MEPS 405:255-269 (2010)  -  DOI: https://doi.org/10.3354/meps08513

Spatial association between hotspots of baleen whales and demographic patterns of Antarctic krill Euphausia superba suggests size-dependent predation

Jarrod A. Santora1,2,*, Christian S. Reiss2, Valerie J. Loeb3, Richard R. Veit4

1Farallon Institute for Advanced Ecosystem Research, PO Box 750756, Petaluma, California 94952, USA
2Antarctic Ecosystem Research Division, Southwest Fisheries Science Center, 3333 Torrey Pines Ct., La Jolla, California 92037, USA
3Moss Landing Marine Laboratories, 8272 Moss Landing Road, Moss Landing, California 95039, USA
4Biology Department, College of Staten Island, City University of New York, 2800 Victory Boulevard, Staten Island, New York 10314, USA

ABSTRACT: We examined the spatial association between baleen whales and their principal prey, Antarctic krill Euphausia superba near the South Shetland Islands (Antarctic Peninsula) using data collected by the US Antarctic Marine Living Resources (AMLR) program during January surveys from 2003 through 2007. Whale distributions were determined using ship-based visual surveys, while data on krill distribution, abundance, and demographic characteristics were derived from net hauls. Approximately 25000 km of transects and 500 net hauls were sampled over 5 yr. We defined hotspots based on statistical criteria to describe persistent areas of occurrence of both whales and krill. Hotspots were identified, and whales and krill length-maturity classes exhibited distinct spatial segregation in their distribution patterns. We found that baleen whales aggregated to krill hotspots that differed in size structure. Humpback whales Megaptera novaeangliae were associated with small (<35 mm) juvenile krill in Bransfield Strait, whereas fin whales Balaenoptera physalus were associated with large (>45 mm) mature krill located offshore. Overlapping these size-dependent krill distributions, Antarctic minke whales B. bonaerensis were associated with intermediate sized krill (35–44 mm). The correlation among different whale species and krill swarms of differing size composition presents an intriguing pattern that deserves further study.


KEY WORDS: Antarctica · Euphausia superba · Krill · Fin whale · Humpback whale · Minke whale · Spatial association · Hotspot


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Cite this article as: Santora JA, Reiss CS, Loeb VJ, Veit RR (2010) Spatial association between hotspots of baleen whales and demographic patterns of Antarctic krill Euphausia superba suggests size-dependent predation. Mar Ecol Prog Ser 405:255-269. https://doi.org/10.3354/meps08513

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