Duane Stevenson and James Orr are research fisheries biologists at the National Marine Fisheries Service (NMFS) Alaska Fisheries Science Center's Resource Assessment and Conservation Engineering (RACE) Division in Seattle, Washington.  Their research interests include the taxonomy and systematics of many groups of fishes.  In addition to published research, they have worked extensively within both the Alaska Fisheries Science Center groundfish program and the North Pacific Groundfish Observer Program to provide training and produce field guides to several groups of Alaska fishes and invertebrates.   Gerald Hoff is also a research fisheries biologist at the NMFS Alaska Fisheries Science Center's RACE Division in Seattle.  His research focuses on the biology and ecology of noncommercial deepwater fish species in the North Pacific.  He has done extensive work on the ecology and reproduction of skates in Alaska with an emphasis on conservation of their marine habitats.   John McEachran is a professor in the Department of Wildlife and Fisheries Sciences at Texas A&M University in College Station, Texas.  His research concerns the systematics and biogeography of skates and rays, and species diversity and biogeography of fishes of the central western Atlantic.  He has also made several contributions to the series FAO Species Identification Guide for Fishery Purposes.