Temporal and spatial variations in the growth of 0 group roach (Rutilus rutilus) in the River Great Ouse, in relation to water temperature and food availability

✍ Scribed by Mann, R. H. K.

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 188 KB
• Volume: 13
• Category: Article
• ISSN: 0886-9375
• DOI: 10.1002/(sici)1099-1646(199705)13:3<277::aid-rrr455>3.0.co;2-7

✦ Synopsis

In the River Great Ouse, a highly ¯ow-regulated lowland river in eastern England, the most common cyprinid ®sh, roach (Rutilus rutilus), showed marked variations in growth both between years and between sites. Growth rates were highest at the most downstream sites and also in a large marina into which many 0 group roach migrated in midsummer. Between-year differences in growth rates in early summer were not always associated with parallel deviations in water temperature (degree days b 12 C). Instead, variations in prey (zooplankton) abundance may also in¯uence the initial growth rates of roach larvae. A switch in the diet of 0 group roach in late June from small invertebrates (Cladocera, Chironomidae larvae, etc.) to one dominated by detrital aufwuchs may explain the discrepancies between observed growth rates and those predicted from a temperature growth model.