时空和环境因子对海州湾方氏云鳚资源丰度分布的影响

Effects of spatiotemporal and environmental factors on the distribution and abundance of Pholis fangi in Haizhou Bay using a generalized additive model

根据2011年3月、5月、7月、9月和12月在海州湾及邻近海域进行的渔业资源底拖网调查数据,研究了该海域方氏云鳚（Pholis fang）资源丰度的分布特征,并用广义可加模型（GAM）分析了其资源丰度分布与时空和环境因子之间的关系。结果表明,海州湾及邻近海域方氏云鳚资源丰度呈现明显的时空变化。方氏云鳚资源丰度7月最高,9月最低；其主要分布在海州湾东北部海域,这与受到南黄海西侧冷中心的影响有关。GAM 分析表明,月份、水深和离岸距离对方氏云鳚的资源丰度具有显著影响。方氏云鳚的资源丰度随水深的增加而增大,随离岸距离的增大呈现先增加后降低的趋势。在离岸距离70 km 左右,水深14～36 m 时,方氏云鳚的资源丰度较大,这可能与其产卵洄游和环境因子的时空差异有关。

Haizhou Bay is an important spawning, nursery, and feeding ground for many commercially important fish-ery species. In recent years, many commercial fish populations have declined in abundance because of overfishing, cli-mate change, environmental pollution, and multiple other factors. Pholis fangi plays an important role in the food web of the Haizhou Bay ecosystem. Thus, management of a sustainable fishery in Haizhou Bay requires an understanding of the spatio-temporal distribution and abundance of Pholis fangi and their relationship with relevant environmental fac-tors. To determine spatio-temporal variation in the distribution and abundance of Pholis fangi, bottom trawl surveys were conducted in March, May, July, September, and December 2011 in Haizhou Bay. The relationships between pat-terns of distribution and environmental factors were analyzed using generalized additive models （GAM）. Abundance of Pholis fangi exhibited distinct seasonal and spatial variation, with abundance highest in July and lowest in September. Pholis fangi was primarily distributed in the northeastern part of Haizhou Bay, which is the cold center of the south-western Yellow Sea, suggesting a strong influence of the Yellow Sea Cold Water Mass on distribution patterns. GAM analysis also showed that month, depth, and distance from shore significantly influenced the distribution, where abun-dance increased with depth and distance from shore. The abundance of Pholis fangi was highest in the waters 14–36 m deep and roughly 70 km from the coast, which may relate to the reproductive migration of Pholis fangi as well as sea-sonal environmental variation.