Freshwater fishes maintain multi-trait phenotypic stability across an environmental gradient in aqueous calcium

Reductions in a limiting nutrient might be expected to necessitate compromises in the functional traits that depend on that nutrient; yet populations existing in locations with low levels of such nutrients often do not show the expected degradation of functional traits. Indeed, we previously found that fish of three species, Logperch (Percina caprodes),Pumpkinseed Sunfish (Lepomis gibbosus), and Yellow Perch (Perca flavescens) residing in low-calcium water in the Upper St. Lawrence River nevertheless maintained levels of scale calcium comparable to those of conspecific populations in high-calcium water. However, it remains possible that the maintenance of one functional trait under nutrient-limited conditions could come at the expense of maintaining other functional traits that depend on that same nutrient. Hence, we here extend prior work by examining other calcium-dependent traits: skeletal element sizes and bone densities in the same fish species in the same area. Using radiographs o..., ,