Friday, August 24, 2012


The fishery for opies this past year had some exciting news: the stock was declared rebuilt and the quota was increased by 64% for the 2011-12 season. But, in the joy of the fishery we had some troubling news: FIVE boats were caught with females in their possession in June. That = no good.

How did 5 boats all accidentally bring home the ladies? Some are blaming it on the timing of the sea ice retreat this year: there was heavy sea ice for much of the season, so instead of finishing the season around March or April, it pushed the ending to June 15th. What does that have to do with catching female snow crabs? Well, the extension of the season may have pushed into the timing when primiparous or multiparous females have released their clutches and are ready to mate again, putting them in the vicinity of the commercially targeted males. That urge to mate, coupled with poor sorting to "pay close attention to crustacean gender distinctions", may have lead to the five violations.

females (top) have a wide abdominal flap to hold egg clutches
while males (bottom) have a skinny flap to protect their gonopods

Hmm. Here's some food for thought:

The legal size limit for male snow crabs is 78 mm carapace width, although the commercially targeted males tend to be at least 102 mm carapace width.

Female snow crabs are so small compared to males (remember how tiny the gal looked in this video and this video?) and in the 2011 summer survey looked to only reach max carapace widths between 70 - 75 mm.

Perhaps if they were opilio-bairdi hybrids the females could reach the legal size limit (see the size disparity of female snow crabs and Tanner crabs here), but the fact remains that they're still female.

Poor sorting for gender aside, keeping female opies may indicate poor sorting for size as well.

Size distribution of female snow crabs (top panel) and
female Tanner crabs (bottom panel) from the
draft of the 2011 summer trawl survey report

There's a lot of hard work and effort on those boats to bring delicious crab back to land (and to our dinner plates), and the conditions do not make for a nice work environment. I'd like to gives the guys the benefit of the doubt that the retention of females on 5 boats was a simple, rushed error, and I hope, for the health of the fishery, it was a once fivce in a blue moon mistake.

2011 Bering Sea Report Draft:
Chilton, E. A., C. E. Armistead, and R. J. Foy. 2011. The 2011 Eastern Bering Sea Continental Shelf Bottom Trawl Survey: Results for Commercial Crab Species. NOAA Tech Memo NMFS-AFSC.

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