Use and effect of freeze branding on roach (Rutilus rutilus L.)

Abstract

We tested the effects of freeze branding on growth, survival and mark retention in roach Rutilus rutilus L. (82-268 mm in total length). Markings were applied at two positions on the skin: (1) the depressed area above the anal fin, (2) the muscles above the lateral line and between the caudal and dorsal fins. A control group received no mark. The experiment duration was 30 days, and 120 roach were selected and distributed into three lots. Retention rates were high and ranged between 94% for position 2 and 100% for position 1. Survival rate after 1 month was 87% for freeze branded roach at position 2, 90% for position 1 and 92% for unmarked fish. These differences were not statistically significant. A significant decrease of linear growth was observed for individuals marked at position 2 (3.2 mm.month-1), but the implication of the brand itself was unclear. We discuss the short- and long-term properties of freeze branding techniques on roach.