OOA Progress Report for the period 1/01/01 through 12/31/01
Principal Investigator: H. Howell, T. Bradley, L. Buckley, L. Kling, G. Nardi
URI Cod and Haddock (Buckley and Bradley)
Cod and haddock broodstocks were maintained through the period and embryos were provided to a variety of collaborators. This was accomplished despite the loss of most of the cod broodstock and about one-third of the haddock broodstock due to a mechanical failure of the seawater chillers in the summer of 2000. The cod broodstock was replaced in the late fall of 2000 with fish from the Chatham, MA hook fishery. We have experienced difficulty in augmenting the haddock broodstock, although a few fish were collected north of Cape Ann in the spring of 2001. We are expecting good egg production for the 2001-2002 spawning season, and are off to an excellent start. Cod began producing large quantities of good quality egg beginning in December 2001. Haddock spawning should commence again in January or February of 2002.
Last season, cod spawning commenced in December of 2000 and continued into March of 2001 (Figure 1). Haddock spawning began in February of 2001 and ended in May. While the duration of cod spawning was reduced from previous years, egg quality was good. The haddock produced large numbers of eggs during the 2000-2001spawning season, but egg viability was low. The low viability of haddock embryos was most likely due to thermal stress to the spawners over the previous summer. Cod and haddock embryos have been provided to investigators at Great Bay Aquafarms, Univ. of Maine, UNH, Woods Hole Oceanographic Institution, URI, and MIT among others.
We completed several experiments with both cod and haddock during the period. We evaluated the utility of four disinfectants (hydrogen peroxide, PVP Iodine, sodium hypochlorite and a penicillin / streptomycin mixture) for treatment of cod and haddock eggs and have a manuscript in draft. Studies of feeding and metabolic rates of cod and haddock larvae and juveniles were also completed in collaboration with investigators at URI and the NMFS Narragansett Laboratory.
UNH Cod (Howell and Nardi)
Cod juveniles were produced by Great Bay Aquafarms and the Univ. of Maine. Embryos to begin these productions were obtained from the cod broodstock held at the University of Rhode Island (see above). Great Bay Aquafarms produced in excess of 30,000 cod juveniles (about 3g mean weight). Unfortunately, most of these were lost through a deliberate act of sabotage by a former employee. Survivors were transferred to the UNH Coastal Marine Lab. (CML), and this group was supplemented by fish produced at the University of Maine. The fish were maintained at the CML over the next several months.
On 4 June 2001, 204 cod juveniles (mean weight 98g; mean length 21.7cm) were transferred from tanks at the Coastal Marine Laboratory to a small (2.7m3) net pen located under a pier located at the mouth of the Piscataqua River. This was done to acclimate the fish to "field conditions" of tidal currents, natural photoperiod and light intensities, as well as the twine associated with net pens. These were fed 2-3 times a week with a 5mm Corey™ diet. After 8 days in this location, the fish were moved, in insulated, flowing seawater containers, to one the offshore net pens. Here feeding continued on a regular basis, and samples for growth estimates were obtained on two occasions. On the first of these, which occurred 5 weeks after stocking, mean length and weight had increased by about 6cm and 135g, respectively (Figure 2). On September 27th the fish were captured and transferred back to a 75m3 floating net pen located under the same pier mentioned above. The average length and weight upon removal and transfer were 28.6cm and 272.1g, respectively. Thus in a period of about 3.5 months in the offshore net pen, mean length had increased from 21.7 to 28.6cm, an increase of about 32%. Similarly, mean weight increased from about 98g to 272g, and increase of over 177%. In addition to these excellent growth rates, we saw an 86% survival rate, which we consider very good given that the fish were handled at both stocking and removal from the offshore net pen. It is also interesting to note that the cod sampled had copious amounts of skeleton shrimp (Family Caprellidae) in their stomachs. This secondary food source, which lives abundantly on the cage, may have contributed to the golden-orange color the fish exhibited upon removal. Our most recent growth data for this group of fish, taken in mid-December (Figure 2), indicates that the fish are continuing to grow very well. At that time mean length and weight were 34.2cm and 470.5g, respectively, and a few of the fish were over 850g. Our plan is to grow these fish on for use as broodstock.
UNH Halibut (Howell)
The loss of the very large number of cod juveniles at Great Bay Aquafarms (see above) caused us to look for an alternative species to grow in our net pens. In May 2001, a total of 2000 Atlantic halibut were acquired from R&R Finfish Development Ltd. located in Digby, Nova Scotia. The fish were 416 days old and averaged 30g in weight. Following the application for, and receipt of a number of permits, the fish were transferred via truck to the UNH Coastal Marine Lab. (CML). Here the halibut were cultured in 2m diameter tanks supplied with flowing seawater. Initial stocking density was 4.7kg/m2. The fish were fed 5% body weight per day with Shur GainTM halibut feed. Fish were held in the CML until early October (552 days of age), by which time they had reached a mean weight of 100g. Stocking density in the CML tanks at this time was 12.7kg/m2. Approximately 1600 fish were transferred to one of the offshore net pens on October 4th. Initial stocking density of the net pen was 1kg/m2. Because the automated feeding buoy was not yet installed, feeding of the fish was done by divers, 2-3 times per week to satiation. In late October the automated feed buoy was installed, and it has been used since. The fish were sampled for length and weight on a monthly basis (Figures 3 and 4). Growth has been continuous and satisfactory in both the CML and in the offshore net pens, and survival to date has exceeded 98%. In the 5 months spent in the laboratory, mean weight and length increased by approximately 181% and 40%, respectively. This translates to a monthly increase of about 36% for weight and 8% for length. In the two months the fish have been in the offshore net pen, weight has increased by 32% (about 16% per month) and length has increased by 3% (about 1.5% per month). Growth rate differences noted between the laboratory tanks and the net pen are probably not due to differences in the systems and locations, but rather to decreasing temperatures since the fish were moved offshore (Figures 3 and 4).
UNH Haddock (Howell)
In the autumn of 2001, we entered into a research partnership with Heritage Salmon, located in New Brunswick, Canada. Although the company concentrates on the production of Atlantic salmon, they also have also been conducting extensive, and very successful research aimed at producing haddock (Melanogrammus aeglefinus). As an initial stage in our partnership, the company has agreed to provide us with 4000, 100g haddock juveniles that we will raise in one of our offshore net pens. These fish will be moved to the UNH site, using a contracted live hauling vessel, in January 2002. They will be stocked into the net pen and fed using the attached automated feeder. Growth performance will be monitored monthly, and we will raise the fish until they reach market size (approximately 75cm, 3kg).
UM Haddock (Kling)
The Center for Cooperative Aquaculture Research (CCAR), a new facility in Franklin, Maine was readied to receive haddock eggs for the scheduled production trials.
Regrettably, almost no eggs were available from URI (see Buckley and Bradley report above). An attempt to obtain haddock embryos from the Canadian Dept. of Fisheries and Oceans was unsuccessful. For this reason, a request for a no-cost extension of the funding has been submitted, and the work will be done in 2002 when haddock embryos become available.
Reports, Manuscripts and Presentations
Sulikowski, J.A. and W.H. Howell.(In Review). Ionic and hematological changes in the summer flounder (Paralichthys dentatus) associated with their movement from a recirculating system hatchery to an ocean net pen. Aquaculture.
Sulikowski, J.A., W.H. Howell, J.M. Wanat, G.A. Rice, N. Rennels, C. Jones and G. Nardi. Ionic and hematological changes in the summer flounder (Paralichthys dentatus) associated with their movement from a recirculating system to an open ocean net pen. Open Ocean Aquaculture IV. St. Andrews, New Brunswick. June 2001.
King, N.J., G. Nardi and W.H. Howell. Production of Atlantic cod (Gadus morhua) for open ocean aquaculture in New Hampshire. Open Ocean Aquaculture IV. St. Andrews, New Brunswick. June 2001.
Chambers, M.D., W.H. Howell, R. Langan and B. Celikkol. Status of open ocean aquaculture in New Hampshire. Open Ocean Aquaculture IV. St. Andrews, New Brunswick. June 2001.
Chambers, M.D. Operational management of an open ocean farm. Aquaculture 2001. Orlando, FL, January, 2001.
Buckley, L. (In Prep.). Use of egg surface disinfectants in captive spawning Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus).