J Fish Dis. 2019;42:1057–1064. wileyonlinelibrary.com/journal/jfd | 1057 © 2019 John Wiley & Sons Ltd 1 | INTRODUCTION Even though globally aquaculture is the fastest‐growing food‐pro‐ duction industry (FAO, 2018), parasitic diseases, like sea lice infes‐ tation (Lepeophtheirus salmonis, Caligus elongatus, etc.), plague this sector (Fisheries & Oceans Canada, 2017; Stentiford et al., 2017; Wootten, Smith, & Needham, 2011). Sea–lice is the greatest health challenge limiting production of the Canadian Atlantic salmon (Salmo salar) aquaculture industry since the 1970s (Brandal & Egidius, 1977; Fisheries & Oceans Canada, 2013; Mustafa, Rankaduwa, & Campbell, 2001; Nilsen, Nielsen, Biering, & Bergheim, 2017; Powell et al., 2018; Torrissen et al., 2013). Sea–lice is a copepod ectopara‐ site (Aaen, Helgesen, Bakke, Kaur, & Horsberg, 2015; Hamre et al., 2013; Nilsen et al., 2017; Wootten, Smith, & Needham, 2011) that immune compromises the fish host, increasing susceptibility to viral and bacterial infections (Brooker et al., 2018) and causing signifi‐ cant losses and high treatment costs (Costello, 2009; Fisheries & Oceans Canada, 2017). It has been estimated that sea–lice infec‐ tion results in up to a 16% reduction in production biomass, which is approximately equivalent to a 9% loss in farm revenues (Abolofia, Wilen, & Asche, 2017). Several pest control strategies have been developed over the years, including physical removal technologies (e.g., brushes, water jets and osmolarity shock treatments), feed ad‐ ditives, selective breeding¸ and chemotherapeutants that are losing their efficacy due to evolved parasitic resistance (Aaen et al., 2015; Torrissen et al., 2013). Received: 20 February 2019 | Revised: 4 April 2019 | Accepted: 6 April 2019 DOI: 10.1111/jfd.13010 ORIGINAL ARTICLE Vibrogen‐2 vaccine trial in lumpfish ( Cyclopterus lumpus ) against Vibrio anguillarum Setu Chakraborty 1 | Trung Cao 1 | Ahmed Hossain 1 | Hajarooba Gnanagobal 1 | Ignacio Vasquez 1 | Danny Boyce 2 | Javier Santander 1 1 Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Faculty of Science, Memorial University of Newfoundland, St John’s, Newfoundland, Canada 2 Dr. Joe Brown Aquatic Research Building, Department of Ocean Sciences, Memorial University of Newfoundland, St John’s, Newfoundland, Canada Correspondence Javier Santander, Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Faculty of Science, Memorial University of Newfoundland, 0 Marine Lab Road, St John’s, NL A1C 5S7, Canada. Email: jsantander@mun.ca Funding information MUN Seed, Bridge and Multidisciplinary Funds; Canada First Research Excellence Fund ‐ Ocean Frontier Institute; Natural Sciences and Engineering Research Council of Canada Abstract Lumpfish (Cyclopterus lumpus), a native fish of the North Atlantic Ocean, is utilized as cleaner fish to biocontrol sea lice infestations in Atlantic salmon aquaculture. However, bacterial infections are affecting cleaner fish performance. Vibrio anguil- larum, the aetiological agent of vibriosis, is one of the most frequent bacterial infec‐ tions in lumpfish, and effective vaccine programmes against this pathogen have been identified as a high priority for lumpfish. Vibrogen‐2 is a commercial polyvalent bath vaccine that contains formalin‐inactivated cultures of V. anguillarum serotypes O1 and O2, and Vibrio ordalii. In this study, we evaluated Vibrogen‐2 efficacy in lump‐ fish against a local isolated V. anguillarum strain. Two groups of 125 lumpfish were bath‐immunized, bath‐boost‐immunized at four weeks post‐primary immunization, and intraperitoneally (i.p.) boost‐immunized at eight weeks post‐primary immuniza‐ tion. The control groups were i.p. mock‐immunized with PBS. Twenty‐seven weeks post‐primary immunization, the fish were i.p. challenged with 10 or 100 times the V. anguillarum J360 LD 50 dose. After the challenge, survival was monitored daily, and samples of tissues were collected at ten days post‐challenge. Commercial vaccine Vibrogen‐2 reduced V. anguillarum tissue colonization and delayed mortality but did not confer immune protection to C. lumpus against the V. anguillarum i.p. challenge. KEYWORDS cleaner fish, lumpfish, vaccine, Vibrio anguillarum, Vibrogen‐2