Simpson Victor R, Fisher David N
Wildlife Veterinary Investigation Centre, Chacewater, Truro, Cornwall, TR4 8PB, UK.
Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, TR10 9FE, UK.
BMC Vet Res. 2017 Oct 12;13(1):302. doi: 10.1186/s12917-017-1214-1.
Mortality of seabirds due to anthropogenic causes, especially entrapment in fishing gear, is a matter of increasing international concern. This study aimed at characterising the gross pathology of seabirds that drowned in fishing nets and comparing it with that in other common causes of mortality.
Post-mortem examinations were performed on 103 common guillemots, 32 razorbills, 37 shags and 5 great northern divers found stranded in Cornwall during 1981-2016. Pathology in birds that died in confirmed incidents of drowning in fishing nets (n = 95) was compared with that in cases of suspected drowning (n = 6), oil (n = 53) and polyisobutylene (PIB) (n = 3) pollution, adverse weather (n = 6) and stranding of unknown cause (14). The majority of drowned birds were in good nutritional state, freshly dead and approximately 50% had freshly ingested fish in their proximal gut. Principle lesions were: gross distention of the heart and major veins with dark blood, intensely congested, swollen and oedematous lungs which released white frothy fluid when excised, watery fluid in the air sacs that ranged from clear to deep red depending on state of carcase preservation. PIB-affected birds were in good nutritional state; their pathology was largely consistent with that in confirmed drowning cases; it is likely that drowning was the ultimate cause of death. Birds affected by oil, adverse weather or that stranded due to unknown cause were all in poor or emaciated condition, the mean body mass of the guillemots and razorbills being, respectively, 53 and 57% of those that drowned. They had little or no food in their alimentary tracts and many showed evidence of enteric inflammation, haemorrhage and ulceration. None had fluid in their air sacs and none showed significant cardio-respiratory system lesions.
Drowned birds consistently showed a distinctive set of gross pathological lesions. When combined with contemporaneous observations, the pathology may be sufficient to permit a diagnosis of drowning, especially where a batch of freshly dead birds are examined. The observations in this study are likely to be of value when investigating stranding incidents, particularly where it is suspected that legislation aimed at protecting seabirds is not being complied with.
海鸟因人为原因导致的死亡，尤其是被困于渔具中，日益引起国际关注。本研究旨在描述溺亡于渔网中的海鸟的大体病理学特征，并将其与其他常见死因的病理学特征进行比较。
对1981年至2016年间在康沃尔郡搁浅的103只普通海雀、32只刀嘴海雀、37只鸬鹚和5只白嘴潜鸟进行了尸检。将确诊死于溺亡于渔网事件的鸟类（n = 95）的病理学与疑似溺亡（n = 6）、油污（n = 53）和聚异丁烯（PIB）污染（n = 3）、恶劣天气（n = 6）以及不明原因搁浅（14）的病例进行了比较。大多数溺亡鸟类营养状况良好，为新鲜死亡，约50%的鸟类近端肠道内有新鲜摄入的鱼类。主要病变包括：心脏和大静脉因淤血而显著扩张，肺强烈充血、肿胀且水肿，切除时会流出白色泡沫状液体，气囊内有液体，其颜色从清澈到深红色不等，取决于尸体保存状态。受PIB影响的鸟类营养状况良好；其病理学特征与确诊溺亡病例基本一致；溺亡很可能是最终死因。受油污、恶劣天气影响或不明原因搁浅的鸟类均处于不良或消瘦状态，普通海雀和刀嘴海雀的平均体重分别为溺亡鸟类的53%和57%。它们的消化道内几乎没有食物，许多鸟类有肠道炎症、出血和溃疡的迹象。它们的气囊内没有液体，也没有明显的心肺系统病变。
溺亡鸟类始终表现出一组独特的大体病理病变。结合同期观察，这些病理学特征可能足以做出溺亡诊断，尤其是在检查一批新鲜死亡鸟类时。本研究中的观察结果在调查搁浅事件时可能具有价值，特别是在怀疑有违反旨在保护海鸟的法规的情况下。
