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BIOMASS AND DENSITY OF BROWN AND RAINBOW TROUT IN NEW MEXICO STREAMS
Srećko Leiner
Sažetak
Mean stream numerical density of the brown trout (Salmo trutta m. fario Linnaeus, 1758) and the rainbow trout (Onchorhynchus mykiss Walbaum, 1792) was 0.090 fish/m2 of which brown trout averaged 69% (72% in total biomass) in 15 high-elevation New Mexico streams (1,661-2,560 m above sea level). Total trout density varied from 0.008/m2 in 1988 and 1989. Mean trout density ranged between 0.023-0.121 fish/m2 at site s open to public fishing. Considerably higher densities (0.142-0.409 fish/m2) were observed at sites closed for fishing. In the seven selected streams shared by both species, brown trout density exceeded rainbow trout density except at the two sites closed to fishing.
Brown trout were stocked only as fingerlings (average 7,000 fish/stream/year) while rainbow trout were stocked only in harvestable sizes (11,000 fish/stream/year). Reported total trout yield rates exceeded the total number of fish estimated to be in the stream by 1.01 to 11.63 in most small streams open to fishing. The proportional stock density (PSD) ranged between O and 50 percent. Streams with low to moderate intensities of fishing had the highest PSD.
Ključne riječi
Salmo trutta m. fario; Onchorhynchus mykiss; density; biomass; streams; New Mexico; management
Hrčak ID:
46263
URI
Datum izdavanja:
30.3.1995.
Posjeta: 1.128 *