Forsøksdyr: Parental exposure to petroleum on fertilization success and embryo development in Atlantic cod

Godkjenningsdato 05.02.2020

Godkjenningsperiode 18.02.2020-25.05.2020

1 Formål
The main objective of this study is to expose adult Atlantic cod to crude oil water soluble compounds in order to contaminate the gametes and study the effects of such parental exposure on the fertilization success and development of Atlantic cod early life stages (ELS, embryos and larvae).

2 Skadevirkninger
The adult A. cod will be exposed to a simulated oil spill (only the water soluble fraction) during 4 weeks at Havbrukstasjon i Tromsø. The levels of oil in the water will be so low that no visible effects are expected to be seen on the fish. The levels in questions will only be able to induce specific enzyme activities and metabolite production from the components bioavailable to the fish. The adult fish will be stripped for eggs and sperm and euthanised once it is considered that the we have obtained eggs from enough females (at least 5 out of 12 per treatment) for the embryo part. Stripped eggs and sperm will be in vitro fertilised and be maintained in clean flow-through water until reaching 45 days post hatch. The ELS will remain in the incubators without unnecessary intervention by the staff until hatch. At hatch, some larvae will be photographed and euthanised. After onset of exogenous feeding, larvae will be sampled for behavioural analyses. Any sampling will be terminal and preceded by anaesthesia, except for behavioral analyses. The sampling of the feeding larvae is expected to give moderate discomfort. The largest stress moment will be related to the behavioural analyses of larvae due to handling over a short period of time (1hours). In this study, the indirect exposure via the parents will likely cause reduced toxic effects on the ELS than if direct exposure of embryos had been conducted.

3 Forventet nytteverdi
This study is primordial for a holistic understanding of the risk from accidental oil spills and has immediate relevance for ongoing debates on the drilling for oil in the Lofoten-Vesterålen area. It will provide important knowledge for the improvement of current modelling efforts to determine the effects at the population level.The project has a high “end-user” relevance, with data relevant in ecological risk-based frameworks and is, as such, of great interest for environmental managers, the industry and other stakeholders.

4 Antall dyr og art
16 males and 24 females of Atlantic cod (Gadus morhua) and 300000 first feeding larvae.

5 Hvordan etterleve 3R
Replace: the study of the transfer of contaminants from parents to offspring can not be study using other alternatives. Reduction:The number of adults exposed is a minimum to guarantee the successful stripping of enough fish to provide enough gametes for further study given our endpoints. Refine: The experiment uses all available methods and knowledge to reduce discomfort in the organisms. The team has long experience in this type of set-up and uses levels of contaminant known to cause only cellular effects. Protocols for rearing are following strict regulation with regard to animal welfare.