Morphological description of larvae of the Mapará Hypophthalmus edentatus (Spix) (Osteichthyes, Hypophthalmidae) in the Itaipu reservoir (Parana River, Brazil)

Abstract

ABSTRACT. The ontogenetic aspects of larvae of Hypophlhalmus edenlalus (Spix, 1829) from the ichthyoplankton samples collected in the Itaipu reservoir between March 1988 and April 1990 were analysed. Sample were caught by 0.5 mm mesh conic-cylindrical plankton net. Larvae of H. edenlalus were identified and described as SilurifOlms from the morphological and morphometric development series. They have a small to medium-sized head, long body, small eyes, little pigmentation, mandibular barbules and 53 to 56 myomeres. High values obtained with cOITelation coefficient (r > 0.97; P< 0.001) show that growth was proportional in different parts of the body. KEY WORDS. Hypophlhalmusedenlallls, fish larvae, Itaipu reservoir, larval development, Parana RiverThe first studies about development offish eggs and larvae in Brazil were conducted by VO IHERING (1934), who successfully developed the induced oviposition technique (WOYNAROVICH & HOVATH 1980). Although these studies began more than 60 years ago, little is known about freshwater ichthyoplankton, since only 2% of Cypriniformes and Characiformes larvae have been identified (RICHARDS 1985).In the upper River Parana basin, studies on the biology and ecology of fish larvae are scarce. Studies are restricted to preliminary surveys of eggs and larvae of the floodplain and Itaipu reservoir (FuEMlITAIPU BINACIONAL 1990; NAKATANI el af. 1993).The family Hypophthalmidae are commercially explored fish in the Itaipu reservoir. According toAGOSTINHO el af. (1994), the maparajuveniles are restricted to the reservoir, marginal lakes of the floodplain and adjacent sites close to these environments. RINGUELET el af. (1967) characterize adults of Hypophlhalmus edenlalus (Spix, 1829) by a high head at the posterior region, compressed body, eyes in ventro-Iateral position, mental barbules next to the mandibular symphysis, tender and uniformly colored skin in the dorsal part with no blotches, and silvery at

Ontogenetic shifts in digestive tract morphology and diet of fish larvae of the Itaipu Reservoir, Brazil

“…Nevertheless, no study has been carried out for their early life stages. There are only descriptions of the morphological development of the young of some species (Nakatani et al 1997, Nakatani et al 1998, Nakatani et al 2001.…”

State of the art of identification of eggs and larvae of freshwater fish in Brazil

“…Studies with larvae of Brazilian freshwater fish are relatively recent. According to Bialetzki et al (2016), the first studies were performed concomitantly in the Amazon and Paraná basins in the 1980s, resulting in descriptions of the early development of Semaprochilodus insignis (Jardine, 1841) (Araújo- Lima, 1985) and Catathyridium jenynsii (Günther, 1862), Hypophthalmus edentatus (Spix, 1829) and Plagioscion squamosissimus (Heckel, 1840) (Nakatani et al, 1997;1998). However, a major breakthrough in research came in 2001 with the publication of several articles describing ichthyoplankton and especially the publication of the book Ovos e larvas de peixes de água doce: desenvolvimento e manual de identificação (Nakatani et al, 2001), which included the morphological description of eggs, larvae and juveniles of 62 species present in several Brazilian watersheds.…”

Reproductive cycle of the Amazonian planktivorous catfish Hypophthalmus marginatus (Siluriformes, Pimelodidae)

“…A group of planktivorous catfish known as "maparás" (Pimelodidae; Siluriformes) are widely distributed in South America, including in the Amazon basin (Carvalho & Mérona, ) and the Paraná River basin (Nakatani, Baumgartner, & Latini, ). These species are highly exploited by the Amazonian extractive fisheries and are among the most important (Cintra, Flexa, Silva, Araújo, & Silva, ; Gonçalves & Batista, ) and the most abundant species of fish in the Amazon region (Gonçalves & Batista, ).…”