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The commercialization of a new species through aquaculture is much more complex than the mastery of the production process, or closing the loop, as it is sometimes referred to. Commercial aquaculture is a layer within the global seafood industry, much as wild capture is; however, it places human control at a much earlier phase in the life cycle of the harvested product. As an important species on both sides of the Atlantic, the commercialization efforts for the culture of Atlantic cod are described for four locations, Norway, United Kingdom, New England, and Atlantic Canada that highlight many similar technical challenges and the progress made from the late 1980s through 2012. We also describe some of the marketing challenges faced and how they differ. Technically, the species has been commercialized. Hatcheries and farms in all four countries were successfully established. However, there are clear differences in access to capital for research and industrial expansion from both the private and public sector, social acceptance of farmed fish, as well as the impacts on sales when marketing farmed cod in the context of a global seafood supply. Lower cost species substitution, from either the farmed or wild catch, is also a factor that can have a significant impact on long-term successful commercialization.

Immune responses to infectious diseases impacting lumpfish (Cyclopterus lumpus) eye tissue are only starting to be studied at a molecular and histopathological level. In this study, we extend our understanding of lumpfish sensory organ anatomy, of components of the lumpfish nasal and ocular immune system and the nature of the intraocular response to Vibrio anguillarum infection. We have evaluated the expression of cluster of differentiation (CD) 45 protein, a tyrosine phosphatase, in larval and juvenile lumpfish tissues in order to spatially survey ocular and related head structures that may participate in early stages of intraocular immune responses. We provide here a histological mapping of the larval lumpfish nasal chamber system since its connectively with the eye though mucosal epithelia have not been explored. These results build upon our growing understanding of the lumpfish intraocular immune response to pathogens, exemplified herein by experimental nasally delivered V. anguillarum infection. CD45 is developmentally regulated in lumpfish eyes and periocular anatomy with early expression appearing in larvae in corneal epithelium and in nasal structures adjacent to the eye. Normal juvenile and adult lumpfish eyes express CD45 in the corneal epithelium, in leukocyte cells within blood vessel lumens of the rete mirabile, choroid body and choriocapillaris vasculatures. Experimental nasally delivered V. anguillarum infection led to qualitative and quantitative changes in CD45 expression in head kidney renal tubule tissues by 7 days post infection (dpi). The same animals showed redistribution and upregulation of corneal epithelial CD45 expression, corneal epithelial dysplasia and an increased frequency of CD45

Teleosts exhibit extensive diversity of sex determination (SD) systems and mechanisms, providing the opportunity to study the evolution of SD and sex chromosomes. Here we sequenced the genome of the common lumpfish (Cyclopterus lumpus Linnaeus), a species of increasing importance to aquaculture, and identified the SD region and master SD locus using a 70 K single nucleotide polymorphism array and tissue-specific expression data. The chromosome-level assembly identified 25 diploid chromosomes with a total size of 572.89 Mb, a scaffold N50 of 23.86 Mb and genome annotation-predicted 21,480 protein-coding genes. Genome-wide association analysis located a highly sex-associated region on chromosome 13, suggesting that anti-Müllerian hormone (AMH) is the putative SD factor. Linkage disequilibrium and heterozygosity across chromosome 13 support a proto-XX/XY system, with an absence of widespread chromosome divergence between sexes. We identified three copies of AMH in the lumpfish primary and alternate haplotype assemblies localized in the SD region. Comparison to sequences from other teleosts suggested a monophyletic relationship and conservation within the Cottioidei. One AMH copy showed similarity to AMH/AMHY in a related species and was also the only copy with expression in testis tissue, suggesting this copy may be the functional copy of AMH in lumpfish. The two other copies arranged in tandem inverted duplication were highly similar, suggesting a recent duplication event. This study provides a resource for the study of early sex chromosome evolution and novel genomic resources that benefits lumpfish conservation management and aquaculture.

Lumpfish use their vision to hunt prey or, in the case of aquaculture, to see and eat pelleted diets. A common anterior ocular opacity abnormality designated in the literature as "cataract" described in both farmed and wild lumpfish has not yet been characterized in detail at the pathobiological level. We describe here lens tissue changes associated with cataract in cultured and domesticated lumpfish. Methodology included gross observations, ophthalmoscopy and histology. Young adult cultured animals approaching 400 days post-hatch presented a range of anterior segment opacities associated with lenticular abnormalities observable at a histological level. Wild aged domesticated animals also displayed cataracts characterized mainly by abnormalities of the lens observed by both ophthalmoscopy and histology. Dysplastic lesions of the lens in one aged domesticated lumpfish were accompanied with both retinal and optic nerve degeneration. These novel naturally occurring anatomical changes in lumpfish present both commonalities and unique features associated with cataract in young adult cultured animals versus aged domesticated broodstock animals.

Cunner (Tautogolabrus adspersus) is a cleaner fish being considered for utilized in the North Atlantic salmon (Salmo salar) aquaculture industry to biocontrol sea lice infestations. However, bacterial diseases due to natural infections in wild cunners have yet to be described. This study reports the isolation of Pseudomonas sp. J380 from infected wild cunners and its phenotypic, genomic, and transcriptomic characterization. This Gram-negative motile rod-shaped bacterium showed a mesophilic (428 °C) and halotolerant growth. Under iron-limited conditions, Pseudomonas sp. J380 produced pyoverdine-type fluorescent siderophore. Koch’s postulates were verified in wild cunners by intraperitoneally (i.p.) injecting Pseudomonas sp. J380 at 4 × 103, 4 × 105, and 4 × 107 colony forming units (CFU)/dose. Host-range and comparative virulence were also investigated in lumpfish and Atlantic salmon i.p. injected with ~106 CFU/dose. Lumpfish were more susceptible compared to cunners, and Atlantic salmon was resistant to Pseudomonas sp. J380 infection. Cunner tissues were heavily colonized by Pseudomonas sp. J380 compared to lumpfish and Atlantic salmon suggesting that it might be an opportunistic pathogen in cunners. The genome of Pseudomonas sp. J380 was 6.26 megabases (Mb) with a guanine-cytosine (GC) content of 59.7%. Biochemical profiles, as well as comparative and phylogenomic analyses, suggested that Pseudomonas sp. J380 belongs to the P. fluorescens species complex. Transcriptome profiling under iron-limited vs. iron-enriched conditions identified 1159 differentially expressed genes (DEGs). Cellular metabolic processes, such as ribosomal and energy production, and protein synthesis, were impeded by iron limitation. In contrast, genes involved in environmental adaptation mechanisms including two-component systems, histidine catabolism, and redox balance were transcriptionally up-regulated. Furthermore, iron limitation triggered the differential expression of genes encoding proteins associated with iron homeostasis. As the first report on a bacterial infection in cunners, the current study provides an overview of a new marine pathogen, Pseudomonas sp. J380.

Lumpfish (Cyclopterus lumpus), a North Atlantic “cleaner“ fish, is utilized to biocontrol salmon louse (Lepeophtheirus salmonis) in Atlantic salmon (Salmo salar) farms. Lumpfish require excellent vision to scan for and eat louse on salmon skin. The lumpfish eye immune response to infectious diseases has not been explored. We examined the ocular response to a natural parasite infection in wild lumpfish and to an experimental bacterial infection in cultured lumpfish. Cysts associated with natural myxozoan infection in the ocular scleral cartilage of wild adult lumpfish harbored cells expressing cluster of differentiation 10 (CD10) and immunoglobulin M (IgM). Experimental Vibrio anguillarum infection, which led to exophthalmos and disorganization of the retinal tissues was associated with disruption of normal CD10 expression, CD10+ cellular infiltration and IgM expression. We further describe the lumpfish CD10 orthologue and characterize the lumpfish scleral skeleton in the context of myxozoan scleral cysts. We propose that lumpfish develop an intraocular response to pathogens, exemplified herein by myxozoan and V. anguillarum infection involving novel CD10+ cells and IgM+ cells to contain and mitigate damage to eye structures. This work is the first demonstration of CD10 and IgM expressing cells in a novel ocular immune system component in response to disease in a teleost.

Vibrio anguillarum is a Gram-negative marine pathogen causative agent of vibriosis in a wide range of hosts, including invertebrates and teleosts. Lumpfish (Cyclopterus lumpus), a native fish of the North Atlantic Ocean, is utilized as cleaner fish to control sea lice (Lepeophtheirus salmonis) infestations in the Atlantic salmon (Salmo salar) aquaculture industry. V. anguillarum is one of the most frequent bacterial pathogens affecting lumpfish. Here, we described the phenotype and genomic characteristics of V. anguillarum strain J360 isolated from infected cultured lumpfish in Newfoundland, Canada. Koch&rsquo, s postulates determined in na&iuml, ve lumpfish showed lethal acute vibriosis in lumpfish. The V. anguillarum J360 genome was shown to be composed of two chromosomes and two plasmids with a total genome size of 4.56 Mb with 44.85% G + C content. Phylogenetic and comparative analyses showed that V. anguillarum J360 is closely related to V. anguillarum strain VIB43, isolated in Scotland, with a 99.8% genome identity. Differences in the genomic organization were identified and associated with insertion sequence elements (ISs). Additionally, V. anguillarum J360 does not possess a pJM1-like plasmid, typically present in virulent isolates from the Pacific Ocean, suggesting that acquisition of this extrachromosomal element and the virulence of V. anguillarum J360 or other Atlantic isolates could increase.

Vibrio anguillarum, a marine bacterial pathogen that causes vibriosis, is a recurrent pathogen of lumpfish (Cyclopterus lumpus). Lumpfish is utilized as a cleaner fish in the Atlantic salmon (Salmo salar) aquaculture in the North Atlantic region because of its ability to visualize and prey on the ectoparasite sea lice (Lepeophtheirus salmonis) on the skin of Atlantic salmon, and its performance in cold environments. Lumpfish immunity is critical for optimal performance and sea lice removal. Oral vaccine delivery at a young age is the desired method for fish immunization because is easy to use, reduces fish stress during immunization, and can be applied on a large scale while the fish are at a young age. However, the efficacy of orally delivered inactivated vaccines is controversial. In this study, we evaluated the effectiveness of a V. anguillarum bacterin orally delivered to cultured lumpfish and contrasted it to an intraperitoneal (i.p.) boost delivery. We bio-encapsulated V. anguillarum bacterin in Artemia salina live-feed and orally immunized lumpfish larvae. Vaccine intake and immune response were evaluated by microscopy and quantitative polymerase chain reaction (qPCR) analysis, respectively. qPCR analyses showed that the oral immunization of lumpfish larvae resulted in a subtle stimulation of canonical immune transcripts such as il8b, il10, igha, ighmc, ighb, ccl19, ccl20, cd8a, cd74, ifng, and lgp2. Nine months after oral immunization, one group was orally boosted, and a second group was both orally and i.p. boosted. Two months after boost immunization, lumpfish were challenged with V. anguillarum (7.8 × 105 CFU dose−1). Orally boosted fish showed a relative percentage of survival (RPS) of 2%. In contrast, the oral and i.p. boosted group showed a RPS of 75.5% (p &lt, 0.0001). V. anguillarum bacterin that had been orally delivered was not effective in lumpfish, which is in contrast to the i.p. delivered bacterin that protected the lumpfish against vibriosis. This suggests that orally administered V. anguillarum bacterin did not reach the deep lymphoid tissues, either in the larvae or juvenile fish, therefore oral immunization was not effective. Oral vaccines that are capable of crossing the epithelium and reach deep lymphoid tissues are required to confer an effective protection to lumpfish against V. anguillarum

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 anguillarum, the aetiological agent of vibriosis, is one of the most frequent bacterial infections 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 lumpfish 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 immunization. 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 LD50 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.

We examined the effects of partial dietary supplementation with wild zooplankton or fish protein hydrolysate on cod production traits, and how they related to the expression of growth and appetite regulating transcripts and muscle cellularity. Atlantic cod larvae were fed three different diets: enriched rotifers and Artemia (RA); RA + fish protein hydrolysate (RA-PH); and RA supplemented with 5–10% wild zooplankton (RA-Zoo). Partial supplementation with zooplankton significantly improved cod dry weight at 60 days post-hatch (by approximately 4-fold), specific growth rate (by 2.5% day − 1 ) and the general development of cod larvae. Although the zooplankton fed cod were still larger at approximately 1.5 years of age, the growth advantage of this group decreased with age (the difference in wet mass decreasing from approximately 30% at 0.5 years old to 11% at 1.5 years old). In contrast, the protein hydrolysate enrichment did not improve growth, had a negative effect on survival, and increased the incidence of external deformities in 1.5 year old fish. The growth enhancement observed in the RA-Zoo larvae was largely unrelated to differences in the transcript levels of several important growth [Insulin-Like Growth Factor 1 ( igf-1 ); igf-2 ; Growth Hormone ( gh ); GH Receptor-1 ( ghr-1 ); ghr-2 ; and myostatin ( mstn )] or appetite regulating genes [Cocaine and Amphetamine Regulated Transcript ( cart) and Neuropeptide Y ( npy )], but was associated with an increase in the number and size of skeletal muscle fibers. Our findings suggest that incorporating small amounts of wild zooplankton into larval feeding regimes may significantly enhance the production of marine fishes, but that the transcript levels of the above hormones and hormone receptors are not valuable biomarkers of growth in cod larvae. Statement of relevance This research shows that small amounts of zooplankton significantly improve the growth of Atlantic cod larvae, and thus, that cultured zooplankton may be a viable and cost-effective strategy for increasing the growth (and potentially health) of intensively cultured marine finfishes.

We systematically analysed the characteristics of the Cyclopterus lumpus eye and retina during cultured post-hatch developmental stages using gross observations, histology, immunohistochemistry, microscopy, fundus imaging and spectral domain optical coherence tomography retinal imaging. Post-hatch developing cultured C. lumpus eye and retinal tissues share a number of features typically conserved in other teleost fish. However, cultured C. lumpus possess some novel ocular and retinal features different from previous descriptions of other teleosts, including a prominent retractor lentis pigmented tissue closely associated with the vascular rete mirabile, peripherally located lobes of separate retinal tissue containing proliferative cells, extensive tapetum material of varying thickness, prominent fundus stripes and an elongated rod-shaped optic nerve stalk. Post-hatch developing cultured C. lumpus also developmentally regulate a protein homologous to alpha smooth-muscle actin in strikingly dense continuous bands in the plexiform layers of the retina. The novel features of the eye and retina of cultured C. lumpus described here could contribute to our understanding of fitness and survival of C. lumpus in a widely ranging habitat.

Atlantic Cod (Gadus morhua L.) represents an attractive species for cold water aquaculture. However, like many so called 'alternative species' early larval culture remains a challenge to commercial production. Indeed in comparison to other cultured finfish species, there exists limited information concerning the bacterial species associated with cod larviculture. Herein, we have employed PCR amplification of 16S rDNA coupled to Denaturing Gradient Gel Electrophoresis (DGGE) and sequencing of isolated amplicons, to profile the bacterial species associated with cod (both eggs and larvae) and the live feed (rotifer and Artemia) provided to the larvae during the first 50 days of development. A stable core microflora, comprising a total of six bacterial species with a putative Arcobacter sp. as the dominant component, was recorded in the majority of the rotifer samples. In contrast, Artemia showed a highly variable microflora composed of Vibrio spp, Alteromonas spp and Pseudoalteromonas spp. An association between Colwellia spp and cod eggs was demonstrated, although these species rapidly disappeared from the larval microflora which subsequently showed a reproducible (in 6 tanks over 2 years), and well-defined bacterial succession. Vibrio logei, V.fischeri and Listonella anguillarum predominated during the first 3 weeks of feeding but were gradually replaced by Flexibacter aurantiacus, a species of Sulfitobacter, and a putative Mycoplamsa sp. At 50 days post feeding the putative Mycoplasma sp. emerged as the dominant component of the microflora in all tanks. The culture-independent approach employed in this study generated a dynamic description of bacterial colonization of cod larvae and live feed and revealed the existence of previously undescribed bacterial associations with eggs and rotifers which would almost certainly have gone undetected using conventional culture based methods.

Yellowtail flounder, Limanda ferruginea (Storer, 1839), is a highly marketable fish species that used to be a significant groundfish in the northwest Atlantic region. The potential of yellowtail flounder for mass rearing has recently been investigated, but studies into aspects of mortality during early ontogeny are lacking. We investigated the impact of spawning inducement on mortality of eggs from fertilisation until hatch, and the effects of rearing temperature on mortality and hatching time in this multiple batch spawning flounder. An ash-free dry mass (AFDM) technique for determining mortality was employed. This technique reduced rearing tank disturbances and provided quantitative mortality estimates. We found (1) that spontaneously ovulated (SO) mean egg mass (AFDM 24.84 ± 0.73 μg) was significantly higher than mean egg mass from induced ovulation (IO) (AFDM 20.09 ± 0.54 μg); (2) that mortality of SO eggs was lower than IO eggs (p = 0.028), (3) that SO eggs reached a relatively constant (maximum) mortality by about day 3 and IO eggs by about day 5; (4) that there was no significant difference in mortality between eggs incubated at 10 °C and those incubated at 4 °C (p = 0.320); and (5) that time to 100% hatch took significantly longer for eggs incubated at 4 °C (256.0 ± 73.5 h) than those incubated at 10 °C (77.9 ± 11.6 h) (p = 0.003). There was considerable variation in egg mortality among batches and females; nevertheless, general trends indicate that GnRHa-induction of ovulation tends to decrease egg quality. In addition, the AFDM technique was an easily employed and accurate method of determining mortality. We recommend that unless coordination of spawning is important to a particular rearing protocol, induced ovulation should not be employed.

Several studies have shown that food ration can affect the growth of cultured fish. Determining the optimal food ration would help to achieve better growth and also provide direct economic benefits due to reduced food wastage, which would lead to commercial success. Therefore, we studied the effects of ration levels on growth performance of 0 + juvenile yellowtail flounder to determine the optimal food ration. Two experiments were conducted; the first experiment as a preliminary using ration levels of 1%, 2%, 4%, 6% body weight per day (% bw day −1 ) held at 7.0 °C with a stocking density of 0.95 kg m −2 (∼45% bottom coverage). Results of this preliminary experiment indicated that fish fed with 1% bw day −1 had significantly lower growth (weight, length, body depth and specific growth rates (SGR)) than those fed with 2%, 4% and 6% ration. However, fish fed with rations of 1% and 2% showed significantly lower gross food conversion ratios (GFCR) than fish fed with 4% and 6% rations. Survival was not significantly affected by different ration levels. Based on these preliminary results, we used ration levels of 1%, 1.5%, 2% and 3% for the main experiment. Fish were held at 10 °C with a stocking density of 1.45 kg m −2 (∼34% bottom coverage). Results indicated that fish fed with 1%, 1.5% and 2% bw day −1 had significantly lower growth than fish fed with 3% bw day −1 . GFCR was significantly different for all four rations. It was lower for 1% than 1.5%, 2% and 3% rations. Survival was not significantly different between any treatments. We discuss our results with emphasis on growth and economics (i.e., feed wastage) and stress the need to balance both components in a commercial operation.

4-yr.-olds, 18 girls and 18 boys, either imitated or failed to imitate a sequence of modeled acts. Children who imitated at least one modeled act showed higher self-concept scores following modeling than those children who failed to imitate. Imitators vs non-imitators did not differ in their self-concept scores prior to modeling. Results were discussed in terms of a competence model.