Girella cyanea

Girella cyanea, also known as the blue drummer or Australian bluefish, is a species of sea chub native to inshore waters, around 6 metres (20 ft) depth, from Australia to New Zealand and the Kermadec Islands. Sightings were first recorded in 1881 but the species made its debut in scientific publications in 1919 in Theodore Roughly's Fishes of Australia and Their Technology.[1]

Girella cyanea
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Kyphosidae
Genus: Girella
Species:
G. cyanea
Binomial name
Girella cyanea

Description

Girella cyanea can be recognized by its blue coloration and yellow spots, with its blueish color becoming a greyish-green in post mortem.[2] The adults of this species are they can attain a length of 76cm and their bright flank spots are distinctive. When they are younger they are greeny-grey in colour and the spots are paler yellow. These fish have a small beak-like mouth and they have large scales.[3]

Sea chubs are easily recognized by distinct morphological characteristics such as their ovate-shaped bodies, small mouths, and weakly-forked strong caudal fin.[4] A key characteristic also being a spinous dorsal fin with low spines followed by a higher evenly curved or falcate soft dorsal fin.[4]

Distribution & habitat

Girella cyanea are commonly found in the south-west Pacific Ocean; occurring along the east coast of Australia from Flinders Reef off Cape Moreton in Queensland to Eden in southern New South Wales. The species can also be found at Elizabeth and Middleton Reefs, Lord Howe and Norfolk Islands, and New Zealand's North and Kermadec Islands.[5] Bluefish are ocean dwellers and do not generally enter rivers or estuaries.[5]

Juveniles are known to live in tidal pools until they reach adulthood and form schools over reef areas. Adults can typically be found in coastal and offshore rocky reef areas in New South Wales at depths ranging from 5–30 metres (16–98 ft).[5]

Ecology

Girella cyanea are omnivorous; they are known to eat crustaceans, smaller fishes, mollusks; along with calcareous seaweeds, brittle stars, cunjevoi, and marine worms. They are known to feed at dawn and dusk when they are most active.[6]

An ontogenetic diet was found in fish less than 40 millimetres (1.6 in) standard length. Those found in intertidal habitat having a mainly carnivorous diet and a digestive system without developed pyloric caeca.[7] In contrast, pyloric caeca were well-developed in fish larger than 40 millimetres (1.6 in) and their diets possessed increased ingestion of algae.[7]

Reproduction

Girella cyanea is a fast-growing and long-lived fish, with the oldest observed specimen being 41 years old.[7] It is believed they transition into sexual maturity between 2 and 5 years of age or when they reach 200 millimetres (7.9 in) in length.[7]

Conservation efforts

A fishing closure was placed across the state of New South Wales in 2006 due to the lack of sightings at the coast; despite the lack of official endangered species status.[8] However, recreational fishing is still permitted on Lord Howe Island. A bag limit of 5 fish per person per day is enforced in protection zones across the Marine Park.[7]

Taking or possessing bluefish from New South Wales waters, other than designated areas, is an offense that carries a multitude of penalties. Penalties for taking bluefish in contravention of the fishing closure can include fines of up to $110,000 for corporations while individuals can face fines of up to $22,000 along with up to 6 months in prison, or both.[8] Penalties for possessing a Blue Drummer despite the fishing closure can include fines of up to $55,000 for corporations, while individuals can face fines of up to $11,000 and up to 3 months in prison, or both.[8]

References
  • "Girella cyanea". Integrated Taxonomic Information System. Retrieved 18 April 2006.
  • Tony Ayling & Geoffrey Cox, Collins Guide to the Sea Fishes of New Zealand, (William Collins Publishers Ltd, Auckland, New Zealand 1982) ISBN 0-00-216987-8
  1. Roughley, Theodore C. Fishes of Australia and Their Technology (Technical Education Series No. 21 ed.). Department of Education, New South Wales. p. 296. ISBN 978-1125465165.
  2. Hutchins, Barry; Swainston, Roger (1999). Sea Fishes of Southern Australia: Complete Field Guide for Anglers and Divers (2 ed.). Gary Allen Pty Limited. p. 180. ISBN 1875169784.
  3. Irene Middleton (September 2019). "Bluefish (Girella Cyanea) Profile". New Zealand Fishing News. Retrieved 22 April 2020.
  4. Freihofer, Warren C.; Parenti, Lynne R.; Lin, Maung W. "Perciform". Encyclopædia Britannica. Encyclopædia Britannica, inc. Retrieved 26 March 2020.
  5. "Bluefish". NSW Department of Planning, Industry and Environment. New South Wales Government. Retrieved 30 March 2020.
  6. Yagishita, Naoki; Nakabo, Tetsuji (1 November 2003). "Evolutionary trend in feeding habits of Girella (Perciformes: Girellidae)". Ichthyological Research. 50 (4): 358–366. doi:10.1007/s10228-003-0180-8. S2CID 11291253.
  7. Lewis, MA. The Life History and Ecology of Bluefish, Girella cyanea, at Lord Howe Island. University of Technology Sydney. hdl:10453/33294.
  8. Bean, Meghan G.; Covarrubias, Rebecca; Stone, Jeff (February 2002). Health Agency Measure (PDF). CONSERVATION OVERVIEW and ACTION PLAN for AUSTRALIAN THREATENED and POTENTIALLY THREATENED MARINE and ESTUARINE FISHES. ISBN 0-642-54786-6.
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