We find out a whole lot about crabs in this book. In fact, it could be subtitled Everything You Wanted to Know About Sooks but Were Afraid to Ask. Louise herself becomes an expert on crabs, especially the female ones:
Shedding its shell is a long and painful business for a big Jimmy, but for a she-crab, turning into a sook, it seemed somehow worse. I'd watch them there in the float, knowing once they shed that last time and turned into grown-up lady crabs there was nothing left for them. They hadn't even had a Jimmy make love to them. Poor sooks. They'd never take a trip down the Bay to lay their eggs before they died. The fact that there wasn't much future for the Jimmies once they were packed in eelgrass didn't bother me so much. Males, I thought, always have a chance to live no matter how short their lives, but females, ordinary, ungifted ones, just get soft and die. (15.36)
OK, so it's pretty clear that Louise sees herself in these crabs. They grow up and then get caught and turned into crab stew. Not fun. These crabs never even get the chance to get it on or have little crab babies—they're just lonely and sad, and then they die. This is pretty much the life that Louise sees for herself at this point.
Unlike these crabs, though, Louise has a choice: she can leave Rass Island and make a new life for herself—she doesn't have to get soft and die. There's no need for Louise to resign herself to her fate. If those lady crabs could talk, we think they'd tell Louise to hightail it out of there on the next ferry out of town.
After all, anything's better than becoming crab stew.