1 . Bony fishes inhabit almost every body of water. They are found in tropical, temperate, and polar seas. Bony fishes exist in fresh water, seawater, and brackish environments.
2. Some species of bony fishes live as deep as 11 km (6.8 mi.) in the abyssal oceans. Other species inhabit lakes as high as 5 km (3.1 mi.) above sea level (Lagler, 1962).
3. Approximately 58% (about 13,630) of all species of bony fishes live in marine environments. Although only 0.01 % of the earth's water is fresh water, freshwater fishes make up approximately 42% (about 9,870) of fish species (Wootton, 1990).
4. Some species of bony fishes aren't limited to one particular ecosystem. Diadromous bony fish species migrate between fresh and saline environments.
1. Depending on the species, bony fishes can live at various temperatures. Some live at extreme temperatures.
a. The desert pupfish (Cyprinodon macularius) lives in small hot springs of California. It can tolerate temperatures greater than 520C (126F) (Nikolsky, 1978).
b. At the opposite extreme, some species of bony fishes can survive freezing as long as their body fluids remain unfrozen. The arctic cod (Boreogadus saida) can survive temperatures as low as -2)C (28F) (Nikolsky, 1978).
2. Some bony fishes can tolerate high salinity levels. Seawater has a salinity level averaging 35 ppt (parts per thousand). Some species of gobies can tolerate salinity levels as high as 60 ppt. (Nikolsky, 1978).
3. In general, fishes rely on oxygen dissolved in water for respiration.
a. Some species of bony fishes require large amounts of dissolved oxygen. The brown trout (Salmo trutta) requires up to 11 mg of dissolved oxygen per liter.
b. Misgumus fossilis, a type of loach, can survive in as little as 0.5 mg/l of dissolved oxygen.
c. Mudskippers (family Periophthalmidae) can carry a small amount of water in the gill cavity and commonly spend time on land, returning to mudholes when their water supply begins to evaporate.
4. The lungfish must have access to the water's surface. Lungfish gulp air into a primitive "lung" for respiration.
1 . Most bony fishes have small home ranges.
2. Food and habitat availability, reproduction, environmental cycles, and temperature change may be causes of migration for some species.
3. Some species of bony fishes migrate great distances.
a. Almost all tuna (family Scombridae, tribe Thunnini) species are migratory.
(1) Albacore tuna (Thunnus alalunga) migrate across the Pacific Ocean from the coast of California to the coast of Japan, more than 8,500 km (5,270 mi.). From tagging studies on albacore, researchers have determined that these fish travel an average of 26 km (1 6.1 mi.) per day (Joseph, 1988).
(2) Tagged northern bluefin tuna (Thunnus thynnus) have migrated 7,700 km (4,774 mi.) across the Atlantic Ocean in 119 days, about 65 km (40.3 mi.) per day (Joseph, 1988).
(3) Southernbluefintuna(Thunnusmaccoyii),skipjack(Euthynnuspelamis), and yellowfin tuna (Thunnus albacores) also migrate.
b. Bilifishes (family Istiophoridae) are highly migratory. One tagged black marlin (Makaira indica) was released off Cabo San Lucas, Mexico, and recovered off Norfolk Island in the South Pacific-more than 10,680 km (6,622 mi.) away (Joseph, 1988).
4. Diadromous bony fish species migrate between fresh and marine environments.
a. Catadromous fishes migrate from freshwater environments to the ocean to spawn. The freshwater eels (family Anguillidae) develop in marine environments but move into freshwater rivers to live.
b. Anadromous fishes migrate from marine environments into freshwater environments to spawn. The sockeye salmon (Oncorhynchus nerka) may travel more than 3,600 km (2,232 mi.) up the Yukon River to spawn.
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