Reproductive ecology of a neotropical cichlid fish, Cichla monoculus (Osteichthyes: Cichlidae)

Abstract

The reproductive ecology of the freshwater fish Cichla monoculus Spix, 1831 (Osteichthyes: Cichlidae) was investigated in the Campo Grande Reservoir, Northeast Brazil. Rainfall, temperature, pH, dissolved oxygen and electrical conductivity of the water were recorded monthly. Fish collected on a monthly basis were measured, weighted, dissected, sexed and the stage of maturation of the gonads were assessed by macro and microscopic means. The semi-arid study region has short spells of rain of 2-3 months duration interspersed with dry seasons. A positive correlation was observed between rainfall and air and water temperatures and conductivity of the water. The study population had an extended spawning season, with peak reproductive activity coinciding with low water temperatures. Males were longer and heavier than females on average and were larger at onset of sexual maturity. The size frequency distributions of the oocytes indicate that C. monoculus is a multiple spawner with an estimated batch fecundity of 3100. Condition factor showed an inverse relationship in relation to gonad size during maturation in both sexes and spent fish were in poor condition. In mature males, lipid stores in the post-occipital cephalic protuberance, a secondary sexual characteristic developed during the reproductive phase, which depleted in spent individuals. The success of this fish is attributed to its reproductive capacity and to the phenotypic plasticity that allows it to adapt to the harsh ecological conditions that prevail in the semi-arid region of Northeast Brazil.

Reproduction of Cichla kelberi Kullander and Ferreira, 2006 introduced into an artificial lake in southeastern Brazil

“…The length distributions were different for the males and females, with the former reaching greater lengths than the latter. The same has been reported for other species of Cichla (Fontenele, 1950;Lowe-McConnell, 1969;Taphorn and Duque, 1996;Câmara et al, 2002;Chellappa et al, 2003;Gomiero and Braga, 2003a;2003b;Muñoz et al, 2006). On the other hand, no differences in length were found between the sexes for Cichla temensis (Humboldt, 1821), Cichla orinocensis (Humboldt, 1821) and Cichla intermedia (Machado-Allison, 1971) in Venezuela (Jepsen et al, 1999).…”

“…The oocytes matured at a size of 428.4 µm, reaching their maximum at 2,203.2 µm. were introduced (Câmara et al, 2002;Chellappa et al, 2003;Espinola, 2005) or different in natural environments (Jepsen et al, 1997;Muñoz et al, 2006). Mortality can be unequal between the sexes (Vazzoler, 1996), causing a difference in the proportion between males and females.…”

Population structure and reproductive period of two introduced fish species in a Brazilian semiarid region reservoir

“…The decrease in the abundance of these species over the course of the study seems to be related to the trophic depression period of the ecosystem. Our results are also in agreement with other studies of introduced species that established successfully in many reservoirs in Brazil (Santos, Rocha, & Frédou, 2010;Chellappa et al, 2003;Santos, Silva, & Viana, 2003;Novaes et al, 2004; Bennemann, Carpa, Galvez, & Shibatta, 2006;Gomes, Dias, & Branco, 2008;Stefani & Rocha, 2009) and other countries (Japsen et al, 1997;Muñoz et al, 2006). Introduced species are extremely difficult to eradicate (Britton & Orsi, 2012), but a proposal to manage and control them is necessary to minimize their potentially harmful effects on the local aquatic community.…”

“…For C. monoculus the statistical analysis showed that the species did not reproduce throughout the year, but showed a long reproductive period that was not markedly seasonal. Similar results for the species were found in other studies (Gomeira & Braga, 2004;Chellappa et al, 2003;Muñoz, Damme, & Duponchelle, 2006;Souza et al, 2008;Gomiero et al, 2009;Normando et al, 2009;Vieira, Salvador, Melo, Santos, & Bazzoli, 2009).…”

“…The differences in size at first maturation can be attributed to several factors, such as species differences, methods of determining the size at first maturation, or adaptation to the environment (Helfman et al, 2007). Most previous works, Carnelós and Benedito-Cecilio (2002), Chellappa et al (2003) and Gomiero and Braga (2004), used the method described by Vazzoler (1996), where the fit is manual. Souza et al (2008) considered the size at first maturation to be the shortest length at which individuals at the advanced maturation stage were found.…”