scholarly journals Cleaner fish escape salmon farms and hybridize with local wrasse populations

2018 ◽  
Vol 5 (3) ◽  
pp. 171752 ◽  
Author(s):  
Ellika Faust ◽  
Kim Tallaksen Halvorsen ◽  
Per Andersen ◽  
Halvor Knutsen ◽  
Carl André
Keyword(s):  
Range Expansion ◽  
First Generation ◽  
Leading Edge ◽  
Sea Lice ◽  
Fish Farms ◽  
Farmed Fish ◽  
Cleaner Fish ◽  
Local Populations ◽  
Genetic Impact ◽  
Generation Hybrid

The genetic impact of farmed fish escaping aquaculture is a highly debated issue. However, non-target species, such as cleaner fish used to remove sea lice from farmed fish, are rarely considered. Here, we report that wild corkwing wrasse ( Symphodus melops ), which are transported long distances to be used as cleaner fish in salmon farms, escape and hybridize with local populations. Recently, increasing numbers of corkwing wrasse have been reported in Flatanger in Norway, north of its described distribution range, an area heavily relying on the import of cleaner fish from Skagerrak. Using genetic markers identified with 2bRAD sequencing, we show that, although the Flatanger population largely is a result of a northward range expansion, there is also evidence of considerable gene flow from southern populations in Skagerrak and Kattegat. Of the 40 corkwing wrasses sampled in Flatanger, we discovered two individuals with clear southern genotypes, one first-generation hybrid, and 12 potential second-generation hybrids. In summary, we provide evidence that corkwing wrasse escape from fish farms and hybridize with local populations at the leading edge of an ongoing range expansion. Although the magnitude and significance of escapees warrant further investigation, these results should be taken into consideration in the use of translocated cleaner fish.

scholarly journals Sustainable production and use of cleaner fish for the biological control of sea lice: recent advances and current challenges

2018 ◽  
Vol 183 (12) ◽  
pp. 383-383 ◽  
Author(s):  
Adam J Brooker ◽  
Athina Papadopoulou ◽  
Carolina Gutierrez ◽  
Sonia Rey ◽  
Andrew Davie ◽  
...  
Keyword(s):  
Life Histories ◽  
Control Strategies ◽  
Disease Outbreaks ◽  
Basic Knowledge ◽  
Sea Lice ◽  
Suitable Habitat ◽  
Farmed Fish ◽  
Marine Aquaculture ◽  
Cleaner Fish ◽  
Labrus Bergylta

Currently, cleaner fish are one of the most widely used sea lice control strategies in Atlantic salmon aquaculture. Two species are currently being farmed in North Atlantic countries, ballan wrasse (Labrus bergylta) and lumpfish (Cyclopterus lumpus), and the sector in most countries is rapidly expanding towards self-sufficiency. The species are very different both in terms of their biology and life histories and, consequently, production and husbandry methods must be tailored to each species. There are numerous health challenges currently experienced in both species, with bacterial and parasitic diseases being the most prevalent, and cohabitation with salmon may increase the risk of disease. Good husbandry and routine health monitoring are essential, although treatment is often required when disease outbreaks occur. Ballan wrasse and lumpfish are both proven to be effective salmon delousers, although delousing efficacy can be variable in farmed fish; the provision of suitable habitat and acclimation to net-pen conditions may encourage natural behaviours, including delousing, and the use of operational welfare indicators can highlight potential welfare issues. Cleaner fish research is progressing rapidly, although much of the basic knowledge regarding the species’ biology remains unknown. The simultaneous domestication of two new marine aquaculture species is a significant challenge demanding sustained effort and funding over a prolonged period of time. Research must focus on enhancing the robustness of the farmed stocks and increasing hatchery outputs to meet the urgent demands from the salmon sector and protect wild stocks from overfishing.

scholarly journals Microsatellite-Based Genetic Structure and Hybrid Detection in Alpacas Bred in Poland

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2193
Author(s):  
Angelika Podbielska ◽  
Katarzyna Piórkowska ◽  
Tomasz Szmatoła
Keyword(s):  
Genetic Diversity ◽  
Microsatellite Markers ◽  
First Generation ◽  
Expected Heterozygosity ◽  
Hybrid Detection ◽  
Average Coefficient ◽  
Mixed Origin ◽  
Generation Hybrid

This study aimed to characterize the population structure and genetic diversity of alpacas maintained in Poland using 17 microsatellite markers recommended by the International Society for Animal Genetics. The classification of llamas, alpacas, and hybrids of both based on phenotype is often difficult due to long-term admixture. Our results showed that microsatellite markers can distinguish alpacas from llamas and provide information about the level of admixture of one species in another. Alpacas admixed with llamas constituted 8.8% of the tested individuals, with the first-generation hybrid displaying only 7.4% of llama admixture. The results showed that Poland hosts a high alpaca genetic diversity as a consequence of their mixed origin. More than 200 different alleles were identified and the average observed heterozygosity and expected heterozygosity values were 0.745 and 0.768, respectively, the average coefficient of inbreeding was 0.034, and the average polymorphism information content value was 0.741. The probability of exclusion for one parent was estimated at 0.99995 and for two parents at 0.99999.

scholarly journals Parasite induced mortality is context dependent in Atlantic salmon: insights from an individual-based model

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Knut Wiik Vollset
Keyword(s):  
Atlantic Salmon ◽  
Environmental Gradients ◽  
Population Level ◽  
Relative Effect ◽  
Host Population ◽  
Sea Lice ◽  
Fish Farms ◽  
Individual Based Model ◽  
Parasite Infestation ◽  
The Impact

AbstractAn individual-based model was parameterized to explore the impact of a crustacean ectoparasite (sea louse, Lepeophtheirus salmonis & Caligus spp.) on migrating Atlantic salmon smolt. The model explores how environmental and intrinsic factors can modulate the effect of sea lice on survival, growth and maturation of Atlantic salmon at sea. Relative to other effects, the parasite infestation pressure from fish farms and the encounter process emerge as the most important parameters. Although small variations in parasite-induced mortality may be masked by variable environmental effects, episodes of high infestation pressure from fish farms should be observable in wild populations of Atlantic salmon if laboratory studies accurately reflect the physiological effects of sea lice. Increases in temperature in the model negatively influenced fish survival by affecting the development time of the parasite at a rate that was not compensated for by the growth of the host. Discharge from rivers was parameterized to increase migration speed and influenced parasite induced mortality by decreasing time spent in areas with increased infestation pressure. Initial size and growth of the host was inversely related to the impact of the parasite because of size-dependent parasite-induced mortality in the early phase of migration. Overall, the model illustrates how environmental factors modulate effects on the host population by impacting either the parasite load or the relative effect of the parasite. The results suggest that linking population-level effects to parasite infestation pressure across climatic and environmental gradients may be challenging without correctly accounting for these effects.

scholarly journals Biofouling on Salmon Pen Nets and Cleaner Fish Shelters Does Not Harbor Planktonic Stages of Sea Lice

2020 ◽  
Vol 7 ◽  
Author(s):  
Lone S. Jevne ◽  
Margrete S. Øvrelid ◽  
Andreas Hagemann ◽  
Nina Bloecher ◽  
Kristine B. Steinhovden ◽  
...  
Keyword(s):  
Sea Lice ◽  
Cleaner Fish

scholarly journals Mycobacterium pseudoshottsii in Mediterranean Fish Farms: New Trouble for European Aquaculture?

Pathogens ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 610
Author(s):  
Davide Mugetti ◽  
Katia Varello ◽  
Andrea Gustinelli ◽  
Paolo Pastorino ◽  
Vasco Menconi ◽  
...  
Keyword(s):  
Fish Species ◽  
Sparus Aurata ◽  
Dicentrarchus Labrax ◽  
Housekeeping Genes ◽  
The United States ◽  
Sciaenops Ocellatus ◽  
Fish Farms ◽  
Farmed Fish ◽  
Potential Threat ◽  
European Aquaculture

Mycobacterium pseudoshottsii, a slow-growing mycobacterium closely related to M. marinum, has been isolated only in wild fish in the United States and in Japanese fish farms to date. Here, we report cases of mortality in three farmed fish species (Dicentrarchus labrax, Sparus aurata, and Sciaenops ocellatus) caused by M. pseudoshottsii in Italy. Samples underwent necropsy, histology, and culture with pathogen identification based on PCR and sequencing of housekeeping genes (16S rRNA, hsp65, rpoB). Multifocal to coalescing granulomatous and necrotizing inflammation with acid-fast bacilli were observed in the parenchymatous organs, from which M. pseudoshottsii was isolated and identified. Phylogenetic analysis confirmed the results of gene sequencing and allowed subdivision of the isolates into three distinct groups. M. pseudoshottsii poses a potential threat for Mediterranean aquaculture. Its origin in the area under study needs to be clarified, as well as the threat to the farmed fish species.

scholarly journals Sea-louse abundance on salmon farms in relation to parasite-control policy and climate change

2020 ◽  
Author(s):  
Sean C Godwin ◽  
Martin Krkosek ◽  
John D Reynolds ◽  
Andrew W Bateman
Keyword(s):  
Climate Change ◽  
High Temperature ◽  
Current System ◽  
Control Policy ◽  
Sea Lice ◽  
Future Climate Change ◽  
Parasite Control ◽  
Management Scenarios ◽  
Farmed Fish ◽  
Wild Salmon

Abstract The ectoparasitic copepods, sea lice (Lepeophtheirus salmonis and Caligus spp.), are major pests to salmon aquaculture and can also affect the health and survival of wild salmon. Policies exist to protect wild salmon by delousing farmed fish when louse abundance exceeds a threshold, but their effectiveness under future climate change is uncertain. We fitted a Bayesian model for sea-louse population dynamics and management to timeseries data of sea lice on farmed salmon in Pacific Canada and analysed the model under scenarios of warmer climates. We found that in high-temperature years, current parasite control policy becomes ineffective as sea-louse abundance is expected to increase. We simulated two alternative management scenarios and observed that both would decrease average louse counts on farms in high-temperature years relative to the current system but relied on more delousing treatments than are currently performed. We also found evidence that non-salmonids can play a role in louse transmission to farms, as increased farm colonization of Caligus clemensi occurs in April, coincident with wild herring (Clupea pallasii) spawner abundance. Our results highlight the need for careful management of sea lice on salmon farms in warmer years and the importance of policies designed to account for future environmental change.

scholarly journals Genetic identification of farmed and wild Atlantic cod, Gadus morhua, in coastal Norway

2011 ◽  
Vol 68 (5) ◽  
pp. 901-910 ◽  
Author(s):  
Kevin A. Glover ◽  
Geir Dahle ◽  
Knut E. Jørstad
Keyword(s):  
Case Studies ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Genetic Interactions ◽  
Genetic Identification ◽  
Fish Farms ◽  
Multiple Sources ◽  
Farmed Fish ◽  
Farmed Escapees

Abstract Glover, K. A., Dahle, G., and Jørstad, K. E. 2011. Genetic identification of farmed and wild Atlantic cod, Gadus morhua, in coastal Norway. – ICES Journal of Marine Science, 68: 901–910. Each year thousands of Atlantic cod escape from Norwegian fish farms. To investigate the potential for the genetic identification of farmed–escaped cod in the wild, three case studies were examined. Samples of farmed, recaptured farmed escapees, and wild cod were screened for ten microsatellite loci and the Pan I locus. Variable genetic differences were observed among cod sampled from different farms and cages (pairwise FST = 0.0–0.1), and in two of the case studies, the most likely farm(s) of origin for most of the recaptured escapees were identified. In case study 2, wild cod were genetically distinct from both farmed fish (pairwise FST = 0.026–0.06) and recaptured farmed–escaped cod (pairwise FST = 0.029 and 0.039), demonstrating the potential to detect genetic interactions in that fjord. Genetic identification of escapees was more challenging in case study 3, and some morphologically characterized wild cod were found to most likely represent farmed escapees. It is concluded that where cod are farmed in the same region as their own parents/grandparents were initially sourced, or where farmed escapees originate from multiple sources, quantifying genetic interactions with wild populations will be challenging with neutral or nearly neutral markers such as microsatellites.

Life in captivity: varied behavioural responses to novel setting and food types in first-generation hybrids of farmed and wild juvenile Chinook salmon (Oncorhynchus tshawytscha)

2019 ◽  
Vol 76 (11) ◽  
pp. 1962-1970
Author(s):  
Kevyn Janisse ◽  
Pauline M. Capelle ◽  
John W. Heath ◽  
Mitchel G. Dender ◽  
Daniel D. Heath ◽  
...  
Keyword(s):  
Chinook Salmon ◽  
First Generation ◽  
Oncorhynchus Tshawytscha ◽  
Juvenile Fish ◽  
Farmed Fish ◽  
Behavioural Responses ◽  
Growth Metrics ◽  
In Captivity ◽  
Behavioural Phenotypes ◽  
Response To Change

Aquaculture practices continuously seek to improve efficiency to produce larger fish at lower cost. Selective breeding within brood stocks can result in undesirable effects, promoting hatcheries to use outbreeding to increase or maintain genetic diversity. This practice however, could result in the introduction of wild behavioural phenotypes unable to adapt to captive-living conditions. Using four hatchery first-generation hybrid crosses and two fully domesticated stocks of Chinook salmon (Oncorhynchus tshawytscha) in British Columbia, we examined behavioural responses to common aquaculture practices such as abrupt environmental change and novel feed types in juvenile fish. Controlling for mass, we found crosses varied in their behaviours to a novel setting and preferences for natural versus commercial diets. These differences were furthermore associated with rearing environment and stock-level growth rate and body size. Our results suggest selecting for phenotypes that behaviourally exhibit better coping mechanisms and greater flexibility in response to change is possible, and when in combination with growth metrics, should be an integral part of producing the desired farmed fish. Behaviours that allow commercial anadromous fish to easily transition to captive environmental conditions can benefit production and also animal welfare.

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