Pilot experiment to estimate metabolic rates in marine larval fish
Early life stages are arguably the most vulnerable life stage to environmental stressors. Estimates of metabolic rates can help us understand physiological constrains at certain developmental milestones (e.g. metamorphosis) or certain environmental stressors (e.g. increased temperatures). However, obtaining reliable estimates of metabolic rates on fish larvae is very challenging due to technological limitations related to their small sizes. Here we will test a prototype for a swimming respirometer designed for fish larvae. Once operative, this respirometer will help better understand the energetic challenges larvae experience under different environmental scenarios.
Stress to animals in this pilot experiment will be minimal. We will use fish from two aquaculture farms (Norsk Oppdrettsservice AS and Landbasert Akvakultur Norge AS), introduce them individually in the respirometer to observe their behavior and measure oxygen consumption, and then return the fish to the tanks.To minimise stress, these measurements will be done under low illumination conditions at the aquaculture facility where the fish are kept, avoiding the stress of transport to experimental facilities. Fish behavior will be continuosly controlled visually via a video system (from a distance to avoid unneccesary disturbance). This surveilance will allow us to quickly stop the experiment if we see any signs of distress in the fish. The fish will be then be allowed to rest and the humane endpoint assessed if the signs of distress persist.
For this pilot experiment we plan to use a maximum of 10 larvae from lumpfish and 10 from ballan wrasse. This is the minimum number needed to test different fish sizes and shapes. This pilot experiment will be our proof-of-concept that this design works and can be later used to estimate active metabolic rates in other species.
Stress to animals in this pilot experiment will be minimal. We will use fish from two aquaculture farms (Norsk Oppdrettsservice AS and Landbasert Akvakultur Norge AS), introduce them individually in the respirometer to observe their behavior and measure oxygen consumption, and then return the fish to the tanks.To minimise stress, these measurements will be done under low illumination conditions at the aquaculture facility where the fish are kept, avoiding the stress of transport to experimental facilities. Fish behavior will be continuosly controlled visually via a video system (from a distance to avoid unneccesary disturbance). This surveilance will allow us to quickly stop the experiment if we see any signs of distress in the fish. The fish will be then be allowed to rest and the humane endpoint assessed if the signs of distress persist.
For this pilot experiment we plan to use a maximum of 10 larvae from lumpfish and 10 from ballan wrasse. This is the minimum number needed to test different fish sizes and shapes. This pilot experiment will be our proof-of-concept that this design works and can be later used to estimate active metabolic rates in other species.