Tag: Cod

Reports

Photoperiod and genetics of growth and maturity in cod (Gadus morhua)

Published:

01/04/2010

Authors:

Guðmundur Óli Hreggviðsson, Ólafur H. Friðjónsson, Þorleifur Ágústsson, Sigríður Hjörleifsdóttir, Kjell Hellman, Filipe Figueiredo, Helgi Thorarensen

Supported by:

Technology Development Fund, The Icelandic Center for Research

Contact

Guðmundur Óli Hreggviðsson

Strategic Scientist

gudmundo@matis.is

Photoperiod and genetics of growth and maturity in cod (Gadus morhua)

One of the main problems of cod farming is premature puberty, which results in slower growth and a much longer rearing period. Preliminary studies carried out in pots on land indicated that a new type of light, the so-called CC light, which emits light of one wavelength (green light) had a much greater effect on growth (up to 60% growth increase) and timing of puberty than conventional halogen light. This study examined the role of genotype and expression of certain key genes in response to light cycles, the determination of premature puberty and the association with increased cod growth in aquaculture. It was investigated whether, body size, weight and premature puberty were familial traits. At the end of a six-month indoor spawning season with two types of lighting, one with white halogen light and the other with continuous CC light, the cod was warlike in sea cages. In the sea cages he was also subjected to different light cycle treatments on the one hand with continuous CC light and on the other hand with natural light. After two years of sea farming, the fish were slaughtered, the phenotype of growth and sexual maturity was determined and it was divided into sibling groups, a total of approx. 2000 fish from each treatment separately. It was found that CCL light had a clear effect on delaying puberty and was much more noticeable in hens. The gonads developed much more slowly and not at all to the full compared to cod raised during the natural light cycle at the same time. There was also some variation between sibling groups in the effect of light on the development of gonads. On the other hand, this delay in puberty did not lead to such a sensitive growth rate. The familial similarity of growth patterns was also examined and a clear difference in mean weight was found between sibling groups. Responses to CCL treatment, however, were very divergent and appeared to vary between sibling groups. CCL treatment appeared to increase growth rate in some groups but slow growth rate in others. This could vary by gender. It was also investigated whether pretreatment of broths with CCL light during the coastal spawning season made the cod more sensitive to the effects of CCL light at sea level. That did not turn out to be the case. Certain key genes in growth and puberty control were isolated, along with some or all of their infiltrates. These were growth hormone (GH) genes, growth hormone receptors, growth hormone releasing factor (GHRF) receptors and insulin-like growth factor receptor2 (IGF2) receptors. In the sequences of three of these genes, GH, GHR and IGF2, variable mutations were found and a method for genetic marking was developed based on these sequences. The effect of light cycles on growth expression was also assessed by measuring the expression of two of these genes, GH and GHR. The relative expression of GHR was not found to be greater in larger fish and no association was found between CCL delayed puberty and GHR expression. GH expression was also examined in fish at sea level. Significant differences in GH expression were measured at only one sampling point, early in the first year in the sea cages in the CCL-treated group. This increase did not occur in the corresponding changes in the staging characteristics of growth and puberty measured at the same time.

Light and photoperiod is a powerful environmental regulator of growth and sexual maturation in fish. Initial studies had indicated that a new type of lights, Cold Cathode ‐ lights (CCL), had much greater effect on growth and sexual development than white halogen light traditionally used in fish farming. In this study we investigated selected candidate gene expression in cod in response to CC ‐ light photoperiod treatment and possible genetic contribution to this response. This effect was evaluated by quantitatively comparing phenotypic traits under the different treatments. On December 2008 (“*”), significant differences were found fish farmed under natural light, in combination with gene expression studies and genotypic family assignments. After hatching the fish was reared from 6 months in indoor tanks under two different light regimes, white halogen light and CC ‐ light. The fish was then transported to sea cages and divided into two groups, one that received continuous CC ‐ light and another that received only natural light treatment. The fish was reared in these sea cages for an additional two years until harvesting. Approximately 2000 individuals from each treatment were genotyped and assigned to different full sib groups. Total body weight, length and gonadal weight were also measured for all individuals. Physiologically, the fish responded clearly to CCL treatment regarding maturity related traits, with less gonadal development in the CCL treated fish. The difference was substantial and the same trend could be observed in all families. The degree of response however differed somewhat between families to some which may signify underlying genetic differences. The effect of CCL treatment on growth related traits was less clear. Apparent growth responses to CCL treatment varied greatly between families and they appeared to be either negative or positive, depending on family and sex. Opposite effects were even observed within families on different sexes. In this project genes associated with growth and maturity were retrieved partly or completely from cod (Gadus morhua). These genes were: Growth hormone (GH), growth hormone receptor (GHR), growth hormone releasing factor (GHR F) and insulin like growth factor 2 receptor (IGF2R). A number of their introns were also obtained and variable microsatellite regions could be identified in intron regions of three of these genes, GH, GHR F, and IGF2R. A method was developed based on the GH and GHR gene sequences to amplify and evaluate expression of these genes in different tissues of cod. GHR expression levels were measured at different sampling points both during the indoor stage where different size groups and treatments were compared and at the outdoor stage where different light treatments were mainly compared. Differences in expression levels between different size groups and between different light treatment groups were insignificant. The light influence is on the GH gene expression, was only observed in the beginning of March early at the sea cage stage and could not be associated with increased growth or delayed reproductive development. The CCL (Cold ‐ Cathode Light) has a single green wavelength that diffuses more effectively throughout the water column than white light. It may therefore mask natural light more efficiently. Still it may be necessary to train fish for the CCL lights and at the indoor stage one half of the juveniles received CCL treatment before transportation to the sea cages. When imprinted and not imprinted were compared negligible difference in gonadal development were, however, observed strongly indicating that prior imprinting to sea cage rearing had no effect.  

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Reports

Pollution monitoring in the marine environment around Iceland 2007 and 2008 / Monitoring of the marine biosphere around Iceland 2007 and 2008

Published:

01/08/2009

Authors:

Hrönn Ólína Jörundsdóttir, Sasan Rabieh, Hulda Soffía Jónasdóttir, Þuríður Ragnarsdóttir, Helga Gunnlaugsdóttir

Supported by:

Ministry for the Environment and Ministry of Fisheries

Pollution monitoring in the marine environment around Iceland 2007 and 2008 / Monitoring of the marine biosphere around Iceland 2007 and 2008

This report presents the results of the Ministry of the Environment's annual monitoring project for the years 2007 and 2008. The aim of this monitoring is to fulfill Iceland's obligations regarding the Oslo and Paris Agreement (OSPAR), as well as the AMAP (Artic Monitoring Assessment Program). The data has been sent to the International Council for the Exploration of the Sea (ICES) database. The Marine Research Institute collects samples and Matís oversees the preparation of samples and measurements of trace elements in the marine environment. The samples are measured at Matís and at the Laboratory of Pharmacology and Toxicology. Various inorganic trace elements and chloro-organic substances were measured in cod caught in Hafró's annual spring rally in March 2008 and in mussels collected at 11 locations around the country in August / September 2007. Monitoring in the marine environment around Iceland began in 1989 and data are collected in database, the report provides overview images for some of the materials monitored.

This report contains results of the annual monitoring of the biosphere around Iceland in 2007 and 2008. The project, overseen by the Environmental and Food Agency of Iceland, is to fulfill the OSPAR (Oslo and Paris agreement) and AMAP (Arctic Monitoring Assessment Program) agreements. The data has been submitted to the ICES databank (ices.dk), collection of data began 1989. Matís ohf is the coordinator for marine biota monitoring and is responsible for methods relating to sampling, preparation and analysis of samples. The samples were analyzed at the Matís and at the Department of Pharmacology and Toxicology at the University of Iceland. Trace metals and organochlorines were analyzed in cod (Gadus morhua) caught in March 2008 and in blue mussel (Mytilus edulis) collected in August / Sept 2007. Marine monitoring began in Iceland 1989.

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Reports

Pure muscle proteins from fish

Published:

01/06/2009

Authors:

Ragnar Jóhannsson, Sjöfn Sigurgísladóttir, Guðjón Þorkelsson, Arnljótur B. Bergsson

Supported by:

AVS, Technology Development Fund

Contact

Guðjón Þorkelsson

Strategic Scientist

gudjon.thorkelsson@matis.is

Pure muscle proteins from fish

Extensive research was carried out into the physical properties of muscle proteins from fish, especially cod. The project Pure muscle protein from fish proved to be another main support for the operations of Iceprotein ehf. during the company's formative years. The report describes the main results in the production process of refined muscle proteins from cuts and blueberries for use in fillets and ready-made products and the development that took place at Iceprotein ehf. when scaling up. The company Iceprotein is almost the result of the work that was put into the project. Fishballs were produced that were later eaten and evaluated and came out well in various ways, fishballs with isolated proteins as well as minced fish deteriorated less during cooking than fishballs that did not contain isolated proteins.

Great effort was used in viscoelastic measurements of cod muscle proteins. The project Pure muscle protein from fish proved to be one of the main pillars in the operations of Iceprotein ehf. in the offset of the company. In this report main results of the scale-up process at Iceprotein are followed through. The company Iceprotein basically spun off from the work done in this project. Fish balls from fish mince and fish protein isolates were prepared cooked, consumed and analyzed, fish balls containing FPI showed less weight loss in cooking than fish balls that did not contain FPI.

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Reports

Effect of modified atmosphere packaging (MAP) and superchilling on the shelf life of fresh cod (Gadus morhua) loins of different degrees of freshness at packaging

Published:

01/09/2008

Authors:

María Guðjónsdóttir, Hannes Magnússon, Kolbrún Sveinsdóttir, Björn Margeirsson, Hélène L. Lauzon, Eyjólfur Reynisson, Emilía Martinsdóttir

Supported by:

AVS Research Fund, Rannís Technology Development Fund

Contact

Kolbrún Sveinsdóttir

Project Manager

kolbrun.sveinsdottir@matis.is

Effect of modified atmosphere packaging (MAP) and superchilling on the shelf life of fresh cod (Gadus morhua) loins of different degrees of freshness at packaging

The purpose of this experiment was to evaluate the effect of aerated packaging (MAP) and supercooling on the quality changes and shelf life of cod pieces of fresh raw material that was processed and packaged after 2 and 7 days of fishing. The experiment was carried out in collaboration with Samherji, Dalvík and Norðlenska, Akureyri in October and November 2007. The fish was stored whole in ice until packing at -0.2 ± 0.1 ° C (2 days from fishing) and -0.2 ± 0.2 ° C (7 days from fishing). The neck pieces were cut in half and then packed (350-550 g) in an airtight container. The composition of the gas mixture was as follows: 50% CO2, 5% O2 and 45% N2. Packaged cod pieces were stored in cold storage at -0.6 ± 1.4 ° C and samples were taken over a 3-week storage period and evaluated by sensory evaluation, microbial and chemical measurements. The age of the raw material during packaging had a clear effect on the sensory evaluation of the pieces. Packing after 2 days led to a prolongation of the freshness symptoms in front of storage. In addition, signs of damage appeared much later than in bites packed 7 days after fishing. The shelf life of pieces after packing on day 7 can be roughly estimated at 4-8 days, but at least 19 days in pieces packed on day 2. This short shelf life of pieces from day 7 can be explained by the development of microbial flora and the formation of volatile pesticides as well as the temperature profile of whole fish before packaging. The effect of different packing dates had a significant effect on the microflora. Thus, the total number of microorganisms was much smaller in pieces packed after 2 days than on day 7 (log 3.7 vs 5.4 / g). This difference can largely be attributed to the varying number of Photobacterium phosphoreum (Pp) in the flesh immediately after packing, but it was not detected during the previous packing on the 3rd day of the experiment (below log 1.3 / g) and on day 8 the number was only log 2.4 / g. On that day, the number of Pp was 1000x higher in pieces packed on day 7 and they were predominant throughout the storage period in this group. On day 8, the number of other pests (H2S-producing bacteria and pseudomonads) was somewhat higher (Δ log 0.6-0.7 / g) in this group compared to the group packed on day 2. These results confirm that P. phosphoreum is one of the main damaging microorganisms in gas-packed cod pieces but also in chilled, whole cod. The results of TVB-N and TMA measurements were in good agreement with microbial measurements, but especially Pp. Low Field Nuclear Magnetic Resonance (LF-NMR) technology was used to measure relaxation times in samples over the storage period. Significantly higher "relaxation times" were measured in chunks packed after 7 days of fishing than in chunks packed 2 days after fishing. It indicates greater binding of water molecules to the environment in the 7-day bites. This is in line with the generally higher water resistance and water content of those samples over the storage period. Overall, the results show the importance of using the freshest ingredients for MA packaging, thus ensuring higher quality and longer shelf life, which should result in a higher price for the product.

The aim of this study was to evaluate the effect of modified atmosphere packaging (MAP) and superchilling on the shelf life and quality changes of fresh loins prepared from Atlantic cod (Gadus morhua) of different freshness, ie processed 2 or 7 days post catch. The study was performed in cooperation with Samherji (Dalvík, Iceland) and Norðlenska (Akureyri) in October and November 2007. The average fish temperature during storage prior to processing on days 2 and 7 was -0.2 ± 0.1 ° C and -0.2 ± 0.2 ° C, respectively. Cod loins (350-550 g) were packed in trays under modified atmosphere (50% CO2 / 5% O2 / 45% N2), stored at -0.6 ± 1.4 ° C and sampled regularly over a three-week period for sensory, microbiological and chemical analyzes . The results show that the raw material freshness clearly influenced the sensory characteristics of packed loins. Processing 2 days post catch resulted in more prominent freshness sensory characteristics the first days of storage. In addition, sensory indicators of spoilage became evident much later compared to MApacked fillets from raw material processed 5 days later. The expected shelf life of the MA-packed cod loins could be roughly calculated as 4-8 days when processed 7 days post catch, but at least 19 days when the cod was processed 2 days post catch. This reduced shelf life of MAP products processed at a later stage was also explained by the temperature profile of the whole fish prior to processing, microbial development and volatile amine production observed. In fact, the day of packaging had a major effect on the microflora development, with lower total viable counts (TVC) in loins processed earlier in relation to time from catch (log 3.7 vs 5.4 / g). This difference could be linked to large variations in levels of Photobacterium phosphoreum (Pp) in the flesh at processing times, being below detection (log 1.3 / g) 2 days post catch but found to increase to log 2.4 / g in early processed loins 6 days later, in contrast to 1000-fold higher Pp levels in loins processed later. Pp was found to quickly dominate the microflora of loins processed 7 days post catch. Similarly, slightly higher levels (Δ log 0.6- 0.7 / g) of other spoilage bacteria, H2S-producing bacteria and pseudomonads, were found 8 days post catch in loins processed later. These results confirm that P. phosphoreum is one of the main spoilage organisms in cod, unprocessed as MA-processed. TVB-N and TMA production corresponded well to the microbial development, especially counts of P. phosphoreum. Low Field Nuclear Magnetic Resonance (LF-NMR) was used to measure the relaxation times of the samples during storage. The samples packed 7 days after catch showed significantly higher relaxation times than samples packed 2 days after catch. This indicates stronger bindings of the water molecules to their environment in samples packed at a later stage. This is in agreement with the generally higher water holding capacity and water content in the samples during storage. Finally, the results demonstrated that delaying processing of raw material is undesirable if it is intended to be MA-packed and sold as more valuable products.

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Reports

Pollution monitoring in the marine environment around Iceland 2006 and 2007 / Monitoring of the marine biosphere around Iceland 2006 and 2007

Published:

01/08/2008

Authors:

Sasan Rabieh, Ingibjörg Jónsdóttir, Þuríður Ragnarsdóttir, Helga Gunnlaugsdóttir

Supported by:

Ministry for the Environment and Ministry of Fisheries

Pollution monitoring in the marine environment around Iceland 2006 and 2007 / Monitoring of the marine biosphere around Iceland 2006 and 2007

This report presents the results of the Ministry of the Environment's annual monitoring project for the years 2006 and 2007. The aim of this monitoring is to fulfill Iceland's obligations regarding the Oslo and Paris Agreement (OSPAR), as well as the AMAP (Artic Monitoring Assessment Program). The data has been sent to the International Council for the Exploration of the Sea (ICES) database. The Marine Research Institute collects samples and Matís oversees the preparation of samples and measurements of trace elements in the marine environment. The samples are measured at Matís and at the Laboratory of Pharmacology and Toxicology. Various inorganic trace elements and chloro-organic substances were measured in cod caught in Hafró's annual spring rally in March 2007 and in mussels collected at 11 locations around the country in August / September 2006. Monitoring in the marine environment around Iceland began in 1989.

This report contains results of the annual monitoring of the biosphere around Iceland in 2006 and 2007. The project, overseen by the Environmental and Food Agency of Iceland, is to fulfill the OSPAR (Oslo and Paris agreement) and AMAP (Arctic Monitoring Assessment Program) agreements. The data has been submitted to the ICES databank (ices.dk), collection of data began 1989. Matís ohf is the coordinator for marine biota monitoring and is responsible for methods relating to sampling, preparation and analysis of samples. The samples were analyzed at the Matís and at the Department of Pharmacology and Toxicology at the University of Iceland. Trace metals and organochlorines were analyzed in cod (Gadus morhua) caught in March 2007 and in blue mussel (Mytilus edulis) collected in August / Sept 2006. Marine monitoring began in Iceland 1989.

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Reports

Oxidation in fish muscle - The role of phospholipids, proteins, antioxidants and the effect of boiling on oxidation in fish muscle

Published:

01/04/2008

Authors:

Rósa Jónsdóttir, Margrét Bragadóttir, Guðrún Ólafsdóttir

Supported by:

RANNÍS Research Fund

Contact

Rósa Jónsdóttir

Research Group Leader

rosa.jonsdottir@matis.is

Oxidation in fish muscle - The role of phospholipids, proteins, antioxidants and the effect of boiling on oxidation in fish muscle

The aim of the project was to increase the understanding of the effects of oxidation in fish muscles, which reduces the taste and nutritional value of fish. The effects of added natural antioxidants or antioxidants were assessed to improve the stability of fish products and thus increase the possibility of using fish in prepared dishes. A phospholipid model from cod was used to examine the effects of stimulants (hemoglobin from cod and char) and inhibitors in the liquid phase from capelin and Icelandic algae. The effect of boiling and added anti-corrosion substances on the taste properties and the formation of a so-called heating taste in boiled fish mince was also examined. The effect of oxidation on membrane phospholipids and proteins in the fish muscle model and in the fish mince during heating and storage was measured by sensory evaluation, color measurements, conventional evolution measurements (TBA), gas spectrometry measurements to identify volatile odorants and electrophoresis capillary capillary peptile and amino acids that affect taste and bioactivity. The relationship between these factors was examined to explain and better understand the oxidation process in fish muscles and the factors that limit the shelf life of prepared fish products. The main negative effects of oxidation on fish quality were the formation of odorants, mainly aldehydes, which are fatty acid degradants. Membrane fat in lean fish can therefore have a significant effect on the taste quality of prepared foods, despite being in small quantities. Oxidative stimuli such as blood in the flesh and boiling led to faster oxidation, which shows that with proper bleeding and mild heat treatment, oxidation could be limited and the taste quality of fish could be better maintained. In addition, oxidation can be reduced through the use of antioxidants. Measurements of the antioxidant activity of capelin broth in a fish muscle model showed that variable external factors such as seasonal fluctuations and the treatment of capelin raw material can affect the antioxidant activity. A novelty in this project is a basic study of the effects of capillaries and algae, as well as changes in the decomposition products during welding, which have a direct effect on the taste quality of the product. Research in this area is being continued in new projects that focus on better looking at natural antioxidants from capelin and algae, as well as their health-promoting effects.

The aim of the project was to study the effect of heating on oxidation of phospholipids, and the role of antioxidants in fish muscle to influence sensory quality and nutritional value. A phospholipid model from cod was used to study the effect of pro-oxidants (hemoglobin from cod and trout) and antioxidants in aqueous fraction of capelin and in seaweed extracts. The effect of heating and the addition of antioxidants on the sensory quality and the development of warmed-over-flavor (WOF) in fish mince were also studied. The development of degradation compounds in washed cod model system during storage and heating was studied by sensory analysis, color measurements, traditional lipid oxidation analysis (TBA) and gas chromatography analysis to identify volatile compounds. Capillary electrophoresis (CE) was applied for the analysis of peptides and amino acids that influence the sensory quality and bioactivity. The correlation between these analyzes was studied to better understand the oxidation processes in fish muscle and to explain factors reducing the shelf life of ready-to-eat fish products. Quality defects related to oxidation of polyunsaturated fatty acids and formation of volatile compounds like aldehydes contributing to rancidity and color changes were enhanced by pro-oxidative effects of blood and cooking. Membrane bound phospholipids are therefore of concern as precursors for off flavor and quality defects in lean fish despite of low fat content. Capelin broth appeared to have antioxidant effects in fish model system whereas press juice from whole capelin exhibited pro-oxidant effects. The outcome of this project is increased knowledge on oxidation in fish muscle to underpin the development of healthy and tasteful fish products of high sensory quality and nutritional values fulfilling the needs of consumers. Continued studies have been established in new projects to further characterize the antioxidant properties and possible health effects of capelin and seaweed extracts.

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Reports

Gender analysis of fish

Published:

01/11/2007

Authors:

Dr. Sigurlaug Skírnisdóttir, Msc. Eiríkur Briem, Msc. Hlynur Sigurgíslason, Dr. Guðmundur Ó. Hreggviðsson, Dr. Sigríður Valgeirsdóttir, Dr. Jónas Jónasson, Dr. Sigríður Hjörleifsdóttir

Supported by:

Technology Development Fund (Icelandic Research Centers)

Contact

Sigurlaug Skírnisdóttir

Project Manager

sigurlaug.skirnisdottir@matis.is

Gender analysis of fish

The aim of the project was to find a gender-related difference between the genetic material of pike and females in salmon, halibut and cod. This information was then to be used to develop a gender analysis test for these fish species. Gene and female repositories for the three species were prepared by subtraction pairing. The sequences obtained in the gene pool were sequenced, palpated, and then plated. The flakes were then paired with genetic material on the hens and females and the binding was assessed for the sexes. The project involved a great deal of technical and market innovation, combining high-tech methods from molecular genetics and information technology to solve the existing market problem in gender analysis in aquaculture. The risk in the project was whether there was a sufficient gender difference in the genome of these fish to detect it by flake analysis. This project was a great challenge and although the final goal was not achieved, it worked out in terms of methodology and great results were obtained. The project was therefore important for development and method development within the companies Stofnfisk, Matís-Prokaria and Nimblegen Systems in Iceland.

The goal of the project was to develop a sex determination method for the three fish species, cod, salmon and halibut. Gene libraries for female and male fishes were produced for the three fish species by using the subtraction hybridization method from whole genomic DNA. Probes were designed for all the sequences obtained and the probes were put on microarrays. The microarrays were hybridized with DNA from both male and female fishes and the difference scored. The risk of the project was to determine if there is enough gene difference between the sexes of these three fish species to be analyzed by using microarrays. The project did not reveal sex determination genes, but this assignment was a big challenge for the three companies Stofnfiskur, Matís-Prokaria and Nimblegen Systems. Many new methods and technical solutions were solved during the project and a large set of results were built up. The project was an important part of the fast growing and development of the companies.

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Reports

Monitoring of the marine biosphere around Iceland in 2005 - 2006

Published:

01/08/2007

Authors:

Sasan Rabieh, Ernst Schmeisser, Eva Yngvadóttir, Ingibjörg Jónsdóttir, Þuríður Ragnarsdóttir, Helga Gunnlaugsdóttir

Supported by:

Ministry for the Environment

Monitoring of the marine biosphere around Iceland in 2005 - 2006

This report presents the results of the Ministry of the Environment's annual monitoring project for the years 2005 and 2006. The aim of this monitoring is to fulfill Iceland's obligations under the Oslo and Paris Agreement (OSPAR), as well as the AMAP (Artic Monitoring Assessment Program). The data has been sent to the International Council for the Exploration of the Sea (ICES) database. The Marine Research Institute collects samples and the Fisheries Research Institute supervised the preparation of samples and measurements of trace elements in the marine environment. The samples were measured at IFL and at the Laboratory of Pharmacology and Toxicology. Various inorganic trace elements and chloro-organic substances in cod were caught in the annual spring survey of the Marine Research Institute in March 2006 and in mussels collected at 11 locations around the country in August / September 2005. Monitoring in the marine environment around Iceland began in 1989.

This report contains results of the annual monitoring of the biosphere around Iceland in 2005 and 2006. The project, overseen by the Environmental and Food Agency of Iceland, is to fulfill the OSPAR (Oslo and Paris agreement) and AMAP (Arctic Monitoring Assessment Program) agreements. The data has been submitted to the ICES databank (ices.dk), collection of data began 1989. The Icelandic Fisheries Laboratories (IFL) (now Matís) is the coordinator for marine biota monitoring and is responsible for methods relating to sampling, preparation and analysis of samples. The samples were analyzed at IFL / Matís and at the Department of Pharmacology and Toxicology at the University of Iceland. Trace metals and organochlorines were analyzed in cod (Gadus morhua) caught in March 2006 and in blue mussel (Mytilus edulis) collected in August / Sept 2005. Marine monitoring began in Iceland 1989.

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Reports

Process control for fishing, processing and processing of salted fish. Effect of cooling after fishing on the muscular structure of cod

Published:

01/08/2007

Authors:

Valur N. Gunnlaugsson, Jónína Ragnarsdóttir, Þóra Valsdóttir, Kristín Anna Þórarinsdóttir

Supported by:

AVS, Rannís Technology Development Fund

Contact

Valur Norðri Gunnlaugsson

Research Group Leader

valur.n.gunnlaugsson@matis.is

Process control for fishing, processing and processing of salted fish. Effect of cooling after fishing on the muscular structure of cod

This report describes the results of a cod image analysis. The effect of cooling methods after fishing on the muscular cod stock was assessed. It was not possible to detect differences in fillets depending on whether the fish had been stored in liquid ice or flake ice in a train or had been cooled separately on deck. Muscle changes during salt fish processing were monitored and the effect of injection was assessed. During salting, cells contracted and the extracellular space increased. There was a clear difference in the fillets depending on whether they were injected or not. During dehydration, the difference due to injection decreased again.

Results from image analyzes on cod are discussed in this report. The effects of chilling methods after catch on microstructure of cod fillets were also evaluated. No significant effects were observed, neither when extra chilling was added on deck nor with regard to different ice types (liquid ice / flake) used for storage of the fish. Changes in the fish muscle during heavy salting were examined and the effects of injection as the initial step in the process studied. During salting muscle cells shrank and the ratio of extracellular fluid increased. Significant effects of injection were observed after salting but during rehydration the difference decreased again.

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Reports

Genotyping Kits for Cod / Genotyping kits for Atlantic cod

Published:

01/06/2007

Authors:

Sigurlaug Skírnisdóttir, Inga Schulte, Sigurbjörg Hauksdóttir, Kristinn Ólafsson, Steinunn Magnúsdóttir, Klara Björg Jakobsdóttir, Christophe Pampoule, Guðmundur Ó. Hreggviðsson, Sigríður Hjörleifsdóttir

Supported by:

AVS Fisheries Research Fund

Contact

Sigurlaug Skírnisdóttir

Project Manager

sigurlaug.skirnisdottir@matis.is

Genotyping Kits for Cod / Genotyping kits for Atlantic cod

The aim of the project was to develop new coding sets for cod (Gadus morhua) based on repeated DNA short sequences (microsatellites). A total of 118 genetic markers were studied. Two ten genetic marker kits have been developed (CodPrint10a and CodPrint10b) and a patent application has been filed for these genetic markers. Almost 300 Icelandic samples belonging to 3 different sampling areas (N-Iceland, SW-Iceland (shallow waters) and SW-Iceland (deep) were analyzed with these 20 genetic markers, but for comparison the samples were also analyzed with nine well-known and widely used genetic markers. These three sample groups were better distinguished by CodPrint10a and CodPrint10b genetic markers than by previously known genetic markers, and the research shows that the new genetic markers are suitable for both stock studies and parental analyzes.

The goal of the project was to develop new genotyping kits for Atlantic cod (Gadus morhua) based on microsatellite markers. A total of 118 markers were analyzed. Two 10 microsatellite markers sets were developed (CodPrint10a and CodPrint10b) and they were used to analyze approximately 300 samples that were collected in the Northeast Iceland, Southwest inshore Iceland and Southwest offshore Iceland. As a comparison the samples were also analyzed with nine previously known markers. A comparison of the new microsatellite loci and the nine previously used, showed that the power of individual discrimination was much stronger with the new microsatellite loci. Indeed, the discrimination of the samples was clearer with much less overlap of the individuals. Together, these results suggest that the new microsatellite loci are powerful and suitable for both population genetic analysis and paternity analysis, due to their high polymorphism and resolution power.

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