Fanray Explained

The fanray (Platyrhina sinensis) is a species of ray in the family Platyrhinidae that lives in the western Pacific Ocean. It typically grows to a length of 30cm–50cmcm (10inches–20inchescm) and a weight of 200g500g, with a brown upperside and a white underside. It eats fish and crustaceans and has poor mobility. Males live to age five and females to age twelve, with both sexes maturing between two and five years. The species is found in China, Japan, Taiwan, Korea, Vietnam, and possibly Indonesia, in waters shallower than 100m (300feet). It is probable that its population is declining due to being caught as a bycatch.

Description

Fanrays grow to a maximum known length of 68cm (27inches),[1] but most specimens are 30cm–50cmcm (10inches–20inchescm) long and weigh 200g500g. Its body is flat throughout and shaped like a fan. The species' upperside is brown in color, its underside white, and the edge of its body yellow. It has wide nostrils, small eyes, a short snout, and a transversal through its mouth splitting it. It has multiple small teeth and thorn-like scales on the upperside of its body.

Behavior

The fanray eats small fish and crustaceans, specifically shrimp and mysids. To feed, it usually stays on the sea floor until there is an opportunity to capture food; it is a nocturnal species. It exhibits oviparity and mates in April or May. It swims slowly, due to the fact that its only way to move is by moving its tail forwards and backwards.

Males have a lifespan of five years, maturing between two and four years, while females have a lifespan of twelve years, maturing between three and five years. Both sexes mature when between 35cm (14inches) and 40cm (20inches) in total length, females at a slightly larger size than males. Specimens at Ariake Bay, the most common area the species occurs in, were surveyed from May 2002 to September 2006 for their age, growth, and sexual maturity. The survey revealed that females grow slower than males but achieve a greater total length as an adult. It also determined that in comparison to other related species, the ray grows and matures quickly, and lives for a short amount of time.[2]

Habitat and distribution

The fanray lives in the western Pacific Ocean in waters up to 100m (300feet) deep, generally between 30m (100feet) and 40m (130feet) in coastal areas with a sandy sea floor. In particular, it is found off the coasts of China, Japan, Taiwan, Korea, Vietnam, and possibly Indonesia. The species is the most abundant elasmobranch species in Ariake Bay, Kyūshū,[3] and is also common in the Yellow Sea and Bohai Sea.

The species is caught as bycatch in gillnets and trawls, sometimes being discarded but other times made use of. However, its population has not been negatively affected by these activities.[3] [2] Its flesh can be eaten fresh or after being dried. Its exact population or population trend is unknown, but its population in the East China Sea is known to be decreasing due to trawling activities. The fact that it lives in shallower waters makes it easy to be caught by fisheries. The species is the most common in several countries in the Northern part of its range. Currently, no conservation actions or restrictions are taking place on behalf of the species. Because of its probable population decline, the IUCN Red List lists it as an endangered species.

Notes and References

  1. Book: Compagno, L.J.V. . Last, P.R. . Platyrhinidae: Thornback rays . Carpenter, K.E. . Niem, V.H. . FAO identification guide for fishery purposes. The living marine resources of the Western Central Pacific . Rome . Food and Agricultural Organization of the United Nations . 1999 . 9251043027.
  2. 10.1111/j.1444-2906.2008.01584.x . Age, growth and age at sexual maturity of fan ray Platyrhina sinensis (Batoidea: Platyrhinidae) in Ariake Bay, Japan . Kume, G. . Furumitsu, K. . Yamaguchi, A. . amp . Fisheries Science . 74 . 4 . August 2008 . 736–742. 2008FisSc..74..736K .
  3. Iwatsuki . Yukio . Nakaya . Kazuhiro . Miyamoto . Kei . Zhang . Jie . A review of the genus Platyrhina (Chondrichthys: Platyrhinidae) from the northwestern Pacific, with descriptions of two new species . . January 2011 . 26–40 .