As skates become a more common target species for fishermen in the Gulf of Alaska, Gerald Hoff, a scientist with the National Oceanic and Atmospheric Administration, is studying their breeding and nursery habits in Alaska waters.

NOAA manages a directed fishery for skates in the Gulf, and Kodiak began a special directed fishery in state waters in 2003. From January through the first part of September this year, about 2,520 metric tons of skate have been caught in the Gulf. Skates also can be retained as bycatch in the Bering Sea and Aleutian Islands.

Hoff notes that he is starting from scratch in learning about the species’ nursery areas. “Virtually nothing is known about skate nursery grounds in Alaskan waters, yet they are very important for the successful propagation of the greater than 12 species known to exist there,” Hoff said in a NOAA press release. Hoff is a research fisheries biologist at the Alaska Fisheries Science Center in Seattle and also a graduate student at the University of Washington working on his doctorate.

Skates are an elasmobranch related to stingrays and sharks, which in general are large bodied, slow growing and slow to reproduce, making them susceptible to over-harvest. They use distinct nursery grounds, returning annually en masse for long periods of time to mate, bear live young or deposit eggs on the bottom. Understanding the physical and biological characteristics of nursery grounds is important for the successful conservation of the species.

“The goal of my research is to characterize the nursery sites and understand their biological and physical aspects in order to gain a better understanding of skate reproduction, habitat use and nursery area dynamics and vulnerabilities. Successful skate reproduction may depend on secure nursery habitat.”

Hoff focused on two study sites in the southeastern Bering Sea which are nursery grounds for the Alaska skate and the Aleutian skate. The nursery grounds are both relatively small — about 5 square nautical miles.

“I returned to both sites about every 60 days for over a year,” Hoff explained. “I want to determine the annual cycle of egg deposition and the duration of embryo development. I also want to understand more about predation on the developing embryos and newly hatched juveniles. I will spend about the next six months working on analyzing the data collected so far and synthesizing the results with what is known about skate reproduction.”

Skates produce large, tough leathery egg cases that are deposited directly on the ocean floor. The egg cases are left to develop and hatch with little or no involvement of the adult skates. Many beachcombers have encountered skate egg cases worldwide as they often wash up on beaches during storms or after hatching. They are commonly known as mermaids’ purses.

“The two species I am studying are taking about a year to develop inside the egg cases and hatch,” said Hoff. “That is a long time to sit on the ocean floor.”

Although the egg cases are quite tough and protect the developing embryo well, certain snail species are able to drill holes in the egg cases and dine on the large yolk before the embryo has a chance to develop. Also, several large predatory fish species prey on the newly hatched juvenile skates as they emerge from the egg cases.

“Understanding sources of mortality for skates helps scientists determine reproductive success and survival to adulthood which are important conservation aspects,” said Hoff. “Hopes are that by the conclusion of this study we will have a greater understanding of skate nurseries and be able to draw some general conclusions about them.”

Hoff’s skate nursery research is funded by the North Pacific Research Board, the Essential Fish Habitat Division of the Alaska Region of NOAA Fisheries and the Alaska Fisheries Science Center.

Alaska canned salmon is getting a boost from the federal government which is buying nearly 200,000 cases to support the disaster relief efforts associated with Hurricane Katrina and also for use in federal food and nutrition programs. The product is also the topic of its own Web site accessed via a link from the Alaska Seafood Marketing Institute Web site. The canned salmon Web site offers recipes and nutritional information and touts the healthful effects of omega-3 fatty acids found in salmon and other cold-water fish. It can be found through the ASMI Web site at www.alaskaseafood.org/.

Christy Fry has commercial fished in Homer since 1978. She also has designed and built gear for the industry. She currently longlines for halibut and sablefish and gillnets salmon in upper Cook Inlet aboard the F/V Realist.