Integrated use of otolith shape and microchemistry to assess Genidens barbus fish stock structure

Abstract Otolith composition (edge vs core: Mg/Ca, Mn/Ca, Zn/Ca, Sr/Ca, Ba/Ca) by LA-ICP-MS and Elliptic Fourier analysis were integrated to evaluate spatial segregation of adult and juvenile stages of Genidens barbus from specimens collected from five coastal areas off Brazil (Paraiba do Sul River, Guanabara Bay, Itapanhau River mouth, Paranagua Bay), Argentina and Uruguay (La Plata Estuary). Fisheries of this diadromous catfish have largely collapsed in the southwest Atlantic coastal region due to overexploitation. An understanding of population structure is now critically needed for improved management strategies for this endangered species. PERMANOVA based on otolith edge chemistry showed significant differences (p