Length–weight, length–length relationships and length at first maturity of fish species from the Paraná and Uruguay rivers, Argentina

Length–weight relationships (LWR) were estimated for 12 species, representing three orders and eight families of fishes from the Paraná and Uruguay rivers in Argentina: Acestrorhynchus pantaneiro, Cynopotamus argenteus, Pachyurus bonariensis, Pterodoras granulosus, Hypostomus commersoni, Pseudoplatystoma corruscans, Pimelodus maculatus, Parapimelodus valenciennis, Salminus brasiliensis, Prochilodus lineatus, Hoplias malabaricus and Leporinus obtusidens. For the last four species, the length at first spawning (Lₘ) was estimated using three different methods. The captures were made in shallow river areas during 2005–2013. Significant length–weight relationships were found for all species. None or few LWRs were previously available for these species.