The development of the Norwegian wrasse fishery and the use of wrasses as cleaner fish in the salmon aquaculture industry

Norway leads the world aquaculture production of Atlantic salmon Salmo salar and farmed Norwegian Atlantic salmon is currently consumed around the globe. However, sea lice infestation is a major problem faced by the salmon aquaculture industry in Norway and elsewhere. The use of wild-caught cleaner fish, mainly wrasses, has been recommended over the other available methods as the most economical and environmentally friendly option to control sea lice infestation in salmon farming. Here, we review the development of the Norwegian wrasse fishery and the use of wrasses as cleaner fish. In this document, we address the sea lice problem and introduce the main wrasse species employed as cleaner fish, document the cleaning behaviour of wrasses, present the development of a new wrasse fishery associated with the salmon aquaculture industry, and finally, we identify the main challenges associated with the intensive use of wild-caught cleaner wrasses and provide some insight for future directions of the wrasse fishery and further development of aquaculture techniques to supply salmon facilities with domesticated cleaner fish.     

The competitiveness of the Chilean salmon aquaculture industry

Abstract

Commercial salmon and trout farming has emerged as a major industry in Chile during the 1990s. Salmon is not a native species to Chile, still excellent climatic conditions are provided for farming. Since 1992 Chile has been the second largest producer of farmed salmon and trout in the world after Norway. This report reviews the development of the Chilean salmonid industry from its early stages until today with respect to production patterns, legislation and main markets. A cost comparison between Chilean and Norwegian farmed salmon is also provided. Finally, the international competitiveness and future challenges of the Chilean salmonid farming industry are analysed.     

Aeromonas salmonicida infection in wrasse (Labridae), used as cleaner fish, on an Atlantic salmon, Salmo salar L., farm

Abstract. Typical Aeromonas salmonicida with similar biochemical characteristics to A. salmonicida from Atlantic salmon, was isolated from wrasse, Ctenolabrus rupestris (L.) and Centrolabrus exoletus (L.), stocked as cleaner fish with these salmon. Although no external clinical signs were apparent, localized bacterial microcolonies were observed in muscle, gills, intestine, kidney and myocardial tissue. Mortalities attributed to A. salmonicida comprised 55% (n = 32) of total mortalities. No carriers of A. salmonicida were found in wild wrasse following stress testing. Although salmon post-smolts died when challenged with 1 × 10⁵ ml^-1 of a virulent strain, there were no mortalities in challenged wrasse. An oral route of infection is suggested rather than water-borne transfer as wrasse browsed on salmon mortalities. Wrasse were treated for A. salmonicida infection by injection with antibiotic and were also vaccinated, and in the latter case, elevation of antibody levels was noted.     

The use of fish vaccines in the Chilean salmon industry 1999-2003

This study summarises the availability of fish vaccines in Chile in the period 1999–2003. Through a questionnaire survey, data on annual sales per product were obtained from seven pharmaceutical companies and data on the corresponding farmed salmonid population eligible for vaccination were obtained from Sernapesca. More than 20 vaccines for aquacultured fish were brought to the Chilean market during the study period. The estimated number of fish being immunized by immersion increased from 93 million to more than 200 million, whereas sales of fish vaccines for injection increased from 2,008 to 16,561 l, the latter amount corresponding to approx. 150 million doses. Estimated vaccine coverage in the susceptible species ranked from 37–84% for yersiniosis (ERM), from 51–17% for salmonid rickettsial septicaemia (SRS), and from 8–78% for infectious pancreatic necrosis (IPN). Vaccine coverage against bacterial kidney disease (BKD) remained below 5%.     

Correction to: Population genetic structure of lumpfish along the Norwegian coast: aquaculture implications

The original version of this article unfortunately contained an error where the figure caption for Figures 3 and 4 was mixed.     

Development of the use of wrasse to control sea lice on salmon farms in Ireland

Abstract. Developments in the use of wrasse as cleaner-fish in the control of sea lice ( Lepeophtheirus salmonis, Caligus elongatus ) in Ireland are reviewed. Corkwing, Symphodus melops , and goldsinny, Ctenolabrus rupestris , have controlled L. salmonis (<1 louse per salmon) on commercial farms. C. rupestris and rockcook, Centrolabrus exoletus , removed both adult and chalimus C. elongatus in aquarium trials. No egg-bearing lice were ever found on salmon in cages with wrasse, and numbers of mobile lice were maintained at <1 per salmon smolt.
Wrasse are fished using shrimp pots, optimally set for about 2 h. The fishery is seasonal and limited to >10cm wrasse occurring close to the farm, and distant from other farms. Localized reductions in the body length and numbers of wrasse have been detected in the second year of fishing in two areas respectively. Due to the fishery limitations and high fecundity of wrasse, impacts on wrasse populations should remain localized. All wrasse populations fished are screened for microbial diseases, and protozoan and metazoan parasites. Results are typical for wild marine fish but metazoan skin parasites are rare. No pathogens, including tests with an Aeromonas sp. found in wrasse, have been found to be transferable to salmon.
Wrasse are the only effective and continuous method of sea lice control legally available. Research efforts should be directed towards improving the availability, pathogen-free status, and husbandry of wrasse, to enable cleaner-fish technology to be more widely and efficiently utilized.     

工业化海水鱼类养殖现状与发展趋势

工业化养鱼是农业现代化发展的必然趋势,合乎国情的封闭式循环水养鱼是我国水产养殖的发展方向,配置科学合理的装备技术,通过水体颗粒物分离、控制病原菌数量、微生物净化、增氧等技术措施,使养殖环境达到生态清洁型,健康养殖,确保食品安全。     

A survey of wild marine fish identifies a potential origin of an outbreak of viral haemorrhagic septicaemia in wrasse,Labridae, used as cleaner fish on marine Atlantic salmon,Salmo salar L., farms

Viral haemorrhagic septicaemia virus (VHSV) was isolated from five species of wrasse (Labridae) used as biological controls for parasitic sea lice predominantly, Lepeophtheirus salmonis (Krøyer, 1837), on marine Atlantic salmon, Salmo salar L., farms in Shetland. As part of the epidemiological investigation, 1400 wild marine fish were caught and screened in pools of 10 for VHSV using virus isolation. Eleven pools (8%) were confirmed VHSV positive from: grey gurnard, Eutrigla gurnardus L.; Atlantic herring, Clupea harengus L.; Norway pout, Trisopterus esmarkii (Nilsson); plaice, Pleuronectes platessa L.; sprat, Sprattus sprattus L. and whiting, Merlangius merlangus L. The isolation of VHSV from grey gurnard is the first documented report in this species. Nucleic acid sequencing of the partial nucleocapsid (N) and glycoprotein (G) genes was carried out for viral characterization. Sequence analysis confirmed that all wild isolates were genotype III the same as the wrasse and there was a close genetic similarity between the isolates from wild fish and wrasse on the farms. Infection from these local wild marine fish is the most likely source of VHSV isolated from wrasse on the fish farms.     

水产养殖清洁生产的内涵与技术

清洁生产作为循环经济的主要生产方式适用于各生产性行业并有助于各生产行业的可持续发展。以陆上工厂化水产养殖为例，讨论了水产养殖业实施清洁生产的技术。     

Aquacultural development,institution building and research and development policy: Norwegian salmon and Arctic char farming as cases

Abstract

During the past 20 years, Norwegian salmon fanning has grown to achieve export sales of 7 billion Norwegian kroner (NOK). In the same period, Arctic char has been promoted as a lucrative farmed species. Paradoxically, despite the well‐documented advantages of Arctic char farming, this commercial activity has not prospered. Here I study the interaction between research and development and fish farming, and how this interaction affects industrial development within salmon farming and Arctic char farming, respectively. Effective communication between these systems presumes organization by some superior structure that controls the flow of industrial information to the research system, and prepares research results for industrial utility. The focus here is on: the perceptions of industrial actors of tasks for the research community; how researchers interpret and respond to these tasks; how the results are imparted to the fish‐farmers; and how the research results function in practice. I contend that adequate conditions for interaction between research and industrial activity exists for salmon farming, but not for Arctic char farming.     

Biomonitoring using tagged sentinel fish and acoustic telemetry in commercial salmon aquaculture: A feasibility study

We tested if it is technically feasible to monitor fish in real-time in full-scale commercial fish farms using acoustic telemetry. 31 Atlantic salmon were equipped with acoustic transmitter tags containing depth sensors. Tagged fish were monitored for three months in two industrial scale sea-cages containing 180000 and 150000 fish, respectively. Each cage was fitted with two prototype acoustic receiver units designed to collect, interpret and store the information transmitted by the acoustic transmitter tags. Ten in each cage were also equipped with Data Storage Tags (DSTs) containing depth sensors to record individual-based datasets for comparison with the acoustically transmitted datasets. After compensation for sample loss caused by expected acoustic interference between the transmitter tags, the resulting dataset revealed that the receiver units collected 90–95% of the signals in both cages. Acoustic communication conditions in the sea-cages were not strongly impaired by factors such as fish density and local noise. Further, the dataset from the acoustic transmitters had comparable resolution and quality to that produced by the DSTs. However, acoustic tags provide data in real time and enable farmers to respond to the received information with farm management measures, whereas archival tags such as DSTs need to be retrieved and downloaded and hence have no real-time applications. We conclude that acoustic telemetry is feasible as a method to monitor the depth of fish in real-time commercial aquaculture.     

On the drivers of cost changes in the Norwegian salmon aquaculture sector: a decomposition of a flexible cost function from 2001 to 2014

Abstract

Since 2005, Norwegian salmon farmers have experienced increasing unit costs, contrasting pre-2005 trends characterized by innovations, rapid productivity growth, and diminishing unit costs. This article investigates these cost changes using a panel of salmon producers. The drivers behind cost changes in the industry are identified for the period of 2001–2014 using a flexible cost function. In particular, it is explored how cost changes can be attributable to scale economies, negative productivity shocks, production expansion, and input prices. The results indicate that cost increases in the sector are affected by external factors out of the control of individual firms such as input prices and environmental conditions like sea lice.     

Assessing the feasibility of sponge aquaculture as a sustainable industry in The Bahamas

Sponge harvesting was a significant part of the Bahamian economy until the late 1930s when disease, hurricanes, and unsustainable harvesting practices reduced the viability of the sponge industry. Current international demands for natural products, increasing regional needs for economic diversification, and the historical foundation of sponging in The Bahamas makes sponge aquaculture a desirable candidate as a sustainable industry. To determine the feasibility of sponge aquaculture in The Bahamas, we deployed growout arrays between February 2006 and September 2009 at two sites off South Eleuthera to examine the survival and growth rates of grass sponge (Spongia tubulifera) and hardhead sponge (Spongia pertusa) cuttings. Complete skin regeneration occurred for both species by the second week following deployment. Following 43 months of growout, both grass and hardhead sponges showed significant positive growth, with cuttings of both species exhibiting faster growth trajectories at the more protected site (Site A) when compared with the site further from shore (Site B). The proportion of sponge cuttings lost during the course of the study was also considerably less for both species at Site A, as was the amount of required maintenance for the arrays. The initial deployment of larger sponge cuttings could help reduce the overall growout period, as would the selection of sites that offered more protection for growout. Based on these results, sponge aquaculture could prove to be a sustainable low-cost industry in The Bahamas; however, further research on site selection, regulations, and market acceptability remains to be done.     

祁连县养殖产业发展现状调查

祁连是一个以草地畜牧业为经济支柱的牧业县,畜牧养殖业在国民经济中占举足轻重的作用。发展畜牧养殖业业既是传统的民族经济,又是全县主导基础产业,发展藏羊、牦牛产业是提高我县农牧民收入的根本,对该县牲畜存栏情况、养殖藏羊、牦牛发展状况及存在的问题、进行了调查。     

Diet of demersal fish species in relation to aquaculture development in Scottish sea lochs

The diets of demersal fish, principally haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus) and several flatfish species, sampled from four Scottish sea lochs (Hourn, Kishorn, Duich and Nevis) which support aquaculture sites, were examined in order to determine whether the impact of aquaculture on benthic biodiversity would affect the diets of demersal fish. Loch Kishorn had the highest maximum planned aquaculture production, loch Nevis follows and lochs Hourn and Duich have the lowest planned production. Samples were collected from locations less than and more than 2000 m from fish farm cages. Fish close to the fish farm cages were on average of greater individual weight than those further away from fish farms. Haddock ate predominantly Malacostracan crustacea, Ophiurid echinoderms and Polychaete annelids; whiting ate predominantly Malacostracan crustacea and teleost fish and flatfish ate Malacostracan crustacea, Polychaete annelids and Ophiurid echinoderms. A small number of saithe sampled had eaten mainly fish farm pellets. Dietary variation in each species was analysed in relation to loch, proximity to aquaculture facilities and fish size. Diet of whiting varied with body size. Dietary differences were observed between the lochs and between sites close to and far from farms in two lochs although these differences cannot be specifically attributed to aquaculture development. Controlling for differences between individual lochs, proximity to aquaculture facilities did not consistently affect diet composition.     

石斑鱼类养殖技术体系的创建和石斑鱼养殖产业持续发展的思考

石斑鱼是驰名世界的名贵海产鱼类,是中国南方沿海广东、海南、福建、广西等海水养殖业的主要对象,经济价值巨大。中国石斑鱼类养殖兴起于20世纪80、90年代;进入21世纪,中山大学的研究团队围绕石斑鱼苗种繁育和养殖产业化的理论和技术进行了一系列研究,对其生殖调控、生长发育、营养需求、病害防治、种质分析、养殖技术和养殖模式等方面进行集成创新,建立苗种繁育和成鱼养殖各个环节的技术规范和管理措施,实现了石斑鱼苗种规模化繁育和自养自足,从而带动石斑鱼养殖产业发展到相当的规模。石斑鱼类养殖产业化持续健康发展的总体思路是：以建设资源高效利用、改善生态环境、产品优质安全的现代渔业基本内涵为目标,改革和提升传统养殖技术和养殖模式,转变产业发展方式,不断优化和提升产业链上的各项技术,包括：（1）优化苗种人工繁育技术,提高苗种成活率和苗种质量;（2）培育抗逆、抗病、优质、高产的优良品种;（3）配制高效、优质的人工配合饲料;（4）建立病害检测和防控新技术和研制主要疾病的特异性疫苗;（5）建立高效、低碳、节能的养殖技术,因地制宜地采用先进的养殖模式;（6）加强石斑鱼类的生物学基础研究以及生物科学和工程技术的交叉融合、协同发展,为石斑鱼养殖产业的技术创新和集约化与工程化奠定基础。     

A comprehensive survey on selective breeding programs and seed market in the European aquaculture fish industry

The use of selective breeding is still relatively limited in aquaculture species. Information on such activities is sparse, hindering an overall evaluation of their success. Here, we report on the results of an online survey of the major aquaculture breeding companies operating in Europe. Six main reared fish species were targeted. A total of 31 respondents contributed to the survey, representing 75 % of European breeding organizations. Family-based breeding schemes were predominant, but individual selection was more frequently applied in marine species. Artificial fertilization is the preferred means of reproduction; however, mass spawning is often used as a fallback method. The most frequently selected trait is growth performance, but the number of selected traits has been increasing over the years through the addition of traits such as disease resistance or product quality. The use of molecular tools is now common in all programs, mainly for pedigree traceability. An increasing number of programs use either genomic or marker-assisted selection. Results related to the seed production market confirmed that for Atlantic salmon there are a few dominant players at the European level, with 30–50 % market share. Only part of the European fish aquaculture industry today fully exploits selective breeding to the best advantage. A larger impact assessment still needs to be made by the remainder, particularly on the market share of fish seed (eggs, larvae or juveniles) and its consequences for hatchery stability.     

水产养殖中如何提高用药疗效

水产养殖中使用药物是避免不了的．药物是人类与水产动物病害作斗争的重要武器．也是增进水产动物机体健康．促进正常生长发育的重要手段。药物的使用不仅要对症．施用的方法也非常重要。实践中往往遇到疾病判断准确．用药效果不佳的现象．其中很大一部分因素就是使用中未能根据水产动物的生理特征、水质情况、药物形状、病程阶段进行合理施药造成的。本文根据给药途径的不同．结合水产动物的生理特异性对如何有效施药提出如下一些观点．     

A computer vision system to analyse the swimming behaviour of farmed fish in commercial aquaculture facilities: A case study using cage-held Atlantic salmon

Knowledge of fish behaviour plays an important role in aquaculture farm management. Video systems are the most common and cost-effective way of observing behaviours in commercial aquaculture operations. However long term observation is not feasible due to a limited ability to analyse footage manually. This paper describes preliminary findings obtained via computer vision software that was developed to automatically analyse fish movement and behaviours in aquaculture sea cages. Results show that the system is capable of detecting fish shapes in video recordings and from these shapes quantifying changes in swimming speed and direction continuously throughout the day. Also variations between days were detected and these may have been associated with the daily shift in the tidal cycle. The system has the potential to act as an alarm to farm operators, informing them about unusual fish behaviours on a continuous, real-time basis. It also has potential to assist in the evaluation of fish welfare.