Local resident: An overabundance of algae must be harmful to the smaller fish in this pond. During the fifteen or so years that I have lived here, the few times that I have seen large numbers of dead small fish wash ashore in late summer coincide exactly with the times that I have noticed abnormally large amounts of algae in the water. The local resident's argument is most vulnerable to criticism on the grounds that it ['presumes, without providing justification, that smaller fish are somehow more susceptible to harm as a result of overabundant algae than are larger fish', 'ignores the possibility that the overabundance of algae and the deaths of smaller fish are independent effects of a common cause', 'ignores the possibility that the same cause might have different effects on fish of different sizes', 'fails to consider that the effects on smaller fish of overabundant algae may be less severe in larger bodies of water with more diverse ecosystems']