Fish Health, Ageing, Growth Performance
Fish health assessment is an essential component of fisheries management, particularly when applied to stocked waters. Introducing fish can be a potentially risky business without the necessary steps being taken to ensure the stocked fish are in good condition and free from category 2 parasites or other serious infections. Furthermore, it presents an opportunity to evaluate the quality of the fish the prospective purchaser intends to buy. Fish health is far more than this though. Understanding the parasite mechanisms and bacteria infections that fish are subjected to enables accurate assessment of fishery management techniques and facilitates rapid identification when issues occur.
We routinely undertake fish health checks for stocking and transporting fish as well after pollution events and as part of fisheries investigations. We investigate causes of mortality in fish, in rivers, canals, lakes and stillwaters. As part of our fish mortality work we regularly undertake further investigations including health assessment via our fully equipped laboratory based in our Leicestershire offices.
Ageing fish is undertaken to determine the age structure of populations following biometric data collection from fisheries surveys.
This is useful for assessing the population structure of a location and determining whether it has been impacted by environmental events or anthropogenic activities.
Biometric data is collected to evaluate and quantify the length frequency of fish populations. This enables comparisons between different populations regarding growth and population size structure.
By looking at the growth of an individual fish over several years it is possible to determine whether it’s individual growth, and those of its conspecifics, are above or below expectations, based upon large datasets. In some cases where data is regularly collected, years of poor growth can be determined by comparing previous years growth assessments. This enables the fishery owner, manager, or regulator to identify causes of poor growth, supporting plans to correct this through fisheries management actions.
BFJ carry out fish ageing and growth performance analysis for riverine and Stillwater fisheries. Where we find anomalies, we use this data to support actions required to address issues facing the specific fishery, incorporating these within our reports and recommendations