Abstract

VALDEZ-ZENIL, José et al. Relative abundance, size structure and length-weight relationships of the Mexican Mojarra Eugerres mexicanus. Ecosistemas y recur. agropecuarios [online]. 2015, vol.2, n.6, pp.349-356. ISSN 2007-901X.

The Mexican mojarra Eugerres mexicanus (Steindachner), is a freshwater species with distribution in southeastern of Mexico and northern Guatemala, as well as it is a commercially important species for the artisanal fisheries developed in the area. The relative abundance in density and biomass, length-weight relationships and the relative condition factor were appraised on the basis of specimens caught in the Usumacinta River basin, Municipality of Tenosique, Tabasco (México) during April 2008 to January 2010. A total of 355 specimens, with predominance of females (50.4 %), were collected during the overall study period. Length-weight (L-W) and length-length (L-L) relationships showed good fit for the linear regression for the overall population (r > 0.9766, p < 0.005), with b values between 3.0886 in males to 3.3115 in immature fishes. Student's-t test indicate allometric growth for females (b = 3.1183, t = 2.2835, df = 177, p < 0.001) and inmature fish (b = 3.2672, t = 2.0528, df = 28, p < 0.001), as well as isometric growth for males (b = 3.08860; t = 1.6080, df = 149, p < 0.001). The relative condition factor (Kn) varied from 1.0015 in males, 1.0013 for females and 1.012 for inmature fish. The information reported here will be useful in conservation and fisheries management programs for this endemic Neotropical species.

Keywords : Gerreidae; length-weight relationship; Usumacinta river; Neotropical region; abundance.