World Aquaculture December 2019

WWW.WA S.ORG • WORLD AQUACULTURE • DECEMBER 2019 23 Molluscs Four large commercial oyster and clam hatcheries (Hawaiian Shellfish LLC, Jamestown Point Whitney Ventures, Kona Coast Shellfish LLC, Taylor Shellfish) and two research hatcheries (PACRC and Pacific Hybreed) operate on Hawaiʻi Island. These hatcheries supply a significant amount of oyster and clam seed to the West Coast shellfish industry and new Hawaiian farms. The Hawaiʻi hatcheries are also important on a national basis and have been a lifeline toWest Coast producers, whose hatcheries have been affected by ocean acidification. Hawaiʻi has a long history growing bivalve molluscs such as oysters and clams, with first efforts focusing on non-native species. The Pacific oyster Crassostrea gigas is the main culture species with modern farming efforts starting in 2010, when the Department of Health began to implement elements of the State Shellfish Plan that pertain to water quality monitoring and classification of shellfish growing areas. Currently production efforts are developing on Kauai, Hawaiʻi Island, Oʻahu and Molokai. Kualoa Ranch now operates the largest oyster farm in Moliʻi fishpond. Eastern oysters Crassostrea virginica and Kumamoto oysters C. sikamea have also been cultured. Limited numbers of Eastern oysters still exist in Pearl Harbor, where they were first introduced in the 1860s. The PACRC is working to “rescue” these relic stocks for future aquaculture use. Hawaiʻi was also the site of early attempts to developed land- based oyster culture systems in intensive raceways (Yamaguchi et al. 1983). The PACRC is currently testing a similar system using fish effluent in partnership with the newly incorporated Hilo Aquaculture. The Big Island Abalone Corporation at HOST park has been producing abalone, primarily for export to Japan, for over twenty years. Pearl farming has also been tested in Hawaiʻi and the USAPI. A new effort is currently underway with oyster and pearl farming is underway for Hilo Bay. Opihi (Hawaiian limpets) are another high- value mollusc that has spurred considerable research (Hua 2014) but there is no commercial production to date. Most recently, native Hawaiian oysters Dendostrea sandvicensis are being used by the Waiwai Ola Waterkeepers for water quality mitigation purposes at six sites and trials for commercial production are overseen by the PACRC staff. Microalgae and Seaweeds Large-scale production of mi- croalgae was started at HOST Park in 1983 by Cyanotech Corporation, which began with Spirulina and now produces Haematococcus pluvialus for the ex- traction of astaxan- thin. The vertically integrated company now utilizes 90 acres of ponds and has its own processing plant. Several other companies have entered the field over the years, many of which focused on research. Interest in seaweed culture is also on the rise. Hawaiians use over 70 species of seaweed (called limu in Hawaiian), but now only three species are regularly cultured and two of these are non-native. Most of the commercial seaweed production comes fromRoyal Hawaiian Sea Farms (HOST park), Olakai, Inc. (Oʻahu) and smaller operations around the State. Olakai Inc. also produces sea asparagus Salicornia spp. in its shrimp ponds. Limu is still collected from the wild, but there is concern that over-collecting, restriction of freshwater flows and environmental degradation are negatively impacting wild populations (McDermid et al . 2018). This ledWally Ito to establish a small demonstration facility for native seaweed species at AFRC (Fig. 5), the non-profit Kuaʻāina Ulu ʻAuamo (KUA). KUA convenes the limu hui (group of seaweed practitioners) to bring awareness to the need to protect seaweed species and their environment and to work towards restoration and culture of native species. Researchers at UHHwere partially successful in closing the life cycle of Asparagopsis taxiformis ( limu kohu ), a high-value, iconic Hawaiian seaweed. The news that feeding limu kohu to cattle can nearly eliminate methane production has stirred new interest in this species. Other Species Hawaiʻi has a long history of research on diverse species, many of which have not found their way into commercial aquaculture, yet remain of interest. One of the most innovative efforts involves culture of collector urchins Tripneustes gracilis as a biocontrol to curb the growth of invasive seaweed that smothers native corals (Fig. 15). Outplanted urchins graze on the invasive species, giving native coral species a fighting chance to grow back. The sea urchin hatchery at AFRC has released over 500,000 sea urchins on more than 60 acres of impacted area over the last eight years. The urchins are successful in ( C O N T I N U E D O N P A G E 2 4 ) FIGURE 14. John Dobovan and Aimee Greenwood of Kulahaven Farm, which produces rainbow trout and watercress. Photo: John Dobovan. FIGURE 15. Small sea urchins produced at the AFRC (top) and after out planting on a reef to fight invasive seaweed (bottom). Photo: David Cohen, DAR.