Bringing back the burbot via hydrological rewilding

The burbot (Lota lota) is a freshwater fish, accepted to have gone extinct from the UK in the 1970s, that requires good water quality and a mixture of slow flowing, deep water, backchannel, and floodplain habitat. These requirements, if incorporated into conservation objectives or habitat management plans, have the potential to drive reach-scale restoration for the benefit of local aquatic biodiversity and ecosystem services by creating more heterogeneous habitat with improved longitudinal and lateral habitat connectivity.

This study will assess whether there is suitable river habitat that could support a reintroduced burbot population. The site chosen for evaluation is the River Wissey, Norfolk, UK, as it is within the burbot's historical range. Specimens dating from the 1930s have been traced to the Wissey, and the river has been subject to preliminary investigations such as a population viability analysis (Worthington et al., 2011a). The project seeks to establish baseline ecological, hydrological, and hydro-chemical data, which could be used to design a successful reintroduction scheme. The Wissey's hydrology will be studied using low-cost, opensource water level sensors to collect primary data to build a hydraulic model to understand temporal and spatial variations in floodplain inundation, key to burbot spawning. A local monitoring network for temperature will be established to study temporal and spatial variations in thermal regime, to validate the habitat's suitability alongside historical data. Walkover surveys will be used to map meso- and micro river habitats within the study area. The results will provide a comprehensive study of the potential reintroduction site, key for the success of a species reintroduction and to help prioritise future restoration activities.