Stomach content, biomass, abundance and body score of long-tailed ducks (Clangula hyemalis) from south-eastern Baltic Sea

The long-tailed duck (Clangula hyemalis) is a vulnerable and declining species wintering in the Baltic Sea. The introduction of the invasive fish, the round goby (Neogobius melanostomus), dramatically impacted the benthic macrofauna in hard-bottom, while no significant changes occurred in soft-bottom benthic macrofauna. Therefore, we aimed to assess the extent to which the diet of long-tailed duck changed in two different bottom types. We analysed the stomach content of 251 long-tailed ducks bycaught in gillnets from 2016 to 2020 in hard- and soft-bottom habitats and compared these results with those published by Žydelis and Ruškyte (2005). The results show that the long-tailed duck experienced a change in diet in hard-bottom habitats, shifting from the blue mussel to Hediste diversicolor, barnacles and fish. In soft-bottom habitats, their diet remained similar over time and was based on H. diversicolor, a few bivalve species and Saduria entomon. There was no evidence of significant differences in diet neither between sex nor age. Despite the above-mentioned changes in diet, the average body condition of the species did not change neither over time nor between habitats. This confirms that long-tailed ducks have high feeding flexibility and quick species response to changes in prey availability, as they are capable of shifting their diet to new prey.

搜集汇总

背景与挑战

背景概述

该数据集包含了2016年至2020年在波罗的海东南部收集的251只长尾鸭（Clangula hyemalis）的胃内容物、生物量、丰度和体况评分数据，旨在评估入侵鱼类圆斑拟隆头鱼对长尾鸭食性及身体条件的影响。分析显示，长尾鸭在硬底栖息地的食性发生显著变化，而从软底栖息地捕获的个体食性相对稳定，且体况在不同栖息地和时间上无显著差异，表明该物种具有较高的食性灵活性。