Critically Endangered
Giant guitarfish
Rhynchobatus djiddensis
Giant guitarfish is a shark or ray in the family Rhinidae (order Rhinopristiformes) — Rhynchobatus djiddensis, recorded as Critically Endangered.
Appearance
A large fish reaching up to 3.1 m (10 ft) long and weighing as much as 227 kg (500 lb), it is brownish or greyish above with a variable pattern of white spots. There is a dark, bar-like pattern between the eyes (on top of the head), that separates it from the other Rhynchobatus species in its range. The species may be confused with the distantly related common shovelnose ray, from that it differs in a smaller first dorsal fin set farther back on the body. A more rounded head with a prominent snout; a lack of upper jaw indentations, and larger skin denticles.
Range and habitat
The giant guitarfish was previously believed to range throughout a large part of the Indo-Pacific, but recent evidence has shown that it, as traditionally defined, actually was a species complex consisting of four different species. With these as separate species, the giant guitarfish has a relatively restricted range. It is found only in the Red Sea and Persian Gulf, and the western Indian Ocean as far south as South Africa. Ranging across the western Indian Ocean, it is common to misidentify the separate species of guitarfish within a similar range.
Additionally, the Indonesian Aru Islands wedgefish gillnet fishery had rapidly expanded their industry from the mid-1970s to its peak in 1987, operating with more than five hundred boats.
Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.
Diet
The giant guitarfish is considered ovoviviparous, where the embryos initially feed on the yolk and then receive more nourishment from uterine fluid enriched with mucus that is obtained by means of indirect absorption.
In crisis
Even though the giant is labeled as critically endangered on the IUCN Red List, there is no specific data for the species that could be used to calculate the number of individuals in the decreasing population. Although there's an insufficient data record kept on the exact giant guitarfish population. The harvest rates infer that the species is substantially decreasing while the fishing rates remain stable or even increase. Shortly afterward, the catch rate of the fish declined significantly and only a hundred boats remained in the area by 1996.
Overall, the collected data is utilized to calculate proportional declines, annual change in population, and the reduction of the giant guitarfishes over the three generations of complementary data. From this dataset, it shows that the landings declined by sixty-six percent over the twenty years, that is approximately ninety-one percent of a population reduction over the last three generations of larger glaucostegid species.
CITES lists this taxon on Appendix II. Confirm the current appendix on the CITES checklist.
Giant guitarfish is Critically Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.
Sources
Written for this catalog from the English Wikipedia article on Giant guitarfish, Wikidata item Q260678. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.
