The study found Mahoning River sport-fish populations increasing, but bottom-feeding species decreasing.
By PAUL WHEATLEY
VINDICATOR STAFF WRITER
YOUNGSTOWN -- The future of bottom-feeding fish in a local section of the Mahoning River is murky and may be tied to contaminated sediment, according to a recent Youngstown State University study.
Last October, five YSU biology students and YSU professor Nicholas Mandrak crept across the river beneath the Market Street Bridge in a specially equipped motorboat that sent out electric pulses to momentarily stun fish to be captured, inspected and released.
Several species studied: The crew netted the highest number of fish species in more than 100 years of studies here, about 19 in all, over five days on the river.
Statistics were taken on about 497 individual fish -- about 200 more fish than Mandrak originally expected.
However, one bottom-feeding species known as brown bullhead was missing.
In fact, bullhead, which were prevalent in 1988, were also nowhere to be found in a similar 1994 study.
To make things worse, the team found no common carp younger than age 7 last year.
"Either they don't live in the part of the river that we were sampling or there are no young carp," said Mandrak.
Deformities found: Many bottom-feeding fish that were sampled were severely deformed, resembling bug-eyed fish that have been satirized in the syndicated animation series "The Simpsons." Some catfish and carp had split barbels, or whiskers, which is not normal, while other fish had corroded fins or lesions.
"The issue is, the sediments are still there and the contaminants are still there," said Mandrak. "What we're seeing is the fishes that live on the bottom, the benthic fishes, they're the ones that are showing the greatest numbers of deformity, lesions or tumors."
Mandrak's concern is pollutants, such as lubricants, from long-gone river-based factories are causing sterility in bottom-feeders and producing deformities in young that do survive.
His theory is that lubricants ingested are then stored in the fatty areas of fish, such as their ovaries and eggs.
The professor plans to catch Mahoning River bottom-feeders this fall to inspect their organs.
Not all bad news: Results from the study were not completely dire.
The study shows sport-fish populations, such as walleye, bass and bluegill, have risen. Such fish are considered midwater feeders.
Mandrak said the river was likely repopulated from tributaries, which shows the importance of local watersheds.
Yet while some fish numbers may be increasing, the Ohio Department of Health advises people not to consume channel catfish and common carp caught from local sections of the Mahoning River.
White crappie should be consumed only once a week and walleye should be consumed only once a month.