Influences of environmental and chemical parameters on the spatial growth patterns of four riverine cyprinid fishes
Understanding intraspecific variability in fish somatic growth rates is important as growth is a key life history trait that plays a fundamental role in many biological and ecological processes. Here, the influence of environmental and chemical parameters was tested on intraspecific variability in growth rates of the cyprinid fishes roach Rutilus rutilus, chub Squalius cephalus and dace Leuciscus leuciscus across 13 rivers in England, and also compared with those for barbel Barbus barbus from the same rivers. Outputs indicated that growth rate responses to the parameters were species-specific, with more significant effects generally detected on juvenile growth than lifetime growth. For R. rutilus and S. cephalus, latitude (as a surrogate of temperature) was the most significant predictor of their growth rates, with growth rates decreasing as latitude increased. Contrary to prediction, aspects of degraded water quality accelerated the growth rates of these fishes, except in B. barbus, although concentrations of nitrogenous compounds were below toxicity thresholds. This emphasizes the ability of populations of these cyprinid fishes to tolerate some environmental disturbances and, in entirety, suggests that the intraspecific variability in the growth rates of these fishes is significantly influenced by abiotic parameters and their association with levels of anthropogenic disturbance.