North Atlantic right whale Eubalaena glacialis prey selection in Cape Cod Bay

• Published in: Endangered species research Vol. 51; pp. 15 - 29
• Main Authors: Hudak, CA, Stamieszkin, K, Mayo, CA
• Format: Journal Article
• Language: English
• Published: Oldendorf Inter-Research Science Center 11.05.2023; Inter-Research
• Subjects: Abundance; Aquatic crustaceans; Aquatic mammals; Balaena; Calanus finmarchicus; Centropages; Climatic conditions; Ecological aggregations; Environmental changes; Eubalaena glacialis; Feeding; Food resources; Foraging habitats; Habitats; Marine mammals; Plankton; Predation; Prey; Prey selection; Pseudocalanus; Whales; Zooplankton; Cape Cod Bay
• ISSN: 1863-5407; 1613-4796
• DOI: 10.3354/esr01240

North Atlantic right whales Eubalaena glacialis have been observed feeding in Cape Cod Bay (CCB) for over 8 decades, making CCB the most consistent known feeding habitat under shifting ocean and climate conditions. Determining the composition of the right whales’ prey resource in a stable feeding habitat during a period of environmental change will inform conservation efforts throughout their habitat range. We compared zooplankton sampled in the paths of skim-feeding right whales to the bay-wide zooplankton resource in CCB over 23 yr. The dominant zooplankton taxa in CCB were Pseudocalanus complex, Calanus finmarchicus , and Centropages spp. during the winter/spring seasons. The succession of these 3 dominant taxa— Centropages spp. to Pseudocalanus complex (day of the year [DOY] mean ± SD: 34 ± 3) to C. finmarchicus (DOY 92 ± 3)—has provided right whales with a stable, multi-month food resource in a small portion of their greater North Atlantic habitat. We found that right whales targeted aggregations of non-dominant prey groups: Pseudocalanus complex and Centropages spp. aggregations when Centropages spp. dominated the bay-wide zooplankton community; Pseudocalanus complex patches and C. finmarchicus patches when Pseudocalanus dominated; and primarily C. finmarchicus copepodite stage CIV and CV aggregations when CIII dominated bay-wide abundances. Over the time series, we found that Centropages spp. abundance increased and C. finmarchicus decreased only at the beginning of the season. CCB remains a critical foraging habitat for right whales due to the phenological cycle of their prey and limited inter-annual changes in prey abundance.