July Telescope Shiners Are Smaller

Just like I thought, the telescope shiners we collected at Hurricane Creek on July 7 are smaller than the previous months' collections. The 29 individuals averaged 44.8 mm standard length, and 1.18 g body mass.. May fish, by comparison, averaged 51.59 mm standard length and 2.09 g body mass. I just calculated standard errors for both standard length measurements, and the standard lengths are significantly different (no overlap of the two means +/- 2 standard errors; a t-test would work as well). The mass/length ratios have changed, too: 0.027 g/mm for July fish, while the June fish were heavier at 0.033 g/mm. We only have preliminary GSI data at the moment but I would say that the breeding season is ending for the species, with survivors smaller on average. It appears that the telescope shiner breeding season peaks in May and June, with a sharp decline in July. I'm not really surprised; certainly it's reassuring that the data clearly seem to support this analysis.