RECENT ADVANCES IN SEED PRODUCTION OF COBIA IN INDIA.

1. SEED PRODUCTION OF COBIA
Radhakrishnan Nair
MFK1508

2. HISTORICAL BACKGROUND
• Aquaculture research with cobia was first reported in 1975 with the
collection of wild caught cobia eggs off the coast of North Carolina.
• By 1997 the technology to raise large quantities of cobia fry had been
developed.
• In the USA, the first reported captive spawning of cobia occurred in
1996 in Mississippi.
• Research on cobia was also conducted in early 1990s in Taiwan
Province of China and the technology to raise large quantities of cobia,
fry was developed in 1997.
• Between 2000 and 2006, aquaculture facilities in Virginia, Texas, South
Carolina and Florida also reported spawning cobia by either capturing
gravid females, administering hormone injection or implants, or using
photoperiod/water temperature manipulations to induce spawning.

3. RECENT ADVANCES IN INDIA
• Realising the immense aquaculture potential of Cobia in India ,
the Central Marine Fisheries Research Institute (CMFRI) has been
pursuing the broodstock development & seed production of
Cobia.
• At Mandapam regional Centre of CMFRI, success broodstock
development of Cobia had achieved on Wednesday, June 16, 2010.

4. DISTRIBUTION AND HABITAT
• Cobia are pelagic and are normally solitary except for
annual spawning aggregations;
• They will congregate at reefs, wrecks, harbours, buoys
and other structural oases.
• They may also enter estuaries and mangroves in
search of prey.
• They are found in warm-temperate to tropical waters
of the West and East Atlantic, throughout the
Caribbean and in the Indo-Pacific of India , Australia
and Japan.

5. DISTRIBUTION PATTERN

6. BIOLOGY
• They are able to tolerate a wide range of temperatures
(eurythermal) and salinity (euryhaline) between 1.6 and 32.2°C
and 5-44.5 ppt in the environment.
• Cobia prefer warm water (>20 ºC) and typically have annual
migratory patterns.
• Spawn many times from April to September, with peak in July.
• Sexual maturity -in males at 1-2 years and in females at 2-3 years
• Females grow larger and faster with maximum sizes up to 60 kg.
• Spawning occurs in both nearshore and offshore waters where
females release thousand to million eggs (1.4 mm diameter) which
are then fertilized by the males.

7. • The viable eggs begin development, are heavily pigmented, buoyant, and
hatch in approximately 24 hours.
• Cobia larvae grow rapidly and are large in comparison to most marine
species
• Juvenile fish are found in both nearshore and offshore waters, often
among weedlines where they seek shelter from predators and can feed.
• Cobia are opportunistic feeders and examinations of stomach contents
have revealed various fish, shrimp, squid, and, in particular, crabs.

8. SEXUAL DIMORPHISM
• No pronounced sexual dimorphism.
• Sexual maturity is reported in males at 1-2 years and in females 2-3
years, with females growing larger and faster with maximum size upto
60 kg (Shaffer and Nakamura, 1989).

9. PRODUCTION CYCLE

10. STAGES OF COBIA CULTURE
Brood
stock
rearing
Spawning
& egg
collection
Hatchery
production
Nursery
rearing
Grow out

11. BROOD STOCK MANAGEMENT
• Broodstock management usually includes collection, selection and
domestication of brooders as well as control of maturation,
spawning and egg collection.
• Broodstock development is mostly practised in sea cages in order to
ensure good water exchange and healthy environment. Brood fishes
can be stocked at a density of about 2 kg/m3.
• Trash fishes (sardines, scads etc.) are fed once in a day at the rate of
5% of biomass or till satiation. The trash fish has to be supplemented
with vitamins and HUFA (fish oil, squid liver oil). Broodstock nutrition
is very important and there is positive correlation between HUFA in
the broodstock diets and in the eggs and larvae.

12. • Bigger fishes of 10-15 kg weight having normal shape without any
deformity and with healthy behaviour are selected as broodstock. The
other important criteria for broodstock include bright colour and with
anus easily recognizable.
• Best temperature for maturation is around 27 ºC and the best salinity
range is 30-34 ppt.
• Separation of males and females from the broodstock cage is required
for conditioning the fish for breeding
• Cannulation can be done to assess the maturity condition of the female.
The maturation characteristics of female include egg with size above 0.7
mm, non-adhesive, white colour and round shape.
• In the case of mature males, by gently pressing the belly, the milt oozes
out

13. • Usually two males and one female are introduced to the spawning
tank. Natural spawning also can be obtained if brooders are selected
properly.
• Induction of spawning can be done by injecting LHRHa 20 μg kg-1 for
females and 10 μg kg-1 for males.
• Spawning occurs within 12-24 h after the injection.
• Egg collection can be done manually from the tank by employing 500
μm net.

14. Broodstock development and captive
breeding at Mandapam
• The wild collected cobia brood fishes (hooks and line commercial catches)
• In hatchery the fishes were treated with 100 ppm formalin (2-5 min)
• Conditioned for 2-3 days in 10 t FRP tanks before transferring to cages.
• These fishes were fed twice daily (@5% of bw) with sardines and other fish
species like Pellona and Ilisha and occasionally with squids and portunid
crabs.
• Vitamin and mineral supplements were also given twice a week along with
the feed.
• The sexes were separated by cannulation using a flexible catheter (2 mm
inner diameter) and stocked in separate cages.
• Thereafter, the females were cannulated every fortnight to assess the
diameter of the intra-ovarian eggs.

18. Induced Spawning
• Spawning can be obtained either naturally or by inducing with
hormone
• The brooders were induced for spawning with HCG at doses of 500 IU
per kg body weight for female and 250 IU per kg body weight for
males.
• The spawning occured within 36 hours after injection.
• The number of eggs spawned by cobia ranges from 0.4 to 2.5 million
• Egg collection can be done manually by employing 500 micron net.

19. • The fertilized eggs were incubated in 2 tonne capacity rectangular /
circular tanks (SD 200 to 500 eggs per litre)
• The eggs were hatched after 22 h of incubation at a temperature
range of 28-30 ºC.
• The percentage of hatching was 80%
• The newly hatched larvae measured 2.2-2.7 mm in total length

21. LARVICULTURE AND SEED PRODUCTION
• Cobia eggs are pelagic with single oil globule which is resorbed
completely at 7 dph
• Larval mouth opens at 2-3 dph (temperature dependent).
• Metamorphosis starts from 9-11 dph.

22. Stage of Larvae
(dph)
3 dhp – 10 dhp • The enriched rotifer (Brachionus rotundiformis) @ 10-12 nos./ml, four times a
day
• Rotifers enriched with DHA SELCO at a density of 6-8 nos./ml
8 dhp - 10 dph • enriched Artemia nauplii @ 1-3 nos./ ml, 4-6 times per day.
10 dph – 18 dph • During the rotifer and Artemia feeding stage, green water technique is used in
the larviculture system with the microalgae Nanochloropsis oculata at a cell
density of 1x105 cells/ml.
18 dph – 25 dph • Weaning to artificial larval diets. While weaning, formulated feed has to be fed
30 min before feeding with live feeds.
• Continuous water exchange is required during weaning.
25 dph -40 dph • the larvae are highly cannibalistic and hence size-grading is undertaken every
four days to one week.
• fry could be weaned totally to artificial diets

23. feeds was also started as per details given below:

24. • The juveniles measuring 10 cm (30 dph) length were ready for
stocking in hapas
• All the fingerlings of 10 cm length and above were stocked in hapas in
the sea for nursery rearing for about a month before transferring
them to the grow-out cages.

28. NURSERY REARING
FIRST PHASE
• 0.2 - 2g to 5g fry grow rapidly to fingerlings
• Size 8-10 cm (20 to 45 dph)
SECOND PHASE
• 2 -5 to 30 g (45 to 75 dph)
• In large ponds with green water or in hapas in the sea.
• Artificial feed are provided manually to satiation, 5 to 6 times daily.
• grading should be undertaken
THE THIRD PHASE
• 30 to 600 - 1000 g (75-150 dph to 180 dph).
• Grading is undertaken only once during this stage
Nursery rearing of cobia generally comprises three phases.

29. GROW-OUT FARMING
• Cobia is cultured in offshore grow-out cages until they reach
marketable size. Culture period ranges between 6-8 months.
• Small scale family owned cage farms and commercial cage farms are
employed for cobia grow-out farming. Usually most of the cagefarms
integrate nursery and grow-out culture in one area for convenient
transfer of fish stock from nursery to grow-out cages.
• Sinking and floating pellet feeds are used in grow-out cages.

30. SEA CAGES.
Norwegian type sea cage.Taiwanese type sea cage.

31. ENVIRONMENTAL FACTORS
DO - >5mg/l,
NH3 - <0.1mg/l,
pH - 7.8-8.4,
Salinity - 25-35ppt,
Temperature - 24-330C

32. NUTRITIONAL ASPECTS
JUVENILES
Protein 45%
Lipid 5-10%
Vitamin& minerals No information
Asian seabass or grouper feeds are accepted
FCR 1.5-1.8

33. DISEASES AND CONTROL MEASURES
DISEASE AGENT TYPE SYNDROME MEASURES
Marine velvet
disease;
Amyloodiniosis
Amyloodinium
ocellatum
Parasitic
dinoflagellate
Coughing; flashing;
operculum flared out;
reluctance to feed;
visible on gills & fins;
appears as small dark
spots on gill filaments
under a stereoscope
Copper sulphate
pentahydrate; decrease
salinity in some cases
(freshwater dip); flush
system; formalin
bath/treatment;
mechanical filtration
down to at least 40
microns
Cryptocaryonosis;
marine white spot
Cryptocaryon
irritans
External protozoan
White foci visible on
skin; interconnected,
larger masses of
whitish spots
Prolonged copper
immersion; freshwater
dips; formalin treatment;
decrease salinity to 15 ‰
or less for 2 weeks;
decrease system
temperature to <19 ºC

34. Sessile, colonial,
ciliate infestation
Epistylis spp. Stalked ciliate
Reported during larval stage; white
or reddish masses on the skin/fins,
gill arches, or in mouth; more
common in polluted waters; often
associated with gram-negative
bacterial condition called red sore
disease
Formalin treatment;
freshwater bath/dip;
antibiotics for severe
bacterial infection
Trichodinosis Trichodina sp.
Protozoan
parasite
Reported during nursery stage;
found on skin & gills; loss of
appetite; lethargy; chronic low level
mortality; often leads to secondary
infections
Formalin treatment;
freshwater bath;
copper treatment;
Praziquantel bath or
prolonged immersion
Monogenean
infestation
Neobenedenia
sp.
Monogenean
flatworm
parasite
Reported during grow-out stage;
skin damage & ulceration; eroded
fins; eye lesions which can lead to
blindness
Formalin treatment;
freshwater bath;
copper treatment;
Praziquantel bath or
prolonged immersion

35. Myxidiosis
Sphaerospora-like
myxosporidean
Myxosporidian
parasite
Poor appetite &
ascites; enlarged
kidney exhibiting
patches or nodules;
skin ulcers; spores in
the digestive tract
No known treatment;
disinfect system;
quarantine affected
fish
Coccidiosis Coccidia spp. Protozoan parasite
Abdominal swelling;
exopthalamy; cysts in
liver tissue; varies with
organ affected
Treat fish with oral
monensin; reduce
stress
Lymphocystis Iridovirus Virus
Reported during
nursery stage; skin,
fins & gills with white,
bumpy growths
No known treatment;
disinfect system;
quarantine fish

36. Pasteurellosis
Photobacterium
damsela subsp.
Piscicida
Bacterium
Whitish,
granulomatous
deposits on kidney,
liver & spleen
None known but
vaccine being
developed
Vibriosis
Vibrio alginolyticus; V.
vulnificus & V.
parahaemolyticus
Bacteria
Swollen abdomen;
skin ulcers; protruded
eyes; lethargy;
darkening of skin;
ascites in peritoneal
cavity
Administer antibiotics;
remove diseased fish;
disinfect system;
reduce stress
Secondary bacterial
infection (after
Neobenedenia
infestation)
Streptococcus sp. Bacterium
Can cause blindness in
cobia; protruded eyes;
skin ulcers; skin
darkening
Administer antibiotics;
remove diseased fish;
disinfect system;
reduce stress

37. Recent success in Mandapam Regional Centre of
CMFRI
Volitional spawning of cobia in RCC tanks
– spawned volitionally without any hormonal induction during the
month of May 2013.
– The water quality parameters were maintained at highest standards
with indigenously designed filtration systems.
– A total of 2.5 million fertilized eggs were obtained and 85 % hatching
was achieved in the volitional spawning.

38. First successful spawning of cobia in RAS
– Was achieved at Mandapam on 20th September 2013.
– The total number of eggs spawned was 2.40 million and the
fertilization percentage was 86.1.
– The temperature range was 27.5 – 29°C
The first successful off-season spawning of cobia
– through thermal regulation has been achieved in the RAS on 02nd
December 2013.
– Temperature was raised in the RAS to 29.7 to 30.3 °C, by titanium
heaters.
– Hormonal induction with hCG was done

40. PASSIVE INTEGRATED TRANSPORDER (PIT)
• The brood fishes were sexed and tagged with Passive Integrated
Transponder (PIT) tags in order to maintain the breeding
history.
• The PIT tag is a device to permanently mark fishes internally
with radio frequency tags.

42. , 43395
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
50000
1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
TONNES
GLOBAL PRODUCTION OF COBIA
SOURCE:-http://www.fao.org/fishery/culturedspecies/Rachycentron_canadum/en
Production trends
1997- 9 tonnes
2013- 43395 tonnes

43. • Of the production reported to FAO in 2004, 80.6 percent was
produced in China and all the rest in Taiwan Province of China.
The total value of the global production of this species in 2004
was USD 36206000.
• Cobia aquaculture production has been steadily expanding in
Asia, primarily in Taiwan, Vietnam and China, but also in other
Southeast and Indo-Pacific Asian countries including the
Philippines, Indonesia, Iran and Reunion Island.

44. CONCLUSION
• Cobia, a fast growing potential marine candidate species for the future,
which has already been gaining momentum in China, Taiwan, Indonesia,
USA, Vietnam, Australia, etc. could be developed for culture in India.
• Encourages more farmers to undertake cobia culture (hatchery and
farming) for livelihood support.
• 20% of the currently unutilized shrimp farms could be converted into
productive cobia farms with minimum investment.
• Effective utilization of near shore waters for cobia farming in floating cages.
• Innovative value added fish products will be introduced in domestic and
export markets.
• Technologies developed would be transmitted to the fisherfolk to raise
their income through cobia culture.

45. REFRENCES
• Successful seed production of cobia Rachycentron canadum and its prospects for
farming in India. G. Gopakumar
Marine Fisheries Information Service T&E Ser., No. 206, 2010
• Major achievements of research
MD/IDP/03 - Broodstock development, captive breeding and seed
productiontechniques for selected marine finfishes and ornamental fishes (2009-2012)
(AND)
FISHCMFRISIL201202400024 - Development and standardization of seed production
technologies for selected high value finfishes and shellfishes (2012-2014)
• Broodstock development & seed production of cobia rachycentron canadum
Dr. A. Gopalakrishnan
• http://www.thefishsite.com/articles/1234/seed-production-of-cobia-in-india/
• http://eprints.cmfri.org.in/8456/
• http://www.fao.org/fishery/culturedspecies/Rachycentron_canadum/en