scholarly journals Implications of Entry Restrictions to Address Externalities in Aquaculture: The Case of Salmon Aquaculture

2020 ◽  
Vol 77 (4) ◽  
pp. 673-694
Author(s):  
Atle Oglend ◽  
Vesa-Heikki Soini

AbstractThis paper investigates production license management when regulation constrains the number of production licenses to address production externalities. This is increasingly relevant for aquaculture production where disease issues threaten future seafood supply. The regulatory problem is analyzed in the context of Norwegian salmon aquaculture where a stop in issuance of new production licenses has been implemented to address social costs of parasitic sea lice. Our theoretical model shows that restricting number of licenses raises prices and shifts production efforts excessively towards greater stocking of fish per license. Hence, the policy cannot achieve a first-best welfare-maximizing allocation. Furthermore, restricting entry by limiting number of licenses can create regulatory rents, which effectively subsides rather than tax the source of the externality.

2013 ◽  
Vol 34 (1) ◽  
pp. 109-119 ◽  
Author(s):  
Jakub M. Gac ◽  
Leon Gradoń

Abstract A simple model of behaviour of a single particle on the bulging membrane was presented. As a result of numerical solution of a motion equation the influence of the amplitude and frequency of bulging as well as the particle size on particle behaviour, especially its downstream velocity was investigated. It was found that the bulging of a membrane may increase the mean velocity of a particle or reinforce its diffusive behaviour, dependeing on the permeation velocity. The obtained results may help to design new production methods of highly fouling-resistant membranes.


2020 ◽  
Vol 12 ◽  
pp. 31-44 ◽  
Author(s):  
K Overton ◽  
LT Barrett ◽  
F Oppedal ◽  
TS Kristiansen ◽  
T Dempster

2021 ◽  
pp. 251484862110606
Author(s):  
Nicole Power ◽  
Jessica Melvin ◽  
Charles Mather

Research in animal geographies is increasingly paying attention to hierarchies and inequalities within and between nonhuman animals. The way that animals are valued differently and hierarchically within this growing body of scholarship has tended to focus on a range of biopolitical differences between and within species. Collard and Dempsey’s recent contribution, in contrast, points to the importance of hierarchy and difference in the valuation of nonhuman animals under capitalism. Their framework identifies five orientations of human and nonhuman bodies in relation to capitalist value, which in turn provides a heuristic to explore how capitalist accumulation produces and depends on differentially oriented natures. Our contribution to these debates – and to the Collard and Dempsey framework – draws on our ongoing research in Eastern Canada where salmon aquaculture is a growing yet highly contested industry. We focus on two instances of multispecies hierarchy and difference in and around the salmon cage that are central to this form of ocean-based production. In focusing on multispecies relations, we build on Collard and Dempsey's framework in two main ways. First, we show how valuation and devaluation reflect competing but relational capitalist interests, which rely on and produce different natures refracted through the logic of the nature/culture divide: Atlantic salmon are valued as game fish, and as the key species for Canada's aquaculture sector. Second, we show how capital's valuation of one species, in our case farmed salmon, implicates the valuation of others, namely sea lice and lumpfish. Our case studies extend Collard and Dempsey's framework by demonstrating how capitalist differentiation produces violence through and outside of commodification in terms of multispecies difference and hierarchy; the lives and futures of wild and farmed salmon, lumpfish and sea lice are entangled, and reflect relational and changing orientations to capitalist value over time.


2016 ◽  
Vol 371 (1689) ◽  
pp. 20150203 ◽  
Author(s):  
Maya L. Groner ◽  
Luke A. Rogers ◽  
Andrew W. Bateman ◽  
Brendan M. Connors ◽  
L. Neil Frazer ◽  
...  

Effective disease management can benefit from mathematical models that identify drivers of epidemiological change and guide decision-making. This is well illustrated in the host–parasite system of sea lice and salmon, which has been modelled extensively due to the economic costs associated with sea louse infections on salmon farms and the conservation concerns associated with sea louse infections on wild salmon. Consequently, a rich modelling literature devoted to sea louse and salmon epidemiology has been developed. We provide a synthesis of the mathematical and statistical models that have been used to study the epidemiology of sea lice and salmon. These studies span both conceptual and tactical models to quantify the effects of infections on host populations and communities, describe and predict patterns of transmission and dispersal, and guide evidence-based management of wild and farmed salmon. As aquaculture production continues to increase, advances made in modelling sea louse and salmon epidemiology should inform the sustainable management of marine resources.


2008 ◽  
Vol 4 (5) ◽  
pp. 455-457 ◽  
Author(s):  
B.M Connors ◽  
M Krkošek ◽  
L.M Dill

Parasites seldom have predators but often fall victim to those of their hosts. How parasites respond to host predation can have important consequences for both hosts and parasites, though empirical investigations are rare. The exposure of wild juvenile salmon to sea lice ( Lepeophtheirus salmonis ) from salmon farms allowed us to study a novel ecological interaction: the response of sea lice to predation on their juvenile pink and chum salmon hosts by two salmonid predators—coho smolts and cut-throat trout. In approximately 70% of trials in which a predator consumed a parasitized prey, lice escaped predation by swimming or moving directly onto the predator. This trophic transmission is strongly male biased, probably because behaviour and morphology constrain female movement and transmission. These findings highlight the potential for sea lice to be transmitted up marine food webs in areas of intensive salmon aquaculture, with implications for louse population dynamics and predatory salmonid health.


Author(s):  
Samuel Shephard ◽  
Patrick Gargan

Abstract Impacts on marine survival of Atlantic salmon Salmo salar include sea lice Lepeophtheirus salmonis infestation from coastal aquaculture, and ocean climate forcing. These effects may interact because infestation compromises smolt growth and body condition, and thus response to environmental conditions. We hypothesized that migrating smolts exposed to lice from salmon farms would show (i) reduced one sea-winter (1SW) returns to natal rivers and (ii) a shift in relationships between ocean climate and returns. Annual counts of 1SW fish were studied from ten rivers in Ireland, including five “control” systems without salmon aquaculture. Most counts showed a downward trend, consistent with declines in Atlantic salmon populations. Rivers with aquaculture showed lesser returns (mean 33%, range 19–46%) in years following high lice levels on nearby salmon farms. The level of likely lice pressure also modified how annual 1SW returns varied with ocean conditions. Returns to control rivers showed a weak negative relationship with the Atlantic Multi-decadal Oscillation (AMO) in the late summer (September) of the out-migrating year. This negative AMO effect became much stronger for fish migrating in low lice years but was not evident for high lice years. Smolts experiencing mild-to-moderate lice infestation may show greater sensitivity to ocean warming.


2020 ◽  
Vol 12 (4) ◽  
pp. 2527-2543 ◽  
Author(s):  
Luke T. Barrett ◽  
Frode Oppedal ◽  
Nick Robinson ◽  
Tim Dempster

Author(s):  
Gaspard Philis ◽  
Friederike Ziegler ◽  
Mona Dverdal Jansen ◽  
Lars Christian Gansel ◽  
Sara Hornborg ◽  
...  

2019 ◽  
Vol 11 ◽  
pp. 507-519 ◽  
Author(s):  
ML Groner ◽  
E Laurin ◽  
M Stormoen ◽  
J Sanchez ◽  
MD Fast ◽  
...  
Keyword(s):  
Sea Lice ◽  

Genes ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 857
Author(s):  
Gustavo Núñez-Acuña ◽  
Constanza Sáez-Vera ◽  
Valentina Valenzuela-Muñoz ◽  
Diego Valenzuela-Miranda ◽  
Gabriel Arriagada ◽  
...  

Caligus rogercresseyi, commonly known as sea louse, is an ectoparasite copepod that impacts the salmon aquaculture in Chile, causing losses of hundreds of million dollars per year. This pathogen is mainly controlled by immersion baths with delousing drugs, which can lead to resistant traits selection in lice populations. Bioassays are commonly used to assess louse drug sensitivity, but the current procedures may mask relevant molecular responses. This study aimed to discover novel coding genes and non-coding RNAs that could evidence drug sensitivity at the genomic level. Sea lice samples from populations with contrasting sensitivity to delousing drugs were collected. Bioassays using azamethiphos, cypermethrin, and deltamethrin drugs were conducted to evaluate the sensitivity and to collect samples for RNA-sequencing. Transcriptome sequencing was conducted on samples exposed to each drug to evaluate the presence of coding and non-coding RNAs associated with the response of these compounds. The results revealed specific transcriptome patterns in lice exposed to azamethiphos, deltamethrin, and cypermethrin drugs. Enrichment analyses of Gene Ontology terms showed specific biological processes and molecular functions associated with each delousing drug analyzed. Furthermore, novel long non-coding RNAs (lncRNAs) were identified in C. rogercresseyi and tightly linked to differentially expressed coding genes. A significant correlation between gene transcription patterns and phenotypic effects was found in lice collected from different salmon farms with contrasting drug treatment efficacies. The significant correlation among gene transcription patterns with the historical background of drug sensitivity suggests novel molecular mechanisms of pharmacological resistance in lice populations.


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