Category: Fish

A fish is any aquatic vertebrate animal that is covered with scales, and equipped with two sets of paired fins and several unpaired fins. Most fish are “cold-blooded”, or ectothermic, allowing their body temperatures to vary as ambient temperatures change.

A natural monument of Kochi Prefecture:Tosakingyo

by S. Takahashi

Introduction

Nishiki, Tosa (Tosa Kyn) is a natural monument of Kochi. It was bred around Kochi-city, Kochi, and It was old, and the history has been already bred in the Edo era. However, It was endangered by war damage and south seas great earthquake disaster (1946), but it is said that Nishiki, Tosa of several of them which survived is the current cause. Nishiki, Tosa (Tosa Kyn) is a natural monument of Kochi. It usually is called “Nishiki, Tosa fish” without calling it the money of Tosa, and the lover is called the Queen of the goldfish from the beauty. Similarly with “IDUMO of Shimane Nanjing” of a goldfish authorized as a natural monument of the prefectures, “metal (six scales) of Aichi”, It is famous as 3 Japanese earth goldfishs.

Discription&Taxonomy

It is one of the kinds of the goldfish, it is established as a kind originally in a country (Kochi-city) of Tosa, and Tosa goldfish is a pure domestic production goldfish conveyed in now．It is the Meiji era that Nishiki, Tosa fish was established as a kind. The construction in an overhanging style repeats improvement from the thing which crossbred strong “goldfish” and “Osaka Ranchu” of the tension of the outer rib in Mr. Suka Taro Kame of the Sugas (1856 through 1937) more, and it is said to a near goldfish that It fixed it in a current figure. From “a goldfish” and mating of “Osaka Ranchu”, It draw a form and essence that It is such original, and is beautiful, and it may be said that it is artistic sensitivity of Mr. Suka Taro Kame and a crystal of the efforts besides to fix. But the Nishiki, Tosa fish at that time was slightly different from the current Nishiki, Tosa fish and seemed to be the figure called “the shrimp tail” which the both ends of the outer rib of the tail projected into forward.

Range & Ecology

The figure is near to a goldfish; egg-shaped, but good goldfish has a refined impression particularly is thin, and to have a sharp it from the eyes to the lips.So the swimming is unhurried, and the figure right and left can shake a soft tail, and to dance elegantly is compared to the flower of the peony by the figure.

There is the color of the body with red, red white (printed cotton), white, gold. But very much in comparison with other goldfish oddity (fading:) Because body color) is slow, the thing which is black in the pro-fish more than three years is not rare. In late years it is flow gold mating in a part and crosses such as the thing which the inversion of the tail is weak, and fading is remarkable, and is early or the money of Kyariko Tosa are seen, but It divide it with these definitely and am treated particularly to be different for a kind at all.

And from what was promoted in Kochi-city of the southern country, It has constitution resisting a high temperature very. In addition, on the other hand, can endure even low temperature of the winter season as the surface of the water freezes like other goldfishs. It is said that like alkalescence of the pH 8 degree about the quality of the water.

Viewing

We can see the “Tosakin” in the aquarium Kochi.

Oncorhynchus masou

by　M. Hattori

Introduction

Oncorhynchus keta have various lifestyles. They are born in the river and live off the coast. After that they go back to the river they born. We can see them sometimes but they have different form and color. So people call them various names. For example, Tokisirazu, Ginke and Hocchare in Hokkaido.

Oncorhychus masou is species of Oncorhychus keta.

Description & Taxonomy

Oncorhychus masou can grow to 50 meters, 300g~1kg weight and live for one or two years. In the river, they eat plankton and insects that live in the water whereas off the coast, they eat plankton and small fish.

Oncorhychus masou belong to Oncorhychus. Other species are Oncorhychus masou masou, Oncorhychus kisutsh and so on. Oncorhychus masou have cinnabar red dot in the back but Oncorhychus masou masou don’t. Oncorhychus kisutsh’s active scope is larger than Oncorhychus masou’s.

Range & Ecology

Oncorhychus masou live in clean rivers and off the coast. The female lives in the river and off the coast whereas a male lives only river. We can see them in the pacific west of Kanagawa, Shikoku and Kyusyu.

Oncorhychus masou move to coast from river. They spawn in September to November and in December to January the eggs hatch. In fall their body changes to silver and move to the coast. After they live off coast for a year, they go back the river. Finally they spawn in their native place.
Use & Conservation

Oncorhychus masou are a semidangerd species. So we must protect their habitat. For that we can reduce garbage in the river.

There are many Oncorhychus masou’s recipe. For example sashimi, grill with salt, bake with salt and so on.

Viewing

If we would like to see Oncorhychus masou, we can see them at Shimanto river and Niyodo river.

Ginbuna: Carassius langsdorfii

Carassius langsdorfii (Ginbuna)

Carassius langsdorfii is a fresh water fish which grows to about 30 centimeters in 4 to 5 years. Carassius langsdorfii belongs Carassius, Carassius of Cyprinidae, it is belongs Cypriniformes, Cypriniformes of Osteichthyes. Almost all Japanese people called them “Ginbuna”, few people call them “mabuna”. Carassius langsdorfii total length is 15 to 30 centimeters. Carassius rangsdorfii’s body get narrow at back of starting buttock fin. “fubunkinanjo” is 4 , “bunkinanjo” is 15 to 18 at dorsal fin. “fubunkinanjo” is 3, “bunkinanjo” is 5 at buttock fin.

Carassius langsdorfii usually grows in Japanese river where flow is mild. Carassius langsdorfii live in ponds and lower of rivers. Carassius langsdorfii is omnivorous fish, for example they eat zoo plankton adhesion seaweed and water animals that live in bottom. The other,

Carassius langsdorfii eats killifish.

Breeding or spawning on be water-weed in spring. But Carassius langdorfii’s reproduction is divided two types, one is asexual reproduction the other is sexual reproduction. Carassius langsdofii is mostly female. It is a kind of asexual reproduction. First, female Carassius langsdorfii produce her coulomb. Afterward, coulomb grows up and goes through this reproduction. But, Carassius langsdorfii’s sexual reproduction is special too. First, female Carassius langsdorfii

blows egg. Then, male Carassius spray sperm. For example, Carassius buergeri subsp called “kinbuna”, Carassius auratus subsp< called “nagabuna” and Carassius buergeri grandoculis called “nigorobuna”are included in Carassius. Afterward, Carassius langdorfii’s female flies are born and grow up. When do Carassius langdorfii

Carassius langsdorfii are used in cultivation with carp in reservoirs and a follow fields in Ueta-city, Toumi city and Saku-city in Nagano. Lately, Carassius langsdorfii are not used for food too. But, at present, Carassius langsdorfii are used for food in Hachirougata-town in Akita. Carassius langsdorfii’s source is Tone-river in Chiba, Biwa-lake in Shiga and so on. Main recipe is roastsd fish sprinkled with salt, “kanro-ni”, soup and sashimi. But, it must not be eaten as is saw, because Carassius langsdorfii is Intermediate host of Gnathostoma spinigerum. There are local specialties called “funamiso” in Aichi and Gifu. Besides, there are local specialties called “funameshi” in Okayama. Carassius langsdorfii is plain taste. Besides, local specialties called “teppai” in Kagawa. Carassius langsdorfii

is a popular fish for sport fishermen.

Carassius langsdorfii is a very interesting fish because, Carassius langsdorfii is almost all female. We can see Carassius langsdorfii at Kitagawa-town, Ino-town, Kahoku-town, Noichi-town in Kochi. We can see Carassius langsdorfii at kochi in October for April. Asexual reproduction occurs almost exclusively in single-celled organism, but Carassius langsdorfii is one of the creatures that do asexual reploduction. What’s more, Carassius langsdorfii do sexual reproduction too. It is wonderful. Carassius langsdorfii are eaten various regions.

Carassius rangsdorfii are loved in various region in Japan. Carassius langsdorfii do asexual reproduction. But there are one problem that problem is speciation. Asexual reproduction equal no-change fly’s character. So Crassius langsdorfii can’t manage for change of nature. It is disadvantage at reflection of species. It’s interesting to see Carassius langsdorfii.

Akame: Lates japonicus

There are different Japanese names for this species: Mehikari in Tokusima, Minouo in Kochi, Maruka in Miyazaki , and Kawanube in Shibusi bay, located southern of Kyushu in Japan.

The mature fish sizes are about 1m over and body colors are silver overall but its back is ash brown. The fish species are the biggest of all freshwater fish in Japan. The size of the largest Akame in Japan is 1m37cm and weight is 30kg. The fish body colors become beautifully black in all when getting excited. The Lates japonicus have long second buttock fin. The fish under jaw protrudes more than the maxilla. The first fin is thorn fin and second fin is flexible fin and buttock fin is thorn fin. Because of light reflection, the fish eyes shines. Because light reflects as for the color of blood, the eyes are red, so the fish Japanese name is Akame. The young fish colors are black brown and there are some yellow and white stripe and point on the head and body. The fish have white meat. The fish face near the lateolabrax japonicus but young fish of Akame tolls are toller than young fish of lateolabrax japonicus.

The fish taxonomy are kingdom-Animalia and phylum-Chordata and class-Actinopterygii and order- Perciformes and family-Latidae and genus-Lates and species-L.japonicus. The scientific name is Lates japonicus Katayama et Taki, 1984. There are one family and one genus and one species in Japan. Family-Latidaes compose three genus and eleven species in Africa and India. Related species of Lates japonicus are Lates calcarifer and Lates niloticus and Psammoperca waigiensis.

The mature fish inhabit shallow ocean and occasionally inhabit the mouth of rivers and bays in brackish water range.

The fish range is the black stream and Pacific Ocean side of Japan. The fish is an endemic species. Mainly the fish can see in Kochi and Miyazaki.

The fish are an oviparous animal and carnivorous animal. They eat small fish and shrimp and crab. The mature fish eat carp about 30cm. The fish come in to lay from June to August. The young fish are about 4mm. The young fish come to the mouth of a river from spring to autumn and inhabit Zostera marina place. They grow until about 10cm and body becomes black and white stripes. Shortly afterward, they leave the mouth of a river. But it doesn’t know whether the fish lay eggs in river or sea. The fish come to mouth of a river, because a parasite adheres to the fish body by osmotic pressure. The fish are in Red Data Book, because the range of inhabit is narrow and the fish is small populations. The fish are NT in Tokushima, DD in Ehime, and CR in Kochi in Red Date Book.

The fish is best to see in Summer season in Urado bay,Kochi,. But recently Urado bay in Kochi is contaminated, so the fish are decreasing. So you may be able to see them in Shimanto River in summer rather than Urado bay in summer. The fish can frequently be seen in Shimanto River when the water level of the river after rain goes up. The fish can be seen in the Kasturahama aquarium.

Ayu: Plecoglossus altivelis altivelis

In summer, if you go to upper reaches of a river, you may see many anglers who have very long fishing rods. Probably, they are Ayu fishing. Ayu is famous in Japan. Most Japanese know Ayu live clean rivers at least.

Ayu have many relations. First, we eat Ayu. For esample, Sioyaki, Tempura, Segosi, Sabazusi and Uruka. But Ayu may have parasitic which are called Yokogawakyuutyuu. So if you eat Ayu, you should not eat it raw. In addition to this, it is Ayu fishing. There are caught by decoy and fry-fishing. But there are closed season for fishing from May to November and we must buy license fishing. And goods are very expensive.

Ayu’s scientific name is Plecoglossus altivelis altivelis. They belong to Osmeriformes like smelt and Japanese smelt. They are related to koukakugyorui.

Ayu fry live in sea and downriver. They eat plankton and insect which live or fall in the water. They hatch from two weeks and they are clear in body so we can their beating heart and air bladder. When they become ten millimeters, they begin to be fragrant like watermelon or Oriental melon. On April and May, they get color and the teeth become like spit. And they go up river.

Adult Ayu live in middle and upper reaches of rivers and eat algae. They are gray and green. Young Ayu swim together but bigger Ayu make territory in places where there are many diatom. This territory is one meter in every direction and if others enter the territory, they deliver an attack by bodily impact. In fall, they become orange and black. It is nuptial coloration. From February to September they swim down river. Then they lay eggs in shallows where there are many pebble stones and sand in group and die. So they end their lifetimes in one year.

Much Ayu live in Kochi rivers because Kochi’s river are clean. Rivers which Ayu live in Kochi are Shimanto River, Yoshino River, Niyodo River, Monobe River and Kagami River. So if you are interested in Ayu, go to the upper reaches of a river and fish Ayu.

Ayu have a relation with people from old times. But wild Ayu are decreasing by people impact. Ayu cannot live in muddy rivers because algae cannot photosynthesize in muddy rivers. Releasing Ayu into the river is done in Japan. It is good thing. But I don’t like this because it may mix alien species and origin. So I think we must keep clean river. If wild Ayu are not seen river, it is very lonely.

Hirame: Japanese flatfish

The Japanese flatfish, or Olive flounder, is a kind of the fish that belongs to the large tooth flounder suborder of the flatfish family. Its scientific name is Paralichthys olivaceus. The two eyes show it is lying on its right side with both eyes on the the left side.

Moreover, it has a feature that the mouth and teeth are big. It is distributed in the Pacific Ocean west (From the coast in the Kurile Islands, karahuto, Japan, and a Korean peninsula, etc. to the South China Sea). The flatfish grows to 1m in total length and about 10kg in weight in the maximum. The flatfish figure has both as right and left side types.

The flatfish lives in sands and the mud lake in the coast at night. It often conceals itself in sand and mud, only the head has been put out in daytime, and the color of the body is made the same color as bottom of the sea when not diving in sand.

The flatfish eats the fingerling, shellfishes, and the mussel worms that live chiefly at the bottom of the sea. The flatfish dives deeply in winter. And, it goes to the shoal of about 20cm in depth for the spawning time from March to July.

The egg is a floatage. The child was born from the egg is lucky also with normal eyes as long and slender as a usual fish. The movement of right eyes starts by about 1cm in the total length. It becomes the same type as parents when becoming about 2.5cm. It becomes an adult fish in about three years. Flatfish’s longevity is short for about several years.

The flatfish is high grade ingredients used for slices of raw fish and the sushi in Japan. Moreover, growth is quick, and geostationary at the bottom of the sea. Therefore, because oxygen is not very needed and seawater not made dirty, cultivation is active. It will be expected to circulate by a further low price considering the cultivation cost in the future.

The individual that doesn’t reach a certain size is discharged again for the resource conservation, and the discharge of the fry is done. The flatfish into which the fry is released doesn’t disappear by the pattern that the belly side is black even if growing up, and is called pandabirame. There are a lot of people who insists on the domination of the natural product who insist that the momentum at food influences the eating quality. The season of the flatfish is winter. It is said that the summer time after eggs is laid loses taste.

The flatfish is best seen in the Niyodo river in Kochi Prefecture.

Jimbeizame: Whale Shark

There are so many sea animals on Earth, for example, fishes and mammal. Rhincodon typus is the biggest of fishes on earth. It is called a Whale shark in English.

In Kaiyukan, Osaka

It is a most body length of about 13.7m and width of about 1.5m. The figure is a spindle-shaped, flat head and the teeth are 300 to 350. The skin tissue is thick, and the thickness is about 10cm. Tail fin of the adult are usually crescents. However tail fin of the young does not stand out the lower part, and have the feature with large only upper part. The color is light yellow into white check in body, is white in stomach but without stomach, is ultra marine. Marking of the whale shark is seen personality each individual. It is so useful to individual recognition when we observe. The whale shark is very timid and a quiet-looking. It acts basically alone however rarely by the flock. Female of the whale sharks tend to stay in a specific sea area, on the other hand male of them wander a wide sea area.

Genus name is Rhincodon and species name is typus. Rhincodon typus was classified and described by Andrew Smith biologist British based on the specimen captured in the Table Bay in Cape Town in South Africa in April, 1828. It is guessed that Rhincodon typus was born 60 million years ago.

Whale sharks live in a subtropical, tropical, temperate zone in the surface sea area around the world and wander. They are seen also in the vicinity of the mouth of river, a lagoon, a coral reef and among bays.

The whale shark makes small ecosystem. Why can this be said? Whale sharks are filter feeding and eat plankton. Small fishes also are eating it. Medium fishes flock for eating small fishes. Large migratory fishes flock for eating medium fishes. Namely, the whale shark forms a small ecosystem by one individual. People thought that it was a lucky of good catch between fishermen. So, Japanese does not eat it. But it is said that the whale shark had been decreased enough to put on the Red List of endangered species. Because a developing people that suffer from a food shortage hunts excessively. Once it had been believed that the whale shark was oviparous. But it was turn out that it was viviparous in 1995. After the spawn hatches in the interior of the womb, the fry is given birth while having grown up from 40 to 60cm. It matures in about 30 years and lives at about age of 70. We do not know breeding of the whale shark much. But we know that their propagating power is low. And today it is said that the protection of the whale shark is important. Otherwise, it might be exterminated.

We can see the whale shark in Ashizuri Cape in Kochi. It wanders to Tosashimizu from June to September. Or always are able to see it at Kaiyukan in Osaka, Tyuraumi Aquarium in Okinawa and Iburi center in Tosasimizu. In Iburi center, the living thing to exhibit in Kaiyukan is collected, bred and the surveillance study of the surrounding ocean area is done.

Skipjack Tuna

Skipjack tuna is the English name. Japanese name is katuo. And scientific name is Katsuwonus pelamis. And there are seasonal Japanese namea, that for example is modorigatuo and kudarigatuo. The Skipjack tuna is designated as Kochi prefecture’s fish.

Skipjack tuna is eaten as tataki and sashimi in Kochi. And pole-and-line fishing of Skipjack tuna in Kochi is famous. And also raw Skipjack tuna in Kochi is very famous all over the country.

Skipjack tuna can grow to a body length of 1m of large size and to a body weight 18kg. Its form is spindle-shaped that has low hydrodynamic drag. Section is nearly ring shape.

Skipjack tuna belong to katuwonus of scombridae of scombroidei of perciformes of actinoptergii of vertebrate of chordate of animalia.

There are some varieties of scombridae; the striped bonito (Sarda orientalis), the Skipjack tuna (Katuwonus pelamis), the kawakawa (Euthynnus affinis).

Striped bonito is smaller than Skipjack tuna, but has a lot more of teeth than skipjack tuna, and also back color is different each other. Striped bonito’s color is blue, but Skipjack tuna’s color is deep indigo. The kawakawa, which range at over a large area of the tropical zone subtropical zone of the Indian Ocean, is heavier and has bigger withers weight than Skipjack tuna.

Skipjack tuna’s rage is the temperate zone and the tropical zone area of sea all over the world. ;It exists between the north latitude of 40° and the south latitude 40°of the equator’s both sides. Skipjack tuna visit each the Pacific Ocean side to the south of Hokkaido and Kyushu west coast at Japan. Skipjack tuna’ rage is very large, so discovery skipjack tuna’s migration course is very difficult.

As the above-mentioned, Skipjack tuna is living at temperate and tropical zone. This reason is that Skipjack tuna had a liking for water temperature 17~30°. Principally Skipjack tuna swim by school at sea surface of coast confine.

Skipjack tuna’s back body color is deep indigo and abdominal color is silver white of plain. This back and abdominal color is defense method to so-called counter shadowing. In that connection let me say that a lateral stripe come up to the abdominal when it is excited, and when it die , a vertical stripe and disappear a lateral stripe rise up to the abdominal.

Skipjack tuna is flesh-eating fish. They eat small size fish, crustaceans and cephalopoda. And they are migratory species of fish, so they move during the season, in other words, they goes up north in summer and go down south in autumn.

Usually Skipjack tuna swim at 25~50 kilometers an hour, and at times they swim about 100 kilometers an hour. But they die when they stop swimming. The reason is that skipjack tuna get a lot of oxygen from gills while they swim at high speed. So they experience oxygen shortage when they stop. Skipjack tuna stand higher rank of food chain, but t hey make large school so-called nagura, and play group action.

Skipjack tuna migrate along the Japan Current, so we can see at open sea of the Pacific Ocean (the Japan Current,) in early in summer to autumn in Kochi.