A Somewhat Odd Fish Returns to Ohio

Pirate Perch (Photo by Patrycja Lawryniuk)

The Pirate Perch’s common name, applied by naturalist Charles C. Abbot upon observation that Pirate Perch in his aquarium ate only other fish (actually they also prey on aquatic insects, annelids and crustaceans); is perhaps less accurately descriptive than its scientific nomenclature Aphredoderus sayanus.  The genus Aphredoderus translates to “excrement throat”, referring to the position of the urogenital vent.  It had been speculated that one of Charles Abbot’s naturalist contemporaries (Jacob Gilliams) named the species after the entomologist Thomas Say as a jibe resulting from some acrimony between the two friends, but evaluation of the meaning of the name reveals that “-anus” is used as a suffix that translates to “belonging to” (http://www.etyfish.org/names-of-the-week2014/).

Young Pirate Perch have their vent just in front of the anal fin, but as the fish matures the vent moves forward to just below the juncture of the gills.  Placement of the vent near the throat enables the females to more accurately place their eggs in root masses such as those extending into the water from streamside trees and other woody growth.  As recently as 20 years ago ichthyologists thought that the unusual reproductive morphology supported brooding the eggs in the gills since occasionally females were found with a few eggs therein.  Positioning of the vent is one of the characters (as well as a highly developed lateral line sensory system) shared with cavefishes that is used by ichthyologists to place them in the order Percopsiformes.

The photo below shows a Pirate Perch young-of-the-year (probably about 6 months) with the vent between the pelvic fins at this point in its development.

Pirate Perch young-of-the-year

OSUM 102207 Aphredoderus sayanus adult showing vent under throat (photo by Marc Kibbey)

Pirate Perch were recorded in the Maumee River drainage of northwestern Ohio as far back as 1875 but disappeared over 60 years ago, primarily from destruction of their habitat.  Demand for productive farmland in that fertile area resulted in development of methods to drain the widespread wetlands, including the practice of channelization.  Channelization, or straightening and dredging; of streams was implemented to facilitate accelerated removal of water from areas inundated during heavy rains.  However this method cleared away aquatic plants, logs, sticks and detritus that was the preferred habitat of the Pirate Perch.  Bulldozing the bank sides removed the undercut bank structure with underhanging root masses that sheltered Pirate Perch and multitudes of other aquatic animals.  Removal of streamside riparian barriers results in siltation of stream bottoms mainly from field tillage and exposes aquatic fauna to pesticides and other chemicals; these impacts compounded to extirpate the Pirate Perch from the state.

Pirate Perch are actually rather tolerant of waters with low oxygen content, preferring low gradient, slow moving and fairly turbid oxbows in streams as well as lakes.  Their extensive distribution is not typical for a fish species with exclusive requirements.  Flourishing populations of Pirate Perch can be found just across the Indiana State line as close as the Tippecanoe and Wabash Rivers, where they are frequently found in farm ditches.

Camp Creek Pirate Perch locality (photo by Marc Kibbey)

The last Pirate Perch captured in Ohio was caught in 1950.  Extensive sampling by ichthyologists and agencies in the Maumee River watershed failed to find a Pirate Perch until 2013, when the OSUM Fish Division’s sampling crew of Brian Zimmerman and Justin Baker caught one in the Auglaize River near Waynesfield, Ohio.  Imagine the excitement of the two fish enthusiasts!  At first it was thought that a refuge population had proliferated and reoccupied the former Pirate Perch locality as a result of water quality improvements and habitat re-emergence.  But it turned out that the Ohio Division of Wildlife had released up to 200 individuals near that locality as part of a reintroduction effort back in the early 2000’s.  Subsequent trips to the area found more sites with all size classes (very small young to large adults), particularly in smaller tributary streams like Camp Creek with populations that dominated the fish fauna.

Brian and Justin at Camp Creek (photo by Marc Kibbey)

It appears that current conditions in northeastern Ohio, and particularly the Maumee River watershed, have improved or continue to improve to the point where populations of Pirate Perch can be supported in suitable areas.  Recent implementation of no-till and conservation tillage farming practices reduce siltation of waterways, while these combined with conservation of riparian zones help prevent runoff of pesticides into the streams.  Assuming continuation of these practices as well as sewage treatment and other water quality enhancements, the Pirate Perch should be able to reoccupy former distributions and perhaps even spread beyond their historically known range, reassuming their position among Ohio’s fish fauna.

Other interesting aspects of Pirate Perch’s biology include their color: They are fairly attractive (and make good aquarium pets) with iridescent blue (occasionally green, copper or silver) dots along their olive-to-black back and sides.  The males develop a vivid violet hue that complements their black head and sides in spawning condition.  Additionally Pirate Perch may be the only predator known to exhibit sensiochemical crypsis where they employ a range of olfactory cues to obviate avoidance by a diverse assemblage of prey animals, similar to olfactory mimicry (Resitarits and Binckley, 2013).

Photo by Michael Wolfe

About the Author: Marc Kibbey is Associate Curator of the Fish Division in the Museum of Biological Diversity.