Effekt av berikad vs standard odlingsmiljö på beteende och tillväxt hos lax

• Main Author: Björndotter, Erica
• Format: Bachelor Thesis
• Language: Swedish
• Published: Karlstads universitet, Institutionen för miljö- och livsvetenskaper 2015
• Subjects: Salmo salar; enriched rearing; hatchery conditions; berikad odling; odlingsmetoder; Atlantic salmon
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-37162

ABSTRACT The farming of salmon in hatcheries has been used to compensate for the decline of many wild populations due to human activity. Recent evidence has indicated that standard farmed salmon have a higher mortality than wild fish, leading to the question of whether hatchery conditions can be altered to improve survival of stocked salmon. The purpose of this study was to compare the behavior and growth of hatchery-raised Atlantic salmon (Salmo salar) raised under standard conditions vs varied (enriched) hatchery conditions. The hypothesis was that fish from enriched rearing would grow faster, presumably due to more efficient foraging, resulting in less total movement, In addition, I predicted that salmon from enriched conditions would have a higher biomass of food in their stomachs than fish reared under standard conditions. Salmon from the two different groups, enriched and standard, were held separate during their first 12 months of life. The following nine months the fish were raised together in semi-natural outdoor tanks. Behavior and growth of the fish were measured during this latter period. The results showed no support for my hypotheses. Biomass of food contents and summer and winter growth did not differ between treatments. I did find, however, that fish farmed in enriched environments were more active during the summer than fish raised under standard conditions. This suggests that early rearing conditions affect the behavior of the fish, but it is unclear if this effect has any bearing on survival of the fish when stocked in rivers. SAMMANFATTNING Odling av laxar i anläggningar har använts för att kompensera för den minskning som sker i många vilda populationer på grund av mänsklig aktivitet Nutida bevis har indikerat att lax odlad inom standardiserade förhållanden har högre dödlighet än vild fisk, vilket leder till frågeställningen om hurvida odlingsförhållanden kan utvecklas för att förbättra överlevnaden hos utsatt odlad lax. Syftet med denna studie var att jämföra beteende och tillväxt hos ...