Length–weight relations for 19 freshwater fish species (Actinopterygii) from the lowland Elbe River, Germany

Monthly and mean length–weight relations (LWRs) were calculated for 19 freshwater fish species from the middle section of the lowland Elbe River (Germany): Abramis brama (Linnaeus, 1758); Alburnus alburnus (Linnaeus, 1758); Anguilla anguilla (Linnaeus, 1758); Ballerus ballerus (Linnaeus, 1758); Blicca bjoerkna (Linnaeus, 1758); Cobitis taenia Linnaeus, 1758; Esox lucius Linnaeus, 1758; Gobio gobio (Linnaeus, 1758); Gymnocephalus cernua (Linnaeus, 1758); Leuciscus aspius (Linnaeus, 1758); Leuciscus idus (Linnaeus, 1758); Leuciscus leuciscus (Linnaeus, 1758); Lota lota (Linnaeus, 1758); Perca fluviatilis Linnaeus, 1758; Romanogobio albipinnatus (Lukasch, 1933); Rutilus rutilus (Linnaeus, 1758); Sander lucioperca (Linnaeus, 1758); Scardinius erythrophthalmus (Linnaeus, 1758); and Squalius cephalus (Linnaeus, 1758). The values of the exponent b in the LWR W = aTLb ranged from 2.882 (Lota lota) to 3.517 (Cobitis taenia) and the correlation coefficient (r2) was greater than 0.96 for all species except for Cobitis taenia with 0.93. The relations allow for the accurate estimation of weight from length data with reduced handling times of fish in the field while enabling comparisons with other regions and future studies. The calculated LWRs together with species-specific abundance and catch data will be useful for fisheries modeling and estimating population status and related fish species protection, especially for the endangered species in the Elbe River.