Faecal Production Rate - coastal predator
Scientific studies show that the behaviour and life processes of fish have a role in the biological carbon pump, a key process that contributes to the ocean´s function as a carbon sink and reservoir of carbon dioxide, a greenhouse gas. Many fish populations are managed to achieve sustainability and conserve biodiversity, as such, there may be opportunities to secure climate change mitigation benefits through existing management approaches. However, data to quantify carbon flux associated with fish is scarce. As part of a research project that aims to quantify the role of fish in carbon cycling and flux, this experiment will begin to address this lack of data for cod, a commercially important species found in temperate coastal ecosystems throughout the North Atlantic, by quantifying the rate of faecal pellet production.
We expect to keep nine adult cod in 1300L tanks for a maximum of 20 days. Stress to the animals will be minimal: we plan to hold the fish, feed them food that reflects their natural diet, take a small clip from their tail fin, and release them back to their natural habitat. To minimize the stress during handling and data collection, fishes are immediately placed into water and carried to the tanks. Fish are held for the minimum possible time, and are only disturbed to measure and remove faecal material from the tank, which is done using a small hose with suction and a bucket. To minimise stress, the tanks have a large dark plastic sheet with fronds cut in which floats at the surface to act as artificial kelp, giving the fish somewhere to hide. The tanks also have nets placed over the top that prevent animals from jumping out and being injured on the hard floor. Individuals will be regularly monitored during the experiment, with checks every morning and afternoon as minimum, their water parameters will be measured daily and adjusted if necessary. If a fish becomes ill, sustains an injury or appears to have deteriorated to a point from which it is unlikely to recover, it will be humanely euthanised.
Cod are chosen for this experiment to provide some much needed data on the conversion of food to faeces by a coastal predator that is common to temperate coastal ecosystems in the North Atlantic. By using cod, we can combine the experimental data with the vast back-catalogue of data collected on local cod abundance, movement and behaviour along the Skaggerak coast. By combining this existing data with the results from the lab experiment, we will gain valuable insight and can begin to quantify and model the role coastal cod play in carbon cycling. The experimental observations will also provide a reference point for quantifying the role of other coastal predators, and fish with similar diets, in carbon cycling and flux.
We expect to keep nine adult cod in 1300L tanks for a maximum of 20 days. Stress to the animals will be minimal: we plan to hold the fish, feed them food that reflects their natural diet, take a small clip from their tail fin, and release them back to their natural habitat. To minimize the stress during handling and data collection, fishes are immediately placed into water and carried to the tanks. Fish are held for the minimum possible time, and are only disturbed to measure and remove faecal material from the tank, which is done using a small hose with suction and a bucket. To minimise stress, the tanks have a large dark plastic sheet with fronds cut in which floats at the surface to act as artificial kelp, giving the fish somewhere to hide. The tanks also have nets placed over the top that prevent animals from jumping out and being injured on the hard floor. Individuals will be regularly monitored during the experiment, with checks every morning and afternoon as minimum, their water parameters will be measured daily and adjusted if necessary. If a fish becomes ill, sustains an injury or appears to have deteriorated to a point from which it is unlikely to recover, it will be humanely euthanised.
Cod are chosen for this experiment to provide some much needed data on the conversion of food to faeces by a coastal predator that is common to temperate coastal ecosystems in the North Atlantic. By using cod, we can combine the experimental data with the vast back-catalogue of data collected on local cod abundance, movement and behaviour along the Skaggerak coast. By combining this existing data with the results from the lab experiment, we will gain valuable insight and can begin to quantify and model the role coastal cod play in carbon cycling. The experimental observations will also provide a reference point for quantifying the role of other coastal predators, and fish with similar diets, in carbon cycling and flux.