BArramundi azmir

8/3/2019 BArramundi azmir

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SHN 3113

Lab 2: Aquaculture species (2)

Learning Objective

1. To learn in details about aquaculture species locally and globally

2. To determine the latest research about aquaculture species

Materials and Methods

Group discussion and presentation

Instructions

1. Every group will receive one aquaculture species

2. Write a report about the species and present in front of the class. Please

submit the report in the following week and presentation will be held in week

10 or 11.

3. In the report, you must include all the following details:

a. The most cultured species under the same genus or family. Describe

each species in details

b. Include the biology, production locally and globally, feeding habit,

natural spawning or artificial fertilization and general characteristic

c. Discuss about the aquaculture system normally use to culture the

species

d. Find an interesting facts or research related to your species and

describe about it

e. Briefly discuss about the challenges facing by the aquaculturist in

producing the species.


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Barramundi (Lates calcarifer)

Introduction

Seabass, Lates calcarifer, is an economically important food fish in tropical countries. It is a

species with catadromous habits within its areas of distribution. Studies on the biology and

fisheries of the species are still in progress but the possibility of its culture has been

established and undergoing development. This species categorized in kingdom animalia,

phylum chordata, class actinoptergyii, perciformes, family latidae, genus lates.

Biology and life history

The barramundi (can live in fresh, brackish and marine environments) and

catadromous (grows to maturity in fresh or brackish waters and spawns in the sea)

characteristics of the species result in a very interesting ecological distribution at various

stages of its life history. The fish spend most of their life in a lagoon which connects to the

sea. They spend two to three more years in estuarine areas until they mature, then migrate

to the sea water around the mouth of a river or lagoon for spawning. Larvae and juveniles

live in the sea grass bed in coastal areas for about six months, attaining a size of about 2 to


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5 inches. The fish migrate to freshwater when they grow bigger. Spawners live in coastal

rocky shores but some migrate to a freshwater body after the spawning is over.This species

has an elongate body form with a large, slightly oblique mouth and an upper jaw extending

behind the eye. the lower edge of the preoperculum is serrated with a strong spine at its

angle; the operculum has a small spine and a serrated flap above the origin of the lateral

line. Its scales are ctenoid. In cross section, the fish is compressed and the dorsal head

profile clearly concave. The single dorsal and ventral fins have spines and soft rays; the

paired pectoral and pelvic fins have soft rays only; and the caudal fin has soft rays and is

truncate and rounded. Barramundi are a salt and freshwater sportfish, targeted by many.

They have large silver scales, which may become darker or lighter, depending on their

environment. Their bodies can reach up to 1.8 meters (5.91 feet) long, though evidence of

them being caught at this size is scarce.

Feeding habit

The adult fish is regarded as carnivorous, but juveniles are omnivorous. Analysis of stomach

content of wild seabass (1 to 10 cm) found 20 % phytoplankton and the rest are small fish

and shrimp. The larger fish consists of 100 % animal prey, 70 % crustacean and 30 % small

fish. Barramundi are euryhaline, but stenothermal. This catadromous species inhabits rivers

and descends to estuaries and tidal flats to spawn. In areas remote from freshwater purely

marine populations may become established. At the start of the monsoon, males migrate

downriver to meet females, which lay very large numbers of eggs (multiple millions each).

The adults do not guard the eggs or the fry, which require brackish water to develop.

Production locally and globally

The fish is of large commercial importance.It is fished internationally and raised in

aquaculture in Australia, Malaysia, India, Indonesia, Israel, Thailand, the United States and

Poland. The Australian barramundi industry is relatively established with an annual

production of more than 4000 tons. In the broader Southeast Asian region production is

estimated to exceed 30,000 tons. By contrast, the US industry produces about 800 tons a

year from a single facility. Barramundi under culture will commonly grow from an ex-hatchery

juvenile, between 50 and 100 mm in length to a table size of 400-600g within 12 months and

to 3.0 kg within 1824 months. In the Asian Pacific region, Malaysia, Indonesia, Taiwan and
http://en.wikipedia.org/w/index.php?title=Preoperculum&action=edit&redlink=1http://en.wikipedia.org/wiki/Operculum_%28fish%29http://en.wikipedia.org/wiki/Ctenoidhttp://en.wikipedia.org/w/index.php?title=Compression_%28zoology%29&action=edit&redlink=1http://en.wikipedia.org/wiki/Dorsal_finhttp://en.wikipedia.org/wiki/Ventralhttp://en.wikipedia.org/wiki/Fin_rayhttp://en.wikipedia.org/wiki/Pectoral_finhttp://en.wikipedia.org/wiki/Pelvichttp://en.wikipedia.org/wiki/Fin_rayhttp://en.wikipedia.org/wiki/Caudalhttp://en.wikipedia.org/wiki/Fin_rayhttp://en.wikipedia.org/wiki/Truncatehttp://en.wikipedia.org/wiki/Euryhalinehttp://en.wikipedia.org/wiki/Stenothermichttp://en.wikipedia.org/wiki/Fish_migrationhttp://en.wikipedia.org/wiki/Estuaryhttp://en.wikipedia.org/wiki/Mudflathttp://en.wikipedia.org/wiki/Oceanhttp://en.wikipedia.org/wiki/Monsoonhttp://en.wikipedia.org/wiki/Brackish_waterhttp://en.wikipedia.org/wiki/Aquaculturehttp://en.wikipedia.org/wiki/Malaysiahttp://en.wikipedia.org/wiki/Indonesiahttp://en.wikipedia.org/wiki/Agriculture_in_Israel#Fishing_having_a_barra_and_aquaculturehttp://en.wikipedia.org/wiki/Thailandhttp://en.wikipedia.org/wiki/Thailandhttp://en.wikipedia.org/wiki/Agriculture_in_Israel#Fishing_having_a_barra_and_aquaculturehttp://en.wikipedia.org/wiki/Indonesiahttp://en.wikipedia.org/wiki/Malaysiahttp://en.wikipedia.org/wiki/Aquaculturehttp://en.wikipedia.org/wiki/Brackish_waterhttp://en.wikipedia.org/wiki/Monsoonhttp://en.wikipedia.org/wiki/Oceanhttp://en.wikipedia.org/wiki/Mudflathttp://en.wikipedia.org/wiki/Estuaryhttp://en.wikipedia.org/wiki/Fish_migrationhttp://en.wikipedia.org/wiki/Stenothermichttp://en.wikipedia.org/wiki/Euryhalinehttp://en.wikipedia.org/wiki/Truncatehttp://en.wikipedia.org/wiki/Fin_rayhttp://en.wikipedia.org/wiki/Caudalhttp://en.wikipedia.org/wiki/Fin_rayhttp://en.wikipedia.org/wiki/Pelvichttp://en.wikipedia.org/wiki/Pectoral_finhttp://en.wikipedia.org/wiki/Fin_rayhttp://en.wikipedia.org/wiki/Ventralhttp://en.wikipedia.org/wiki/Dorsal_finhttp://en.wikipedia.org/w/index.php?title=Compression_%28zoology%29&action=edit&redlink=1http://en.wikipedia.org/wiki/Ctenoidhttp://en.wikipedia.org/wiki/Operculum_%28fish%29http://en.wikipedia.org/w/index.php?title=Preoperculum&action=edit&redlink=1


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Thailand remain the leading countries involved in commercial sea bass production, with

Hong Kong.

Farming system

Criteria for selecting a suitable site for cage culture of seabass are the following:

1. Water salinity (which should range from 1031 ppt).

2. Tide and water depth. Water depth should be more than 23 meters. This is due to

the usual size of culture cage which is 5 m 5 m and 2 m deep. The tidal fluctuuation

should allow the water depth to be at least 2 meters at the low water of spring tide.

3. Current and waves. Area should be protected from strong winds, waves and current.

An ideal area would be in protected bays, sheltered coves and inland sea.4. Water quality. The site should be relatively free from domestic, industrial and

agricultural wastes and other environmental hazards.

5. Water circulation. The site should have enough water circulation to improve on poor

water quality that could occur at some period in the culture due to the decomposition

of waste material which often accummulate at the bottom under the net cage.

In concrete tanks also can be as a suitable system for seabass,depending upon the

production target, the number and size of the fishes proposed to be maintained broodstock

holding tanks are constructed . It is advisable to maintain fishes in large tanks because the

fish will have more natural condition and sufficient space will be there for swimming. Brood

stock tanks of 144 meter per cube are used. Broodstock tanks should have adequate water

inlet and drainage provision. Flow through facility is desirable and provision for aeration is

adviseable. The concrete tanks can be covered with shade nets to prevent the direct sunlight

exposure to the tanks. Cannibalism is one of the serious problems encountered during early

stages of sea bass culture. This may be related to the uniform size of the fry and heavy

stocking density.


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Floating cage

The net cages are hung on GI pipe, wooden or bamboo frames. The cage is kept afloat by

styrofoam drum, plastic carbuoy or bamboo. The most convenient dimension for a cage is

that of a rectangle and a volume of 50 cubic meters (5.5 m 6 m 2 m). The cage unit is

stabilized with concrete weights at each bottom corner (Figure 2). The cage unit has to be

anchored to the bottom. The cages might be rocked a little by strong wind and current.

Floating cages can be set on coastal waters where tidal fluctuation is wide.

Stationary cage

This type is fastened to wooden poles installed at its four corners . Stationary cages are

usually set in shallow bays where the tidal fluctuation is narrow.


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The mesh size of nylon net would depend on the size of fish as shown in. Firstly,

finglerlings should be transferred to a nylon net (mesh size of 2.0 cm) for about 2 months

of culture period. Them they are moved to a cage net of 4.0 cm mesh size until harvest.

* The cages should be checked bimonthly or monthly to ensure that they are not

damaged by fouling organisms, crabs or flotsam. The cages should be cleaned or

changed every month. Therefore, fish farmers should have spare nylon net cages.

Changing cages also allows the farmer to check on the number and health of the fish.

Interesting facts about barramundi

The species is sequentially hermaphroditic, most individuals maturing as males and

becoming female after at least one spawning season. Most of the larger specimens are

therefore female. Fish held in captivity sometimes demonstrate features atypical of f ish in the

wild: they change sex at a smaller size, exhibit a higher proportion of protogyny and some

males do not undergo sexual inversion. Smaller specimens are a popular aquarium fish and

can be very entertaining especially at feeding time. However they grow quickly, so it is not

recommended that they be kept in any set up of less than 5 feet ( 500 litres) In aquaria they

become quite tame and can be hand fed, they are non aggressive species however the

feeding reflex is violent and sudden so they cannot be kept with any tank mates small

enough to be swallowed. Sea bass has been cultivated in both brackish water and

freshwater ponds as well as in marine cages. A relatively high dietry protein level may be

suggested for sea bass since the fish is primarily a carnivore under natural conditions. Dietry

crude protein(cp) requirement of juvenile sea bass to be 50%. The highest growth was

achieved with a dietry level of 45% . The essential amino acid requirement of sea bass.

Where, tryptophan requirement of juvenile sea bass to be 0.5% of dietry protein. The

requirement for methionine, lysineand arginine have been determined to be 2.24, 4.5 -5.2

and 3.8% of dietry protein, respectively. But excessive concentration of tyrosine in the sea

bass diet may result in kidney malfunction. The optimum dietry lipid level for sea bass

fingerlings is between 15 and 18% found that when -62 g sea bass were fed diets containing

9.3 % and 12.9% fat, growth was similar but the FCR was significantly lower with the 12.9%

fat diet. The growth and survival of sea bass fry fed a diet containing 9% supplemented lipid

comprising 4.5% cod liver oil and 4.5% soybean oil were higher compared with those fed

cod liver oil alone or soybean oil alone. In addition, the performance of the fry decreased

when these dietry lipid sources were replaced with coconut oil and the poorest performance

when diet contained no lipid supplement..
http://en.wikipedia.org/wiki/Hermaphroditehttp://en.wikipedia.org/wiki/Protogynyhttp://en.wikipedia.org/wiki/Sexual_inversionhttp://en.wikipedia.org/wiki/Sexual_inversionhttp://en.wikipedia.org/wiki/Protogynyhttp://en.wikipedia.org/wiki/Hermaphrodite


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The challenges in culture of barramundi

Environmental impacts associated with marine fish cage aquaculture derive mainly fromnutrient inputs from uneaten fish feed and fish wastes. For example, studies carried out in

Hong Kong indicate that 85 percent of phosphorus, 8088 percent of carbon and 5295

percent of nitrogen inputs (from 'trash' fish) to marine finfish cages may be lost through

uneaten food, faecal and urinary wastes. These nutrient inputs, although small in

comparison with other coastal discharges, may lead to localised water quality degradation

and sediment accumulation. In severe cases, this 'self pollution' can lead to cage farms

exceeding the capacity of the local environment to provide inputs (such as dissolved oxygen)

and assimilate wastes, contributing to fish disease outbreaks and undermining

sustainability.


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White Seabass, Atractoscion nobilis

Kingdom:AnimaliaPhylum:Chordata

Class:Actinopterygii

Order:Perciformes

Family:Sciaenidae

Genus:Atractoscion

Species:Atractoscion nobilis

Biology:

The white seabass is the largest of the 10 species in the family Sciaenidae

(croakers and drums) known to occur in California coastal waters, and can reach a

size of up to 5 feet and about 95 pounds (Miller and Lea 1972).

White seabass are broadcast spawners, with multiple (2-5) males simultaneouslyreleasing gametes to fertilize the eggs of a spawning female within the water column

(Aalbers and Drawbridge, in press). The spawning activity of white seabass occurs

from March through July and peaks in May, with the majority of spawning events

occurring over the two hour period following sunset. A nighttime spawning strategy is

typical of other temperate croakers, and has likely been adopted to reduce initial egg

predation (Holt 1985).


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Like most croakers, male white seabass produce sounds by contracting

specialized sonic musculature to resonate low frequency sound off of the adjacent

swim bladder. As is the case in most croaker species, female white seabass lack

this specialized structure (Tavolga 1964). Sound production has been associated

with reproduction in other sciaenid species, including the red drum Sciaenops

ocellata (Guest and Lasswell 1978) spotted seatrout Cynoscion nebulosis (Mok

and Gilmore 1983), weakfish Cynoscion regalis(Connaughton and Taylor 1995)

and orange-mouth corvina Cynoscion xanthulus (Fish and Cummings

1972). Numerous fish species have developed effective sound producing and

detection mechanisms to take advantage of the high speed and distance of sound

propagation underwater (Hawkins and Myrberg 1983). Sound production

apparently supports the development of spawning aggregations and may aid in

the simultaneous release of gametes during broadcast spawning events after

dark.

Production locally and globally:

Commercial landings of white seabass have fluctuated widely over the nearly85 years of record keeping. Almost three million pounds were reported in 1922,

599,000 in 1937, 3.5 million in 1959, and 58,000 in 1997. Since 1959 the trend has

been one of decline, although landings have been over 100,000 pounds for the years

1984 through 1991 and 1998-1999. Although there was a commercial fishery in the

San Francisco area from the late 1800s to the mid- 1920s, landings of fish caught

north of Point Conception rarely exceeded 20 percent of the total California catch.

Today, catches of white seabass are concentrated along the coast from PointConception to San Diego and around the Channel Islands. The frequency of fish

caught north of Point Conception has increased in the past few years, although the

pounds landed still represent less than 20 percent of the total California catch.

Before 1982, California commercial fishermen landed thousands of pounds of white

seabass taken in Mexico. Often these landings comprised more than 80 percent of

the annual catch. Since then, the Mexican government has denied access permits to

U.S. fishermen, and the fishery is concentrated in California. During the early years

of the fishery, commercial catches were made using gillnets, hook-and-line, and


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round haul nets such as lamparas and purse seines. Purse seining was curtailed in

the late 1920s because decreasing catches made it uneconomical. Since all round

haul nets were prohibited in the early 1940s, gillnets have been the major

commercial fishing gear. Set gillnet fishing for white seabass within state waters was

completely disallowed beginning in 1994. Therefore, drift gillnetting is the primary

fishing method utilized today. Some commercial hook-andline fishing takes place

during the early spring, when large seabass are available. Although the legal size

limit for white seabass is 28 inches (about seven pounds), the average commercially

caught fish is nearly 40 inches (about 20 pounds). Because of consumer demand,

seabass has always commanded relatively high prices. In 2000, commercial

fishermen were typically paid $2.25 per pound for whole fish. At the retail level the

fish are sold fresh, primarily as fillets and steaks. Recreational fishing for white

seabass began around the turn of the century. Because of their size and elusive

nature, seabass are popular with anglers. Historical records show that anglers on

commercial passenger fishing vessels (CPFVs), fishing in California waters, landed

an average of 33,400 fish annually from 1947 through 1959. The catch steadily

declined to an average of 10,400 fish in the 1960s, 3,400 fish in the 1970s, and

1,200 fish in the 1980s, but increased to 3,000 fish in the 1990s. In fact, the 1999

recreational catch of white seabass from California waters was greater than 11,000

fish and appears to be as high for 2000. Additional seabass are caught by anglers

aboard private boats, but accurate catches by private boat anglers are difficult to

estimate. Today, sport anglers catch white seabass that are generally between

seven and 25 pounds. This was not true in the past. While the 28-inch size limit also

applies to recreational anglers, most of the catch prior to the 1990s (kept and

released) was between 20 and 24 inches. In a survey of private boaters at launch

ramp facilities from 1978 through 1982, biologists found that only six to 16 percent of

the white seabass kept were of legal size. In a similar survey aboard CPFVs from

1985 through 1987, biologists reported that 16 to 25 percent of the seabass caught

were legal. However, this has changed dramatically with the apparent increase in the

abundance of legal-size white seabass. During the period from 1995 through 1999,

data collected from private boat anglers revealed 77 percent of the fish were legal

size while data from CPFV anglers showed 80 percent of the fish were legal size.

White seabass are more often caught with live bait than with dead bait or lures, butall are effective when the fish are actively feeding. Seabass can sometimes be


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brought to the surface by heavy chumming with live bait. Anglers fishing around

Santa Catalina Island have reported consistently good catches using blacksmith and

silversides as bait. However, when available, live squid and Pacific sardines are

popular baits. Spearfishing for large seabass by free divers (without SCUBA) is

successful in kelp beds. Regulations covering white seabass have been in effect

since 1931, and have included a minimum size limit, closed seasons, bag limits, and

fishing gear restrictions. Such regulations are in effect today, w White Seabass shery

management plan for white seabass is presently being adopted and the need for

additional regulations will be considered.

Natural spawning or artificial fertilization:

Biologists believe the movement is probably spawning-related. Spawning

occurs from April to August, with a peak in the late spring to early summer. Fecundity

(egg productivity) for this species has not been determined, but a maturity study in

the late 1920s reported that females begin maturing when four years old (nearly 24

inches), and some males were sexually mature at three years (20 inches). All white

seabass have probably spawned at least once by age six (nearly 32 inches). Theeggs, which are the largest of any croaker on the west coast (approximately 0.05

inch in diameter), are planktonic. The larvae, which are darkly colored, have been

collected from Santa Rosa Island, California to Magdelena Bay, Baja California. Most

are found in the inshore areas of Sebastian Viscaino and San Juanico Bays, Baja

California, indicating that major spawning occurs off central Baja California. Young

of-the-year white seabass, ranging in length from 0.25 inch to 2.25 inches, inhabit

the open coast in waters 12 to 30 feet deep. They associate with bits and pieces of

drifting algae in areas of sandy ocean bottom. Sometime between the ages of one

and three years old, they move into protected bays where they utilize eelgrass

communities for cover and forage. Older juveniles are caught off piers and jetties

and around beds of giant kelp. Adult seabass occupy a wide range of habitats

including kelp beds, reefs, offshore banks, and the open ocean. Adult white seabass

eat Pacific mackerel, Pacific sardines, squid, pelagic red crabs, and Pacific herring.

Laboratory spawning of white seabass was first induced in 1982. Beginning in 1983,

the California Department of Fish and Game initiated the Ocean Resources


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Enhancement and Hatchery Program (OREHP) to test the feasibility of raising

seabass for population enhancement. That goal was achieved in the first 10 years of

the program and the goals of the program have been expanded to test the feasibility

of enhancing marine fish populations through the stocking of cultured fish. By 1999,

more than 375,000 juvenile. White seabass had been released off southern

California, and it is estimated that 17,500 of those may have survived to legal size or

larger. Additionally, valuable life history information has been gathered during this

program through ecological surveys, tagging, and genetic studies. However, more

work is necessary to determine if artificial propagation is successful in enhancing the

seabass population.

General characteristics:

The body of the white sea bass is elongate, and somewhat compressed. The

head is pointed and slightly compressed. The mouth is large, with a row of small

teeth in the roof; While the lower jaw is slightly projected. The color is bluish to gray

above, with dark speckling, becoming silver below. The young have several dark

vertical bars that fade as the white sea bass reaches maturity. The white sea bass isclosely related to the California corbina, but is the only California member of the

croaker family to exceed 20 pounds in weight. They are most easily separated from

other croakers by the presence of a ridge running the length of the belly. White

seabass are the largest members of the croaker family on the U. S. Pacific coast,

reaching a maximum recorded length of 1.5 m and 41 kg and twenty years in age.

Aquaculture system normally used to culture White Seabass.

Phase 1. Seabass fry (15-21 days old) can be reared in earthen ponds, land-

based tanks, or in net cages (hapa) set in ponds. Ponds are preferably not more

than 2,000 m2 for easy management. Ponds are prepared and fertilized at least one

week before stocking to eradicate predators and grow zooplankton. This phase can

take 10-20 days. Fish are harvested when size is 2.5 cm total length. Concrete

nursery tanks are 3-5 tons where fry can be weaned to formulated diet. They are fed


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every 2 hours, size-graded every 5-7 days, and harvested or transferred at 2.5-3.0

cm total length. This can take 30 days. Net cages (hapa) set in ponds can measure 2

x 1 x 1 m. Optimum stocking density is 150-200 fry/m3. Fry are fed with natural

zooplankton, mysids, mosquito larvae and/or formulated diet, graded every 5-7 days,

and harvested or transferred to B-net when the fry attains 2.5-3.0 cm total length.

This can take 30 days. Lights can be provided to attract zooplankton and encourage

fish foraging during the night.

Phase 2. At this stage, fish juveniles are fed trash fish or formulated diet 6x

per day until they reach 20-50 g, the ideal size for grow-out culture. Phase 2 nursery

can be done in concrete tanks or cages in ponds. In concrete tanks (3-5 tons),

juveniles are fed with formulated diet every 2 hours. Juveniles are graded and the

tanks cleaned every 5-7 days. In ponds, B-net cages can measure 2 x 3 x 1 m or 1 x

3 x 1 m. The same procedure is used as in the above and the fish are harvested at

7-10 cm total length.

Seabass juveniles are stocked at about 20-50 g average body weight. They

are fed fish by-catch at 5-10% biomass or formulated diet at 3-5% biomass given 2-

3x per day. Seabass can reach marketable size of 300-600 g in about 4-7 months.

Grow-out culture can be done in ponds or cages. Pond culture. The recommended

stocking density is 5,000 pcs/ha. Water is changed at 40-60% of volume daily during

spring tide. Cage culture. Cage size is 5 x 5 x 3 m with a recommended stocking

density of 15-20 pcs/m3.

Other interesting issues:

There is an exciting and unique program in southern California working to

help restore and rehabilitate some of our depleted marine fisheries. The Ocean

Resources Enhancement Hatchery Program (OREHP) was instituted through

legislation in 1983 and is administered by the California Department of Fish and

Game. Lead by a research team from Hubbs-SeaWorld Research Institute, and

support from many others, an experimental marine fish hatchery was built on the

Agua Hedionda Lagoon in Carlsbad, California in 1995. The hatchery represents a


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unique facility that blends mariculture with scientific research toward the goal of not

only improving the depleted fisheries in southern California, but also of increasing

our knowledge of these species and their life histories. Although the hatchery is

located in San Diego County, satellite growout facilities and program supporters

extend throughout southern California. Once the cultured white seabass reach a

fingerling size of 3 4 inches, they are tagged and transported to one of twelve

growout facilities located up and down out coastline. Volunteer groups, coordinated

by the United Anglers, operate each of these facilities and include local angling

clubs, research organizations, and environmental groups. Volunteers care for the

juvenile fish until they reach a size of 8 12 inches, when they are released into the

ocean, with the hope that they will survive and contribute to the wild seabass

population. Presently growout facilities exist in San Diego Harbor, Mission Bay, Dana

Point Harbor, Newport Harbor, Huntington Harbor, King Harbor, Marina del Rey, Port

Hueneme, Channel Islands Harbor, Santa Barbara, and Catalina. Each white

seabass is identified with a small coded wire tag that is inserted into the cheek

muscle of the fish. These tags hold a unique batch code that allows every seabass to

be identified with the specific group that it was released with. Later when a tag is

recovered, it is possible to determine where and when the fish was released, and

how far it had traveled. Most importantly, researchers are using these tags to assess

survivorship and to optimize the conditions under which fish are released. It is

impossible to differentiate a wild white seabass from one that has been raised at the

hatchery externally since the tags are internal. Specialized wands are used to scan

seabass to determine whether or not they are tagged. This is another area where

this program relies heavily on the support of local anglers. Fishermen are

encouraged to hold on to the heads of any legal white seabass so the fish can be

scanned by HSWRI researchers. The recovery of white seabass heads is an integral

part of this program as it provides a method for monitoring the success of the

restocking effort. For more information about the head recovery program please call

(760) 434 9501 or view the HSWRI website athttp://www.hswri.org. In recent years,

tagged, legal-size white seabass have started to be recovered in greater numbers.

This summer a spear fisherman caught a 22 pound white seabass off of La Jolla.

This fish was seven years old, and was released from the Newport Harbor growout

facility in late 1994. Legal-size white seabass have also been recovered from SantaBarbara, Catalina Island, and Mission Bay this year. As the number of fish released
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from the hatchery continues to increase, so too will the number of adults that are

recovered. During this calendar year, nearly 60 thousand juvenile white seabass

have been released into southern California waters. As the year draws to a close,

this number is sure to swell. The total number of white seabass released by this

program during its existence is over 600,000 fish.


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Australian Seabass.

Kingdom Animalia

Phylum Chordata

Class Actinopterygii

Order Perciformes

Family Percichthyidae

Genus Macquaria

Species M. novemaculeata

Australian bass (Macquaria novemaculeata) are a small to medium sized, primarily

freshwater (but estuarine spawning) nativefishfound in coastal rivers and streams

along the east coast ofAustralia. They are a member of thePercichthyidaefamily

and, currently, theMacquariagenus. Australian bass are an iconic, highly predatory

native fish. They are an important member of the native fish faunas found in east

coast river systems and an extremely popular angling species.

Description and Size

Australian bass have a moderately deep, elongated body that is laterally

compressed. They have a forkedcaudal("tail") fin and angularanaland softdorsal

fins. Their spinydorsal finis of medium height, strong and sharp. They have a

medium sized mouth and relatively large eyes than can appear dark in low light or

red in bright light. Theoperculaor gill covers on Australian bass carry extremely

sharp flat spines that can cut fishermens' fingers deeply.
http://en.wikipedia.org/wiki/Fishhttp://en.wikipedia.org/wiki/Fishhttp://en.wikipedia.org/wiki/Fishhttp://en.wikipedia.org/wiki/Australiahttp://en.wikipedia.org/wiki/Australiahttp://en.wikipedia.org/wiki/Australiahttp://en.wikipedia.org/wiki/Percichthyidaehttp://en.wikipedia.org/wiki/Percichthyidaehttp://en.wikipedia.org/wiki/Percichthyidaehttp://en.wikipedia.org/wiki/Macquariahttp://en.wikipedia.org/wiki/Macquariahttp://en.wikipedia.org/wiki/Macquariahttp://en.wikipedia.org/wiki/Caudal_finhttp://en.wikipedia.org/wiki/Caudal_finhttp://en.wikipedia.org/wiki/Caudal_finhttp://en.wikipedia.org/wiki/Anal_finhttp://en.wikipedia.org/wiki/Anal_finhttp://en.wikipedia.org/wiki/Anal_finhttp://en.wikipedia.org/wiki/Dorsal_finhttp://en.wikipedia.org/wiki/Dorsal_finhttp://en.wikipedia.org/wiki/Dorsal_finhttp://en.wikipedia.org/wiki/Dorsal_finhttp://en.wikipedia.org/wiki/Dorsal_finhttp://en.wikipedia.org/wiki/Dorsal_finhttp://en.wikipedia.org/wiki/Dorsal_finhttp://en.wikipedia.org/wiki/Operculum_%28fish%29http://en.wikipedia.org/wiki/Operculum_%28fish%29http://en.wikipedia.org/wiki/Operculum_%28fish%29http://en.wikipedia.org/wiki/Operculum_%28fish%29http://en.wikipedia.org/wiki/Dorsal_finhttp://en.wikipedia.org/wiki/Dorsal_finhttp://en.wikipedia.org/wiki/Dorsal_finhttp://en.wikipedia.org/wiki/Anal_finhttp://en.wikipedia.org/wiki/Caudal_finhttp://en.wikipedia.org/wiki/Macquariahttp://en.wikipedia.org/wiki/Percichthyidaehttp://en.wikipedia.org/wiki/Australiahttp://en.wikipedia.org/wiki/Fish


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Australian bass vary in colour from gold in clear sandy streams to the more usual

bronze or bronze-green colouration in streams with darker substrates and/or some

tannin staining to the water.

Australian bass are, overall, a smallish-sized species, averaging in most watersaround 0.5 kg and 2030 cm. A fish of 1 kg or larger is a good specimen. Maximum

size appears to be around 2.5 kg and 55 cm in southern waters, and around 3.0 kg

and 6065 cm in northern waters.

Typically, Australian bass stocked in man-made impoundments (where they cannot

breed) show greater average and maximum sizes than wild river fish.

Range

Australian bass are found in coastal rivers and streams from Wilsons

Promontory in Victoria east and north along the eastern seaboard to the rivers and

creeks of the Bundaberg region in central Queensland.

Australian bass are not found in the Murray-Darling system because although the

system is extensive, it has only one variable entrance to the Southern Ocean, a

feature that appears to be incompatible with the estuarine breeding habits of

Australian bass and other aspects of their life cycle.

Habitat

In the freshwater reaches of coastal rivers in the warmer months, Australian bass

require reasonable quality, unsilted habitats with adequate native riparian vegetation

and in-stream cover/habitat. Australian bass generally sit in cover during the day.

However, they are fairly flexible about the type of cover used. Sunken timber

(snags), undercut banks, boulders, shade under trees and bushes overhanging the

water and thick weedbeds are all used as cover. Such cover does not need to be in

deep water to be used; Australian bass are happy to use cover in water as shallow

as 1 metre in depth.
http://en.wikipedia.org/wiki/Victoria_%28Australia%29http://en.wikipedia.org/wiki/Bundaberghttp://en.wikipedia.org/wiki/Queenslandhttp://en.wikipedia.org/wiki/Murray-Darling_Basinhttp://en.wikipedia.org/wiki/Snagshttp://en.wikipedia.org/wiki/Snagshttp://en.wikipedia.org/wiki/Snagshttp://en.wikipedia.org/wiki/Snagshttp://en.wikipedia.org/wiki/Murray-Darling_Basinhttp://en.wikipedia.org/wiki/Queenslandhttp://en.wikipedia.org/wiki/Bundaberghttp://en.wikipedia.org/wiki/Victoria_%28Australia%29


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Australian bass are strong swimmers at all sizes and can easily traverse rapids and

fast-flowing water. However, they generally avoid sitting directly in currents to

conserve energy.

At night Australian bass display pelagic (near-surface) behaviour and actively huntprey in shallow water and at the water's surface.

When aggregated for spawning in the broad reaches of estuaries in winter,

Australian bass are less cover oriented, and generally sit in deeper water.

Diet

Harris (1985) found that the common items in the diet of Australian bass are:

terrestrial insects, particularly cicadas

aquatic macroinvertebrates, particularly Trichoptera larvae

crustaceans in the forms of freshwater shrimps and estuarine prawns

small fish, particularly flathead gudgeon (Philhypnodon grandiceps), which are

common in their freshwater habitats.

However, Australian bass are fierce predators and any small creature that swims

across a bass pool such as (introduced) mice and native lizards or frogs are at risk of

being taken by a large Australian bass, and are regularly taken.

Growth and Age

For reasons that are not clear, Australian bass are extremely slow growing.

Australian bass continue the trend present in the larger native fish species of SE

Australia of being very long-lived. Longevity is a survival strategy to ensure that most

adults participate in at least one exceptional spawning and recruitment event, which

are often linked to unusually wet 'La Nia' years and may only occur every one or

two decades. Maximum age recorded so far is 22 years.

As with otherMacquariaspecies, there is sexual dimorphism in Australian bass.

Males tend to have an absolute maximum size of 1.0 kg or less, while females

regularly exceed 1.0 kg and sometimes reach the maximum size of 2.53.0 kg.
http://en.wikipedia.org/wiki/Insecthttp://en.wikipedia.org/wiki/Cicadahttp://en.wikipedia.org/wiki/Macroinvertebratehttp://en.wikipedia.org/wiki/Trichopterahttp://en.wikipedia.org/wiki/Shrimphttp://en.wikipedia.org/wiki/Prawnhttp://en.wikipedia.org/wiki/Mousehttp://en.wikipedia.org/wiki/Lizardhttp://en.wikipedia.org/wiki/Froghttp://en.wikipedia.org/wiki/El_Ni%C3%B1ohttp://en.wikipedia.org/wiki/Macquariahttp://en.wikipedia.org/wiki/Macquariahttp://en.wikipedia.org/wiki/Macquariahttp://en.wikipedia.org/wiki/Sexual_dimorphismhttp://en.wikipedia.org/wiki/Sexual_dimorphismhttp://en.wikipedia.org/wiki/Macquariahttp://en.wikipedia.org/wiki/El_Ni%C3%B1ohttp://en.wikipedia.org/wiki/Froghttp://en.wikipedia.org/wiki/Lizardhttp://en.wikipedia.org/wiki/Mousehttp://en.wikipedia.org/wiki/Prawnhttp://en.wikipedia.org/wiki/Shrimphttp://en.wikipedia.org/wiki/Trichopterahttp://en.wikipedia.org/wiki/Macroinvertebratehttp://en.wikipedia.org/wiki/Cicadahttp://en.wikipedia.org/wiki/Insect


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Males reach sexual maturity at around 34 years of age, females at 56 years of

age.

Aquaculture System Used

Usually, RAS (Recirculation Aquaculture System) is used to culture or breed the

species. RAS is encompasses system used for rearing of aquatic organism where

90% or more system water is recycled. This system is the latest most functional fish

farming system developed to cater need of the fast-growing aquaculture industry.

RAS is used as it gives many advantages as Australian Bass need more protection

from infection and desease.

Australian Bass are perfect to farm dams, you just purchase small fingerlings from a

commercial Bass hatchery and drop them in your dams. They will take several years

to get large enough to eat and 30% generally will not make it to an adult size. You

need to artificially breed bass, though they will roe up in your dam they are not going

to breed in farm dams.

Another system used is floating cage system where the construction cost is more

affordable to be done.

Reproduction

Australian bass spawn in estuaries in winter, generally in the months of July or

August.

The salinity range in which Australian bass spawn is still not clear. Estuaries are

dynamic habitats with daily fluxes in salinity due to tides, and are also affected by

droughts, floods and freshes (minor, temporary rises in flow), making measurements

of preferred spawning salinities for wild Australian bass difficult.

Harris (1986) concluded Australian bass spawned in salinities of 812 parts per

thousand (salt water is approximately 36 ppt), based on capture of recently spawned

larval and juvenile Australian bass in estuaries. Harris (1986) also found Australian

bass sperm had no viability at or below 6 ppt, but was most viable at 12 ppt, the

latter probably being the most relevant fact. However, Harris (in McDowall (ed.),
http://en.wikipedia.org/wiki/Estuaryhttp://en.wikipedia.org/wiki/Estuary


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1996) stated Australian bass spawned in salinities of 1218 ppt, with this statement

based on fishermens' reports of observing wild Australian bass spawnings and some

unpublished data gathered by the NSW Fisheries Department.

Artificial breeding of Australian bass is carried out at much higher salinities thannatural.

Australian bass are highly fecund, with Harris (1986) reporting a mean fecundity

("fertility") of 440,000 eggs from the mature wild female specimens examined, and

one very large specimen yielding 1,400,000 eggs. The eggs are reported as being

demersal ("sinking") in natural spawning salinities, in which case estuarine

vegetation such as sea grass almost certainly play an important role in "trapping"

and protecting eggs. Larvae hatch in 23 days. Juvenile Australian bass migrate into

the freshwater reaches after spending several months in estuarine waters.

Despite spawning in estuaries, Australian bass rely on floods coming down river

systems into the estuaries throughout the winter period, both to stimulate migration

and spawning in adult Australian bass and for strong survival and recruitment of

Australian bass larvae.

Conservation

Wild Australian bass stocks have declined seriously since European settlement.

Dams and weirs blocking migration of Australian bass both to estuaries and to the

upper freshwater reaches of coastal rivers is the most potent cause of decline. Most

coastal rivers now have dams and weirs on them. If Australian bass are prevented

from migrating to estuaries for breeding by an impassable dam or weir, then they will

die out above that dam or weir. Some dams or weirs exclude Australian bass from

the vast majority of their habitat. It is estimated for example that Tallowa Dam on

the Shoalhaven River, once an Australian bass stronghold, currently excludes wild

Australian bass from more than 80% of their former habitat (in early 2010 however a

"fish lift" was fitted to the dam). Dams and weirs also diminish or completely remove

flood events required for effective breeding of adult bass and effective recruitment of

juvenile Australian bass. A related issue is the myriad of other structures on coastal
http://en.wikipedia.org/wiki/Tallowa_Damhttp://en.wikipedia.org/wiki/Shoalhaven_Riverhttp://en.wikipedia.org/wiki/Shoalhaven_Riverhttp://en.wikipedia.org/wiki/Tallowa_Dam


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rivers such as poorly designed road crossings that (often needlessly) block migration

of Australian bass.

Another potent cause of decline is habitat degradation. Unfortunately poor land

management practices have been the norm historically in Australia. Completeclearing of riparian (river bank) vegetation, stock trampling river banks, and massive

siltation from these poor practices as well as poor practices in the catchment, can

severely degrade and silt coastal rivers to the point of being uninhabitable for

Australian bass. TheBega River in southern New South Wales is a particularly

salutory example of a coastal river so stripped of riparian vegetation and so silted

with coarse granitic sands from poor land management practices, that the majority of

it is now completely uninhabitable by Australian bass and other native fish.

As a slow-growing fish, Australian bass are vulnerable to overfishing, and overfishing

has been a driver of decline in Australian bass stocks in past decades. However, the

situation has improved markedly now the majority of fishermen are practicing catch

and release with Australian bass.

Hatchery breeding and stocking of Australian bass is used to create fisheries above

dams and weirs but these are causing concern over genetic diversity issues, use of

bass broodfish from different genetic strains, and introduction/translocation of

unwanted pest fish species in stockings. Stockings can also mask and divert

attention away from serious habitat degradation and decline of wild stocks in

catchments.

Interesting Fact

Fishing for Australian bass is a summertime affair, undertaken during the warmer

months in the freshwater reaches of the rivers they inhabitat. Australian bass are

keenly fished for as they are an outstanding sportsfish, extraordinarily fast and

powerful for their size. Their extraordinary speed and power is probably due to their

significant, strenuous annual migrations for spawning and a life-style that is

migratory in general. Australian bass in their natural river habitats are not to be

underestimated; they head straight for the nearest snags (sunken timber) when

hooked and light but powerful tackle and stiff drag settings are needed to stop them.
http://en.wikipedia.org/wiki/Bega_River_%28New_South_Wales%29http://en.wikipedia.org/wiki/New_South_Waleshttp://en.wikipedia.org/wiki/Catch_and_releasehttp://en.wikipedia.org/wiki/Catch_and_releasehttp://en.wikipedia.org/wiki/Snaghttp://en.wikipedia.org/wiki/Snaghttp://en.wikipedia.org/wiki/Catch_and_releasehttp://en.wikipedia.org/wiki/Catch_and_releasehttp://en.wikipedia.org/wiki/New_South_Waleshttp://en.wikipedia.org/wiki/Bega_River_%28New_South_Wales%29


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Another interesting fact about Australian Bass is it has its migration pattern

especially during spawning and reproduction seasons.

Australian bass are primarily a freshwater riverine species, but must breed in

estuarine waters. Consequently, Australian bass reside in the freshwater reaches ofcoastal rivers for the warmer half of the year or slightly more and the estuarine

reaches in winter, and are highly migratory in general.

A general description of the migratory pattern for adult Australian bass would be:

September: re-enter lower freshwater reaches after spawning

OctoberNovember: movement through middle freshwater reaches

December

February: maximum penetration into negotiable upper freshwaterreaches

MarchApril: slow movement back down through freshwater reaches in

anticipation of spawning run

May: strong spawning run to estuarine reaches

JuneJulyAugust: aggregation and spawning in estuarine reaches

Obviously the timing of these migratory movements varies slightly from the south to

the north of their range. The timing of these migratory movements are also

dependent on river flows, particularly freshes and floods that drown out and make

larger rapids and cascades passable.

Australian bass are found at their highest altitude in the freshwater reaches of rivers

during the months of December, January and February. Research indicates there is

sexual segregation in this non-spawning season for resource partitioning purposes

(Harris, 1988). Males inhabit the lower freshwater reaches of rivers while females

travel far into the middle and upper freshwater (upland) reaches, up to an altitudinal

limit of around 600 metres (if there are no natural or man-made obstructions).

Australian Bass were special on the table because it is good eating, as bass can be

cooked in a variety of ways. Gently grilling or pan frying provides excellent results.
http://en.wikipedia.org/wiki/Upland_and_lowland_%28freshwater_ecology%29http://en.wikipedia.org/wiki/Upland_and_lowland_%28freshwater_ecology%29


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Challenges Faced By Aquaculturist to culture Australian Bass.

Australian Bass needs proper procedure in breeding and culturing. Skilled labor

needed to operate the industry especially if the breeding or culturing using RAS.

Documents

BArramundi azmir