Life-history strategies associated to reproduction of three Hyphessobrycon species (Characidae) in lentic environments of upper Paraná River basin

Abstract

AIM: Life-history strategies in fish include essential parameters related to offspring survivorship, fecundity and time of reproduction, which represent adaptive traits that enable a species to deal with spatial and temporal variability of abiotic conditions. This study aimed to compare reproductive traits associated to life-history theory for three Hyphessobrycon species from two lentic environments (four natural oxbow lakes and a man-made reservoir) of Mogi Guaçu River, upper Paraná River basin. METHODS: Specimens were collected with four minnow traps between August 2005 and July 2006 to cover dry and wet seasons (three samples in each season, and three samples in each environment). RESULTS: Reproductive strategy of H. bifasciatus and H. eques, which predominated in the oxbow lakes, differed from H. anisitsi in the reservoir. Hyphessobrycon bifasciatus and H. eques were single spawners with lower fecundity and size at sexual maturity, but invested more in number of eggs per body gram, while H. anisitsi was a multiple spawner species with higher fecundity, larger size at sexual maturity and body size. CONCLUSIONS: In seasonal environments, single spawners are synchronized with the floods to maximize juvenile survivorship, while reservoirs harbors multiple spawners’ fish due to the reduced fluctuation between high and low floods resulting from dam operation. Therefore, the seasonal condition in the oxbow lakes due to the flood pulse favored single spawners’ tactic, as showed by H. bifasciatus and H. eques. In contrast, the multiple spawning of H. anisitsi seems to be related to the more stable environmental condition throughout the year provided by the dam. Life-histories reported herein to Hyphessobrycon species must be common to other characid fishes inhabiting similar environments.

Reproductive biology of Hyphessobrycon eques (Characiformes: Characidae) in Southern Pantanal, Brazil

“…A long reproductive period is common in small species (Hojo et al, 2004), but does not match with the reproductive strategy of seasonal environments (Vazzoler and Menezes, 1992), with short reproductive period associated with the favorable conditions of flood (Tedesco et al, 2008). Different from the results found in this study, in the Paraná River Basin, a short reproductive period was reported for H. eques, which showed reproductive period associated with period of rains (Gonçalves et al, 2013), showing the plasticity in reproductive strategies according to the local conditions.…”

“…The length/weight relationship for H. eques indicated greater increment in weight in function of the similar length between males and females, contradicting the results observed by Gonçalves et al (2013), which highlighted the negative allometric growth for the same species in lentic environments in southeastern Brazil, justified by a greater length reached by H. eques in this environment and by the statistic inverse correlation between maximum size reached by a population and its rate of weight increment (b of LWR).…”

“…However, it is known that the reproductive strategy of a species, among other traits, is the most conservative history of life (Agostinho et al, 1999), so that even in different environmental conditions, the species shows similar patterns in size at first maturation. It is important to note that, even with different average length between the population of H. eques analyzed here and the population observed by Gonçalves et al (2013), the similar L 50 suggests a high growth rate for the population in southern Pantanal as a possible adaptation to high mortality. According to Vazzoler (1996), the rapid reach to L 50 is an efficient mechanism to increase the genetic representation of the population in the next generation.…”

Genetic Applications in the Conservation of Neotropical Freshwater Fish

“…Such attributes are related to the different forms of feeding, life maintenance and reproduction [26][27][28]. Research into the pattern of life strategies may have practical applications in conservation and is fundamental to fishery management in identifying appropriate measures to reduce the impact from reservoirs and other anthropogenic activities [29].…”

“…Such attributes are related to the different forms of feeding, life maintenance and reproduction [26][27][28]. Research into the pattern of life strategies may have practical applications in conservation and is fundamental to fishery management in identifying appropriate measures to reduce the impact from reservoirs and other anthropogenic activities [29].Neotropical fish species range from colonising and opportunist species to periodic and equilibrium species. Colonising populations, such as those belonging to the genera Astyanax and Phalloptychus, mostly require energy for reproduction and are generally represented by small, rapidly maturing and short-lived species.…”