The Cape Gannet Morus capensis is one of several seabird species endemic to the Benguela upwelling ecosystem (BUS) but whose population has recently decreased, leading to an unfavourable IUCN Red List assessment. Application of ‘JARA’ (‘Just Another Red-List Assessment,’ a Bayesian state-space tool used for IUCN Red List assessments) to updated information on the areas occupied by Cape Gannets and the nest densities of breeding birds at their six colonies, suggested that the species should be classified as Vulnerable. However, the rate of decrease of Cape Gannets in their most-recent generation exceeded that of the previous generation, primarily as a result of large decreases at Bird Island, Lambert’s Bay, and Malgas Island, off South Africa’s west coast (the western part of their range). Since the 1960s, there has been an ongoing redistribution of the species from northwest to southeast around southern Africa, and ∼70% of the population now occurs on the south coast of South Africa, at Bird Island in Algoa Bay, on the eastern border of the BUS. Recruitment rather than adult survival may be limiting the present population; however, information on the seabird’s demographic parameters and mortality in fisheries is lacking for colonies in the northern part of the BUS. Presently, major threats to Cape Gannet include: substantially decreased availability of their preferred prey in the west; heavy mortalities of eggs, chicks and fledglings at and around colonies, inflicted by Cape Fur Seals Arctocephalus pusillus and other seabirds; substantial disturbance at colonies caused by Cape Fur Seals attacking adult gannets ashore; oiling; and disease.

海角塘鹅桑属是本格拉上升流生态系统（BUS）特有的几种海鸟物种之一，但其种群最近有所减少，导致对IUCN红色名录的评估不利。使用“ JARA”（“另一个红名单评估”，一种用于IUCN红色名单评估的贝叶斯状态空间工具）来更新有关Gannets角占据的面积以及六个鸟类的繁殖鸟巢密度的最新信息，建议将该物种归类为“弱势”。但是，海角塘鹅最近一代的下降速度超过了前几代，主要是由于南非西海岸（西南部）的伯德岛，兰伯特湾和马尔加斯岛的下降幅度较大。他们的范围）。自1960年代以来，在非洲南部从西北到东南，该物种一直在不断地重新分布，现在约有70％的人口分布在南非的南海岸，即布宜诺斯艾利斯东部边界的Algoa湾的伯德岛。招聘而不是成年人的生存可能会限制现有的人口；但是，BUS北部地区的殖民地缺乏有关海鸟的人口统计参数和渔业死亡率的信息。目前，对塘鹅角的主要威胁包括：西部地区首选猎物的供应大大减少；Cape Fur Seals在殖民地及其周围造成大量的鸡蛋，雏鸡和雏鸟死亡 在公共汽车的东部边界。招聘而不是成年人的生存可能会限制现有的人口；但是，BUS北部地区的殖民地缺乏有关海鸟的人口统计参数和渔业死亡率的信息。目前，对塘鹅角的主要威胁包括：西部地区首选猎物的供应大大减少；Cape Fur Seals在殖民地及其周围造成大量的鸡蛋，雏鸡和雏鸟死亡 在公共汽车的东部边界。招聘而不是成年人的生存可能会限制现有的人口；但是，BUS北部地区的殖民地缺乏有关海鸟的人口统计参数和渔业死亡率的信息。目前，对塘鹅角的主要威胁包括：西部地区首选猎物的供应大大减少；Cape Fur Seals在殖民地及其周围造成大量的鸡蛋，雏鸡和雏鸟死亡弓形虫和其他海鸟；因海角海豹袭击岸上成年塘鹅而对殖民地造成的重大干扰；注油; 和疾病。