This report is closed
Method development to estimate infection load in aquaculture
The aim of the pilot project was to create a DNA probe that binds to the genetic material of the fish-causing bacteria Flavobacterium psychrophilum and Aeromonas salmonicida, a subspecies of achromogenes, which can be detected using microscopy (FISH) and flow cytometry. One selective DNA probe for the bacterium F. psychrophilum was created with a combination of two and used with great success to screen for the bacterium using microbial and FISH technology. Specific DNA sensors could not be generated for A. Salmonicida, a subspecies of achromogenes, as its identification gene (16S rDNA) is too similar to other non-infectious Aeromans species. It will be necessary to develop new tentacles that are unique to A. Salmonicida, a subspecies of achromogenes. The flow cytometry is a very fast tool for detecting the binding of specific DNA sensors to microorganisms, which makes the device very suitable for detecting pathogenic bacteria in water. Quantitative analysis of bacteria with such technology is subject to various shortcomings, but it still gives a very good indication of the condition of the water in the fire so that the infection burden can be assessed. The results of this preliminary project show that it is possible to assess the infection burden in aquaculture quickly, but it is necessary to further develop and verify the methodology in real conditions in aquaculture. This was assumed at the beginning of this preliminary project and the participants have applied for a continuation grant to AVS based on the current results and the methodology will be tested under real conditions in charr farming.
The aim of this proof-of-concept study was the development and application of molecular probes for the fish pathogens Flavobacterium psychrophilum and Aeromonas salmonicida subsp. achromogenes, and their detection through Fluorescence In Situ Hybridization (FISH) and flow cytometry. A combination of two species-specific FISH probes was successfully used in combination with flow cytometry to identify and detected F. psychrophilum strains. It was not possible to find specific FISH probes for A. salmonicida subsp. achromogenes. The bacterium is too similar to other Aeromonas species in its 16S rRNA gene sequence and does not contain suitably unique regions that could have been used to develop a species-specific FISH probe. Flow cytometry offers a fast detection system for FISH probes, although technological limitations make reliable quantification difficult. The system is therefore best suited as a semi-quantitative early warning system for emerging fish pathogens in water samples from aquaculture tanks. The results of this preliminary project show that it is possible to estimate the infection load for certain pathogens in aquaculture rapidly but it is necessary to develop the methodology further and test it under real aquaculture conditions. The participants have applied to AVS for new funding based on these results; to develop our rapid methodology further, expand it to more pathogens and test it under real aquaculture conditions.
Testing different types of impregnations and its effect on bio fouling
The use of copper oxide in the treatment paint of cow bags is highly criticized and has been banned in many places due to its negative effects on the environment. Within the European Union, the use has been grayed out due to these negative effects of the substance on the environment, but it has been difficult to ban it as no substances have been found that repel sediments as well from the sacs as copper oxide. In the Norðurkví project, there has been a project where an attempt has been made to find a substance that could replace the copper oxide, but no permanent solution has been found. The results of this experiment are presented in this report.
Usage of copper oxide in treating net ‐ bags in aquaculture is a controversial and has been banned in many countries due to its negative environmental impact. Within the EU, use of copper oxide has been put on a gray list but not banned because no substitute treating material has been found which has the same effect in keeping algae away from the nets ‐ bags. The North Cage project has been looking into finding alternative solutions to copper oxide, and the conclusion of this research is drafted in this report.
Utilization of raw materials from the plant and animal kingdom in fish feed
Feed costs in aquaculture are generally around 50‐70% of operating costs and a large proportion of raw materials in feed are imported. The purpose of this report is to compile information on the possibility of utilizing domestic raw materials used in agriculture and fisheries for aquaculture feed. It is considered that the raw materials are generally used for aquaculture and the summary is not limited to individual species. It is possible to use by-products from the fisheries sector as feed in aquaculture, but by-products from the plant kingdom need to be treated in order to reduce / eliminate a high proportion of fiber and increase the protein content. By-products of the plant kingdom may be used as food for invertebrates, bacteria and fungi, thus producing a protein-rich product suitable for fish feed.
Feed cost in aquaculture is about 50‐70% of the total cost, and most of the feed is imported. The aim of this report is to gather information about utilizing by-products from agriculture and fishing industry as a feed in aquaculture. By-products from the fishing industry can be used as feed in aquaculture but it is necessary to lower the level of fiber and increase protein in by-products from agriculture. This can possibly be done by using the by-products as feed for invertebrates, bacteria and mushrooms and produce protein rich feed for aquaculture.
Affinity of benthic communities in Ísafjarðardjúpur
Knowledge of benthic life in the shallow waters off Iceland is low, both in terms of natural conditions and under stress from, for example, aquaculture. There is also a lack of knowledge about how benthic communities react to stress from aquaculture, but one study has tried to answer this regarding low stress. In order to understand which benthic community types exist under natural conditions and which are present in the case of pollution from pollution, the relationship between benthic life inside and outside the area must be examined. In this way, it is possible to understand which animal groups are predominant in similar situations. This study uses data on benthic life in Ísafjarðardjúpur, which is mostly due to fish farming in the fjords. A benthic study is also being carried out in fjords that may be suitable for aquaculture, but are still only under pressure from natural conditions. The project is part of a larger project "Icelandic fjords: The natural ecosystem of Ísfjarðardjúp and the limits of pollution" and is funded by the Fisheries Project Fund.
Knowledge about the benthic live in shallow waters around Iceland is poor, both regarding natural circumstances and when there is pressure from aquaculture. Knowledge is also poor about how benthic communities respond to pollution from aquaculture. This study shows the relationships between research stations with regards to kinship between found indicative species.
Fat tolerance of cod
The purpose of this study was to investigate the effect of fat content in feed on the growth and cleaning of cod of different sizes. Knowledge of the nutritional needs of fish is a necessary prerequisite for the preparation of feed for them. Two-size cod (120 g and 600 g) were fed (in triplicate) for 12 weeks on feed containing 10.0%, 13.5%, 21.2%, 24.5% and 27.7% fats in dry matter. Different fat content did not affect growth (SGR), body mass index (CF), fillet utilization, liver fat content or fillet fat content. In the smaller fish, the feed index (FCR) decreased with increased fat in the feed. The feed fat did not affect the fat content of offal without liver in the smaller fish (120g) but in 600 g fish the fat in the intestines increased with increased fat content of the feed. The fat content did not affect the proportion of gutted weight of the total weight in the 600 g fish, but in the smaller fish the proportion decreased with increased fat in the feed. Liver ratio (HSI) in 600g fish was not dependent on the fat content of the feed, but there was a positive correlation between feed fat and HSI in the 120 g fish. This means that the fat tolerance of cod in terms of liver ratio depends on the size of the fish.
Detailed knowledge of the nutritional requirements of fish is essential for feed formulation. The aim of this research was to investigate the effects of different lipid content in diets for Atlantic cod of different size. Cod of two size groups (initial weight 120 grams and 600 grams) were fed, in triplicate, for 12 weeks diets containing 10.0%, 13.5%, 21.2%, 24.5% and 27.7% lipid in dry matter. Different lipid content in the diet did not affect growth (SGR), condition factor (CF), fillet yield, lipid content in liver or lipid content in fillet. In the smaller fish, FCR was reduced with increased diet lipid. The lipid content in the diet did not affect the lipid content of intestines in the 120 grams fish but in the 600 grams fish there was a positive correlation between lipid content in diet and intestines. Dietary lipid did not affect gutted weight (calculated as the percentage of round weight) in the 600 grams fish but in the 120 grams fish, the percent gutted weight decreased with lipid content of the diet. The Heposomatic index (HSI) in the 600 gram fish was not affected by the lipid content of the diet but dietary lipid content significantly affected the HSI in the smaller fish. This indicates that the lipid tolerance of Atlantic cod, with respect to the effect on HSI, is size dependent.