Impacts of fisheries and climate on albatross demography

Climate change and fisheries are major threats to marine biodiversity. Climate influences conditions in the ocean, including levels of primary productivity and acidification, and may eventually affect the routes and strength of ocean currents. This has impacts on the distribution and abundance of organisms at the bottom of food chains, with consequent effects on their predators. Recent research has revealed changes in the extent and duration of winter sea-ice formation in the Antarctic, resulting in a dramatic reduction in Antarctic krill. As this is a key prey for many whales, seals and seabirds, the decline has had adverse effects on their breeding frequency, success and survival.

Marine fisheries compete with natural predators and unintentionally catch many non-target (bycatch) species. High bycatch levels have been linked to worldwide declines of seabirds, marine mammals, turtles and sharks. However, fisheries can also bring benefits, as scavengers exploit the fish offal and bycatch discarded by vessels. It is therefore difficult to judge their full impacts without detailed knowledge of the type and extent of interaction. We also need to understand the influence of global climate change, which is predicted to greatly increase the variability and unpredictability of environmental conditions and hence availability of marine resources.

Seabirds are major consumers, and as top predators, their populations reflect changes occurring further down food chains, which are in turn influenced by those in the wider environment. Many are threatened, particularly albatrosses which are vulnerable to any unnatural mortality because they fledge one chick only every 1 or 2 years. Given their vast foraging ranges, they overlap with and are killed in multiple fisheries. Recognition of this international problem led to the establishment of a dedicated albatross and petrel conservation agreement (ACAP), ratified by the UK. Seven of the eight albatross populations breeding in the UK Overseas Territories in the South Atlantic are declining (a higher proportion than in any other sector of the Southern Ocean). High bycatch rates are a major contributing factor. Only for black-browed albatross at South Georgia is there evidence of impacts of environmental change; however, there have been no comparable studies of the other species.

The wandering, grey-headed and black-browed albatrosses at South Georgia are of global importance, and include two of the five priority populations for conservation identified recently by ACAP. Observed changes in productivity and other population parameters suggest that environmental factors and fisheries affect each species in differing ways, reflecting differences in distribution and life-styles. Studies of seabirds elsewhere have found links between environmental changes and annual variation in breeding success and, in a minority of cases, adult survival, but these depended on the species. Recent modeling carried out on behalf of the Atlantic tuna commission concluded that fisheries are having detrimental impacts on two species from South Georgia, but did not consider grey-headed albatross, nor the implications of changing environmental conditions. There are also two major unresolved issues for these populations, (i) a dramatic drop in survival of chicks from fledging to first return, and (ii) the demographic implications of differing at-sea distributions of males and females, including a sex ratio imbalance if it affects survival.

A comprehensive analysis of the contributions of climate and fisheries impacts to differences in survival, breeding frequency and success of these species is not only a high conservation priority, but an outstanding opportunity to improve our understanding of the implications of climatic variation in a region changing at an unprecedented rate. The analysis will provide robust scientific grounds to improve environmental management, particularly at fisheries regulatory bodies

In addition to strictly academic beneficiaries, our results will be of interest or utility for the following groups.

1. UK policy makers (in Defra, JNCC, FCO; see supporting letters) with responsibilities for overseeing the UK contribution to multilateral environmental agreements (MEAs), including the Convention on Biological Diversity, Convention on Migratory Species and Agreement on the Conservation of Albatrosses and Petrels (ACAP), under which there are obligations to address global biodiversity loss. The results will also be of high relevance for UK policy makers attending fisheries commissions and their associated working groups on ecological impacts. There has been considerable recent emphasis on developing ecological risk assessments and instituting ecosystem-based approaches to management in order to minimize the impact of fisheries on non-target species. Our project should provide clear indications of the relative contribution of bycatch, discard availability and climate change to observed changes in population size and demography of albatrosses breeding in the UK Overseas Territory of South Georgia, and results from the associated studentship will identify the areas and times of greatest risk from particular fleets. Thus, UK delegates to MEAs and fisheries meetings will be able to make informed decisions about which species are most vulnerable and which fleets or regions should be considered priorities for introduction of better management and mitigation protocols, and observer programmes.

2. Conservation advocates based at UK and foreign NGOs, including BirdLife International Global Seabird Programme and RSPB, which are the key UK bodies (see supporting letters), and Falklands Conservation, NZ Forest and Bird, Birds Australia, Projecto Albatroz (Brazil), Aves Argentinas and Proyecto Albatros y Petreles (Uruguay) that are involved in promoting bycatch issues and provision of advice on best practice mitigation techniques both to their domestic fisheries operators and at international fisheries meetings. It is often essential to provide compelling evidence of wider impacts on non-target species before fisheries operators will employ bycatch mitigation measures; this is important at all levels, from grass-roots engagement with the skippers of small artisanal vessels (which may individually catch few birds), to the companies operating major fishing fleets in the High Seas. NGOs also use the authority associated with published studies in international journals that underline the wider population consequences of bycatch to justify continued funding of their organisations by government, private sector or charitable foundations.

3. Foreign policy makers representing parties to the agreements and conventions listed above. As with their UK counterparts, they require the best available information on compounded impacts of climate and fisheries on different species and populations. Albatrosses disperse widely particularly during the nonbreeding season, so success in reversing the population declines of the various species at South Georgia requires the identification of the flag states responsible, and improved bycatch mitigation in their EEZs, and in their distant water fleets operating in the High Seas.

4. The wider public with interests in the impacts of fisheries and climate on biodiversity in general, and on bird conservation in particular.

The PI is closely involved in a number of key international conventions and other fora (see Previous Track Record in the Case for Support), and engages in regular dialogue with the relevant UK government bodies. He also has close working links with BirdLife International, a suite of overseas NGOs engaged in highlighting seabird bycatch issues in their domestic waters, and leading albatross researchers working on other Southern Ocean populations. It will therefore be possible to ensure wide and rapid communication of the results of this project to these beneficiaries.