Habitat modelling of key copepod species in the Northwest Atlantic Ocean based on the Atlantic Zone Monitoring Program
Document Type Article
Fourteen years of data collected by the Atlantic Zone Monitoring Program served to model the habitat of four dominant copepod species (Calanus glacialis, Calanus hyperboreus, Calanus finmarchicus, Paracalanus sp.) on the continental shelf and slope waters in the Northwest Atlantic Ocean. Generalized additive mixed models (GAMMs) were applied to abundance and presence-absence data for C. hyperboreus, C. glacialis and Paracalanus sp. and abundance for C. finmarchicus, to describe the optimal environmental productivity envelopes associated with the occurrence and/or the net productivity of these species. The models for Calanus species considered two main phases of their life cycle: (i) an active population growth phase dominated by early stages that occur primarily in surface layers, and (ii) a dormant phase dominated by overwintering stages generally found in deeper layers. GAMMs identified a marked contrast in environmental envelopes occupied by arctic and temperate species. Our analyses underline the importance of using data representative of all the copepodid developmental stages and occupied habitats in order to accurately model the distribution of Calanus species. The value of our models as tools to understand past events in the Northwest Atlantic or to predict future distributions of the species is also discussed.