Blue moki

Blue moki (Latridopsis ciliaris) is a species of trumpeter native to the southwestern Pacific Ocean around New Zealand and occasionally off southeastern Australia at depths of 10 metres (33 ft) and greater. Juveniles inhabit inshore waters, preferring rocky reefs while adults mostly occur in offshore waters forming schools over open bottoms. Some solitary adults can be found on reefs. This species can reach a length of 80 centimetres (31 in) FL, though most do not exceed 63 centimetres (25 in) TL. This species is commercially important and is also popular as a game fish.[1]

Blue moki
Not evaluated (IUCN 3.1)
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Actinopterygii
Order:
Perciformes
Family:
Latridae
Genus:
Latridopsis
Species:
L. ciliaris
Binomial name
Latridopsis ciliaris
Synonyms
  • Anthias ciliaris J. R. Forster, 1801

Despite the similarities in their common names, the blue moki are not closely related to the red moki (Cheilodactylus spectabilis), a species of morwong.

Blue moki in New Zealand occur throughout mainland waters from the Three Kings Islands to the southern edge of the Snares Shelf, and at the Chatham Islands. A single record of blue moki from the southern end of the Kermadec Island chain was reported, but this requires verification; it is not known if the species occurs elsewhere in the Kermadecs. Blue moki are also found in small numbers at the Auckland Islands.

Identification

Blue moki are very similar to the copper moki in shape and size, but they differ in colour throughout the adult stage of their lives.[2] Blue moki are knowing for their piercing colours, which is an array of pink and olive.[3] A blue moki's phenotype is true to its name - they are dark blue/grey.[2] They have a black edge to the caudal and soft dorsal fin.[3] Blue moki belongs to the family Latridae commonly known as trumpeter,[4] which has 4 subspecies of abundance in New Zealand waters. The copper moki which is another member of the genus is located in New South Wales and Tasmania but is rarely seen in New Zealand waters.[5] The colouration of blue moki changes throughout its life time from juvenile to adolescences, their body colours change from green in juveniles to green/grey and through to blue/grey in large adults.[3]

Geographic distribution

Natural global range

Past research has found that blue moki are an endemic species to New Zealand,[5] but more recent resources suggest that blue moki distribution patterns are more widespread, with sighting of the species occurring off Tasmania and New South Wales.[4]

New Zealand range

Blue moki are widespread throughout New Zealand. They are distributed from the Kermadec Islands to the Auckland Islands[3] down to Stewart Island, and abundant off the east coast; they have also have been recorded in the Chatham Islands. The population of blue moki on the west coast is uncertain, but there have been small commercial hauls taken off shore from New Plymouth and Greymouth.[5]

Habitat

Blue moki are found in the continental shelf north south of the Chatham islands in depths of 10–200 metres.[6] Many adults take part in an annual migration between Kaikoura and East Cape.[7] Juvenile blue moki are then found inshore in coastal rocky reefs; whereas adults tend to school offshore over open bottom areas. There are some adults that tend to remain on coastal reefs in shallower waters.[8] Juvenile blue moki have been observed to prefer rocky-reef type habitats in shallow waters,[9] most of the adult blue moki school offshore on sandy open bottom habitats but some adult blue moki do not join the schools and stay in the rocky-reef type habitats.[10]

Lifecycle and phenology

Blue moki grow at a rapid rate growing between 5–6 centimetres per year, growth potentially slows with fish between the age of 10–20 years reaching 60 centimetres and there have also been fish recorded at 33 years of age with them being over 80 centimetres long.[7] Blue moki can weigh up to 10 kg.[11] The blue moki reach sexual maturity at 40 centimetres which equates to 5–6 years of age.[3] Migration occurs annually. It begins in May/June (Winter) when blue moki begin to travel from Kaikoura on the East Coast on the South Island up to the only known spawning ground for blue moki in New Zealand, which is in the Mahia Peninsula to the East Cape region. Spawning occurs from August to September.[7] They then pass back by Kaikoura in October.[6] The larvae period of the blue moki spawn lasts about six months; from there juveniles are then found inshore in coastal rocky reefs, whereas adults tend to school offshore over open bottom areas. There are some adults that tend to remain on coastal reefs in shallower waters New Zealand.[7] Blue moki morality other than for commercial fishing reasons is low.[11]

Diet and foraging

Blue moki feeds at the bottom, on a wide range of benthic invertebrates.[5] It consumes a mouthful of turfing substrate, it then winnows out the prey.[12] Blue moki intestines are often found with ingested sand and mud. This is a result of them feeding on benthic species such as crabs, gastropod, bivalve molluscs, polychaete worms and Munida gregaria.[5] They also feed on juvenile sea urchins.[12] Juvenile blue moki are located on reefs and eat small crustaceans amongst seaweeds, while adults prey on crabs, other crustaceans, shellfish and worms, which they suck from the sand or mud.[13]

Predators

Blue moki are seen as a ‘game’ fish in New Zealand and are commercially fished, this is why Humans are seen as one of blue moki's predators.[8] Blue moki stocks were seriously depleted in New Zealand in 1975.[8] Humans are the blue moki's largest predator, which fishes them commercially using set nets in the areas between East Cape and Kaikoura. Catches have been consistent at around 400 tonne per year; fish mortality other than commercial fishing is low.[14] Moki are also caught recreationally through spear fishing and boat fishing in small catch.[14]

Parasites
Group Species Location on host[15]
Monogenea Mediavagina latridis Gills
Digenea Genoliena dactylopagri Stomach
Holorichis pulcher Intestines
Proctoeces sp. Posterior intestine
Tubulovesicular angusticauda Stomach
Nematoda Cucullanellus sheardi Stomach
Copepoda Aethon morelandi Stomach
Lepeophtheirus erecsoni Gills
Lepeophtheirus sp. Skin

Cultural use

Maori view blue moki as having special significance in community and life believing that blue moki spawn in Cape runaway and that there are traditional fishing grounds for blue moki where customary fishing practices took place in earlier times. Iwi also consider fishing blue moki by set nets in the area a cultural offence.[16]

Commercial Fisheries

Blue moki is mostly caught on the east coast of New Zealand between Otara and Kaikoura it is a low value fishery. The commercial catch is caught as a bycatch of trawling and set netting for other target species. There are management practices in place for the blue moki fisheries such as a minimum catch size of 40 cm, area restrictions on certain types of fishing methods and a minimum net size of 114mm for target set net fishing of blue moki[17]

Recreational Fisheries

Blue moki are a very popular fish targeted by recreational fishermen, they are caught in a variety of ways such as spearfishing, catching on the rod and reel and set netting like commercial fisheries they are legally required to be above 40 cm in length and a minimum set net mesh size of 114 mm. There is also a bag limit of 15 fish per person.[17]

References
  1. Froese, Rainer and Pauly, Daniel, eds. (2013). "Latridopsis ciliaris" in FishBase. December 2013 version.
  2. "Make mine a moki". Stuff. Retrieved 2019-05-07.
  3. Smith, P. J.; Roberts, C. D.; Benson, P. G. (2001). "Biochemical‐genetic and meristic evidence that blue and copper moki (Teleostei: Latridae: Latridopsis) are discrete species". New Zealand Journal of Marine and Freshwater Research. 35 (2): 387–395. doi:10.1080/00288330.2001.9517009.
  4. Roberts, Clive D. (2003). "A new species of trumpeter (Teleostei; Percomorpha; Latridae) from the central South Pacific Ocean, with a taxonomic review of the striped trumpeter Latris lineata". Journal of the Royal Society of New Zealand. 33 (4): 731–754. doi:10.1080/03014223.2003.9517756.
  5. Francis, Malcolm P. (1981). "Age and growth of moki, Latridopsis ciliaris (Teleostei: Latridae)". New Zealand Journal of Marine and Freshwater Research. 15 (1): 47–49. doi:10.1080/00288330.1981.9515896.
  6. OECD (2010). OECD Economic Surveys: Norway 2010. OECD Publishing. pp. 133–. doi:10.1787/808847412487. ISBN 978-92-64-07713-3.
  7. "New Zealand Ministry for Primary Industries Website". fs.fish.govt.nz. Retrieved 2019-05-07.
  8. "Latridopsis ciliaris summary page". FishBase. Retrieved 2019-05-07.
  9. Francis, Malcolm P. (1981). "Age and growth of moki, Latridopsis ciliaris (Teleostei: Latridae)". New Zealand Journal of Marine and Freshwater Research. 15 (1): 47–49. doi:10.1080/00288330.1981.9515896. ISSN 0028-8330.
  10. "Blue Moki (MOK)". Fishery Summary: 142. 2008.
  11. "Marine fish communities and land use in the Gisborne District, Prepared for Gisborne District Council" (PDF). 2010.
  12. Johnson, Teresa R.; Wilson, James A.; Cleaver, Caitlin; Morehead, Graham; Vadas, Robert (2013). "Modeling fine scale urchin and kelp dynamics: Implications for management of the Maine sea urchin fishery". Fisheries Research. 141: 107–117. doi:10.1016/j.fishres.2012.05.008.
  13. MacDiarmid, A (2015). Assessment of the scale of marine ecological effects of seabed mining in the South Taranaki Bight: Zooplankton, fish, kai moana, sea birds, and marine mammals (PDF). National Institute of Water and Atmospheric Research, New Zealand. Archived from the original (PDF) on 2018-01-29.
  14. Parson, D. (2010). "Marine fish communities and land use in the Gisborne District, Prepared for Gisborne District Council" (PDF).
  15. Hine, Mike; Jones, John Brian and Diggles, B. K. (2000) A checklist of the parasites of New Zealand fishes including previously unpublished records. NIWA Technical Report 75. ISBN 0478084692
  16. "New Zealand Ministry for Primary Industries Website". fs.fish.govt.nz. Retrieved 2019-04-30.
  17. Industries, Ministry for Primary. "Download document | MPI - Ministry for Primary Industries. A New Zealand Government Department". www.mpi.govt.nz. Retrieved 2019-05-07.
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