Hatchery Technology of
GROUPER
Kingdom: AnimaliaPhylum: ChordataClass: ActinopterygiiOrder: Perciformes Family: Serranidae
Taxonomic Classification
Overview Most popular species in the reef food fish industry in Asia-
Pacific region Fast growing, hardy ,suitable for intensive culture Excellent characteristics for processing due to unique
culinary attributes and scarcity In 1997, the Asia-Pacific Region contributed about 90% to
the world Aquaculture prdxn w/ Grouper at 15000 ton w/ China as the biggest producer contributing 8000 tons followed closely by Indonesia. Other countries in the region commonly produces 1000-2000tons annually in 1990-1997.
Although grouper culture is widespread in Asia and Pacific, its continued dvlp. is constrained by the limited availability of fingerlings. Most economies w/recent exception of Chinese Taipei, rely almost totally on wild-caught fry and fingerlings for stocking.
The word "grouper" comes from the word for the fish, most widely believed to be from the Portuguese name, garoupa. The origin of this name in Portuguese is believed to be from an indigenous South American language.
In Australia, the name "groper" is used instead of "grouper" for several species, such as the Queensland grouper (Epinephelus lanceolatus).
In the Philippines, it is named lapu-lapu in Luzon, while in the Visayas and Mindanao it goes by the name pugapo.
In New Zealand, "groper" refers to a type of wreckfish, Polyprion oxygeneios, which goes by the Māori name hāpuku.
In the Middle East, the fish is known as hammour, and is widely eaten, especially in the Persian Gulf region.
Groupers are teleosts, typically having a stout body and a large mouth. They are not built for long-distance, fast swimming. They can be quite large, and lengths over a meter and weights up to 100 kg
They habitually eat fish, octopuses, and crustaceans. Some species prefer to ambush their prey, while other species are active predators.
Their mouths and gills form a powerful sucking system that sucks their prey in from a distance. They also use their mouths to dig into sand to form their shelters under big rocks, jetting it out through their gills. Their gill muscles are so powerful, it is nearly impossible to pull them out of a cave if they feel attacked and extend those muscles to lock themselves in.
LIFE CYCLE
Many species move to particular areas at the same time each year to reproduce in spawning aggregations. In these aggregations, females release eggs (some larger individuals produce over 1 million eggs) and these are fertilized by sperm released by males. The fertilized eggs hatch to very small forms (larval stages) which drift in ocean currents for 1 to 2 months. Less than one in every thousand of the small floating forms survives to settle as a juvenile in shallow water near reefs. As they grow, they move onto coral reefs and less than one in every hundred of the young fish (juveniles) survives to become an adult.
drifting larval stages
juveniles
1-2 months
reef
3-7 years
Spawning aggregations in many species
REPRODUCTIVE BIOLOGY
Groupers are mostly Protogynous Hermaphrodites, they mature only as females and have the ability to change sex after sexual maturity
Some species of groupers grow about a kilogram per year and are generally adolescent until they reach three kilograms, when they become female.
The largest males often control harems containing three to 15 females.
Groupers often pair spawn, which enables large males to competitively exclude smaller males from reproducing.
However, some groupers are gonochoristic.
Gonochorism, or a reproductive strategy with two distinct sexes, has evolved independently in groupers at least five times. The evolution of gonochorism is linked to group spawning high amounts of habitat cover.
Both group spawning and habitat cover increase the likelihood of a smaller male to reproduce in the presence of large males.
Gonochoristic groupers have larger testes than protogynous groupers (10% of body mass compared to 1% of body mass), indicating the evolution of gonochorism increased male grouper fitness in environments where large males were unable to competitively exclude small males from reproducing
PROXIMAL CAUSES OF SEX CHANGE IN PROTOGYNOUS HERMAPHRODITE
CAUSES
Removal of males from the population leads to sex change in the dominant(largest) females.
The sex ratio would depend upon the current spawning sex ratio within the aggregation, the proportion of adults surviving to spawn in subsequent years, and the proportion of inshore juveniles surviving to mature and enter successive aggregations.
Some grouper population, males are more or less absent ‘till age 10
In case of Red grouper( Epinephalus morio), the sex ratio is not equal until age 15.
Some Grouper can live 20 years or more!
Fishing
Huntsman and Schaaf (1994) point out that both protogynous and gonochoristic (separate sexes) population tends to lose reproductive capacity as fishing pressure increases.
In protogynous stocks, however, increased fishing mortality might reduce the relative abudance of males by reducing the abundance of older-classes and diminish the probability that eggs will be successfully fertilized
Loss of behavioural interactions between male and female
Combined with continued interaction between females, (Koenig et al. 1999) suggested that the loss of male-female interaction in Gag grouper (Mycteroperca microlepis) occur at the endof aggregation period, when females purportedly return to swallower inshore waters.
To date:Only specie of grouper investigatedRed hind(Epinephalus guttatus) and coney
(Epinephalus fulva) have been histologically proven to be protogynous hermaphrodites but;
Collin(1992) groupers that aggregate are not necessarily protogynous.
Ex: Nassau grouper(Epinephalus stiatus) and Yellowfin grouper( Mycteroperca venenosa), neither of them shown to be protogynous but both known to aggregiate.
Nassau grouper (Epinephalus stiatus) spawns in very large aggregations( thousands to ten thousands of fish) for only a few weeks of the year.
In contrast, male and female Gag grouper (Mycteroperca microlepis) and Red hind (Epinephalus guttatus) co-occur only during spawning season.
ARE GROUPERS AVAILABLE ANY TIME OF THE YEAR?
COLLECTION AREA MONTH GROUPER SIZE
Peninsula Malaysia, east cost
November to December
Average 2cm
Indonesia(e.g., Banten Bay)
February to April Fry
Thailand, coastal waters near mangrove areas
January to March 7.5-10 cm fingerlings
Philippines, variable peak season in diff. Province
Peaks mostly in June to December or October to November and April to May
Tinies, fry and fingerlings
COMMONLY CULTURED SPECIES
Brown Marbled Grouper, carpet cod, flowery cod, blotchy rock cod
Epinephelus fuscoguttatus (Forsskal)
Lapu-lapu
Orange spotted grouperEpinephelus coloidesLAPU-LAPU
Dusky tail grouper Epinephelus bleekeri (Vaillant) Lapu-lapu
HATCHERY DESIGN
HATCHERY DESIGN Key
component: Regardless of scale is the implementation of biosecurity to reduce the incidence of disease, (VNN)viral nervous necrosis.
ENTRANCE OF HATCHERY FACILITY
VNN (VIRAL NERVOUS NECROSIS)
A common disease problem in marine finfish hatcheries affecting most cultured marine finfish species, including grouper .
Caused by a nodavirus also known as viral encephalopathy and retinopathy.
Symptoms are disorientation of fish ,change in color, becoming more dark.
Can be reduced by strict biosecurity. .
KEY FEATURES FOR BIOSECURITY
Separation of various functional areas; Access to hatchery limited only to
essential personnel; Disinfection and thorough cleaning of
all equipments; Routine monitoring for pathogens and
disease; Optimisation of water quality and
nutrition to improve overall health and resistance of larvae.
HATCHERY OPERATION
BROODSTOCK ACQUISITION
1. Collecting and purchasing of wild fish in a wide range of sizes.(Epinephelinae, protogynous hermaphrodites).
In Philippines size of mature female(2.2 kg),and male (3.5 kg).
2. Grow fish produced in the hatchery (in cage, pond, or tanks) however, takes 4years to grow juvenile Tiger Grouper up to broodstock size .
CRITERIA FOR BROODSTOCK SELECTION
Normal body shape and colour Absence of skeletal deformities Overall healthy status i.e., absence of large
wounds haemorrhages, infections, and parasites
Normal behavior, i.e., good response to food distribution
Best growth and food conversion rate within this age group.
TRANSPORT REQUIREMENTS FOR BROODFISH
Transported in dark-coloured, covered tanks containing aerated or oxygenated water, to reduce stress.
Dissolved maintained at >75% saturation at all times.
Mild sedation(using approved sedatives for fish) to reduce stress and for easier and safer handling.
Fish should not be fed at least 24 hours before hand to prevent faeces and regurgitated feed from fouling transport water.
TREATMENT BEFORE STOCKING Quarantine the fish To reduce the opportunity for new fish to transmit
parasites or diseases to the established fish. Quarantine process-takes between 1and 4 weeks in small tanks(0.5-2 cubic meter)to facilitate water exchange and fish handling.
This period focuses on reducing parasite load of fish regularly by placing them in freshwater bath for 5 min. to eliminate common parasites (skin flukes, protozoans etc.)
If water quality in broodstock tanks markedly different form previous holding environment, fish acclimation by placing them in a tank filled with original water, and slowly add new tank water for up to 1 hr. before releasing them into the tank.
BROODSTOCK TANKS
Tank size. When fish is(>10kg.) size ranges bet.50-100cubic meters. Preferred tank color. Medium-range blue, brown or grey not very light or
dark-shades.
Depth. 2m preferably >2.5 to allow sufficient room for spawning behavior.
Broodstock tanks are roofed in order to reduce the growth of algae on tank walls making egg collection difficult and increasing egg parasite infestation.
Dirty tanks must be cleaned frequently w/c may stress broodstock and cause spawning failure or lower quality spawned eggs.
Continously supplied with fresh seawater at daily exchange rate of 200-300%. Seawater should be filtered and clear with stable salinity (33-35ppt) and water temperature (27-30.5 degrees celsius).
Tanks located outside are subject to the natural photoperiod, while indoor may be provided with artificial lightning to simulate different photoperiod regimes.
TANK CLEANING
Siphoning of excessive feed that accumulate on bottom to prevent water quality degradation.
After spawning remove excess dead eggs w/c decay and pollute the water .
Broodstock should be bathed in freshwater for 5-7 min. During tank cleaning to reduce incidence of parasite infestation.
BROODSTOCK MANAGEMENT
Feeding
feed to satiation (6x a week),w/fish (4x a week) ,w/ squid(2x a week)
Feeding may vary, depending on availability of fish and squid.{herrings and mackerels are commonly used as feed}
Feed is supplemented with a vitamin mix included at 1% of feed. Commercial or custom-formulated vitamin mixes can be used.
COMPONENTS OF FEED MIX
Ingredients Amount
Minced fish, squid, shrimp, etc.
793g
Rice flour or other finely ground starch product
195g
Transglutaminase B 10g
Vitamin mix 1-2g(depending on recommended inclusion rate)
Total 1kg
PROPAGATION
NATURAL SPAWNING
o Occurs at night 9pm-3am for 3-6 nights each month during the new moon phase. However, studies shown that they spawn throughout the year.
o 0.8-6.0 M eggs each night.
o cease to spawn when temperature drops around 25 degrees celsius.
IMPORTANT ENVIRONMENTAL PARAMETERSph 7.5-8.3
temperature 25-32 degrees celsius
salinity 20-32 ppt
Dissolved oxygen 4-8 ppm
NO2-N(Nitrogen Nitrite) 0-0.05 ppm
Unionized ammonia < 0.02 ppm
Australian Center for International Agricultural Research ,2012
INDUCED SPAWNING
Prior to Induction: after acquisition of broodfish is stocked at concrete tanks at 6-12 months;
Stocking density:1/2 cubic meters; Feed: fed daily with fresh trashfish; Feeding rate: 5% body weight; Tank water:50-70% is changed daily. And condition simulating the natural
environment.
INDUCED SPAWNING CONTINUE…
o Species selected for induction: female-having mean egg diameter of 400ug. male- with running milt.o Ratio: female to male is 10:4o Weight range: female(3.6-6.5 kg),male(10-16
kg). o Hormones used: Human Chorionic
Gonadotropin(HCG), Pituitary Gland(PG),Luteinizing Releasing Hormone –a (LRH-a).
o Hormone administration type: Multiple dosages.
INDUCTION PROCEDURE
First injection, at dosages of 500 IU HCG + 3mg of PG per kg of fish, and at final injection at 1000 IU HCG + 3mg of PG per kg of fish at an interval of 24 hours, results showed that treated fish spawned naturally in spawning tank 12 hours after final injection.
o However, at lower dosages of 500 IU HCG + 3mg of PG at 24-hour intervals or using 10 mg LRH-a at 12-hour intervals, eggs can be artificially fertilized.
In cases where ovulation did not occur after the second injection,a third injection was given.
FERTILIZATION
After injection the fertilized egg that naturally spawned in tanks were collected with a fine dip net(100 micron mesh size). Planktonic organisms and detritus were removed by screening, unfertilized eggs settled down on bottom of tanks were removed by siphoning.
HATCHING
oThe eggs were placed in hatching containers and hatched out in about 15-20 hours.
TABLE 1.TYPE OF HORMONES, DOSAGES AND TIME INTERVALS USED FOR INDUCED SPAWNING
Treatment Hormones used
Dosage Time interval(hr)
A HCG + pituitary gland of Chinese carp
500 IU + 3 mg PG / kg
12
B HCG + pituitary gland of Chinese carp
500 IU + 3 mg PG / kg
24
C LRH-a 10ug/kg 12
D HCG + pituitary gland of Chinese carp
(1st) 500 IU + 3mg /kg (2nd) 1000 IU + 3mg PG/kg
24
TABLE 2. INDUCED SPAWNING OF GROUPER USING DIFFERENT HORMONES
Treatment
Fish number
Body weight(kg)
Time interval (hr)
Number of injections
Hormone used
Remarks
1 4.5 12 3 Partial ovulation, 12 hr after final injection. No fertilization.
2 3.6 12 3 Partial ovulation. No fertilization.
A 3 5.2 12 3 HCG500 IU+3 mg PG/kg of fish
Partial ovulation, 12 hr after final injection; fertilization rate 40%; hatching rate 20%. Larvae died after 6 days.
Treatment
Fish number
Body weight(kg)
Time interval (hr)
Number of injections
Hormone used
Remarks
4 4.8 12 2 Partial ovulation, 15 hr after final injection. Fertilization rate 30% but no hatching.
5 4.2 24 2 Ovulation 12 hr after final injection. Fertilization rate 60%; hatching rate 30%; larvae healthy.
Treatment
Fish number
Body weight(kg)
Time interval (hr)
Number of injections
Hormone used
Remarks
B 6 6.0 24 2 HCG 500 IU + 3 mg of fish
Partial ovulation. No fertilization.
7 5.8 24 2 Ovulation, 15 hr after final injection. Fertilization rate 30%; hatching rate 60%;larvae died after 10days .
C 8 4.1 12 3 Partial ovulation,15 hr after final injection. Fertilization rate 40%; hatching rate 50%; larvae healthy.
9 4.5 12 3 LRH-a 10u/kg of fish
Ovulation 12 hr after final injection. Fertilization rate 80%; hatching rate 40%;larvae healthy.
10 5.2 24 2 1st injection- HCG 500 IU + 3mg /kg of fish . 2nd injection – HCG 1000 IU + 3mg PG/kg of fish.
All fish spawned naturally 12 hr after final injection. Fertilization rate 30%; hatching rate 70%, larvae very healthy.
D 11 5.5 24 2
12 6.6 24 2
RESULTS FOR INDUCED SPAWNING
The fish under treatment D (Table 1),spawned naturally in tank 12 hours after the final injection(Table 2). Fish under treatment B (Table1) ovulated 12-15 hours after the final injection, but fertilization was completed only by artificial stripping.
Fish in treatments A and C required a third injection for ovulation, eggs were artificially fertilized 9-15 hours after the final injection.
Ovulation rate of the females treated with hormonal injections at 24-hour intervals was higher than those at 12-hour intervals(Table 2),this is due to handling that cause fish stress.
LARVAL AND FRY REARING
(Epinephelus salmoides) The larvae from hatching containers were collected
and stocked in nine 250-1 fiberglass larval rearing tanks at a stocking rate of 2500 larvae per tank.
3 types of feed were tested in 3 replicates on a completely randomized design.
o Type of feed fed to fry: 1st type- sea urchin eggs and Isochrysis; 2nd type-Isochrysis and Brachionus; 3rd type- Tetraselmis and Brachionus The larvae were reared indoor under intensive care
conditions. Beginning on day 3 feed was introduced. 20-30% of water was changed daily.
RESULTS FOR LARVAL AND FRY REARING sea urchin eggs are suitable feed for grouper
larvae, diameter of sea urchin egg was about 50ug.
Survival rate of fry fed with:• sea urchin eggs and Isochrysis from
hatching to 20 days old was 9%;• 2% for those fed with Isochrysis and
Brachionus;• none of the fry fed with Tetraselmis and
Brachionus survived; all the larvae died after a culture period of 6 days.
FINGERLING PRODUCTION
At 45 DAH-larvae have metamorphosed into juveniles ranging from 2.0-2.8cm.
5-40%-survival rates at 45 DAH. 15-25%-survival rates at density of
10larvae/L. 20,000 fingerlings-expected harvest at
density of 10 larvae/L, at 10 cubic meter tank.
batch basis –in hatchery mgt. that is each batch of larvae is treated as separate production cycle, and hatchery is shut down between each production cycle.
PROPER HANDLING PRACTICES IN HATCHERY OF GROUPER
EGG HANDLING PROCEDURES
Collection Disinfection Incubation
Characteristics of Fertilized eggs
Non-adhesive Pelagic Ranges from 0.8-0.9mm diameter
COLLECTION
Fertilized eggs are collected from the overflow of egg collector tank using fine net.
Removal from collection net once the embryo has developed optic vesicles.(i.e., at the eyed stage. However, handling eggs before this stage increases mortality and deformity.
DISINFECTION
Treated with ozone to minimize the chances of vertical transmission of VNN (Viral Nervous Nacrosis) from parent to offspring.
Ozone at concentration of 1 mg/L for 1 min. Equivalent 0.8mg/L for 1.25 minutes.
Precautionary measure should be taken when treating Ozone.
INCUBATION
After treatment, eggs are rinsed with clean and disinfected seawater.
Eggs are transferred into 0.5-1.0 cubic meters with aerated seawater.
LARVAL REARING PRACTICES AND REQUIREMENTS Larval Tanks-volume of 10cubic meter, depth of 1.2m,
color of bright yellow or pale blue to allow grouper larvae to discriminate prey more easily and tank cleaning easier, roofed, and enclosed to maintain water temp., and facilitate biosecurity. Quarantined area with entry and exit of authorized person only, disinfection of all equipments.
Aeration-provided in a grid pattern to ensure even water mixture, maintained DO levels, placed in corner to prevent stagnation, should be in the light in the early stage to prevent physical damage and could be increased if the larvae become robust.
Water-should be filtered [filtered through ultraviolet or ozone disinfection],help maintain biosecurity.
LARVAL REARING PRACTICES AND REQUIREMENTS
Sea water used must be per-treated using sand filter to remove particulates, and then sterilized to reduce potential pathogen intro.
in water. 10 larvae/L-recommended initial stocking
density for grouper. Oil-added to form thin film on water
surface(around 0.2/m L-meter square)at 1-5 DAH to prevent surface aggregation mortality in early stage.
PROBLEMS IN LARVAL REARING
Surface aggregation mortality. Larvae are attracted to patches of sunlight in
the tank hence, where that patch is present they may swim to surface of tank. Results in becoming stock in water and entangled in each other spines.
Larval mortality at first feeding.
LIVE FOODS
NUTRITIONAL ENHANCEMENT Larvae of grouper require high levels of highly
unsaturated fatty acids, EPA, ARA, DHA. Provision via incorporation in live foods.
Recommended for larvae: Artemia Brachionus Isochrysis Tetraselmis
STATUS AND TRENDS OF GROUPER IN THE PHILIPPINES
PHILIPPINES
Grouper aquaculture in the Philippines is based onthe grow-out of wild-caught fry and fingerlings.Grouper fry and fingerlings are caught using avariety of methods including hook and line, scoopor dip nets, traps, gango or fish nest, fish corral, andseveral types of nets. In the Philippines, the majorsources of grouper fry include the provinces ofPangasinan, Cavite, Mindoro, Quezon, Masbate,Bulacan, Cagayan, Dadiangas, Zamboanga del Surand Negros Oriental. The Philippines is one of thelargest suppliers of wild-caught grouper fry, fingerlingsand juveniles in Southeast Asia.
REFERENCES
Australian Center for International Agricultural Research
SEAFDEC,AQD Iloilo, Philippines Full- Cycle Aquaculture Status and
Trends
NOMU KAMSAHAMNIDA!!
DOMO ARIGATO
GOZAIMASU!!