Fish are cold blooded animals i.e. their body temperature is close to ambient temperature and does not exceed it by more than 0.5. 1 deg. So the speed of metabolism they depend on the water temperature. Only tuna as a result of intensive muscular activity in rapid motion the body temperature may exceed the temperature of water at 10 deg.
From vertebrate fish – the largest group of animals. There are over 20 thousand species – more than the amphibians, reptiles, birds and mammals combined. In the superclass of Jawed (Gnathostomata), which include all fish, from 515 to 550 species belongs to the class of Cartilaginous fish (Chondrichthyes) (chimeras, sharks, rays) and from 19135 until 20980 species to the class of Bony fish (Osteichthyes) (all other fishes, including cartilaginous ganoids – sturgeon and others, which in the adult skeleton presents no spine, and the chord, but there are also bones, mainly covering forming the outer skeleton). In addition, there are about 50 species of lampreys and mixin-jawless fish-like animals, which fish are not. They come in the Cyclostomes (Cyclostomata), belonging to another superclass – Jawless (Agnatha), though are together with fish for the same type of Chordates (Chordata) and subtype Vertebrates (Vertebrata), or Skull (Craniata). About 41.2% of fish are typically freshwater, about 0.6% live in both fresh and salt water (brackish). The remaining 52.2 per cent is marine fish, of which 39.9 per cent live in the coastal waters of warm seas and oceans, 5,6% – in cold coastal waters, 6,4% are deep-sea bottom and bottom-dwelling (benthic) species, 5% of deep-sea pelagic and 1.3% live far from the coast in the upper 200 m of the water column of seas and oceans (epipelagic species). Continue reading
Mammal from the order Cetacea, suborder of toothed whales. In Russia, dolphins are found in waters of the Black, Barents and Baltic seas. Dolphins moving predators that live in groups. They eat fish, mollusks, crustaceans. The dolphins have two jaws with a large number of identical teeth. The animal has a small head with a pointed muzzle. In most individuals there is the dorsal fin. In Russian waters, there are: Atlantic white-sided Dolphin, beaked Dolphin, black sea Afalina.
Atlantic white-sided Dolphin in the waters of our country dwells only in the Barents and Baltic seas. These dolphins prefer warm water, whose temperature varies from 5 to 15°C. they Feed on fish (herring, sand eels, cod, smelt) and cephalopods. In places where there are numerous schools of fish, there are up to thousands of dolphins.
The period of confinement of dolphins falls on may to August. The interval between births is 2 to 3 years. Young individuals are found near the mother for up to 2 years. Females in rare cases, live to be 27 years old, the average age of males is about 20 years. Currently the number of dolphins in Russian waters is not established. The pollution of the seas affects the inhabitants of the seas. Atlantic white-sided Dolphin is listed in Appendix 2 of CITES, Appendix 2 of the Bonn Convention Appendix 2 Berne Convention.
Beaked Dolphin – rare, almost neizuchennyi. He dwells in Russian waters in the Northern and Eastern parts of their range (in the Barents and Baltic seas). Body length is 2.5 – 3 m. the Exact information about the number of this type no. But it is known that beaked Dolphin is often found in the cold waters. Continue reading
Fish enliven the garden pond: for their graceful movements interesting to watch. The role of fish in maintaining the balance of oxygen and carbon dioxide in the water is usually exaggerated, while the benefits they offer by eating mosquito larvae, it is difficult to overestimate. However, the presence of fish in the pond is desirable, but not necessarily, because usually has little effect on the maintenance of the purity of water.
SPECIES OF FISH
When choosing fish are primarily guided by the size of your pond. If you are not strapped for cash, you might want to purchase expensive and beautiful koi. Unfortunately, these fish need special conditions — the surface area of the pond not less than 7.5 m 2 and a depth of at least 1.2 m. At the other end of the scale are hardy and unassuming goldfish and shubun-cytokines, which are able to live in any, even very tiny pond — it is necessary only to ensure that in winter the surface water is not delayed by ice for a long time. Between koi and goldfish is Golden Orff, which required a pond with a surface area of at least 4 m2. Another important consideration is visibility. Motley shubunkin and black telescopes spectacular aquarium, but in a pond they are lost. Better to inhabit a pond of bright — white, yellow, orange and red fish. The most suitable for this is the movable gold zolotarivka and Orpah, because they always stick at the water surface. Continue reading