Scientific name: Rexea solandri
Other names: Barraconda, common gemfish, deepsea kingfish, hake, king barracouta, king couta, silver gemfish, silver kingfish
Description: Gemfish have moderately elongate compressed bodies. The body is iridescent bluish above and silver below. The mouth is relatively large and reaches to under the front of the eyes. Gemfish have large fang-like teeth at the front of the jaws, followed by a row of smaller compressed teeth. Gemfish have two dorsal fins followed by two separate finlets.
Size (length and weight): Up to about 1.2 metres in length and 15 kg. Commonly found at 60‑90 cm in length and 2‑6 kg. Females grow larger than males.
Life span: Up to 17 years. Females live longer than males.
Habitat: Gemfish is a bottom-dwelling species that inhabits temperate waters of Australia and New Zealand. They are generally found in large schools at depths of 100‑800 metres on the continental shelf and upper slope. Juveniles are pelagic.
Prey: Benthopelagic fish such as grenadier, as well as squid and crustaceans.
Predators: Larger fish and sharks, and marine mammals such as seals.
Reproduction: Females reach reproductive maturity at 4-6 years, with males reaching maturity at 3-5 years. Spawning occurs in northern and or central New South Wales during winter for Australia’s eastern stock, and to the west of the Great Australian Bight during summer for the western stock. Mature gemfish aggregate prior to spawning in the eastern stock. Spawning dynamics and spawning migrations are not well known for the western gemfish stock. Females produce 1-1.5 million eggs each spawning season depending on their body size. Development of eggs and larvae is not well described.
Other notes: Eastern stocks are listed as Conservation Dependent under the EPBC Act and are managed under AFMA’s Eastern Gemfish Stock Rebuilding Strategy.
|Fishery found in||Gear used||Catch of this species is targeted or incidental|
|Southern and Eastern Scalefish and Shark Fishery – Commonwealth Trawl Sector||Bottom trawl||Targeted in the western zoneIncidental catch in the eastern zone|
|Southern and Eastern Scalefish and Shark Fishery – Great Australian Bight Sector||Bottom trawl||Targeted in the western zone|
|Southern and Eastern Scalefish and Shark Fishery – Gillnet Hook and Trap Sector||Handline, dropline and setline (bottom)||Incidental|
|Recreational||Rod and line and electric (automatic) reel||Targeted, but may be incidentally caught while targeting blue-eye trevalla|
Management of catch
The Commonwealth catch of gemfish around Australia is managed by quota. This means the catch of this fish by commercial fishers is restricted by weight.
AFMA also restricts the type and amount of gear that can be used to fish for gemfish.
Commercial fishermen are required to fill in records of their catches, during each fishing trip and when they land their catch in a port. This helps us keep records of how much is being caught.
AFMA decide on the amount that can be caught each year from expert advice and recommendations from fisheries managers, industry members, scientist and researchers.
Commercial fishermen are not allowed to target gemfish in the eastern zone.
There are two stocks of gemfish found in Australian waters, an eastern stock and a western stock. These stocks are separated by a boundary at the western end of the Bass Strait.
Gemfish are caught primarily on or near the bottom in deep water.
The eastern stock of gemfish is most commonly caught during the winter months (June to August) when they begin an annual spawning run along the south eastern coast of Australia.
The western stock of gemfish is caught year round.
Fishing gear and environmental impacts
The main fishing method used to catch gemfish is bottom trawling.
Sometimes, bottom trawling can catch unwanted species of fish (not the type of fish the net was supposed to catch). This is known as bycatch and it is monitored by on-board fishery observers who assess the environmental impact of the trawling.
Although it is not physically possible to trawl on reef structures, significant long-term damage can occur if sensitive habitat areas like corals, sponges and seagrass beds are trawled. To ensure these sensitive habitat areas are protected from trawling, management arrangements such as area closures are extensively used.
AFMA carries out ecological risk assessments (ERA) for all of its major fisheries. The impact of bottom trawl on bycatch species and habitats has been assessed as part of the ERA. AFMA mitigates, or reduces, that impact through its ecological risk management (ERM) strategy. The ERM details a number of management arrangements and strategies which aim to reduce the impact of fishing on the environment, including:
- minimum mesh sizes for bottom trawls to reduce the catch of small and juvenile fish
- mitigation devices to reduce interactions with threatened, endangered and protected species
- and closing areas to fishing to protect vulnerable species and habitats.
All bottom trawl boats are required to have a seabird management plan in place to reduce interactions with seabirds during fishing.