Ecology Kyle Griffiths

Introduced California Fish: the Good and Bad

by Kyle Griffiths

As an original resident of the far West, a recent transplant from the Pacific Coast, I was under a subconscious misapprehension about fish diversity in North America. Roughly speaking, the further east you go, the more kinds of fishes there are. The peak fish diversity in the US is in the South; there are 244 native fish species in Kentucky, for instance. I’d like to see some of the members of the darter family and some cyprinodonts (killifish and topminnows) of the East, lovely fish that have few representatives here in the West. Altogether, we have less than one hundred types of native fish in California, a dozen or so in the San Joaquin watershed; if I was expecting hundreds of fish species from moving here, I was destined to be disappointed.

The Rockies, rearing up millions of years ago, cut California and the arid West off from the centers of fish diversity in the East. East of the great divide there are dozens of sunfish: bluegill, pumpkinseed, longear sunfish, green sunfish, warmouth, largemouth bass and smallmouth bass, and the spotted bass, just off the top of my head. In California we have one native sunfish, called the Sacramento perch (which is endangered). But, I can see some of these non-native sunfish here in Fresno, because some thoughtful soul decided to meet me halfway, in fact more than halfway, since I only travelled a hundred or so miles east, to bring the fish of the East to California. I can see bass in the river a short drive from my house, and what’s more, I can see bluegill in the canal a short walk from my front door. In fact, I can see more types of fish here in Fresno than my home waters. Not that I’m complaining about seeing a local fisherman hook a thresher shark or running into an ocean sunfish on a surfboard, like my brother did a few weeks ago.


Pacifica Pier on the day after Thanksgiving

There are downsides to introducing fish outside of their range. Introduced fish compete with natives for the resources, seldom in a pristine state, that are available. I’m not trying to minimize their effect, but if I hadn’t had early experiences with both native and nonnative fish I doubt I would have been interested in pursuing aquatic biology. Biologists think on global scales, of evolutionary lineages hundreds of millions of years long, researching whatever corner of the earth holds the particular set of circumstances they are interested in, and this global perspective has accompanied a sentiment that the earth is not just to study, but to reshape. Stocking fish outside their native range was a practice of scientifically literate people to improve fishing in new territories. We wouldn’t do that today, but the way we’ve altered the landscape, or fishscape, of our country is part of our heritage.