Spatial dispersion of ichthyoplankton on Southeastern and Southern Brazilian shelves

Abstract

The physical–chemical and environmental characteristics of the oceans have the greatest influence on ichthyoplankton. Possible environmental changes affect their structure, determining their abundance and distribution. In this sense, it sought to understand the larval distribution processes, which can provide better manhandling and conservation of the fishery resources of the Southern region of Brazil, from the analysis of the larvae belonging to the families Bregmacerotidae, Myctophidae, Sciaenidae, Sternoptychidae, and Trichiuridae, using the temperature, salinity, and depth variables. The data were collected in the Southeastern and Southern Continental Shelves of Brazil between 1970 and 2010 and partitioned using an agglomerative hierarchical clustering algorithm. Four groups were identified, Group I presented a heterogeneous structure and differentiated itself from the rest. It is evident that Groups I and IV predominated in the shallower water and areas closer to the coast, while Groups II and III represented deeper and further waters, within the maximum depth limit of the platforms. Trichiuridae were distributed throughout the clusters, evidencing their easy acclimation to the different temperatures and salinities found. The temperature and salinity presented a greater influence on the larval distribution for these families, corresponding to the coastal dynamics and intrusion of the different water masses over the past 40 years.