Impacts of fisheries and climate on albatross demography

Lead Research Organisation: NERC British Antarctic Survey
Department Name: Science Programmes

Abstract

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

Planned Impact

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.

Publications

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Gianuca D (2017) Global patterns of sex- and age-specific variation in seabird bycatch in Biological Conservation

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Pardo D (2017) Additive effects of climate and fisheries drive ongoing declines in multiple albatross species. in Proceedings of the National Academy of Sciences of the United States of America

 
Description Climatic and anthropogenic factors are often considered to drive population declines in many top-predators, but how their influences combine remains unclear. Albatrosses are particularly threatened, as slow life-histories provide little resilience to environmental change, and extensive foraging ranges expose birds to incidental mortality in multiple fisheries. The albatross community at South Georgia includes substantial proportions of global numbers of three species, all of which have declined dramatically over the last 35 years. Examining key demographic rates in juveniles and adults showed that although at-sea distributions, life-histories and responses to fisheries were species-specific, bycatch generally drove the declines, especially when combined with extreme climate (little sea ice, El Niño). Additionally, changing climate (wind patterns, increasing sea temperature) affected the population recovery potential. The results help focus future management actions for these high priority populations, and underline the power of this approach for quantifying relative importance of variables in a comparative framework.

Life-history theory predicts that in long-lived species, individuals reduce current reproductive effort if environmental conditions deteriorate to ensure their future survival and reproductive potential. However, when environmental variability is intense, and human-activities have a direct impact, populations will decline and mechanisms of demographic resilience may appear. Pre-breeders and adult non-breeders can represent more than half the population in long-lived species, and might exhibit behavioural changes that buffer the rate of decline in the population. The population of grey-headed albatrosses at South Georgia, which constitutes 50% of global numbers, has declined by 60% in the last 30 years. They typically breed biennially but individuals exhibit heterogeneity in breeding frequency as well as recruitment age that can occur as late as 20 years old. We hypothesised that in response to a decline in population size, pre-breeders may recruit earlier and adults may breed more often. Using a multi-event capture-mark-recapture model with 6000 individuals ringed since 1976, we detected that recruitment rate was twice as high in some cohorts than others while mean recruitment age advanced by up to two years. Recruitment rate was negatively related to population size, suggesting density-dependence. Non-breeders that usually attended the colony during the breeding season had significantly higher survival, and tended to have higher breeding success than those that mostly or always stayed at sea. They were less affected in years of poor environmental conditions and showed different senescence trajectories suggesting important ecological and evolutionary consequences. Matrix population models encompassing both those mechanisms in various scenarios led to an increase in the population growth rate by up to 2%. However environmental conditions have worsened in the last decade and appeared to be cancelling out demographic resilience from both pre- and non-breeders. We present clear evidence that individuals in long-lived populations can modify their life-history strategies, which to some extent safeguards from the population decline. For methodological reasons, pre- and non-breeders are too often overlooked in population models; however, the demographic resilience mechanisms they offer might be a key factor in the conservation of threatened populations and species.
Exploitation Route Results and conclusions from this study will form the basis of a suite of journal papers and presentations at scientific conferences. They will also be communicated in the form of advice to stakeholders in UK govt. (Defra, JNCC, Foreign and Commonwealth Office), and NGOs (BirdLife International and others), and working group papers (tailored as appropriate with specific analyses and recommendations) to meetings of international treaties (ACAP, SCAR, CCAMLR) and fisheries commissions in order to develop responsible conservation management policies. 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 fisheries 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. We anticipate widespread public interest in the results given the charismatic nature of the study species and the high media profile of fisheries and climate change.
Sectors Environment

 
Description Provided advice to BirdLife International on IUCN Red Data list updates for albatrosses and petrels (July-Sept. 2016). Contributed advice and graphs for Albatross Species Actions Plans commissioned by the Government of South Georgia and the South Sandwich Islands (May 2016) Contributed text and comments to UK implementation report to the Agreement on the Conservation of Albatrosses and Petrels (Jan. 2016)
First Year Of Impact 2016
Sector Environment
Impact Types Societal

 
Description Conserving the world's threatened seabirds; the contribution of research by British Antarctic Survey to the international Agreement on the Conservation of Albatrosses and Petrels (ACAP)
Geographic Reach Multiple continents/international 
Policy Influence Type Participation in a advisory committee
Impact ACAP was ratified in 2004 and aims to improve the conservation of the 29 listed species. These pelagic seabirds are amongst the most threatened of all groups of birds, mainly reflecting unsustainable levels of incidental mortality (bycatch) in commercial fisheries and, for some, the additional impacts of introduced mammals at colonies. BAS researcher, Dr. Richard Phillips, has been an adviser to the UK delegation to ACAP since the first Advisory Committee (AC) meeting in 2005, and convenor of the Populations and Conservation Status working group since 2009. BAS holds amongst the most comprehensive long-term datasets available on population trends, demography and at-sea distribution of albatrosses and giant petrels. These formed the basis of submissions to ACAP Advisory Committee meetings in 2016 and 2017 and were incorporated into a range of products including summaries of global population status that highlighted ongoing declines, headline indicators used to assess the progress of ACAP, and papers submitted to fisheries regulatory bodies. A paper with Dr Phillips as lead author that summarised progress and priorities of ACAP in terms of conservation research and management of the listed species was published in Biological Conservation in 2016.
 
Description NERC Life Sciences Mass Spectrometry Facility
Amount £13,060 (GBP)
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 02/2016 
End 03/2016
 
Description Research Scholarship - Cambridge Philosophical Society
Amount £1,000 (GBP)
Organisation Cambridge Philosophical Society 
Sector Learned Society
Country United Kingdom
Start 05/2016 
End 08/2016
 
Description Student Travel Grant - Darwin College
Amount £300 (GBP)
Organisation University of Cambridge 
Sector Academic/University
Country United Kingdom
Start 12/2013 
End 12/2014
 
Description Student travel grant - Marine Biological Association
Amount £500 (GBP)
Organisation Marine Biological Association 
Sector Learned Society
Country United Kingdom
Start 09/2015 
End 10/2015
 
Description Collaboration with Peter Ryan 
Organisation University of Cape Town
Department Percy FitzPatrick Institute of African Ornithology
Country South Africa 
Sector Academic/University 
PI Contribution Analyses comparing habitat preferences of grey-headed albatrosses from colonies in the South Atlantic and Indian oceans
Collaborator Contribution Peter Ryan from the University of Cape Town, South Africa, provided tracking data and expert advice that has assisted towards the publication of a paper (Clay et al. 2016).
Impact Scientific paper (Clay et al. 2016). Web article on the results "Albatrosses forage in different areas when on migration", URL - https://phys.org/news/2016-07-albatrosses-forage-areas-migration.html
Start Year 2013
 
Description 'Look into the Polar Light' event 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact 'Look into the Polar Light' event for the Cambridge Science Festival at the Scott Polar Museum
Year(s) Of Engagement Activity 2015
 
Description School Visit (Comberton College) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Talk to raise awareness on the impact of Human activities on biodiversity extinction and more specifically the role we have as citizens to influence fisheries and climate change
Year(s) Of Engagement Activity 2017
 
Description School Visit (Hills Road Sixth Form) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Talk to raise awareness on the impact of Human activities on biodiversity extinction and more specifically the role we have as citizens to influence fisheries and climate change
Year(s) Of Engagement Activity 2016
 
Description YouTube channel 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Channel to inspire future generations to take care of our planet by finding their own solutions and benefits
Year(s) Of Engagement Activity 2015,2016,2017
URL https://www.youtube.com/channel/UCrkLiYviYe_65WfrHKaMNrw