Large-scale use of fish traps for monitoring sea trout (Salmo trutta) smolts and sea lice (Lepeophtheirus salmonis) infestations: efficiency and reliability

2015 ◽  
Vol 12 (1) ◽  
pp. 76-84 ◽  
Author(s):  
Pablo Arechavala-Lopez ◽  
Ingebrigt Uglem ◽  
Marius Berg ◽  
Pål Arne Bjørn ◽  
Bengt Finstad
Keyword(s):  
Salmo Trutta ◽  
Large Scale ◽  
Sea Lice ◽  
Lepeophtheirus Salmonis ◽  
Sea Trout ◽  
Fish Traps ◽  
Efficiency And Reliability

scholarly journals Sea lice (Lepeophtheirus salmonis and Caligus elongatus) infestation levels on sea trout (Salmo trutta L.) around the Irish Sea, an area without salmon aquaculture

2016 ◽  
Vol 73 (9) ◽  
pp. 2395-2407 ◽  
Author(s):  
Patrick Gargan ◽  
Egil Karlsbakk ◽  
John Coyne ◽  
Carys Davies ◽  
William Roche
Keyword(s):  
Salmo Trutta ◽  
Large Scale ◽  
Geographic Area ◽  
Sea Lice ◽  
Irish Sea ◽  
Lepeophtheirus Salmonis ◽  
Natural Background ◽  
Salmon Farming ◽  
Sea Trout ◽  
The Irish Sea

Abstract Sea trout are parasitized by two species of caligid copepod sea lice, Lepeophtheirus salmonis and Caligus elongatus. Generally, levels of lice infestation are low and few adverse effects on the host have been reported. However, with the advent of marine salmon farming since the 1980s, there have been many published accounts of L. salmonis sea lice epizootics on salmonids in aquaculture areas. Few large-scale studies are available on levels of sea lice infestation of sea trout in areas without salmon farms or before their development. Understanding natural background lice levels on sea trout is important to interpret lice levels on trout in aquaculture areas. The Celtic Sea Trout Project, an INTERREG IVA Ireland Wales EU funded project, examined the status, distribution, genetics, and ecology of sea trout around the Irish Sea and provided an opportunity to assess levels of lice on sea trout spatially and temporally in an area without marine salmon farming. The prevalence of L. salmonis remained constant over the 3 years (63–69%), whereas the prevalence of C. elongatus was lower (20–40%). The mean abundance of L. salmonis ranged from 3.6 to 3.8 and that of C. elongatus ranged from 0.6 to 4.3 (n = 850). There was a significant variation in L. salmonis abundance between marine areas. However, the relative stability in the prevalence and mean intensity of both lice species observed and the low mean abundances and very small proportion of juvenile life stages of L. salmonis reported here are similar to those reported from other studies in areas without salmon farming and likely represent natural background salmon lice levels on sea trout. This 3-year study, conducted over a wide geographic area, represents one of the largest studies of sea lice infestation patterns on sea trout in an area distant from finfish aquaculture influences.

scholarly journals Prevalence, abundance, and distribution of Lepeoptheirus salmonis (Krøyer, 1837) and Caligus elongatus (Nordmann, 1832) on wild sea trout Salmo trutta L.

2008 ◽  
Vol 65 (2) ◽  
pp. 171-173 ◽  
Author(s):  
K. Urquhart ◽  
C. C. Pert ◽  
R. Kilburn ◽  
R. J. Fryer ◽  
I. R. Bricknell
Keyword(s):  
Salmo Trutta ◽  
East Coast ◽  
Sea Lice ◽  
Lepeophtheirus Salmonis ◽  
Marine Science ◽  
Sea Trout ◽  
Anterior Dorsal ◽  
Abundance And Distribution

Abstract Urquhart, K., Pert, C. C., Kilburn, R., Fryer, R. J., and Bricknell, I. R. 2008. Prevalence, abundance, and distribution of Lepeoptheirus salmonis (Krøyer, 1837) and Caligus elongatus (Nordmann, 1832) on wild sea trout Salmo trutta L. – ICES Journal of Marine Science, 65: 171–173. Lepeophtheirus salmonis (Krøyer, 1837) and Caligus elongatus (Nordmann, 1832) were found on 100% and 90%, respectively, of 30 wild sea trout from the east coast of Scotland. Mean abundances of the same two sea lice were 7.8 and 7.7, respectively. The distribution of the two species of sea louse differed, however, with a greater proportion of L. salmonis in the posterior and anterior dorsal regions, and a greater proportion of C. elongatus in the caudal and posterior ventral regions.

Salmon lice infestations on sea trout predicts infestations on migrating salmon post-smolts

2017 ◽  
Vol 74 (9) ◽  
pp. 2354-2363 ◽  
Author(s):  
Knut Wiik Vollset ◽  
Elina Halttunen ◽  
Bengt Finstad ◽  
Ørjan Karlsen ◽  
Pål Arne Bjørn ◽  
...  
Keyword(s):  
Salmo Trutta ◽  
Negative Binomial ◽  
Predictive Ability ◽  
Current Method ◽  
Sea Lice ◽  
Lepeophtheirus Salmonis ◽  
Fish Farms ◽  
Sea Trout ◽  
Salmon Lice ◽  
Management Advice

Abstract Impacts of sea lice (Lepeophtheirus salmonis or Caligus spp.) on wild salmonids is currently one of the most important issues facing management of fish farms in salmon producing countries in the northern hemisphere. Surveillance of sea lice on wild Atlantic salmon (Salmo salar) is often hampered by the ability to catch enough migrating post-smolts. Therefore, sea lice abundance on anadromous trout (Salmo trutta) is often used to infer sea lice abundance on migrating salmon post-smolt. However, the assumption that there is a relationship between the abundance of lice on salmon and trout has never been tested. Here we use a dataset of sea lice on salmon post-smolt and sea trout that have been caught simultaneously in trawl hauls, to evaluate the correlation in abundance of sea lice between the two species using various statistical models. We demonstrate that trout generally has higher abundances of sea lice than salmon. Average lice per gram fish on sea trout (log transformed) predicted the abundance of lice on salmon best. Negative binomial models of lice counts were preferable to using trout lice counts as direct estimates of salmon lice abundance, and they had better predictive ability than logit models of high (vs. low) lice counts. Including the size of the salmon increased the predictive ability of the model, but these data are not generally available. The effect of salmon weight may have been a direct effect of body size, or an indirect effect of time spent in marine waters. Finally, we predict lower salmon lice counts on migrating salmon with our selected binomial model than with the current method of using trout lice counts as a direct estimator on salmon lice counts, and demonstrate that management advice would change considerably depending on the chosen method.

scholarly journals First Report of a Sea Louse, Lepeophtheirus salmonis, Infestation on Juvenile Pink Salmon, Oncorhynchus gorbuscha, in Nearshore Habitat

2003 ◽  
Vol 117 (4) ◽  
pp. 634 ◽  
Author(s):  
Alexandra B. Morton ◽  
Rob Williams
Keyword(s):  
Salmo Trutta ◽  
Pink Salmon ◽  
Sea Lice ◽  
Oncorhynchus Gorbuscha ◽  
Lepeophtheirus Salmonis ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Sea Trout ◽  
Close Proximity ◽  
Lethal Limit ◽  
Nearshore Habitat

High infestation rates of the Sea Louse (Lepeophtheirus salmonis) have been reported on juvenile salmonids in Europe since 1989; however, this species has not been reported on juvenile Pacific salmonids until now. Magnitude of Sea Lice infestation was examined in 2001 on juvenile Pink Salmon (Oncorhynchus gorbuscha) migrating through a British Columbia archipelago. On average, the 751 juvenile Pink Salmon sampled weighed 2.25 g (± 0.039 SE), were infected with 11.3 (± 0.41 SE) Sea Lice per fish and 6.1 (± 0.24SE) Sea Lice per gram host weight. Fully 75.0% of fish were infected at loads equivalent to or higher than the lethal limit reported for much larger Sea Trout (Salmo trutta) post-smolts. Abundance (Kruskal-Wallis statistic = 100.95, p<0.0001) and intensity (KW= 70.05, p<0.0001) of lice, and mean number of lice/g host weight (K-W= 112.23, p<0.0001) were significantly higher in juvenile Pink Salmon in close proximity to salmon farms, than in Pink Salmon distant from salmon farms.

Salinity and temperature effects on sea lice over-wintering on sea trout (Salmo trutta) in coastal areas of the Skagerrak

2002 ◽  
Vol 82 (5) ◽  
pp. 887-892 ◽  
Author(s):  
P.A. Heuch ◽  
J.A. Knutsen ◽  
H. Knutsen ◽  
T.A. Schram
Keyword(s):  
Temperature Effects ◽  
Salmo Trutta ◽  
Parasite Species ◽  
Salt Water ◽  
Infection Intensity ◽  
Sea Lice ◽  
Close Relative ◽  
Lepeophtheirus Salmonis ◽  
Low Salinity ◽  
Sea Trout

Both the salmon louse Lepeophtheirus salmonis and its close relative Caligus elongatus are ectoparasitic on Salmonidae in salt water in the northern hemisphere. In this study we monitored population dynamics of these parasites on anadromous brown trout, i.e. sea trout, on the Norwegian Skagerrak coast in the winters of 1998–1999 and 1999–2000. The low salinity was expected to reduce sea lice populations as lice do not tolerate sojourns of more than a few weeks, at most, in freshwater. Results confirmed the presence of both parasite species on estuarine sea trout in winter, and showed that the lice populations go through a bottleneck in this period. Prevalences of infection of both parasite species were very different in the two sampling periods, but fell below 10% in March in both winters. Median infection intensity was 1–2 fish−1. Salinity was statistically related to the presence of C. elongatus both winters, and to L. salmonis in 1999–2000. Temperature appeared to be less important for the abundance of lice.

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 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
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