. Biology of the seas of the Marine biology -- Soviet Union; Hydrology -- Soviet Union. GENERAL CHARACTERISTICS AND GEOLOGICAL HISTORY 377 distinguish among them two large groups, connected with the thermopathy and halopathy of the corresponding race of fish. Some fish move between zones of small salinity range, keeping always within zones of similar salinities (stenohaline) and during their whole existence living within the boundaries of one body of water; others can survive during their travels considerable changes of salinity (euryhaline) and can pass from one body of water to anot
. Biology of the seas of the Marine biology -- Soviet Union; Hydrology -- Soviet Union. GENERAL CHARACTERISTICS AND GEOLOGICAL HISTORY 377 distinguish among them two large groups, connected with the thermopathy and halopathy of the corresponding race of fish. Some fish move between zones of small salinity range, keeping always within zones of similar salinities (stenohaline) and during their whole existence living within the boundaries of one body of water; others can survive during their travels considerable changes of salinity (euryhaline) and can pass from one body of water to another. The same can be said about temperature conditions—some can only survive limited changes of temperature during the year (stenothermic); others can live through considerable temperature fluctuations (eurythermic). This is illustrated by the diagram in Fig. 182. It is remarkable that Sarda, which populates the eastern part of the Mediter- ranean, moves in the summer to the Black Sea for feeding and Fig. 181. General character of feeding migrations offish (3) in eastern part of Medi- terranean, Black and Azov Seas, contrasted with abundance of plankton (7) (see explanation in text) and with commercial productivity (2) (kg/ha) (Zenkevitch, 1947). This is possibly evidence that the past history of the eastern Mediterranean shoal of Sarda was somewhat exceptional—maybe that its fate was linked during some periods of the Quaternary Period with life in bodies of water of low salinity. A series of most interesting regularities was established by A. Svetovidov (1943, 1948, 1957) in his comparison of the taxonomic com- position, distribution, biology and size of fish in the Azov-Black Sea and Caspian basins. First of all, Caspian pelagic fish are larger than those in the Black and Azov Seas. Caspiolosa brashnikovi, with a length of 20 to 35 cm (C. br. brashnikovi) in the Caspian Sea and 16 to 20 cm (C. br. maeotica) in the Black Sea, can be taken as an example. The long
Size: 2384px × 1048px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionameri, bookcollectionbiodiversity
