Keshiyu Nakatani's research while affiliated with Universidade Estadual de Maringá and other places

... Therefore, species with this type of eggs may have nocturnal spawning tactics to maximize offspring survival. This reproductive tactic is common in Neotropical fish and aims to protect the offspring from diurnal predators (Bialetzki et al., 1999;Sanches et al., 2006;Suzuki & Pompeu, 2016 F I G U R E 6 Boxplot of fish egg and larval densities (10 m À3 ) in relation to sampling schedules for (a) surface samples and (b) bottom samples. The horizontal lines represent the medians, and the rectangles represent the first and third quartiles. ...

... Despite its economic potential, to date, there are no studies on the early ontogeny of R. microlepis, except for a brief description of juveniles (>20 cm) conducted by Santos (1980). Considering the spatial co-occurrence and high morphological similarity among larvae of anostomids, such as Leporinus friderici (Bloch, 1794), Schizodon fasciatus Spix & Agassiz, 1829, and Rhytiodus argenteofuscus Kner, 1858, descriptive and comparative studies are crucial for the accurate identification of the early stages of this group in nature Godinho et al., 2003;Nakatani et al., 2001;Ponton & Mérigoux, 2001;Sanches et al., 2001). ...

... Another useful feature in the identification of fish larvae, even if they present intra-and interspecific variation, is the count of total or partial myomeres (Araújo- Lima & Donald, 1988;Cajado et al., 2021;Pereira et al., 2017). Myomeres generally correspond to the number of vertebrae, including those of the Weberian apparatus and urostyle, plus one more unit (Araújo- Lima & Donald, 1988;Borges et al., 2000). ...

... Therefore, fish eggs and larvae can be used to assess the relative health of ecosystems through the diversity and the state of fish resources, as well as the impacts from anthropogenic environmental change to natural landscapes (Song et al., 2019). Furthermore, knowledge on temporal and spatial distribution patterns of fish eggs and larvae is important for identifying the spawning areas and reproductive seasons of fish, which is vital for the conservation and management of resources (Bialetzki et al., 2001). In addition, data on the relationships between egg and larval fish distributions and biotic or abiotic factors are crucial for understanding the environmental requirements for spawning (Gogola et al., 2013) and to explain the mechanisms driving patterns of fish egg and larval assemblages (Nonaka, Matsuura & Suzuki, 2000;Gogola et al., 2010). ...

... Complementarily, the functional swim bladder allows the larvae to move along the water column and have greater mobility and stability (Blaxter, 1986). (Cavicchioli et al., 1997;Machado-Allison, 1987;Nakatani et al., 2001). In addition, the presence of a short adipose-fin base (less than one-third of the dorsal fin), visible in post-flexion, distinguishes P. brachypomus from Metynnis species, which have an elongated adipose base (more than one-third of the base of the dorsal fin dorsal) (Ota, 2015). ...

... The greatest species richness in larvae coincided with the springsummer seasons, thus corroborating with the reproductive period of most species of the Upper Paraná River floodplain (Baumgartner et al., 1997;Bialetzki et al., 2005;Castro et al., 2002;Galuch et al., 2003;Reynalte-Tataje et al., 2012;Vazzoler et al., 1997). These results indicate that during this period, a greater number of species with different reproductive strategies use the macrophytes stands in the reproductive period. ...

... Studying early life stages is key for successful conservation programs, and morphological description is an important tool for distinguishing congeneric or sympatric species (Oliveira et al., 2012). The great morphological similarity amongst congeneric species in early life stages (Snyder, 1981) and the lack of taxonomic keys are obstacles to the identification of material collected in the natural environment (Bialetzki et al., 1998). Ahlstrom & Moser (1976) highlighted the importance of biological collections of ichthyoplankton because they enable the determination of life history characteristics, linking larval history to the adult phase. ...

... On the other hand, Vazzoler (1996) observed a positive correlation between pH and the density of some ichthyoplankton [42]. Some researchers found that the preference of certain ichthyoplankton species for waters which are slightly acidic pH may be an acquired behavior [43]. In short, the impact of pH on reproductive processes is not well understood now, but it has been observed to induce spawning in certain ichthyoplankton. ...

... The Amazon river prawn (Macrobrachium amazonicum) is widespread in South America, from Venezuela to Argentina (Holthuis, 1952;Pettovello, 1996;Bialetzki et al., 1997). This species is an important fishery resource along the Amazon region (Moraes-Riodades and Valenti, 2001), being exploited by local fishermen and experimentally produced since the late 1990s (New, 2005;Moraes-Valenti and Valenti, 2010). ...

... Estas observaciones coinciden con la hechas por David-Ruales et al. (2020) sobre la misma especie. Se pueden usar descripciones detalladas de la distribución de los cromatóforos en el cuerpo para identificar las especies en una etapa temprana de su desarrollo (Bettinelli et al., 2012;Meijide y Guerrero, 2000;Nakatani et al., 1997;Santos y Godinho, 2002 La aleta primordial es posiblemente una adaptación para la locomoción en aguas suaves y menos turbulentas y también puede funcionar en la respiración al aumentar la relación de la superficie de la larva (Bettinelli et al., 2012;Geerinckx et al., 2008;Snik et al., 1997). Esta aleta empieza a desarrollarse a partir de la fase de larva vitelina a las 14 HPF (inicia el nado vertical) y se reabsorbe con el tiempo hasta las 228 HPF. ...