Physiological, morphometric, and energetic characteristics of Calanus spp. copepods in North Atlantic Right Whale foraging areas

Abstract

Calanus copepods are the prey of North Atlantic right whales (NARW). It is suggested that NARW forage where prey quality per se is higher, however, evidence is limited. I addressed this by characterizing prey quality of Calanus spp. copepods in two NARW foraging areas, including near foraging whales, using morphometrics and energetics. Prey quality was higher in larger animals, i.e., older life stages, Arctic taxa, and diapausers. Most C. finmarchicus were active and lower energy in the Gulf of St. Lawrence (GoSL) in July (5.08 J ind-1, oil sacs 25% full), whereas most were diapausing and higher energy in the Bay of Fundy (BoF) in September (6.90 J ind-1, oil sacs 82% full). Prey quality of C. finmarchicus in the BoF was not lower than years when right whales frequently occurred there. Composition of Calanus patches affects overall prey-field energy density, which should be compared between regions in future studies.