Progress 08/01/19 to 03/31/20

Outputs
Target Audience:The main target audience of this project was aquaculture operations and/or institutions/organizations conducting aquaculture research in the northeastern United States. Many of which the target audience of aquaculture operations in the northeastern United States exist in coastal communities where income is seasonal and the need for more year round jobs will help boost local economies and the wellbeing of the individuals within those coastal communities. However, none of the results from this project have been conveyed to the intended audiences due to Covid-19. Once the threat of Covid-19 has passed, results will be conveyed via presentations at scientific and aquaculture focused conferences in the northeastern United States. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This study provided an opportunity for multiple employees to gain experience in finfish farming. The employees (i.e. not the Primary Investigators) involved in this experiment had an aquaculture research background of primarily shellfish. Their involvement improved their knowledge of finfish aquaculture. Furthermore, they represented the target audience of individuals who have shellfish experience in the northeastern United States, but have limited experience in finfish aquaculture. Thus, they provided an example of how this project could be replicated by other aquaculturists in the northeastern United States. Outside of the individuals involved directly with the experiment, no other individuals have been reached yet. The lack of the information obtained from this study being conveyed to larger audience is due to social distancing restrictions caused by Covid-19. How have the results been disseminated to communities of interest?The results have yet to be disseminated to communities of interest due to social distancing restrictions in placed in regards to Covid-19. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? This study investigated methods to promote small scale finfish aquaculture operations in New England with a focus on promoting year-round revenue for current and future aquaculture operations. The first portion of the study was to investigate the use of a recirculating aquaculture system to raise steelhead trout at a water temperature and feeding rate that optimized growth rates and promoted healthy livestock. The use of the recirculating system was to identify if artificially maintained temperatures can increase biomass production in steelhead trout culturing compared trout pond culturing. The studied also investigate the use of an integrated multi-trophic aquaculture approach (IMTA), which permitted the culturing of different species at different trophic levels. The intention of investigating IMTA was to assess its ability to increase the revenue of small shellfish farms by diversifying the livestock species cultivated while mitigating any negative side effects associated with finfish culture. In New England, growers primarily grow and sell oysters. However, oysters in New England don't grow for about four months a year once water temperatures drop below 10oC. Diversifying the species cultured by aquaculture operations in New England states could provide year round revenue and jobs. During the recirculating aquaculture system phase of the study, average monthly growth rates (grams/day) increased linearly (R2 = 0.9643) at a rate of 1.68% total body weight per day. The Fulton's condition factor (K) of the trout in the recirculating system also increased linearly (R2 = 0.9999). Once the trout from the recirculating aquaculture system were transferred to net pens in December, daily growth rates in weight significantly decreased and the average Fulton's condition factor of the population fluctuated resulting in a minimal decrease from the initial condition factor of the population by the end of the four month net pen experiment. Shellfish in the IMTA portion exhibited no differences in growth rates between the control site and the site adjacent to the net pens. High kelp growth rates were observed adjacent to the net pens, but the high growth may have been due preexisting water environmental conditions in cove were the net pens were located. Overall, the study illustrated the use of a recirculating aquaculture system at optimal temperatures (20oC) results in high gains in biomass and promotes a healthy population of trout for stocking in net pens in winter months when shellfish sales are minimal or nonexistent. However, with no significant growth and increases in health to be expected from the net pen phase, increasing biomass and health beyond that observed in this experiment must be achieved prior to net pen deployment. Thus, an extension in the duration in which the trout are housed in the recirculating aquaculture system would promote a larger more viable market sized trout for sale during winter months when shellfish sales are minimal. Objective I: Investigate optimal multi-trophic production techniques for steelhead trout, eastern oysters, bay scallops and sugar kelp within an integrated system. 1) Major activities completed / experiments conducted Two netpens were installed by Ward Aquafarms into two identical slips at Fiddler's Cove Marina, North Falmouth, MA (Figure 1) in December of 2019. Ward Aquafarms already utilizes two other slips for float storage from October-May, and boat use throughout the year. By placing the net pens adjacent to an existing shellfish farm operation, additional labor costs were be reduced, and integration into standard farm operations was easily established. The two identical surface net pens (4m x 6m x 3m; custom nets from Reidar's Nets, New Bedford, MA), were hung from existing finger piers, utilizing existing flotation and cleats. Figure 1: Cape Cod, Massachusetts. Red inset illustrates the project location at Fiddler's Cove Marina, which is adjacent to Megansett Harbor, where Ward Aquafarms' commercial growout sites are located. Prior to netpen stocking, two different grow-out strategies were implemented. The two different methods of stocking which were evaluated: 1) direct from the hatchery, or 2) pre-growing in recirculating aquaculture system tanks (R.A.S.) (Objective 3). In December of 2019 one net pen was stocked with 1,000 steelhead trout 187.4 grams (SD±34.8) from the recirculating tanks and one netpen was stocked with 1,000 steelhead trout 189.6 grams (SD±34.1) from the hatchery. Once fish were transferred to the netpens, they were fed until satiation over a ten minute period (~0.5% total biomass weight) twice a day. Oysters and bay scallops were stocked at two locations in December 2019: 1) directly adjacent to the trout netpens in the same slip; and 2) in outer Megansett at the farm growout site. In December, 2019, approximately 10,000 oysters (< 100 mm) were be stocked into replicate 5-level, 21 mm monofilament lantern nets at commonly accepted commercial levels (1/3 surface area), and 10,000 bay scallops (< 50 mm) were be stocked into replicate lantern nets, at 20 per ft2. Half of the animals were deployed directly adjacent to the netpens and half of the animals were deployed on the Megansett Harbor growout site (Figure 1). Sugar kelp seed string was purchased from one of the locally available seed string suppliers (Greenwave, CT; Walrus and Carpenter, RI; Cottage City Oysters, MA; Springtide Seaweed ME) in December of 2019. Three, identical 20' lines of sugar kelp were installed adjacent to both the trout netpens, and three identical lines were also installed at the current Megansett Harbor oyster farm. The lines were installed starting at the northwest corner, leading from north to south, spaced 25' apart. The line was then sunk to 7' at all locations. 2) Data collected Total weight and total length measurements were sampled monthly from January through April of 2020 to evaluate growth. All net pens were inspected for holes and mortalities daily, and all mortalities were removed, tallied and disposed of. From January through April of 2020, thirty oysters and thirty bay scallops were sampled from three randomly selected bags or lantern nets monthly. For each organism during each sampling, percent survival and shell height were measured to investigate differences between sites. Sugar kelp lines were checked monthly and adjusted as necessary to remain at 7' depth. In addition to the monthly trout and oyster measurements, all kelp longlines were brought to the surface monthly from initial set (December, 2019) through final harvest (April, 2020) to check for biofouling. During the routine inspection for biofouling, once per month each line was sampled to quantify growth. Three locations were randomly chosen on each of the three lines, and 10 random plants within each 12" section will be measured for total length. When estimating the health of trout, Fulton's condition factor (K) was used (Froese, 2006; Shabani et al., 2018). Fulton's condition factor is a widely accepted metric for estimating the health of fish, such as rainbow trout, and can be an indicator of stress, reproductive status, nutrition and age (Sharma and Bhat, 2015; Dekic et al., 2016; Shabani et al., 2018). The equation used to calculate Fulton's condition factor (K) was: K = ((W)/(L*3))*100 (Froese, 2006; Tasaduq et al., 2011; Sharma and Bhat, 2015; Dekic et al., 2016). The use of Fulton's condition factor (K) allows for health comparisons to other studies involving rainbow trout culturing and health. Percent body weight increase was calculated using the equation: G = ((W2 - W1)/(0.5 x (W1 + W2) x t)) x 100 to allow for comparisons to other steelhead and rainbow trout growth rate studies (Holm et al., 1990; Myrick and Cech, 2005).

Publications