Tuesday, August 24, 2010

Let's hear it for the boys

Someone once asked me why I’m studying male snow crab reproduction. My first response was, “Why not?” But the real answer is Joel Webb is monopolizing all the female crabs! No, that’s not the real answer, but it’s true. He is.

me with one of Joel's females... sigh...

The real answer is snow crab is a male-only fishery with a minimum size limit (the females aren’t targeted and, if caught, get thrown back). Removing large males can negatively affect a population because it may be giving smaller males more opportunities to mate. The idea is, because snow crabs terminally molt at different sizes, the males who are smaller than the fishery size limit will never be harvested, and therefore will be around for more reproductive seasons than the larger commercially targeted guys. If maturing smaller is a genetic trait, the smaller males’ offspring may tend towards maturing smaller too. It’s the classic case of shrinkage…

Oh, wait, that’s not what that means? Oh, well…

ANYWAY, it’s necessary to understand the role males play in reproduction, not just the females, when trying to estimate population size for management. The eastern Bering Sea stock was declared overfished by NMFS in 1999, and while the fishery continues, the stock is still in a rebuilding phase.

snow crab estimated biomass and landings showing the decline in 1999

That’s right guys, you’re important too.

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