Exporting the problem: Issues with fishing closures in seabird conservation

COPELLO S, G BLANCO, JP SECO PON, F QUINTANA & M FAVERO

Marine Policy

Elsevier

Año: 2016 vol. 74 p. 120 - 127

0308-597X

Fisheries pose the most important threats affecting the survival of most albatrosses and petrels species around the globe. The fishing management could have a strong effect on several traits of seabirds? ecology such as the foraging behavior and also the interactions with the vessels. The Argentinean Economic Exclusive Zone holds an extensive year-round fishing closure of some 120.000 km2 where trawling is banned. The consequent concentration of trawlers? fishing effort in the boundary of this area and strong overlapping with the distribution of albatrosses triggered the question of a potential exacerbated negative effect of bycatch in such border area. Hence, this study was conducted having as main objectives: (1) the analysis of the effect of fishing closures on the flight patterns of Black-browed Albatrosses (BBAs) and Southern Giant Petrels (SGPs) as case study species known to extensively interact with trawlers, and (2) the analysis in space and time of seabird-fisheries interactions (i.e. contacts with the fishing gear as a proxy of risk of mortality) in relation to the vicinity to fishing closure. A total of 55 satellite transmitters were deployed on BBAs and SGPs between 1999 and 2013. Discrete behavioral modes (foraging vs. transiting) were inferred inside and outside the closure area from satellite movement data using state-space models. Seabird bycatch data were obtained from on-board observers. Kernel analysis for each behavioral mode and the seabird interaction rates were used to determine the spatial density. Seabirds largely foraged in the outside border of the fishing closure where the fishing activity also concentrated, while transiting occurred both inside and outside of the fishing closure. Seabird-fishery interactions were significantly concentrated in the external boundary of the fishing closure area in comparison with other areas along the Patagonian Shelf. The study highlights that, although by definition seabird bycatch in closure areas is nil, in practice the ?exporting effect? due to the concentration of both fishing effort and seabird foraging in border areas may substantially increase seabird by-catch in the immediate neighboring waters. Hence, the design of conservation management measures for seabird by-catch should contemplate specific regulations to address these negative side effects of concentrating both fishing and seabird activity in border areas.