Fishing & Boating Memories Last A Lifetime Pennsylvania Angler & Boater 13

Cruising in the murky waters of west-ern Pennsylvania’s big rivers is one ofthe oldest and largest freshwater fishesof North America. With its long,paddle-shaped snout, grayish-coloredbody, and large tail, this creature lookslike a cross between a swordfish and ashark. But this gentle giant has noteeth and feeds only on zooplanktonand aquatic insect larvae that it filtersfrom the water. In the South, this liv-ing relic is called the spoonbill. Knownas Polyodon spatula to the biologist, thiscreature is the paddlefish.

Paddlefish can live to be 30 or moreyears old. As one of the largest freshwa-ter fishes, paddlefish may grow to sixfeet or more in length and weigh morethan 100 pounds. Paddlefish vary incolor from black to bluish-gray, whichfades to white on the sides and belly.The skin is smooth and nearly scaleless.They have small eyes near the base ofthe rostrum (snout), providing onlypoor vision. The large tail, with the topportion bigger than the bottom por-tion, gives them a shark-like appear-ance. The mouth is large and toothless,but combined with the closely set gillrakers, the mouth makes an effectiveseine to filter the zooplankton onwhich it feeds. The elongated oper-cula (gill covers) allow for expan-sion of the gill openings andmouth while filter-feeding.Another characteristic thatmarks the paddlefish as anancient fish is its skeleton.The skeleton is made en-tirely of cartilage except forthe jaw, which is bone.

The paddle-shaped rostrum,as the snout is properly called, isapproximately one-third the fish’stotal length. Although paddlefish fryare not born with the bill for which theyare named, the rostrum starts growingshortly after birth. Biologists are notsure about the rostrum’s function. Foryears, many people believed wronglythat it was used to dig in the mud. The

Paddlefish Restoration

by Dudley Parr

Progresswith

photo-Craig B

ihrlePaddlefish can live to be

30 or more years old.

As one of the largest freshwater

fishes, paddlefish may grow to six feet

or more in length and weigh more than

100 pounds.

Pennsylvania Angler & Boater Fishing & Boating Memories Last A Lifetime

Early DevelopmentDay 1

Day 3cell division

Day 4heartbeat

Day 5

Day 6larval stage

14

rostrum has many sensory and electro receptorsthat may aid in detecting concentrations ofzooplankton. The rostrum may help balance thefish while swimming with its large mouth open.However, paddlefish that have lost part or all ofthe rostrum seem to suffer no ill effect and socast doubt on its true use.

Paddlefish biologyPaddlefish are found only in North America.

There is only one other species in the Polyodonfamily, which is found in China. Paddlefish arefound in the large, free-flowing rivers of the Mis-sissippi Basin. They prefer backwaters, ox bowlakes, and areas where currents are reduced. Bigislands, bridge pilings, shoals, and sand barsprovide such sheltered areas. Examples of goodpaddlefish habitat in the Three Rivers area arethe confluence of the Beaver and Ohio rivers,around Neville Island in the Ohio, and the is-lands and bridges at the upper end of Pool 2 onthe Allegheny. Although lakes and reservoirscan provide good feeding areas for paddlefish,the dams that create them have inundated suit-able spawning habitat and are barricades topaddlefish during spawning migrations.

Compared to most fish, paddlefish maturelate in life. Males reach sexual maturity at sevento nine years of age, or after about one-fourth oftheir expected life span. Females mature at 10 to12 years of age, or after about one-third of theirexpected life span. Although males may spawn gr

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Paddlefish Polyodon spatula

Rostrum (bill)

paddlefishfrom above

paddlefishfrom below

every year, females require two or more years toproduce up to 10 to 12 pounds of eggs. The eggsare valuable as a source of high-quality caviar.

Until 1960, little was known about paddlefishspawning behavior or habitat requirements. Envi-ronmental conditions have to be just right forspawning to occur. Paddlefish need clean gravelbars with good current flows. The water tempera-ture must be near 60 degrees, the water flows mustbe high and rising, and all of this needs to happenin the spring. A sudden water level rise of six feethas been documented to trigger spawning activity.These environmental factors don’t coincide everyyear. Thus, paddlefish may not spawn every year.

When spawning does occur, it is a simple act. Alarge female, accompanied by a couple of usuallysmaller males, swims over the selected gravel bar.Both sexes release their respective eggs and milt.Fertilization occurs in the water and the eggs be-come sticky. The sticky eggs adhere to the gravelsubstrate so that they don’t wash away. The highwater flow keeps the eggs well-oxygenated andkeeps debris and silt from covering them. In abouta week, the eggs hatch and the larval paddlefishare swept downstream to quieter nursery waters.In a few days, the yolk sac is absorbed and theyoung fish feed first on small insects. Then theybegin their lifelong pursuit of zooplankton.

Young paddlefish are not good swimmers.Their only defense from being eaten is to growlarge fast. It is amazing that the paddlefish canattain its great size feeding only on creatures the

For a few days after hatching,paddlefish fry live off the yolk sac.Once it is absorbed, the fry begin

consuming their lifelong diet ofzooplankton. At this tiny size, paddlefish

pursue individual zooplankton. At this stage,individual zooplankton are enough of a mouthful.

The paddle-shaped bill, for which the fish is named,may aid in balance while feeding and in detectingconcentrations of zooplankton.

EyesSmall, weak eyesight.

Operculum (gill cover)Elongated, swept-back shape helps waterpass through efficiently while filter-feeding.

General- The color of paddlefish varies from almost black to bluish gray, which fades to awhite belly. The tail, triangular dorsal fin, and overall gray color give a shark-like look.The skeleton is all cartilage except for the jaw bone, which can be used to age the fish.

Fishing & Boating Memories Last A Lifetime Pennsylvania Angler & Boater 15

size of the period at the end of this sentence.This means that volume of food is the key topaddlefish survival and growth.

In some states, paddlefish populations arehealthy enough to support active sport fisheries.Because paddlefish feed on microscopic organ-isms, traditional fishing techniques are not suc-cessful. Most anglers catch paddlefish bysnagging. In recent years, a few paddlefish have

been inadvertently “foul-hooked” andreleased by Pennsylvania anglers in theOhio and Allegheny rivers. The paddle-fish season is permanently closed inPennsylvania. The flesh is compared toswordfish in flavor and the roe (eggs) issought for caviar. A recent estimate ofthe value of a pound of processed paddle-fish eggs was $360.

FeedingPaddlefish swim through thewater swinging their mouths

from side to side. Paddlefishstrain zooplankton from the

water through their gill rakers.The rostrum probably serves to

help detect concentrations ofzooplankton and maintain

stability while swimming with itsmouth open.

microscopic view of zooplankton

= historical distribution = restoration project

Lake ErieOhio RiverAllegheny RiverClarion River

Ohio RiverAllegheny River to L/D 6

Range

Heterocercal tailSpinal column curves up intothe upper part of the tail.Triangular dorsal fin.

Pennsylvania Angler & Boater Fishing & Boating Memories Last A Lifetime16

Reintroducing the paddlefishPaddlefish have been swimming in

the large rivers of the Mississippi Basinsince before the dinosaurs. Until theearly 1900s, their range included theOhio, Allegheny, Clarion, andKiskiminetas rivers in Pennsylvania.Paddlefish stocks declined throughoutmuch of their range because of thechannelization of rivers, building dams,and degradation of water quality frompollution. In Pennsylvania, paddlefishare currently classed as extirpated. Thelast documentation of paddlefish inPennsylvania waters was in 1919. To-day, the only paddlefish in Common-wealth waters are those put there by theFish and Boat Commission.

Since 1991, the Commission has beenstocking fingerling paddlefish in theOhio and Allegheny rivers as part of itsPaddlefish Restoration Plan. In the late1980s, a private citizen from the Pitts-burgh area, Mike Koryak, firstsuggested reintroducing extir-pated, native fishes. As indi-cated by the return of manyother fish species, the waterquality in the Three Rivers areahas greatly improved during thelast 35 years. Given the im-proved water quality, the abun-dance of zooplankton, andpresence of appropriate habitat,it seems likely that the paddle-fish could once again take upresidence in Pennsylvania.

After careful study, a plan wasdeveloped with the objective ofrestoring a paddlefish popula-tion to the Ohio and Alleghenyrivers. The female paddlefishtakes 10 years to reach repro-ductive age, so the project willspan at least a decade.

Each May, James E. Harvey, Managerof the Linesville Fish Culture Station,and his staff receive paddlefish fry fromthe U.S. Fish and Wildlife Service inSouth Dakota. Using paddlefish hatch-ery methods developed in Missouri,South Dakota, and Texas, they raise theyoung paddlefish, which grow rapidlyat approximately one inch per week.

In late July, Rick Lorson, Commis-sion Area 8 Fisheries Manager, and hiscrew tag each paddlefish with a tinycoded wire. The coded wire, which indi-cates where and when the fish washatched and stocked, is inserted intothe tip of the rostrum. If the fish islater collected, a tag detector will indi-

About 10 weeks after the eggs are re-ceived, the paddlefish have grown toabout 10 inches and are ready for stock-ing. This usually occurs in early Au-gust. With the help of the localwaterways conservation officers, an av-erage of 10,000 young paddlefish arestocked each year.

So far, no surveys that target paddle-fish have been conducted. The Com-mission is currently seeking a fundingsource for evaluation of the restorationefforts. However, the Fish & Boat Com-mission does have some data on paddle-fish in Pennsylvania. Since 1992 therehave been a total of 12 reported paddle-fish sightings. With each successiveyear, the average size of the fish sightedhas gone up. Six paddlefish were inad-vertently snagged by anglers and re-leased. (Remember, in Pennsylvania,there is no open season on paddlefish.)Three of those paddlefish were cap-

tured during other river studyprojects. Another two paddle-fish were found dead along theshore, and one was spottedswimming below a dam.

Although the sample is toosmall to give an accurate assess-ment, it tells us that there arepaddlefish in Pennsylvania andthey seem to be getting bigger.

The paddlefish predates thedinosaurs and is little changedfrom its ancient ancestors. Thisfact makes paddlefish sensitiveto environmental degradation.The lock and dam system,dredging, and deteriorated wa-ter quality are all manmadeconditions that led to thepaddlefish’s demise in Pennsyl-vania. We have cleaned up our

waters enough for paddlefish to sur-vive. For as much as we take from ourrivers, it is important for us to givesomething back. It is right for us toreturn this great fish to its place in ourwaters. With diligent monitoring ofwater pollution and persistent cleanupefforts, we can continue to improve wa-ter quality for ourselves as well as forthe paddlefish. If the Paddlefish Planproves successful in Pennsylvania, thesturgeon, and other extirpated largeriver species, will be considered for res-toration.

The author thanks Commission Area 8 Fish-eries Manager Rick Lorson for his help inpreparing this article.

cate the presence of the wire tag. Thetag can then be recovered without kill-ing the fish, and the origin of the fishcan be determined. Along with mea-surements of length and weight, know-ing the age and origin is important forevaluating the paddlefish’s comeback.In future years, surveys will be con-ducted to assess the paddlefish popula-tion and the success of the program. to

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Young paddlefish are not good swimmers.Their only defense from being eaten is togrow large fast. It is amazing that thepaddlefish can attain its great size feedingonly on creatures the size of the period atthe end of this sentence.

Commission personnel tag each paddlefishwith a tiny coded wire. The coded wireindicates where and when the fish washatched and stocked. It is inserted into thetip of the rostrum. If the fish is latercollected, a tag detector will indicate thepresence of the wire tag. The tag can thenbe recovered without killing the fish, andthe origin of the fish can be determined.