Collecting finfish broodstock

Broodstock, or brood fish, are the parent fish from which fry and fingerlings are produced. The success of stocking programs, fish farms and aquaculture industries depend upon a reliable supply of healthy fry/fingerlings that have a sound genetic base. Fish reared in hatcheries may be used for grow-out on fish farms, farm dam stocking, stock enhancement, conservation stocking or the aquarium trade.

Hatchery operators require access to new broodstock periodically to undertake their breeding programs. Broodstock are usually sourced externally (dams, lakes and rivers) and held in facilities (ponds, cages, tanks) at the hatchery.

Replacement broodstock are required due to declining reproductive performance in captivity, broodstock mortality or to maintain genetic diversity. NSW DPIRD regulates the collection of broodstock, and hatchery operators must obtain a permit and authorisation before collecting commences.

Applying for a broodstock collection permit

Permits are issued under Section 37 of the Fisheries Management Act 1994 to regulate broodstock collection.
Several factors are taken into consideration before NSW DPIRD grant a broodstock collection permit. These include:

The species and number of broodstock required.
The source of broodstock.
The hatchery facilities for broodstock holding, artificial spawning and larval rearing.
The proposed broodstock collection methods.
The potential to obtain broodstock from locations other than the wild, eg. captive stock.
Consideration of any impacts on threatened fish species.
Any potential conflict with the public, commercial or recreational anglers.

To ensure the activity is permissible, it will be assessed by the Aquaculture Unit, and also conservation managers, Fisheries Officers, and Marine Park Managers, where applicable. If there are threatened species, populations or endangered ecological communities present in the collection area, a "7 Part Threatened Species Test" report may be required.

Broodstock collection methods

The physical injury and physiological stress resulting from capture, handling, transporting, and holding broodstock can have a detrimental effect on survival and spawning success. Poor water quality, rough handling, and capture may cause females of some species to undergo rapid physiological changes resulting in breakdown (resorption) of the eggs in the ovary.
The broodstock collection permit will outline the collection method to be used. These include:

Haul or seine net
Gill net
Trap
Angling
Any legal recreational fishing method

Angling or capture of the following 3 species is prohibited:

Trout Cod (Maccullochella macquariensis)
Eastern Freshwater Cod (Maccullochella ikei)
Macquarie Perch (Macquaria australasica)

Species

Australian Bass

Genetic variations occur between populations ranging from Queensland to Victoria.
Fingerlings spawned from the collected brood fish must only be stocked into waters as specified by NSW DPIRD.

Golden Perch (Macquaria ambigua)

Genetic variations occur between populations ranging from Queensland to Victoria.
Fingerlings spawned from the collected brood fish must only be stocked into waters as specified by NSW DPIRD.

Murray Cod (Maccullochella peelii peelii)

Brood fish should not be handled a minimum of 6 months prior to the hatchery breeding season.
Brood fish have relatively low fecundity (approx. 5,000 eggs/kg).
Natural pond spawnings usually result in higher hatch rates than hormone-induced spawnings.
The viability of eggs and larvae from brood fish held in ponds decreases after 6-7 years.
Progeny should only be stocked back into waters from which the brood fish were captured.

A review of the genetic work undertaken since 2004, indicates that there is strong evidence to support no requirement for genetic separation of Murray Cod in NSW.

The HQAS now has no specific genetic zones for Murray Cod in NSW.

Silver Perch (Bidyanus bidyanus)Silver Perch (Bidyanus bidyanus)

Significant decline of wild populations in most parts of the Murray-Darling River System.
Low level of genetic variation in wild stocks.
Threatened species, officially classified as "vulnerable".
The fecundity of brood fish is high (100,000 – 150,000 eggs/kg), but decreases within 4 – 5 years in captivity.
NSW DPIRD maintains discrete, wild genetic lines in captivity.
The collection of fish from impoundments and farm dams is not recommended.
Collection of wild brood fish from rivers is prohibited.

Handling Brood Fish

Handling of brood fish should be kept to an absolute minimum.
Brood fish should always be kept in water.
Use an anaesthetic to reduce physical injury and stress.
Good water quality should always be maintained especially dissolved oxygen.
When transferring brood fish, support with hands, fine knotless netting or a sling.
Transport brood fish in well oxygenated, sealed tanks with plenty of room for movement.
To minimise osmotic stress and infection, transport and quarantine brood fish in a salt solution.

NSW Hatchery Quality Assurance Scheme

Techniques for the large-scale hatchery production of the Australian native fishes Murray Cod (Maccullochella peelii peelii), Golden Perch (Macquaria ambigua) and Silver Perch (Bidyanus bidyanus) were developed at the Narrandera Fisheries Centre in the early 1980’s, and commercial hatcheries began to produce and sell fingerlings in 1982/83.

Over the last 25 years, the regular stocking of native fish into impoundments and rivers has established large, popular recreational fisheries and contributed significantly to the conservation of these species.

In recent years, there have been concerns about some aspects of native fish hatcheries, in particular genetics, diseases and trash fish. Research has found discrete populations of Murray Cod, Golden Perch and Silver Perch in other drainages and within the Murray-Darling River System; mixing of populations through inappropriate stockings may reduce their reproductive fitness. Pathogens and diseases that are transferred on hatchery fish may reduce survival and introduce new diseases to regions and farms.

To address these concerns, NSW Department of Primary Industries and Regional Development has developed The NSW Hatchery Quality Assurance Scheme (HQAS) which accredits fish hatcheries for the production of Murray Cod, Golden Perch, Silver Perch and Australian Bass fingerlings for enhancement stocking programs for recreational fishing. The scheme was developed by NSW DPIRD Aquaculture and Recreational Fishing Staff with significant industry consultation and input.

A major objective of stocking programs is to maintain genetic integrity and genetic diversity in wild populations, ensuring “fitness” and evolutionary potential. The HQAS is designed to meet these genetic goals, and to ensure good health of stocked fish and the absence of non-target species.

For more information and detail about the HQAS please see the HQAS Manual.

The HQAS divides the state into various regions by drainage; these regions are based on current knowledge of the population genetics of each species. The regions set out the areas from which brood fish must be collected; in order for a hatchery to stock a particular region, brood fish must be collected from that region. The key genetic regions for Murray Cod, Golden Perch and Australian Bass in NSW are shown on the following maps.

Murray Cod

The latest research indicates that there are no specific genetic zones in NSW.

Golden Perch

The latest research indicates that there are no specific genetic zones in NSW.

Australian Bass

NSW map showing the regions for Australia Bass

North Coast (AB1): All rivers north of the Macleay River
Central Coast (AB2): All rivers between the Macleay and the Hawkesbury River (both rivers included)
South Coast (AB3): All rivers south of the Hawkesbury River