Isotopic and genetic evidence for site fidelity to feeding grounds in southern right whales (Eubalaena australis)

VALENZUELA, LUCIANO O; SIRONI, MARIANO; ROWNTREE, VICTORIA; SEGER, JON

Buenos aires

Congreso; IV Reunión Binacional de Ecología, XXIV Reunión Argentina de Ecología, XVII Reunión de la Sociedad de Ecología de Chile; 2010

Ocean warming will certainly affect the migratory patterns of many marine species, but specific changes can be predicted only where behavioural mechanisms guiding migration are understood. Southern right whales show maternally inherited site fidelity to near-shore winter nursery grounds, but exactly where they go to feed remains mysterious. They consume huge quantities of copepods and krill, and their reproductive rates respond to fluctuations in krill abundance linked to El Niño-Southern Oscillation. We show that genetic and isotopic data, analysed together, indicate maternally directed site fidelity to diverse feeding grounds for female right whales calving at Península Valdés. Isotope values from skin samples span a broad range (δ 13C = -23.1 to -17.2 , δ15N = 6.0 to 13.8 ) and overlap with values of krill and copepods from a large geographic range; from waters north of the Polar Front, to the southern Patagonian shelf, to offshore Uruguay. The isotope values of skin samples are more similar than expected among individuals sharing the same mitochondrial haplotype, indicating that whales learn summer feeding locations from their mothers, and that the time scale of culturally inherited site fidelity to feeding grounds is at least several generations.