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.

Ordination methods indicated that predator size and capture depth accounted for 85.2% of the variation in diet, while classification methods were used to illustrate these relationships. Additionally, the study extended into locations not previously sampled, therefore, knowledge was expanded upon pertaining to the distribution ranges of important prey.1997 International Council for the Exploration of the Sea

Ouellet, P., Fuentes-Yaco, C., Savard, L., Platt, T., Sathyendranath, S., Koeller, P., Orr, D., and Siegstad, H. 2011. Ocean surface characteristics influence recruitment variability of populations of northern shrimp (Pandalus borealis) in the Northwest Atlantic. – ICES Journal of Marine Science, 68: 737–744. Remotely sensed data were used to derive simple ecosystem indicators for four regions of the Northwest Atlantic to test the hypothesis that sea surface temperatures (SSTs) and spring phytoplankton bloom characteristics (initiation, timing, intensity, and duration) have a significant influence on larval survival and recruitment of northern shrimp (Pandalus borealis). For all years (1998–2007) and regions, hatching was after the initiation of the bloom and before or after the bloom reached its maximum intensity. The results suggest that the best survival of larvae is associated with high warming rates of SST following hatching, but in very cold environments, warm temperatures at hatching seem to be important for larval survival. The analyses also indicate that larval survival is supported by an early, long phytoplankton bloom which attains high concentrations of chlorophyll a. The results demonstrate the potential of remotely sensed data for deriving simple population-specific ecosystem indicators for potential use in building operational recruitment models for predicting changes in northern shrimp abundance.

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a b s t r a c tA Canadian demersal survey trawl (Campelen 1800) was used to investigate the differences in trawl geometry and resistance using dynamic simulation, flume tank testing, and full-scale at-sea observations. A dynamic simulation of the trawl was evaluated using DynamiT software. A 1:10 scale model was built and tested in a flume tank at the Fisheries and Marine Institute of Memorial University of Newfoundland (Canada). Full-scale observations of the Campelen 1800 in action were collected during the 2011 fall multi-species survey aboard the research vessel CCGS Teleost. The numerical and physical modelling data were assessed to determine their ability to predict full-scale at sea performance of the Campelen 1800 trawl. The numerical simulation data were also compared against scale model engineering performance under identical conditions. The study demonstrates that the ideal method with which to accurately predict full-scale at-sea performance of bottom trawls or used for designing a trawling system probably does not exist. Therefore, the importance of using two or three complementary tools should be encouraged as an ideal process for designing a trawling system and/or assisting the gear development circle.