摘要:

Abstract.In four 0.8‐ha drainable ponds the production, growth, condition and angling vulnerability of zander (15cm). The experiments look place in the period April‐October 1986. The P:Bü ratios of zander in two ponds with an average biomass of forage fish (282 kg) 3.5 times the mean biomass of zander(.80kg), were 0.17 and 0.28. In two ponds with an average biomass of forage fish (38kg) 0.58 times the mean biomass of zander (65 kg), P:Bü ratios were 0.02 and 0.06. The growth and condition responses of individual zander were highly variable within each pond. Effects of sex were not observed on these responses. In June 1986 the angling vulnerability of zander was negatively related with the availability of forage fish. In August‐September 1986 no differences in angling vulnerability were observed between the zander in the four ponds. The male and female zander were equally exploited by anglers. The captures of zander were not related with the size or weight of t

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1991.tb00498.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.The effects of different pre‐stocking feeding levels on the subsequent catchability of rainbow trout, Oncorhynchus mykiss (Walbaum), were investigated in a 12‐ha put‐and‐take fishery. Two sibling batches of Winthrop strain were fed high or low rations of a pelleted diet to produce similar sized, but recently fast‐ and slow‐growing fish. Each batch was given a distinctive dye mark. Anglers’catch records showed that although the 'slow‐growing’fish were significantly the more easy to catch during the first week after stocking, over the remaining 5 months of the fishing season there was little difference in catchability between batches. This suggests that previous observations of sustained between‐strain differences were not the result of selection of fast‐ and slow‐growing fish per se, but were probably

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1991.tb00499.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.During weed‐cutting operations on the River Frome, Dorset, England, cut weed (800t), together with associated macroinvertebrates, was removed at five boom sites down the river. The mean density of macroinvertebrates removed was 30 individuals per g dry weight of cut weed which was equivalent to 6mg dry weight per g of cut weed, ca. 4900 individuals per square metre of river bed, or 0.9g dry wt/m2of river bed.The cut weed removed was populated chiefly by larvae of Chironomidae and Simuliidae although the numbers and biomass ofEphemerella ignitaPoda andBrachycentrus subnubilusCurtis were a significant part of the total macroinvertebrate population.Macroinvertebrates removed on cut weed were estimated as ca. 20% by number and ca. 12% by biomass of the total population from published values. The river (50km) was difficult to sample immediately prior to weed cutting because of rapid changes in the density and position of invertebrate populations, the immense sampling effort required and the non‐synchronous system of cutt

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1991.tb00500.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Multilingual Dictionary of Fish and Fish Products. Prepared by the Organization for Economic Co‐operation and Development.Biology, Epidemiology and Management of Pyro‐dinium Red Tides. Edited by GUSTAAF M. HALLE‐GRAEFF and JAY L. MACLEAN.Principles of Fish Nutrition. By WERNER STE

ISSN:1355-557X    

DOI:10.1111/j.1365-2109.1991.tb00501.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY