Importance of fisheries discards and experience for seabird behavior and energetics

为了开发散布在大面积上的海洋资源，信天翁和海燕每天飞行数百公里，很少照顾它们的雏鸟。在人为影响很大的海洋生态系统中，由于渔船产生大量抛弃物，如加工鱼的内脏、非目标鱼种和体型过小的鱼，猎物的可获得性往往会改变。它们不仅为登船的海鸟提供了可预测的丰富食物来源，而且抛弃物还有助于获得底层鱼类这一新的食物来源。因此，在许多渔场，丢弃物是海鸟的重要食物。这可能对海鸟觅食生态学产生重要影响。本研究的目的是提高我们的理解行为适应猎物的可用性的变化，使用Scopoli的Shearwater在地中海，一个物种，自然猎物和渔业丢弃的案例研究。为了评估渔业废弃物消费的程度和影响，我们将使用GPS跟踪、加速度记录的代谢率测量和非侵入性遗传饮食测定的组合。我们将调查是否使用渔业丢弃的剪水发生在响应其天然猎物的低可用性，或者如果这个物种已经适应了定期利用这种资源，独立于其天然猎物的可用性。此外，我们将比较有经验的和新的繁殖者，以评估成年人的质量如何影响这种行为，并评估自然猎物和渔业丢弃物消耗的能量平衡。

To exploit marine resources that are scattered patchily over large areas, and often unpredictable, albatrosses and petrels cover hundreds of kilometres per day and attend their chicks infrequently. In marine ecosystems with strong anthropogenic influences, the prey availability is often altered by the presence of fisheries vessels that produce large quantities of discards such as offal from processed fish, non-target species and undersized fish. Not only do they provide a predictable and abundant source of food to seabirds attending fishing vessels, but discards also facilitate access to demersal fish as a novel food source. In many fishery areas, discards thus contribute significantly to the diet of seabirds. This can have important implications on the seabirds foraging ecology. The aim of the present study is to enhance our understanding of behavioural adaptations in response to changes in prey availability, using a case study of Scopoli's shearwater in the Mediterranean Sea, a species that takes both natural prey and fisheries discards. To evaluate the extent and implications of fisheries discard consumption, we will use a combination GPS tracking, measurements of metabolic rates from acceleration logging, and non-invasive genetic diet determination. We will investigate whether the use of fisheries discard by the shearwaters occurs in response to low availability of their natural prey or if this species has adapted to regularly exploit this resource, independently of the availability of their natural prey. Moreover we will compare experienced and novel breeders so assess how the quality of adults influences this behaviour, and evaluate the energetic balance of natural prey and fisheries discard consumption.