Variations in reproductive strategy of the silver Arowana, Osteoglossum bicirrhosum Cuvier, 1829 from four sub-basins of the Peruvian Amazon

Abstract

Summary The aim of this study was to assess the variability of reproductive characteristics of the silver Arowana, Osteoglossum bicirrhosum, in four sub‐basins of the Peruvian Amazon: the Amazonas, Ucayali, Napo and Putumayo rivers. An illustrated, detailed gonadal maturation scale is proposed for a clearer determination of the reproductive status of male and female Arowana. The breeding season occurred during the dry season and early rising waters in the Amazonas and Ucayali, whereas it was restricted to the dry season in the Napo and Putumayo. A same female can reproduce more than once during the breeding season. Age at maturity was reached during the second year, at sizes varying between 43–45 cm for males and 46–50 cm SL for females. Important variations in fecundity were observed between fish of the four sub‐basins, whereas mean oocytes diameter and mass did not vary significantly, suggesting differences in reproductive investment. Together with previously reported variations of growth patterns in the same sub‐basins, these results suggest the existence of distinct populations in the Peruvian Amazon, with important consequences for management and conservation, but also for future aquaculture development programs.

Diversity in reproductive traits of arapaima (Arapaima spp., Müller, 1843) in Amazonian várzea floodplains: Conservation implications

“…the genus Cichla ; Gomiero & Braga, ). Even within species, reproductive variation can be observed, resulting from environmental gradients, genetic diversity, and abiotic factors such as variation in habitat or flood pulse patterns (Duponchelle et al, ; McDermid, Shuter, & Lester, ; Vieira et al, ; Zhao, Shuter, & Jackson, ). However, because notable variation is not observed in flood‐pulse or habitat characteristics in the Lower Amazon study area, where there are anthropogenic pressures from cattle ranching and agricultural practices, they are unlikely to be drivers of the 30‐cm difference in size at first maturity for female arapaima in the area.…”

Interspecific Genetic Differences and Historical Demography in South American Arowanas (Osteoglossiformes, Osteoglossidae, Osteoglossum)

“…Two arowana species are currently recognized: the black arowana, Osteoglossum ferreirai and the silver arowana, Osteoglossum bicirrhosum . However, cryptic diversity is potentially present in the genus, as suggested by substantial differences among populations of both species, particularly at reproductive strategies and growth patterns [10,11], and morphometric characteristics [12]. Osteoglossum ferreirai occurs in Negro and Orinoco river basins, living mainly in acidic blackwaters, like in the Negro, Bita, and Tomo rivers [13,14].…”

The Research Network on Amazonian Ichthyofauna

“…Research efforts are being undertaken to better understand the life history strategies of the economically important species, including studies on breeding seasons, age structures and growth of populations, ages at first sexual maturity, as well as measures on fecundity and mortality. Such studies are fundamental to providing a qualitative basis for fisheries management (Duponchelle et al., ; García‐Vásquez et al., ). Nevertheless, there is still a huge gap in knowledge regarding these highly diverse fish populations, with little known of the breeding sites of most of the migratory species (Duponchelle et al., ; García‐Dávila et al., ).…”

“…Such studies are fundamental to providing a qualitative basis for fisheries management (Duponchelle et al., ; García‐Vásquez et al., ). Nevertheless, there is still a huge gap in knowledge regarding these highly diverse fish populations, with little known of the breeding sites of most of the migratory species (Duponchelle et al., ; García‐Dávila et al., ). Such information is essential to define appropriate management strategies.…”

“…Fish exploitation for the ornamental trade is also a subject of concern in the region, since many species are difficult to identify (i.e. the genus Apistogramma ); knowledge thereof is either limited or even lacking (Duponchelle et al., ; Quérouil et al., ). Thus intensified studies on these species are urgently needed to determine the conservation status of these populations.…”