An assessment of burbot (Lota lota) weight–length data from North American popuplations

Abstract

Declining burbot (Lota lota) abundance across some portions of North America has prompted a search for additional evaluation tools, including a measure of condition. Weight–length data were compiled for 10 293 burbot from 79 North American populations. These data were used to develop a 75th percentile standard weight (Ws) equation using the regression-line-percentile technique. The proposed equation is log10Ws = −4.868 + 2.898 log10 TL, where Ws is the standard weight in grams, and TL is the maximum total length in millimetres. The equation is valid for burbot ≥ 20 cm and will allow calculation of relative weights (Wr) for this species. Based on the length of the longest burbot in our data set (104.3 cm), we propose minimum standardized length categories of 20, 38, 53, 67, and 82 cm for stock, quality, preferred, memorable, and trophy length, respectively. The standard length categories will allow determination of mean Wr by length group, as well as calculation of stock density indices. Differences in Wr values were present between lentic and lotic burbot populations, suggesting variation in body shape and a need for establishment of different Wr objective ranges.