Local movements and site-tenacity of minke whale in Iceland in relation to feeding and a northward distribution shift

Population dynamics, movement patterns and migratory routes of common minke whales (Balaenoptera acutorostrata) in the North Atlantic are not yet fully understood. Small-scale movements of minke whales within Skjálfandi Bay, Iceland, were analysed and discussed in relation to population dynamics in the North Atlantic. Local distribution and abundance of minke whales were investigated on both individual and population basis. Data were obtained through continuous sighting surveys from 2005 to 2018, conducted by trained volunteers using whale watching vessels as opportunistic research platforms. Variations in abundance might reflect a species distribution shift to higher latitudes. Competition for prey and the general movement of several species from different taxonomic groups support a potential range shift. For the first time, habitat use of minke whales in Skjálfandi Bay was revealed through spatial analysis, as well as small-scale site-tenacity, proven through modelling of distances between individual and random relocations. To improve the status of the declining minke whale population around Iceland we suggest recognition of separate minke whale management units using different areas. Additionally, we encourage the protection of different feeding grounds which will reduce local anthropogenic stressors and likely improve minke whales' coping with climate change and shifts in prey.

北大西洋普通小须鲸（Balaenoptera acutorostrata）的种群动态、移动模式与洄游路线尚未得到完全阐明。本研究针对冰岛斯卡加峡湾（Skjálfandi Bay）内小须鲸的小型移动行为展开分析，并结合北大西洋种群动态背景展开讨论。研究从个体与种群两个维度，对小须鲸的局部分布特征与种群丰度进行了调查。数据采集自2005年至2018年的连续目击调查，由经过专业培训的志愿者以观鲸船作为机会主义研究平台完成。种群丰度的变化或反映出该物种正向高纬度区域发生分布转移。猎物资源竞争以及不同分类类群下多个物种的整体移动趋势，均为这一潜在的分布范围偏移提供了支撑。本研究首次通过空间分析手段，揭示了斯卡加峡湾内小须鲸的栖息地利用模式；同时通过对个体定位点与随机重定位点间距离的建模分析，证实了该种群具备小型尺度的栖地忠实性。为改善冰岛周边日渐衰退的小须鲸种群现状，我们建议依据不同海域划分独立的小须鲸管理单元。此外，我们呼吁加强对各类觅食场的保护，以降低局地人为胁迫因素，进而助力小须鲸更好地应对气候变化与猎物资源变动带来的挑战。