Temporarily impaired vision may have the same potentially disastrous effects for fish as for humans in picking a partner for mating, new research shows.
Josefin Sundin, a Ph.D student at the Evolutionary Biology Centre (EBC) of Uppsala University, has studied how the broad-nose pipefish (Syngnathus typhle) reacts to intensive algal bloom, in later years a recurring phenomenon in the Baltic Sea and other Swedish waters.
In that species, the male fish gets pregnant and since the quality of the eggs produced by the females is better, with a better potential for survival, the bigger she is, it is advantageous for him to find as big a partner as possible.
In clear water he has no problem to do so, but Sundin found that the worse he could see, because of the algae, the bigger was the chance that he would pick a partner that was not the best for him.
“Not very unlike late night in a singles bar”, she commented.
She said that the same results were found for a few other species, e.g. Three-spined stickleback (Gasterosteus aculeatus), but it still remains to be studied whether good vision is a decisive factor on the mating market for more common fish like pike or salmon.