Sugar kelp and triploid oyster production to promote sustainable integrated multitrophic aquaculture

Project Overview

Project Type: Farmer
Funds awarded in 2013: $14,970.00
Projected End Date: 12/31/2013
Region: Northeast
State: Massachusetts
Project Leader:
Dr. Daniel Ward
Ward Aquafarms, LLC

Annual Reports


  • Animals: shellfish


  • Animal Production: animal protection and health
  • Crop Production: multiple cropping, nutrient cycling
  • Education and Training: demonstration, extension, on-farm/ranch research
  • Farm Business Management: whole farm planning, budgets/cost and returns, agricultural finance
  • Natural Resources/Environment: habitat enhancement
  • Production Systems: holistic management, integrated crop and livestock systems
  • Sustainable Communities: community services, sustainability measures

    Proposal summary:

    There are no marine aquaculture farms in Massachusetts, and very few farms in the country that culture multiple species at different trophic levels on the same farm, despite the known synergistic benefits to both the farm and the environment. The concept, known as integrated multi-trophic aquaculture (IMTA) presents many benefits to the farmer such as disease reduction, diversification of risk, faster growth rates for all species involved, and sustainable, environmentally friendly food production (Chopin 2006; Neori et al. 2007). In this project we will add sugar kelp (Laminaria saccharina) culture to our existing oyster farm to 1) take advantage of the known culture technique, 2) utilize an established market with great demand for this product, and 3) collaborate with other farmers in northern New England culturing the macroalgae who are very willing to assist in establishing new farms. We will also investigate the advantages of growing triploid oysters (Crassostrea virginica) concurrent with the sugar kelp to increase yield and improve growth year-round, while bringing a consistent product to market (Nell 2002). By incorporating sugar kelp and triploid oysters to the existing farm we will increase economic viability, while diversifying risk and increasing nitrogen removal from the ecosystem. At the conclusion of this project, the results will be disseminated through conference presentations and workshops to other farmers in the region, so that others can build upon what is learned to increase revenue and expand aquaculture production throughout New England. The Cape Cod Cooperative Extension (CCCE) will be assisting with the outreach component of this project. Dan Ward will present the results at farmer workshops held by CCCE, and MAA (MA Aquaculture Association), and he will put together the results into an information sheet which can be posted on the CCCE and Woods Hole Sea Grant websites for farmers to access. Dan will also present the results at the Northeast Aquaculture Conference and Expo (NACE), which will be held in December 2014.

    Project objectives from proposal:

    Objective 1. Investigate sugar kelp culture in conjunction with shellfish operations in order to increase farmer income and remove nutrients from coastal waters.

    Macroalgae culture helps is a very effective method of removing nutrients from coastal waters, while providing additional products for farmers to grow. The culture technique has been optimized by Ocean Approved (Portland, ME), and has proved to be economically viable and produce a high quality food-grade product. Seaweed culture has never been attempted on a commercial scale in Massachusetts, and through this project we seek to evaluate the culture method and economic viability of sugar kelp culture in the coastal waters of Falmouth, MA.

    Sugar kelp culture:
    In Buzzard’s Bay there are many naturally occurring sugar kelp beds and they start to produce spores annually in the late fall, dependent on when water temperatures fall below 50°F. Paul Dobbin’s of Oceans Approved, ME (unfunded partner in this project) has demonstrated when a plant is nearing maturity, and will assist with assessing maturity as the fall progresses. I (Dan Ward) will be diving throughout the fall to assess maturity, and I will be sending pictures and samples to Paul. When the timing is correct, the plants will be collected from wild stocks, and transported to the kelp nursery in my garage. Paul has demonstrated the entire process outlined below, and the results are excellent, though the process itself is remarkably simple.

    The process for seeding the lines is as follows:

    Once the mature plants have been collected, the spores can be scraped off and put into a static seawater bath. After performing density counts, the spores will be adjusted to a density of 7-10,000 spores per milliliter. Five, 15 ¼” x 2” PVC pipes will be constructed, and will be tightly wrapped with 1,000’ of 1mm nylon string. Additionally, five, 16” x 4” PVC pipes will also be constructed, sealed on one end and filled with the spore-seawater mixture. One of the 2”string-wrapped PVC pipes will be put into each one of the 4” PVC pipes filled with the kelp spores, and the 4” pipe will be inserted into a chilled seawater bath at 52°F overnight. The next day after the spores have all attached, the 2” PVC pipes will be removed and put into 5 separate, 20 gal aquaria with air and chilled seawater to each tank. The tanks will be maintained at 50°F for 30 days, with appropriate sunlight-equivalent UV lighting 12” overhead. At the conclusion of 30 days, the kelp will be sufficiently attached and the lines will be ready to be moved to the ocean for growout.

    There will be a total of five, 1,000’ lines installed at the current Megansett Harbor oyster farm. The lines will be installed starting at the northwest corner, leading from north to south, spaced 25’ apart. Each line will have a 3-point mooring at each end, constructed of 3, 12” helical anchors, connected to a bridal, which is then attached to rope leading to a marker buoy on the surface. Connecting the two moorings (spaced 1,000’ apart) will be 1,000’ of 7/16” rope connected at a depth of 7’ with a shackle on either end (the head rope or longline on which the kelp will grow). Every 100’ there will be a stabilizer bar made of 7’ of ¾” PVC with a buoy at one end, and a 5lb. weight on the other, which will be connected to the longline to ensure no twisting of the line, and that no part of the line will rise or sink below the desired 7’ depth. The floatation and weight will be monitored bi-monthly throughout the winter as the kelp continues to grow.

    Following the 30 day nursery period, the 1mm nylon string will be brought to the site, and wrapped around the 1,000’ 7/16” rope and connected with cable ties every 25’. The line will then be sunk to 7’ (as described above), and checked bi-monthly and adjusted as necessary to remain at 7’ depth. Harvesting will most likely start in late March, though it could be as late as early April, dependent on water temperatures. I will harvest the largest plants weekly, leaving the smaller plants underneath to continue growing, with all of the harvesting concluded by early June. The harvesting will be conducted by manually bringing the rope to the surface and cutting off plants into the boat, then transporting the mature kelp weekly to Ocean Approved in Maine.

    Objective 2. Determine biological and economic viability of raising triploid eastern oysters on a subtidal shellfish lease in Falmouth, MA.

    Oyster growers in the Chesapeake Bay area continue to plant over 91% of their oysters as triploids, while in the Northeast, farmers continue to plant primarily diploid oysters (Murray and Hudson, 2011). Dependent on site conditions, triploid oysters have been shown to grow faster and have better market acceptance throughout the year. We will plant triploid and diploid oysters of two different strains, from two different hatcheries, and compare survival and growth in conjunction with water quality data collected throughout the growing season. Therefore, at the conclusion we will be able to make recommendations to other farmers throughout the Northeast as to whether they should grow triploid oysters, which may increase income, reduce culture time and increase overall economic viability of shellfish farming in the region.

    Triploid oyster culture:
    Four different strains of triploid oysters will be purchased:

    Muscongus Bay Aquaculture, Bremen ME
    100,000 1.5mm NEH x Flowers Triploid
    100,000 1.5mm NEH x Flowers Diploid (shipped by mid-May 2013)

    The NEH disease resistant strain developed by Rutgers is resistant to both Dermo and MSX, though has not been shown to have above-average growth characteristics (Dr. Gomez-Chiarri, per comm.) The Flowers strain has been shown to be resistant to Dermo and MSX as well as minimally resistant to JOD. This line has been developed from a Long Island Sound stock initially, and is ideally adapted to southern New England waters. The NEH broodstock tetraploidy will be produced according to the “4C’s” proprietary method of tetraploidy, which will then be crossed with diploid Flowers broodstock to produce triploid NEHxFlowers. Diploid strains will be produced from normal Flowers and NEH diploid stock.

    Mook Aquaculture, Damariscotta ME
    100,000 1.6mm Damariscotta x VIMS Triploid
    100,000 1.6mm Damariscotta x VIMS Diploid (shipped early to mid-May)

    The Damariscotta line has been selected over many years by the Mook Aquaculture growers. This will be crossed by a VIMS disease resistant stock, which has also been shown to possess excellent growth characteristics. Tetraploidy in the VIMS broodstock will be induced through the VIMS method, which will then be crossed with diploid Damariscotta broodstock in order to produce Damariscotta x VIMS triploids. Diploid strains will be produced from normal Damariscotta and VIMS diploid stock.

    The 100,000 oyster of each strain will be equally distributed as soon as they arrive in May, and the seed will all be held in the manner in which typical small seed is grown in the subtidal farms; 0.75mm spat bags at initial densities of 100mls per bag. The oysters will be checked and the bags cleaned every other day, and the oysters will be graded bi-monthly in order to move up to 1.5mm spat bags, and finally 4mm ADPI bags for grow out.

    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.