PhD Code: MARES_27_2010:
- Host institute 1: P7 - Plymouth University
- Host institute 2: P11 - Université Pierre et Marie Curie (UPMC)
- T4 - Natural resources : overexploitation, fisheries and aquaculture
- Stephen Votier
- Henri Weimerskirch
One of the most pervasive impacts of commercial capture fisheries are the accidental death of huge numbers of marine predators, which become entangled in fishing gear when scavenging for food in the form of fisheries waste. This mortality (termed bycatch) is unsustainable and has drastically reduced populations of many apex marine predators (Lewison et al. 2004). Understanding and mitigating the impacts of bycatch mortality is an issue of global conservation concern, and forms the central thesis of this proposal.
Annually, tens of thousands of albatrosses become accidentally hooked and drowned by longline fisheries (Gales et al. 1998) or entangled with trawl gear (Baker et al. 2007). These losses are closely linked with precipitous population declines and despite mitigation attempts, the future for albatross populations remains bleak. However recent work has shown that individual seabirds specialise in scavenging for fishery discards (Votier et al. 2010), indicating that mortality risks are not evenly spread within the population. Understanding the extent and nature of such specialisations could have significant conservation implications, but have thus far remained virtually unstudied.
Aims & Objectives: The aim of this project is to determine the degree to which individual albatrosses specialise as scavengers from fishing boats (compared with natural prey) and consider the implications of this for the management of mutually co-existing fisheries and seabird populations. These aims will be met via the following objectives:
1. To collect high-resolution at-sea foraging data from breeding Campbell and grey-headed albatrosses during repeat trips within the same year and among consecutive years
2. To quantify the extent of foraging specialisation in relation to the location of fishing vessles (using the Vessel Monitoring System [VMS])
3. Using analysis of regurgitated prey and Bayesian stable isotope mixing models, assess the relative contribution of fishery discards to the diet of individual albatrosses within the same year and among consecutive years
4. To quantify the extent of foraging specialisation in relation to the ingestion of fishery discards compared to naturally occurring prey
5. Investigate factors that might influence variation in specilisation on scavenging behaviour (e.g. species, age, sex, body condition)
6. Using results from 1-6, assess the relevance of individual foraging specialisations for albatrosses bycatch
Study species & location. Research will be conducted at Campbell Island, New Zealand, which support important populations of Campbell (Thalassarche impavida) and grey-headed albatross (T. chrysostoma). These species are prone to bycatch and are the subject of a long-term tracking project run by the National Institute of Water & Atmospheric Research (NIWA), Wellington, NZ.
Methods. GPS loggers (provided by NIWA) will be deployed on breeding adults during incubation and chick rearing for multiple foraging trips both within and among years. At-sea behaviour will be compared with VMS data on the location of fishing vessels, as well as and other ecologically relevant covariates. During handling any spontaneous regurgitates will be collected, identified and measured, before being kept for stable isotope analysis. Blood will be taken from all captured birds (under licence), and used for both sex determination (using PCR techniques) and stable isotope analysis. Benthic fish that form a significant component of discards are beyond the diving range of albatrosses and are also isotopically distinct from naturally occurring prey (Votier et al. 2010). The project will use a combination of Bayesian isotope mixing models and analysis of regurgitates to estimate the relative contribution of fishery discards, compared with natural prey. Therefore the student will receive first-hand experience of a number of state-of-the-art methodologies, which will be used to determine the degree of individual specialisation in relation to fisheries.
Feasibility. This proposal fits into an established long-term programme of albatross research on Campbell Island, where two years of GPS tracking data have already been collected (providing an insurance against any unforseen fieldwork problems). Moreover, this proposal represents a relatively straightforward question that can easily be addressed by the programme of research, that is of major conservation significance. Therefore this represents a low risk and high gain project.
Supervisory team. The candidate will be based at the University of Plymouth with Stephen Votier, an early-career scientist working mostly on seabird biology as well as ecological applications of stable isotopes. He has published 29 papers that have received 522 citations and currently supervises 4 PhD students. The student will also spend at least 6 months at the Ecology of Birds & Marine Mammales group, Chizé. Head of this team is Henri Weimerskirch who is internationally renowned for his research in this field having published 198 papers, which received 6561 citations, and has 15 PhD completions. In addition, the fieldwork will be overseen by David Thompson at NIWA who has published 37 papers, receiving 1232 citations and has 5 PhD completions. In summary the student will be supported by a very strong team with a proven track record in PhD supervision, over 25 years experience working in the Sub-Antarctic, and unparalleled experience in the field of seabird ecology.
Baker GB, Double MC, Gales R, Tuck GN, Abbott CL, Ryan PG, Petersen SL, Robertson CJR, Alderman R (2007) A global assessment of the impact of fisheries-related mortality on shy and white-capped albatrosses: Conservation implications. Biol Conserv 137: 319-333
Gales R, Brothers N, Reid T (1998) Seabird mortality in the Japanese tuna longline fishery around Australia, 1988-1995. Biol Conserv 86: 37-56
Lewison RL, Crowder LB, Read AJ, Freeman SA (2004) Understanding impacts of fisheries bycatch on marine megafauna. Trends Ecol Evol 19: 598-604
Votier SC, Bearhop S, Witt MJ, Inger R, Thompson D, Newton J (2010) Individual responses of seabirds to commercial fisheries revealed using GPS tracking, stable isotopes and vessel monitoring systems. J Appl Ecol 47: 487-497
If funded, this studentship would be expected to generate a number of important publications relevant to ecology, conservation and fisheries management. The supervisory team has experience in producing papers in top scientific journals (e.g. Nature 7, Science 2, PNAS 6) as well as in the most highly ranked ecological journals. In addition to this proven publication track-record, many of these papers were jointly written with post-graduate students. Given the importance of the topic to conservation biology (and the relevance of individual specialisation to behavioural ecology) it is anticipated that 2-3 papers will be published in good quality biology or ecology journals such as Proceedings of the Royal Society B, Journal of Animal Ecology and Journal of Applied Ecology, as well as 2-3 in more specialised journals. As well as producing published papers on this topic, the candidate will disseminate with work via meetings with stakeholders (particularly relevant in New Zealand), annual MARES meetings, fellow academics at workshops and international conferences, as well as to the community with the respective host institutions. In terms of outreach to the public, any successful candidate would be expected to report findings to public meetings via the University of Plymouth Marine Institute as well as to target exposure via the mass media. Recently interest in research investigating interactions between seabirds and fisheries in the UK (led by Votier), lead to a number of radio programmes, articles in the popular press as well as television programmes broadcast on the BBC. Given the charismatic nature of albatrosses, it is likely that the current proposal will attract similar (if not more) media attention and the press office at the University of Plymouth we actively promote such work.