CCAMLR Science, Vol. 4 (1997): 75-87 THE FORAGING RANGE OF ADELIE PENGUINS - IMPLICATIONS FOR CEMP AND INTERACTIONS WITH THE KRILL FISHERY K.R. Kerry, J.R. Clarke, S. Eberhard, H. Gardner, R.M. Lawless, R. Tremont and B.C. Wienecke Australian Antarctic Division, Channel Highway Kingston 7050, Tasmania, Australia S. Corsolini, S. Focardi, E. Franchi Dipartimento di Biologia Ambientale, Universita di Siena via della Cerchia 3,53100 Siena, Italy D. Rodary Centre dlEcologie et Physiologie Energetique CNRS, 23 Rue Becqueral, 67087 Strasbourg, France R. Thomson Department of Zoology, University of Cape Town Rondeboscl~7700, South Africa Abstract This paper presents a summary of the foraging locations of Adelie penguins, determined by satellite tracking, at seven widely-spaced breeding colonies along the coast of eastern Antarctica between 55"E (Enderby Land) and 175"E (Ross Sea). Adelie penguins feeding chicks regularly travelled up to 120 km offshore to the continental shelf and returned with krill, Etlplzausza superba. Locations of penguins on foraging trips were compared with historical records of fine-scale krill catch data for the regions of interest. The potential for overlap with krill fishing occurs particularly where ice conditions permit the fishing fleet to approach the edge of the continental shelf or where penguins forage downstream from the fishery. It is suggested that the potential for overlap between foraging areas of Adelie penguins and fishable concentrations of krill be investigated before a decision is made to establish a new CEMP site. Resume L'auteur presente une recapitulation des secteurs d'approvisionnement determines par des suivis par satellite de manchots Addie de sept colonies de reproduction largement espacees le long de la c6te est de lfAntarctique, entre 55"E (terre Enderby) et 175OE (mer de Ross). Les manchots Adelie nourrissant leurs jeunes parcourent regulierement jusqu'a 120 km au large, jusqu'au plateau continental et reviennent avec du krill, Etlphazlsia superba. La position des manchots lors des sorties alimentaires est comparee aux anciennes donnees a echelle precise de captures de krill des regions en question. I1 est possible que la p@cheriede krill entre en competition avec les manchots, notamment lorsque les conditions glaciaires permettent a la flottille de p&chede s'approcher de la bordure du plateau continental ou lorsque les manchots s'approvisionnent en aval de la p6cherie. I1 est suggere d'etudier le chevauchement potentiel des secteurs d'alimentation des manchots Adelie et des concentrations exploitables de krill avant que ne soit prise la d6cision de mettre en place de nouveaux sites du CEMP. B ~aCT02~efipa60l.e npeACTaBneHa CBOAKa AaHHbIX no HarYnbHbIM apeanaM nHHrBMHOB Anen~,OnpeAeneHHblM C IlOMOWbH) CnYTHAKOBOrO CJIeKeHMX, H3 CeMH AaneKO paCnOnOXeHHbIX Apyr OT Apyra rHe3AOBbIX KO~OHM&BAOnb BOCTOYHOrO n06epe~bRAHT~~KTHQ~I MelKQy 5S0e.fl. (3e~nR3~Aep6M) 11 175"~.~.(~Ope Pocc~). ~AH~BAH~IAflen~, KopMHBKlHe CBOHX nTeHuOB, PerynXpHO ~06b1~ankiKpHJIX (Euphausia superba) Ha KOHTAHeHTanbHOM ILIeJIb@e, T.e. 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Resumen Este trabajo presenta un resumen de 10s lugares de alimentacion de 10s pingiiinos adelia, determinados mediante el rastreo por satklite de siete colol~iasde reproduccion situadas a gran distancia entre si, a lo largo de la costa este de la Antirtida entre 10s 55"E (Territorio de Enderby) y 175"E (Mar de Ross). Los pingiiinos adelia que alimentaban a sus polluelos hicieron viajes regulares hasta la plataforma continental (aprox. 120 km de la costa), y retornaron con kril, Etiphausia superba. Se hizo una comparacion entre las zonas de alimentacion de 10s pingiiinos y 10s registros l~istoricosde las capturas de kril a escala fina ell las regiones de inter&. La posibilidad de que ocurra una superposicion con la pesqueria de kril aumenta cuando las condiciones del hie10 son tales que permiten un acercamiento de la flota pesquera a1 borde de la plataforma continental, o cuando 10s pingiiinos se alimentan corriente abajo del lugar donde esti operando la pesqueria. Se propone investigar primero la posible superposicion entre las zonas de alimentacion de 10s pingiiinos adelia y las concentraciones explotables de kril, antes de decidir el establecimiento de nuevas localidades del CEMP. Keywords: Adklie, Casey, CEMP, Dumont dfUrville, foraging, krill, Mawson, monitoring, penguin, satellite tracking, Terra Nova Bay, CCAMLR INTRODUCTION undertaken to determine the foraging range of breeding Adelie penguins and to examine the The CCAMLR Ecosystem Monitoring Program temporal and spatial constraints facing them (CEMP) seeks to determine whether the harvest of when it comes to obtaining food for their krill is likely to have an impact on krill predators. offspring. The following presents a synthesis of Although Adelie penguins are being monitored at all tracking data obtained from the above sites a number of sites around Antarctica, a spatial between the 1992/93 and 1995/96 breeding overlap between the foraging areas of these birds seasons, and compares these foraging locations and the areas where krill fishing has taken place with fine-scale catch data on Antarctic krill, in the previous seasons was demonstrated only in Euphat~siaszlpevba, for each of the s~~bareas. the case of Bechervaise Island (67"311S, 62'49'E) near Mawson Station (Kerry et al., 1992, 1995a). The possibility of an overlap between the krill METHODS fishery and the foraging areas of penguins at locations in the Antarctic Peninsula region Locations of the Adelie penguin colonies from (Subarea 48.1) was investigated by Agnew (1992) which tracking was undertaken are shown in based on the time penguins are away from their Figure 1. The numbers of penguins tracked, the colonies and their average swimming speed as numbers of trips and the years over which reported by, for example, Lishman (1985) and tracking took place are provided in Table 1. Trivelpiece et al. (1987). Since then, however, significant competition between the overall The ARGOS satellite Global Positioning penguin population and this krill fishery has been System (GPS) was used to track penguins. The considered unlikely because the preferred fishing method for tracking birds by ARGOS satellite areas are not adjacent to the largest penguin telemetry is given in Kerry et al. (1995a). The colonies (Ichii et al., 1994; Agnew and Phegan, locations of all satellite fixes of ARGOS quality 1 1995). or better (i.e. the geolocation should be within 1 km of the true position; ARGOS, 1996) are We have been tracking Adelie penguins on plotted in Figure 2 for the Mawson and Davis foraging trips by satellite for up to five breeding regions, and in Figure 3a-c for Casey, Dumont seasons at seven sites along the coast of eastern d'urville and Edmonson Point. Foraging Antarctica. Four of the sites are in CCAMLR locations of birds rearing chicks were determined Statistical Division 58.4.2, two in Division 58.4.1 at each site during every season in which tracking and one in Subarea 88.1 (Figure 1). This work was was carried out. In addition, penguins foraging The Foraging Range of AdPlie Penguins Table 1: Number of AdPlie penguins tracked for each location. I Location of Colony I Years Bechervaise Island (Mawson) Scullin Monolith Ufs Island Magnetic Island (Davis) Sl-tirley Island (Casey) Petrel Island (Dumont d'urville) Edmonson Point during incubation were tracked at Bechervaise approximately the position of the continental Island, Magnetic Island and Edmonson Point. No shelf break. Individual tracks of penguins from distinction is made between male and female this colony are reported in Kerry et al. (1995a). At foraging patterns, although differences have been Davis, birds foraging during the incubation demonstrated (Clarke et al., 1995). The position period headed northwards and some reached the data are presented as a cloud of points since the continental slope. purpose of this paper is to show where the birds concentrate to forage rather than to present Penguins foraging for their chicks at the individual foraging trips. Bechervaise Island CEMP site travelled up to 120 km north to northwest from the colony in a The data on krill catches presented in V-shaped area with an angle of approximately Figures 2b and 3a-c were derived from the records 30". Whilst fast-ice was still present they walked submitted by Japan and held in the CCAMLR to the closest edge of a polynya which forms each Data Centre. These data are shown as the sum of year in this region (Kerry et al., 1995a). The all past harvests of krill taken within a grid of location of this polynya may often be identified 0.5" latitude by 1" longitude (approximately from the colony by the presence of 'water sky''. 30 km by 30 km) between 1972 and 1994. They Birds from Ufs Island tracked during the early are taken as indicating the consistent presence of creche period also showed a similar V-shaped harvestable amounts of krill. Details of a foraging area. At Scullin Monolith, to the east of hydroacoustic survey which covers areas close to Mawson, birds tended to move in a northeasterly Casey and Dumont dlUrville in March 1996 are direction, but once out near the shelf break moved presented separately in Nicol et al.