Recipient Organization
Pacific Planktonics
(N/A)
Kailua-Kona,HI 96740
Performing Department
(N/A)
Non Technical Summary
This project investigates the feasibility of producing high value ornamental reef fish that have not been raised before, and reducing the cost to farm these fish. The market for ornamental reef fish is very large, but that market is supplied primarily by wild fish captured from tropical reefs. Hatchery technology is only marginally successful for most reef fishes. Success in this project will increase the number of fish species we can raise profitably, and may indirectly reduce fishing pressure on reefs in Hawaii and elsewhere. If the Phase II project is successful, we will be able to raise ornamental reef fish competitively, and expand species numbers to provide crop diversity and income security. We hope to compete in the rising aquaculture market, where customers appear to be willing to pay a slightly higher price for fish that are not captured with cyanide or dynamite. This aspect of aquaculture also has social and conservation benefits, especially in Kona where
Fisheries Restriction Areas (FRAs) have been established to keep collectors away from 31% of the reef.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
Our commercial goal is to raise fish that have not been raised before, and to do so profitably. Our long term goal (Phase III and beyond) is to expand the number of species we culture for better market flexibility. Specifically, we want to raise tangs, butterflyfishes, angelfishes, wrasses and other fishes whose larvae are too small to culture with the best standard methods. Our Phase I goals are to develop methods to culture a representative model of ornamental reef fishes using ciliates as a first feed, and to reduce the cost of culturing copepods. In order to determine the feasibility of our goals, we need to answer these technical questions: 1-Are the nutritional values of Euplotes ciliates comparable to calanoid copepods in amino acid and fatty acid profiles? 2-If not, can ciliate nutritional values be enhanced to support larval fish growth? 3-Are calanoid copepod culture densities affected by water exchange rate or algal species? 4- Is larval fish survival or
growth affected by ciliate density or water exchange?
Project Methods
We plan a series of 12 separate tests, each lasting 10 days, to compare the survival of fish fed copepods (the control group for all tests) or ciliates (the treatment groups) under different conditions. Fish that do not feed die 6 days after hatch. Fish that feed poorly may last until 7 or 8 days after hatch. By 10 days, well fed fish have grown and may have some fin development. The control group will be flushed with 1 volume of water per day. Five of the tanks will be fed copepods once daily, to replace flushed and eaten plankton and keep copepod density above 500 nauplii per liter. The fish in the other five tanks will be fed ciliate culture every 2 hours daily from 7a.m. until 5 p.m.. Ciliate density will be monitored and adjusted as needed to keep ciliate density at the specified level in the larval fish environment. Ciliate density, water exchange, and ciliate nutritional value findings will be used to modify our methods, and these larval fish bioassays will be
repeated as needed to confirm our findings. Ten day bioassays will compare larval fish survival for fish fed copepods, plain ciliates, enriched ciliates, 1 or 10 or 20 ciliates per milliliter, and water exchange rates of 1, 2, or 10 volumes per day. At the end of the ten day test, all tanks will be drained into 283um sieves that let feed pass through, but retain live fish larvae. Fish will be counted as live as long as their tissues are not necrotic (opaque). Ciliate types are Algamac 2000 enriched (A), Culture Selco enriched (CS), and normal unenriched (N). Best results from each series of tests will be applied to optimize subsequent tests, then repeated to cover each variable. This plan is governed by several constraints. We need to stock at least 400 eggs per tank in order to obtain statistically comparable numbers of survivors at the end of each test. It is difficult to find a few dozen surviving larvae (less than 3mm total length) in 1,000 liters of algae and zooplankton. Egg
numbers are not expected to exceed 10,000 per spawn, and daily spawns are not expected. We will analyze survival results with a Mann-Whitney U-test. The null hypothesis is that there will be no difference in survival between the two fish groups (5 ciliate fed, and 5 copepod fed). We anticipate that some trials will show good survival of the copepod group, and no survival of the ciliate group. If things go according to plan, at least one trial will show no survival difference, or a difference that can be assessed by a non-parametric sum of ranks test like the Mann-Whitney U-test (Kraul, et al. 1993). With five tanks for each treatment, and with the variability we normally see in identical treatments, one group would be significantly (p=0.05) different from the other if it had about 50% greater survival. However, if ciliates give us only 50% of the survival of the control group, they may still provide the cheapest feeding regime.