摘要:

ABSTRACTThe construction and installation of habitat Improvement structures in a small lowland river are described. Low dams and current deflectors installed were successful in producing pool‐riffle habitat characteristics while artificial cover structures effectively simulated the shelter normally associated with river banks. The Improvement programme was found to partially mitigate the adverse effects on the environment of river channel works carried out at the site to improve land drainage. The role of improvement structures in fishery rehabilitation is discusse

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1982.tb00026.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTAdvance knowledge of flow rate variations in the water supply to a spring‐fed trout farm is of great value to the farm manager since the weight of stock that can be sustained at any one time is dependent on the discharge rate of the spring. Annual variations of flow rate in groundwater dominated streams and rivers follow a fairly regular pattern with a recession occurring from the highest flows in the spring to the lowest flows in the late summer and autumn. This paper describes a simple technique for predicting discharge rates during periods of recession. Use of the technique which is illustrated by data from Belleau springs in Lincolnshire would enable fish farm managers to obtain a conservative estimate of the flows during summer and autumn and give adequate forewarning of impending low flow

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1982.tb00027.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTStock, catch and effort data for a small ‘put‐and‐take’ trout fishery were analysed to determine a stocking strategy fulfilling the needs of both anglers and management. The assumptions of negligible ‘natural’ mortality and constant ‘catchability’ implicit with stock determinations using catch per effort and catch succession techniques were tested, and found to be largely upheld in this instance. The calculations of optimal stocking rates based on these results are described and indicate that frequent restocking with sufficient fish to maintain a stock capable of giving the desired catch per effort is preferable, both from the viewpoint of angler satisfaction and to facilitate management

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1982.tb00028.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTExperiments carried out in hatchery ponds indicated that the survival and tag retention of tagged fish was significantly correlated to their length at tagging. Tag retention in small fish was found to be so low that tagging studies on these in the wild cannot be used to assess angler returns. It was also found that there were significant differences in tagging efficiency between different operators.Experiments were also carried out with tagged trout of four different ages, which were released into an angling lake. The best returns were obtained from spring‐stocked 20‐year old fish, of which 44.8% were recaptured. This was almost three times the reported recaptures of trout of a similar size which had been stocked as autumn 1+ All the recaptures were corrected for mortality and tag loss from the control results, and compared to the findings of previous studies. The results were also discussed in terms of the value of stocking different age classes of trout in relation to angling pressure and angling meth

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1982.tb00029.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Book reviewed in this articleSalmon Ranching by JOHN THORPE (Ed.)Limited Entry as a Fishery Management Tool by R. BRUCE RETTIG and JAY C. GINTER (Eds)Principles of Fishery Science. 2nd Edn by W. H. EVERHART and W. D. YOUNGS

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1982.tb00030.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY