Reports

Culturing and utilization of marine algae from the sea surrounding Iceland

Published:

01/06/2012

Authors:

Jónína Þ. Jóhannsdóttir, Friðbjörn Möller (student), María Pétursdóttir, Hlynur Ármannsson, Kristinn Guðmundsson, Rannveig Björnsdóttir

Supported by:

Fisheries Project Fund

Culturing and utilization of marine algae from the sea surrounding Iceland

The variability of floating algae is high, but in the sea in the northern hemisphere, diatoms and whip algae are most common. Floating algae have been cultivated in Japan since about 1960 and used to enrich the nutritional content of various foods and thus have a positive effect on the health of both humans and animals. The high levels of omega 3 (ω3) and ω6 fatty acids in cold seaweed also make them an interesting crop. The main goal of the project was to isolate algae from the sea off Iceland and grow them in a laboratory under different conditions. The breeding of 4 species of cold-water algae, Phaeodactylum tricornutum, Microcysitis sp., Chlorella sp. Has been successfully isolated and maintained. and Dunaliella salina. The fat content and percentage of ω3 fatty acids were highest in P. tricornutum, but the species all contained a relatively high percentage of ω3 fatty acids and were easy to grow, although their growth varied depending on the situation. The results indicate that the fat content and ratio of different fatty acids vary according to growth stages. The results also show that equidae eat Microcystis sp. and Chlorella sp. and therefore it may be interesting to use these species for the enrichment of aquatic animals used as live feed animals in aquaculture of sea larvae in aquaculture. The project has resulted in new projects where work continues on the types of algae that have been successfully grown in pure cultivation. The aim of these studies is, on the one hand, to further develop methods of cultivation with the aim of increasing the proportion of fat and processing fats from algae, and, on the other hand, experiments with the cultivation of the species in wastewater from fish farms. An experiment has also been started in the breeding of cod juveniles with the use of these species of algae in the enrichment of feed animals of larvae.

Phytoplankton is the autotrophic component of the plankton community. Phytoplankton has been cultured since 1960 in Japan for a variety of purposes, including foodstock for other aquacultured organisms and a nutritional supplement. The most abundant groups of microalgae around Iceland are the diatoms and dinoflagelleates. High omega 3 (ω 3) and ω6 fatty acid content in cold water marine algae make them interesting for culturing. The main goal of the project was to search expedient plankton suitable for culturing and investigate the effects of different culture conditions. Four species of cold ‐ water algae have been isolated in monocultures, Phaeodactylum tricornutum, Microcysitis sp., Chlorella sp. and Dunaliella salina. P. tricornutum was found to contain the highest fatty acid and content3 content but all species were relatively high in ω3 content and were easy to culture. The results indicate that the fatty acid composition differed with respect to growth stages. The results also indicate that rotifers grazed on Microcystis sp. and Chlorella sp., thereby making them interesting for enrichment of the live prey commonly used in marine aquaculture. The project has resulted in new projects with further studies on the isolated species and developing methods for increasing their fat content, processing methods for extraction of the fat content and culturing using waste water from aquaculture farms. Also, two of the algae species are presently being used for enrichment of the live prey of cod larvae in an ongoing project.

View report

Reports

Experimental production of natural zooplankton and the quality of stored eggs

Published:

01/01/2011

Authors:

Jónína Þ. Jóhannsdóttir, Friðbjörn Möller (student), María Pétursdóttir, Rannveig Björnsdóttir

Supported by:

Fisheries Project Fund, University of Akureyri Research Fund, Student Innovation Fund

Experimental production of natural zooplankton and the quality of stored eggs

The marine gliding community of the sea is very diverse and species-rich, and the glide contains a high proportion of n-3 fatty acids as well as proteins, pigments, wax esters and chitin. In addition to being the natural food of sea fish larvae, plankton contain a high percentage of fatty acids that are suitable for human consumption. For this reason, it is interesting to utilize this source of nutrients by cultivating under controlled conditions on land and accessing all year round. The main goal of the project was to develop methods to maintain the cultivation of Acartia tonsa that was hatched from resident eggs and to cultivate Acartia longiremis from plankton in the sea from Eyjafjörður, as well as to study the hatching rate of eggs after storage. A. longiremis is much more sensitive in all treatments compared to A. tonsa and requires a lower culture temperature. Facilities for the breeding of plankton and algae have been set up at the Matís, HA and Hafró laboratories in Akureyri. Conditions in the laboratory proved to satisfy the needs of both species for growth and maintenance, but the results indicate that better conditions need to be developed for the storage of A. longiremis eggs in order to increase their hatching rate. Results of experiments in which halibut juveniles were fed with Acartia spp. also give evidence of faster growth of halibut larvae and although there was evidence that metamorphosis was somewhat delayed, it seemed to be more successful.

The community of zooplankton includes many species and contains high proportion of n ‐ 3 fatty acids in addition to proteins, wax esters and chitin. Apart from being the natural food for marine larvae, zooplankton includes large quantities of high quality oil suitable for human consumption. It is therefore of importance to utilize this nutritional source by culturing zooplankton at controlled conditions throughout the year. The main goal of the project was to develop methods for maintaining cultures of Acartia tonsa that were hatched from dormant eggs, and to maintain cultures of Acartia longiremis collected from the marine environment in Eyjafjördur. The hatching rate of eggs following storage was furthermore investigated. Facilities for culturing of both zooplankton species and algae at controlled conditions have been set up in the laboratory and A. longiremis proved to be more sensitive to handling and require lower culturing temperatures compared with A. tonsa. Culturing conditions proved to fulfill the needs of the Acartia species for normal development and egg production. The results, however, indicate that conditions during egg storage need to be further developed for improved hatching rate of A. longiremis eggs. Offering Acartia spp. to halibut larvae may have resulted in improved growth and metamorphosis of larvae, however with delayed metamorphosis.  

View report
EN