Habitat preferences of the burbot (Lota lota) from the River Elbe: an experimental approach

Abstract

An experimental approach was used to analyze preferences of the burbot (Lota lota) with regard to water depth, substrate type and flow velocity. In total, 30 burbots used in the experiments were caught in the middle reaches of the River Elbe by electro-fishing. Immediately after capture, they were placed in a 180 L transportation box with aerated freshwater and taken to the research aquarium of the Zoological Museum Hamburg where they were divided into two groups according to total length: group I, 10.0-16.5 cm; group II, 20.0-30.0 cm. Prior to the experiments the fish were adapted to laboratory conditions for four weeks at 20°C in four tanks, each containing 720 L water. For each experiment, three L. lota were transferred to an additional 1350 L experimental tank. After a one-day adaptation phase each experiment ran for three continuous day and night phases. Burbot preferences were tested for (i) water depth, (ii) substrate size, (iii) water depth and substrate size combined, and (iv) water depth, substrate and flow velocity in combination. Diurnal and nocturnal activities were recorded and analyzed throughout all experiments. Burbots of both length groups showed a significant preference for deeper water depths and large cobble substrate. Substrate type was found to be the dominant factor determining habitat preferences of L. lota when investigated in combination with water depth. In experiments combined with flow velocity, substrate and water depth were the most important factors determining burbot habitat preferences, and flow velocity of minor importance. In general, burbots were most active at night, while daytime activity was much lower. However, in all experimental approaches in the smaller length group the burbots displayed much higher day-and night-time activity than did the individuals in the larger length group. U.S.

Habitat use of non-native burbot in a western river

“…Thus, burbot likely select habitats with relatively low mean current velocity because of their poor swimming endurance. Depth is commonly cited as a highly influential variable for predicting the presence of burbot (Dillen et al, 2008;Dixon & Vokoun, 2009;Eick, 2013). However, none of our top models reflected the influence of depth on either burbot occurrence or relative abundance.…”

“…However, none of our top models reflected the influence of depth on either burbot occurrence or relative abundance. In laboratory experiments, Eick (2013) reported that burbot selected habitats with greater depth. However, the maximum depth used in Eick's experiments was 90 cm making inference to natural systems tenuous.…”

Sampling techniques for burbot in a western non‐wadeable river

“…Mean depth, current velocity, substrate composition and bank type were hypothesised to be the primary factors affecting the probability of detecting burbot (Dixon & Vokoun ; Eick ; Table ). Flaming Gorge and Fontenelle reservoirs were hypothesised to act as thermal refugia for burbot during periods of high mean water temperature and as a ‘source’ of burbot.…”

“…Additionally, site-and sample-specific covariates were added to occupancy models to explain variability in detection by season and gear for juvenile and adult burbot. Mean depth, current velocity, substrate composition and bank type were hypothesised to be the primary factors affecting the probability of detecting burbot (Dixon & Vokoun 2009;Eick 2013; Table 1). Flaming Gorge and Fontenelle reservoirs were hypothesised to act as thermal refugia for burbot during periods of high mean water temperature and as a 'source' of burbot.…”

Survival, Movement, and Distribution of Juvenile Burbot in a Tributary of the Kootenai River

“…Highquality locations were those dominated by deep pools and large substrate (i.e., depth > 1.5 m; substrate > 64 mm) within 1 km of the release location. Deep habitats with large substrate are commonly reported as important habitat characteristics for Burbot (Dixon and Vokoun 2009;Eick 2013;Klein et al 2015). Moderate-quality habitat locations lacked deep habitats with large substrate within 1 km of the release site.…”