Data from: Group foraging increases foraging efficiency in a piscivorous diver, the African penguin

Marine piscivores have evolved a variety of morphological and behavioural adaptations, including group foraging, to optimize foraging efficiency when targeting shoaling fish. For penguins that are known to associate at sea and feed on these prey resources, there is nonetheless a lack of empirical evidence to support improved foraging efficiency when foraging with conspecifics. We examined the hunting strategies and foraging performance of breeding African penguins equipped with animal-borne video recorders. Individuals pursued both solitary as well as schooling pelagic fish, and demonstrated independent as well as group foraging behaviour. The most profitable foraging involved herding of fish schools upwards during the ascent phase of a dive where most catches constituted depolarized fish. Catch-per-unit-effort was significantly improved when targeting fish schools as opposed to single fish, especially when foraging in groups. In contrast to more generalist penguin species, African penguins appear to have evolved specialist hunting strategies closely linked to their primary reliance on schooling pelagic fish. The specialist nature of the observed hunting strategies further limits the survival potential of this species if Allee effects reduce group size-related foraging efficiency. This is likely to be exacerbated by diminishing fish stocks due to resource competition and environmental change.海洋食鱼动物（marine piscivores）已演化出包括群体觅食在内的多种形态与行为适应性，旨在于捕食集群鱼类时优化觅食效率。尽管已知企鹅会在海洋中集群活动并以此类猎物为食，但目前仍缺乏实证证据支持其与同种个体结伴觅食可提升觅食效率。 本研究对搭载了动物搭载式视频记录仪（animal-borne video recorders）的繁殖期非洲企鹅的捕猎策略与觅食表现展开了考察。受试企鹅既会捕猎单独活动的鱼类，也会捕食集群远洋鱼类，同时展现出单独觅食与群体觅食两类行为模式。 收益最高的觅食场景为：在潜水上升阶段将鱼群向上驱赶，此时多数捕获对象均为去极化鱼类（depolarized fish）。相较于单独捕食单个猎物，以鱼群为目标时的单位努力捕获量（catch-per-unit-effort）显著提升，且该优势在群体觅食时更为突出。 与食性更泛化的企鹅物种不同，非洲企鹅似乎已演化出与对集群远洋鱼类的主要依赖高度绑定的特化捕猎策略。若阿利效应（Allee effects）削弱了与群体规模相关的觅食效率，那么本次观测到的特化捕猎策略特质将进一步限制该物种的生存潜力。而因资源竞争与环境变化导致的鱼类资源量缩减，可能会进一步加剧这一危机。