Cleaner fish in aquaculture: review on diseases and vaccination

Abstract

Combating and controlling sea lice causes large economic costs for the farmers, with estimated values of more than 305 million euros (€) per year. Increased resistance against traditional chemotherapeutants due to evolutionary drivers in the sea lice combined with the lack of an effective vaccine and few other chemical treatments available are expected to cause these costs to increase. Several possible methods for managing sea lice infestations have been investigated, but only cleaner fish has proven to have an effect on lice levels. Cleaning activity is well known in marine fish and has been observed in the wild as a form of symbiosis between two species: one species, the 'client' fish, seek out the other species, the 'cleaner' fish, to have ectoparasites and dead tissue cleared from its body. The Atlantic lumpfish is a relatively new aquaculture species, and wild-caught mature fish are used as brood stock for farmed production. This poses a biosecurity risk, as wild fish can carry pathogens, and the use of quarantine and health screening is recommended. Vaccine development is unfortunately lagging far behind relatively to the wide spread and high utilisation of the fish. This review contains description of the main pathogens and diseases that affect cleaner fish.

Factors associated with baseline mortality in Norwegian Atlantic salmon farming

“…Co-stocking cleaner fish with salmon failed to reduce sea lice counts 66 , whereas others found high reduction (60–100%) in adult female lice counts compared with sea cages without cleaner fish 67 . It is noteworthy that the negative impacts of using cleaner fish, especially wild-caught wrasse, has been debated, due to the potential introduction and exchange of pathogens between different fish species stocked in the same sea cages 4 , 68 . In addition, the mortality of cleaner fish during their time spent in sea cages with the Atlantic salmon is extremely high.…”

A Novel Marine Pathogen Isolated from Wild Cunners (Tautogolabrus adspersus): Comparative Genomics and Transcriptome Profiling of Pseudomonas sp. Strain J380

“…The mutually beneficial cleaner fish—salmonid association reduces the parasite burden on salmonids while providing a food source to cleaner fish. In salmonid aquaculture, different wrasse (e.g., rock cook ( Centrolabrus exoletus ), goldsinny ( Ctenolabrus rupestris ), cuckoo ( Labrus mixtus ), ballan ( Labrus bergylta ), and corkwing ( Symphodus melops ) and lumpfish ( Cyclopterus lumpus ) species are used [ 8 , 9 , 10 ]. Wrasses and lumpfish possess contrasting season-dependent feeding behaviors.…”

Oral Immunization of Larvae and Juvenile of Lumpfish (Cyclopterus lumpus) against Vibrio anguillarum Does Not Influence Systemic Immunity

“…Similar to other finfish species, lumpfish is susceptible to different types of bacterial pathogens such as Aeromonas salmonicida , Pasteurella spp., Tenacibaculum spp., Pseudomonas anguilliseptica , and Moritella viscosa [ 21 , 22 ]. Vibriosis, typically caused by Vibrio anguillarum , is a prevalent pathogen in lumpfish in Newfoundland [ 23 ], but others such as V. ordalii , V. salmonicida , and V. splendidus also infect lumpfish elsewhere [ 12 , 24 ]. V. anguillarum is a Gram-negative, motile, rod-shaped bacterium and a ubiquitous marine pathogen of invertebrates and vertebrates [ 25 , 26 ].…”