Periodic life history strategy ofPsectrogaster rutiloides, Kner 1858, in the Iquitos region, Peruvian Amazon

Abstract

The present study objective was to determine some of the main life history characteristics of the chiochio, Psectrogaster rutiloides, a heavily fished, yet poorly studied species of the Peruvian Amazon. Over an annual cycle between 2006 and 2007 a monthly sampling of P. rutiloides on the Iquitos market provided a total of 2973 individuals. The species reproduces during the rainy season, during the first part of the flooding period. First sexual maturity is reached at about 2 years of age and 95 mm standard length (SL) for both males and females. Batch fecundity was related to fish size and varied from 59 800 to 149 100 oocytes, with oocytes diameters of 1.34 AE 0.11 mm, valid for females of 141 and 152 mm SL and of 102.9 and 149.6 g body mass, respectively. Females grew faster than males in every age class, a difference gradually increasing from 7% at age one to 10% at age nine, which corresponded to the oldest individuals sampled. Estimated mortality parameters and exploitation rates suggested over-exploitation of the species in the Loreto region.

Species‐level ichthyoplankton dynamics for 97 fishes in two major river basins of the Amazon using quantitative metabarcoding

“…Their presence, and in particular that of Brachyplatystoma filamentosum , is surprising. Although these species are highly fecund owing to their large sizes (García Vásquez et al, 2009), other species, particularly among Characiformes, have much higher relative fecundities (per unit body mass; e.g., García Vásquez et al, 2015). Hence, their size‐related fecundity cannot account for the observed larval flows.…”

Conservation of migratory fishes in the Amazon basin

“…Overharvesting, however, is no longer limited to large species and was recently also suggested to affect regionally some of the smaller Characiformes that now make up most of the catches, such as P. nigricans (Bonilla‐Castillo, Agudelo, Gómez, & Duponchelle, 2018; Catarino, Campos, Garcez, & Freitas, 2014) or Psectrogaster spp. (Garcia Vasquez, Vargas, Sánchez, Tello, & Duponchelle, 2016).…”

Population dynamics of Mylossoma albiscopum (Characiformes: Serrasalmidae) in the Ucayali River

“…Mylossoma albiscopum from the Ucayali river basin, according to the seasonality of reproductive cycle, size and age at maturity and total spawning, can be considered as r‐strategic species, as defined by Winemiller (1992). The breeding period of M. albiscopum , which coincides with rising and high‐water periods, is a characteristic pattern of many migratory and commercially important Amazonian fishes (Bonilla‐Castillo et al, 2018; García‐Vásquez et al, 2015; Riofrío‐Quijandría et al, 2017). During this period, floodplains represents as biotopes that are used as refuge and breeding grounds for these species (Azevedo et al, 2021; Zacardi & Ponte, 2021), also generates favourable conditions for the development of plankton and periphyton that serve as food for the early life stages of these species, such as postlarvae and juveniles (Cajado et al, 2020; Campos‐Silva et al, 2021) that favour their development and recruitment (Castello et al, 2019), until they reach sizes that allow them to avoid predators.…”

“…It is a species that, in the Ucayali River basin, presents a small length at first gonadal maturity (14 cm TL) and that, based on information reported in other basins and previous decades (Beltrán‐Hostos et al, 2001), it can be inferred that the high fishing pressure on the species in the Ucayali basin (García‐Vásquez et al, 2015), where the higher fishing intensity affects a reduction of maximum length and length at first gonadal maturity (Correa et al, 2015). Another possibility could be the existence of genetically distinct populations, with phenotypic differences that are a response to environmental conditions, or differential exploitation rates.…”