摘要:

ABSTRACTThe survival of 0+ brown trout, spray‐marked with fluorescent pigment and stocked in two angling lakes as summerlings and autumn fingerlings, was assessed by netting exercises. About twice as many autumn fingerlings as summerlings survived the first winter after stocking, and in one lake the percentage survival of the two groups was estimated at 31.0% and 15.2% respectively. Survival to age 2+ was estimated to be in the range 5.7–9.7% for summerlings, and from 15.1% to 16.6% for autumn fingerlings. The best survival for both groups was obtained in the most productive lake, where condition factors and growth rates were the highest. The results were assessed in economic terms, and the cost per 2+ fish in each lake was more expensive from both summerling and autumn fingerling stocking than from direct introductions of fish‐farm, two‐year‐

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1984.tb00576.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTThe post‐stocking movements and survival of hatchery‐reared brown trout (Salmo truttaL.) (length 18–19 cm) stocked into depopulated and control stretches of the Afon Clettwr, South Wales, were investigated. Data were obtained from electrofishing surveys and rewarded tag returns.Recapture rates ranged from 67–76% for both stretches. The resident population of wild brown trout had no significant effect on the dispersion of the stocked fish, the majority of which remained close to the point of stocking.No stocked fish were recovered from the experimental stretches in the year following their introduction. Within one year the depopulated stretch had been recolonized by wild trout.The implications upon restocking after a fish kill are di

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1984.tb00577.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTMarked hatchery‐reared smolts were released into the River Bush on the 1 May and 19 May 1980. and the time for their descent to trapping facilities was monitored. Of the smolts recaptured in each experiment 56.2% and 75.8% respectively descended the 3.5 km to the traps within 48 h, and the overall patterns of their downstream movements were found to be correlated to that of wild smolts. Smolts migrating from control tanks did so more slowly than those released into the river, and were not correlated with the movements of wild smolts.The feeding of recaptured hatchery smolts was compared with that of wild smolts for up to 11 days after the start of each experiment. It was found that most invertebrate groupings were not consumed at significantly different levels in the two groups, and that hatchery‐reared fish began feeding on invertebrate food within 9 hours of rele

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1984.tb00578.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1984.tb00579.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1984.tb00580.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1984.tb00581.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY