Quantitative and qualitative variables of semen from surubim do Iguacu, Steindachneridion melanodermatum Garavello, 2005 /Variaveis quantitativas e qualitativas de semen de Surubim do Iguacu Steindachneridion melanodermatum Garavello, 2005

The objective of the present work was to assess the qualitative and quantitative characteristics of semen from the surubim do Iguacu (Steindachneridion melanodermatum). Induced spermiation was achieved in eleven males with mean weight of 1.76 [+ or -] 0.48 kg and average age of two years and semen was collected by stripping. The average volume was 1.34 [+ or -] 0.73 mL. The duration of sperm motility was 154.4 [+ or -] 72.6 and 149.0 [+ or -] 77.5 seconds after activation with hatchery water and distilled water, respectively. The sperm concentration estimated by hemocytometer was 5.423 [+ or -] 2.155 x 1010 spermatozoa/mL. The results indicate that S. melanodermatum semen is easily obtained during the spawning season and the seminal characteristics are adequate insemination and subsequent in vitro fertilization. Keywords: catfish, fish, Iguacu river, reproduction, sperm quality, spermatozoa, Siluridae. O objetivo do presente trabalho foi avaliar caracteristicas qualitativas e quantitativas do semen de surubim do Iguacu (Steindachneridion melanodermatum). Para as analises, utilizaram-se onze machos com peso medio de 1,76 [+ or -] 0,48 kg e idade media de dois anos, submetidos ao tratamento de hipofisacao. O volume medio de semen coletado foi de 1,34 [+ or -] 0,73 mL. O tempo medio de motilidade dos espermatozoides apos a coleta foi de 154,4 [+ or -] 72,6 e 149,0 [+ or -] 77,5 segundos para ativacao com agua do tanque e agua destilada, respectivamente. Para a concentracao espermatica, a media foi de 5,423 [+ or -] 2,155 x [10.sup.10] espermatozoides/mL. Os resultados indicam que o semen de S. melanodermatum e facilmente obtido no periodo reprodutivo analisado, e que as caracteristicas seminais avaliadas sao adequadas para reproducao induzida. Palavras-chave: bagre, peixe, rio Iguacu, reproducao, qualidade espermatica, espermatozoides, Siluridae.