<b>Influence of environmental integrity on the reproductive biology of <i>Astyanax altiparanae</i> Garutti & Britski, 2000 in the Ivinhema river basin

Abstract

In this study, it was examined the reproductive biology of Astyanax. altiparanae, in streams with different levels of environmental disturbance in the Ivinhema river basin (Mato Grosso do Sul State, Brazil). Samplings were conducted between July 2001 and November 2011, at 101 sites, using sieves, seining nets, gill nets and electrofishing. Streams were classified into three levels of environmental integrity. We analyzed 735 specimens, 410 females and 325 males. Females predominated in impacted streams and both sexes presented nearly the same pattern of length distribution in the three levels of environmental integrity. Females reached gonadal maturity with greater lengths (L 50 = 55.67mm) in altered and impacted streams and had higher reproductive activity between October and December. The species showed higher Condition Factor and higher reproductive intensity in the impacted streams. Our results evidenced that in impacted sites the species exhibited a good ability to allocate a significant portion of its energy to reproduction, probably due to the greater supply of food.

Spatiotemporal variation in life history traits of three small fishes in streams of south‐eastern Brazil

“…Across all multiple regression models, explained variation was relatively low (less than 17%), which implies that other factors that were not measured in this study, such as resource availability and intra-or interspecific interactions, could potentially be important in explaining variation in these reproductive traits. All three studied species exhibited spatial variation in length at first maturity, and both G. brasilienis and A. altiparanae showed reduced values when compared to other studies (Agostinho et al 1984;Santos & Fontoura 2000;Mazzoni & Iglesias-Rios 2002;Viana et al 2014). Differently, length at first maturity for P. argentea was the same as that found in other studies (Gomiero & Braga 2007).…”

“…conductivity and dissolved oxygen). All three studied species exhibited spatial variation in length at first maturity, and both G. brasilienis and A. altiparanae showed reduced values when compared to other studies (Agostinho et al 1984;Santos & Fontoura 2000;Mazzoni & Iglesias-Rios 2002;Viana et al 2014). However, no study has assessed the effect of environmental factors on reproductive traits, and only two have evaluated the effect of habitat characteristics on P. argentea at the population level (Leal et al 2013;Takahashi et al 2013).…”

Fourier transform-infrared photoacoustic spectroscopy applied in fish scales to access environmental integrity: A case study of Astyanax altiparanae species

“…Therefore, the availability of food depends on the condition of the environment in which the individual is inserted and this variation particularly occurs in species that have higher food plasticities, such as A. altiparanae [3,37]. Ibañez et al [20] stated that the morphology and chemical composition of fish scales can be adjusted by seasonal, location or habitat variability and also by availability and characteristics of food, leading to a differentiation of phenotypic characteristics.…”

“…This evidence can be confirmed by interpreting the 11 peaks selected for statistical analysis, since four of them were most significant: 1234, 1396, 2969 and 3309 cm À1 . Between them, only the 1234 cm À1 (CAN = Amide III) and 2969 cm À1 (CH 3 ) peaks were the most important in explicating the separation of the first canonical root: the peak at 1234 cm À1 was responsible for moving the ellipse for stream #3 to the positive side in the first canonical root; this shift is caused by the feeding habits or the food types that are available in the environment, which is known to have a strong influence on a great number of fish species [36,37]. It can be expected that protein concentration is in excess in stream #3, because the water has a higher electrical conductivity and consequently, a greater accumulation of organic matter.…”

“…Average photoacoustic spectra from inside faces for scales of the A. altiparanae specie, from the streams #1, #2 and #3. [37,40]. A. altiparanae fish species is considered to be omnivorous, i.e., it eats plants and animals in balanced proportions, and this species is also generalist/opportunistic because it can feed on different food items in its diet [41,42].…”