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Tuesday, May 22, 2012

Tiny fish: Castleberry's Jordan Creek is full of native treasure

tiny fish 040.jpgA tiny spotted bass, a few months old, is a perfect miniature of its parents. Ken Weathers, an Alabama Division of Wildlife and Freshwater Fisheries biologist, spent three days sampling creeks around Evergreen as part of a study of the health of the state's waterways. The group caught two dozen species of fish in a two hours in Jordan Creek, which is a few feet across. This bass was one of the largest. (Press-Register/Ben Raines)

CASTLEBERRY, Alabama -- While most anglers would bemoan a day spent catching nothing but tiny fish, the group fishing in a tributary of Murder Creek was ebullient.

Never mind that the biggest fish of the day was a spotted bass not quite three inches long.

The day was dedicated to finding out what lived in Jordan Creek, a task carried out by a team of biologists armed with dip nets, a seine, and an electric fish shocking machine toted in a backpack.

Wearing rubber waders to guard against the jolt delivered by the electroshock machine, which temporarily stuns the fish, the scientists catalogued two dozen species living in a 600-foot stretch of the creek.

There were pirate perch and longear sunfish, a half-dozen kinds of shiners -- including black tailed, black tipped, and longnose -- and a seemingly endless variety of jewel-colored darters.

The darters -- streamlined fish that live in fast-moving riffles -- ranged from the flamboyant speckled darter, which sports alternating bands of turquoise and orange along its flanks, to the bland but rare Choctawhatchee darter, which is the color of sand.

The diversity in these waters mirrors that seen across the rest of Alabama, which has more species of freshwater fish, turtles, snails, mussels and crayfish than any other state.

But that diversity is under siege from a growing list of threats, including subdivisions, logging, industrial pollution, increasing population and agriculture.

Hence the Jordan Creek expedition, more formally known as an index of biotic integrity.

Essentially, the scientists are checking the health of the state’s streams by recording what lives in them, including fish, crawfish, mussels, snails and turtles. The scientists catch fish in 30 locations along each stream, 10 riffle habitats, 10 slow runs, and 10 deeper pools. Then they run the shocking machine along the edges of the creek banks for 250 feet, scooping everything that floats up.

tiny fish 067.jpgThis speckled darter, about an inch and a half long, was one of two dozen species caught in Jordan Creek on Tuesday. Alabama has more species of freshwater fish than any other state, with 345 species. The darters are among the most diverse groups in the state. Some, like this orange and turquoise specimen, glitter like jewels in the water. (Press-Register/Ben Raines)

Most of the fish survive the shocking and capture with no apparent harm.

“Based on the samples, we can determine the biological condition of the stream, whether it is good, fair, poor or excellent,” said Pat O’Neil, director of the ecosystems investigation program for the Geological Survey of Alabama. “It’s a way of boiling down the complex ideas of species presence and abundance, and other factors.”

Streams that end up listed as poor in the ranking system are typically threatened by heavy loads of sediment or agricultural fertilizers flowing into them. Often, the streamside vegetation has been removed, either during logging or farming activities.

For the streams labeled poor, the state plans to focus resources on restoring the habitat, including, in some cases, restocking some of the tiny native species.

O’Neil, like all fish scientists, marvels at the unparalleled diversity in Alabama’s waterways. He said it stems in part from the fact that Alabama simply has more water per square mile of land than any other state.

“Combine that with all the diverse geology and diverse aquatic habitats we have and it leads to diverse fauna,” O’Neil said.

Just as important, O’Neil said, is the fact that Alabama escaped the ravages of the glaciers that scraped across most of what is now the U.S. during the last ice age.

“When you have stable environments that have escaped sea level change and the glaciers, then, with time, we’re talking millions of years, evolution can proceed forward at pretty rapid rates and you get a lot of speciation,” O’Neil said. “That’s what happened in Alabama, particularly in the Mobile River basin. That area has been that way for 200 million years.”

Often, the distinction between some of the state’s hundreds of fish species can be as small as “a speck, or a fleck of color, or a little line” that shows up on one species, but not another, he said.

Wading through the clear streams around Castleberry and Evergreen, most of which feed into Murder Creek, is to step into a world most people in the state never encounter. Dense vegetation overhangs the banks. Limestone outcroppings pockmarked with fist-size holes and riddled with fossils rise up from pebbled stream bottoms.

fish_people.jpgKen Weathers and Pat O'Neil handle a seine net in Jordan Creek, scooping up fish stunned by the electroshock machine on the back of Rob Andress. Jennifer Pritchett, in the center of the picture, scoops up any fish that try to slip past the net. The team of biologists caught two dozen species of fish in the creek, which would be a stunning number of species in any other state. Alabama has more species of freshwater fish, mussels, turtles, snails and crayfish than all other states. (Press-Register/Ben Raines)

Hundreds of snails carpet the algae growing in the fast and shallow riffles, and half-dollar sized turtles sun on logs poking up from the water in the slow runs. In nearby Hunter Creek, which is about three feet wide, the scientists found an old alligator snapping turtle shell large enough for a child to bathe in.

Three teams worked the Murder Creek watershed this week, including scientists from the Geological Survey, the state division of Wildlife and Freshwater Fisheries and the U.S. Fish & Wildlife Service. A total of 25 locations were sampled.

Surprisingly, many of the streams had been invaded by a small clam native to Asia. But for the most part, the waters were rich in native species, including hogchokers, a flounder, and American eels, which journey hundreds of miles, from tiny inland streams to the open ocean, to spawn.

At the end of the day, O’Neil said that Jordan Creek, where the group sampled Tuesday afternoon, was in pretty good shape.

“I would rate this site as fair to good. There were some unique habitats even in this little stream,” O’Neil said. “We’re seeing a lot of that. We have a lot of good, healthy waters.” 


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