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Chapter 7 - Demersal FishSelection of Target SpeciesThe selection of target species was an iterative processundertaken by the TNC Team Lead and team members.Several factors were considered when selecting target speciesfor this assessment, including: 1) distribution over arange of depths and substrate types, 2) variations in lifehistory, including reproduction and food habits, 3) availabilityand quality of species-specific information, 4)current population status, and 5) distinct ecological roleswithin the Northwest Atlantic. Team members agreed itwas important to develop a more inclusive suite of speciesrepresenting the broad ecological role of demersalfish, rather than focusing more narrowly on those speciesin need of immediate conservation attention. As such,the species analyzed in this assessment range from thosewhose population status is of concern because of significantdepletion relative to historic levels (e.g., cod, halibut,some flounders, and wolffish) to species that are relativelyabundant and show signs of continued improvement(e.g., haddock, redfish, and summer flounder).The 32 species chosen for this assessment were:Gadids• Atlantic cod (Gadus morhua)• Cusk (Brosme brosme)• Haddock (Melanogrammus aeglefinus)• Pollock (Pollachius pollachius)• Red hake (Urophycis chuss)• Silver hake (Merluccius bilinearis)• White hake (Urophycis tenuis)Pleuronectids• American plaice (Hippoglossoides platessoides)• Winter flounder (Pseudopleuronectes americanus)• Witch flounder (Glyptocephalus cynoglossus)• Yellowtail flounder (Pleuronectes ferruginea)Elasmobranchs• Barndoor skate (Dipturus laevis)• Clearnose skate (Raja eglanteria)• Little skate (Raja erinacea)• Rosette skate (Leucoraja garmani)• Spiny dogfish (Squalus acanthias• Thorny skate (Amblyraja radiata)Offshore Wintering Guild• Black sea bass (Centropristis striata)• Northern sea robin (Prionotus carolinus• Scup (Stenotomus chrysops)• Summer flounder (Paralichthys dentatus)Mid-Atlantic Estuarine• Atlantic croaker (Micropogonias undulatus)• Spot (Leiostomus xanthurus)• Weakfish (Cynoscion regalis)Other Species of Interest• Acadian redfish (Sebastes fasciatus)• Atlantic halibut (Hippoglossus hippoglossus)• Atlantic wolffish (Anarhichas lupus)• Golden tilefish (Lopholatilus chamaeleonticeps)• Longhorn sculpin (Myoxocephalus octodecimspinosus)• Monkfish (Lophius americanus)• Ocean pout (Zoarces americanus)• Tautog (Tautoga onitis)Population Status and Importance ofNorthwest Atlantic RegionThe global distribution of the demersal fish species includedin the group is limited to the Atlantic Ocean,with the exception of spiny dogfish which are distributedthroughout many of the world’s oceans. Distributions arelimited primarily to nearshore coastal waters and alongthe Continental Shelf and are controlled by a variety offactors, with water temperature among the most important.Variations in water temperature are especially importantbecause thermal extremes have a greater effecton the distribution of most organisms than mean annualtemperatures. Density and biomass are highest in areaswith broad annual ranges in temperature, and lowest inareas with low annual ranges, although this distributionis probably influenced also by other chemical and physicalproperties of water masses (Cook and Auster 2007).Several species in the group occur in both the Northwestand Northeast Atlantic, with the Northwest Atlantic7-Northwest Atlantic Marine Ecoregional Assessment • Phase 1 Report