Camilla and the evolving salmon lice

Camilla is working with her thesis entitled Intensive aquaculture: Life history responses in energy allocation towards offspring in salmon lice (Lepeophtheirus salmonis).

Thesis description:

Intensive aquaculture is one of the fastest growing forms of food production in the last 30 years. This has resulted in an increasing number of host for parasites, like the ectoparasitic salmon louse (Lepeophtheirus salmonis). The lice that are best able to use this new host resource will therefore have a fitness advantage over the other lice. In salmon farms the lice are also exposed to an additional selection pressure in the form of pesticides. In the salmon farms it would therefore be expected that the “farmed” lice should invest more in a faster reproduction in comparision to the “wild” lice that are expected to invest in a longer lifespan as well as investing more in each offspring. Because we assume that the lice only have a certain amount of energy they can use, we expect a trade-off between faster reproduction and the production of lots of offspring, and the the energy the lice invests in each of their offspring. But in the salmon farms, a lower investment is not necessarily an disadvantage as they live in an environment with lots of potential hosts, as opposed to the case for the “wild lice” where the hosts are more dispersed.

If it is true that salmon lice from areas with salmon farming are selected for faster maturation and invests less in each offspring, we predict that the copepodites (the infective stage of the salmon lice) will have a poorer survival when compared with the “wild lice”. In her master project, Camilla H. Jensen, supervised by Arne Skorping and Olav Moberg, is therefore using copepodites from salmon lice to look at how intensive aquaculture has affected the life-history choices of salmon lice with regards to energy allocation towards offspring.