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May 8, 2014
Production of Penaeus monodon Postlarvae
Hank Bauman (email@example.com), Hatchery and Broodstock Manager at Paradise Shrimp Farm, Dangriga, Belize, reports:
Over the last two past decades low numbers of tiger shrimp (Penaeus monodon) have been found in harvests of wild shrimp from waters off South Carolina, the Gulf of Mexico, the Caribbean Coast of Central and South America and the Atlantic Coast of South America as far south as Brazil.
It is not uncommon to find a handful of P. monodon in harvests of white shrimp (P. vannamei) in shrimp ponds in Belize. How do they get into the ponds? The current thinking is that the wild monodon postlarvae enter the ponds when they are being filled with water.
Bauman reports that his technical team has successfully produced first generation postlarvae from “Caribbean” tiger shrimp. The “first generation parent shrimp” were collected from several of Paradise’s ponds during harvests from June to December 2012. A small number of monodon females and males (weighing from 50 to 120 grams) were recovered from white shrimp pond harvests after 125 days, or so, of growout, and transferred to a quarantine tank for initial acclimation, observation and disease evaluation. The shrimp thrived and appeared healthy, but growth was slow because this trial occurred during the winter months, and the water in the outdoor, unheated, quarantine tank was cool. During this period the shrimp were fed EPIFEED® MBF dry feed (Epicore BioNetworks, Inc.) and Purina® 30% protein shrimp pelleted feed. Survival was very high.
Cooperating with the Belize Aquaculture Health Association (BAHA), some of the monodon in acclimation (as well as postlarvae later on) were sacrificed for testing. BAHA sent tissue samples to the University of Arizona’s Aquaculture Pathology Group for PCR and histology testing. Thus far, all of the laboratory results indicate that the monodon met or exceeded the SPF standards applied by BAHA for shrimp farms in Belize.
Following health clearance, 6 female and 13 male adult monodon were transferred to an indoor tank in one room of Paradise’s white shrimp maturation building for pre-maturation conditioning. The maturation tank was five meters in diameter with water filled to a depth of 75 centimeters. The heated water in the maturation area varied from 27° to 31°C, depending on the season. Every night, 80 to 90% of the water was exchanged with pre-heated water; no water was recirculated. Photoperiod was controlled in the maturation room with 12 hours of light (on at noon) and 12 hours of darkness (off at midnight).
The maturation diet was the standard diet used at Paradise Shrimp Farm for vannamei maturation (bloodworms, squid, Artemia biomass and EPIFEED® MBF dry feed. One month prior to ablation, the monodon were fed six times a day and maintained on the above diet throughout the maturation and spawning period.
The salinity was adjusted to 27 parts per thousand. Bauman believes that modestly lower salinity is a key factor in stimulation natural mating in monodon. The idea of lowering salinity to stimulate spawning was based on observations he made in the Philippines, where one month after the rainy season began, which lowered salinities, millions of monodon postlarvae appeared on the shores of Iloilo Province. The optimum salinity may actually have been a bit lower than that, but after hatching, he found that it was important to put the nauplii in a tank with at least 28 ppt salinity.
For the trials in Belize, at approximately six weeks following ablation and six days after dropping the salinity to 27 ppt, spawning activity started in the monodon tank. Because the primary purpose of the system was production of postlarval white shrimp, the monodon tank was managed with less attention, and mature females were not always removed from the maturation tank and stocked into a spawning tank. However, over a period of approximately three months, the six females produced over 14 million nauplii. The females continued to grow and are currently over 250 grams and the males are over 200 grams. On two occasions one of the largest females produced 900,000 nauplii.
Nauplii stocking and larval rearing were carried out as space and resources permitted. Nevertheless, over five million PL-15 “Caribbean” monodon postlarvae were harvested with an average survival of 37% (nauplii to PL-15).
The results to date demonstrate that maturation, natural mating, spawning and larval rearing to the postlarval stage is feasible for “Caribbean” monodon. Bauman plans to continue his work on developing commercially viable tiger shrimp farming in Belize.
Source: Email to Shrimp News International from Hank Bauman. Subject: Tiger Shrimp in Belize. May 7, 2014.
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