New study reveals intriguing information about inquisitive UK fish

The discovery of distinctive face markings on one of the UK’s most charismatic and inquisitive fish has enabled an underwater photographer to reveal intriguing new information about its behaviour.

Paul Naylor has been studying tompot blennies for many years, undertaking more than 100 dives at particular spots in Devon. He recently discovered, thanks to his library of close-up photographs, that each fish has distinctive face markings, allowing him to get to know individual blennies.

Paul said:  ‘Before discovering the distinctive facial markings, it wasn’t possible to interpret whether interactions between tompot blennies were territorial disputes or courtship. Being able to identify individual fish leads to much better recording and a greater understanding of their behaviour.’

Paul determined that a male tompot blenny, as found on shallow rocky reefs around Britain, can live in the same crevice in the rock for up to four years. Paul now knows he witnessed males encouraging females—not just one but many—and over subsequent breeding seasons, to lay eggs which the male guarded from all predators, such as other fish and crabs, until the eggs hatched. 

Paul identified males having disputes over territory, with one individual seen recovering from injuries endured in the fights. Juvenile tompot blennies learn the ways of adulthood quickly, with even the youngest fish having stand-offs. Through photo identification, Paul also recorded a highly unusual aspect of blenny behaviour close to the Dorset coast; a large male tompot followed winning a territorial fight, by pushing a large shell around the seabed ‘showing off’ to two smaller tompots.

Paul adds:  ‘I hope the results of this study will help to illustrate the awesome antics going on in UK waters and how important it is for us to protect them for the future.’

Joan Edwards, The Wildlife Trusts’ head of Living Seas, said:  ‘The photo identification of fish is very unusual as they are generally perceived to be all the same and lacking in character.  However, through his underwater photography, Paul has helped The Wildlife Trusts over many years to inspire people about the many charismatic creatures we do have in UK seas, including the clown-like tompot blenny.’ 

The result of Paul’s research, along with David Jacoby of ZSL, are published in the Journal of Fish Biology:  P. Naylor and D. M. P Jacoby: Territoriality in the tompot blenny Parablennius  gattorugine from photographic records. Journal of Fish Biology 2016; DOI 10.1111/jfb.12918.