FishConsultGroup's video: Seed production of red abalone Haliotis rufescens in Monterey region California USA

Video description: Peter Hain (USA) and Abdel Rahman El Gamal (Founder of the video channel) I filmed this video during my visit to this facility in January 2015. Mr. Peter Hain, the manager of the facility who toured me around the facility. This facility is located in “Moss Landing” in the Monterey region, California. The hatchery component was described verbally as we were out of the spawning season, while the spat nursing was adequately covered. Source of hatchery broodstock: There are two sources of the red abalone broodstock: From the wild: Gravid abalone females and males are collected in season at a site north of Fort Ross, California, under permit from the California Department of Fish and Wildlife. From other farms/hatcheries: Gravid females and males are also purchased as needed from two commercial abalone farms. Sex ratio of broodstock: In general a ratio of three females to every male is used when spawning commercial farm broodstock. The ratio can be reversed if crossing large wild females with smaller farmed males. Spawning season: Wild abalone broodstock from the Northern California coast are generally gravid during the months of March and April. The hatchery phase generally begins in May and extends into June and July. Water source and quality during the hatchery operations: Filtration: Filtration through sand filters (20 microns). Sand filtered seawater is delivered to the hatchery from the pumping station. The seawater intake is located approximately 300 meters offshore at 16.6 meters depth. Hatchery water is further filtered through 20 microns, 10 microns, and 5-micron cartridge filters. Sterilization: A UV sterilizer is used during the spawning of the adults and hatch-out of the larvae. The UV sterilizer is generally turned off on Day 3 of the eight to nine-day larval cycle to introduce the larvae to the natural mix of bacteria present in the seawater. Fecundity: Large wild females can spawn upwards of eight million eggs with smaller, 4-5 inch, farm animals producing up to one million each. Incubation: Fertilized eggs will generally hatch in eighteen to twenty hours, dependent on temperature, as trochophore larvae at which point they are transferred to a conical bottom tank with flow-through water and retained with 70-micron banjo screens. Larval rearing tanks: The conical bottom larval rearing tank holds 454 liters and the ideal density is around five larvae per milliliter. Production cycle: The hatchery production cycle lasts 8-9 days, depending on temperature, generally 13-15 C. Abalone Nursing Nursing capacity: Based on the current volume of nursery tanks, the capacity of the nursery facility is 120,000 – 130,000 abalone spat (seed). Water passes through sand filters which filter down to around 20 microns. The filtered water is directed to nursery tanks as required. Water temperature: 15C is considered ideal but the range is generally 12 to 16C. Regarding salinity, abalone prefers oceanic salinity of 32-36 g/L and will suffer mortality if salinity drops below 25 g/L for an extended time. Nursing tanks: There are four nursery tanks of 5x10 feet with a depth of 50 cm and four tanks 2x8 feet. Nursing tanks are equipped with settling racks, holding corrugated fiberglass sheets, are locally made of PVC to provide a large surface area. The surface area available for settlement in each of the large tanks exceeds 125 square meters. The settlement racks sit off the tank bottom on an aeration manifold made of PVC pipe. Management of nursing phase: Nursing tanks are filled with the filtered water 3-5 days before the introduction of larvae from the hatchery and a slow flow is maintained over the settlement racks. This practice allows a bacterial coating, the first food of the abalone, to be established on the corrugated sheets. Abalone larvae are settled into the tanks and distribute onto the corrugated sheets. Diatoms of 10 microns are inoculated into the tanks the day after settlement of the abalone larvae. Tanks are left uncovered for several days until the diatoms are established and then the tanks are shaded with the three layers to slow further diatom growth. Spat-diatom ratio: Once the settled spats are seen grazing on the diatoms, one of the three shades is removed to encourage the growth of diatoms. The same process is repeated depending on the spat-diatom ratio. Diatom growth is strictly regulated so as not to overgrow the abalone while at the same time keeping sufficient diatoms available as the juveniles graze. Collecting grown spats: When the spats are ready for farming, they are collected and graded. During the visit, there were four graders. The largest size could reach about 1-g while the smallest can be 0.25g Sampling: Settled juveniles are counted when they become visible so that populations can be adjusted as necessary. Periodic length measurements are taken to check the rate of growth.