“We have to improve our understanding of lumpfish in the wild,” argued Kirstin Eliasen, from Fiskaaling, at today’s International Cleaner Fish Conference in Glasgow. “We can’t make all our assumptions about their behaviour based on lumpfish in captivity – it’s the greatest knowledge gap we have at the moment in my opinion,” she added.
The theme was central to a discussion on how to improve the efficacy of cleanerfish – a topic that encouraged lively debate and exposed a number of fundamental holes in scientific research.
“We still don’t know why lumpsuckers eat sea lice,” observed Kjell Maroni of FHF, “…and we don’t even know if they feed on sight or by smell.”
“If we could find this out it would help [make them more effective cleaners],” he added.
“It must be pure instinct,” argued Jónas Jónasson, of StofnFiskur, “surely lumpfish are working as cleanerfish in the wild?” he added.
“They have all the protective mechanisms to be a cleanerfish – they are spiky, ugly and taste bad – who wants to eat them?” he quipped.
The discussion that ensued covered how lumpsuckers are not true cleanerfish, like wrasse, but are purely opportunists. However, the fact that they are regularly caught as by-catch in the nets of salmon fishermen, suggests that they do co-habit with salmonids naturally. Moreover, the fact that they are shown to eat lice without much persuasion in culture conditions suggests that they are not strangers to picking parasites off wild fish – be they salmonids or other pelagic species such as herring or mackerel.
However, there is little documentation of such behaviour, leading to several delegates suggesting the need for further research into this area. Equally, given that a huge range in louse eating ability has been documented amongst individual lumpfish, it is clear that more research is required into why some individuals seem to have a great appetite for parasites than others.
“Why do we find 500-600 lice in some individuals and none in others?” asked Maroni.
It was one of the key questions that the 3-day event, which was organised by SAIC and FHF, will hopefully help to inspire an answer to.