Kina (animal)

Kina (Evechinus chloroticus) is a sea urchin endemic to New Zealand. This echinoderm belongs to the family Echinometridae and it can reach a maximum diameter of 16–17 cm.[1]

For other uses, see Kina.

New Zealand sea urchin
Kina feeding on kelp causing a kina barren near the Noises in the Hauraki Gulf
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Echinodermata
Class: Echinoidea
Order: Camarodonta
Family: Echinometridae
Genus: Evechinus
Species:
E. chloroticus
Binomial name
Evechinus chloroticus

Kina have been a traditional component of Māori diet since pre-European times and has been fished commercially since 1986 in small quantities under the quota management system in restricted areas along the coast of New Zealand.[1][2] Attempts to export E. chloroticus to Asian markets have been unsuccessful, so it may not be an economically attractive species for aquaculture development.[3][4]

Evechinus chloroticus is distributed throughout New Zealand and in some northern and southern offshore islands.[1][5] It is the most common sea urchin species in New Zealand.[6]

Description
The shell of Evechinus chloroticus, with some spines remaining attached to the shell

Evechinus chloroticus is oval in shape, covered by a large number of spines, which are used as protection. In between the spines are a number of tube feet, which help kina to propel themselves along the seafloor.[6]

Habitat

This sea urchin is found all around New Zealand in shallow waters and up to 12–14 metres deep,[1] although there are also intertidal populations in the north of both the North and South Islands.[5]

Evechinus chloroticus prefers areas with moderate wave action.[1] In the north of New Zealand it is found mostly on rocky seafloor areas but also in areas of sandy seafloor.[5][7] In the South Island it is also found in abundant densities throughout the fiords.[8]

Individuals smaller than 1 cm of diameter are found attached under both intertidal and subtidal rocks, whereas individuals between 1–4 cm are found in intertidal and subtidal areas under the rocks, or within small depressions in rocks.[1][5] After the sea urchins reach 4 cm they migrate to open areas.[1]

Diet
Evechinus chloroticus feeding on brown kelp

Evechinus chloroticus is mainly herbivorous,[1] feeding on large brown algae, red algae and encrusting substrate.[5] If kina populations become out of control, kelp forest can be entirely eaten away, leaving bare rocks, also known as Kina Barrens.[6]

Larval stages can feed on different species of unicellular algae in a size range between 5 and 50 µm.[9]

Predators

Molluscs such as the cymatiid gastropods Charonia capax and Charonia rubicunda, starfish, and benthic feeding fishes can feed on individuals of E. chloroticus.[5] The most important predators are the eleven-armed sea star, Coscinasterias calamaria, the seven-armed prickly starfish Astrostole scabra, and the spiny lobster Jasus edwardsii.[1][10]

Reproduction

Evechinus chloroticus has an annual breeding cycle.[11] It becomes sexually mature between 3.5 and 7.5 cm in diameter, depending on the population.[11] Gonads are ripe from October and individuals can spawn from November to February.[1]

Swimming larvae complete development in the water column between 4 and 6 weeks.[12] Other studies related to larval development report development in the laboratory can take between 22 and 30 days.[13][14] The larvae of E. chloroticus are known to settle on substrates covered with coralline algal species, such as Corallina officinalis[13] as well as artificial surfaces.[1] High sedimentation loads in the water column, such as those associated with residential construction, have a negative effect on settling sea urchins.

Evechinus chloroticus can grow between 0.8 and 1 cm in diameter only in its first year of life,[15] and growth rate of in wild populations has been reported between 1–2 cm in diameter annually.[16]

In a human context
Kina shells have become a symbol of the beach in New Zealand

Kina are a traditional food for Māori, often eaten raw from the sea. Kina were known to develop a bitter taste during much of the year, with the blooming of the kōwhai in spring or pōhutukawa in summer indicating times when the roe was particularly palatable.[6]

Kina shells, also known as tests, have become a symbol of coastal New Zealand. The shells have been used in crafts, such as ornaments and jewellery boxes.[6]

Aquaculture

Sea urchin gonads are highly prized in some Asian and European seafood markets where demand has been increasing.[4] In the New Zealand market, the roe can reach NZ$70 per kg.[17] However, because E. chloroticus is not well known in Japan and has a reputation for having a bitter taste, this sea urchin is unable to reach a high price in export markets.[4]

Despite the fact that E. chloroticus is not a profitable species for aquaculture, there are many studies on the complete culture of this species, especially relating to roe enhancement from fished sea urchins. There is strong interest in the production of good quality roe through roe enhancement, which could allow the export of them to markets such as Japan.[18]

Roe enhancement for only nine weeks can give the greatest return for the lowest costs (feeding and maintenance).[18] Also, it is more profitable to enhance sea urchins with low gonad index which are found in the North Island rather than the South Island.[2]

The growth rate in juveniles of E. choloticus maintained in the laboratory is around 1 mm of diameter per month.[13] Maturity in this species depends on the feed quality and availability rather than the sea urchin size. Therefore, it can reach maturity as small as 30 mm if it is fed with a prepared diet.[19]

Artificial diets for sea urchins are well developed. However, more studies in appropriate artificial food for newly settled sea urchins are necessary as well as the design of systems for the nursery culture of post-settled sea urchins.[4]

Toxicology

Copper has a detrimental effect on all stages of E. choloticus. For gametes, LOEC of >15 μg/L over one hour. For the pluteus stage, LOEC of 10.4 μg/L over 4 days. For adults, LOEC of 50 μg/L over 2 weeks.[20]

References
  1. F Barker, Michael (2007). "Chapter 16 Ecology of Evechinus chloroticus". Developments in Aquaculture and Fisheries Science. Vol. 37. Elsevier. pp. 319–338. doi:10.1016/S0167-9309(07)80080-9. ISBN 9780444529404. ISSN 0167-9309.
  2. James, Philip J.; Heath, Philip; Unwin, Martin J. (September 2007). "The effects of season, temperature and initial gonad condition on roe enhancement of the sea urchin Evechinus chloroticus". Aquaculture. 270 (1–4): 115–131. doi:10.1016/j.aquaculture.2007.03.011. ISSN 0044-8486.
  3. James, Phil. "Enhancing urchin roe value". Archived from the original on 2 April 2012. Retrieved 2 June 2023.
  4. James P. 2010. Sea urchins: opportunities and lessons. New Zealand Aquaculture 36 (July/August): 12–13.
  5. Dix, Trevor G. (June 1970). "Biology ofevechinus chloroticus(echinoidea: Echinometridae) from different localities". New Zealand Journal of Marine and Freshwater Research. 4 (2): 91–116. doi:10.1080/00288330.1970.9515331. eISSN 1175-8805. ISSN 0028-8330.
  6. Vennell, Robert (5 October 2022). Secrets of the Sea: The Story of New Zealand's Native Sea Creatures. HarperCollins Publishers Ltd. pp. 112–117. ISBN 978-1-77554-179-0. Wikidata Q114871191.
  7. Choat, J.H.; Schiel, David R (April 1982). "Patterns of distribution and abundance of large brown algae and invertebrate herbivores in subtidal regions of northern New Zealand". Journal of Experimental Marine Biology and Ecology. 60 (2–3): 129–162. doi:10.1016/0022-0981(82)90155-1. ISSN 0022-0981.
  8. Villouta, E.; Chadderton, W. L.; Pugsley, C. W.; Hay, C. H. (December 2001). "Effects of sea urchin(Evechinus chloroticus)grazing in Dusky Sound, Fiordland, New Zealand". New Zealand Journal of Marine and Freshwater Research. 35 (5): 1007–1024. doi:10.1080/00288330.2001.9517060. eISSN 1175-8805. ISSN 0028-8330. S2CID 84395381.
  9. R McEdward, Larry; G Miner, Benjamin (2007). "Chapter 5 Echinoid larval ecology". Developments in Aquaculture and Fisheries Science. Vol. 37. Elsevier. pp. 71–93. doi:10.1016/S0167-9309(07)80069-X. ISBN 9780444529404. ISSN 0167-9309.
  10. Andrew, NL; MacDiarmid, AB (1991). "Interrelations between sea urchins and spiny lobsters in northeastern New Zealand". Marine Ecology Progress Series. 70: 211–222. Bibcode:1991MEPS...70..211A. doi:10.3354/meps070211. eISSN 1616-1599. ISSN 0171-8630.
  11. Dix, Trevor G. (December 1970). "Biology ofEvechinus chloroticus(echinoidea: Echinometridae) from different localities". New Zealand Journal of Marine and Freshwater Research. 4 (4): 385–405. doi:10.1080/00288330.1970.9515355. eISSN 1175-8805. ISSN 0028-8330.
  12. Lamare, MD (1998). "Origin and transport of larvae of the sea urchin Evechinus chloroticus (Echinodermata:Echinoidea) in a New Zealand fiord". Marine Ecology Progress Series. 174: 107–121. Bibcode:1998MEPS..174..107L. doi:10.3354/meps174107. eISSN 1616-1599. ISSN 0171-8630.
  13. Walker, M. M. (December 1984). "Larval life span, larval settlement, and early growth ofEvechinus chloroticus(Valenciennes)". New Zealand Journal of Marine and Freshwater Research. 18 (4): 393–397. doi:10.1080/00288330.1984.9516060. eISSN 1175-8805. ISSN 0028-8330.
  14. Dix, Trevor G. (March 1969). "Larval life span of the echinoidevechinus chloroticus(val.)". New Zealand Journal of Marine and Freshwater Research. 3 (1): 13–16. doi:10.1080/00288330.1969.9515273. eISSN 1175-8805. ISSN 0028-8330.
  15. Lamare, Miles D.; Mladenov, Philip V. (January 2000). "Modelling somatic growth in the sea urchin Evechinus chloroticus (Echinoidea: Echinometridae)". Journal of Experimental Marine Biology and Ecology. 243 (1): 17–43. doi:10.1016/S0022-0981(99)00107-0. ISSN 0022-0981.
  16. Dix, Trevor G. (June 1972). "Biology ofevechinus chloroticus(Echinoidia: Echinometridae) from different localities". New Zealand Journal of Marine and Freshwater Research. 6 (1–2): 48–68. doi:10.1080/00288330.1977.9515409. eISSN 1175-8805. ISSN 0028-8330.
  17. "Award-winning kina research - Wetland construction at Lake Okaro - Ecological engineers - French Polynesia at Bream Bay". NIWA. 1 September 2005. Retrieved 3 December 2021.
  18. James, Philip J.; Heath, Philip L. (June 2008). "Long term roe enhancement of Evechinus chloroticus". Aquaculture. 278 (1–4): 89–96. doi:10.1016/j.aquaculture.2008.03.006. ISSN 0044-8486.
  19. Barker MF, Keogh JA, Lawrence JM and Lawrence AL. 1998. Feeding rate, absorption efficiencies, growth, and enhancement of gonad production in the New Zealand sea urchin Evechinus chloroticus Valenciennes (Echinoidea: Echinometridae) fed prepared and natural diets. Journal of Shellfish Research 17: 1583–1590.
  20. Rouchon, Agnes; Phillips, Nicole (2015-07-08). Effects of copper toxicity on the sea urchin Evechinus chloroticus across multiple life stages and using realistic exposure scenarios. New Zealand Marine Science Society.
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  • 'Sea Urchins', from An Encyclopaedia of New Zealand, edited by A. H. McLintock, originally published in 1966.
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