Using Trophic Interactions to Better Understand the Ecology of Latent Resources of the Northwest Atlantic Shelf Break Ecosystem

In their seminal paper, Pauly et al. (1998) explicitly described mesopelagic organisms, including both fishes (e.g., families Myctophidae and Sternoptychidae) and krill (order Euphausiacea), as a latent, or unharvested, fisheries resource.  Since that publication there have been a number of developing international fisheries targeting mesopelagic organisms for fish feed and human consumption. In the Northwest Atlantic, mesopelagic organisms appear abundant in continental slope waters and, yet, remain relatively ‘data poor’ compared to other regions.  In this paper we use several long-term data sets (1973-2013) to examine the spatial distribution of mesopelagic fish and krill along the Northwest Atlantic continental shelf break, their interactions with higher trophic levels, and the large-scale environmental drivers structuring both.  Ultimately, mesopelagic fish and krill appear to concentrate along abrupt sub-marine features (i.e., canyons) and are, consequently, being consumed by a variety of commercially important fishes (e.g., Silver Hake, Pollock, Dogfish, and Acadian Rockfish) commonly associated with the shelf break region.    Both mesopelagic fish and krill represent understudied and potentially under-utilized resources.  However, whether their inclusion into regional fisheries would constitute fishing ‘down’ or ‘through’ food webs would depend largely on the intensity of the fishery.