Biology of Hippocampus patagonicus (Syngnathidae) in Brazilian waters. A species threatened with extinction, with suggestions for the conservation of seahorses in Brazil

• Published in: Latin american journal of aquatic research Vol. 48; no. 1; pp. 47 - 57
• Main Authors: Silveira, Rosana Beatriz, Silva, Jose Clebson da, Benicio, Lua, Silva, Jose Rodrigo Santos
• Format: Journal Article
• Language: English; Spanish
• Published: Pontificia Universidad Catolica de Valparaiso, Escuela de Ciencias del Mar 01-03-2020; Pontificia Universidad Católica de Valparaíso. Facultad de Recursos Naturales. Escuela de Ciencias del Mar
• Subjects: FISHERIES; MARINE & FRESHWATER BIOLOGY; OCEANOGRAPHY; Brasil; fishing resources; bycatch; Hippocampus patagonicus; seahorse; threatened species; reproduction
• ISSN: 0718-560X; 0718-560X
• DOI: 10.3856/vol48-issue1-fulltext-2307

Specimens of Hippocampus patagonicus obtained in the bycatch of trawling in the states of Rio Grande do Sul (RS) and Rio de Janeiro (RJ) were collected in 2012 (n = 199) and 2014 (n = 157), respectively. Mean height of females of reproductive age in RS was 8.89 [+ or -] 1.9 cm, with the fecundity of 366 [+ or -] 195.8 eggs per clutch, and for males of reproductive age, height was 8.79 [+ or -] 1.86 cm and weight 2.3 [+ or -] 1.67 g, with 404 [+ or -] 99 embryos at each gestation. In RJ, height was 9.69 [+ or -] 1.05 cm and weight 2.9 [+ or -] 0.9 g, with the fecundity of 277 [+ or -] 95.06 eggs per clutch, and for males, height was 10.06 [+ or -] 1.02 cm and weight 3.68 [+ or -] 1.18 g, with the fecundity of 156.38 [+ or -] 66 embryos at each gestation. The equations obtained from the weight (W) to height (H) ratio were: W = 0.002 [H.sup.3.182], [R.sup.2] = 0.947 (RS males); W = 0.004 [H.sup.2.914], [R.sup.2] = 0.949 (RS females); W = 0.0050 [H.sup.2.838], [R.sup.2] = 0.793 (RJ males); W = 0.014 [H.sup.2.355], [R.sup.2] = 0.733 (RJ females). RS females produced more eggs (P = 0.023), and males incubated more embryos (P = 0.000) than those of RJ. The mean height of brood pouch formation in males was 4.69 [+ or -] 0.48 cm, 95% CI [4.53; 4.86], while the mean height at first sexual maturity was 8.34 cm (95% CI [7.481; 9.046]). Alternative strategies need to be developed for the conservation of H. patagonicus in Brazil.