Showing posts with label crab molt. Show all posts
Showing posts with label crab molt. Show all posts

Monday, November 2, 2009

A little bit of a late bloomer...


The Marine Exhibit is now closed (except for special Holiday weekends), but exciting things are still happening in the salty water. This Dungeness crab (Cancer magister) was releasing her eggs on Sunday afternoon. Usually these crabs lay eggs between spring and fall so this one is a little late.

Male dungeness crabs only will mate with females that have recently molted, the female will keep the sperm until her eggs are fully developed. After the female releases the eggs they will go through a series of free floating planktonic stages, molting, changing and growing for up to a year, they then settle to the bottom as little crabs and begin their rough life in the ocean! At about 4 or 5 these species can weigh 2-3lbs and measure 6.5 inches across. If they can escape traps long enough they can also live up to 13 years!

Make sure to come back to the Port Townsend Marine Science Center in the spring to catch some more egg laying action by our resident crabs and other animals!

Thanks for reading!

PTMSC Lab Coordinator,

Valerie

check out the resources:

www.adfg.state.ak.us/pubs/notebook/shellfsh/dungie.php



Friday, September 18, 2009

Crab Molt in Action

Yesterday during homecrew one of our volunteers Betty noticed a red rock crab was molting. Molting is an amazing process that enables a crab to grow larger. The molting crab leaves behind an exact copy of it's itself including the eyes gills and even the stomach lining. To molt the crab backs out through a split along the rear edge of its carapace (the large flat surface on it's back). Once out of it's old 'shell' the crab's body is very soft and it puffs up with water increasing it's size.
Below are pictures showing the molting process:

The split at the back of the carapace has just begun.















A little farther along.






























The crab now has its legs out.















One claw has come out.





























Almost there. . .




































It is finally free! The legs were so soft at this point, they were buckling under the weight of the body!