Unalaska, AK – Colder than average waters have been blamed for late salmon runs and might affect pollock distribution in the Bering Sea. The temperatures might impact crab stocks as well. Alaska Department of Fish & Game manager and researcher Doug Pengilly says that cold water can affect where some types of crab are and potentially how big they can get.

"For the opilio, as you go further north, they tend to mature at a smaller size," he says. "Maybe their growth per molt is less or maybe they're just maturing at a younger instar, but for what ever reason when they molt for maturity at a smaller size, that's as big as they get. So they may not be molting even to legal size."

That means colder waters may impact what can be fished in future years. But Pengilly says scientists don't know much about the biology of crabs their location makes them hard to study. The cold water might affect how long the females hold on to their clutch of eggs, too. He says the science is too rudimentary to influence the determination of total allowable catches (TACs) of different species.

"There's really not enough known there with certainty that you're going to use that to set the TAC. It might give you some background information for looking down the line, but in terms of this year's TAC, it's going to be based on our estimates of what the numbers are."

ADF&G and the National Marine Fisheries Service are trying to learn more about crabs and what factors influence their reproductive potential.

"This is a fishery that's mainly removing males," Pengilly explains. "So what's the effect of removing those males on the reproduction and the productivity of the stock? By removing these males, are we limiting the ability of the females to produce full clutches of eggs?"

Scientists also want to know how reproductive levels vary by age and geography so they can set more accurate catch limits.