scholarly journals The planktonic stages of the salmon louse (Lepeophtheirus salmonis) are tolerant of end-of-century pCO2 concentrations

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7810 ◽  
Author(s):  
Cameron R.S. Thompson ◽  
David M. Fields ◽  
Reidun M. Bjelland ◽  
Vera B.S. Chan ◽  
Caroline M.F. Durif ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Fatty Acid Content ◽  
Lepeophtheirus Salmonis ◽  
Free Living ◽  
Salmon Aquaculture ◽  
Salmon Lice ◽  
Host Parasite ◽  
Lecithotrophic Development ◽  
High Treatment ◽  
Marine Parasite

The copepod Lepeophtheirus salmonis is an obligate ectoparasite of salmonids. Salmon lice are major pests in salmon aquaculture and due to its economic impact Lepeophtheirus salmonis is one of the most well studied species of marine parasite. However, there is limited understanding of how increased concentration of pCO2 associated with ocean acidification will impact host-parasite relationships. We investigated the effects of increased pCO2 on growth and metabolic rates in the planktonic stages, rearing L. salmonis from eggs to 12 days post hatch copepodids under three treatment levels: Control (416 µatm), Mid (747 µatm), and High (942 µatm). The pCO2 treatment had a significant effect on oxygen consumption rate with the High treatment animals exhibiting the greatest respiration. The treatments did not have a significant effect on the other biological endpoints measured (carbon, nitrogen, lipid volume, and fatty acid content). The results indicate that L. salmonis have mechanisms to compensate for increased concentration of pCO2and that populations will be tolerant of projected future ocean acidification scenarios. The work reported here also describes catabolism during the lecithotrophic development of L. salmonis, information that is not currently available to parameterize models of dispersal and viability of the planktonic free-living stages.

scholarly journals Salmon lice evasion, susceptibility, retention, and development differ amongst host salmonid species

2017 ◽  
Vol 75 (3) ◽  
pp. 1071-1079 ◽  
Author(s):  
Samantha Bui ◽  
Elina Halttunen ◽  
Agnes M Mohn ◽  
Tone Vågseth ◽  
Frode Oppedal
Keyword(s):  
Atlantic Salmon ◽  
Chinook Salmon ◽  
Salmo Trutta ◽  
Parasite Development ◽  
Lepeophtheirus Salmonis ◽  
Sea Trout ◽  
Salmon Lice ◽  
Salmonid Species ◽  
Host Parasite ◽  
Temporal Overlap

Abstract With different ecological characteristics amongst salmonid species, their response to parasitic infestation is likely to vary according to their spatial and temporal overlap with the parasite. This study investigated the host–parasite interactions amongst three species of salmonids and the ectoparasitic salmon louse, Lepeophtheirus salmonis. To determine any variation in infestation parameters amongst salmonids, single population groups of Atlantic salmon (Salmo salar), chinook salmon (Onchorhynchus tshawytscha), and previously-infested and naïve sea trout (Salmo trutta) were exposed to a controlled infestation challenge. We found that chinook salmon and both sea trout groups were more susceptible to acquiring lice than Atlantic salmon. Behavioural responses during infestation were more pronounced in Atlantic and chinook salmon. Parasite development was similar in lice attached to Atlantic salmon and sea trout, but hindered on chinook salmon. At 16 days post-infestation, chinook salmon had reduced lice loads to the same level as Atlantic salmon, whilst sea trout retained their lice. These results demonstrate differences in interactions with L. salmonis amongst these species, and highlight the vulnerability of sea trout to infestation.

scholarly journals Principles and Methods of Counteracting Harmful Salmon–Arthropod Interactions in Salmon Farming: Addressing Possibilities, Limitations, and Future Options

2021 ◽  
Vol 8 ◽  
Author(s):  
Prashanna Guragain ◽  
Max Tkachov ◽  
Anna Solvang Båtnes ◽  
Yngvar Olsen ◽  
Per Winge ◽  
...  
Keyword(s):  
Pest Management ◽  
Lepeophtheirus Salmonis ◽  
Pesticide Use ◽  
Fish Health ◽  
Negative Effects ◽  
Salmon Aquaculture ◽  
Salmon Lice ◽  
High Concentrations ◽  
Physical Treatments ◽  
Very High

The arthropod salmon louse (Lepeophtheirus salmonis) is a major threat to Atlantic salmon aquaculture and wild salmonids. Essentially like in monoculture, very high concentrations of susceptible hosts may result in high reproduction and severe production of waves of pests. Pest management is crucial both for fish health and protection of wild fish populations from aquaculture influence. Various methods have been utilized to control salmon lice infestations, such as pesticide use, physical treatments, construction modifications, fallowing, breeding, vaccination, and biological control. Most of the methods are partially successful, but none completely fulfills the necessary pest control strategy. Like in agriculture, lice/pest management is an arms race, but the marine environment makes it even more difficult to precisely hit the target pest and avoid unintended negative effects on general wildlife. In this study, we provide an overview of the methods and principles of salmon lice management and address current possibilities and limitations. We also highlight the potential of emerging strategies and enabling technologies, like genome editing, RNA interference, and machine learning, in arthropod management in aquaculture.

scholarly journals Effects of salmon lice Lepeophtheirus salmonis on wild sea trout Salmo trutta—a literature review

2015 ◽  
Vol 7 (2) ◽  
pp. 91-113 ◽  
Author(s):  
EB Thorstad ◽  
CD Todd ◽  
I Uglem ◽  
PA Bjørn ◽  
PG Gargan ◽  
...  
Keyword(s):  
Literature Review ◽  
Salmo Trutta ◽  
Lepeophtheirus Salmonis ◽  
Sea Trout ◽  
Salmon Lice

scholarly journals Effect of elevated CO<sub>2</sub> on the dynamics of particle attached and free living bacterioplankton communities in an Arctic fjord

2012 ◽  
Vol 9 (8) ◽  
pp. 10725-10755 ◽  
Author(s):  
M. Sperling ◽  
J. Piontek ◽  
G. Gerdts ◽  
A. Wichels ◽  
H. Schunck ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Atmospheric Carbon Dioxide ◽  
Intergenic Spacer ◽  
Extracellular Enzyme ◽  
The Arctic ◽  
Organic Substrates ◽  
Viral Lysis ◽  
Free Living ◽  
High Co2 ◽  
Carbon Dioxide Co2

Abstract. The increase in atmospheric carbon dioxide (CO2) results in acidification of the oceans, expected to lead to the fastest drop in ocean pH in the last 300 million years, if anthropogenic emissions are continued at present rate. Due to higher solubility of gases in cold waters and increased exposure to the atmosphere by decreasing ice cover, the Arctic Ocean will be among the areas most strongly affected by ocean acidification. Yet, the response of the plankton community of high latitudes to ocean acidification has not been studied so far. This work is part of the Arctic campaign of the European Project on Ocean Acidification (EPOCA) in 2010, employing 9 in situ mesocosms of about 45 000 l each to simulate ocean acidification in Kongsfjorden, Svalbard (78°56.2' N 11°53.6' E). In the present study, we investigated effects of elevated CO2 on the composition and richness of particle attached (PA; >3 μm) and free living (FL; <3 μm >0.2 μm) bacterial communities by Automated Ribosomal Intergenic Spacer Analysis (ARISA) in 6 of the mesocosms and the surrounding fjord, ranging from 185 to 1050 initial μatm pCO2. ARISA was able to resolve about 20–30 bacterial band-classes per sample and allowed for a detailed investigation of the explicit richness. Both, the PA and the FL bacterioplankton community exhibited a strong temporal development, which was driven mainly by temperature and phytoplankton development. In response to the breakdown of a picophytoplankton bloom (phase 3 of the experiment), number of ARISA-band classes in the PA-community were reduced at low and medium CO2 (∼180–600 μatm) by about 25%, while it was more or less stable at high CO2 (∼ 650–800 μatm). We hypothesise that enhanced viral lysis and enhanced availability of organic substrates at high CO2 resulted in a more diverse PA-bacterial community in the post-bloom phase. Despite lower cell numbers and extracellular enzyme activities in the post-bloom phase, bacterial protein production was enhanced in high CO2-treatments, suggesting a positive effect of community richness on this function and on carbon cycling by bacteria.

Thermal delousing in anaesthetised small Atlantic salmon (Salmo salar) post-smolts: A case study showing the viability of anaesthesia prior to delousing for improved welfare during treatment for salmon lice

2021 ◽  
Vol 30 (2) ◽  
pp. 117-120
Author(s):  
O Folkedal ◽  
SO Utskot ◽  
J Nilsson
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Experimental Research ◽  
Acute Stress ◽  
Small Scale ◽  
Lepeophtheirus Salmonis ◽  
Salmon Lice ◽  
Sequence Of Events ◽  
Present Case Study

Delousing treatment for salmon sea lice (Lepeophtheirus salmonis) is considered a significant welfare concern in farming of Atlantic salmon ( Salmo salar), where both industry and legislative bodies prompt for better methods. Currently, the most common method is thermal delousing, where fish are crowded, pumped into a vessel and exposed to ∼28–34°C for ∼30 s. Physical collisions occurring as a result of a loss of behavioural control lead to acute stress. Crowding triggers vigorous escape behaviour as salmon respond not only to treatment but also to being channeled to and from the treatment zone. A sequence of events considered to cause mortality and poor welfare. The present case study was motivated by an urgent need for delousing in groups of small salmon post-smolts in experimental research. For this purpose, a simple, small-scale system for thermal delousing was constructed, including anaesthesia to alleviate behavioural responses. The anaesthetised fish showed little behavioural response to thermal treatment, strong appetite within hours, and negligible mortality. The described method is regarded as a welfare-friendly alternative to industrial delousing in smaller fish groups, for example, in experimental research. We would encourage detailed research aimed towards gaining a deeper under-standing of the welfare effects of anaesthesia prior to treatment for delousing.

The Ecology of Juvenile Salmon in the Northeast Pacific Ocean: Regional Comparisons

2007 ◽  
Keyword(s):  
Coastal Waters ◽  
Pacific Salmon ◽  
Size Class ◽  
Small Fish ◽  
Lepeophtheirus Salmonis ◽  
Northeast Pacific ◽  
Salmon Lice ◽  
Regional Comparisons ◽  
Northeast Pacific Ocean ◽  
Over Time

Abstract.—We report patterns of infestation with motile salmon lice, <em>Lepeophtheirus salmonis</em>, on Pacific salmon collected with a surface trawl in coastal waters of Oregon, Washington, British Columbia, and Alaska during 2002 and 2003. Salmon lice were observed on all salmon species examined and in all areas surveyed. The prevalence and abundance of lice infestation varied significantly among species, size-classes, seasons, regions, and years, with larger salmon being consistently more heavily infested than small salmon. The number of lice infesting the small size-class (100–400 mm) of salmon rarely exceeded 5 lice per fish with a mean abundance generally below 0.2 lice per fish. Lice prevalence and, to a lesser extent, lice abundance increased over time in small fish, with lower values during spring and higher values in the following winter, and continued to increase in larger and older fish. There were no apparent effects of water temperature on lice infestation in Pacific salmon. This study suggested that salmon infested with lice remained in coastal waters throughout the year. We suggest that lice on salmon that overwinter in coastal waters will contribute to a pool of infective copepodids in these habitats.

scholarly journals Ultrastructure of the cuticle of the chalimus larva of the salmon louse Lepeophtheirus salmonis (Krøyer, 1837) (Copepoda: Caligidae)

2000 ◽  
Vol 69 (1-2) ◽  
pp. 39-49 ◽  
Author(s):  
J.E. Bron ◽  
A.P. Shinn ◽  
C. Sommerville
Keyword(s):  
Lepeophtheirus Salmonis ◽  
Free Living ◽  
Salmon Louse ◽  
Parasitic Species

The cuticle of the chalimus II stage of Lepeophtheirus salmonis (Copepoda: Caligidae) comprised a four-layered epicuticle with a pronounced fuzzy coat which was separated from the outer and inner procuticles by a layer of transitional procuticle. The cuticle is underlain by a single-layered epidermis which overlies integumental glands and chromatophores. The structure of this cuticle is very similar to that described for free-living copepods and does not display the modifications associated with more highly transformed parasitic species.

The development of salmon lice (Lepeophtheirus salmonis) on artificially infected post smolts of sea trout (Salmo trutta)

1998 ◽  
Vol 76 (5) ◽  
pp. 970-977 ◽  
Author(s):  
Pål Arne Bjørn ◽  
Bengt Finstad
Keyword(s):  
Salmo Trutta ◽  
Adult Stage ◽  
Infection Intensity ◽  
Developmental Rate ◽  
Infected Fish ◽  
Random Pattern ◽  
Lepeophtheirus Salmonis ◽  
Skin Damage ◽  
Sea Trout ◽  
Salmon Lice

The developmental rate, distribution on the host, and pathogenicity (skin damage) of salmon lice (Lepeophtheirus salmonis) were tested on artificially infected sea trout (Salmo trutta) post smolts. Male lice developed faster than females, taking approximately 29 and 38 days, respectively, to reach the adult stage at 10°C. During this time, infection intensity decreased. Less than 40% of the lice reached the adult stage, and their distribution changed from overdispersed towards a more random pattern. The chalimus larvae of the lice exhibited a preference for the gills and fins, especially the dorsal fin, and caused only minor skin damage. When the preadult and adult stages appeared, skin damage became severe, especially on the preferred head and dorsal areas, causing mortality of the most heavily infected fish.

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