OOA Progress Report for the period 1/01/01 through 12/31/01
Principal Investigator: Clifford A. Goudey, Brandy M. Moran
Summary
Our live feed production, larval production, and enhanced grow-out facilities at the MIT Sea Grant Marine Finfish Hatchery were made ready for the 2001 spawning season. Egg batches received from cooperating broodstock facilities were of variable quality. Good to acceptable survivability was experience through rotifer feedings. Mortality rates coincident with the transition to Artemia remain a problem. A water quality problem associated with Boston Harbor conditions caused the loss of or largest and most promising batch of larvae.
At the end of the 2001 production cycle we have less than 200 fish remaining, preventing us from proceeding with the open-ocean phase of the project. Analysis will continue to better understand the causes of mortality, refine our growth model, and evaluate haddock as a candidate for open-ocean commercial production.
Progress on Tasks
Objective 1) Establish intermediate haddock production capabilities at the MIT Sea Grant marine finfish hatchery on Boston Harbor.
Task complete - previously reported
Objective 2) Using eggs supplied by the University of Rhode Island CMER project, culture 15,000 haddock to 200-gram size.
January 2001 - we geared up our hatchery to full production level. Our live feed room was maintaining an average of 80 million rotifers. Our hatching system had been on-line since December 2000 and our biofilters were seeded properly to accept the loading of new larvae. The National Marine Fisheries Service (NMFS) Aquarium in Rhode Island was notified that we were ready to accept haddock eggs. A call was also made to Connor's Bros./Heritage Salmon in New Brunswick, Canada that we needed haddock eggs for our project.
February 2001 - we were notified that the NMFS haddock broodstock was not performing very well, spawning minimal and producing poor batches of eggs. They were not sure if they were going to get any quality and/or quantity of eggs this season.
March 2001 - MIT SG received a call from Connor's that they had approximately 1-liter of excess haddock eggs from their final broodstock spawn that could be transported to Boston for our used in this project.
May 2001 - RI NMFS Aquarium reported a second spawning event of the haddock broodstock. They were not sure how long this second spawning of eggs was going to last.
We received a total of four batches of haddock eggs during the 2001-spawning year. The first batch of eggs was received from Canada on 3/9/01. This batch #1 was one liter of approximately 400,000, eggs were transported to Boston in a refrigerated truck. Total transport time in the cooler with ice packs was approximately 12 hours.
The last three batches of eggs were from the RI NMFS broodstock.
Batch #2: Approximately 150 ml, 60,000, eggs were transported via cooler and ice pack from RI to Boston. Total travel time via car was 2 hours.
Batch # 3: Approximately 200 ml, 80,000, eggs were transported via cooler and ice pack from RI to Boston. Total travel time via car was 2 hours.
Batch #4: Approximately 150 ml, 60,000, eggs were collected between 2 spawning events. We also attempted to transport approximately 3100 yolk sac larvae to the MIT facility. Yolk sac larvae were carefully flushed with system water after acclimation to water temperature before placing in the tank.
All eggs were acclimated to the hatch system for 1 hour, disinfected with P.O.V at 200ppm for 10 minutes and rinsed for 10 minutes before being distributed into the tanks.
Summary of Results:
We had varying results from the four batches of eggs. The eggs varied greatly in quality and that was reflective in the hatch rates, See Graph 1.
Batch #1: After a 70% hatch on 3/13/01, the larvae were fed enriched rotifers. The larvae were responding well to the feed and following the typical growth for this species. On 3/22/01 there were very heavy rains in the Boston area. The hatchery is located next to the locks of the Charles River and under such conditions there is a surge of freshwater into harbor. This occurrence greatly affects our salinity and water quality. We were forced to shut down our intake pump for seven days until out intake water reached acceptable levels. Once we did begin pumping water in for recirculating system water exchanges, the salinity in our system dropped to from 29 to 24 ppt. On 4/10/01, the larvae that were successfully feeding on Artemia were all found dead in the tanks. Water and fish samples were sent out to Micro Technologies in Richmond, ME for testing. The analysis yielded a high loading of a freshwater parasite in the system. These parasites stressed the larvae and resulted in the 100% mortality. See Graphs 2 and 3 for growth and survival data.
Batch #2: On 5/4/01 eggs were picked up from RI NMFS. The chiller in the hatch system was not functioning properly so the eggs were temporarily incubated in a small aerated tank in our refrigerator. Once the chiller was operating properly, the eggs were moved to the hatchery tanks. Hatching concluded on 5/10/01 with a 53% hatch. The larvae were fed enriched rotifers and on 6/4/01 they were offered newly hatched Artemia. By 6/19/01, all larvae were dead. There was a steady decline in survival from first feeding, (see Graph 5). A high number of mortalities were observed during the rotifer to Artemia weaning process. All water quality and feed sources were normal and temperature varied little during egg incubation. See Graph 4 for growth data.
Batch #3: Eggs obtained on 5/11/01 from RI NMFS only resulted in a 25% hatch. The larvae responded well to live feed but overall, resulted in a less than optimal survival to Artemia. From 6/14/01 to 6/18/01, high mortality was observed in all tanks. Fish were weaned onto a Biokyowa feed beginning on 6/29/01. Heavy mortality was reported in the month of July. Many of the mortalities were fish with spinal deformities. Fish were sent to a MIT DCM veterinarian for analysis. Laboratory results showed that there was an external fungus inhibiting the fish as well as lateral scoliosis. The fish were treated with formalin submersion for three treatments involving one hour of exposure to 50ml/100 gallon for 3 days. This treatment was done to eliminate or minimize the fungus on the fish. The remaining fish from this batch are still housed at the hatchery. See Graph 6 and 7 for growth and survival data.
Batch #4: On 5/24/01 we received the last two haddock spawns from RI NMFS. The combined eggs were all dead by 5/30/01. A small number of yolk sac larvae were also transported to the hatchery from this spawn to be used in an undergraduate research project. All larvae were sacrificed during that experiment.
Our facility encountered several difficulties this season. Our most significant problem was the spring flood resulting in poor make up water, causing the loss of our strongest and largest batch of fish. The egg batches from the RI broodstock were of lesser quality and did not perform well this year. We continually attempted to rear the eggs though they were of poor quality. We had water quality problems as well as poor egg quality.
Objective 3) Stock one of the OOA Demonstration Project cages with haddock.
This task is not possible given the results of task 2.
Objective 4) Evaluate the growth and survivability of these fish over a May-October growing cycle.
This task is on going and will be based on the small number of fish we are holding from batch #3. We will use the growth data from this batch and from last year to refine our growth model. We will also examine out veterinary reports to better understand the roles of pathogens in causing mortalities.
Objective 5) Analyze the economics of seasonal haddock production in open-ocean cages.
This work is deferred due to lack of data.
Objective 6) Report our findings to industry and other researchers and hold demonstrations and instructional sessions on the techniques developed.
One presentation has been made at a conference in Canada by B. Moran.
Haddock Research at the MIT Sea Grant's Marine Finfish Hatchery. AAC conference May 2001, Halifax, N.S.