Roaming more widely may not be healthy for the salmon.

Whether it is or is not, is not a function of the cocaine though, but rather idiosyncrasies of the wider ecologies the salmon are in.

If roaming more widely introduces them to more productive food opportunities (or, lower predation) than their closer ecology, then it would be beneficial for them. If it does not, then it wouldn't be. Neither context is determined in the basic finding that cocaine causes them to roam more widely.

They’re in a better mood though.

I think another study is in order examining how cocaine affects breeding habits.