Alabama has more species of freshwater fishes than any other state. Shades Creek Greenway is a great place to meet the fishes that help make Alabama internationally famous among fish enthusiasts and biologists. Two of the fishes found at the greenway are endemic to (found only in) the Mobile River Basin – the Silverstripe Shiner and the Alabama Hog Sucker. The Basin is all the area in the Southeast whose surface waters drain to Mobile Bay. Two-thirds of the Basin are within Alabama.
To get acquainted with the creek’s fishes, grab a dip net and a bucket and head to the Greenway. Find a footpath leading to the stream bank from the greenway – there are many – and scramble down the bank to a shallow section of the creek. (Before you go, be sure to read our safety tips on urban creek exploration at the end of this article.)
Riffles are the best place to chase minnows with a dip net. These are shallow sections of the stream where the water tumbles over rocks. The first fishes you’ll see will probably be shiners. These are silvery minnows in the family Cyprinidae. This group has more species of fish than any other family of freshwater fishes in North America. They travel in fast-moving schools, so you’ll need to be lightning-fast with your net to catch them. They are worth the effort, however. Seen from above, shiners are a dull gray or light brown. But catch them, and you’ll see the silvery flanks that earned them the nickname “shiner.” During breeding season, males of some species will sport blues, pinks, reds, and other bright colors that might seem unlikely for little stream fishes.
One of the most common minnows along the Greenway is the Silverstripe Shiner, one of the species endemic to the Mobile River Basin. It feeds at mid-depths and near the surface, where it waits and watches for small animals drifting downstream. Little else is known about its biology.
Another common minnow found along the greenway is the Blacktail Shiner. Its feeding habits are similar to the Silverstripe Shiner, but it differs from the Silverstripe Shiner in several ways. The Blacktail has a bulkier body and a much larger range (Texas to Georgia) and has been more carefully studied. During the breeding season, a male will select and defend a crevice in the stream bottom. Males compete over crevices and often get into contests where they try to intimidate one another. Sometimes this leads to physical fights during which they ram into one another. When not battling other males, males attempt to woo passing females with ritualized body postures and displays. If a female finds a male and the crevice he defends acceptable, she will deposit her eggs into the crevice. The male will then deposit his milt on top of the eggs to fertilize them. The fertilized eggs must stick to the crevice walls to avoid being swept downstream. Any that don’t stick are eaten by the defending males, not only for nourishment, but because the drifting eggs would attract predators.
Another common shiner in the creek is the Largescale Stoneroller. Stonerollers are plant-eaters that scrape algae off of rocks. Stonerollers are so-named because males will push gravel out of the way to make a nest. The males then defend the nest from other males and predators, all the while trying to attract females to spawn. The female’s eggs have a sticky surface that helps them become lodged in the spaces between small rocks. After the fertilized eggs are secure, males defend the nest for a while longer. Several days later, the larvae hatch and swim off to feed and grow on their own.
The Alabama Hog Sucker is a larger fish found in the riffles and nearby run habitats. Runs are slightly deeper habitats where the current is a little slower and rocks do not break the surface. The hog sucker is in the family Catostomidae, a group commonly known as the suckers. The species is endemic to the Mobile River Basin. The Hog Sucker has a large blocky head and, like most suckers, its mouth is on the undersurface of the head – a perfect position for slurping up insects and other invertebrates from the crevices between rocks. The Hog Sucker is camouflaged with light brown and charcoal blotches on its upper surface that help it blend in with rocks on the bottom. Hog Suckers are sometimes followed by shiners, which catch the small invertebrates they stir up as they feed.
Pool habitats – deeper stream sections with slow currents – are good places to find the Western Mosquitofish, a small species in the guppy family, Poecilliidae. These fishes prefer still waters, where they patrol the surface for mosquito larvae and other small invertebrates. Also dwelling in the pools are Largemouth Bass and several species of sunfish (bream), including Bluegill. These fishes are larger and faster than others along the greenway. Bring a fishing pole, bait, and tackle to catch these species.
Safety tips for urban creek exploration:
- Take a rain check: Never enter the stream if it has been raining. Water levels can rise quickly, and pollutants from stormwater runoff can be high.
- Boot the foot: Wear shoes or boots that cover your entire foot. Rocks can be sharp, and there can be glass or metal debris on the stream bottom.
- Travel on gravel: Avoid stepping on big rocks and logs, which may be covered in slick algae. Avoid stepping in mud, as there may be sharp objects hidden below.
- Wash on return: When you return, wash up with soap and clean water.
- The nose knows: Avoid areas where the water smells unpleasant or is discolored. Try farther upstream.
R. Scot Duncan