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.

Population genetic structure of North American burbot (Lota lota maculosa) across the Nearctic and at its contact zone with Eurasian burbot (Lota lota lota)

“…Caudal peduncle is an ecologically important trait: a long, low caudal peduncle is a particular adaptation to open water and acceleration, whereas a short, high caudal peduncle is better suited to manoeuvrability (Wootton 1991). Burbot from western Europe have a caudal peduncle more like North American burbot, so the morphological differences and similarities were attributed to similarities of climate (Pivnicka 1970) or perhaps lentic-lotic water adaptations within North America (Fisher et al 1996). However, Van Houdt et al (2003) suggested that within L. l. lota, caudal peduncle instead reflects common refugial history.…”

Changes in Population Indices of a Diminishing Burbot Population in the Kootenai River, Idaho, USA and British Columbia, Canada

“…We used values for stock length (S) and quality length (Q) of 200 mm TL and 380 mm TL, respectively, as calculated by Fisher et al (1996). PSD was further defined in terms of RSD using the preferred (P), memorable (M), and trophy (T) lengths recommended by Gablehouse (1984) and calculated for burbot by Fisher et al (1996), where P = 530 mm, M = 670 mm, and T = 820 mm TL.…”

“…We used values for stock length (S) and quality length (Q) of 200 mm TL and 380 mm TL, respectively, as calculated by Fisher et al (1996). PSD was further defined in terms of RSD using the preferred (P), memorable (M), and trophy (T) lengths recommended by Gablehouse (1984) and calculated for burbot by Fisher et al (1996), where P = 530 mm, M = 670 mm, and T = 820 mm TL. We calculated PSDs and traditional RSDs (Willis et al 1993) for both of the unpublished data sets from 1957-1958 as well as for the data from 1979-1982-2004(Partridge 1983, Paragamian and Laude 2008.…”

“…We calculated relative weight (Wr; Wege and Anderson 1978) of burbot based on burbot standard weight (WS; Fisher et al 1996), where loglows = -4.868 + 2.898 logloTL.…”

Kootenai River Fisheries Investigation : Stock Status of Burbot : Project Progress Report 2008 Annual Report.

“…Biopsies were not performed in an effort to reduce stress; therefore, sex of burbot could not be determined. We calculated relative weight (W r ; Fisher et al 1996) for each burbot captured.…”