CINEMar/Open Ocean Aquaculture Annual Progress Report for the period 1/01/03 through 12/31/03

Principal Investigator: Larry G. Harris

I. Accomplishments

A. Scheduled Tasks

1. Complete development of hatchery and produce juvenile sea urchins during winter/spring spawning period.
2. Test suspended caging systems for growth of hatchery reared urchins and as settlement sites for natural larvae similar to spat bags for scallops.
3. Continue monitoring for invasive species likely to foul fish pens.

B. Progress on Tasks

1. The hatchery in the basement of Portsmouth Scuba was completed and four batches of juvenile urchins were produced, number over 600,000. Problems early in the winter with infections reduced the final production, but an effective sulfa drug solved the problem with the infections so that later batches had high yields.
2. Suspended caging systems were deployed at a series of sites from Portsmouth Harbor to Eastport, Maine in collaboration with urchin harvesters. The results of the initial caging studies indicated that cage design, location and manner of suspension all effected both cage survival, but survival and recruitment of urchins. Cages placed on the fish pens and at the Isles of Shoals had the highest survival and recruitment ranging from 200 to 1200 settled urchins per cage.
3. A species of bryozoan, Alcyonidium sp., was found on the mesh of the fish cages and nowhere else as yet. An highly invasive colonial tunicate, Didemnum vexillum (name in question and likely to be changed shortly to a species from the North Sea), has been found on the fish cages, having expanded it initial range in Portsmouth Harbor to the Isles of Shoals and the fish pens. The bryozoan is unlikely to interfere with aquaculture operations, but the tunicate has become a serious pest on mussel farms in New Zealand and is likely to be a problem for aquaculture in the Gulf of Maine in the near future.

C. Important Results or Findings
The utilization of suspended caging systems for both juvenile grow out and enhanced production of sea urchins through natural recruitment is new and has generated interest among urchin harvesters. The urchin fishery is in serious decline and hatcheries and suspended cages offer means for both reseeding depleted populations and sea ranching of urchins on lease sites.

The fish cages have proved to be interesting artificial reefs that may be used to identify certain new invasive species, but they may also suffer from extensive fouling by at least one of the recently introduced tunicates.

D. Difficulties Encountered
During the 2002 funding period, it was determined that suspended caging systems could promote excellent growth for hatchery reared juvenile urchins prior to out planting. It was also discovered that suspended cages might generate increased production of small urchins through natural recruitment into the cages. A large experiment was planned for the utilizing the outer supports of the fish cages to test for natural recruitment as well as growth rates of hatchery reared juveniles. At the beginning of the summer, I was informed that I would not be able to utilize the fish cages for studies during the summer of 2003 because they were being moved in order to deploy a new, larger fish pen. It turned out that only one cage was moved and only as far as the second cage where it would have worked just as well as if it had remained in its original site. There was no communication of the change in plans so that we could have proceeded with our experiments. As a result, only minimal data was obtained from the fish cage site, though those results did confirm that natural recruitment does occur and that the site would be excellent for juvenile urchin growth and recruitment.

E. Anticipated Success in Meeting Project Objectives on Schedule
The project was not renewed, so future studies will continue at sites other than the offshore fish cages.

F. Reports, manuscripts, and presentations resulting from the project
Harris, L. G., P. A. Madigan, R. L. Toppin and K. Waters, 2003. A hatchery system for Strongylocentrotus droebachiensis: tests of caging system for juvenile grow out. Sea Urchin 2003: International Conference on Fisheries and Aquaculture. Puerta Varas, Chile March 2003(Abstract).

Harris, L. G., P. A. Madigan, R. L. Toppin, 2003. Test of a suspended recruitment and juvenile grow out system for the sea urchin Strongylocentrotus droebachiensis in the Gulf of Maine. In: T. Heinzeller (ed.) 11th International Echinoderm Conference, Munich, Germany October, 2003(Abstract and Manuscript in review).

Harris, L. G., A. C. Jones, 2003. Changing distribution patterns in the invasive alga Codium fragile ssp. tomentosoides: interplay of herbivores and hydrographic conditions in the Gulf of Maine. In: J. Pederson, R. Moll (eds.) Third International Conference on Marine Bioinvasions, March, 2003 (Manuscript in review).

Mathieson, A. C., C. J. Dawes, L. G. Harris and E. J. Hehre, 2003. Expansion of the asiatic green alga Codium fragile subsp. tomentosoides in the Gulf of Maine. Rhodora 105:1-53.

II. Tasks and Activities for Next Reporting period

A. Tasks for the next reporting period
None.

III. Expenditures
The expenditures were within the anticipated range and adequate to complete the work outlined.