Maine Family Sea Farm Cooperative Hatchery

Progress report for FNE21-972

Project Type: Farmer
Funds awarded in 2021: $14,795.00
Projected End Date: 10/31/2024
Grant Recipient: Butterfield Shellfish
Region: Northeast
State: Maine
Project Leader:
Keith Butterfield
Butterfield Shellfish
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Project Information

Project Objectives:

The question we will answer is whether a small scale hatchery is a viable solution to concerns regarding access to oyster seed. This project will report on the three elements of success for a small scale hatchery to improve the durability of farmer's profits. The results will be turned into a 10 page/slide brochure, and powerpoint presentation for distribution. 

1) design and construction

2) operation

3) feasibility

The first objective is to build the hatchery, and document blueprints, materials list and methodology. The second objective will be to successfully spawn and settle at least one million oysters per year. This project will provide a readable, twelve step guide for farmers, assessing the basics of hatchery operations, with reference to the existing and advanced methodology. The third, and most important objective is to assess feasibility, created from the three financial statements. By assessing the financial and technical viability, this project will remove the largest of unknowns for interested farmers. Although the results of this project will be relevant to all oyster farmers, it will be cold water aquaculturists that are the primary beneficiaries. The project's results will be aggregated into a 10 page brochure.


The Department of Marine resources has mandated that any seed purchased outside of an individual's health zone must be from a licensed hatchery in the state of Maine, or the individual must receive a special exemption. There are two viable hatcheries that supply oyster seed to the entire state; in recent years, both have experienced highly variable spawning rates. The volatility has resulted in farmers taking inventory of their seed late into the season. This poses a threat to the livelihood of farmers in the Northeast, because their oysters require the growth attained during the Summer months. Far more severe than extending the time to market, is the greater threat of mortality. If an oyster cannot store an adequate amount of glycogen reserves, it will not survive the Winter; smaller and thinner oysters have significantly increased odds of mortality.

All four constituents of the Maine Family Sea Farm cooperative have suffered revenue losses due to delayed seed delivery. Vertically integrating to stabilize inventory will have an immediate positive impact on these four farms; if the small scale hatchery model is proven to be valuable, then other farms and cooperatives will seek to recreate our success. There are approximately 100 oyster farms in the state of Maine, and all of them require a reliable source of seed. This project is especially applicable to cold water oyster farmers, as they have a shortened growing season and face the annual challenge of overwintering. There are several hundred cold water oyster farms in the country that would be interested in the results of this project. A commercial hatchery costs between one and five million dollars, and requires at least three full time employees to operate. Small and medium farms lack the capital to invest in a standard hatchery; this project is to investigate the viability of a small scale hatchery, requiring less than one hundred thousand dollars and two part-time operators. 

This project will foremost be an exploration of the viability and return on investment of a small scale hatchery. More than benefitting the individual farm, diversification in seed suppliers improves industry robustness. By empowering oyster farmers to take vertical control of their inventory, they will have more predictable revenue streams. Should either (or both) licensed hatchery suffer a catastrophic failure, the entire industry would be threatened. This project will lead to improved productivity, and sustained long term profitability for cold water oyster farmers.

The need for consistent seed suppliers has grown in recent years, in parallel to the advent of many new farmers. This model seeks to outsource some of the responsibility of spawning to the farmer, in their respective health zone. This project does not seek to disrupt the current hatcheries; many small scale and local hatcheries would act as a complimentary addition to existing seed purchases, as well as a hedge against spawning failure. The two licensed hatcheries in Maine have cited biosecurity and PH issues once every two to four years. Either threat is cause for serious concern, and is difficult to overcome; both of these causes of mortality are intrinsically linked to the hatchery's body of water.

It should not go without mention that there is a company planning to open their own hatchery in Casco Bay. Unfortunately, Running Tide will indefinitely not be selling seed for the next couple years. The company has faced severe setbacks, and has not disclosed when, and if they are still planning to supply seed to other farmers. If Running Tide starts selling in the future, they will relieve some of the pressure on the two existing hatcheries. However, they will not provide the widespread diversification and individual empowerment the proposed model seeks to deliver to farmers.


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  • Dr. Dale Leavitt - Technical Advisor
  • Andy Stevenson - Technical Advisor (Educator)


Materials and methods:

Project work will begin in June 2022.


The Materials and Methods of this project have been discussed with the project's technical advisors, and are broadly outlined. Construction and operation of the hatchery are far more tedious endeavors than shown below.

  1. Design and Construction of a small hatchery
  2. Operating a small hatchery, tracking growth rates and Mortality
  3. Recording financials, publishing the brochure

Design and Construction

In order to construct the hatchery, initial sketches and a materials list will be confirmed with this project's technical advisors. Keith Butterfield will be responsible for acquiring the necessary materials and cabin boat. The company Green Marine will insulate the boat chosen to house the hatchery. Once the cabin has been cleared, Keith Butterfield will install a water intake system in the boat's stern, and work benches immediately beside it. There will be a heating and treatment system attached to the intake; installation of the uv and particle filters will require more assistance by Green Marine. The work benches support fiberglass silos to hold young oyster spat. The silos require a drainage mechanism, and 1/2" plastic tubing feeding in treated water. The final steps in constructing the hatchery are to install two 2' x 2' shallow holding tanks for mature oysters. When water can be seen to be pulled from the ocean, treated by a uv and particle filter, warmed by a hot water heater, flow through the shallow holding tanks and into the silos, then drain off the top of the silos and out of the boat, the hatchery will be ready for operation.

Excel spreadsheets will be used to record the results of this project. Prospective farmers will be interested in growth and mortality of the local spawn, which can be verified through data collected. All scientific data will be derived from Simple Random Sampling, and will be subject to a NOVA assessment to control for variability. Feasibility will be assessed by three financial statements, once viability has been confirmed.

Operations and Recording Growth

Hatchery spawning and settling begins by selecting oysters from each constituent's farm, and decontaminating them with a wire brush and freshwater. The cooperative's technical advisors will assist in the first spawning process, and will answer outstanding questions for the remainder of this project. After 72 hours of being submerged in the first shallow holding tank, the oysters will be ready to spawn. By adjusting temperature and salinity to 68 degrees Farenheit and 25 ppt respectively, the male oysters will begin to release their sperm, fertilizing the eggs of the females. After 48 hours, the water containing the newly fertilized eggs will be drained into the second holding tank. This larvae will require 10-14 days before they are ready to settle onto cultch; a microscope will be used to confirm the development of the oyster's "foot," therefore signaling its ability to settle onto a hard substrate. Once detected, a thin layer of oyster shell will be laid on the base of the second shallow holding tank. 

14-17 days after the initial spawn, the settled spat will be transferred to silos. Every week, the oysters will be examined under a microscope with 1-3mm reference lines. The project's technical advisors will supervise the first measurement and a NOVA calculation will be done to determine average size. The oysters will be fed weekly by adding the recommended amount of frozen algae supplied by Mook Sea Farm to the shallow holding pools. Water will be drained and refilled at a constant and gradually increasing rate, that is determined by the size of the oyster spat, and regulated by the intake system. Once the oysters have reached an average size of 3mm they will be transferred to Thomas Henninger's upwellers by emptying the silos and sieving the oysters over a 3mm screen. The seed that does not fall through the screen will be placed into coolers, and carefully transported 2 miles by boat to the upwellers. Any oysters that do not pass through the 3mm sieve will be returned to the silos for further growth.

Thomas Henninger provides a daily cleaning of the oysters by removing any algae collected on the surface and lightly stirring the seed. Every week, Thomas will randomly select a total of 20 oysters from four different bins and record their sizes under a microscope with 2mm reference lines. When the oyster's average size reaches 8mm, they are run through a mechanical sieve, and placed into Hexcyl baskets and Intermas bags to be grown on the constituents' farms. Growth will be recorded every month by measuring a random sample of 50 oysters from at least 5 different areas of each farm. Measurements will be taken from the hinge to the mantle (lengthwise) from 8mm until a market size (at least 2.5"). The participants will include a water displacement method to measure volume of the oysters once they have reached an average length of 16mm. Participants will fill a graduated cylinder with 100ml of water and add a single oyster to the cylinder. Subtracting the final volume with the oyster from the initial volume without it yields the volume of the oyster. Volume is an important measurement as it controls for cup development; greater shell depth equates to improved glycogen reserves and a higher quality product. 

Three overwintering methods will be used to test the health and durability of the locally spawned oyster seed. These methods include sinking the young oysters to the bottom, leaving them to float on the surface and dry storage in a cooler; each approach will receive one third of the outstanding seed. In the Spring, mortality will be recorded for each method separately. The weighted average of those three methods will be used to compare to the coop's seed purchased from a licensed hatchery. By randomly selecting 5% of the total volume of product, and counting the number of dead oysters divided by the total number in the given unit of volume, the total mortality can be extrapolated for each respective overwintering method. There will be an inter-method comparison of the locally spawned seed and the seed from a licensed hatchery separately. After each seed stock's total mortality has been estimated, they will be compared in the excel spreadsheet, and analyzed with the project's technical advisors. Once mortality has been assessed, the year's growth of the local spat will be examined, and compared to industry standards. The process of spawning, upwelling and overwinter oyster spat will be conducted every year for three years; this applies for data collection, and annual examination in the Spring. 

Financials and Deliverables

Starting in January of 2022, Keith Butterfield will collaborate with Crunch Consulting to develop project financial statements. These reports will be parallel, and in addition to, the necessary reporting standards of SARE. All expenditures (including labor) will be tracked in an excel spreadsheet, and entered into a Financial Statement. This process will be done each year for three years. 

All deliverables will be condensed to answer this project's central question, and published in a 10 page brochure by Keith Butterfield. Along with Thomas Henninger, Keith will present the materials at Aquaculture in Shared Waters I, II, and the business development course offered by the Island Institute. Keith will coordinate with Bob Rheault and Dana Morse for widespread outreach.


Participation Summary
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.