Effects on feeding rates and feeding frequencies on growth and cataract development of Lumpfish (Cyclopterus lumpus L.).
This project is a continuation of related studies on lumpfish undertaken at Gifas. The focus of this project is to directly compare growth rates and health of juvenile lumpfish fed different daily feeding rates and frequencies as well as different diet types.
The biological control of sea lice through the use of cleaner-fish has become a feasible option due to the increased occurrence of resistance towards medical treatments in salmon lice, Lepeophtheirus salmonis. As a cold-water cleaner-fish alternative the common lumpfish (Cyclopterus lumpus L.) has been used more frequently with production in Norway increasing dramatically over the last three years.
However, efficient use of lumpfish in terms of the proportion of fish that graze sea lice, is dependent upon the establishment of healthy and robust populations. Recently, there are indications that the incidence of cataracts is prevalent in lumpfish populations. Veterinaries assessing health of lumpfish stocked in salmon cages have observed cataracts in 100% of populations after five months at sea.
A recent study undertaken showed cataract development in lumpfish populations was possibly related to disturbed metabolism/ malnutrition, visualized as very high values of selected amino acids in different tissues from sampled fish. This can cause osmotic imbalance in fish tissues and cataract development, or is a consequence of osmotic imbalance.
If cataracts are associated with sub-optimal nutrition, then further research in nutrition with lumpfish is therefore necessary. One way forward is to test different feed formulations such as marine low energy feed; low protein feed or feed with functional additives. Alternatively, given that juvenile lumpfish display a large ontogenetic variation in optimum temperatures for growth demonstrated by high growth rates and previous studies on Atlantic salmon have shown that cataract development can occur during periods of rapid growth then controlling the amount of feed juvenile lumpfish consume may alleviate the potential for cataract development. Pellets used in today’s aquaculture industry may have as high as 4 or 5 times the energy value for an equivalent volume of wild food due, in part, to the low water content of pelleted feed. It follows logically that fish fed high energy diets require less feed in terms of volume, than do those feeding on low energy diets.
This research focus will be an integral part of the research project "LUCINFER – Optimal bruk av rognkjeks til avulsing av oppdrettslaks" funded by NFR (attached description).
The biological control of sea lice through the use of cleaner-fish has become a feasible option due to the increased occurrence of resistance towards medical treatments in salmon lice, Lepeophtheirus salmonis. As a cold-water cleaner-fish alternative the common lumpfish (Cyclopterus lumpus L.) has been used more frequently with production in Norway increasing dramatically over the last three years.
However, efficient use of lumpfish in terms of the proportion of fish that graze sea lice, is dependent upon the establishment of healthy and robust populations. Recently, there are indications that the incidence of cataracts is prevalent in lumpfish populations. Veterinaries assessing health of lumpfish stocked in salmon cages have observed cataracts in 100% of populations after five months at sea.
A recent study undertaken showed cataract development in lumpfish populations was possibly related to disturbed metabolism/ malnutrition, visualized as very high values of selected amino acids in different tissues from sampled fish. This can cause osmotic imbalance in fish tissues and cataract development, or is a consequence of osmotic imbalance.
If cataracts are associated with sub-optimal nutrition, then further research in nutrition with lumpfish is therefore necessary. One way forward is to test different feed formulations such as marine low energy feed; low protein feed or feed with functional additives. Alternatively, given that juvenile lumpfish display a large ontogenetic variation in optimum temperatures for growth demonstrated by high growth rates and previous studies on Atlantic salmon have shown that cataract development can occur during periods of rapid growth then controlling the amount of feed juvenile lumpfish consume may alleviate the potential for cataract development. Pellets used in today’s aquaculture industry may have as high as 4 or 5 times the energy value for an equivalent volume of wild food due, in part, to the low water content of pelleted feed. It follows logically that fish fed high energy diets require less feed in terms of volume, than do those feeding on low energy diets.
This research focus will be an integral part of the research project "LUCINFER – Optimal bruk av rognkjeks til avulsing av oppdrettslaks" funded by NFR (attached description).