Image: SCOTT C. FRANCE
Once spurned by New England fishermen who regarded them as the prickly pests that devastated valuable lobster populations, sentiments toward green sea urchinshave shifted rather dramatically. Indeed, by the late 1980s sea urchin sales were booming, owing to a large Japanese market for urchin roe, or uni. Meeting that demand, however, has resulted in a significant decline in urchin populations. In fact, last year's population was the smallest since monitoring began in 1983. Now, in an effort to resuscitate the Gulf of Maine's floundering urchin industry, researchers are searching for new ways to cultivate them.
Specifically, University of New Hampshire (UNH) zoologist Larry G. Harris is looking for the most efficient way to mass produce urchins in hatcheries. The creatures must be cultured until they reach a certain size, so Harris is experimenting with different kinds of growing containers. He has also worked with students to develop an urchin growth system. If all goes well the university will have an active urchin aquaculture hatchery by 2002. But there is a second part to the problem. Because storing the urchins is costly and labor intensive, they must be released into the ocean once they reach a certain size. Yet coordinating that outplanting with the natural settlement of wild urchins in the Gulf of Maine means releasing them in June or July, when their predators are most active.
An earlier outplanting would likely disturb the urchins' reproductive cycles, which are linked to their daily exposure to light, or photoperiod. But UNH researchers Charles Walkerand Michael Lesser have succeeded in coaxing the sea urchins into reproducing at different times during the year by manipulating their light exposure. So winter outplantings may not be far off. Walker has also been developing techniques aimed at producing optimal umi. The roe are only marketable during a certain phase in the urchin's reproductive cycle--but by fiddling with the photoperiod, it may be possible to have optimal uni available at all times.