The number of threatened seabird species impacted by industrial-scale fishing has increased significantly in recent years. Negative impacts of industrial fisheries on marine ecosystems have been recognised by the UK government who recently banned sandeel fishing in UK waters. Sandeels are important prey for many marine predators including threatened seabird species such as Black-legged Kittiwakes and Puffins.
In South Africa, the results of a long-term Island Closure Experiment have confirmed that purse-seine fishery closures would result in meaningful population improvements to African Penguins. The purse-seine fishery is the largest fishery by volume of fish extracted in South Africa, targeting mainly sardine and anchovy, the principle prey of African Penguins and other threatened seabird species that are endemic to the Benguela Upwelling Ecosystem. These findings were supported by an expert panel of scientists in 2023 which was commissioned by the South African government to resolve a long-standing impasse between conservation scientists and fisheries stakeholders regarding proposals to implement long-term closures around the last remaining large penguin colonies in South Africa’s inshore waters.
Certain recommendations by the expert panel were implemented by the then Minister of the Department of Forestry, Fisheries and the Environment, Minister Barbara Creecy. These included closures around six major colonies for 10 years with a review after six years. However, although the panel endorsed a trade-off mechanism to resolve disputes between stakeholders on the delineation of the closures, Minister Creecy did not adopt the recommended trade-off mechanism but instead instituted closure designs that pre-dated the panel findings, pending further efforts to get conservation and pelagic fishing industry stakeholders to agree on mutually acceptable closures. Just prior to the start of the 2024 fishing season, the Minister announced that the ‘interim’ closures would remain in place for the long term given that stakeholders, despite further negotiations, failed once again to reach a consensus.
Our paper recently published in the ICES Journal of Marine Science applies the recommended trade-off mechanism to assess the adequacy of the current island closures in terms of their coverage of important African Penguin foraging areas and weighs these up against alternative closure delineations in the trade-off space, relative to their predicted impacts on fishery catch losses. The candidate closures include delineations generated from GPS tracking data using methods previously adopted to demarcate marine Important Bird and Biodiversity Areas (mIBAs) to determine core foraging areas, and wider penguin foraging ranges. By applying the trade-off mechanism, we are able to identify a ‘balance point’ to guide the selection of closure delineations that maximise benefits associated with penguin spatial representativity while minimising costs (catch loss) to the fishing industry.
Maps showing the location of the 6 African Penguin breeding colonies included in the assessment including the current purse-seine fishery no-take zones and the location of fishing catches between 2011 and 2020.
The results for six colonies that currently hold 76% of the global population of African Penguins demonstrate that the current closures are largely inadequate and, therefore, unlikely to alleviate resource competition. Four of these closure extents, around Robben Isand, Stony Point, Dyer Isand and St Croix Island, protect ≤50% of the African Penguins’ core foraging areas while having relatively little to no cost to the fishing industry. The remaining two include the largest global colony of African Penguins on Dassen Island. Although the Dassen Island closure protects a considerable proportion of core foraging area, it does not include a critical part of the penguins’ core feeding grounds to the north of the colony where there has been significant concentrated fishing effort in recent years. This is also the area from where anchovy recruits migrate southward into the penguins’ larger habitat during the peak of their breeding season. The only foraging area that has been afforded adequate protection is around Bird Island in Algoa Bay which has been subjected to the least fishing pressure of all six colonies.
Location of no-take zone options proposed for Stony Point since 2008 and corresponding trade-off assessment for different fish stocks caught by the purse-seine fishery. Trade-off plots include no-take zone options relative to their corresponding benefits to penguins (penguin utility score) and costs to fisheries (catch loss).
The findings of the study are critical to slowing the rate of decline of African Penguin numbers which have plummeted in recent years: there were > 1.5 million birds in the early 20th century compared to an estimated 22 700 birds (9900 breeding pairs) in 2023. The global population has almost halved in the last decade. A recent assessment of their conservation status using the IUCN Red Listing criteria shows that the African Penguin qualifies for uplisting to Critically Endangered with a predicted extinction date, if current trends persist, in 2035. Undernourished penguins are vulnerable to the range of ongoing threats including predation, oil pollution, vessel noise and disease. Management measures to curb such threats and better protect African Penguins are included in a draft Biodiversity Management Plan which is also intended to guide the coordination of efforts by various institutions. The Plan has yet to be finalised and despite existing conservation efforts the population continues to decline. The availability of prey, mainly sardine and anchovy, has been consistently linked to the survival, breeding success and foraging performance of the African Penguin. Yet effective long-term measures to manage these fish stocks sustainably, in line with an effective ecosystem approach to fisheries management, has not been forthcoming. Implementation of meaningful closures aligned to important penguin foraging areas, such as those proposed in our paper, is recommended as an urgent conservation intervention to alleviate resource competition around African Penguin colonies. This intervention, coupled with harvest allocations that ensure long-term sustainability of sardine and anchovy stocks for marine predators, will go a long way in helping to ensure the survival of Africa’s only penguin species.
Read the full paper:
Alistair M McInnes, Eleanor A Weideman, Tegan Carpenter-Kling, Peter Barham, Murray Christian, Kirsten Day, Jacqueline S Glencross, Christina Hagen, Alison Kock, Cloverley Lawrence, Katrin Ludynia, Azwianewi Makhado, Lorien Pichegru, Lynne Shannon, Richard B Sherley, Craig Smith, Antje Steinfurth, Nicky Stander, Leshia Upfold, Lauren Waller (2024). Commercial fishery no-take zones for African penguins minimize fisheries losses at the expense of conservation gains, ICES Journal of Marine Science, fsae109. https://doi.org/10.1093/icesjms/fsae109