Progress 09/15/03 to 09/14/06
Outputs
I. A study to evaluate the risk of ciguatera fish poisoning from consumption of reef fish grown at marine aquaculture facilities in Hawaii. No additional progress from that reported in 2005 has been made. However, the increase in consumer confidence due to the reduction in the threat of the ciquaterra toxin and the absence of the tapeworm in the farm raised fish has provided impetus for expansion of these industries. II Biosecurity Risk Mitigation Model for Hawaii Shrimp Aquaculture. A test-action biosecurity risk framework was developed according to decision-theoretic principles. Two major benefits of modeling WSSV import risk based on the test-action framework are (1) the ability to evaluate policy networks (sequences of decisions) and (2) the ability to estimate the expected benefit of biosurveillance. Traditional approaches to evaluating biosecurity risk, in contrast, compare fixed-policy alternatives, estimate risk qualitatively, or ignore the separate impact of
biosurveillance. Based on the test-action framework, a Bayesian decision network (BDN) was implemented using GeNie 2.0 (University of Pittsburgh) to model WSSV import risk. The BDN implementation of WSSV import risk model permits the incorporation of uncertainty, provides us with efficient algorithms for quantifying the impact of biosecurity policies, and determines the optimal strategy based on expected outcomes and value of information from biosurveillance. A preliminary macro structure of the BDN for WSSV import risk in Hawaii was presented at the Aqua 2006 conference in Florence, Italy. The WSSV import risk BDN models the impact of import restrictions, local SPF zoning scenarios, and surveillance. Verification of components of the model is currently under way. Parameterization of the model has also begun, including estimates of WSSV prevalence based on trade data and documented WSSV occurrences, direct biosurveillance costs (e.g. PCR testing), financial impacts based on port-level
trade data, and farm losses based on available APHIS indemnification reports.
Impacts
Kona Kampachi (TM), from Kona Blue Water Farms, is the Hawaiian yellowtail fish, farm-raised in the offshore open ocean cages. It is derived from the open ocean fish, Kahala. The research conducted in this project, compared open ocean wild caught Kahala from the cage raised farmed Kahala (now called Kampachi). Wild caught Kahala are subject to Ciquaterra toxin poisoning and the presence of a tapeworm. Research from this study confirmed the absence of these problems in the farm raised fish. Kona Kampachi (TM) has been a marketing success; marketed as Sushi and Sashimi grade fish but also for cooking. See their web site: http://www.kona-kampachi.com/. The story of the Kona Kampachi (TM) can be summarized in this Honolulu Star Bulletin Feature. http://starbulletin.com/2005/09/28/features/story1.html. Funding from this grant helped solidify the success of this product and reduce consumer concerns about the safety of open ocean farm raised fish. Testing of the Risk
Mitigation Model continues with commercial shrimp farmers. It is expected that this model can manage the risks involved in raising shrimp commercially - including the impacts of disease.
Publications
- Kam, L.E., P.S. Leung, & C.S. Tamaru (2006). Developing a Biosecurity Risk Framework for the Prevention of White Spot Disease (WSD) in Hawaii Shrimp. World Aquaculture 2006, Florence, 9-13 May 2006, p. 440. Baton Rouge: World Aquaculture Society.
- R. Yu, P.S. Leung and P. Bienfang. 2006. Predicting shrimp growth: artificial neural network vs. nonlinear regression models. Aquacultural Engineering (in press)
- R. Yu, P.S. Leung and P. Bienfang. 2006. Optimal production schedule in commercial shrimp culture. Aquaculture 254:426-441.
- Kam, L.E.Y.W. 2006. A Bayesian Decision Network Model for Analyzing Biosecurity Risk. Ph.D. Dissertation, University of Hawaii.
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Progress 10/01/04 to 09/30/05
Outputs
I. A study to evaluate the risk of ciguatera fish poisoning from consumption of reef fish grown at marine aquaculture facilities in Hawaii. Grow-out facilities for two commercial fish farms in Hawaii (e.g., Cates International and Kona Blue Water Farms) were surveyed for the presence of the marine dinoflagellate, Gambierdicus toxicus. No signs of the dinoflagellate were detected in the land based grow-out facilities at Kona Blue Water Farms. In contrast, G. toxicus could be found on all three submerged sea cages operated by Cates International and levels that ranged between 1 to 1,921 cells G. toxicus/gram algae. The major algal species that was growing on the cages and associated with G. toxicus was identified as Tolypiocladia glomerulata. The low levels of the dinoflagellate are consistent with number of cases (3.6 cases/100,000 population) reported for ciguatera poisonings in Hawaii. Fish specimens from these facilities were also tested using a membrane immunobead
assay for detecting ciguatoxin and related polyethers directly from fish tissue. To date a total of 40 individual Pacific threadfin and 40 kahala intercepted through the normal marketing chain have been examined and none have been found to possess the ciguatoxin(s). These findings indicate that ciguatoxin(s) are prevented from entering the culture process for both S. rivoliana and P. sexfilis raised in aquaculture facilities even when G. toxicus is present. A total of 45 wild-caught amberjack, were caught by hook and line in waters surrounding Oahu, Hawaii. Comparison of the two common species, Seriola dumerili and Seriola rivoliana, yielded no significant difference in possessing the tapeworm trypanorhynch plerocerci in the body musculature. When the data sets of the two wild-caught kahala species were combined, the results showed that 80 percent (36/45) of these kahala were infected. This was significantly higher than the percentage observed with commercially-farmed kahala, as none
of the cultured specimens (n=40) were found to possess any evidence of trypanorynch plerocerci. The results from the current investigation indicate that the technology for the artificial propagation of the kahala, and in particular, S. rivoliana, has broken the life cycle of this particular tapeworm and has eliminated its presence in the farmed product. II. Optimal harvest strategies for farmed fish and shrimp in Hawaii. The model by Yu and Leung (2005) which incorporates the multi-cycle and multi-pond nature typical of commercial shrimp farms operating on a year-round basis has been extended to analyze the impact on the optimal production schedule and its resulting economic performance of shrimp farming from variability in survival rate, growth rate, price seasonality and labor force constraints. It has been demonstrated that application of the model could potentially increase the profitability of multi-pond, multi-cycle shrimp farming operations.
Impacts
The investigations have provided an increase in consumer confidence that the Hawaii farm-raised fishes are safe to consume. Evidence of this growing confidence has resulted in a recent $4 million dollar investment into Kona Blue Water Farms off shore cage culture operations that seeks to increase production of the amberjack (See http://www.bizjournals.com/pacific/stories/2005/01/24/daily51.html). Kona Blue Water Farms would receive the Hawaii Venture Capital Association's 2004 Venture Capital Deal of the Year award.
Publications
- Yu, R., Leung, P.S. and Bienfang, P. 2005. A decision support system for efficient scheduling of multi-pond and multi-cycle commercial shrimp culture. In Chapter 21 of Shrimp Culture: Economics, Market and Trade. Blackwell Publishing.
- Yu, R. and Leung, P.S. 2005. Optimal harvesting strategies for a multi-pond and multi-cycle shrimp operation: a practical network model. Book of Abstracts World Aquaculture 2005: Bali, Indonesia, p. 330.
- Yu, R. and Leung, P.S. 2005. Integrating an artificial neural network model with the optimal scheduling model: Application to a commercial shrimp farm. Presented at the Triennial International Federation of Operational Research Societies (IFORS) 2005, Honolulu, Hawaii, July 11-15.
- Tamaru, C.S., Anderson, B., Hokama, Y. and Vincent, D. 2005. Evaluating the risk of ciguatera fish poisoning from consumption of reef fish grown at marine aquaculture facilities in Hawaii. World Aquaculture Society Conference, May 9-13, 2005. Bali Indonesia.
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Progress 10/01/03 to 09/30/04
Outputs
Macroalgae (tentatively identified as Tolypoiclaida glomerulata) from all three submerged sea cages have been sampled over the course of the project. All samples to date and on all cages have resulted in the detection of Gambierdiscus toxicus, the dinoflagellate known to be the cause of ciquatera toxicity. Pacific threadfin or moi, Polydactylus sexfilis, a carnivorous species, housed in these cages, have not shown any positive samples for the toxic dinoflagellate. Results from Kona Blue Water Farms shows that there are no indication that the ciquatera dinoflagellate exists on their cages. All samples collected from the amberjack or kahala (Seriola riviliana) have shown no positive tests for the ciquatera toxin. Examination of wild caught kahala off of Oahu has shown a prevalence for a parasite that is embedded in the muscle tissue of the fish. The parasite is a cestode (tapeworm) and is a juvenile state called a plerocercoid that develops to maturity in an
elasmobranch. Infestation in wild caught kahala is high (>80% infected) and to date, none of cultured kahala have had the parasite. It appears that the culture process has broken the life cycle of this particular parasite. The parasite has been tentatively identified as Pseudogrillotia zerbiae.
Impacts
Results have provided an increase in consumer confidence that the Hawaii farm raised fishes are safe to consume. Evidence of this growing confidence has resulted in a recent $4 million investment into Kona Blue Water Farms off shore cage culture operations that seeks to increase production of the amberjack (Pacific Business News, 1/27/05, http://www.bizjournals.com/pacific/stories/2005/01/24/daily51.html). Ciquatera results have been used to counter concerns about ciquatera poisoning in these fish. The results obtained regarding the tapeworm will help the marketing of the amberjack since one of the primary markets is the sashimi market. Although, the parasite does not pose any human risks, aesthetically, the presence of these worms in the flesh is not appealing to the consumer.
Publications
- No publications reported this period
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Progress 10/01/02 to 09/30/03
Outputs
No progress to report. This project was initiated on September 15, 2003.
Impacts
No impact to report. This project was initiated on September 15, 2003.
Publications
- No publications reported this period
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