It is the first closure of the fishery since the 1989-90 season. Fishery managers made the decision based on a July 8-17 trawl survey of Kachemak Bay that put population estimates for tanner crab below 100,000 legal male crabs.
Managers established 100,000 legal males as the benchmark above which the shellfish can be sustainably harvested.
"Basically, we're seeking that population level where we get the maximum sustainable yield," said Nicki Szarzi, a Fish and Game area biologist.
Unfortunately, the trawl survey put the estimate of legal males at 69,000 for Kachemak Bay, the lowest number since the survey began 12 years ago.
Szarzi said previous surveys suggested that numbers might drop.
"We'd been expecting it," she said. "But we'd been hoping against the odds that (the survey) would be better than we thought."
For the moment, the good news is that there are better numbers of juvenile crabs and comparisons to previous surveys suggest that the younger crabs are surviving from one season to the next, Szarzi said.
For the most part, she added, people abide by the closure, though Fish and Game enforcement officers have contacted some people who still have pots in the water to let them know about the closure.
Szarzi said that people may be cited if they don't get their pots out of the water and release any crabs they may have caught.