Cultivable brachish water fishes

Cultivable  brachish water fishes

Brackish water fish farming is a system of aquaculture that focuses on
theproduction of quality fin and shell fish that are found in the creeks,
lagoons, andestuaries. In India, traditional system of brackishwater
aquaculture is in vogue since timeimmemorial in West Bengal (Bheris) and Kerala
(Pokkalifields).

Cultivable Brackishwater Fin fishes Grey mullet (Mugil cephalus) Milk fish
(Chanos chanos) Pearl spot (Etroplus suratensis )

1. Mugil Cephalus (Grey Mullet
పరగలు)

· Most mullets reach about 8 inches (20 centimeters) in total length, but
some may be as long as 31 to 39 inches (80 to 100 centimeters).

· Body cilindrical, robust. Head broad

· Colour back blue/green, flanks and belly pale or silvery; scales on back
and flanks usually streaked to form longitudinal stripes.

· It is widely distributed in brackish waters. It has
distinct greenish colour of the body

· It feeds on filamentous and
planktonic algae, vegetable debris and mud at the bottom in
shallow waters. It grows to about three feet in length.

· In India mullets are cultured in combination with milk
fish,pearlspot and other estuarine species.

· Fast growing, tolerates a
wide range of temperature, oxygen and salinity.

· 

· Mullet reaches around 100g in wt in about 4 months &
about 200g by the end of year.

Chanos Chanos (Milk
fish or Pala Bontha)

· Body fusiform, elongated,
moderately compressed, smooth and streamlined.

· Body colour silvery on
belly and sides grading to olive-green or blue on back.

· Dorsal, anal and caudal fins
pale or yellowish with dark margins. Single dorsal fin with 2 spines and 13-17
soft rays

· 

· It grows to about four feet
in length.

· In India, Chanos fry are collected and stocked.

· The Chanos is plankton feeder and feeds mainly on
filamentous green algae. Lakhs of fry are caught in tidal creeks with peak
period of availability in April, May and June.

· The chanos grow quicker in fresh water
(25 inches) than in brackish water (19 inches).

· Milk fish are usually cultured in Pens. 

· The survival rates ranges from 80 to 95% amounting to a production ranging
from 500 to 1000 kg/ha in ponds and 250 to 500 kg/ha in pens.

Pearl spot
(Etroplus suratensis)

· Body is deep, short, oval
and strongly compressed laterally. 

· Eyes large, mouth small and
terminal.

· Body is ligt greenish with
eight yellowish oblique bands.

· Pearl spot(Etroplus
suratensis) These are Cultured in both brackishwater and freshwater
environments.

·  Though growth is slow, at a high stocking
density table-size fish can be harvested in 9-12 months culture period.

· Seed is produced through
induced breeding.

· Pearl spot fishes are
usually stocked @ 5000/ha

· The culture of pearlspot is
more economical under polyculture system especially with milkfish and mullets
than under monoculture

· The fish can attain a marketable
size of 120-150 g over a period of 8-10 months.• Though growth rate is
relatively slow, high stocking density with low input management can yield
optimum production.

Lates calcarifer

· Body oblong—elongate,
compressed, with a deep caudal peduncle.

· Head pointed, with concave
dorsal profile becoming convex in front of dorsal fin.

· Mouth large, slightly
oblique; lower jaw projecting, upper jaw reaching to behind eye.

· Dorsal and anal have scaly
sheaths, anal fin round with 3 spines and 7–8 soft rays; caudal fin round.
Scales large, ctenoid.

· Colour: adult with olive
brown sides and a silvery belly; juvenile stage, body with 3–4 black transverse
bars and disappear when the fish grow to adult.

· The adult fish is regarded as carnivorous,
but juveniles are omnivorous

· Cage based  Seabass culture models were developed by
Gujarath

· Chennai has successfully
demonstrated cage farming of Lates calcarifer

· were grown to a marketable
size of 900 g - 1.25 kg in 6 months