Marine food webs, from primary producers to top predators, can be strongly influenced by climate. Antarctic krill (Euphausia superba) is a key component of the Southern Ocean ecosystem and is the main prey of all baleen whales that feed in Antarctic waters. Krill abundance has been decreasing at the western Antarctic Peninsula (WAP) given climate warming in the region. Here we investigated the effect of variation in krill density on the reproductive success of humpback whales (Megaptera novaeangliae) from Breeding Stock G. Humpback whales’ relative birth rate (RBR), defined as the observed number of calves in relation to non-calves, was obtained from opportunistic surveys carried out on board whale-watching vessels operating near the coast of Ecuador between 2004 and 2010. The relationship between RBR and krill density was significant when considering a lag of 1-year (r2 = 0.9, P = 0.02), and was consistent when considering the RBR balanced by the number of trips (r2 = 0.8, P = 0.02). Therefore, it is recommended that management strategies for krill fisheries consider the effect of climate on the whole Antarctic ecosystem and the potential effect of krill removal on the population recovery of whales.
Elisa Seyboth, Fernando Félix, Mary-Anne Lea, Luciano Dalla Rosa, George M. Watters, Keith Reid, Eduardo R. Secchi. 2021. Influence of krill (Euphausia superba) availability on humpback whale (Megaptera novaeangliae) reproductive rate. Marine Mammal Science, DOI: 10.1111/mms.12805
