Young hatchery lobsters won’t be tailed Project chief says critters’ mobility ‘fouls’ project

STONINGTON – There are about 40,000 additional lobsters in the waters of eastern Penobscot Bay thanks to the efforts of the Zone C lobster hatchery project.

But no one knows exactly where they are. The young lobsters, it seems, didn’t stay where researchers put them.

During its first year in operation, the hatchery raised more than 39,000 juvenile lobsters until they were about 2 weeks old, at which time they are considered to be at Stage IV in their development. The young lobsters were then distributed in eight of the nine districts in Zone C, the last batch being released at the end of September. Zone C includes the area between Cape Rosier in Brooksville and Jericho Bay out to Matinicus Island.

“It was a pretty good shake-down year,” said Ted Ames, who has managed the hatchery project during construction and operation.

But, Ames said, one of the key elements of the project – tracking the hatchery-raised young lobsters’ survival rate in the wild – will have to wait, at least, until next year.

“What we found is that Stage IV lobsters don’t hang around. They are much more mobile critters than we thought,” Ames said.

“That doesn’t mean that they haven’t survived; it means that they aren’t truly benthic yet. They don’t stay on the bottom; they go back up into the water column again and continue to move around. It may mean that they are better at selecting a habitat than we are.”

The mobility of the juvenile lobsters “certainly fouls up” the study to determine how effective a hatchery can be, Ames said. A joint effort between local lobstermen and the Penobscot East Resource Center, a Stonington-based nonprofit group working to support community fisheries Downeast, the hatchery project was designed to determine if hatchery raised lobsters can survive to maturity and if stocking those lobsters can help to replenish depleted lobster grounds.

The plan is to use divers and genetic tagging methods to identify the hatchery-raised lobsters until they are large enough to be physically tagged.

There have been no previous studies to determine the impact of stocking lobsters, and long-term monitoring of the hatchery-reared lobsters would go a long way to determining if stocking is effective, he said.

The key is to track the lobsters at specific locations from the time they are distributed to the time they reach maturity and enter the fishery, a period of about seven years, and to determine how many survive.

“If that can’t be documented, then it’s all speculation,” Ames said.

On the other hand, if the project can show that hatchery raised lobsters can survive in the wild and can be strategically stocked to rebuild a depleted population in a specific area, that would be a valuable tool for the fishery, he said.

Preliminary research has indicated that a slightly older lobster may be less mobile and easier to monitor. It may be necessary to restructure the project to raise an older crop of lobsters in the future, he said.

“We may have to try some different strategies,” he said.

Initial research by Rick Wahle, a senior research scientist at the Bigleow Laboratory for Ocean Sciences in Boothbay Harbor, indicated that Stage V lobsters are less likely to wander after they are released. Wahle took some of the hatchery’s lobsters and raised them to Stage V, or until they were about 1 month old. He then released them at hatchery distribution sites.

“The preliminary study showed that Stage V remain where you put them, more so than Stage IV,” Ames said.

Dr. Brian Beal at the University of Maine at Machias, who developed the hatchery method, has had some success in raising older lobsters in “lobster condos,” small containers that can be suspended offshore. That method is very labor intensive, Ames said, and he has developed a plan to adapt the hatchery equipment to allow him to raise the older lobsters at the hatchery. He is currently seeking grants to fund those alterations, which could be made by next spring. He added that it might not be possible to have it all ready by the next season, in which case the hatchery will continue to raise Stage IV.

Ames is researching alternative stocking methods that might make it easier to keep track of the younger lobsters. Preparations for the next season likely will begin early next spring, whichever aged lobsters they will be raising. The rearing process, which also includes raising algae to feed the brine shrimp which are fed to the lobsters, would begin sometime in May or early June when lobster fishermen begin catching the egg-bearing female lobsters.