Aquascope Facts

Accordingly we have both sets of hypotheses:
    1. If one species of mussel is removed, then the other species will increase in numbers.
    2. If mussels are moved to an area with another saline content, several of them will die compared to if they were moved to areas with the same salinity.


To be able to distinguish among alternative hypotheses derived from the various models that might explain our observations, we must carry out the relevant experiments. We have to experimentally create conditions so that the different predictions will be able to occur. The relevant experiments are those that include these conditions and then are compared with sites that continue to be in the same condition as those we initially observed. We accordingly assume greater changes in those areas that we changed in accordance with the hypothesis compared to areas that have not been changed.


To test the first hypothesis we must initially reduce the number of individuals of one of the mussel species from certain areas so we can see if there will be a change in the number of mussels of the other species in these areas. But we also need controls to be able to see if an eventual increase in numbers within the experiment area was dependent of the reduction of the other species. There can for example occur a large scale increase in the numbers of mussels along the coast that was not dependent of the removal of the supposed competitors in the experimental areas. Therefore, we have to compare what occurs to the number of mussels within the experimental areas with what occurs within the control areas, where supposed competitors are still present.
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Bo Johannesson | Martin Larsvik | Lars-Ove Loo | Helena Samuelsson