|ALBATROZ - Learning from the flight of the albatross: causes and consequences of individual foraging strategies, with links to demography, oceanography and fisheries|
Paulo Catry (ISPA Instituto Universitário)
CESAM Responsible researcher - José Pedro Granadeiro
Programme - PTDC/MAR/099366/2008
Execution dates - 2009-11-01 - 2012-10-31 (36 Months)
Funding Entity - FCT
Funding for CESAM - 64770 €
Total Funding - 146340 €
Proponent Institution - ISPA Instituto Universitário
Universidade de LisboaMuseu Nacional de História Natural
Seabirds are major marine predators, with an annual food consumption approaching the global catch by all marine fisheries. Seabirds are relatively easy to study and thus they are increasingly being used for environmental monitoring, including the assessment of the effects of climate change. Human fisheries interact with seabirds in important ways, e.g. by providing discards, competing for prey, changing ecosystem structure and causing significant seabird mortality in fishing gear. For these and other reasons, many seabirds are globally threatened, and they are increasingly being taken into account in the ecosystem-based management of fisheries and in the design of marine protected areas.
However, for seabirds to be effectively used in spatially and temporally explicit ocean monitoring and seascape management there is a need for a better understanding of their responses (demographic, ecological, physiological and behavioural) to environmental variation at several relevant scales.
Our objectives are to achieve a very detailed understanding of 1) the factor determining the individual foraging strategies of Blackbrowed albatrosses (BBA) Thalassarche melanophris, 2) the mechanisms through which these factors operate and 3) the implications of individual decisions on fitness and on population demography.
We will develop new methods to study the interaction of BBA and fisheries at a level of detail never attempted before. We will use accurate GPS and immersion loggers (Mk7, also recording SST) for the fine details of bird movement and activity. We will use the Falklands Fisheries Department VMS (vessel monitoring system) data and electronic logbooks to get similarly detailed information (resolution <10 m, each 10 min) on all fishing activity in Falkland waters. The Falklands provide a particularly suited system to this end, as all fishing vessels are monitored with VMS. Using analytical tools such as first-passage time analysis, we will characterise consistent differences in area restricted search (ARS) patterns of birds associated with fisheries and birds feeding from other sources. If successful, this will allow the study of bird and fisheries interactions even in areas with limited or no VMS data. We will concurrently obtain stable isotope signatures of fishery discard products and of "natural" albatross prey. By using conventional dietary studies, isotope measurements and mixing models, we will develop further tools to measure the degree of interactions of birds and fisheries, both at the population and individual level.
We will then proceed with the study of the causes and consequences of albatross foraging behaviour. We will look at individual
GPS and activity recorder data from will be used to create a spatial and temporally explicit understanding of BBA foraging in the Southern Patagonian Shelf, with relevance to seascape management and the creation of marine protected areas. Bird distribution will be modelled using GIS and advanced statistical tools in relation to remotely sensed derived data (SST, wind, chlorophyll-a concentration), bathymetry, fisheries and distance to colony. Finally, we will evaluate the consequences of the foraging choices of albatrosses and their interactions with environmental variability. Questions to be addressed include: a) does foraging specialisation affect fitness correlates (eg. egg size, chick growth and survival, adult body condition)? b) does the degree of foraging specialisation vary in years of contrasting environmental conditions (SST, availability of discards, etc)? c) Which parameters are better correlated with environmental variables and short-term climate fluctuations and, hence, are more likely to convey interesting information for environmental monitoring? Parameters will include demographic (adult survival, breeding success), ecological (diet composition), physiological (egg size, chick growth, adult condition) and behavioural (foraging trip and brood-guard duration) variables.