This past weekend I snorkeled a stretch of Sonoma Creek. The creek hosts a run of endangered steelhead, so is closed to fishing for everything except lampreys and crayfish. Access to the stream is limited by the abundant vineyards, all of whom post their property but don't seem to have any qualms at all about degrading habitat... The stream was clear, but obviously nutrient-enriched, and substrates were heavily embedded or covered in thick mats of algae.

Despite this, there were a remarkable number of fish, including Lampetra sp. (ammocoetes only), Lavinia symmetricus (see photos below), Pytchocheilus grandis, Catostomus occidentalis, Gasterosteus aculeatus (photo below), Oncorhynchus mykiss, Oncorhynchus tshawytcha, Cottus asper (photo below), Lepomis cyanellus (introduced), and Hysterocarpus traskii. Two species of crayfish, both introduced, were large and abundant. I thought about keeping a batch for some west-coast etouffee, but then thought about the pesticide load washing off of all of those grapes upstream... That said, for a small (~10m across) stream in this part of the country, that's pretty good diversity. The Lavinia appeared to be getting ready to spawn, some were downright colorful.

At one point I heard some splashing upstream, and crept up through a riffle to investigate... there was a river otter playing in the pool above! It cavorted around for about 5 minutes before it finally realized I was there. Too far away for good photos, though.

It is interesting to see fishes from western part of NA. Nice UW pic The minnow reminds me of some East Asian cyprinids.