scholarly journals Sea lice prevention strategies affect cleaner fish delousing efficacy in commercial Atlantic salmon sea cages

2020 ◽  
Vol 12 ◽  
pp. 67-80 ◽  
Author(s):  
K Gentry ◽  
S Bui ◽  
F Oppedal ◽  
T Dempster
Keyword(s):  
Atlantic Salmon ◽  
Sea Lice ◽  
Small Scale ◽  
Faroe Islands ◽  
Biological Control Agents ◽  
Prevention Strategies ◽  
Cleaner Fish ◽  
Salmon Lice ◽  
Multiple Structures ◽  
Production Period

Over the last 2 decades, cleaner fishes have been employed to remove external sea lice parasites from Atlantic salmon Salmo salar in sea cages. Norway, Scotland, Ireland, and the Faroe Islands combined now use ~60 million cleaner fish per year. While small-scale experiments demonstrate the efficacy of cleaner fishes, industrial-scale sea cages have multiple structures and conditions that create different environments, which may impact cleaner fish efficacy and welfare. Here, in commercial sea cages, we investigated if 4 different anti-lice strategies impacted the delousing efficacy, physical condition, and behaviour of cleaner fish (corkwing wrasse Symphodus melops). The strategies tested were: (1) cleaner fishes only; (2) cleaner fishes and functional feed; (3) cleaner fishes, functional feed, and deep lights and feeding; and (4) cleaner fishes, functional feed, deep lights and feeding, and lice skirts. Corkwing wrasse were sampled from 3 cage-level replicates of each anti-lice strategy 3 times over 2 mo. Lice levels on salmon were recorded every 3 to 4 wk. Only 11% of corkwing wrasse had salmon lice in their gut, with individual wrasse having up to 72 lice in their stomach. Wrasse in cages encircled by lice skirts consumed one-ninth as many lice as those in other anti-lice treatments and had less overall impact on the number of lice per salmon. Fin, skin, mouth and eye condition, K factor, and observed cleaning behaviours of corkwing wrasse were similar across all anti-lice strategies. Our results demonstrate that different in-cage anti-lice strategies altered the magnitude of lice consumption in corkwing wrasse at this site and for this production period. Moreover, while a small proportion of corkwing wrasse appear to target lice as prey, most individual corkwing wrasse were ineffective biological control agents in a full-scale farm setting.

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.

scholarly journals Survival and growth of sea-ranched Atlantic salmon, Salmo salar L., treated against sea lice before release

2006 ◽  
Vol 63 (7) ◽  
pp. 1317-1325 ◽  
Author(s):  
Ove T. Skilbrei ◽  
Vidar Wennevik
Keyword(s):  
Atlantic Salmon ◽  
Treated Group ◽  
Sea Lice ◽  
Control Fish ◽  
Release Date ◽  
The Third ◽  
Salmon Lice ◽  
Survival And Growth ◽  
The Difference ◽  
Adipose Fin

Abstract Cultured Atlantic salmon smolts were treated with Slice®, orally administered emamectin benzoate, before release in the Dale River, western Norway, to study the potential effects of sea lice during the early stages of their marine phase. In all, 10 470 treated and untreated (control) fish from ten family groups were adipose fin-clipped, coded-wire tagged, and released on three different dates in 2002 (11 May, 25 May, and 7 June), which coincided with the natural smolt run. The percentage of released smolts recaptured as one-sea-winter salmon in 2003 did not differ between the treated and untreated groups released on the two dates in May 2002, but the recapture rate of fish from the treated group released on 7 June 2002 was almost twice that of the controls. The weights of the recaptured one-sea-winter salmon tended to decline from the first to the third release date, and one-sea-winter salmon from the treated groups were approximately 15% heavier than the controls. The difference in recapture rate between the treated and untreated groups increased after inclusion of the two-sea-winter and three-sea-winter salmon recaptured in 2004 and 2005, respectively. We conclude that the infestation level of salmon lice changed from non-lethal to lethal levels during the period of the smolt migration in 2002 and that non-lethal infestation levels may adversely affect Atlantic salmon populations by reducing the growth rate of fish and, consequently, their size at spawning.

scholarly journals Vaccination with Ectoparasite Proteins Involved in Midgut Function and Blood Digestion Reduces Salmon Louse Infestations

Vaccines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 32 ◽  
Author(s):  
Marinela Contreras ◽  
Marius Karlsen ◽  
Margarita Villar ◽  
Rolf Olsen ◽  
Lisa Leknes ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Vaccine Development ◽  
Sea Lice ◽  
Salmon Louse ◽  
Blood Digestion ◽  
Protective Antigens ◽  
Salmon Lice ◽  
Tick Vaccine ◽  
European Aquaculture ◽  
Lice Infestations

Infestation with the salmon louse Lepeophtheirus salmonis (Copepoda, Caligidae) affects Atlantic salmon (Salmo salar L.) production in European aquaculture. Furthermore, high levels of salmon lice in farms significantly increase challenge pressure against wild salmon populations. Currently, available control methods for salmon louse have limitations, and vaccination appears as an attractive, environmentally sound strategy. In this study, we addressed one of the main limitations for vaccine development, the identification of candidate protective antigens. Based on recent advances in tick vaccine research, herein, we targeted the salmon louse midgut function and blood digestion for the identification of candidate target proteins for the control of ectoparasite infestations. The results of this translational approach resulted in the identification and subsequent evaluation of the new candidate protective antigens, putative Toll-like receptor 6 (P30), and potassium chloride, and amino acid transporter (P33). Vaccination with these antigens provided protection in Atlantic salmon by reducing adult female (P33) or chalimus II (P30) sea lice infestations. These results support the development of vaccines for the control of sea lice infestations.

Assessment of growth and sea lice infection levels in Atlantic salmon stocked in small-scale cages with lumpfish

Aquaculture ◽  
2014 ◽  
Vol 433 ◽  
pp. 137-142 ◽  
Author(s):  
Albert K. Imsland ◽  
Patrick Reynolds ◽  
Gerhard Eliassen ◽  
Thor Arne Hangstad ◽  
Ane Vigdisdatter Nytrø ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Sea Lice ◽  
Small Scale

scholarly journals Personality profiling may help select better cleaner fish for sea-lice control in salmon farming

2021 ◽  
Author(s):  
Benjamin Alexander Whittaker ◽  
Sofia Consuegra ◽  
Carlos Garcia de Leaniz
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Artificial Selection ◽  
Sea Lice ◽  
Cleaner Fish ◽  
Salmon Farming ◽  
Cyclopterus Lumpus ◽  
Atlantic Salmon Salmo Salar ◽  
Number Of Individuals ◽  
Practical Implications

Lumpfish (Cyclopterus lumpus) are increasingly being used as cleaner fish to control parasitic sea lice in salmon farming, but cleaning rates are very variable and not all individuals eat sea lice, which increases the risk of emaciation and has ethical and practical implications. Selecting good cleaners is a priority to make the industry more sustainable, but there is little information on what behaviours make cleaner fish effective under a commercial setting. We examined variation in lumpfish personalities according to the five factor personality model that takes into account differences in activity, anxiety (shelter use, thigmotaxis), aggression, sociality, and boldness (neophobia). We then quantified how variation in lumpfish personalities influenced interactions with naive Atlantic salmon (Salmo salar), without the confounding effects of variation in sea lice loads. Variation in activity, sociality, aggression and neophobia, but not in anxiety, was repeatable, which is consistent with a heritable basis. Neophilic, non aggressive lumpfish spent more time inspecting salmon than neophobic and aggressive individuals, but salmon fled in the presence of the most active and social individuals, suggesting there may be an optimal cleaner fish personality amenable to artificial selection. The personality screening protocols developed in this study could inform a more efficient use of cleaner fish in salmon farming and reduce the number of individuals required to control sea lice

scholarly journals A machine vision system for tracking population behavior of zooplankton in small-scale experiments: a case study on salmon lice (Lepeophtheirus salmonis Krøyer, 1838) copepodite population responses to different light stimuli

Biology Open ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. bio050724
Author(s):  
Bjarne Kvæstad ◽  
Trond Nordtug ◽  
Andreas Hagemann
Keyword(s):  
Machine Vision ◽  
Developmental Stages ◽  
Vision System ◽  
Behavioral Responses ◽  
Experimental System ◽  
Sea Lice ◽  
Small Scale ◽  
Lepeophtheirus Salmonis ◽  
Salmon Lice ◽  
Light Stimuli

ABSTRACTTo achieve efficient and preventive measures against salmon lice (Lepeophtheirus salmonis Krøyer, 1838) infestation, a better understanding of behavioral patterns of the planktonic life stages is key. To investigate light responses in L. salmonis copepodites, a non-intrusive experimental system was designed to measure behavioral responses in a 12.5-l volume using machine vision technology and methodology. The experimental system successfully tracked the collective movement patterns of the sea lice population during exposure to different light stimuli emitted from alternating zones in the system. This system could further be used to study behavioral responses to different physical cues of various developmental stages of sea lice or other zooplankton.

The poor potential of cunner, Tautogolabrus adspersus, to act as cleaner fish in removing sea lice (Caligus elongatus) from farmed salmon in eastern Canada

1995 ◽  
Vol 52 (S1) ◽  
pp. 175-177 ◽  
Author(s):  
B.M. MacKinnon
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Sea Lice ◽  
Tautogolabrus Adspersus ◽  
Eastern Canada ◽  
Cleaner Fish ◽  
Farmed Salmon ◽  
The Poor ◽  
Fouling Organisms ◽  
Farmed Atlantic Salmon

Cunner, Tautogolabrus adspersus, were found not to be good candidates for removal of sea lice, Caligus elongatus, from farmed Atlantic salmon (Salmo salar) during seapen trials conducted in Passamoquoddy Bay, N.B. In laboratory trials conducted in 30-gal (~136 L) glass tanks, using one cunner per infected salmon, a significant reduction in sea lice numbers was evident. In seapen trials using 30 cunner to 2000 Atlantic salmon, no significant reduction in sea lice numbers was evident after 12 weeks. Availability of fouling organisms on the seapen net may account, in part, for the lack of cleaning behaviour in these fish.

The Makrakomi Archaeological Landscapes Project. A preliminary report on investigations carried out in 2010–2012

2013 ◽  
Vol 6 ◽  
pp. 211-260 ◽  
Author(s):  
Maria-Foteini Papakonstantinou ◽  
Arto Penttinen ◽  
Gregory N. Tsokas ◽  
Panagiotis I. Tsourlos ◽  
Alexandros Stampolidis ◽  
...  
Keyword(s):  
Preliminary Report ◽  
Geophysical Survey ◽  
Small Scale ◽  
Hellenistic Period ◽  
Surface Survey ◽  
Multiple Structures ◽  
Recorded Data ◽  
Architectural Survey ◽  
The Hill ◽  
The Town

In this article we provide a preliminary report of the work carried out between 2010 and 2012 as part of the Makrakomi Archaeological Landscapes Project (MALP). The programme of research is carried out in co-operation between the Swedish Institute at Athens and the 14th Ephorate of Prehistoric and Classical Antiquities at Lamia. The interdisciplinary project started in the summer of 2010, when a pilot survey was conducted in and around the hill of Profitis Elias, in the modern municipality of Makrakomi, where extensive traces of ancient fortifications are still visible. Systematic investigations have been conducted since 2011 as part of a five-year plan of research involving surface survey, geophysical survey and small-scale archaeological excavation as well as geomorphological investigation. The primary aim of MALP is to examine the archaeology and geomorphology of the western Spercheios Valley, within the modern municipality of Makrakomi in order to achieve a better understanding of antiquity in the region, which has previously received scant scholarly attention. Through the archaeological surface survey and architectural survey in 2011 and 2012 we have been able to record traces of what can be termed as a nucleated and structured settlement in an area known locally as Asteria, which is formed by the projecting ridges to the east of Profitis Elias. The surface scatters recorded in this area suggest that the town was primarily occupied from the late 4th century BC and throughout the Hellenistic period. The geophysical survey conducted between 2011 and 2012 similarly recorded data which point to the presence of multiple structures according to a regular grid system. The excavation carried out in the central part of Asteria also uncovered remains of a single domestic structure (Building A) which seems to have been in use during the Late Classical and Hellenistic periods. The combined data acquired through the programme of research is thus highly encouraging, and has effectively demonstrated the importance of systematic archaeological research in this understudied area of Central Greece.

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