<p>Aquaculture has become one of the fastest growing food industries in the world. Like many other industries, aquaculture, and especially fish farms may cause negative effects on the environment, such as eutrophication, which is recognised as a major threat to aquatic ecosystems. In this thesis such effects are studied in a number of lakes and Baltic coastal areas. The ecosystem scale in focus is an entire lake or defined coastal area in the size range 0.5-25 km². One important aim is to develop practically useful models that estimate the eutrophication effects as a function of fish farm load. Such models should be useful for the licensing authorities when giving permissions for fish farms.</p><p>It was concluded that fish farms might increase the surface water concentrations of total and dissolved phosphorus, total nitrogen and chlorophyll in lakes. Furthermore, traditional models overestimate the fish farm impact on lakes. Therefore, new models especially valid for fish farm emissions in lakes were developed.</p><p>A method to assess the sensitivity of coastal areas to an increased organic load from, e.g., fish farms was developed. Moreover, models to predict the enhanced phosphorus and chlorophyll-a concentrations and the decreased Secchi depth caused by fish farms were developed for coastal areas in the Åland archipelago. From extensive field studies in the Åland archipelago it was concluded that fish farms could cause increased total phosphorus concentrations, periphytic growth and phytoplankton biomass. However, those effects were generally only observed in small and semi-enclosed bays. Finally, the sediment quality beneath coastal fish farms was found to be a key parameter for the water quality, as well as for the recovery time after closure of fish farms.</p>

Aquaculture has become one of the fastest growing food industries in the world. Like many other industries, aquaculture, and especially fish farms may cause negative effects on the environment, such as eutrophication, which is recognised as a major threat to aquatic ecosystems. In this thesis such effects are studied in a number of lakes and Baltic coastal areas. The ecosystem scale in focus is an entire lake or defined coastal area in the size range 0.5-25 km2. One important aim is to develop practically useful models that estimate the eutrophication effects as a function of fish farm load. Such models should be useful for the licensing authorities when giving permissions for fish farms. It was concluded that fish farms might increase the surface water concentrations of total and dissolved phosphorus, total nitrogen and chlorophyll in lakes. Furthermore, traditional models overestimate the fish farm impact on lakes. Therefore, new models especially valid for fish farm emissions in lakes were developed. A method to assess the sensitivity of coastal areas to an increased organic load from, e.g., fish farms was developed. Moreover, models to predict the enhanced phosphorus and chlorophyll-a concentrations and the decreased Secchi depth caused by fish farms were developed for coastal areas in the Åland archipelago. From extensive field studies in the Åland archipelago it was concluded that fish farms could cause increased total phosphorus concentrations, periphytic growth and phytoplankton biomass. However, those effects were generally only observed in small and semi-enclosed bays. Finally, the sediment quality beneath coastal fish farms was found to be a key parameter for the water quality, as well as for the recovery time after closure of fish farms.

A study was made to evaluate how current measurementscould help to determine how particles from fish farms are dispersed. During sixweeks of the summer 2012, two different current measurements were conducted.One of them consisted of measurements each fifth minute at 5 m and 15 m atthree locations for 14-16 days each. The other consisted of profilemeasurements at each location at four times during the period of six weeks. Forthe current measurements two instruments (model RCM 9) were used. A two weekmeasurement can give enough data to make an evaluation of how the currents at alocation will transport litter from a fish farm. A longer probing time wouldhowever be desirable since the currents along the northern east coast of Swedenare mainly driven by factors that are changing during the year such as airpressure, temperature, precipitation etc. Water current measurements can be ofgreat help both when determining how particles from a fish farm is dispersedand also for governing authorities in the processes of both allowing new fishfarms and also when supervision of fish farms is needed.

The use of adaptive feeding systems to deliver feed remotely to Atlantic salmon (Salmo salar) cages has the potential to improve the localised environment through a reduction in particulate waste. This can be achieved through improved growth and lower Feed Conversion Ratio (FCR). The aim of this project was to assess whether adaptive feeding systems confer any environmental benefit at salmon farms through by comparing two fish farm sites, one that uses a Computer Aided System (CAS) adaptive feeding system (AKVAsmart UK limited, Inverness, Scotland) (Portavaide fish farm) and one using hand feeding (Rubha Stillaig). This investigation comprised of 3 elements: 1) a comparative assessment of the quantity and nutrient composition of particulate waste material emanating from the cages; 2) collection of benthic samples plus a video survey along transects at each site including a reference station, with an analysis of differences in benthic fauna, sediment grain size and sediment nutrient composition; and 3) comparison of the distribution of waste under each feeding regime using a GIS-based modelling approach. Particulate waste was collected via sediment traps. Uneaten feed was caught in only 3 out of 184 separate collections and thus no estimate of feed loss for each feeding system could be made. Samples were analyzed for total solids (TS), faecal solids (FS), faecal carbon (FC), faecal nitrogen (FN) content and faecal sedimentation rate (FSR). The highest deposition occurred under the cages and decreased with increased distance from the cage centre. Maximal deposition of TS at Portavadie was higher than at Rubha Stillaig when feed was included, although average TS, FS, Fe and FN per tonne of production did not significantly vary between sites. Carbon sedimentation rate was analyzed using regression analysis and a General Linear Model Factorial ANOVA on faecal waste only and showed no significant differences between sites and, therefore, no difference between feeding methods . There were no differences observed in the diversity and abundance of benthic species under the two feeding systems. By the end of the production period all stations out to 25m from the cage edge were dominated by Capitella capitata at both sites, this species proving a useful indicator of the impact of nutrient deposition. The analysis suggested that Heteromastus filiformis and Corophium sp. provided useful indicators of the onset of nutrient enrichment. Measurement of carbon and nitrogen levels and particle size in sediment showed no difference between sites. Variations between sites in species abundance and diversity and sediment carbon and nitrogen levels reflected the different sediment conditions prevalent at the start of the sampling period. Univariate and multivariate analysis showed there was no difference in species diversity and abundance between the sites as a result of using adaptive feeding systems. Horizontal cage movement, measured at up to 10m, reduced the predicted settlement under the cage by 23% and 11 % for feed and faecal distribution respectively. There was no significant difference in the predicted settlement of waste particulates under adaptive and hand feeding. The GIS model prediction of carbon flux (g C m-2 15-days-1) was validated for faecal settlement using sediment trap data where predictions agreed well with observations from Portavadie fish farm, with an accuracy of ± 53.1 % when all stations were included, improving to ± 27.6% when deposition under the cage was excluded. Overall, the approaches used did not identify specific differences between sites that used adaptive feeding and hand feeding methods. The growth period using the adaptive feeding system was approximately nine weeks shorter than under hand feeding, however, which could be used constructively to increase the fallowing period whilst maintaining current levels of production. This would benefit the localised benthos by increasing the time available for recovery before further production takes place and thus the CAS Adaptive Feeding System could be used as part of a broader sustainable farming strategy for fish culture.

<p>During the last decades, fish farming has been a rapidly increasing industry in many European and North American countries. Sweden has a large potential for aquaculture, but there is also a strong concern about the effects on the environment that an increased aquaculture production may cause. This thesis focuses on the eutrophication effects of fish farming in lakes and in coastal areas of the Baltic Sea.</p><p>Possible eutrophication effects related to marine fish farm emissions were found in small and semi-enclosed bays in the Åland archipelago of the Baltic Sea. Fish farming did not have any measurable large scale effect on TN in the Åland archipelago, but there were indications of a large scale effect on TP.</p><p>Nutrient concentrations and other eutrophication indicators in lakes with fish farms correlated well with the variations in farm load among the lakes and with distance from the fish farms within lakes. In a majority of the observed cases the effects on phosphorus concentrations were smaller than expected from the most commonly used models. Besides overestimating the effects, these old models described the variation between lakes adequately. It was therefore possible to construct farm specific steady state models based on the same model structures, that should be simple and accurate enough to be useful.</p><p>The observed effects on phosphorus concentrations tended to be higher in lakes where fish farms had been active for a long time, compared to lakes with new fish farms. Earlier investigations have shown that there is a considerable time lag in the response of changed phosphorus loads in many lakes. Empirical data and model simulations suggest that this is the case also for fish farm lakes.</p>

During the last decades, fish farming has been a rapidly increasing industry in many European and North American countries. Sweden has a large potential for aquaculture, but there is also a strong concern about the effects on the environment that an increased aquaculture production may cause. This thesis focuses on the eutrophication effects of fish farming in lakes and in coastal areas of the Baltic Sea. Possible eutrophication effects related to marine fish farm emissions were found in small and semi-enclosed bays in the Åland archipelago of the Baltic Sea. Fish farming did not have any measurable large scale effect on TN in the Åland archipelago, but there were indications of a large scale effect on TP. Nutrient concentrations and other eutrophication indicators in lakes with fish farms correlated well with the variations in farm load among the lakes and with distance from the fish farms within lakes. In a majority of the observed cases the effects on phosphorus concentrations were smaller than expected from the most commonly used models. Besides overestimating the effects, these old models described the variation between lakes adequately. It was therefore possible to construct farm specific steady state models based on the same model structures, that should be simple and accurate enough to be useful. The observed effects on phosphorus concentrations tended to be higher in lakes where fish farms had been active for a long time, compared to lakes with new fish farms. Earlier investigations have shown that there is a considerable time lag in the response of changed phosphorus loads in many lakes. Empirical data and model simulations suggest that this is the case also for fish farm lakes.

Several oomycete species of the genus Saprolegnia are recognized as devastating fish pathogens and are responsible for the loss of millions of fish annually for the aquaculture industry. Until recently, these pathogens were kept in check using malachite green; however, due to its toxicity, this chemical has now been banned from use. Saprolegnia parasitica is recognized as the major pathogen of aquaculture fish species. The industry is struggling to predict and control S. parasitica outbreaks in fish hatcheries and there is a need for new knowledge regarding the population genetic structure of this pathogen. Random amplified microsatellites were used to compare isolates of S. parasitica collected from a variety of hatchery locations during the period of November 2009 - August 2011, in order to determine the level of genetic variability and determine changes in genetic diversity over time. Allele frequencies of scored characters were graphically compared. Population genetic diversity was measured using Nei’s genetic distance, Shannon’s Information Index, number of polymorphic loci and phylogenetic trees. Due to the presence of Saprolegnia parasitica in the facilities tested, it appears to be ubiquitous in aquaculture facilities and treatment and prevention will be an ongoing concern in aquaculture management. Overall, genetic diversity of S. parasitica isolates was determined to be low with at least some sexual recombination occurring over time. There was a diversity of genotypes collected from the same hatchery on a single day, indicating there was not a single genotype present at a given time point. Genetic profiling, such as used here, could provide facility managers with a new approach to develop a series of best practices to control sporadic outbreaks of disease. Use of these genetic markers and close monitoring of S. parasitica genotypes will permit early detection and sanitation protocols. / Graduate / 2015-04-24 / 0476 / 0792 / 0369 / cren06@uvic.ca

Baigiamajame darbe nagrinėjama keturių Lietuvos pramoninės žuvininkystės ūkių į aplinką išleidžiama tarša (tiekiamo ir išleidžiamo vandens) pagal skendinčias medžiagas, BDS7, bendrą azotą ir bendrą fosforą ir pateikiamos rekomendacijos tvenkininių ūkių vandens kokybei gerinti. Darbo objektas: paviršinis vanduo. Darbo metodai – vertinama paviršinio vandens kokybė žuvininkystės ūkiuose aukščiau ir žemiau tvenkinių (tiekiamo ir išleidžiamo vandens). Darbo rezultatai. Išanalizavus daugiamečius žuvininkystės ūkių vandens kokybės tyrimų duomenis, gauti tokie rezultatai: 1. Skendinčiomis medžiagomis labiausiai užteršti: 1.1. UAB „Daugų žuvis“ tvenkiniai: (priimtuvas – Varėnės upė – 38,0 mg/l, 2009 m.) – žemiau tvenkinių; (priimtuvas – Žižmos upė – 37, 0 mg/l, 2007 m.) – žemiau tvenkinių. 1.2. AB „Išlaužo žuvis“ tvenkiniai: (priimtuvas – Jiesios upė – 47,0 mg/l, 2009 m.) – aukščiau tvenkinių; (priimtuvas – Jiesios upė – 54,0 mg/l, 2009 m.) – žemiau tvenkinių. Nežymiai skendinčių dalelių kiekį viršijo ir Šilavoto poskyrio tvenkiniai (priimtuvas – Jiesios upė – 27,0 mg/l, 2009 m.) – žemiau tvenkinių. 2. Nagrinėtuose žuvininkystės tvenkiniuose nei BDS7, nei bendras azotas, nei bendras fosforas neviršijo leistinų normatyvinių rodiklių. Apibendrinus gautus rezultatus peteikiamos sekančios rekomendacijos tvenkininių ūkių vandens kokybei gerinti: 1. Norint išvengti padidintų skendinčių dalelių koncentraciją pageidautina pagal galimybes didžiają paduodamo vandens dalį kaupti tam... [toliau žr. visą tekstą] / The thesis examines four Lithuanian industrial fish farms in releasing pollution (water supply and discharge) by TSS, BDS7, total nitrogen and total phosphorus and recommendations of farm ponds to improve water quality. Working properties: surface water Working methods - evaluating the quality of surface water in the farms above and below the pond (water supply and discharge). Results. Analysis of many fish farms on water quality survey data, the following results: First TSS most contaminated: 1.1. JSC "Daugų Pond: (Receiving - Varėnė River - 38.0 mg / l, 2009.) - below the dams; (Receiving - Zizmai River - 37, 0 mg / l, 2007.) - below the ponds. 1.2. AB Išlaužo Fish Pond: (Receiving - Jiesia River - 47.0 mg / l, 2009.) - above the pond; (Receiving - Jiesia River - 54.0 mg / l, 2009.) - below the ponds. Slightly higher than the amount of suspended solids and Šilavotas subdivision ponds (Receiving - Jiesia River - 27.0 mg / l, 2009.) - Below the ponds. Second INVESTIGATED fishponds than BDS7 than the total nitrogen or total phosphorus exceeded the permissible normative indicators. Summarizing the results peteikiamos next recommendation farm ponds to improve water quality: First to avoid increase of suspended particles concentration preferably by possibilities to a large flow of accumulating a dedicated, larger ponds or specially equipped stores and settle only part of the load of suspended particles continue growing pond filling. Second Extend pond filling period... [to full text]

abstract: Fish farming is a fast growing industry, which, although necessary to feed an ever growing worldwide population, has its share of negative environmental consequences, including the release of drugs and other waste into the ocean, the use of fish caught from the ocean to feed farm raised fish, and the escape of farm raised fish into natural bodies of water. However, the raising of certain types of fish, such as tilapia, seems to be an environmentally better proposition than raising other types of fish, such as salmon. This paper will explore the problems associated with fish farming, as well as offer a model, based on the literature, and interviews with fish farmers, to make small-scale fish farming both more environmentally, and more economically, sustainable. This paper culminates with a model for small-scale, specifically semi-subsistence, fish farmers. This model emphasizes education of the fish farmers, as well as educators learning from the fish farmers they interact with. The goal of this model is to help these fish farmers become both more environmentally and economically sustainable. / Dissertation/Thesis / M.S.Tech Technology 2011

Aquaculture facilities involve mooring a large amount of artificial structures in offshore areas, which are colonised by a wide group of marine organisms, forming characteristic fouling communities. Many studies have focused on determining what sessile organisms are able to settle on nets, ropes and buoys, owing to the specific problems they cause and their economic cost to the aquaculture industry. Although sessile fouling communities are well-studied from the point of view of controlling this community on aquaculture facilities, little is known about the epifaunal mobile species inhabiting these artificial structures. This thesis addresses the study of crustacean amphipods, which have been scarcely studied regarding their species composition and relation to the habitats created by the sessile species and despite being detected in high abundances. After the general introduction, which sets the study framework, Chapter 1 is a preliminary study on the composition of fouling assemblages on aquaculture facilities in the Mediterranean Sea, comparing them with others such as those in harbours or offshore structures. Therein, it is shown that fouling communities are made up of mainly bivalves, algae, hydroids and bryozoans and amphipods usually represent more than 80 % of motile fauna associated with these organisms. Moreover, amphipod assemblages are characterised by seven frequent and dominant species: Elasmopus rapax, Jassa marmorata, Jassa slatteryi, Ericthonius punctatus, Stenothoe tergestina, Caprella equilibra and Caprella dilatata. A quantitative study of amphipod densities is carried out in Chapter 2, where mean amphipod densities observed in fish farm fouling amounted to 176,000 ind.m-2 and reached maxima up to 1,000,000 ind.m-2. There, the role of the macro- and microhabitat in supporting such amphipod communities is explored. The effect of the modification of marine currents on pelagic communities due to the introduction of coastal infrastructures is analysed in Chapter 3. Therein, it was detected a retention effect on planktonic amphipods near such facilities, noticeable in the increased abundance of hyperiids and migrating amphipods from different benthic and floating habitats. The influence of fouling amphipods on other habitats is analysed in Chapters 4 and 5, it is shown that fish-farm fouling acts as a source population of amphipods dispersing towards both defaunated sediments in soft-bottoms and surrounding floating habitats. Finally, in the last chapter, based on the possibility of using wild fauna already growing in fish farms, the applicability of amphipods as an accessory culture is tested in an offshore integrated multi-trophic aquaculture (IMTA) system with finfish as main fed species. Throughout this thesis it has been shown that fish-farming activities affect the amphipod assemblage in several ways such as the establishment of high population densities or the intimate connectivity between different subpopulations. As a result, a new potential commercial application arises from the possibility of using them as biofilters of aquaculture wastes, within an off-coast integrated multitrophic aquaculture system, promoting a more sustainable development of aquaculture in the marine environment. / Las estructuras artificiales que conforman las instalaciones de acuicultura en mar abierto suelen ser colonizadas por multitud de organismos marinos, que forman comunidades de fouling características en estas estructuras. Muchos estudios se han centrado en la descripción de los organismos sésiles que se desarrollan sobre cabos, redes y boyas de las instalaciones de acuicultura, debido a los problemas que generan para el cultivo y los costes adicionales que significan para la industria derivados de su necesaria eliminación. Sin embargo, aunque las comunidades de fouling sésiles han sido bien estudiadas desde el punto de vista de su control en las instalaciones de acuicultura, poco se sabe sobre la epifauna que habita estas estructuras artificiales. Esta tesis se centra en el estudio de los crustáceos anfípodos, los cuales aún no han sido estudiados en cuanto a la composición de especies y a su relación con los hábitats creados por los organismos sésiles, a pesar de haber sido detectados en grandes abundancias en las instalaciones de acuicultura. Después de una introducción general, que establece el marco de estudio, el capítulo uno es un estudio preliminar sobre las comunidades de fouling de las instalaciones de acuicultura en el Mediterráneo, comparándolas con las desarrolladas en otras estructuras artificiales como puertos o plataformas petrolíferas. En este capítulo, se demuestra que las comunidades de fouling están compuestas principalmente por bivalvos, algas, hidrozoos y briozoos y que más de un 80% de la fauna asociada a estos organismos son anfípodos. Además el poblamiento se caracteriza por la presencia de siete especies de anfípodos que son frecuentes y abundantes: Elasmopus rapax, Jassa marmorata, Jassa slatteryi, Ericthonius punctatus, Stenothoe tergestina, Caprella equilibra y Caprella dilatata. Un estudio cuantitativo de las densidades de estos anfípodos se lleva a cabo en el capítulo 2, donde se encuentra que la densidad media es de 176.000 ind.m-2, con máximos de más de 1.000.000 ind.m-2. Allí se explora también el papel de los macro y microhábitats en mantener dichas poblaciones de anfípodos. El efecto de la modificación de corrientes sobre las comunidades plantónicas debida a la instalación de las piscifactorías se analiza en el capítulo 3. En él, se detectó una retención de los anfípodos planctónicos cerca de las instalaciones, evidenciada por el incremento en las abundancias de hipéridos y de anfípodos migradores desde diferentes hábitats bentónicos flotantes. La influencia de las grandes densidades de anfípodos del fouling sobre otros hábitats se estudia en los capítulos 4 y 5, donde se observó que el fouling actúa como fuente de anfípodos migradores, exportando individuos que colonizan tanto sedimentos defaunados en el fondo marino como otros hábitats flotantes cercanos. Finalmente, en el último capítulo se analiza la posibilidad de aprovechar la producción natural y la conectividad observadas a través del cultivo de anfípodos como parte de un sistema de acuicultura multitrófica integrada (AMTI) en mar abierto con peces como especie principal. A lo largo de esta tesis, se demuestra que la acuicultura influencia las poblaciones de anfípodos marinos, tanto en el establecimiento de grandes densidades de población como en la conectividad entre las diferentes subpoblaciones. Como resultado, surge una nueva aplicación comercial de la posibilidad de usar los anfípodos del fouling como biofiltros, reciclando los residuos de la acuicultura dentro de un sistema de acuicultura multitrófica, garantizando así un desarrollo más sostenible de la acuicultura en el medio marino.