Abundance, sex-ratio, length–weight relation, and condition factor of non-annual killifish Atlantirivulus riograndensis (Actinopterygii: Cyprinodontiformes: Rivulidae) in Lagoa do Peixe National Park, a Ramsar Site of Southern Brazil

Background. The genus Atlantirivulus includes 11 species distributed along coastal river basins and lagoons of eastern and southern Brazil. Most killifishes are threatened with extinction mostly due to their restricted distribution ranges, small population sizes and habitat loss; poor knowledge on ecological and life history information further increase the threats. Atlantirivulus riograndensis (Costa et Lanés, 2009) is a non-annual, small-sized fish endemic in the Laguna dos Patos basin and adjacent coastal areas in southern Brazil. There is no information on the life history and ecology of the species. In this paper, we analyzed population traits of A. riograndensis to support conservation efforts. Materials and methods. Fishes were captured with a D-shaped hand net in six sampling surveys carried out between 2008 (June, August, October) and 2009 (March, August, October) in the type locality of A. riograndensis. The variation of abundance, body size, and condition factor over time, sex ratio and length–weight relations were analyzed. Results. The estimated abundance was of 1.97 specimens per 1 m2. The TL means increased along the year, and males were larger than females. Strong differences in proportions of sexes were detected, with high bias for females. The species showed allometric positive growth (b=3.3), and the general condition factor (CF) was 0.258 ± 0.003. Conclusion. Atlantirivulus riograndensis inhabits small water bodies and apparently has a small population size. The population is female-biased, and males are typically bigger than females. The species has an allometric positive growth. The body size variation is related to individual growth throughout each study year, and probably by high mortality of adults in dry season. This study presents new original data on basic traits of the natural history of A. riograndensis. The observed results may be used to assist the development of management strategies and conservation of the species and its habitat, mainly in a region where 90% of wetland systems were lost by agriculture, and the remaining areas are at high risk due to the expansion of exotic pine plantations

Austrolebias quirogai (Actinopterygii: Cyprinodontiformes: Rivulidae) in Brazil: occurrence, population parameters, habitat characteristics, and conservation status

Background. The Neotropical genus Austrolebias is the most diverse of the Rivulidae family, with 22 species recorded in Brazil, with 21 found in the state of Rio Grande do Sul. Austrolebias quirogai Loureiro, Duarte et Zarucki, 2011 is an annual fish previously only found in Uruguay and there is currently no information about their ecology and life history. Here, we recorded A. quirogai for the first time in temporary wetlands in Brazil. Furthermore, we provide information about population parameters, life history traits, conservation status, and habitat characteristics. Materials and methods. We captured the fish with a D-shaped hand net in a sampling survey carried out in October 2012 in the Jaguarão-Chico River, Aceguá municipality, Brazil. We analysed density (CPUA), body size, length–weight relation (LWR), condition factor (K), and sex ratio. Results. We recorded a total of three populations of Austrolebias quirogai in the Jaguarão-Chico River. The CPUA was 0.33 fish · m–2. The sex ratio relation did not differ significantly and was 1.5 : 1 (M : F). The mean body size between sexes was not statistically different. The LWR of A. quirogai was W = 0.011TL3.23. The value of parameter b was significantly different from 3.0 for males and females, both sexes presenting positive allometric growth. The K for A. quirogai differed between sexes. Females had higher values than males. All populations of A. quirogai were found in ponds smaller than 1000 m² and were degraded by the activity of rice and soybean cultivation and overgrazing. We consider A. quirogai an endangered species in Brazil because of: its reduced area of occupancy, populations becoming severely fragmented, and suffering a continuous decrease in their area of occupancy and the quality of habitat. Conclusion. The observed results may be used to assist the development of management strategies and conservation of the species and its habitat. Moreover, they provide basic information for the evaluation of the conservation status of the species according to IUCN criteria and for the definition of priority areas for conservation in southern Brazil. Further studies should focus on the distribution, life history and ecology of the species to aid in their conservation

Austrolebias quirogai (Actinopterygii: Cyprinodontiformes: Rivulidae) in Brazil: occurrence, population parameters, habitat characteristics, and conservation status

Background. The Neotropical genus Austrolebias is the most diverse of the Rivulidae family, with 22 species recorded in Brazil, with 21 found in the state of Rio Grande do Sul. Austrolebias quirogai Loureiro, Duarte et Zarucki, 2011 is an annual fish previously only found in Uruguay and there is currently no information about their ecology and life history. Here, we recorded A. quirogai for the first time in temporary wetlands in Brazil. Furthermore, we provide information about population parameters, life history traits, conservation status, and habitat characteristics. Materials and methods. We captured the fish with a D-shaped hand net in a sampling survey carried out in October 2012 in the Jaguarão-Chico River, Aceguá municipality, Brazil. We analysed density (CPUA), body size, length–weight relation (LWR), condition factor (K), and sex ratio. Results. We recorded a total of three populations of Austrolebias quirogai in the Jaguarão-Chico River. The CPUA was 0.33 fish · m–2. The sex ratio relation did not differ significantly and was 1.5 : 1 (M : F). The mean body size between sexes was not statistically different. The LWR of A. quirogai was W = 0.011TL3.23. The value of parameter b was significantly different from 3.0 for males and females, both sexes presenting positive allometric growth. The K for A. quirogai differed between sexes. Females had higher values than males. All populations of A. quirogai were found in ponds smaller than 1000 m² and were degraded by the activity of rice and soybean cultivation and overgrazing. We consider A. quirogai an endangered species in Brazil because of: its reduced area of occupancy, populations becoming severely fragmented, and suffering a continuous decrease in their area of occupancy and the quality of habitat. Conclusion. The observed results may be used to assist the development of management strategies and conservation of the species and its habitat. Moreover, they provide basic information for the evaluation of the conservation status of the species according to IUCN criteria and for the definition of priority areas for conservation in southern Brazil. Further studies should focus on the distribution, life history and ecology of the species to aid in their conservation

Killifish eggs can disperse via gut passage through waterfowl

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