Conventional Fisheries Surveys
Traditionally fish surveys comprise of netting or electrofishing methodologies in order to estimate the fish population or determine the assemblage.
The netting surveys are usually seine, fyke, wrap round, box or block net surveys. Trawling is also undertaken where suitable. We deploy Otter and Beam trawls in tidal and estuarine locations. Trapping can provide useful information and is important in controlling invasive species as well as for passive fish removal. We are able to provide fish stock assessment, population estimates, size and length frequency data as well as fish health assessment. We provide services to all aspects of fishery management, providing a ‘solution’ based approach.
Electrofishing is carried out as multiple pass or multi-shock depletion surveys, also referred to as catch depletion surveys.
Continuous qualitative surveys and Point Abundance Surveys by Electrofishing (PASE) are regularly deployed. We carry out numerous electrofishing surveys every year. These can be wadeable, single pass stream surveys, using backpack electrofishing equipment, or larger 4 man electrofishing teams.
BFJ deploy the above methods in order to address our client’s needs and evaluate and quantify fish populations. We have >90 years combined experience in the deployment of conventional survey techniques and are capable of fielding experienced 2-4 man teams throughout the UK. We routinely provide support for Civil engineering companies, which require removal or rescue of fish from target areas, to clearing fish from a section of waterway to enable bridge inspections to be undertaken without damaging the fish and their environment. We are contracted by utility companies to investigate potential pollution effects, and contracted to design and carry out mitigation measures where appropriate.
Novel Fisheries Surveys
Hydroacoustic surveys use sound waves to detect fish within the water column. They are suitable for surveying large lowland tidal rivers and lakes, and are capable of providing estimates, quantifying the total fish population distribution over a single night of surveying. This permits stock assessment for the first time, since conventional methods are often unsuitable for large, dynamic, rivers systems. We employ dedicated acousticians to carry out hydroacoustic surveys and post process the data. Our staff are experienced in operating industry standard equipment. We deploy hydroacoustic surveys across all of the UK.
High Resolution Sonar
We deploy the industry-leading standard: DIDSON-dual frequency identification sonar and ARIS-adaptive resolution imaging sonar equipment. We are experienced in operating both types of sonar for fish surveys and assessment of fish movements around anthropogenic structures.
Both systems are highly capable of monitoring fish movements, and are also used in behavioural studies.