Length-weight and length-length relationships of 10 fish species from headwater streams of the lower Iguassu River basin, Brazil

ABSTRACT

Length-weight (LWR) and length-length (LLR) relationships are widely used in management programs and monitoring of fish stocks. We estimated the LWR and LLR of 10 fish species sampled from nine streams of the lower reach of the Iguassu River Basin, Paraná, Brazil. All LWR fits were significant, with b values ranging from 2.37 to 3.62 and an average value of 3.07. Most species showed isometric growth. Significant differences in the LWR between sexes were observed only for Phalloceros harpagos Lucinda, 2008 in the Três Barras stream. All LLR fits were significant, with b values ranging from 0.98 to 1.25 and an average value of 1.15. Significant differences between sexes for the LLR were observed for Rhamdia voulezi Haseman, 1911 in the Arroio Passo Liso stream. First records of the LWR for four species - Ancistrus mullerae Bifi, Pavanelli & Zawadzki, 2009, Bryconamericus pyahu Azpelicueta, Casciotta & Almirón, 2003, Cambeva stawiarski (Miranda Ribeiro, 1968), and Cambeva taroba (Wosiacki & Garavello, 2004) - and the LLR for six species - A. mullerae, B. pyahu, C. davisi, C. stawiarski, C. taroba, and P. harpagos - and a new record of maximum standard length for two species - C. taroba and B. pyahu - are presented.

KEY WORDS:
Allometry; conservation; endemism; population structure; ichthyofauna; individual growth models