Accounting for Detection Probability in Connectivity Patterns for the Northwest Atlantic Coastal Shelf Ecosystems

The Northwest Atlantic Coastal Shelf (NWACS) ecosystem supports production of over 6.5 million MT of finfish and shellfish. This ecosystem is comprised of 10 major sub-ecosystems (5 coastal/estuarine and 5 nearshore) that have their own unique properties as well as physical change of water and fishes.  These sub-ecosystems are experiencing changes attributable to exploitation, eutrophication and climate change.  To effectively manage the fisheries of this ecosystem, we need an understanding of how these systems are connected and how external factors are changing these systems.  To understand the connectivity of these sub-systems, I applied occupancy modeling techniques to summary data sets of multiple fisheries trawl surveys within these systems.  This modeling approach provides information on species-specific patterns in temporary colonization and local extinction rates in surveyed areas.  These models combined with environmental covariates enable the evaluation of environmental factors that affect connectivity.  In addition, occupancy models also are used to estimate detection probability. Simultaneously estimating occupancy/occupancy dynamics parameters (e.g., regional colonization and extinction) and detection probability effectively removes the confounding issues of heterogeneity in surveys and gears used in the sub-systems.