Age validation and contrasted growth performances of Pseudoplatystoma punctifer (Siluriformes: Pimelodidae) in two river systems of the Western Amazon

Abstract

The doncella Pseudoplatystoma punctifer is an economically and ecologically important catfish in the Amazon basin. However, little is known about its age, growth and population dynamics parameters. This study aims to validate the formation of growth marks in vertebrae of individuals collected from two rivers systems of the Peruvian Amazon (Amazon-Marañón-Ucayali and Putumayo) and compare growth parameters using the von Bertalanffy growth function between sexes and systems. A total of 372 individuals from the Amazon-Marañón-Ucayali (AMU) system and 93 from the Putumayo River were analyzed. The formation of one growth ring per year was validated and the individual ages ranged from zero to nine years old. Females grew significantly larger than males in both systems. Both females and males grew significantly better in the AMU system than in the Putumayo River. Maximum observed length and size at maturity in the AMU system were lower than those reported in previous studies in the area, and together with an important proportion of juveniles in the catches, suggest that the species is heavily exploited. Further studies on the reproductive biology and population dynamics of the doncella are needed in order to implement management measures more in line with the current situation.

A Synthesis of the Ecology and Conservation of Pseudoplatystoma Catfishes in the Neotropics

“…As noted above, these catfishes are large-bodied compared to other Neotropical species and can grow up to about 130 cm in total length and 100 kg in weight, depending on the species [56]. They can grow to 40 cm in their first year of life [14]. Females grow larger and faster than males.…”

“…Most studies on the growth of Pseudoplatystoma found a similar pattern of growth rings in calcified structures such as otoliths and vertebrae, with opaque ring formation in the hard parts of Pseudoplatystoma, indicating fast growth occurring during the dry season [14,31,50,58,60]. Several studies showed that one opaque ring is formed annually during the dry season and the beginning of the rainy season for P. punctifer, P. tigrinum, and P. mataense in the Peruvian Amazon, Orinoco, and Mamore basins [14,31,57], probably because the dry season is when prey capture is more difficult due to competition with larger catfishes and dolphins and the beginning of the reproductive stage [14,31,33]. However, studies on central and eastern Amazon tributaries are necessary to determine whether the pattern of one ring per annual cycle is consistent for P. fasciatum and P. tigrinum.…”

“…Other fish species-such as gilded catfish Brachyplatystoma rousseauxii (Castelnau, 1855) [58], mapara catfish Hypophthalmus marginatus (Valenciennes, 1840) [57], piaracatinga catfish Calophysus macropterus (Lichtenstein, 1819) [61], and pirarucu Arapaima spp. [59] in the central Amazon-form two growth rings per flood cycle [14]. Validation of ring formation has been done for P. punctifer, P. tigrinum, and P. fasciatum, but it is lacking for P. corruscans, P. reticulatum, and P. magdaleniatum [14,31] Generally, species that are distributed in tropical and temperate regions have faster growth rates in the warmer tropical waters because food availability is the main constraint for growth in tropical regions, while temperature constrains the growth in temperate regions [62,63].…”

“…[59] in the central Amazon-form two growth rings per flood cycle [14]. Validation of ring formation has been done for P. punctifer, P. tigrinum, and P. fasciatum, but it is lacking for P. corruscans, P. reticulatum, and P. magdaleniatum [14,31] Generally, species that are distributed in tropical and temperate regions have faster growth rates in the warmer tropical waters because food availability is the main constraint for growth in tropical regions, while temperature constrains the growth in temperate regions [62,63]. For example, all species of the genus Pseudoplatystoma that are distributed in the tropical areas of the Amazon, Orinoco, and Magdalena basins grow faster than the Pseudoplatystoma catfishes distributed in the Paraná basin (references in Table 2).…”

“…About one-third of all freshwater species occur in the Neotropics, with an estimated Fishes of the genus Pseudoplatystoma support important commercial and artisanal fisheries, and some species have become important to regional aquaculture [11]. Most species of the genus are under pressure from dam construction and overfishing [12][13][14][15][16][17][18]. Two species are of conservation concern: P. corruscans is classified as Critically Endangered [13] and P. magdaleniatum as Endangered by IUCN [19].…”