Jump to content

Ovalipes catharus

This is a good article. Click here for more information.
From Wikipedia, the free encyclopedia

Ovalipes catharus
Dorsal view of a preserved Ovalipes catharus specimen with the anterior facing the bottom of the frame. A note at the top reads "Norman Douglas collection. Beneath that, another reads: "Ovalipes bipustulatus. Swimming crab. Maketu, Bay of Plenty, 5 April, 1977. Ashore, dead, in a wash up of seaweed on the western shore of the peninsula. N. Douglas." A note to the right of these two, another reads: "AK 78855. Auckland Museum, N.Z. Porcellanidae. Ovalipes catharus. L3523: N.Z., Bay of Plenty, Maketu, on the western shore of the peninsula Washed up, dead in seaweed. c. 37 44.8 S, 176 27.8 E. Coll: Douglas, N., 05 APR 1977. CMROVA.CAT." To the crab's left is an OpCard 201 colour correction chart. A ruler in centimetres is at the bottom of the frame, revealing a carapace width of approximately 100 millimetres. The crab's carapace and chelipeds are a light-yellowish colour with maroon spots. The walking legs and paddles are a dark, sandy brown.
Ventral view of Ovalipes catharus in a shallow puddle on top of dark sand. The crab is ostensibly dead and covered in sand particles. The abdomen and all 10 legs are visible; the abdomen and underside of the chelipeds and walking legs are a bright white.
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Order: Decapoda
Suborder: Pleocyemata
Infraorder: Brachyura
Family: Ovalipidae
Genus: Ovalipes
Species:
O. catharus
Binomial name
Ovalipes catharus
(White in White and Doubleday, 1843)
Synonyms[1]
  • Portunus catharus White in White and Doubleday, 1843

Ovalipes catharus, commonly known as the paddle crab,[a] swimming crab,[b] or Māori: pāpaka,[5] is a species of crab in the family Ovalipidae.[1][6] They are found in shallow, sandy-bottomed waters around the coasts of New Zealand, the Chatham Islands, and uncommonly in southern Australia.[7][8][9] They are opportunistic and versatile feeders active mostly at night, preying predominantly on molluscs and crustaceans.[10][11] They are also highly prone to cannibalism both as part of their regular diet and as part of their mating behaviour.[12][13] Their paddle-shaped rear legs and streamlined carapace allow them to swim rapidly to capture prey and to burrow in the sand in order to escape predation.[14] Their mating season is in winter; the male carries the female until she moults, after which the two mate and the female likely moves into deeper waters to incubate and disperse her larvae.[15][16]

Commercial fisheries have harvested paddle crabs since the 1970s, with catches declining considerably from a peak in the late 1990s.[17] Their population is expected to be increasing,[18] although ecologists have raised concerns that the paddle crab could become outcompeted by Charybdis japonica, an invasive species with a similar size, diet, and habitat.[19] O. catharus is present in Māori culture, both as an artistic motif and as a traditional source of food.[20]

Description

[edit]
Frontal view of Ovalipes catharus walking on the seabed or potentially resting on a dark-coloured rock. The chelipeds, mouthparts, eyestalks, antennae, walking legs, and some of the dorsal carapace are visible. Fine, white hairs line the area directly underneath the lateral teeth. Fine hairs in the orbits and above the mouth are a sandy brown colour. The bottoms of the eyes are covered in sand.
The front of O. catharus directly under the carapace is lined with setae.[21]

Ovalipes catharus has an oval-shaped, streamlined, and slightly grainy carapace with five large teeth to either side of the eyes and four teeth at the front.[7][14][21] It is overall sandy grey with orange-red highlights and dotted with small, brown spots.[7][22] Its carapace has two large, maroon eye-spots at the rear, two smaller eye spots near the front, and cervical grooves which form a butterfly-shaped mark near the centre.[7][23][24] Its underside is white, and its rear legs – which are flattened and function as swimming paddles – have a purplish tinge.[7][25] The area above its mouth near the base of the antennae is somewhat hairy, and a line of setae runs from the base of its deep orbits out to the area underneath the carapace teeth.[21] Like other Ovalipes, O. catharus has well-developed, relatively large eyes.[14][26] Unlike about half of known Ovalipes species, however, it exhibits no iridescence as a form of signalling.[27]

Ovalipes catharus' relatively short chelipeds feature spines and granules on the wrists and setae on the posterior border of the arms.[21] The left (minor) chela is smaller than its right (major), and both dactyli are slender and tapered.[28] The minor chela grows in direct proportion to the carapace width in females, but it may exhibit negative allometry in males.[29][c] The minor chela, used for cutting, is lined with small, conical teeth on both fingers, while the major chela also features a large proximinal tooth used for crushing.[31] It has three pairs of walking legs,[d] which are somewhat granular and relatively flat.[7][34] The flattened rear paddles are fringed with setae.[7]

Mature male paddle crabs can reach carapace widths up to a reported 150 mm (5.9 in).[11] Individuals from shallow waters, 0.1–0.5 metres (4–20 in) deep, have a carapace width of only 10–15 millimetres (0.4–0.6 in), while males from 5–15 m (16–49 ft) are 100–140 mm (3.9–5.5 in) wide.[35] The largest males weigh around 600–700 g (21–25 oz).[36] Sexually mature females typically have a carapace width of >70 mm (2.8 in) and are known to be as wide as about 115 mm (4.5 in).[37][38] Abdomen growth in males and juvenile females is isometric with carapace width, but after the pubertal moult, the female's abdomen exhibits positive allometry.[29] Relative length diminishes compared to the width as the crab grows.[29] On average, the carapace is about 1.35x as broad as it is long.[21]

It has a long period of larval development – about two months[39] – with eight zoeal stages.[40] The zoea is transparent or blackish, later develops red chromatophores, and then turns black when it moults into a megalopa.[40] The zoea features a prominent dorsal spine and similarly prominent rostral spine; neither are present in its megalopal form, whose carapace is entirely smooth.[40] Paddle crabs have 13 instars after their megalopal form and reach their maximum size at 3–4 years old.[41]

Internal anatomy

[edit]

Ovalipes catharus is either an osmoconformer or a weak osmoregulator.[42] It can reverse its ventilatory flow by adjusting the sizes of apertures located at the bases of its legs.[43] These apertures lead into the branchial chamber and are covered in dense setae for filtration.[44] Unlike in most decapods, this period of reversed flow can be sustained, and it is commonly seen when the crab is buried or at rest.[45]

Its heart is a single-chambered ventricle which ejects hemolymph to seven arteries.[46] Five arteries, including the anterior aorta, leave the heart anteriorly and supply organs such as the cerebral ganglion, eyes, antennae, hepatopancreas, and various digestive organs.[46] One, which leaves the heart ventrally, is called the sternal artery and accounts for nearly 70% of flow; this branches into vessels which supply its five pairs of legs, the largest of which are those supplying its rear paddles.[47] Finally, a relatively small posterior aorta runs down the middle of the crab's abdomen.[48]

Ovalipes catharus is a stenotherm.[49] An increase in water temperature of just a few degrees substantially accelerates their growth.[50] At summer temperatures of about 20 °C (68 °F), O. catharus' heart rate is approximately 50 bpm.[51] Above this temperature, its heartbeats begin to shorten.[49] Its heart rate is more than doubled to 125 bpm at 25 °C (77 °F),[52] and temperatures around 30 °C (86 °F) are fatal.[49] Phosphorylation of ADP during respiration also decreases at temperatures over 20 °C (68 °F), indicating reduced ability of the mitochondria to produce ATP.[53] At temperatures around 10 °C (50 °F) – near the lower end of what it experiences in the wild[54]O. catharus needs to be actively encouraged to eat, eats less overall, and takes over three times as long to digest its food as it does at 20 °C (68 °F).[55][56]

Ovalipes catharus hears underwater by using a small canal system located under its first antenna called a statocyst.[57] The statocyst contains an agglomerate of sand particles called the statolith and functions similarly to the otolith in vertebrates.[58] They are known to be able to hear sounds between at least 40–2000 Hz, but they are especially sensitive to the range between 100–200 Hz.[59] O. catharus uses a yet-unknown internal mechanism to create a broad-frequency, multi-pulse "rasp" sound which is hypothesised to communicate food availability to other members of the species.[60] Males additionally use a yet-unknown internal mechanism to produce a sub-bass sound used in their mating behaviour.[61]

Taxonomy

[edit]
Rear view of Ovalipes catharus swimming with its rear, paddle-shaped legs raised and its walking legs spread out laterally. Set against a teal, watery background with no visible seabed.
O. catharus use their paddle-shaped rear legs to swim.[25]

Ovalipes catharus is colloquially known as the paddle crab, the common swimming crab,[4] or Māori: pāpaka.[5] They were described in 1843 by zoologist Adam White, originally placed into the genus Portunus.[22] In 1968, marine biologists William Stephenson and May Rees identified, on the basis of its colour patterns, that it actually belonged in Ovalipes.[62] Having been synonymised with O. punctatus alongside three other species prior to 1968, O. catharus is part of a distinct subgroup of Ovalipes which also includes O. australiensis, O. elongatus, O. georgei, O. punctatus, and O. trimaculatus.[63][e] O. catharus additionally closely resembles (and is likely conspecific with) a fossilised cheliped fragment from New Zealand's Upper Pleistocene.[65][66] Three aspects taken together reliably distinguish O. catharus from other members of Ovalipes: fine granules on the raised ridges of the top side of its hands, moderately fine stripes on the underside of its hands, and a notably broad carapace (~1.35x broader than long).[21] Members of the isolated population of O. catharus from the Chatham Islands tend to be larger and take longer to mature than those in mainland New Zealand.[39][67] The following cladogram shows the relationship between O. catharus and the other extant species of Ovalipes:[68][f]

Ovalipes
     
     

Ovalipes georgei

     
     
     
     
     

Ovalipes australiensis

     

Ovalipes punctatus

     

Ovalipes elongatus

     

Ovalipes trimaculatus

     

Ovalipes catharus

     
     
     
     
     

Ovalipes ocellatus

     

Ovalipes stephensoni

     

Ovalipes floridanus

     
     

Ovalipes iridescens

     

Ovalipes molleri


Distribution and habitat

[edit]

Ovalipes catharus is native to New Zealand, where it can be found from Stewart Island to Northland and in the Chatham Islands.[9][25] They are also uncommon on the southern coast of Australia, where they are known as far west as the state of South Australia and as far east as Port Phillip Bay in Victoria.[7][8][40] They live along sandy-bottomed coastal waters, generally at depths of <10 m (33 ft) in estuaries and the subtidal zone,[69][38][70] and they move into the intertidal zone during the evening or the night in order to feed.[11] They are typically buried under the sediment during the day.[14] Although they generally stick to shallow waters, they can be found at depths of up to 100 m (330 ft),[71] and their larvae can be found in deeper waters, up to at least 700 m (2,300 ft).[67] Males and females aggregate in sheltered bays during the winter breeding season.[72] Afterward, males move into large, open beaches in spring, while females migrate to yet-unknown areas – speculated to be deeper spawning grounds for egg incubation.[73] Anecdotal information suggests a substantial population increase since the 1970s.[11]

Diet

[edit]
The off-white shell of a lone specimen of Paphies australis sitting on a background of grey pebbles
Bivalves such as Paphies australis are a significant portion of the paddle crab's diet.[12]

The diet of paddle crabs consists predominantly of molluscs (especially of genus Paphies), crustaceans, fishes, bristle worms, and algae.[74][11][75] Large Ovalipes catharus tend to feed less frequently but generally on algae as well as on larger animals such as decapods and teleosts, while smaller ones prey frequently on smaller, softer crustaceans such as amphipods, isopods, mysids, and cumaceans.[76] They frequently cannibalise smaller conspecifics and those that have recently moulted during winter.[77][78] They tend to eat more during the summer than during the winter.[55][56]

The flattened hind legs and streamlined body shape of the crab allow them to swim rapidly and catch faster prey,[25][14] and they have slender, tapered chelae which are well-suited to handling small molluscs.[31] Their chelae are dimorphic; the left is used for cutting while the right is used for crushing.[28] The paddles also allow the crab to stabilise itself and balance on its third pair of walking legs when digging bivalve prey out of the sand.[79]

Predators and other interactions

[edit]
A video of Ovalipes catharus retreating backward into loose, pebbly sand on the seabed, fully covering itself from back to front over a period of 6.5 seconds. The video is shot from the front at an angle of about 45 degrees to the right relative to where the crab is facing. Brownish seaweed is visible in the foreground of the shot.
O. catharus burrow in the seabed to escape predation.[14]

Predators of the paddle crab include spiny dogfish,[80] snapper (Pagrus auratus),[14] rig (Mustelus lenticulatus),[81] groper (Polyprion oxygeneios),[14] Hector's dolphin,[82] and the invasive crab species Charybdis japonica.[83] Younger individuals are prone to being cannibalised, and all paddle crabs are vulnerable to cannibalism during moulting.[77] Commercial fisheries additionally target the paddle crab.[84] In order to escape predation, Ovalipes catharus creates temporary burrows in soft sand using their paddles, taking only several seconds on average to completely submerge itself.[85] It rests horizontally under about 10–20 mm (0.39–0.79 in) of sand, sometimes leaving its eyestalks poking out.[33]

Ovalipes catharus does not appear to be typically parasitised by nematodes or barnacles.[86] Instead, the overwhelming majority of them[g] are hosts to the ctenosome bryozoan Triticella capsularis, which forms a fur of up to almost 10 mm (0.4 in) thick on their underside after their final moult.[87][86] It is only found on O. catharus,[87] and it is speculated to be an obligate symbiont of the crab.[88] O. catharus does not appear to be affected by parasites present in the invasive C. japonica, which tends to be sympatric with the paddle crab and is heavily parasitised by serpulids.[70] Ecologists have raised concerns that, as C. japonica continues to expand its range, it could outcompete O. catharus with its similar size and diet, some overlap in habitat, high aggression, ability to best O. catharus in one-on-one competition for food, and – due to global warming – its better thermal tolerance.[19][89][90]

Mating and reproduction

[edit]

Ovalipes catharus undergo a pubertal moult at a carapace width of about 40 mm (1.6 in) in males and about 30–40 mm (1.2–1.6 in) in females.[91] They reach sexual maturity within the first year of benthic life, and females produce batches of eggs from early spring to late summer.[92][93] It is not known how many batches can be fertilised from one insemination, but females have been observed to produce up to four or five without re-mating.[94][95] In one batch, the female crabs produce between 82,000 and 683,000 eggs, but like in other crabs, a proportion of these are lost to disease, egg failure, and predation.[96] Number of eggs per batch is also strongly correlated with carapace width and body mass, with larger and heavier crabs having more.[97] Larvae develop synchronously and are released in large numbers through vigorous waving of the female's body, which disturbs their egg cases and causes them to break out.[98] Females generally release their larvae at night.[99] When releasing, they extend their legs to position themselves as far above the seafloor as possible.[99] They then angle themselves slightly upward and begin flexing their abdomen to release large clouds of larvae.[99] Warmer temperatures extend the breeding season, accelerate growth, and lead to earlier sexual maturity.[72] This causes differences in mating times between populations of O. catharus living at different locations in the wild.[100]

Mating behaviours

[edit]
A perspective looking out from a sandy, brownish-grey beach (covered in to the dark pebbles to the left and smooth to the right) toward the somewhat-distant mouth of the bay, which is flanked on either side by peninsulas. The left is steep and lightly forested, while the right is shallow and bald except for grass. Very weak waves wash up onto the shore.
During winter, O. catharus meet in sheltered bays such as Little Akaloa for breeding.[72]

Males and females meet in shallow sheltered bays during winter when the water temperature is ~15 °C (59 °F).[72][101] The time is also variable between populations, with some mating as early as May and as late as November.[102] In response to male competition near a receptive female, males become aggressive and communicate using sounds, although it is unknown if these are directed toward the female, the competing males, or both.[103] It alternates between two sounds: a multi-pulse, low-mid frequency "zip" sound – created by rubbing the ridges on the underside of its chelae against a plectrum-like joint on its first walking legs; and a series of sub-bass vibrations – accompanied by periodic swaying but produced by a yet-unknown internal mechanism.[104] The zip is accompanied by what may be a courtship display whereby the crab "walks forward and flicks both swimming paddles in a twisting motion."[61]

In the shallow bays, the male mates within a four-day window of the female's moult.[98][h] Males can only mate with soft, post-moult females, so they begin to carry a female crab under their body for up to 8 days prior to the female's moult.[105] Once the female has moulted, the male protects her, and they will mate for between 12 and 36 hours and even up to four days.[97] After mating, the female is released and moves on to spawning grounds in what are likely deeper waters.[72] The females of a group may spawn at the same time or asynchronously throughout the season depending on their location.[11] This generally occurs from November to March.[102]

Males of O. catharus sometimes practice sexual cannibalism toward females.[13] This occurs when the female is soft-shelled and therefore vulnerable after moulting.[13] Male crabs generally protect the females during mating, but afterward, the female is vulnerable to cannibalism by other males or, less commonly, by her partner.[13] In one example, male crabs that had not cannibalised females readily accepted food, while those that had engaged in cannibalism rarely did.[106] Size was not shown to have an effect on whether cannibalism occurred.[106]

Relation to humans

[edit]

Ovalipes catharus is a common motif in Māori art, with designs being incorporated into weaving patterns, tā moko, and the designs of wharenui and whare wānanga (houses of learning). The crabs are known to be a traditional food source, but researchers in the early Colonial period did not record much about harvesting traditions.[20]

Commercial fisheries have targeted paddle crabs since the late 1970s, mostly to the east of the North Island and the north of the South Island.[107][108] Catch is sold both locally in New Zealand and overseas to Japan.[109][i] The paddle crab is known for having meat with both good flavour and texture.[111][112] The amount of paddle crabs landed generally increased until the late 1990s, reaching a peak at 519 t (1,144,000 lb) in 1998–1999, at which point it began generally decreasing for the next two decades, reaching an average of 16.6 t (37,000 lb) annually from the five-year period of 2017–2022.[113] Whereas the majority of catch in the 1990s and 2000s came from the east coast of North Island and the west coast of South Island, this declined steeply in the 2010s, and catch in the 2020s has so far come almost exclusively from the east coast of South Island.[108][114]

They are known for their aggression on beaches, often pinching swimmers in New Zealand.[20][7]

Notes

[edit]
  1. ^ Sometimes "New Zealand paddle crab"[2][3]
  2. ^ Sometimes "common swimming crab"[4]
  3. ^ This is disputed as potentially a statistical quirk.[30]
  4. ^ Some sources exclude the rear paddles as walking legs and refer to them independently,[32] while others treat them as the last pair of walking legs.[33]
  5. ^ This subgroup – one of two – is distinguished from the rest of Ovalipes by features such as short chelipeds, large teeth to either side of the front of its carapace, and a triangular last segment of the male abdomen.[64]
  6. ^ Ovalipes itself sits within the monogeneric family Ovalipidae.[6]
  7. ^ 97.4% of O. catharus surveyed from six sites were hosts to Triticella capsularis.[86]
  8. ^ After four days, the female's carapace becomes too hardened to mate.[98]
  9. ^ In 1984, research was conducted into exporting to the United States, which had previously failed due to spoilage and lack of market interest.[110]

References

[edit]
  1. ^ a b De Grave, Sammy (10 April 2022). "Ovalipes catharus (White in White & Doubleday, 1843)". WoRMS. World Register of Marine Species. Retrieved 28 October 2024.
  2. ^ Flood, Goeritz & Radford 2019, p. 1.
  3. ^ Haddon 1994, p. 1.
  4. ^ a b Ahyong, Shane T. (29 April 2010). "Summer Series 2: Cannibals of the seashore". NIWA. Retrieved 29 November 2024.
  5. ^ a b Moorfield, John C. "pāpaka". Te Aka Māori Dictionary. Retrieved 5 March 2022.
  6. ^ a b Poore, Gary C.B.; Ahyong, Shane T. (2023). Marine Decapod Crustacea: A Guide to Families and Genera of the World. CRC Press. pp. 695–696. doi:10.1071/9781486311798. ISBN 978-1-4863-1178-1. LCCN 2021388782.
  7. ^ a b c d e f g h i Wilkens, Serena L.; Ahyong, Shane T. (2015). Coastal Crabs: A Guide to the Crabs of New Zealand (PDF) (First ed.). NIWA. p. 43.
  8. ^ a b O'Hara, Tim; Barmby, Victoria (May 2000). Victorian Marine Species of Conservation Concern: Molluscs, Echinoderms and Decapod Crustaceans (Report). Victoria Department of Natural Resources and Environment. p. 45. ISBN 0-7311-4561-5 – via ResearchGate.
  9. ^ a b McLay 1988, p. 200.
  10. ^ Wear & Haddon 1987, p. 39, 41.
  11. ^ a b c d e f Fisheries New Zealand 2023, p. 1038.
  12. ^ a b Wear & Haddon 1987, p. 40.
  13. ^ a b c d Haddon 1995, p. 256.
  14. ^ a b c d e f g h McLay & Osborne 1985, p. 125.
  15. ^ Haddon 1994, p. 331.
  16. ^ Osborne 1987, p. 84–86.
  17. ^ Fisheries New Zealand 2023, p. 1035.
  18. ^ Fisheries New Zealanad 2023, p. 1038.
  19. ^ a b Fowler, Muirhead & Taylor 2013, p. 672.
  20. ^ a b c Vennell, Robert (5 October 2022). Secrets of the Sea: The Story of New Zealand's Native Sea Creatures. HarperCollins Publishers Ltd. pp. 78–83. ISBN 978-1-77554-179-0. LCCN 2021388548. Wikidata Q114871191.
  21. ^ a b c d e f Stephenson & Rees 1968, p. 225.
  22. ^ a b White, Adam; Doubleday, Edward (1843). "List of Annulose Animals hitherto recorded as found in New Zealand, with the Descriptions of some New Species". In Dieffenbach, Ernest (ed.). Travels in New Zealand; with Contributions to the Geography, Geology, Botany, and Natural History of that Country. Vol. II. John Murray. p. 265 – via the Internet Archive.
  23. ^ Naylor, John R.; Webber, W. Richard; Booth, John D. (2005). A guide to common offshore crabs in New Zealand waters (PDF) (Report). New Zealand Aquatic Environment and Biodiversity Report. New Zealand Ministry of Fisheries. p. 24. ISSN 1176-9440.
  24. ^ Stephenson & Rees 1968, p. 226–227.
  25. ^ a b c d Osborne 1987, p. 3.
  26. ^ Parker, Mckenzie & Ahyong 1998, p. 861.
  27. ^ Parker, Mckenzie & Ahyong 1998, p. 862.
  28. ^ a b Davidson 1986, p. 285, 295.
  29. ^ a b c Davidson & Marsden 1987, p. 308.
  30. ^ Clayton 1990, p. 285.
  31. ^ a b Davidson 1986, p. 295.
  32. ^ Davidson & Taylor 1995, p. 608.
  33. ^ a b McLay & Osborne 1985, p. 126.
  34. ^ Stephenson & Rees 1968, p. 225–226.
  35. ^ "Biology and Ecology of Ovalipes catharus" (worksheet). Bay of Plenty Polytechnic. p. 1. Archived from the original on 20 August 2011. Adapted from “Form 7 Biology Animal Study” by Paul Furneaux of Otumoetai College.{{cite web}}: CS1 maint: postscript (link)
  36. ^ Davidson 1994, p. 4.
  37. ^ Osborne 1987, p. 55–56.
  38. ^ a b McLay 1988, p. 202.
  39. ^ a b McLay 1988, p. 203.
  40. ^ a b c d Wear, Robert G.; Fielder, Donald R. (1985). The marine fauna of New Zealand: Larvae of Brachyura (Crustacea, Decapoda). New Zealand Oceanographic Institute Memoir 92. pp. 50–52. ISBN 0-477-06722-0. ISSN 0083-7903 – via the Internet Archive.
  41. ^ Osborne 1987, p. 1–2.
  42. ^ Richards 1992, p. 48.
  43. ^ Davidson & Taylor 1995, p. 607–608.
  44. ^ Davidson & Taylor 1995, p. 607.
  45. ^ Davidson & Taylor 1995, p. 605–606.
  46. ^ a b Davidson & Taylor 1995, p. 611.
  47. ^ Davidson & Taylor 1995, p. 611–612, 621.
  48. ^ Davidson & Taylor 1995, p. 612.
  49. ^ a b c Iftikar, MacDonald & Hickey 2010, p. 236.
  50. ^ Osborne 1987, p. 91–93.
  51. ^ Iftikar, MacDonald & Hickey 2010, p. 233–234.
  52. ^ Iftikar, MacDonald & Hickey 2010, p. 234.
  53. ^ Iftikar, MacDonald & Hickey 2010, p. 236–237.
  54. ^ Osborne 1987, p. 90.
  55. ^ a b Haddon & Wear 1987, p. 63.
  56. ^ a b Fenton et al. 2024, p. 92–93.
  57. ^ Radford, Tay & Goeritz 2016, p. 1.
  58. ^ Radford, Tay & Goeritz 2016, p. 1–2.
  59. ^ Radford, Tay & Goeritz 2016, p. 1, 6.
  60. ^ Flood, Goeritz & Radford 2019, p. 8–10.
  61. ^ a b Flood, Goeritz & Radford 2019, p. 11.
  62. ^ Stephenson & Rees 1968, p. 224.
  63. ^ Stephenson & Rees 1968, p. 214, 245.
  64. ^ Stephenson et al.
  65. ^ Stephenson & Rees 1968, p. 227.
  66. ^ Glaessner 1960, p. 34.
  67. ^ a b Fisheries New Zealand 2023, p. 1039.
  68. ^ Parker, Mckenzie & Ahyong 1998, p. 866.
  69. ^ Gust & Inglis, p. 349.
  70. ^ a b Miller, Inglis & Poulin, p. 369.
  71. ^ Gust & Inglis 2006, p. 349.
  72. ^ a b c d e Osborne 1987, p. 137.
  73. ^ Osborne 1987, p. 80, 84–86.
  74. ^ Wear & Haddon 1987, p. 41.
  75. ^ Davidson 1987, p. 29.
  76. ^ Osborne 1987, p. 118.
  77. ^ a b Wear & Haddon 1987, p. 47–48.
  78. ^ Osborne 1987, p. 81.
  79. ^ McLay & Osborne 1985, p. 129.
  80. ^ Hanchet 1991, p. 317.
  81. ^ King & Clark 1984, p. 32.
  82. ^ Miller et al. 2012, p. 7.
  83. ^ Fowler, Muirhead & Taylor 2013, p. 678.
  84. ^ Fisheries New Zealand 2023, p. 1033.
  85. ^ McLay & Osborne 1985, p. 127.
  86. ^ a b c Miller, Inglis & Poulin, p. 373.
  87. ^ a b Gordon & Wear 1999, p. 373.
  88. ^ Miller, Inglis & Poulin, p. 372.
  89. ^ Hilliam & Tuck 2023, p. 2.
  90. ^ Iftikar, MacDonald & Hickey 2010, p. 232.
  91. ^ Davidson & Marsden 1987, p. 313.
  92. ^ Armstrong 1988, p. 534.
  93. ^ Osborne 1987, p. 124.
  94. ^ Osborne 1987, p. 125–126.
  95. ^ Haddon & Wear 1993, p. 287.
  96. ^ Haddon 1994, p. 330, 333.
  97. ^ a b Haddon 1994, p. 329.
  98. ^ a b c Haddon 1994, p. 333.
  99. ^ a b c Haddon 1994, p. 332.
  100. ^ Osborne 1987, p. 120.
  101. ^ Iftikar, MacDonald & Hickey 2010, p. 233.
  102. ^ a b Osborne 1987, p. 60.
  103. ^ Flood, Goeritz & Radford 2019, p. 12.
  104. ^ Flood, Goeritz & Radford 2019, p. 7, 11.
  105. ^ Haddon 1994, p. 331, 333.
  106. ^ a b Haddon 1995, p. 257.
  107. ^ Osborne 1987, p. 3–4.
  108. ^ a b Fisheries New Zealand 2023, p. 1033–1034.
  109. ^ Jester, Rhodes & Beuzenberg 2009, p. 369.
  110. ^ Murray, Cameron (1984). "Promising export potential for paddle crabs [Ovalipes catharus]". Catch. 11 (9): 8. ISSN 0110-1722.
  111. ^ Osborne 1987, p. 4.
  112. ^ McLay 1988, p. 208.
  113. ^ Fisheries New Zealand 2023, p. 1033, 1035.
  114. ^ Pierre, Johanna P.; How, Jason R.; Dunn, Alistair (22 August 2022). Whale entanglements with New Zealand pot fisheries: characterisation and opportunities for management (PDF) (Report). New Zealand Department of Conservation. pp. 34–35. Retrieved 28 November 2024.

Bibliography

[edit]
[edit]