Reproductive biology of the armored catfish Neoplecostomus microps in a coastal Atlantic Forest stream, southeastern Brazil

This work aims to analyze reproductive attributes of the species Neoplecostomus microps (Steindachner, 1877), a well-known species of the catfish family Loricariidae but little contemplated in ecological studies. We describe the reproductive behavior of the species and compare the patterns identified in 2 different basins. The specimens (117 males and 102 females), collected in the Macaé River, did not present a bias in sex ratio during the year. In the largest length classes, males predominated and attained earlier maturity than females. The length-weight relationship showed positive allometric growth for both sexes. The variation of the gonadosomatic index and frequency of maturation stages indicated a reproductive period of 4 to 6 mo, starting in September and reaching a peak in November. The mean absolute fecundity was 43.83 (SD = 7.62) oocytes, ranging from 32 to 55 oocytes. The frequency distribution of oocyte diameter of mature ovaries revealed 3 clutches, suggesting batch spawning. A prolonged reproductive period, low fecundity, large eggs, possible parental care, and repeated spawns recorded for N. microps suggest a strategy that maximizes parental fitness. The population structure and reproductive characteristics of this species indicate a tendency toward equilibrium. The early maturation in females in the Macaé River population may favor a more rapid replacement of juveniles in the population as a response to the unstable environmental conditions that the population experiences in the rainy season

Reproductive biology of the Neotropical catfish Iheringichthys labrosus (Siluriformes: Pimelodidae), with anatomical and morphometric analysis of gonadal tissues

The reproduction of Iheringichthys labrosus (Lütken, 1874) from the Turvo River, Brazil, was studied using anatomical, biometric, histological, and ultrastructural techniques. Between April 2014 and March 2015, a total of 278 males and 512 females were captured bimonthly. The testes of Iheringichthys labrosus are fringed and possess a cranial spermatogenic region and an exclusively secretory caudal region. Histologically, the cranial region is composed of seminiferous tubules with spermatogenesis being completed in cysts. The spermatozoa are of the primitive type with a spherical head and have a rudimentary intermediate piece and a long tail with an axonemic arrangement of 9 + 2. The caudal region does not form an individualized gland, and cells in this testis area have characteristics of protein secretion. A variable density electron-dense secretion accumulates in the cisternae of the rough endoplasmic reticulum in the lumen of the seminiferous tubules and in the testicular ducts during maturation. The cortical alveoli are discontinuous, and the zona pellucida consists of three layers crossed by pore canals, and the follicular cells are squamous in the early stages of oogenesis and cuboidal in advanced stages. The gonadosomatic index was associated with the maturation of the gonads while the condition factor indicated that the fish feed less and utilize adipose reserves during the reproductive period. Males and females reproductively functional throughout the year with spawning being partial or multiple, similar to that reported in studies of the species in lentic environments