Length-Weight Relationship and Condition Factor of Curimata inornata Vari, 1989 in Four Different Water Bodies in the State of Amapá, Brazil

Abstract

The condition factor is an index that indicates the fish welfare status in relation to the environment where it lives and reflects recent nutritional conditions and/or usage of reserves in cyclic activities. It is also possible to relate the condition factor to environmental conditions and to behavioral aspects of the species. The Curimatidae is a family of detritivorous fishes distributed in the Amazon Basin, with species alternating between the upper, middle, and lower Amazon and its tributaries. With the aim of investigating whether different environmental conditions may interfere in any way in the populations of Curimata inornata present in the state of Amapá we used 658 individuals from two quarterly sampling programs. The Vila Nova, Matapi Rivers and the igarapé da Fortaleza were sampled quarterly between March and December 2001 and the Araguari River between November 2011 and March 2013. The length-weight relationship and the condition factor were calculated for each sampling point and for the different seasons of the hydrological cycle of the water bodies. The allometry coefficient values followed an increasing trend in terms of the conservation degree of the rivers under analysis. The condition factor of the individuals showed no correlation with the hydrological regime of the water bodies. Thus, the population structure of C. inornata in the rivers under study was highly impacted by the environmental conservation degree, but the hydrological regime of the water bodies did not influence the population structure. Keywords: Length-weight relationship; condition factor; Curimatidae; Amapá.