Spatial segregation in the reproductive activity of Neotropical fish species as an indicator of the migratory trait

Abstract

This study focused on the distribution of fish with high reproductive activity along a basin, using a 430 km stretch of the Cuiabá River in Brazil as a model. The main objective of this study was to identify those fish that migrate long distances for reproduction, among all the basin species. Thus, a set of working criteria are proposed to classify species according to their reproductive behaviour (i.e., reproductive activity and distribution). Samplings were performed in the Cuiabá River basin, encompassing several environments (river, channels and lakes) during the reproductive periods (between October and February), from 2000 to 2004. Species occurrence (presence and absenceproxy of distribution) across the basin and index of reproductive activity values were used as criteria to identify the species that perform long-distance longitudinal migrations for reproduction. The study confirmed the classification of long-distance longitudinal migration species; nonetheless, some species were not classified as described in the literature. The proposed sequential criteria have proven to be effective in the classification of long-distance longitudinal migrations species and certainly contribute to filling some existing knowledge gaps of reproductive traits. This classification is of fundamental importance in planning new dam projects, in decision making and in the development of management and conservation actions for the ichthyofauna.

Follicular complex may predict reproductive tactics in siluriform fishes

“…Teleost fish have different reproductive tactics, for example, migration [ [1] , [2] , [3] ], different types of spawning [ [4] , [5] , [6] ], parental care that occurs in different ways such as the storage of fertilized eggs in the mouth [ [7] , [8] , [9] ], the construction of nests and the maintenance of continuous aeration of the eggs [ [10] , [11] , [12] ]. In females, mature oocytes indicate some reproductive tactics such as the reproductive period [ 13 , 14 ] and type of spawning [ 15 , 16 ], and the animal's fecundity can be estimated [ 5 , 17 , 18 ].…”

Spatiotemporal diet shifting in a neotropical fish species: The role of riparian vegetation and seasonal inundation

“…The pacu is a lotic species that can reach lengths of more than 70 cm and reach the first sexual maturation at approximately 35 cm (Costa and Mateus 2009). Although adult individuals can be found throughout the river, spawn are restricted to the upstream reach, at the onset of the rainy season (austral spring, between October and January) after upstream migration (Ferraz de Lima and Chabalin, 1981;Costa and Mateus 2009;Rauber et al, 2021). Pacu is an omnivorous with a tendency to herbivory, and its diet is mainly composed of leaves, fruits, seeds, and flowers, being able to feed occasionally on small invertebrates and fish (Britski et al, 2007;Urbinati et al, 2010;Sado et al, 2020).…”