Relative abundance and reproductive tactics of a Loricariidae species at Saraiva Lagoon, Ilha Grande National Park, MS-PR, Brazil

Abstract

Abstract:This study aimed to evaluate population abundance patterns and the main events in the reproductive cycle of Loricariichthys platymetopon at Saraiva Lagoon, Ilha Grande National Park, MS-PR, Brazil. Monthly samplings were conducted from October 2004 to September 2005 in three sections of the lagoon: entrance, middle and end, which resulted in the capture of 175 individuals. Spatial and temporal variation in abundance was obtained through CPUE (number of captured individuals/1000 m 2 of gillnets in 12 hours). The reproductive tactics considered were: duration, time and location of spawning, oocyte diameter and fecundity. The highest relative abundance was recorded in February, in the middle section of the lagoon, and the reproductive period lasted from September to February. The prevalence of females with spent ovaries and at rest in the following months indicated that reproductive activity ceased during autumn and winter. We observed that reproduction was high at the end section of the lagoon. The recorded mean oocyte diameter was 1.67 (SD ± 0.76) mm, mean absolute fecundity was 962.1 (SD ± 382.48) oocytes, and relative fecundity was 7.60 (SD ± 2.25) oocytes/g and 5.13 (SD ± 0.75) oocytes/cm. These tactics, probably are related to the settlement of L. platymetopom in Saraiva A variação espaço-temporal na abundância foi avaliada através da CPUE (nº de indivíduos capturados/1000 m 2 rede em 12 h de exposição). As táticas reprodutivas avaliadas foram duração, época e local de desova, diâmetro de ovócitos e fecundidade. A maior abundância relativa foi registrada em fevereiro, na região média da lagoa e o período reprodutivo estendeu-se de setembro a fevereiro. A prevalência de fêmeas com ovários esgotados e em repouso nos meses subseqüentes indicou que a atividade reprodutiva cessou no outono e inverno. Observou-se que a reprodução foi acentuada na região final da lagoa. O diâmetro médio de ovócitos registrado foi 1,67 (SD ± 0,76) mm, a fecundidade absoluta média 962,1 (SD ± 382,48) ovócitos e a fecundidade relativa 7,60 (SD ± 2,25) ovócitos/g e 5,13 (SD ± 0,75) ovócitos/cm. Essas táticas muito provavelmente, devem estar relacionadas à ocupação da lagoa Saraiva por L. platymetopom, bem como de outros biótopos da planície de inundação do alto rio Paraná. Palavras-chave: peixes, distribuição, diâmetro de ovócitos, fecundidade, período reprodutivo.

Population structure and reproductive biology of Loricariichthys melanocheilus Reis & Pereira, 2000 (Siluriformes: Loricariidae) in the rio Ibicuí, Brazil

“…The values for GSI also began to rise in August/September, peaking in October/November for females and August/September for males. Similar results were found in other Loricariidae in various regions of Brazil, for example, Rhinelepis aspera (Agostinho et al, 1990), Hypostomus commersonii (Agostinho et al, 1991), H. ancistroides (Viana et al, 2008), Rineloricaria latirostris (Barbieri, 1994), Loricariichthys platymetopon (Bailly et al, 2011;Marcucci et al, 2005), L. spixii (Duarte et al, 2007), among others. Males showed distinctly greater condition factor than that of females throughout the study period, probably because of higher energy expenditure of females during the maturation process (Cantanhêde et al, 2007), a feature also reported by Agostinho et al (1990) for Rhinelepis aspera in the rio Paranapanema (state of Paraná).…”

“…In other studies with species of the genus Loricariichthys, e.g. L. platymetopon in the Paranapanema and the Paraná rivers (Marcucci et al, 2005;Bailly et al, 2011) and L. spixii in the Lajes reservoir (Duarte et al, 2007) this pattern also were observed. Although registered for some species, the 1:1 ratio is seldom found.…”

“…Studies conducted on the genus Loricariichthys have focused primarily on L. anus (Valenciennes, 1835), L. platymetopon Isbrücker & Nijssen, 1979(Tos et al, 1997Querol et al, 2002;Marcucci et al, 2005;Bailly et al, 2011) and L. spixii (Steindachner 1881) (Duarte & Araújo, 2001). So far, there is no record in the literature of studies addressing aspects of the biology of Loricariichthys melanocheilus, probably because it is a recently described species and is not widely distributed along several Brazilian basins, but rather, restricted only to the southern region of Brazil.…”

Ecological and phylogenetic determinants of life‐history patterns among ten loricariid species

“…This strong reproductive seasonality is consistent with other studies of loricariids (Dei Tos et al ., ; Querol et al ., ; Marcucci et al ., ; Bailly et al ., ; Zardo & Behr, ) and is coherent with the wide seasonal variation in day length and temperature in this subtropical system. Given the large differences in environmental conditions and resource availability between cold and warm periods, when flood pulses generally occur (Bailly et al ., ; Lowe‐McConnell, ; Scarabotti et al ., , ; Wootton, ), strong selective pressures are expected to concentrate reproduction during the warm season. The reproductive activity of P. vetula during the cold period is consistent with its thermal preferences since this species exhibits particular high abundance throughout the La Plata River, where the lowest average temperatures of the basin are recorded (García et al ., ).…”

“…In the Paraná River, loricariids dominate fish biomass (Scarabotti et al, 2017) and are exploited as a fishery resource (Suzuki et al, 2000). They fulfil a fundamental ecological role in nutrient spiralling (Hahn et al, 2004) as well as linking the base of the food web with top predators (Bailly et al, 2011).…”