Article
| Article name | LIFE HISTORY, THREATS, AND CONSERVATION OF THE BRAZILIAN ANNUAL FISH OPHTHALMOLEBIAS CONSTANCIAE IN TEMPORARY WETLANDS |
| Authors | Gustavo H.S. Guedes, PhD Student, Department of Animal Biology, Federal Rural University of Rio de Janeiro (23894000, Brazil, Seropédica, BR-465); iD ORCID: https://orcid.org/0000-0001-8155-8337; e-mail: gustavohsg@outlook.com |
| Reference to article | Guedes G.H.S., Silva A.C.S., Araújo F.G. 2026. Life history, threats, and conservation of the Brazilian annual fish Ophthalmolebias constanciae in temporary wetlands. Nature Conservation Research 11(4): 53–64. https://dx.doi.org/10.24189/ncr.2026.029 Electronic Supplement 1. Additional information for the paper by Guedes et al. (2026) (Link) |
| Section | Research articles |
| DOI | https://dx.doi.org/10.24189/ncr.2026.029 |
| Abstract | Ophthalmolebias constanciae (Cyprinodontiformes: Rivulidae) is a Critically Endangered (CR) annual fish, endemic to the coastal plains of the state of Rio de Janeiro, Brazil. This study was aimed to provide novel data on its life-history traits (body and egg size, fecundity, sex ratio, and length-weight relationship), geographic distribution, habitat characteristics, and to assess emerging threats, including global trade and ex-situ maintenance, as well as changes in land use and land cover over a 22-year period (2003–2025). The species was recorded in only three temporary wetlands, characterised by acidic waters (pH 5.7 ± 0.7) and low dissolved oxygen concentrations (2.6 ± 0.6 mg/L). Total body length ranged from 33–54 mm in males and 30–45 mm in females. Batch fecundity varied from 26–69 oocytes (mean: 44 ± 12 oocytes), with oocyte diameters ranging from 0.80 mm to 1.41 mm (mean: 1.01 ± 0.13 mm). Males were significantly larger than females, and the sex ratio was biased toward females (2.1 females : 1.0 male). The species is illegally traded and maintained ex-situ in at least 13 countries, including regions of North America, Europe, Asia, and Oceania. Land use and cover data revealed increasing anthropogenic pressure on the species' habitats, with a loss of 25% of natural cover between 2003–2025. By combining ecological, biological, and threat data, this study strengthens the basis for evidence-based conservation of Ophthalmolebias constanciae. |
| Keywords | aquarium trade, Atlantic Forest, Brazil, endangered fauna, killifish, reproduction, Rivulidae, temporary ponds |
| Artice information | Received: 29.04.2026. Revised: 19.06.2026. Accepted: 31.07.2026. |
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