Spotlight on: Onykia (formerly Moroteuthis) ingens

Discussion in 'Onychoteuthidae' started by Tintenfisch, Nov 24, 2003.

  1. Tintenfisch

    Tintenfisch Architeuthis Staff Member Moderator

    Joined:
    Nov 19, 2002
    Messages:
    2,079
    Likes Received:
    168
    One of the onychoteuthid species I am strudying at the moment is Moroteuthis ingens. We have a pretty good collection of specimens from New Zealand, and had an additional lot of frozens come in from the Tangaroa recently, so I thought I'd share some background info and photos.

    INTRODUCTION
    Moroteuthis ingens Smith, 1881 is a large-bodied onychoteuthid (personally examined specimens to 450 mm dorsal mantle length (DML); Clarke (1966) estimates a possible maximum DML of 940 mm) found in Sub-Antarctic waters and believed to have circumpolar distribution (Sands et al. 2003). It plays a significant role in pelagic and demersal ecosystems, being a voracious predator and itself prey to at least four species of mammal, 17 species of bird, 13 species of fish, one other species of squid and its own conspecifics (Jackson 1998). Its biology was poorly understood until the early 1990s, but within the past decade a variety of studies, focusing on diet (Phillips et al. 2001, 2003, Jackson et al. 1998), growth (Jackson 1993, 1997), reproduction (Jackson & Mladenov 1994), distribution (Jackson et al. 1998a, 2000), and prey status (Jackson et al. 2000a) have been undertaken to remedy its relative obscurity.

    HISTORICAL RESUME
    Smith (1881) described Onychoteuthis ingens from a large head and brachial crown collected during H.M.S. Alert’s survey of the Magellan Strait and Patagonian coast. At that time, the only other onychoteuthid described from the region was Onychoteuthis fusiformis Gabb, 1862, later synonymised with Oncyhoteuthis banksii (fide Adam 1952: 77). Based on its dermal sculpture, Pfeffer (1900) transferred O. ingens to the genus Moroteuthis Verrill, 1976, and subsequently (1908) assigned it its own genus, Moroteuthopsis Pfeffer, 1908, to differentiate it from Moroteuthis robusta. He later suggested (1912) Moroteuthopsis should be a subgenus of Moroteuthis. However, Kubodera et al. (1998) dismiss Moroteuthopsis in light of the more recently described species Moroteuthis robsoni, Moroteuthis loennbergii, and Moroteuthis knipovitchi, which comprise a spectrum of intermediate morphologies between Moroteuthis ingens and Moroteuthis robusta.
    The first specimen attributed to M. ingens from New Zealand waters was recorded in 1911 (Massy 1916) (however, since this is a strikingly tropical record for a sub-Antarctic species, the identification is dubious (O'Shea, pers. comm.)). The species received relatively little attention through most of the 20th century, but within the last decade, studies on a number of aspects of its biology have made it perhaps one of the best-documented and understood local demersal squid species.
    Bonnaud et al. (1998) addressed the molecular relationships within the family Onychoteuthidae (summarised uncritically here), and determined M. ingens to be to be most closely related to M. robsoni and M. robusta. ‘M. aequatorialis Thiele, 1920’ and ‘M. pacifica Okutani, 1983’, designated a nomen nudum and considered a junior synonym of M. robsoni respectively by Kubodera et al. 1998, and M. robusta (fide Nesis 1987; Tsuchiya & Okutani 1991) also fell within this group (although the specimen attributed to M. robusta (sourced from New Zealand) was not actually referable to this species, but was rather a new species (O’Shea pers. comm.)). Interestingly, Bonnaud et al. suggest that both M. aequatorialis and M. pacifica might be morphological variants of M. ingens, as ‘Kubodera et al. (1998) suggest.’

    BIOLOGY
    A number of recent papers have addressed the life history and biology of M. ingens, particularly spawning and reproductive strategies (Jackson & Mladenov 1994; Jackson 2001) and diet (Phillips et al. 2001, 2003). The larva has also been briefly described and illustrated (O’Shea et al. in prep). A summary follows of the current understanding of the life cycle and biology of Moroteuthis ingens.

    Distribution. M. ingens is a sub-Antarctic species, possibly circumpolar although relatively little sampling has occurred over deep areas (Sands et al. 2003). Populations are recognised off New Zealand and around Macquarie Island, Heard Island, east and west of Patagonia (Xavier et al. 1999) and around the South Orkneys (Clarke 1966). There is some evidence for genetic mixing among these populations, although adult migration of this magnitude is unlikely; mixing probably stems from egg or larval dispersal via jet-stream currents (Sands et al. 2003).
    Based on trawl sampling and interpretation of statolith zones, juveniles appear to lead a shallow pelagic existence for the first third to half of their lifespan, then migrate into deeper waters (Jackson 1993).
    Adults occur over continental shelves (Jackson et al. 2000), 95–420 m in the south Atlantic (Jackson et al. 1998a), and to depths greater than 1500 m in the south Pacific (Jackson et al. 1997, 2000). The Falkland Island population appears to be closely associated with the continental shelf bottom (100–300 m), moving offshore to deeper waters at the onset of the breeding season. The New Zealand population appears demersal, with the highest biomass concentration at 750–800 m (Jackson et al. 1998) and mature females in particular prevalent in waters deeper than 740 m (Jackson 2001); mature males do not appear to follow a particular depth pattern (Jackson 1997).
    Sampling of M. ingens has by and large been restricted to commercial fisheries bycatch over continental shelves (Sands et al. 2003) and specimens taken from the stomachs of predators, so those populations recognised to date may only represent part of the species’ true distribution.

    Growth. The egg masses of M. ingens are currently unknown, but average egg size in mature females is 2.1 mm (Jackson 2001), indicating that the hatching larvae will be relatively large and precocious.
    Larvae of 4.6 mm DML and greater have been recorded from the surface waters off the west coast of New Zealand’s South Island (O’Shea et al. pers. comm.). As captive observations indicate the larvae prefer to feed on prey 100–150 % of their own size (predominantly mysid shrimp and fish larvae) (O’Shea pers. comm.), it is thought that they dwell in the surface layers until attaining sizes where suitable prey can no longer be found.
    Juvenile and immature M. ingens (through ML ~ 200 mm) are known from depths of 500–700 m and feed primarily upon crustaceans (Jackson et al. 1998).
    Males mature at smaller sizes (from DML 204 mm) (Jackson 1997) than females (from 370 mm) (Jackson 2001), and earlier in the breeding season; at times when mature and spent females are sampled, they dominate the demographic, with males being scarce and those few sampled being spent (Jackson 1997, Phillips et al. 2001, 2003). Females’ average growth rate throughout their life cycle, which is linear, is approximately twice that of males, and they weigh approximately five times as much at full maturity as their male counterparts (Jackson 1997).
    Degeneration of tissue occurs in both sexes with the onset of maturity, although it is much more severe in females. Late mature and spent males exhibit a slackened consistency of the mantle tissue, ‘emaciated’ tentacles, and much reduced (from their peak mature state) ribbon-like testes (Jackson & Mladenov 1994, Jackson 2001). The mantles of mature females undergo even more extreme degeneration, and the gonads regress from their mature state (weighing > 400 g in all mature females, and 200 mm) crustaceans occur only in 2.3% of stomachs and cephalopods and teleost fish become the primary prey. Interestingly, other small prey items (e.g. small fish) still occur in gut contents throughout the animal’s life cycle; thus the accessibility of larger prey as M. ingens grows does not preclude the continued utilisation of smaller prey (Phillips et al. 2003).
    Phillips et al. (2001) report that adult M. ingens around Macquarie and Heard Islands prey upon at least 12 species of myctophid fishes (identification of additional species being complicated by the lack of eye lenses or otoliths, indicating that M. ingens may preferentially avoid consuming fish heads). Teleost fish appear to make up the majority of the diet in this region; squid were also common (occurring in 47% of stomachs) but only 2.4% of stomach caeca contained squid flesh exclusively. Adult M. ingens feeding in New Zealand also feed on at least four myctophid species (different from those prevalent in the diet of adults from the regions discussed above), as well as other teleosts. Animals examined from this region appeared to prefer preying upon many (up to 100 in a single feeding period) small fish (< 100 mm) to fewer large ones, consuming the entire small fish (including head) (Jackson et al. 1998). M. ingens from the Falklands Islands also demonstrated a tendency toward cannibalism, with cephalopods comprising the primary prey in 31.8% of gut contents examined. 17.4% of examined specimens contained the remains of conspecifics (Jackson et al. 1998), with one single individual containing the remains of 14 others (Phillips et al. 2003).
    Some concern has been raised over the accuracy of natural dietary studies in trawl-caught specimens, as the squid may have been feeding in nets prior to capture, giving artificial results. However, studies examining chemical composition within the digestive system as a means of assessing diet, or in addition to visual identification of contents, (e.g. fatty acid and lipid analyses) are unlikely to be biased by immediately pre-capture feeding, as the fresh prey items have different chemical compositions from the surrounding digestive fluid and other gut contents (Phillips et al. 2001).
    M. ingens may consume in excess of 10% of its body weight daily (Phillips et al. 2001), making it a significant predator in sub-Antarctic ecosystems. Rodhouse & White (1995) suggest that squid may even replace fish as the major nektonic predator in some areas; as commercial fisheries continue to deplete local large-bodied fish stocks, one would expect this to be increasingly true.

    REFERENCES
    Adam, W. 1952. Cephalopodes. Expedition Oceanographique Belge dans les Eaux Cotieres Africaines de l'Atlantique Sud (1948-1949), Resultats scientifiques, 3(3):1-142.

    Appellöf, A. 1891. Teuthologische Beiträge, II: Chaunoteuthis n.g. Oegopsidarium. Bergens Museums Årsberetning, 1890(1): 29 pp.

    Bonnaud, L.; Rodhouse, P.G.; Boucher-Rodoni, R. 1998. A Phylogenetic Study of the Squid Family Onychoteuthidae (Cephalopod: Oegopsida). Proceedings of the Royal Society of London 265: 1761–1770.

    Clarke, M. 1966. A review of the systematics and ecology of oceanic squids. Advances in Marine Biology 4: 91–300.

    Clarke, M.R. 1980. Cephalopoda in the diet of sperm whales of the southern hemisphere and their bearing on sperm whale biology. Discovery Reports 37: 324 pp.

    Jackson, G.D. 1993. Growth Zones within the Statolith Microstructure of the Deepwater Squid Moroteuthis ingens (Cephalopoda: Onychoteuthidae): Evidence for a Habitat Shift? Canadian Journal of Fisheries and Aquatic Science 50: 1–9.

    Jackson, G.D. 1997. Age, growth and maturation of the deepwater squid Moroteuthis ingens (Cephalopoda: Onychoteuthidae) in New Zealand waters. Polar Biology 17: 268–274.

    Jackson, G.D. 2001. Confirmation of winter spawning of Moroteuthis ingens (Cephalopoda: Onychoteuthidae) in the Chatham Rise of New Zealand. Polar Biology 24: 97–100.

    Jackson, G.D., George, M.J.A.; Buxton, N.G. 1998a. Distribution and abundance of the squid Moroteuthis ingens (Cephalopoda: Onychoteuthidae) in the Falkland Islands region of the South Atlantic. Polar Biology 20: 161–169.

    Jackson, G. D.; McKinnon, J. F.; Lalas, C.; Ardern, R.; Buxton, N. G. 1998. Food spectrum of the deepwater squid Moroteuthis ingens (Cephalopoda: Onychoteuthidae) in New Zealand Waters. Polar Biology 20: 56–65.

    Jackson, G.D.; Mladenov, P.V. 1994. Terminal spawning in the deepwater squid Moroteuthis ingens (Cephalopoda: Onychoteuthidae). Journal of Zoology, London 234: 189–201.

    Jackson, G.D.; Shaw, A.G.P; Lalas, C. 2000. Distribution and biomass of two squid species off southern New Zealand: Nototodarus sloanii and Moroteuthis ingens. Polar Biology 23: 699–705.

    Kubodera, T.; Piatkowski, U.; Okutani, T. & Clarke, M.R. 1998. Taxonomy and Zoogeography of the Family Onychoteuthidae (Cephalopoda: Oegopsida). Smithsonian Contributions to Zoology 586(2): 277–291.

    Mangold, K. 1987. Reproduction. In: Boyle, P.R. (ed.) 1987. Cephalopod Life Cycles 2: 157–200.

    Murata, M.; Ishii, M.; Osako, M. 1982. Some information on copulation of the oceanic squid Onychoteuthis borealijaponicus Okada. Bulletin of the Japanese Society of Scientific Fisheries, 48(3): 351–354.

    Massy, A.L. 1916. British Antarctic (‘Terra Nova’) Expedition, 1910. Natural History Report. Mollusca. Part II.-- Cephalopoda. Zoology 2(7): 141–176.

    Nesis, K.N. 1987. Cephalopods of the world (English translation). Tropical Fish Hobbyist (T.F.H.) publications, Neptune City. 352 pp.

    Okutani, T.; Ida, H. 1986. Rare and Interesting Squid in Japan – IX. A Mass Occurrence of Chaunoteuthis mollis Appellöf, 1891 (Oegopsida: Onychoteuthidae) from off Japan. Venus (Japanese Journal of Malacology) 45(1): 53–60.

    Pfeffer, G. 1900. Synopsis der oegopsiden Cephalopoden. Mitteilungen aus dem Naturhistorischen Museum Hamburg, 17(2): 147–198.

    Pfeffer, G. 1908. Cephalopoden. Brandt & Apstein, Nordisches Plankton 9: 9–116, 120 figs.

    Pfeffer, G. 1912. Results of the Plankton Expedition of the Humboldt Foundation Vol. 2 F.a., The Cephalopoda of the Plankton Expedition [English Translation]. Smithsonian Institution Libraries and the National Science Foundation, Washington, D.C. 618 pp.

    Phillips, K.L.; Jackson, G.D.; Nichols, P.D. 2001. Predation on myctophids by the squid Moroteuthis ingens around Macquarie and Heard Islands: stomach contents and fatty acid analysis. Marine Ecology Progress Series 215: 179–189.

    Phillips, K.L.; Nichols, P.D.; Jackson, G.D. 2003. Size-related dietary changes in the squid Moroteuthis ingens at the Falkland Islands: stomach contents and fatty-acid analyses. Polar Biology, 26(7): 474–485.

    Rodhouse, P.G.; White, M.G. 1995. Cephalopods occupy the ecological niche of epipelagic fish in the Antarctic Polar Frontal Zone. Biological Bulletin 189: 77–80.

    Sands, C.J.; Jarman, S.N.; Jackson, G.D. 2003. Genetic differentiation in the squid Moroteuthis ingens inferred from RAPD analysis. Polar Biology 26: 166–170.

    Tsuchiya, K.; Okutani, T. 1991. Growth Stages of Moroteuthis robusta (Verrill, 1881) with the Re-evaluation of the Genus. Bulletin of Marine Science, 49(1/2): 137–147.

    Xavier, J.C.; Rodhouse, P.G.; Trathan, P.N.; Wood, A.G. 1999. A geographical information system atlas of cephalopod distribution in the Southern Ocean. Antarctic Science 11: 61–62.

    [​IMG]

    [​IMG]

    [​IMG]
     
  2. Jean

    Jean Colossal Squid Supporter

    Joined:
    Nov 19, 2002
    Messages:
    4,215
    Likes Received:
    133
    Location:
    Dunedin, New Zealand
    Interesting stuff Kat! Quite an ontogentic change in shape there. I'd only seen very nearly mature to spent individuals. Great summary! have you looked at the gut contents of any of your specimens? I'm interested to know if you found anything odd..............one of ours had shark skin in the gut, which is unknown as a prey item in cephs, did you find anything like that??


    The spent ones are neat, ever had a squid with a mantle length> 400mm ooze through your fingers :yuck: ??..............That was my intro to whole squid (before that I looked at statoliths!!) Of course being a masochist that made me want to work with MORE squid!! Cockles seemed so bland after that!

    Cheers
    J
     
  3. um...

    um... Architeuthis Supporter

    Joined:
    Sep 5, 2003
    Messages:
    1,968
    Likes Received:
    0
    That's a bit more informative than the TOL's page. Thanks, Kat.

    More.
     
  4. um...

    um... Architeuthis Supporter

    Joined:
    Sep 5, 2003
    Messages:
    1,968
    Likes Received:
    0
    Almost forgot the :notworth:.
     
  5. Phil

    Phil Colossal Squid Supporter Registered

    Joined:
    Nov 19, 2002
    Messages:
    3,034
    Likes Received:
    16
    Thank you for this TTF. Very interesting reading. :notworth: Brilliant!

    Could this be added as a reference article, with even more pictures, do you think?
     
  6. joel_ang

    joel_ang Architeuthis Registered

    Joined:
    May 15, 2003
    Messages:
    2,028
    Likes Received:
    0
    I was wondering Kat, how do u guys identify different squid larva, they all look pretty much the same, if judging only by pics, I would have guessed it belonged to some cuttlefish.
     
  7. Phil

    Phil Colossal Squid Supporter Registered

    Joined:
    Nov 19, 2002
    Messages:
    3,034
    Likes Received:
    16
    A very good question! That's one I've been meaning to ask for ages myself.
     
  8. joel_ang

    joel_ang Architeuthis Registered

    Joined:
    May 15, 2003
    Messages:
    2,028
    Likes Received:
    0
    I forgot, thnx for sharing those nice photos Kat!! :)
     
  9. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

    Joined:
    Nov 19, 2002
    Messages:
    4,668
    Likes Received:
    17
    A bit of work has been done on this in the past. Initially it was by process of elimination; this has been adequate for differentiating genera of onychoteuthid (Onychoteuthis, Notonykia/Ancistroteuthis [a few problems here; we're not saying that they are synonyms at all, just that there's a bit of work required to accurately differentiate them], Moroteuthis etc.), and we followed this up with DNA sequencing. We know for sure what larval morphologies can be attributed to Onychoteuthis 'banksii', Ancistroteuthis/Notonykia sp, and Moroteuthis ingens, but not yet for M. robsoni.

    I'm probably being a little naughty using the generic name 'Moroteuthis', as the TOL refers all Moroteuthis species to Onykia; call it force of habit or precaution rather than us having information to the contrary.

    How one differentiates larval M. ingens from M. robsoni (and yet another indeterminate species in NZ waters) on morphological grounds has yet to be determined, if in fact it can be done. There are a number of 'varieties' of Moroteuthis larvae in the collections - some slender, some stumpy (like the typical Onykia form), and these could prove to be separate species (and the larvae of particular Moroteuthis species); they could equally prove to be different preservation/fixation-induced morphologies. Nothing is certain at present; it's part of Kat's research project.

    Me
     
  10. monty

    monty Colossal Squid Staff Member Supporter

    Joined:
    Mar 8, 2004
    Messages:
    4,887
    Likes Received:
    11
  11. Tintenfisch

    Tintenfisch Architeuthis Staff Member Moderator

    Joined:
    Nov 19, 2002
    Messages:
    2,079
    Likes Received:
    168
    Yes - so very, very many reasons to be glad not to be a squid. :roll:
     
  12. baldtankman

    baldtankman Wonderpus Supporter

    Joined:
    May 5, 2008
    Messages:
    184
    Likes Received:
    0
    Ahem, are the sequences avaliable on Genbank by any chance?

    Just to play with... (I know, get a life Mark)
     

Share This Page