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.  

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Reports

Possibilities for the production of natural zooplankton for the first feeding of marine larvae

Published:

01/10/2008

Authors:

Jónína Þ. Jóhannsdóttir, Rannveig Björnsdóttir

Supported by:

Verkefnasjóður Sjávarútvegsins / Project fund of the Ministry of Fisheries

Possibilities for the production of natural zooplankton for the first feeding of marine larvae

The overall goal of the project is to make an assessment of the possibilities of producing natural zooplankton for use in the early stages of aquaculture in Iceland. The quality and supply of larvae is one of the main problems in aquaculture today. The larvae of most marine fish need live prey when the pre-nutrition of the peritoneum is exhausted, in which case the supply of live feed animals is necessary until the larvae begin to absorb dry food. Domestic farms have primarily used rotifers and artemia that need to be bought from abroad and bred in the farms. There is a lack of the right composition of nutrients in these feed animals compared to zooplankton, which is the natural food of marine fish larvae, and research shows that the use of zooplankton provides increased yields and improved larval growth. The supply of natural zooplankton is seasonal, but the cultivation of various species has been tried in several parts of the world with good results. The results of research indicate that it is possible to cultivate various types of crayfish in sufficient quantities for production for juvenile farms. Many species of plankton are found in the marine ecosystem by the land that could be suitable for aquaculture, such as redfish, A. longiremis and Oithona spp. It is planned to apply for a research grant to the fund for the installation of facilities and experiments with the cultivation of selected species (s) of zooplankton.

The main goal of this project was to evaluate the potential for production of natural zooplankton for production of marine fish larvae in Iceland. Satisfactory quality and survival of larvae are one of the main problems in marine aquaculture. Marine larvae are fed live zooplankton during the first feeding stages, when the contents of the yolk sac are spent. Icelandic producers of marine fish larvae mainly use imported rotifers and Artemia as live feed. Copepods are the main food source of marine fish larvae in their natural environment and previous research indicate that the nutritional value of rotifers and Artemia is not adequate for successful development of the larvae. Successful growth and survival of larvae have been achieved using natural zooplankton. However, seasonal growth of natural zooplankton species prevents their use in commercial production of fish larvae. Copepods have been successfully cultured and there are indications that copepods can be cultured as feed in the production of marine fish larvae on a commercial scale. Various zooplankton species are found in the Icelandic marine ecosystem and that may be ideal candidates for culturing eg Calanus finmarchicus, A. longiremis and Oithona spp. As a next step, we will apply for funding of a larger project where the aim is to develop experimental facilities and carry out experimental cultures of selected species.

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