Gymnodraco acuticeps, commonly known as the Plough Fish or Antarctic Dragonfish, is a benthic fish native to the Southern Ocean, particularly around the Antarctic Peninsula. Belonging to the family Nototheniidae, it is highly adapted to survive in the extreme cold of its habitat, typically found at depths ranging from 0 to 550 meters, though it is rarely observed below 50 meters. The name Gymnodraco is derived from the Greek words gymnos (meaning “bare” or “naked”) and draco (meaning “dragon”), which fittingly describe its dragon-like appearance and lack of scales. Its specific epithet, acuticeps, refers to its sharply pointed head, a distinctive feature that aids in identifying the species. This fish exhibits several remarkable adaptations, including antifreeze glycoproteins in its blood that prevent ice crystal formation, allowing it to thrive in subzero waters. As a benthic predator, it feeds on small invertebrates and plays a key role in maintaining the balance of the Antarctic benthic food web.
The ploughfish was first formally described in 1902 by the Belgian-born British ichthyologistGeorge Albert Boulenger with the type locality given as Cape Adare in Antarctica,[1] Boulenger placed this species in a new monotypic genus Gymnodraco, it is still the only known species in that genus.[2] The genus name is a compound of gymnos which means "bare" or "naked", a reference to the almost complete lack of scales on the body, and draco meaning "dragon" and is a common suffix used for notothenioid fish names. The specific nameacuticeps means "pointed head" an allusion to the strongly depressed head with its sharply pointed snout.[3]
Description
The ploughfish has a naked body, the only scales being those on the two lateral lines with the middle lateral line only has perforated scales, which is depressed at the head and compressed towards the tail. The head is triangular in shape with a long, pointed snout. There is a strong ridge on the operculum which forms a spine with a hooked process at its rear end and there is another spine on the soboperclulum and the preoperculum is smooth. The jaws have canine-like teeth at the mandibular symphysis, with bands of small, slightly decurved conical teeth behind them. The lower jaw protrudes beyond the upper with its front canine-like teeth exposed. There are 27-30 soft rays in the dorsal fin and 23-26 in the anal fin. In alcohol the overall colour of the body is dark brown, becoming paler on the underside. The head is marked with small spots and the body with dark blotches, although these may fade over time. The fins are dark brown to blackish and there is a patch of dark colour around the anus.[4] This species attains a maximum total length of 38.5cm (15.2in) and a maximum weight of 86.2g (3.04oz).[5]
Distribution and habitat
Figure 2. Geographic distribution of Gymnodraco acuticeps in the Southern Ocean. The species is primarily found around the Antarctic Peninsula, inhabiting benthic zones in close association with rocky substrates.
The ploughfish is native to the Southern Ocean and has been recorded from the Antarctic Peninsula, South Shetland Islands and the continental shelf of Antarctica, it probably has a circum-Antarctic range. However, as yet, it has not been recorded from West Antarctica. This is a demersal species, it primarily inhabits benthic zones from the surface down to about 0 to 550m (0 to 1,800ft),[5] although it is rare below 50m (160ft).[4] It is often associated with rocky seafloor substrates, which provide both shelter and foraging opportunities, reflecting its adaptations to the cold, high-pressure conditions characteristic of the Antarctic benthic ecosystem.
Diet
Gymnodraco acuticeps is a benthic predator that is primarily piscivorous, feeding on small fish and benthic invertebrates. Its diet includes myctophid fishes such as Electrona antarctica and Gymnoscopelus spp., juvenile nototheniids, amphipods, krill (Euphausia superba), polychaetes, and occasionally fish eggs. The species hunts near the seafloor, utilizing its compressed body and strong operculum to maneuver and capture prey efficiently in the cold Antarctic environment. Through its predatory behavior, G. acuticeps plays a critical role in the Antarctic benthic food web, helping to regulate populations of smaller fish and invertebrates.[6]
Reproduction
Gymnodraco acuticeps exhibits a reproductive strategy characterized by parental care. Spawning results in the deposition of approximately 2,500 benthic eggs on flat rocks. These eggs undergo an extended developmental period of about 10 months at temperatures near −1.9°C, during which they are actively guarded by one or both parents.[7] This prolonged incubation enhances the survival of the offspring in the harsh, cold environment of the Antarctic benthic ecosystem.
Life History
Spawning of Gymnodraco acuticeps occurs primarily in the austral spring, around October, under fast ice in the Ross Sea. Males initiate courtship by prodding the female, followed by a whirling behavior prior to egg deposition. Eggs, approximately 3.42 mm in diameter, are attached to flat rocks on the seafloor and remain there for about 10 months before hatching, with both parents guarding them against predators such as amphipods and other benthic species.[8] Larvae emerge at roughly 12 mm in length, seek shelter under sea ice, and absorb their yolk sac over approximately 15 days. Growth is slow in the cold Antarctic waters, with laboratory observations showing an average daily growth rate of 0.42% over nine weeks. Larvae are highly sensitive to environmental cues, and hatching is often synchronized with the return of sunlight. These life history traits, including delayed development and parental care, represent adaptations to the extreme Antarctic environment, enhancing reproductive success and survival in a habitat with unpredictable food availability.
In Recreation
Gymnodraco acuticeps is not targeted by commercial or recreational fisheries, largely due to its remote Antarctic habitat and relatively small size. However, it is occasionally included in scientific research programs that investigate Antarctic benthic ecosystems and the adaptations of fish to extreme cold. Studies also focus on how warming waters and ocean acidification affect the morphology and physiology of species inhabiting Antarctic environments. Through such research, G. acuticeps provides valuable insights into the resilience and vulnerability of polar marine fauna under changing climatic [9]
Current Magement
There are currently no specific management or conservation measures in place for Gymnodraco acuticeps. Its populations are considered stable, and the species is not listed as endangered or threatened. However, its habitat benefits from partial protection under Antarctic conservation treaties, which regulate fishing activities and limit environmental impacts in the Southern Ocean. These measures indirectly support the conservation of G. acuticeps and other Antarctic benthic species.[10]
↑ 10. ^ Stevens, D. W., Dunn, M. R., Pinkerton, M. H., & Forman, J. S. (2014). Diet of Antarctic toothfish (Dissostichus mawsoni) from the continental slope and oceanic features of the Ross Sea region, Antarctica. Antarctic Science, 26(5), 502–512. https://doi.org/10.1017/s095410201300093x
↑ EVANS, C. W., CZIKO, P., CHENG, C.-H. C., & DEVRIES, A. L. (2005). Spawning behaviour and early development in the naked dragonfish Gymnodraco acuticeps. Antarctic Science, 17(3), 319–327. https://doi.org/10.1017/s0954102005002749
↑ 1. ^ Barrera-Oro, E. R., & Lagger, C. (2010). Egg-guarding behaviour in the Antarctic bathydraconid dragonfish Parachaenichthys charcoti. Polar Biology, 33(11), 1585–1587. https://doi.org/10.1007/s00300-010-0847-3
↑ Flynn, E. E., Bjelde, B. E., Miller, N. A., & Todgham, A. E. (2015). Ocean acidification exerts negative effects during warming conditions in a developing Antarctic fish. Conservation Physiology, 3(1). https://doi.org/10.1093/conphys/cov033
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