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Cleaner fish are increasingly being deployed in aquaculture as a means of biological control of parasitic sea lice, and consequently the farming of wrasse and lumpfish, the main cleaner fish species in current use in salmon farming, is now one of the fastest expanding aquaculture sectors, with over 40 hatcheries in Norway alone.Cleaner Fish Biology and Aquaculture Applications reviews and presents new knowledge on the biology of the utilised cleaner fish species, and provides protocols in cleaner fish rearing, deployment, health and welfare. The latest knowledge is presented on specialist technical areas such as cleaner fish nutrition, genetics, health, immunology and vaccinology, welfare, transport and fisheries. Specific chapters detail cleaner fish developments in the main salmon-producing countries.Contributions from over 60 leading researchers and producers give an exciting mix of information and debate. The book comprehensively addresses the questions of sustainability of cleaner fish use in aquaculture, bottlenecks to the optimum production of cleaner fish, and improvements and best practice in on-farm deployment methods, for optimum survival and enhanced welfare of cleaner fish.Some of the key features of this important book: Provides a comprehensive review of the latest globally available information on the use of cleaner fish under one cover. Highlights and addresses the main issues in the farming of cleaner fish and provides guidance on how to improve growth and survival. Identifies issues in the farm application of cleaner fish and provides details on how to address these issues. Written by a team of internationally recognised experts in cleaner fish biology, culture and deployment.Cleaner Fish Biology and Aquaculture Applications is an essential purchase for hatchery managers, salmonid producers, fish farm operatives, researchers, regulators, students and enthusiasts working with, and interested in, cleaner fish. Personnel within companies supplying equipment and services to the aquaculture industry, and libraries in all universities and research establishments where biological sciences and aquaculture are studied and taught should have copies of this landmark publication.

Ecological changes affect pathogen epidemiology and evolution and may trigger the emergence of novel diseases. Aquaculture radically alters the ecology of fish and their pathogens. Here we show an increase in the occurrence of the bacterial fish disease Flavobacterium columnare in salmon fingerlings at a fish farm in northern Finland over 23 years. We hypothesize that this emergence was owing to evolutionary changes in bacterial virulence. We base this argument on several observations. First, the emergence was associated with increased severity of symptoms. Second, F. columnare strains vary in virulence, with more lethal strains inducing more severe symptoms prior to death. Third, more virulent strains have greater infectivity, higher tissue-degrading capacity and higher growth rates. Fourth, pathogen strains co-occur, so that strains compete. Fifth, F. columnare can transmit efficiently from dead fish, and maintain infectivity in sterilized water for months, strongly reducing the fitness cost of host death likely experienced by the pathogen in nature. Moreover, this saprophytic infectiousness means that chemotherapy strongly select for strains that rapidly kill their hosts: dead fish remain infectious; treated fish do not. Finally, high stocking densities of homogeneous subsets of fish greatly enhance transmission opportunities. We suggest that fish farms provide an environment that promotes the circulation of more virulent strains of F. columnare. This effect is intensified by the recent increases in summer water temperature. More generally, we predict that intensive fish farming will lead to the evolution of more virulent pathogens.

Health Maintenance and Principal Microbial Diseases of Cultured Fishes, Third Edition  is a thoroughly revised and updated version of the classic text.Building on the wealth of information presented in the previous edition, this new edition offers a major revision of the valuable health maintenance section, with new pathogens added throughout.

This article explores the politics behind the promise of ‘blue growth’. Reframing it as a ‘blue fix’, we argue that the blue growth discourse facilitates new opportunities for capital accumulation, while claiming that this accumulation is compatible with social and ecological aims as well. The blue fix is made up of three underlying sub-fixes. First of all, the conservation fix quenches the social thirst for action in the face of climate change. Here we see how protecting marine areas can be an important part of mitigating climate change, but in practice, gains at the national level are overshadowed by the ongoing expansion of offshore drilling for oil and gas. Second, the protein fix satisfies the growing global demand for healthy food and nutrition through the expansion of capital-intensive large-scale aquaculture, while ignoring the negative socio-ecological impacts, which effectively squeeze small-scale capture fishing out, while industrial capture fishing remains well positioned to expand into as well as supply industrial aquaculture with fish feed from pelagic fish. And third, an energy fix offers a burst of wind energy and a splash of new deep-sea minerals without disturbing the familiar and persistent foundation of oil and gas. This dimension of the blue fix emphasizes the transition to wind and solar energy, but meanwhile the deep sea mining for minerals required by these new technologies launches us into unknown ecological territories with little understood consequences. The synergy of these three elements brought together in a reframing of ocean politics manifests as a balancing act to frame blue growth as ‘sustainable’ and in everyone’s interest, which we critically analyze and discuss in this article.

Anthropogenic deoxygenation of the Baltic Sea caused major declines in demersal and benthic habitat quality with consequent impacts on biodiversity and ecosystem services. Using Baltic cod otolith chemical proxies of hypoxia, salinity, and fish metabolic status and growth, we tracked changes from baseline conditions in the late Neolithic (4500 BP) and early twentieth century to the present, in order to understand how recent, accelerating climate change has affected this key species. Otolith hypoxia proxies (Mn:Mg) increased with expanding anoxic water volumes, but decreased with increasing salinity indexed by otolith Sr:Ca. Metabolic status proxied by otolith Mg:Ca and reconstructed growth were positively related to dissolved oxygen percent saturation, with particularly severe declines since 2010. This long-term record of otolith indicators provides further evidence of a profound state change in oxygen for the worse, in one of the world’s largest inland seas. Spreading hypoxia due to climate warming will likely impair fish populations globally and evidence can be tracked with otolith chemical biomarkers.

In view of the need to improve the development of family production enterprises, zootechnical and economic planning were conducted in a rural settlement in 0.78 ha of water depth for the rearing and marketing of juveniles of the tambatinga hybrid (♀ tambaqui Colossoma macropomum x ♂ pirapitinga Piaractus brachypomus) to verify its economic viability. For the zootechnical indicators, a 16-month production cycle was determined, with three juvenile production cycles and two fattening cycles. For the remaining fish that were not sold, the quantity of initial and final fish, stock biomass, average initial and final weight, apparent feed conversion, and mortality rate were determined. For economic planning, a total operating cost methodology was adopted to determine the costs per unit of production, gross revenue, gross margin, net profit, and profitability index. The production of juveniles of many sizes is economically viable for family farming, showing attractive profitability indicators even under adverse zootechnical conditions. This study demonstrated the effectiveness of zootechnical and economic planning on a property that can optimize production and use of the area, as well as showing producers how rewarding it is to farm fish.

Efforts are on the way on the Swedish West Coast to develop the capacity for cultivation of marine resources, notably of kelps. Given that this is a region of great natural and national heritage, public opposition to marine developments has been identified as a possible risk factor. This survey thus sought to shed light on awareness levels, perceptions of different types of aquaculture and on reactions to a scenario depicting future aquaculture developments on the West Coast. When asked about their general opinions of aquaculture, respondents tended to be favourable though a majority chose neutral responses. On the whole, respondents were favourable to the depicted scenario. Finally, it was found that the high-awareness group tended to be more supportive than the low or medium-awareness groups, hinting at the benefits of increasing awareness to reduce public aversion and to support a sustainable development of aquaculture on the Swedish West Coast.

This study is the first contribution to monitoring the rearing of common meagre Argyrosomus regius in floating cages anchored in Dakhla Bay, southern Morocco. The aquaculture potential of common meagre in Dakhla Bay was evaluated by zootechnical monitoring of two production cycles. The first batch consisted of 20,000 fingerlings of 4.5 ± 0.13 g in mean initial weight and 6±0.19 cm in fork length, and was caught on 26 August 2019 under a condition factor of about 2.08 ± 0.35. The second batch consisted of 30,000 individuals of 3 ± 0.11 g in average initial weight and 6±0.26 cm in average initial length, and was caught on 4 June 2020 under a condition factor of about 1.39 ± 0.21. During the first experiment, which lasted 16 months, a high growth potential of common meagre was observed. The fish reached an average weight of 1265 ± 69.2 g and an average length of 48±4.32 cm with a specific growth rate (SGR) of 0.58 ± 0.11% day-1 and a daily growth index DGI of 2.45 ± 0.91 g ind-1 day-1. The feed conversion ratio was 1.18 (FER = 0.84), final density was 36.94 kg m-3 and condition factor (k) recorded a mean value of 2.18±0.39 throughout the cycle. The survival rate at the first harvest was 89.86%. After 18 months of rearing, the fish of the second cycle reached a weight of 1285±69.2 g and a size of 47 ± 5.36 cm, with an SGR of 0.49 ± 0.12 % day-1 and a DGI of 2.34 ± 1.35 g ind-1 day-1, an FCR of 1.21 (FER =0.83), the final density of 28.43 kg m-3 and a condition factor of 1.35 ± 0.32. The survival rate was 92.19%. However, the results of the statistical analysis showed that there was no significant difference between the two production cycles (P > 0.05). These results confirm that common meagre is a very promising species for the diversification of aquaculture in Dakhla Bay and throughout Morocco.

Tilapia is a species with great growth potential. Its production comes from a semi-intensive system, such as earthen ponds (EP). Recently, biofloc technology (BFT) appears as an option to intensify fish production. The objective of this work was to compare the organosomatic indices, biochemical parameters, and chemical composition of tilapia reared in EP and BFT. Fish were grown for 150 days, with an initial weight of ≅ 2 g and a final weight of ≅ 780 g. Thereafter, tissues and organs were collected to determine organosomatic indices and analyze biochemical parameters, fatty acid, and proximate composition. The carcass yield was higher for tilapia reared in EP than BFT. The production system did not affect the fish fillet yield. The other organosomatic parameters were higher for tilapia reared in BFT. Tilapia reared in EP showed higher content of crude protein and lipids in the fillet. In both production systems, there was no difference in the body lipid profile. Fish in BFT showed a higher concentration of glucose and ammonia in the muscle and amino acids in the liver. Fish reared in EP showed a higher concentration of lactate in the liver compared to those in BFT. In conclusion, the production system alters the metabolism of fish. The biofloc has a considerable amount of fatty acids, which can be considered in the formulation of diets for tilapia in this system.

This study aimed to detect pesticides in the muscle tissue of farmed tambaqui (Colossoma macropomum), in relation to good management practices (GMP) and prophylaxis and biosecurity measures. There were 54 fish farms randomly selected from the 138 found in the Microregion of Zona da Mata, RO - Brazil, for visits and collection of epidemiological data. There were extracted 24 muscle fragments were extracted from dorsolateral portion of the tail of five specimens tambaqui per fish farming. The methods of detection and quantification of pesticide residues were modified QuEChERS and GC-MS/MS. Most fish farms are small businesses and their production areas are smaller than a rural module. These ventures are an income alternative for rural producers, this information is confirmed in percentage of 88.89% (48/54) of the rural properties visited have livestock and agriculture as their main productive activity. Water monitoring was carried out in 70.37% of fish farms. However, with frequency of two water analyzes per year. Preventive and prophylactic measures taken were performed in 30% (17/54). In addition, 7% (4/54) of fish farmers reported using sodium chloride and/or using formalin as a secondary preventive measure. It is also important to mention that there was a report of administration of potassium permanganate in a fish farm, 2% (1/54). There were 12.49% (3/54) positive for at least one pesticide. The chemical compounds found Azosxystrobin (

Journal Article

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