By Bill Hauser
I have a couple questions for you. What, exactly, is a minnow? And have you ever seen a minnow in Alaska?
I’ll respond to the second question first. If you think you saw a minnow, you probably did not. Only one species of minnow is found in Alaska and only in the Yukon River and Yukon River drainages upstream of Nulato. I’ve never seen a minnow in Alaska but I have seen lots of minnows... before I came to Alaska.
This brings us back to question one. What, exactly, is a minnow? Sorry, but I need to get a little technical for a bit. All minnows are included in the minnow family, Cyprinidae. As it happens, there are more species of fishes in the Cyprinidae family than in any other family of fishes.
There are more than 2,100 species in the Cyprinidae family. Some are native to North America, Africa, and Eurasia. Of these, 270 species are found in the United States. Still, only one species in Alaska. Because they are found in so many parts of the world, they have evolved in many different habitats . . . and so many species that have special adaptions for those special habitats; e.g., for different ways of feeding and consuming different kinds of food items.
There are several features common to members of the Cyprinidae family. Most species have barbels; those fleshy protuberances that dangle from around the mouth. These sensory organs are prominent on the catfishes but much less so on Cyprinids; which usually have a single small one on each corner of the mouth. They have no jaw teeth but they do have “pharyngeal teeth.” These are bony, tooth-like structures located in the throat on a gill arch. Pharyngeal teeth vary in shape depending on the preferred food items. Flat pharyngeal teeth grind on horny pads on the roof of the mouth. Common carp, for example, have molar-like pharyngeal teeth for grinding food items like small clams, while weed eating cyprinids have more slender blade-like pharyngeal teeth for chopping. Finally, Cyprinid fishes have an anatomical structure called ‘Weberian Apparatus’. This provides an attachment between the air bladder and the inner ear and functions to enhance hearing.
“Minnows” have a reputation as being small fish – usually shiny – and many North American minnows are small and shiny. In fact, many people assume any small, shiny fish is a “minnow”. In fact, minnows – or, Cyprinids - come in many sizes, shapes, and colors. Perhaps the simplest example is the common carp – introduced, by the way, from Europe. These are not small or shiny. Goldfish are members of the minnow family but their appearance has been highly modified by aquarists and, by the way, can grow quite large if they become feral. The smallest Cyprinid matures at about one-half inch in length; the largest, nearly ten feet in length and 285 pounds (found in Asia).
All right. Now, back to the lake chub in the upper Yukon River drainages. It fits in well with the presumed features of a minnow: small and silvery. Most lake chubs are 2 to 3.5 inches in length but occasionally, a few may reach 9 inches.
Outside of Alaska, lake chubs may be found across north America and as far south as Nebraska in lakes and rivers. If you find one, you usually find more. Spawning is in shallow rivers or streams over rocks or gravel. There is no nest. Young fish feed primarily on zooplankton while older fish feed on larger organisms, including insect larvae and vegetation. Few lake chubs live more than 5 years. As for interactions with humans, they are used mostly as bait for other fish.
I know that this stuff is mostly of interest to some “fish nerd” – as my son has categorized me but I hope it gives you a different glimpse into our “Wonderful World of Fishes”. And don’t forget my motto: “All fish are interesting. Some are just more interesting than others. (But beware, that may change daily.”)
Alaska Fly Fishers, 200 W 34th Ave, Suite 1233, Anchorage, AK 99503