Recruitment dynamics and life history aspects of striped mojarra, Eugerres plumieri, in Lake Maracaibo, Venezuela

Background/Question/Methods
Although striped mojarra has been an important commercial fishery resource in coastal lagoons in tropical areas; e.g., Terminos Lagoon, Mexico, Cienaga Grande de Santa Marta, Colombia, and Tacarigua Lagoon, Venezuela, in Lake Maracaibo this species was until recently mainly used as bait in the crab pot fishery; few people indeed consumed striped mojarra. However, a moderate but increasing artisanal fishery of striped mojarra has developed in the last few years in western Venezuela, including the Lake Maracaibo basin. Any perception that the striped mojarra is an irrelevant fishery resource is changing rapidly. The increasing diminishing in the catch of traditional commercial fish species and the concomitant increasing in their prices, are encouraging an increasing demand of fish species formerly considered of second category as the striped mojarra. Thus, my objectives here were to: 1) Examine recruitment and abundance dynamics of striped mojarra in Lake Maracaibo to evaluate the potential effects of anthropogenic habitat alterations, which can be seen as an ecological objective; and 2) Evaluate basic life history aspects (e.g., growth, reproduction) of striped mojarra, which can be seen as a fishery biology objective.  Sampling was conducted semimonthly from January 2000 to December 2002 using beach seines and cast nets.

Results/Conclusions
Fluctuations in abundance were substantial. The proportion female:male was 1.77:1 (P < 0.05).  Length-weight relations were: W = 0.00000791TL^3.08 (W = weight, TL = total length) for females and W = 0.000175TL^2.47 for males. There were an intense recruitment pulse in April and a minor one in September. Sizes of first sexual maturity were 180 mm TL for females and 170 mm TL for males. Parameters of the von Bertalanffy growth function were: L∞ = 374 mm TL, k = 1.27 year^-1 and t₀ = -0.27 year for females; L∞ = 313 mm TL, k = 1.78 year^-1 and t₀ = -0.46 year for males. Available information suggests that abundance of striped mojarra follows Lake Maracaibo natural periodic tidal-discharge rhythms. Evidence presented in this paper suggests that if either the tidal or the discharge patterns are changed, the whole biota of Lake Maracaibo may be affected. Striped mojarra make up an abundant fish resource that plays important ecological and fishery roles in Lake Maracaibo. Given the increasing fishery importance of striped mojarra, initiatives should be developed to protect its population in Lake Maracaibo.