By Y. Horisawa
Do you know the biggest salty river fish in Japan?That fish is Japanese lates(Lates japonicus) and his full length is more than 1m. Lates’s eyes are bright red, so Lates is called Akame in Japan. Moreover his color is silver but color of his fry is black. Like this, Lates is odd fish.
Description & Taxonomy
Lates’s length is more than 1m. Biggest ever caught was 138cm and 30kg. His body is silver and is high. But when fry, black color, because it’s protective coloration. His Japanese name is “Akame”, because his eyes bright red.
Lates.japonicus belong to Latidae. This family have three genuses: Hypopterus, psammoperca and lates. Hypopteras has 1 species and inhabits westAustraria. Psammoperca has 1 species and inhabits eastan indian Ocean. Lates have 10 species, and have some endangered species. In fact, Lates is endangered species too.
Nile perch (L. niloticus) is closely related species to Lates. But Nile Perch is not an endangered species, rather they make fish presence felt that is species indigenous to Lake Victoria.
Range & Ecology
Lateses live in Japan only. They live in the western Japan facing Kuroshio. Mainly his range is Miyazaki and Kochi. Lateses lives in coast. But when they are fly, they live in river.
Lates’s frys gather at the estuary. And live there with Koamamo. They eat small fish and shellfish, and protect them from foreign enemy. Adult fish some times are estuary. This is for doing sake that taking off parasite in salty river by low osmotic pressure.
Spawning is not well understood but it is thought spawn in the sea on summer. They act on the night. And their wariness is high, so they intrude estuary at night or rainy time. They are prey, so they eating small fish. They are good target for fishing.
Use & conservation
They grow very big. They are good target for lure fishing. Moreover, we can eat Lates. Their white flesh is very delicious for broild fish with salt and Sashimi.
But, Lateses are an endangered specise. They are banned to fishing in Miyazaki since 2006. This is same deal Nihonkamoshika. Moreover they are regsterd CR in Kochi. Why Lates decrease? Fry’s bed: the place where Koamamo grows is destroyed. For example,by river is maintained or water is pollute. So flys cannot grow, and die. We showld protect Koamamo place.
There is stuffed specimen at Usa Kaiyo Zisshu Shisetsu. It is very big. If you get a chance to go there, do look a stuffed specimen.
Range in Kochi
Lates’s range is the whole of the coast of Tosa gulf.