Fisheries bycatch mitigation measures as an efficient tool for the conservation of seabird populations

• Published in: Journal of Applied Ecology
• Main Authors: Dasnon, Anaïs, Delord, Karine, Chaigne, Adrien, Barbraud, Christophe
• Other Authors: Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Réserve Naturelle Nationale des Terres Australes Françaises, TAAF
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: conservation; measures capture–mark–recapture demersal; longline; fisheries population; dynamics procellariforms southern; Indian; Oceanwhite-chinned petrel; [SDE]Environmental Sciences; Possession Island; Sea ice
• Online Access: https://hal.science/hal-03671563; https://doi.org/10.1111/1365-2664.14189

International audience 1. The impact of industrial fisheries on marine biodiversity is conspicuous in largepelagic vertebrate's fisheries bycatch. In seabirds, this led to the decline of manypopulations since the 1980s following the rise of global fishing effort. Bycatchmitigation measures were implemented since the 2000s, but their effects on theconcerned seabird populations remain poorly quantified and understood.2. We studied the effects of bycatch mitigation measures on the demography ofthe white-chinned petrel, one of the most bycatch impacted seabirds whosepopulations suffered dramatic declines before the implementation of mitiga-tion measures. To do so we (a) built multi-event capture–recapture models toestimate the demographic parameters of a population from Possession Island(southern Indian Ocean) over 30 years, (b) assessed the effect of climate andfishery covariates on demographic parameters, (c) built a population matrixmodel to estimate stochastic growth rate according to the management in fish-eries bycatch and (d) estimated changes in breeding population density usingdistance sampling data.3. The population declined from the 1980s to the mid-2000s, while trawl andlongline fisheries occurred with no bycatch mitigation measures. The negativeeffects of fishery bycatch through additive mortality and of rat predation onbreeding success were likely the main drivers of this decline.4. Both modelled population growth rate and observed breeding densities showedan increase since the mid-2000s. We explained this trend by the improvementin survival probability following implementation of fishery bycatch mitigationmeasures and in breeding success probability with the local control of the ratpopulation and changes in sea ice conditions on foraging grounds.5. Synthesis and applications. We provide a holistic approach to assess the effects ofmanagement measures by analysing datasets from sampling methods commonlyemployed in seabird studies. Our conclusions should encourage the eradicationof invasive predatory ...