Forsøksdyr: Cost of life-history adaptations: Multiple trait consequences of fisheries-induced evolution

Godkjenningsdato 12.02.2020

Godkjenningsperiode 12.02.2020-31.07.2020

1. Formål

The objective of this project is to understand how costs of adaptation to a single external stressor are paid in terms of changes in multiple, fitness-related traits, using an empirical, cross-disciplinary approach anchored in the fields of behaviour ecology, evolutionary biology, physiology and ecology. This project will help quantify and reveal how costs of strong directional selection on size are being paid. Existing studies have mostly focused on single traits or trade-offs between life-history traits (maturation, growth) only.

2. Skadevirkninger

Fish will be kept under optimal conditions with favourable light regime, highly monitored water conditions and temperature, provided high quality food daily. Most severe experiments in this application are of moderate severity. Humane endpoints will be implemented in case fish start showing any signs of distress or abnormal behaviour, then fish will be euthanized using an anesthetic overdose.

3. Forventet nytteverdi

We will utilize established experimental populations, already existing in the laboratory and subjected to different harvesting pressures. Later estimate life-history traits (age and size at maturation, size at birth, offspring number, fecundity, quality of offspring), physiological traits (aerobic scope, anaerobic capacity, minimal metabolic rate, swimming performance), behavioural traits (habituation and exploration in new environments, willingness to forage, fishing gear avoidance, cognitive ability), parasite resistance. Animals are going to be subjected to post mortem measurement of cortisol, morphological traits (brain size) and molecular analysis to test parasite resistance and behavioural traits. These experiments will allow us to draw conclusions about how fisheries-induced evolution affects traits which are not under direct selection, but co-evolve as a result of life-history trait evolution.

4. Antal dyr og art

The test fish are offspring from the Evofish harvesting experiment (please see FOTS application Id 1639 and Id 4337). Laboratory population with origin from wild fish from Trinidad (Caribbean), Poecilia reticulata (guppy). 576 individuals.

5. Hvordan etterleve 3R

Pilot studies are going to be performed in advance on a small number of animals (36) to refine study techniques before the main experiment.
468 fish will be reused in all (behaviour, physiology and parasite resistance) experiments. After euthanasia fish are going to be subjected to post mortem measurements of cortisol, morphological measurements (brain size) and molecular analysis to test parasite resistance and behavioural traits.
This experiment is refined as much as possible to use the least number of animals, but getting enough statistical power at the same time accounting for natural mortality, sex differences and inter -individual variation per each family in all experiments.