Great spider crab explained

The great spider crab, Hyas araneus, is a species of crab found in northeast Atlantic waters and the North Sea, usually below the tidal zone.^[1]

In 1986, two specimens were captured at the South Shetland Islands off the Antarctic Peninsula, apparently transported by human agency.^[2] It has been feared that the species would have an adverse effect on the native fauna, but there have been no further captures from the region since the 1986 specimens.^[3]

The great spider crab can moult and get rid of their outer shell/skin. This can take some time but it lets them grow to great size. After they moult they are very vulnerable to predators because of a very soft exoskeleton.

Notes and References

1. Web site: Great spider crab . The Marine Fauna Gallery of Norway . Kåre Telnes. https://web.archive.org/web/20070928031754/http://www.seawater.no/fauna/Leddyr/sandpyntekrabbe.htm. 17 November 2021 . 2007-09-28 . live.
2. Discovery of the first known benthic invasive species in the Southern Ocean: the North Atlantic spider crab Hyas araneus found in the Antarctic Peninsula . Marcos Tavares & Gustavo A. D. de Melo . . 2004 . 16 . 2 . 129–131 . 10.1017/S0954102004001877. 2004AntSc..16..129T . 86753556 .
3. Antarctic Crabs: Invasive or Endurance? . H.J. Griffiths . R.J. Whittle . S.J. Roberts . M. Belchier . K. Linse . . 2013 . 8 . 7 . e66981 . 10.1371/journal.pone.0066981. 23843974 . 3700924 . 2013PLoSO...866981G . free .