Habitat loss and fragmentation have caused declines in the abundance and distribution of butterflies, particularly habitat specialists. The Chequered Skipper, Carterocephalus palaemon , has been extinct in England since 1976 after declining from the 1940s predominantly due to changes in woodland management including afforestation and the decline in traditional coppice management. To enable C. palaemon to flourish again, this s...

Flavobacterium psychrophilum is one of the most important pathogens affecting cultured rainbow trout ( Oncorhynchus mykiss ). Recent information from UK salmonid farms showed country‐wide distribution of genetically and serologically divergent clones, which has hampered the development of a vaccine for rainbow trout fry syndrome. The current study assessed the efficacy of an injectable polyvalent vaccine containing formalin‐in...

Routine application of antimicrobials is the current treatment of choice for rainbow trout fry syndrome ( RTFS ) or bacterial coldwater disease ( BCWD ) caused by Flavobacterium psychrophilum . In this study, the antimicrobial susceptibilities of 133 F. psychrophilum isolates, 118 of which were from the UK , were evaluated by broth microdilution and disc diffusion methods following VET 04‐A2 and VET 03‐A guidelines of Clinical...

Recent work suggests that the social structure of fish shoals is nonrandom with strong tendencies for self‐sorting by phenotype in individuals of several species. The frequency of shoal encounters is high in most freshwater species but lower in pelagic fishes where intershoal distances tend to be greater. Detailed knowledge of the encounter rates between shoals and the exchange rates of individuals between shoals during encoun...

The design and operation of a grid‐net are described, which allows the capture of entire shoals of wild fish and preserves information about the two‐dimensional structure of shoals and the spatial positions of individual fish within the shoal. This simple technique facilitates investigation of several aspects of individual differences in fish shoaling behaviour in the wild for the first time.

Shoaling behaviour is generally described as a trade‐off between the anti‐predator benefits of living in groups and the costs of increased foraging competition. An individual's fitness varies as a function of shoal size and shoal composition, and this relationship is potentially body length dependent. As teleost fishes show indeterminate growth, many populations exhibit a broad range of individual body lengths. The latter is u...

Leadership is not an inherent quality of animal groups that show directional locomotion. However, there are other factors that may be responsible for the occurrence of leadership in fish shoals, such as individual differences in nutritional state between group members. It appears that front fish have a strong influence on directional shoal movements and that individuals that occupy such positions are often characterised by lar...