Basin-Scale Coherence in Phenology of Shrimps and Phytoplankton in the North Atlantic Ocean

Fine-Tuning Fisheries The past decade has seen a tremendous increase in our understanding of how climate anomalies affect hydrographic properties in North Atlantic Shelf ecosystems, but less about how these events impact organisms. Koeller et al. (p. 791, see the Perspective by Greene et al.) measured the egg incubation and hatching times of an important fisheries resource, the pink North Atlantic shrimp, at a variety of locations and compared them to the timing of the local spring phytoplankton bloom. Shrimp reproduction was determined locally by bottom-water temperatures and was not directly coupled with the spring bloom. While the local bottom temperatures and bloom timing are well-matched in general, and match egg hatching to food availability, this evolved relationship can be decoupled by interannual variability and climate change. Shrimp reproduction is primed by bottom temperature and not directly by cues from the spring phytoplankton bloom. Climate change could lead to mismatches between the reproductive cycles of marine organisms and their planktonic food. We tested this hypothesis by comparing shrimp (Pandalus borealis) egg hatching times and satellite-derived phytoplankton bloom dynamics throughout the North Atlantic. At large spatial and long temporal (10 years or longer) scales, hatching was correlated with the timing of the spring phytoplankton bloom. Annual egg development and hatching times were determined locally by bottom water temperature. We conclude that different populations of P. borealis have adapted to local temperatures and bloom timing, matching egg hatching to food availability under average conditions. This strategy is vulnerable to interannual oceanographic variability and long-term climatic changes.