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North Atlantic right whalesEubalaena glacialishave 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 werePseudocalanuscomplex,Calanus finmarchicus, andCentropagesspp. during the winter/spring seasons. The succession of these 3 dominant taxa—Centropagesspp. toPseudocalanuscomplex (day of the year [DOY] mean ± SD: 34 ± 3) toC. 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:Pseudocalanuscomplex andCentropagesspp. aggregations whenCentropagesspp. dominated the bay-wide zooplankton community;Pseudocalanuscomplex patches andC. finmarchicuspatches whenPseudocalanusdominated; and primarilyC. finmarchicuscopepodite stage CIV and CV aggregations when CIII dominated bay-wide abundances. Over the time series, we found thatCentropagesspp. abundance increased andC. finmarchicusdecreased 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.
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The North Atlantic Ecosystem, from Plankton to Whales
Compared with terrestrial ecosystems, marine ecosystems have a higher proportion of heterotrophic biomass. Building from this observation, we define the North Atlantic biome as the region where the large, lipid-rich copepod Calanus finmarchicus is the dominant mesozooplankton species. This species is superbly adapted to take advantage of the intense pulse of productivity associated with the North Atlantic spring bloom. Most of the characteristic North Atlantic species, including cod, herring, and right whales, rely on C. finmarchicus either directly or indirectly. The notion of a biome rests inherently on an assumption of stability, yet conditions in the North Atlantic are anything but stable. Humans have reduced the abundance of many fish and whales (though some recovery is underway). Humans are also introducing physical and chemical trends associated with global climate change. Thus, the future of the North Atlantic depends on the biome's newest species, Homo sapiens.
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- Award ID(s):
- 1851866
- PAR ID:
- 10141610
- Date Published:
- Journal Name:
- Annual Review of Marine Science
- Volume:
- 12
- Issue:
- 1
- ISSN:
- 1941-1405
- Page Range / eLocation ID:
- 339 to 359
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1146/annurev-marine-010419-010752
