who state the ability of European catfish
to tolerate DO concentrations of up to 1.5 mg·L−1 in the long term. Values between 1 and
1.5 mg·L−1 are said by these authors to be critical; nevertheless, they point out that catfish
can sustain these conditions for 24 h. Fish in our study also survived and exhibited movement
under conditions with DO concentrations of 1.3 mg·L−1.