An experimental release of roughly 300,000 juvenile king crab that was planned for this summer has been postponed until next year. The release is part of the long-running Alaska King Crab Research, Rehabilitation and Biology Program (AKCRRAB), the aim of which is to test how well hatchery-reared crabs survive in the wild and what factors affect their survival.
This year, researchers had planned to out-stock “upwards of 300,000” juvenile king crab, that had been raised from embryos at the Alutiiq Pride Shellfish Hatchery in Seward.
According to Dr. Robert Foy, director of NOAA’s Alaska Fisheries Science Center Kodiak laboratory, the embryos produced by the broodstock that was collected last year were not healthy enough to proceed with the experimental release. Foy said that the cause is not yet fully clear, but may have been that the ovigerous crab were affected by the warm water event that took place over the past few years.
“When we went out in the spring of last year and again in the fall of last year, we went to get moms – females with clutches – so that means females that are holding embryos that are developing,” said Foy. “In both cases those embryos did not look very healthy.”
The embryos, which were produced by a broodstock collected from Alitak Bay, were sent to a pathobiology lab, where it was found they had microbiotic fouling.
“In simple terms: that kills all the embryos,” said Foy. “What that means is they were not viable for us to raise in the laboratory for our out-stocking program.”
The AKCRRAB program was established in 2009, with one goal: “to enhance depressed king crab populations throughout Alaska.” The objective is to explore culturing wild king crab juveniles for release into the wild. So far, the program has achieved the efficient production of
juvenile crab, conducted research on their behavior and completed a number of small out-planting releases.
“We’ve only out-stocked up to 15,000 juveniles, which is very tiny. Most of them aren’t going to survive, so it’s just a test,” Foy said to the Mirror last year.
This year, the aim was expansion. With the health of the embryos not up to scratch, that step of the project has been postponed.
“We don’t know what it is. It may be due to the extreme warm water event in 2016 and 2017,” said Foy, but reiterated that this is just a theory.
“We weren’t standing there collecting data as it occurred,” he said.
Researchers will spend the next few months collecting a new broodstock, with the aim of conducting a large-scale outstocking of 300,000 juvenile crab next summer.
The results of the program are intended to aid legislators in deciding whether to pursue the rehabilitation of wild king crab stocks through hatchery enhancement. With regards to whether king crab will ever be commercially fished again, Foy said this is not the primary objective of the program.
“Again, this is an experimental release,” he said. “It’s not many crab actually – each mom usually holds about 200,000 eggs.
By: [Kodiak Daily Mirror] by Alistair Gardiner
Reprinted with permission of SeafoodNews.com