Alabatros bycatch

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available at www.sciencedirect.com

journal homepage: www.elsevier.com/locate/biocon

´ Incidental and intentional catch threatens Galapagos waved albatross
Jill A. Awkermana,*, Kathryn P. Huyvaertb,d, Jeffrey Mangelc, Joanna Alfaro Shiguetoc, David J. Andersona
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Department of Biology, Wake Forest University,Winston-Salem, NC 27109-7325, USA Department of Biology, University of Missouri, St. Louis, MO 63121-4499, USA c Pro Delphinus, Octavio Bernal, 572-5, Lima 11, Peru d Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Ft. Collins, CO 80512-1474, USA
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A B S T R A C T

Article history: Received 14 April 2006 Received in revised form 19June 2006 Accepted 17 July 2006 Available online 26 September 2006 Keywords: Albatross Bycatch Harvest ´ Galapagos Peru ´ Fisheries Seabird Mark-resight Periodic matrix model ENSO

As large, long-lived seabirds with delayed and slow reproduction, albatrosses have low intrinsic mortality rates and are especially vulnerable to extinction from extrinsic sources of mortality such as fishery bycatch.Leg-band recovery information for waved albatrosses revealed mortality from both incidental catch and intentional catch for human consumption. Annual adult survival in 1999–2005, estimated from capture-mark-recapture data, was lower than historical estimates. This recent increase in adult mortality probably contributed to recent and dramatic shrinkage of the breeding population; periodic matrixmodels confirm that population growth rate is most sensitive to changes in adult survival. Banding data and recovery information also suggest that capture by fisheries is male-biased, which should reduce fecundity in this species with obligate bi-parental care. This new documentation of bycatch, harvesting, and associated demographic consequences provides reason for serious concern about thepersistence of the single breeding population of the waved albatross. Ó 2006 Elsevier Ltd. All rights reserved.

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Introduction

Albatrosses belong to the bird family most threatened by extinction, and mortality in fisheries has been linked to numerous albatross population declines (Croxall et al., 2005). Long-lived species with slow annual reproductive rates and low intrinsic mortality areespecially vulnerable to increased mortality from extrinsic sources (Wooler et al., 1992;

Holdaway and Jacomb, 2000). Fishery interactions threaten albatross species in subantarctic, subarctic, and subtropical oceans due to adult mortality as bycatch (Croxall and Gales, 1998). Satellite tracking studies identified the tropical Peruvian Upwelling as the principal foraging site of waved albatrosses(Phoebastria irrorata; Anderson et al., 2003). Until recently, this species was somewhat unusual in the apparent absence of threat from fisheries, since fleets near the

* Corresponding author: Tel.: +1 336 758 5573; fax: +1 336 758 6008. E-mail addresses: awkeja2@wfu.edu (J.A. Awkerman), huyvaert@cnr.colostate.edu (K.P. Huyvaert), jeffrey_mangel@yahoo.com (J. Mangel), jas_26@yahoo.com (J.A. Shigueto),da@wfu.edu (D.J. Anderson). 0006-3207/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.biocon.2006.07.010

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Peruvian upwelling comprise small artesanal boats with a few fishermen deploying handmade gear, and because near their ´ breeding grounds in the Galapagos Islands wavedalbatrosses do not display the boat-following behavior that makes some species more vulnerable to bycatch (Anderson and Cruz, 1998). Essentially the entire population of waved albatrosses ´ breeds on Isla Espanola, Galapagos (Harris, 1973; Anderson ˜ et al., 2002). Recent population estimates suggested a marked decline in breeding population size between 1994 and 2001 (Anderson et al., 2002). When we...
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