COMMERCE
Subscriber Services
Classified Ads
Subscribe
Advertise
NEWS
This Month
Editorial
Letters
F/V Safety
Past Issues
ABOUT US
Contact Us
Latest Issue
Subscribe
History
MORE CONTENT
CFN Archives
Links
Each month exclusively in the PRINT edition of CFN
Along the Coast
Ask the Lobster Doc
Bearin’s
Classifieds
Coming Events
Editorial
Enforcement Report
FISH SAFE
Fleet Additions
Letters
Lobster Market Report
New Boats
News Catch
Quahog Market Report
|
Commercial Fisheries News
Volume 35 Number 2
October 2007
Maine Zone C hatchery tests lobster enhancement
STONINGTON, ME – Nearing the end of its second season of operation, the Zone C Lobster Hatchery here is a collaborative effort, initiated and supported by fishermen, with the Stonington-based Penobscot East Resource Center (PERC) providing operational and staffing support.
By most accounts, the hatchery is succeeding, meeting the goals and expectations of its backers. But with Maine’s lobster resource considered by most to be strong and prolific, why a hatchery?
“We are blessed with a natural lobster population that is in very good shape right now and our first priority is keeping that natural population top drawer,” said PERC Executive Director Robin Alden.
“But we are perilously dependent on lobster,” she continued. “When you have an island like this (Deer Isle) with $34.3 million coming in over the docks and it’s over 80% lobster, this is really the whole economic fabric of our community.
“So in essence, fishermen here said, ‘Let’s try and see if we can make this hatchery work and then, if we ever need it, we’ll know.’”
Goals, expectations
There are two obvious questions for any project like this: Does it work? And how do you define success?
Alden, PERC and hatchery staff, and a 16-member fisherman steering committee have made answering those questions a core component of their master plan.
To answer the second question first, Alden said the initial goals of hatchery organizers and supporters are modest, with PERC committed to the hatchery effort for at least 10 years.
The primary short-term goal, she said, is to learn whether it is feasible to use hatchery-reared lobsters to re-establish or increase lobster population density in locally depleted areas – an evaluation complicated by the fact that it takes about seven years for a lobster to reach legal harvest size.
If hatchery lobsters survive over time in sufficient numbers to have any positive impact on the population in the seeded areas, Alden said this also may indicate that the hatchery could be a form of insurance against potential stock declines in the future or man-made impacts that adversely affect the lobster resource.
What is not a goal, Alden emphasized, is to develop a stock enhancement program that might create a so-called “put-and-take” fishery, as is seen in some recreational fishery enhancement programs.
Monitoring survival
Monitoring and scientifically documenting the results of the lobster seeding effort is an extensive, expensive, and painstaking process, Alden said.
Each year, the hatchery holds a collaborative workshop for fishermen and scientists to design and refine a plan to monitor lobster survival after release.
Elements of the plan include diving both before and after release on settlement sites, as well as on unseeded “control” sites by a team led by Rick Wahle of Bigelow Laboratory for Ocean Sciences in West Boothbay Harbor.
The dive team uses visual and suction sampling to assess lobster populations on the seeded sites vs. the control areas. Lobsters collected from the settlement areas are genetically tested against the genetics of the mother and eggs by David Towle of the Mount Desert Island Biological Laboratory.
The absence of any real mechanism for identifying and tracking hatched lobsters has been a tremendous problem for previous lobster hatchery programs, according to Alden. However, genetic advancements now allow proof-positive identification, she said, and the number of matches will provide an indicator of how many hatchery-reared lobsters have survived, or at least remained, within the release area.
The dive research alone costs between $75,000 and $100,000 annually, with local fishermen donating boat time to transport divers to sites.
Since last summer’s dive sampling could not verify that the hatchery’s Stage IV “super swimmer” lobsters were settling on the release sites, this year’s small crop of larger Stage V lobsters – which drop to the bottom immediately – is being viewed as an important research tool in tracking early stage survival and settlement patterns.
Eggers to Stage IV process
The Zone C hatchery operates seasonally from approximately April until late September. The lobster rearing process begins and continues throughout the summer with fishermen bringing in egg-bearing female lobsters caught in their traps under a special permit from the Maine Department of Marine Resources.
In the hatchery, the egged females are kept in individual tanks until they release their eggs. The larval (Stage I) lobsters are then removed from the brood tanks and grown out in 100-gallon conical tanks, constantly aerated to reduce cannibalism. The female brood lobsters are released and eventually replaced with new stock to keep the genetic pool random and wild.
The Stage I lobsters are grown out to Stage IV size, about 14.6 millimeters or penny size, which takes about two weeks in the hatchery environment. During growout, they are fed a diet of hatchery-brewed algae and brine shrimp to achieve healthy and rapid growth.
The hatchery operators are particularly pleased with the 60%-70% survival rates they are seeing from egg to release. It is much higher, they say, than the rates typically found in traditional hatchery designs.
Once the juvenile lobsters hit Stage IV size, they are ready to be released onto pre-chosen sites throughout all nine districts of Zone C – from Matinicus to Vinalhaven and North Haven, all around Deer Isle and Isle au Haut, and up into Blue Hill Bay.
By late September, the hatchery had made successful releases at all of the zone’s districts, according to hatchery director Ted Ames.
Fishermen, in conjunction with Ames, identified the sites chosen for the releases. Release areas have to provide good juvenile lobster habitat – cobble bottom with baseball- to basketball-sized rocks – and also exhibit a low abundance of young lobsters.
Central to the purpose of the hatchery, this provides the setting for hatchery staff and collaborating scientists to evaluate over time whether it is possible to use hatchery-reared juveniles to restock these locally depleted areas.
Volunteers
Several times throughout the summer, volunteer fishermen transport hatchery staff and the Stage IV lobsters to the settlement sites, where the young lobsters are released onto the bottom through a weighted hose.
During 2006, the hatchery’s first year of operation, about 40,000 juvenile lobsters were released. This year, through mid-August, more than 65,000 Stage IV lobsters had been released, with more releases planned through September.
Additionally, and new this year, the hatchery also has a crop of slightly larger Stage V lobsters to stock.
“The reason we are doing this is that Stage Vs are more likely than Stage IVs to settle immediately on the ocean bottom where we can find them and track their survival to adulthood,” Ames said. “This is a critical step for the work we are doing to determine whether hatcheries can actually enhance the fishery.”
By mid-August, the hatchery had released approximately 3,500 Stage V lobsters and had another 4,000 awaiting release that were being held in specially designed lobster “condos” to keep them from eating each other.
In the hatchery
The Zone C hatchery is housed in a building on the Stonington waterfront donated by the Stonington Lobster Co-op, adjacent to a ready supply of fresh seawater that is pumped in and filtered before use.
The hatchery staff includes Rich Crowley, hatchery manager, and Natalie Banks, hatchery technician, both newly hired this year.
Crowley is a Colby College graduate in environmental science, who previously managed the Mount Desert Oceanarium Lobster Hatchery in Bar Harbor, a privately owned facility.
Initial construction costs of the hatchery itself were about $80,000, Alden said, with $27,000 of that coming from fishermen and communities in Zone C. The rest was provided by PERC and through grant funding.
Annual operating costs for the hatchery – which includes staff, equipment, stock, etc. – ranges between $75,000 and $100,000 and, again, Alden said, fishermen and communities are contributing a share of that.
Designed by Ames, the hatchery is based on methodologies developed by Brian Beal of the University of Maine-Machias and Sam Chapman of Waldoboro.
Algae production
Crucial to the success of the hatchery and to the survival rates being achieved there, Crowley said, is the facility’s algae production process.
Two strains of tropical algae are started in a “clean room” at the hatchery. After a week or so, the algal cultures are transferred to an algae growout room where they mature for an additional six to 10 days in 20-gallon cylindrical tubes filled with filtered seawater and nutrients.
Once mature, the algae are then fed to brine shrimp, a common fish food ordered from aquarium suppliers. The brine shrimp arrive in cyst form and must be decapsulated and allowed to grow out in light-bulb heated, insulated 50-gallon tanks.
Algal cultures are fed to the brine shrimp for about 48 hours. The brine shrimp are, in turn, then fed to the Stage I-Stage IV lobsters, along with a fresh infusion of algae, once they are removed from the brood tanks and placed in the conical growout tanks.
Although, technically, the hatchery could be described as a flow-through system, meaning the water is not recycled or re-used, Crowley said it is more accurately a static water system.
The hatchery’s location allows it to draw raw seawater directly from Stonington harbor for one-time use before it is dumped and replaced.
The 100-gallon lobster-rearing tanks, for example, must be drained, flushed, and cleaned about every 48 hours due to ammonia build-up and then refilled with a new supply of filtered seawater.
This requires a lot of manual movement of the juvenile lobster population. However, technical modifications to the hatchery over the past year or so have actually reduced labor demands to where the facility operates smoothly and efficiently with just the two-person staff.
Incoming water supplies, if being used for algae/brine shrimp production, are pre-heated using a standard pool heater. Temperature-wise, the incoming ocean water is ideal as is for lobster culture use, Crowley said.
Discharge
Effluents from the hatchery are released back into the harbor, untreated, Crowley said, but he added, what goes overboard is essentially a benign, organic product.
Care has been taken to ensure that no harmful or invasive species are released and the only residue that might be found in the hatchery discharge could be trace amounts of bleach from the 10% solution used to clean tanks, according to Crowley.
His faith in the discharge water quality would seem to be supported by the fact that the hatchery holds its Stage V lobsters in barrels right off the co-op dock, a stone’s throw from the outflow drain.
While the hatchery employs a lot of inexpensive, low-tech ingenuity – lobster brood tanks are actually garbage pails, for instance – the overall approach is highly technical, Alden said, and requires rigorous scientific oversight.
Challenges, ownership
Technical challenges notwithstanding, Alden said the hatchery’s biggest ongoing hurdle is “funding, funding, funding.”
Although the state did provide financial support for part of this summer’s dive research, Alden said its clear that securing any significant amount of public funding for the hatchery will be difficult, and that’s OK.
“Part of what PERC is about is providing the umbrella that allows people in the fishing industry and their community members to do things on their own that are beneficial for keeping commercial fishing going for future generations,” she said.
“Very clearly, fishermen have to support the hatchery and, as we go along, will have to do so in greater numbers,” Alden concluded. “But how empowering, because they can say, ‘This is our hatchery.’”
Rick Martin
Back to story list
|
|
Tell us what you think.
