种群的增加而增加。考虑到实施封闭措施时已经严重耗尽的Clyde子种群的状况，该措施似乎太少也太迟。倾向于对几乎崩溃的股票实施这种产卵关闭的趋势可能是为什么这些措施通常似乎无效的原因。

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