Basic Training Course Ichthyology

Editors Paul E. Bugas Jr., John R. Copeland, Brian Murphy

Contributing Authors Adrienne Averett, Virginia Department of Environmental Quality Larry Bandolin, U.S. Fish and Wildlife Service, Retired Paul E. Bugas, Jr., Virginia Department of Game and Inland Fisheries John R. Copeland, Virginia Department of Game and Inland Fisheries George Devlin, Virginia Department of Environmental Quality Mike Duncan, Department of Fisheries and Wildlife Sciences, Virginia Tech Charles Gowan, Department of Biology, Randolph-Macon College Scott Herrmann, Virginia Department of Game and Inland Fisheries Dawn Kirk, U.S. Forest Service, George Washington and Jefferson National Forests Brian R. Murphy, Department of Fisheries and Wildlife Sciences, Virginia Tech

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Produced by Virginia Cooperative Extension, Virginia Tech, 2019

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faculty.virginia.edu/afsva-newsletter/ Virginia Master Naturalist Basic Training Course Ichthyology 3

Ichthyology In this chapter, we describe:

• The diversity and distribu- Sandy, and Tennessee. With the exception Introduction tion of fishes in Virginia and of the Rappahannock and York rivers, most Ichthyology is simply the science of study- of Virginia’s river drainages are shared their role in Virginia ecosys- ing fishes. Historically, ichthyologists were with adjacent states. Virginia fishes are not tems. naturalists who described fishes they col- restricted by artificial boundaries, like state lected. Much of our knowledge of Virginia lines, so many of our species are present in fishes resulted from an 1867 sampling trip adjacent states. In general, Virginia’s fish • Key characteristics used to by Edward Drinker Cope. Cope’s contri- diversity increases when moving from the identify fish and basic fish butions to North American vertebrate northeastern to the southwestern corner taxonomy. study earned him the enviable title of of the state. Many fish species are common “Master Naturalist.” His study of Virginia across drainages. Some of these river drain- fishes was followed by those of Marshall ages harbor fish species found nowhere else • The biology and natural McDonald and David Starr Jordan in the but in those areas. These species are known history of fishes, including late 1800s. By 1899, 180 of Virginia’s fish as endemics. The southwestern Virginia adaptations of fish and how species were described. Since 1900, a num- river drainages (the Tennessee, the New, these relate to environmen- ber of ichthyologists, including Robert E. and the Roanoke) have the majority of tal factors. Jenkins of Roanoke College, have brought these endemics. us to our current knowledge of Virginia fishes (for a review of Virginia’s ichthyo- Virginia’s Physiographic Areas • Threats and issues relating to logic history, see Jenkins and Burkhead Virginia has five major physiographic fish in Virginia. 1993). Today, ichthyology is more than areas, from the Appalachian Plateau, describing fish taxonomy and now includes Valley and Ridge, and Blue Ridge in the the study of fish populations, their habitat western third of the state, to the Piedmont • Rare or special species that requirements, and the people who enjoy and Coastal Plain in the eastern two-thirds indicate habitat quality. fisheries resources. Modern ichthyologists, of the state. Each of these physiographic fisheries biologists, and aquatic ecologists areas has underlying geology influencing • Appropriate methods for are employed by government agencies, stream behavior and resulting habitats. private industries, nonprofit organizations, Any discussion of Virginia’s fishes would studying fish. and academia. be incomplete without a consideration of habitats, because fishes are often uniquely • Basic principles of fisheries Diversity and Distribution adapted to their habitat. Virginia’s fish fauna is primarily associated with streams management. of Virginia Fishes and Their and rivers, but a number of species that Role in Virginia Ecosystems inhabit our coastal rivers and bays are able to move between salt and freshwater. Understanding the diversity and distribu- The remarkable array of freshwater fish of 55ºF water, these streams usually stay below 70ºF during the heat of the summer. tion of fishes begins with an understanding in the commonwealth are found from the Mountain streams typically contain few of zoogeography. Unlike terrestrial ani- swampy lowlands of eastern Virginia to the fish species. Some mountain streams drain mals, fish do not move across land without windswept heights of Mount Rogers. Let’s areas with little or no limestone geol- the assistance of flooding or major geologic examine some of these unique environ- ogy, resulting in low pH values from acid events that result in stream capture. To ments and how fish have adapted to them. understand fish distribution, you must first precipitation. know river drainages and physiographic Mountain Streams Virginia’s mountain streams typically areas, since these features influence fish The western third of Virginia supports contain brook trout (Salvelinus fontinalis) distribution. over 2,000 miles of cold-water mountain and blacknose dace (Rhinichthys atratulus), streams along forested, high-gradient a member of the minnow (Cyprinidae) Virginia’s River Drainages slopes where ground water comes to the family. Brook trout are excellent swim- Virginia contains 10 major river drainages; surface as springs. Mountain streams typi- mers and are able to recolonize mountain the Potomac, Rappahannock, York, James, cally have bedrock or boulder beds. With streams after devastating floods and severe Chowan, Roanoke, PeeDee, New, Big adequate shading and a constant supply

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droughts. They are the top predators in requiring fish species adapted to these dark (Perca flavescens), are known for their an- these streams. Brook trout only exist in stained waters. nual spawning runs up these tidal rivers highly oxygenated, cold, flowing water. from the Chesapeake Bay into fresh water. They need loose, clean gravel to build nests The dominant fish in our warm-water These species sustained Native Americans and rely on the macroinvertebrate life in streams are in the family Cyprinidae. Rep- and early colonists. Commercial harvest those gravels as a source of food. A brook resentatives from this family are known of anadromous fish continues today in trout’s body is streamlined for swift move- by many names, such as minnows, dace, our estuaries and is a significant economic ment in pursuit of food and for stabiliza- chubs, and shiners. Although most are asset. The backwaters of our tidal riv- tion in swift water. Brook trout, Virginia’s small, the large, introduced common carp ers serve as nursery areas for young fish. only native trout, were a food staple of (Cyprinus carpio) can reach lengths of 30 Resident fish species, like largemouth bass Native Americans and early pioneers. Blac- inches. What members of this family lack (Micropterus salmoides) and introduced knose dace often swim in schools among in stature, they make up in numbers and blue catfish Ictalurus( furcatus), can tolerate the quiet eddies of mountain streams. species. Cyprinids comprise the largest fish the brackish waters of the Chesapeake They are an important food item for brook family in the world (approximately 2,400 Bay, and are a draw for professional fishing trout and are a good indicator species of members) and in Virginia (67 species). tournaments and catfish anglers in search pollution from acid precipitation. Many Cyprinids group together in large of world records. The rare Atlantic stur- schools, thus serving as an important geon (Acipenser oxyrhynchus), known for As these streams leave their high-gradient food base for top-level predators. Others, its huge size as an adult, was once highly headwaters, water temperatures rise, food like the river chub (Nocomis micropogon), prized for its roe. items increase, and habitat changes invite are wonderful architects, building large, a greater diversity of fish species. Sculpins complex nest structures used by multiple Caves and Swamps (family Cottidae), darters (family Percidae), fish species for spawning. Numerous Although western Virginia has dozens of shiners (family Cyprinidae), and suckers (fam- suckers are found in warm-water streams. caves within its karst topography, cave- ily Catostomidae) are often integrated with They serve as the fish version of vacuum fish (familyAmblyopsidae ) do not exist in trout populations below 1,000 feet elevation. cleaners, gaining nutrition from eating Virginia’s underground streams. Cavefish Sculpins are small fish with a depressed body aquatic insects, crustaceans, and mollusks, are present in the lower Tennessee River shape, huge pectoral fins, and a reduced air as they “vacuum” detritus from pools and drainage in Tennessee, Alabama, and Ken- bladder. These features allow them to hug eddies. Some people still “dip” for suckers tucky, but are absent in Virginia. A close the stream bottom, where they feed on small during spring spawning runs for canning cousin, the tiny swampfish Chologaster( cor- insects and, occasionally, fish eggs. purposes or for their roe. Colorful darters, nutus), has reduced eyes and a specialized members of the perch family, are endemic sensory apparatus on its snout to live in the Warm-water Streams to North America. In Virginia, the major- darkly stained, acid waters of southeastern The commonwealth’s warm-water streams ity of the darters occur in the Tennessee Virginia. include 25,000 miles of fishable resources. River drainage in the southwestern portion They dominate the Piedmont, Coastal of the state. Darters live on the stream Lakes, Ponds, and Reservoirs bottom in fast flowing habitats, such as Plain, and much of the Valley and Ridge Virginia has only two natural lakes; Moun- runs and riffles. Like sculpins, darters are provinces. Warm-water streams typically tain Lake, a lake in Giles County created bottom dwellers that serve as an ecologi- reach summer water temperatures over by a landslide, and Lake Drummond, a cal link between macroinvertebrates and 70ºF and are home to most of the fresh- basin in the Dismal Swamp in southeast- predators. Because darters are only found water finfish and shellfish in the state. ern Virginia. Virginia’s streams and rivers in the cleanest rivers and streams, they are Streams in the Valley and Ridge prov- have been dammed for generating power, excellent indicators of good water quality. ince are typically medium gradient, with controlling flooding, and providing recre- bedrock, boulder, and cobble bottoms. ation. Reservoirs are especially devastating Streams in the Piedmont are medium- to Tidal Rivers to some species of freshwater mussels and low-gradient systems with boulder, cobble, The Potomac, Rappahannock, York, fish that prefer flowing water. Because res- gravel, and sand bottom composition. James, Meherrin (Chowan River drainage), ervoirs are artificial systems, they are often Many Piedmont streams support diverse Nottoway (Chowan River drainage), and stocked with a variety of nonindigenous fish communities due to near-normal pH Roanoke rivers all have a fall line, the break sport fish. Largemouth bass, bluegill (Lepo- values, varied habitats, and warm water between the Coastal Plain and Piedmont mis macrochirus), black crappie (Pomoxis temperatures. Coastal Plain streams are provinces. Downstream from the rocky nigromaculatus), channel catfish Ictalurus( low-gradient sand and silt systems with an fall line, these rivers are influenced by tides punctatus), walleye (Sander vitreum), brown abundance of woody debris and aquatic and salt. Anadromous fish, represented trout (Salmo trutta), rainbow trout (Oncho- plants on the fringes. Many coastal plain by striped bass (Morone saxatilus), herring rhynchus mykiss), and striped bass are pres- streams have low pH values, due to tannic and shad (family Clupeidae), white perch ent in Virginia impoundments, depending acids, and low dissolved oxygen levels, thus (Morone americana) and yellow perch on whether their habitat requirements are

2019 • Publication 465-312(CNRE-73P) Virginia Master Naturalist Basic Training Course Ichthyology 5 met. “Baitfish” are often introduced to sup- of those families in your area of the state. Body proportion is the measurement of a port these hungry predators. Stocked bait- Virginia’s fish fauna is comprised of fish fish’s length with regards to its depth. An fish include blueback herring Alosa( aesti- from 24 families. The most numerous elongated body shape has a small depth in valis), alewife (Alosa pseudoharengus), and family is the minnows, which contains comparison to its body length. A prime ex- threadfin shad Dorosoma( pentenense). The 67 Virginia fish species. Virginia’s next ample of an elongated body design would gizzard shad (Dorosoma cepedianum) is an most diverse family is the perches, which be the chain pickerel (Esox niger). A deep unwanted, but often inadvertently stocked contains 45 Virginia fish species, from the body shape has a depth measurement that pelagic baitfish. Gizzard shad grow rapidly small stream-dwelling darters to walleye, is large when compared to the body length. to large sizes (> 12 inches), making them a prized sport fish. Other notable diverse Adult specimens of bluegill have a deep unavailable for young piscivores. All these Virginia fish families are: the suckers with body shape. baitfish are outfitted with long, slender gill 18 native species; the catfishes with 15 spe- rakers. They feed by swimming with their cies, from the large flathead catfish to the Description of mouth position helps with mouths open, straining plankton from the small stream-dwelling madtoms and ston- some identification characteristics. Fish open water. Because they feed on the base ecats; and the sunfishes with 19 species, with a terminal mouth have jaws that of the reservoir food chain, baitfish are an many of which are prized game fishes, like are relatively even in length and meet at a important ecological link in reservoirs. the largemouth bass and the smallmouth point at the tip of the head (Figure 12-5). bass (Micropterus dolomieui), the black A largemouth bass is a prime example of Economic Importance crappie, and the bluegill. a fish with a terminal mouth. Fish with a of Virginia Fishes superior mouth have a lower jaw project- Some members of the catfish Ictaluridae( ), Key Characteristics ing beyond the upper jaw. Certain Clupeids, like hickory shad (Alosa mediocris) have sunfish Centrarchidae( ) (which includes Used to Identify Fish bass and “bream”), eel (Anguillidae), and a slight superior alignment of their jaws. pike families (Esocidae) are sought by The key characteristics used to identify An inferior mouth is one with an opening recreational and commercial fishermen be- fish rely heavily upon the presence or under the head, with the upper jaw pro- cause they represent the top of the aquatic absence of exterior features (Figures 12-1 truding well out in front of the lower jaw. food pyramid. Their economic importance and 12-2). Body shape and specific traits Members of the sucker family have an in- to Virginia is reflected in the number of also assist in distinguishing the identity of ferior mouth, making them natural bottom fishing licenses sold annually (858,000 many fish species. A summary of general feeders. Fish with subterminal mouths resident and 218,000 nonresident in 2006) traits is included in this section. The main have an upper jaw reaching slightly beyond and the economic impact of recreational areas of description begin with the head, the lower jaw. Members of the catfish freshwater fishing in the state (an estimat- body, and tail. The head region is located family have subterminal mouths, allowing ed $809 million in total economic output, from the tips of the jaws to the outside them to feed heavily upon the bottom for creating 9,213 jobs, which generate almost edge of the operculum. The body region prey items. $250 million in earnings) (American continues from the operculum to the Sportfishing Association, 2008). base of the caudal fin. The side of a fish is Fin description and the location of fins are defined as thelateral region. Thedorsal additional key characteristics that aid in Virginia’s Fish Diversity region refers to the back or top of the fish. fish identification (Figure 12-3). Fish have three unpaired fins that can be used for North America has the most diverse temper- Theventral region is located along the bot- identification purposes. The caudal fin is ate freshwater fish diversity in the world, tom or underside of the fish. The anterior used to identify a variety of fish families. A with nearly 800 native fish species inhabiting region describes the front of the fish while waters of the United States and Canada. The the posterior refers to areas located near prime example is the heterocercal caudal southeastern United States is the geographic the rear. fin of sturgeon (familyAcipenseridae ) and center of North American fish diversity, with paddlefish (familyPolyodontidae ). Other over 600 native fish species. Southeastern The main types of body shape arefusi - types of caudal fins are displayed below states with the richest described freshwater form, tapering, rectangular, oval (disk- (Figure 12-3). Thedorsal fin is a median fish species diversity include Tennessee shaped), and eel-like (Figure 12-4). A fish fin that runs down the center of the dorsal (307), Kentucky (242), Alabama (257), with a fusiform body shape is streamlined, region. The dorsal fin can be supported by Georgia (219), and Virginia (217). with tapering edges at both ends, while a specific series ofspines or fin rays. Dor- a fish with a tapering body shape has sal fins come in variety of shapes and sizes, Describing Virginia’s diverse fish species narrowing depth near the tail. A fish with from the long, undulating dorsal fin of the is best left up to ichthyologists and other a rectangular body shape has a quick nar- bowfin (Amia calva) to the sharp-spined fisheries science professionals. A good first rowing adjacent to the caudal peduncle. dorsal fin of a white perch. Theanal fin is step for Master Naturalists is to learn Vir- Fish with an oval or disk shaped body a median fin that runs along the midline of ginia’s major fish families. Then, become are more of a rounded shape. An eel-like the ventral region, near the anus. The anal familiar with some of the representatives fish has a long, serpentine body shape. fin can be supported by numerous spines

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or soft fin rays. Some fish families, like the that are located on the both sides of the the abdomen. Theadipose fin is a fleshy eels (family Anguillidae), can be easily iden- body of most freshwater fish. Pectoral fins fin located between the dorsal and caudal tified by the presence of a dorsal fin that are positioned behind the operculum (gill fins of catfish and trout and salmon (family is joined with the caudal fin and the anal plate). Pelvic fins are in the ventral region Salmonidae) (Figure 12-1). fin.Pectoral and pelvic fins are paired fins with various positions from the throat to

Figure 12-1. Internal and External Features of Soft-Rayed Fish (based on illustration by Scott Herrmann)

Figure 12-2. Internal and External Features of Spiny-Rayed Fish (based on illustration by Scott Herrmann)

Figure 12-3. Caudal (Tail) Fin Shapes (based on illustration by Scott Herrmann)

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The presence, or in some cases, the absence Caudal fin type is used when defining of scales, helps to identify some fish species other fish families. A heterocercal cau- and fish families. A prime example of a dal fin is seen in the paddlefishes (fam- fish lacking scales is the catfish. Scale types ily Polyodontidae) and sturgeons (family can also be used in identification.Cycloid Acipenseridae). The paddlefish,Polyodon scales have smooth regions exposed, which spathula, is known from the Clinch and makes for a body that is soft to the touch. Powell River drainages of Virginia. It is Trout and salmon have cycloid scales. identified by its large, paddle-shaped snout Ctenoid scales have spiny exposed edges that give fish a rough feel. Ctenoid scales and long opercular flap. TheAcipenseridae can be easily felt by anyone who has ever family is distinguished by rows of large handled a yellow perch ( ). bony plates or scutes along the length of Perca flavescens The next taxonomic divergence involves Ganoid scales are similar to a thick coat the body. Additional defining character- the presence or absence of pelvic fins. The of scaled armor. These interlocking scales istics include a ventral mouth and barbels absence of pelvic fins is a characteristic of provide a protective layer for the gars (fam- along the underside of the snout. The the eels (family Anguillidae) and cavefishes ily ). Lepisosteidae Atlantic sturgeon (Acipenser oxyrhynchus) (family Amblyopsidae). TheAnguillidae is found in multiple Virginia river systems family is represented by the American Fish have other specific features that allow while the very rare shortnose sturgeon eel (Anguilla rostrata). Thiscatadromous for easy identification. The longnose gar (Acipenser brevirostrum) has only been species has a serpentine body shape with (Lepisosteus osseus) has long, beak-like jaws continuous dorsal, caudal, and anal fins. full of teeth. Catfish have chin barbels. found in Potomac River. The familyAmblyopsidae has one species Sticklebacks (family Gasterosteidae) have in Virginia, the swampfish Chologaster( long dorsal spines. Fish families are identi- cornuta). The swampfish differs from the fied primarily by the features described in American eel because its dorsal, caudal, the Fish Taxonomy section. The identifica- and anal fins are separated. Swampfish are tion to a certain species within a large fish a small (1 to 2 inches long), nocturnal spe- family takes a lot more patience. Specific cies found in backwaters of the Nottoway characteristics of spine and fin ray counts, and Blackwater Rivers. scale patterns, scale numbers, jaw structure, body coloration, and pigmentation all can be used for further identification.

Fish Taxonomy Taxonomy is the scientific classification Two fish families with an abbreviated of organisms into an ordered system of heterocercal caudal fin are the gars (fam- groups. Virginia has 217 fish species from ily Lepisosteidae) and the bowfin (family 24 taxonomic families. A picture-based Amiidae). Defining characteristics of the taxonomic key can be used to identify fish Lepisosteidae family are their long, beaklike to family. jaws lined with sharp teeth. Their dorsal fin is located toward their posterior end The absence of paired fins and jaws and The next taxonomic split is the presence or the presence of seven external gill openings and their body is covered with thick ganoid absence of an adipose fin. Three families describe the primitive fish called lampreys scales. Longnose gar (Lepisosteus osseus), have an adipose fin: bullhead catfishesIc ( - (family Petromyzontidae). All other fish found in large rivers and some reservoirs, is taluridae), salmon and trout (Salmonidae), families have a least one set of paired fins the only gar species in Virginia. and trout perches (Percopsidae). Multiple and one external gill opening per body side. families are distinguished by the lack of an ThePetromyzontidae family has 6 species TheAmiidae family is represented by the adipose fin. in Virginia, with parasitic forms like the bowfin (Amia calva). Bowfins have a long The family consists of species sea lamprey (Petromyzon marinus), as well undulating dorsal fin and jaws of normal Ictaluridae with barbels present above and below as nonparasitic forms like the American length. The bowfin body is covered with the mouth and no scales on the body. In brook lamprey (Lampetra appendix). cycloid scales and has a bony (gular) plate Virginia, there are 15 species of catfishes under the lower jaw. Bowfins are native to in four genera. In the genus Ictalurus, the Coastal Plain and the lower Piedmont. there are two species of forktail catfishes, They have been introduced to the Roanoke the blue catfish Ictalurus( furcatus) and and New River drainages. the channel catfish Ictalurus( punctatus).

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The genusPylodictis has one species, the The family Clupeidae has a laterally com- flathead catfish (Pylodictis olivaris). Ameiu- pressed (keel-like) body with sharp-edged rus (bullheads), a group of medium-size imbricated scutes. American shad (Alosa catfishes with large heads, has six species. sapidissima), hickory shad (Alosa medi- The genusNoturus , small catfishes known ocris), alewife, and blueback herring are as madtoms, accounts for six species in anadromous, so they are primarily found Virginia. Species in the Notorus genus in Virginia’s coastal rivers. Gizzard shad have adipose fins with the posterior edge are widespread through multiple large river attached to the caudal fin. systems and reservoirs. Threadfin shad (Dorosoma petenense) have been stocked in If the anus is located in front of the anal some Virginia reservoirs as prey fish, but in fin, posterior to the base of the pelvic fin, it our cold winter climate, they frequently die fits into one of 12 remaining Virginia fish due to temperature shock. families. Five of these fish families have one dorsal fin and less than four dorsal fin spines. These five families are distin- guished by the shape of their caudal fin. A forked caudal fin describes species from the Cyprinidae (Minnow) and Catostomidae (Sucker) families.

TheCyprinidae family, the largest verte- brate family in the world, is also the largest fish family in Virginia with 67 species, The familySalmonidae has cycloid scales The remaining fish families have bodies including several state threatened species. on the body and fins without spines. Three that are not keel-like. If the snout is shaped Carp (Cyprinus carpio), shiners (multiple species of Salmonidae, brook trout, brown like a duck bill, the species belongs to the genera), chubs (multiple genera), and trout, and rainbow trout are present in Esocidae family. Chain pickerel is the most goldfish (Carassius auratus) are members mountain streams and some reservoirs in abundant representative of this family. of this family. Specific traits ofCyprinids the western third of the state where they Redfin pickerel (Esox americanus), the include dorsal fins with nine or fewer rays, are premier game fish for anglers. The smallest Esocid, is found in small streams 17 branched caudal rays, and pharyngeal brook trout is the only native representa- in the Coastal Plain. Northern pike (Esox arches with six or fewer teeth. tive of this family in Virginia. lucius) are a nonindigenous species stocked in a few Virginia reservoirs where they do not reproduce naturally. Muskellunge (Esox masquinongy) is the prized trophy game fish of this family. This nonindig- enous sport fish is stocked in several rivers and reservoirs to provide trophy fishing opportunities. Some populations are natu- rally reproducing in areas where they were originally stocked. The familyPercopsidae is represented by one species, the eastern trout perch (Per- copsis omiscomaycus). This species was pre- viously found only in the upper Potomac The family is represented River drainage, but is now considered ex- Catostomidae by 18 species in Virginia. Distinguishing tirpated from Virginia. The eastern trout characteristics include dorsal fins with 10 perch has two weak spines in the dorsal fin, or more rays, 16 branched caudal rays, and one weak spine in the pelvic and anal fins, a Families without a duckbilled snout are pharyngeal arches with 10 or more teeth. large dorsal fin, and an unscaled head. distinguished by the position of their anus. Catostomids inhabit many river systems If the anus is located immediately behind across the state. The creek chubsucker Er( - the head and in front of the pelvic fin base, imyzon oblongus) and northern hogsucker the fish belongs to theAphredoderidae (Hypentelium nigricans) are two abundant family (pirate perches). The only species in species from this family. this family, the pirate perch (Aphredoderus sayanus), inhabits the darkly stained waters of the Coastal Plain and central Piedmont.

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The remaining fish families all have scaled bodies and pelvic fins with five or more rays. The number of anal spines separates these families. The familiesMoronidae (striped basses) and Centrarchidae (sun- fishes and basses) have anal fins with three or more spines.

The last main assemblage of fish fami- TheMoronidae family has the first and lies are defined by the presence of two second dorsal fins narrowly separated or dorsal fins. TheGasterosteidae family slightly conjoined and they have pseudo- (sticklebacks) has a pelvic fin with a single branchae. Four North American species prominent spine and the first dorsal fin of Moronidae live in freshwater and marine has widely separated spines with a separate habitats where they are sought as sport fish membrane for each spine. Three species of by anglers. Three of these species are found The remaining three families (from the sticklebacks are found in Virginia. in Virginia. Striped bass (Morone saxatilis) group mentioned above with one dorsal inhabit coastal rivers and some reservoirs fin and fewer than four dorsal fin spines) (where they are typically maintained have one dorsal fin and a rounded caudal with annual stocking). Virginia is one of fin. They are theUmbridae (mudminnow), a few states with a naturally reproducing Fundulidae (killifishes), andPoeciliidae reservoir striped bass population in Kerr (livebearers) families. Reservoir (also known as Bugg’s Island Lake). White perch (Morone americana) TheUmbridae family consists of one are found in coastal rivers and some species, the eastern mudminnow (Umbra reservoirs, since they can live in a variety of ) that inhabits waters of the lower pygmaea All other Virginia fish families lack a pelvic habitats. White bass (Morone chrysops) are Piedmont and Coastal Plain. A character- spine. Fish with pelvic fins in an abdominal more numerous in southwestern Virginia istic of the mudminnow family is the lack position that have well separated dorsal rivers, but a few populations are found in of a protractible mouth. The upper jaw is fins are members of theAtherinidae family Virginia reservoirs, including Kerr, Claytor, attached to the snout by a wide bridge of (silversides). The brook silverside Labides( - and Holston. tissue known as the frenum. thes sicculus), which inhabits the Clinch and Powell rivers, is the only species of this family found in Virginia.

TheFundulidae (not pictured here) and Po- eciliidae families have similar body forms, and both of them have extensible mouths. Representatives of the Cottidae family TheCentrarchidae family has their first and TheFundulidae family has a distinguish- (sculpins) have three to four rays in their second dorsal fins moderately or broadly able branched third anal ray with the pelvic fins, which are located in athoracic conjoined and they do not have psue- same shape in both sexes. Five species of position, and an unscaled body. There dobranchae. Nineteen species from the killifishes have been collected in Virginia. are nine species of sculpins in Virginia, Centrarchid family inhabit Virginia waters. The banded killifishFundulus ( diaphanous) primarily in the western mountain streams. This diverse family contains many popular is abundant in coastal river systems and The mottled sculpin Cottus( bairdi) is the sport fish species. The genusAmbloplites limited populations are found in mountain most widespread species in this family in contains the rock bass (A. rupestris) and streams. ThePoeciliidae family has a third Virginia. the Roanoke bass (A. cavifrons). The genus anal fin ray that is not branched. Males Pomoxis consists of the popular sport fish have an anal fin ray that is modified into species black crappie (P. nigromaculatus) an intromittent organ that assists with and white crappie (P. annularis). The genus livebearer reproduction. A representative Enneacanthus (banded sunfishes) consists of this family, the eastern mosquitofish of three species, including the black- (Gambusia holbrooki), is found in numer- banded sunfish (Enneacanthus chaetodon), ous waters statewide, primarily due to its a state endangered species found in some introduction for mosquito control. southeastern Virginia ponds. The genus

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Micropterus consists of the very popular (S. canadense), which are only found in the sport fish often called black basses: the Clinch and Powell rivers in southwest Vir- largemouth bass, smallmouth bass, and ginia. The genusPercina is represented by spotted bass (M. punctulatus). The genus 15 species of darters in Virginia, including Lepomis consists of seven sunfish species the state and federal endangered Roanoke with the bluegill being one of the most logperch (Percina rex). The genusEtheosto - popular sport fish species in this genus. ma is represented by 26 species of darters, including a number of state threatened and endangered species. The genusAmmocryp - ta is represented by the state threatened western sand darter (A. clara), an inhabit- Adaptations, Biology, and ant of the upper Tennessee River drainage. Natural History of Fishes Body shape Fish have various physical and behavioral adaptations that help them survive in specific habitats and make them efficient and successful competitors. One obvious adaptation is body form or shape (Figure 12-4.), which can tell us a great deal about where and how a fish lives. Fast-swimming, open-water fishes are streamlined and elliptical in cross-section, or fusiform. An The familiesPercidae (perches) and Sci- example of a fusiform shaped fish from aendiae (drums) have anal fins with one to Virginia is the brook trout. Fishes that are two spines. ThePercidae family is a large TheSciaenidae family has a specific charac- not constantly moving, but are capable of family, boasting 176 species worldwide, teristic of a second anal spine that is broad short bursts of speed are more laterally with 92 percent of those found in North and long and a lateral line extending onto compressed, and called compressiform. A America. Virginia has an abundant Percid the caudal fin. The males have the ability to good example of compressiform shaped family, with 45 species found here. The make a drumming noise to attract a mate. fish are sunfish of theCentrarchidae family. genus Perca is represented by yellow perch In this family, only the freshwater drum Fish that are flattened dorsoventrally, such (P. flavescens), found in coastal rivers and (Aplodinotus grunniens) inhabits Virginia as skates, are termed depressiform, which some Virginia reservoirs. The genusSander waters. Their range is primarily concentrat- suits them for life on the bottom. Other includes the popular sport-fish species ed in the Clinch and Powell river systems, fish that live on the bottom and are flat- walleye, found in multiple Virginia rivers with an introduced population in Kerr tened on their ventral side include sculpins and reservoirs, and the lesser known sauger Reservoir. and catfish.

Figure 12-4. Fish body shapes (from Jenkins and Burkhead 1993).

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Fins tend to have terminal mouths with devel- habitat, such as the chain pickerel, gener- In addition to body shape, fins also vary ac- oped rows of teeth. Subterminal mouths are ally have vertical bars or large, circular cording to the fish’s way of life. The caudal fin made for shoveling along the bottom surface color patterns. Most fish, but especially (or tail) is especially telling. Those fish that for prey items (catfish). Many predatory those that live in open water, are dark col- swim rapidly and are constantly on the move fishes, such as the largemouth bass, have ored on the dorsal surface and light colored generally have a forked or crescent-shaped rows of teeth in broad pads both in the on the ventral surface to provide camou- caudal fin. Species with truncate, rounded, mouth and on the pharyngeal bones to flage when they are viewed from above and or emarginate caudal fins may be strong catch and hold prey and aid in swallowing. below. Many fish exert some control over swimmers but somewhat slower than those The central stoneroller Campostoma( anom- their color, becoming paler on pale-colored with forked tails. Fishes with small caudals alum), a grazing minnow, has a hard ridge backgrounds, and vice versa, within a time or those continuous with the dorsal fin tend on the lower jaw to scrape algae from rocks. frame of two to three minutes. to be weak swimmers, and move along the Herbivorous or detritus-eating fishes have bottom. Benthic dwelling fish, however, have relatively long, coiled intestines, often many Swimming times the length of their body. Carnivorous other advantageous adaptations. For example, The most obvious thing about a fish is that fishes generally have short intestines, while the position of the paired pectoral and pelvic it can swim. What is not obvious is how it omnivorous fishes have guts of intermediate fins in sculpins and darters creates a friction moves through the water with what seems length. A longer gut increases the surface plate (a rough surface) that helps them hold so little effort. Aristotle first asked this area and allows for more time for absorption their place among rocks. The fleshy adipose question, but it was not until the advent of nutrients. fin has little function, but is found on trout, of high-speed film that good answers were trout perch and catfish. obtained. The simple story is that the fish Color flexes its body into an undulating “S” shape, Mouth Coloration is another important adapta- pushing against the surrounding water to Mouth shape and placement provide clues tion of fish to their environment. Fish generate thrust. Some fish, such as eels, in- about how a fish feeds and what it eats living on sand, such as the western sand volve their entire body in the process, while (Figure 12-5.). Surface feeders, such as darter, are a pale translucent color. Fish others, such as tuna, use just the tail area. topminnows, possess a superior mouth, living on stony substrates are either a dark whereas bottom feeders, such as suckers and color or boldly mottled, so they blend into The flexing is generated by muscles called some darters, will have the mouth oriented the background. The mottled sculpin is myomeres that occur in vertical bands downward (inferior mouth). Top predators a good example. Fish living in vegetated along the fish’s body (Figure 12-6.). When

Figure 12-5. Mouth positions (from Jenkins and Burkhead 1993)

Figure 12-6. Fish myomeres

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you use a fork to flake a fish filet, you are A fish’s ability to swim efficiently is also All fish more advanced than the lampreys separating the myomeres. The myomeres due to its capacity to maintain neutral take water in through their mouths and contract in sequence from head to tail, buoyancy in the water (neither sinking nor force it out through the gill opening. This alternating on each side of the body in per- floating). To do this, a fish must perfectly eliminates the need to pump water in and fect sequence to generate the “S” shape. It is match its density to the density of the sur- out of the gill chamber, greatly reduc- an incredibly efficient way to move through rounding water. The complication is that ing the energy the fish must devote to water. Using this swimming mechanism, a water density changes with depth and tem- breathing. The second major advance was 1,500 pound tuna (family Scombridae) can perature, and so the fish must be able to that fewer openings were needed. A few reach speeds of 50 miles per hour and a precisely adjust the density of its own body very-ancient sharks have seven gill slits just steelhead trout (Oncorhynchus mykiss) can on an almost continuous basis. How? Most like the lamprey, but modern sharks have leap more than 15 feet straight up out of fish use a specialized organ called theswim only five. Even more advanced fish, such as the water. bladder (Figure 12-1). This gas-filled blad- trout, minnows, and bass have just one gill der lines the top of the body cavity, and a opening per side, covered by a flap called In most fish, the fins are not used to gener- fish can pump gas into and out of it in or- the operculum. Inside the operculum are ate thrust (except for the tail), but instead der to adjust its overall body density, much four bony gill arches, each holding a set of are used as stabilizers, rudders, and brakes. like scuba divers adjust their density using gill filaments (Figure 12-2). You can see The body generates the speed, and the fins a buoyancy compensation device. Working the white gill arches when you look down provide maneuverability. If you watch a fish together, the body, fins, and swim bladder the throat of a fish, and you can see the red carefully, you will see that it has very pre- allow a fish to move quickly and accurately gill filaments when you lift the operculum. cise control of each of its fins. This control through water, a substance which is 780 The gill filaments are red because they is due to rays and spines. All fish have rays times more dense than air. are filled with oxygenated blood, which is in their fins, and more evolutionarily-ad- pumped around the body by the heart. The vanced ones also have spines. Fish raise and Breathing gill arches often have spines on them called lower their fins by controlling the rays or Fish use gills to take in oxygen from the gill rakers to prevent food from escaping spines. Each ray or spine is connected to a surrounding water and release carbon out the gill opening. bone called a pterygiophore (pronounced, dioxide. In ancient fish, such as lampreys, “ter-ridge-e-o-four”), which is embedded there are seven openings along each side Osmoregulation in the myomeres but not connected to the of the body, each leading to a blind sac One of the most important physiologi- rest of the skeleton. By flexing the myo- (the gill chamber) lined with gill tissue. cal adjustments that fish make involves meres, the fish can pull the pterygiophores Muscles around each gill chamber contract osmoregulation, or the maintenance of forward to lower the fins or backward to to squeeze water out like a balloon, and proper water and salt balance in their tis- raise them. This fine-tuned mechanism then relax to allow new water to flow in. sues (Figure 12-7) Because a fish’s internal allows the fish to independently control As fish evolved more efficient respiratory salt concentration is usually different from each fin, providing very precise control over systems, two major advances were made. the water in which it swims, it must be movement. The first was the “flow through” system. able to prevent excessive gain or loss of

Figure 12-7. Osmoregulation in freshwater and saltwater fish. In freshwater fish, such as striped bass when they move into rivers, salts (ions) flow out of the body through a process called diffusion. Diffusion is when ions flow from an area of higher concentration to an area of lower concentration. Freshwater fish make up their ion loss by taking them from the water. In saltwater fish, such as striped bass when they are in the ocean, ions flow into the body. Saltwater fish constantly remove ions from their bodies. In both cases, water flows in the opposite direction from ions.

2019 • Publication 465-312(CNRE-73P) Virginia Master Naturalist Basic Training Course Ichthyology 13 water. The body fluids of freshwater fish they make the transition from saltwater to catfish, and suckers, a series of small bones have a higher salt concentration than the fresh when returning to spawn, and then connect the air bladder with the inner ear. surrounding freshwater, while marine spe- again as they return to the ocean. This is This is called theWeberian apparatus and cies have more dilute body fluids than the particularly difficult for the newly-hatched its purpose is to convey pressure changes in sea water around them. Osmoregulation is juvenile fish making their way to sea for the air bladder with sound. accomplished by the kidney, the gills, some the first time. One reason why estuaries, special organs, and to some extent, by the such as Chesapeake Bay, are so important Touch: Fish possess a system of sensing body covering (skin and scales) in its role for migrating fish is because they provide a touch called the lateral line system that is as a barrier. Fishes that live in both fresh gradual transition from fresh to saltwater, truly unique (Figures 12-1 and 12-2). The and saltwater at some point in their life allowing the fish’s metabolism to adjust to lateral line system is a hollow canal run- cycle, for example, shad or American eels, the new conditions. ning just under the scales from head to tail must adjust their osmoregulatory mecha- along each side of the fish, about half-way nisms accordingly. Aquatic organisms Senses down the side of the body. A special row devote more attention to osmoregulation Fish have the same five senses humans of scales covers the lateral line, each with than terrestrial ones because diffusion of possess (sight, hearing, touch, smell, and a small opening (the pore) connected to salts to and from the surrounding water is taste). Anglers are often well informed the lateral line canal by a tube. If you look constantly occurring, pushing the fish out about fish sensory systems, but they are closely at a fish, you can see the pores that of osmotic balance. often a mystery to other people. Can fish form a single row of white dots along each detect color? What’s the purpose of catfish side. These pores connect the lateral line Freshwater and saltwater fish face exactly “whiskers”? How can schooling fish move canal to the outside world. Any pressure opposite challenges regarding osmoregula- in unison? Let’s examine how freshwater wave sent by nearby objects is picked up tion. Freshwater fish arehyperosmotic , fish detect food, swim from danger, or find by the lateral line and a signal is sent to the meaning that the desired salt concentra- a place to spawn. brain. One spectacular way the lateral line tion of their tissues is higher than that of is used is to coordinate the movements of the surrounding water. Because substances Sight: The role a fish species fills in nature fish in schools. If you watch a school of fish always diffuse from higher concentrations often reflects the degree of vision the ani- closely, you will be amazed at how perfectly to lower ones, salt is constantly trying to dif- mal possesses. For instance, large predators they coordinate their movements, which is fuse out of the body, and water is constantly like muskellunge, striped bass, and brown an example of the lateral line at work. Fish trying to diffuse in. This is particularly true trout have large, well-developed eyes. They are also very sensitive to slight changes in at the gills because those tissues must be are able to see 360º, with the exception of water temperature. The fact that many very thin in order to promote diffusion of straight down and straight back. Because game fish carefully “mouth” soft plastic oxygen. Freshwater fish maintain an osmotic their eyes are placed forward on their bod- baits, suggest that their sense of touch is balance under these circumstances in two ies, they are in a perfect position for hunt- more sophisticated than we know. ways. First, they produce high quantities ing. Fish can discern brightness and color of very dilute urine, so they have very large, with rods and cones found in their retinas. Smell: Anglers are familiar with home- efficient kidneys. Second, they use special- Shallow water fish usually have excellent made and commercial “stinkbaits” that are ized chloride cells in the gills that are able color vision, but do not have the full range supposed to improve their chance of catch- to pump salt into the body against the of colors available to them that humans ing a fish. Stinkbaits work well because concentration gradient. Saltwater fish have possess. Water filters out color, so reds are fish have a well-developed sense of smell. the opposite problem. They arehyposmotic lost first as one goes deeper, then yellow, Pacific salmon are hatched in streams high (less salty than the surrounding water), so followed by blue. Some fish, like bullhead in the mountain ranges of western North salt is constantly trying to diffuse into the catfish, have “beady” eyes and poor vision. America, leave for the ocean after a year body and water out of the body. Saltwater Bullheads spend much of their time in of growth, swim for years in the Pacific fish use essentially the same machinery as deeper, murkier areas of ponds, lakes, and Ocean, then return as adults to spawn in freshwater fish to maintain osmotic balance, rivers. They rely on other senses to help the same stream reach where they hatched but they run it in the opposite direction. them get their next meal. from eggs. Pacific salmon find their natal Their kidneys produce small amounts of stream using their remarkable sense of very concentrated urine, and their chloride Hearing: Remember your physics? Sound smell. Displaced sunfish can find their way cells pump salt out of the body. travels four times faster in water than in air, back to their home area through smell. so most fish have developed a keen sense Minnows give off warning odors that signal As if all of this osmoregulatory activity of hearing. Fish don’t have ears, so how do other members of their school to disperse. was not challenging enough, consider they accomplish this feat? They usually Female fish emit odors that are picked up the obstacles that certain species, such pick up sound directly through the bones by males when it is time to mate. as striped bass, face when they migrate of the head. Fish equilibrium is maintained between fresh- and saltwater as part of through this inner ear, which is a chamber Taste: If you have ever observed fish in their life cycle. They must exactly reverse containing otoliths and other sensitive an aquarium, you may have seen that they all of their osmoregulatory apparatus as receptors. In some fish, such as minnows, are quick to “spit out” unsavory food items.

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Brook trout are known to strike anything guarders. Nonguarders include fish that lay spawn there, why leave in between? The from floating hemlock needles to hand-tied pelagic, or drifting, eggs. Shad eggs drift answer seems to be tied to solving the flies. They are quick to reject the hemlock downstream until they sink and become “grow or spawn” problem. In order to be debris, indicating that they, too, have a lodged in the substrate. Other nonguard- a successful spawner, the fish needs to be sophisticated sense of taste. Common carp ers may deposit their eggs in natural or as large as possible. And, it turns out that can actually sense the difference between constructed hiding places or nests. The there is a lot more food in the ocean than sweet, salty, bitter, and acid taste. Taste male central stoneroller (Campostoma in freshwater. If you want to get big, you buds are located on the head of a fish, anomalum) carries stones away from the need to go to the ocean to eat. So, the fish concentrated on barbels (like catfish), on breeding area, forming a pit in which has adopted a very complicated strategy: be their lips (common in suckers), or inside the eggs are laid. In many chub species, born in freshwater, make dangerous migra- their mouths. the males carry stones in their mouths tions to saltwater in order to grow, and to create a large rock pile nest. In several then return to freshwater to reproduce. Growth, Reproduction, species of darters, the female shuffles into and Life History the gravel and buries eggs. The advantage And, just when all that seems to make of gravel spawning is that the loose gravel sense, consider the American eel. It under- Most animals grow to their adult size and allows water to pass through, bringing goes a catadromous migration. American then stop getting bigger. Fish, on the other oxygen to the buried eggs. There is also eel are born in saltwater (in the Sargasso hand, continue to grow larger and larger variation among nest-guarding fishes. After Sea off the coast of Bermuda), migrate to throughout their lives, assuming enough an elaborate courtship, female sculpins freshwater, where they grow to adulthood, food and space is available. “Indeterminate attach sticky eggs on the underside of a flat and then return to the Sargasso to spawn growth” has profound effects on every part rock, which is then guarded by the male. and die. If fish migrate to where the food of a fish’s life cycle, especially reproduction. Sunfishes and bass create nests in gravel or is, why do striped bass and eels migrate To understand why, you need to under- vegetation, which are guarded by the male. in different directions to find food? After stand how fish use the energy they obtain Some catfishes seek out cavities in which all, in Virginia, both species can be found from their food. The energy a fish gets in to lay their eggs and protect them from in the very same rivers and migrate to the its food must be divided up and used for predators. An advantage of guarding a nest very same ocean, but in opposite direc- growth, reproduction, and metabolism. is it reduces the chance of eggs being eaten tions. The answer is a bit complicated and This is true for all animals, but because fish before they hatch, thus increasing the odds has to do with the evolutionary history of have indeterminate growth, they have an of the offspring’s survival. extra choice. Should they devote energy to the two species. The ancestors of striped getting bigger or to reproduction? (Assume bass evolved in freshwater, so that is where for the moment that they have little choice today’s striped bass must spawn (changing about putting a given amount of energy to- something as basic as where you spawn wards metabolism). Other animals do not is not easy). The ancestors of eels evolved have to make this choice, once they reach in saltwater, so that is where they must adulthood, because they stop growing, and spawn. The reason they each decided to migrate to food in another habitat also all their energy can go to metabolism and Figure 12-8. Male chubs from the genus Nocomis reproduction. carry stones in their mouths to create spawning seems tied to where the ancestors originally mounds. (Drawing by Mike Pinder.) evolved. Striped bass evolved in temperate The choice about whether to grow or zones, where the ocean is more productive reproduce is made even more complicated The tough choice between growth and than freshwater, and eels in tropical zones, because the two are related. It is almost reproduction has produced some very where the reverse is true. Striped bass had universally true in fish that bigger females interesting life history strategies in fish. to go to the ocean to find the most food, can produce more eggs, and bigger males A life history strategy is a set of behaviors and eels had to go to the rivers. Then, as attract (and can defend) more mates. used to complete important parts of the eels expanded their range northward out- So, it makes sense that the fish wants to life cycle, such as finding a mate, rearing side the topics, they retained their migra- get bigger in order to have more success young, and obtaining food. For example, tory habits, even though they do not seem when reproducing. But, as we’ve just seen, striped bass, shad, and herring, have all to make much evolutionary sense anymore. getting bigger actually takes energy away evolved a life history strategy that includes As you might predict, there is some recent from reproduction itself. Fish face a tough anadromous migrations, where they are evidence that eels in the north (where the choice, grow big now and reproduce later, born in freshwater, migrate to saltwater as ocean is more productive than freshwater) or reproduce now, but stay small. juveniles, grow to adulthood in saltwater, are not all migrating to freshwater any- and then return to freshwater to spawn more. There seems to be a population of Fish adaptations to different environments (and in many cases die). Why would a northern “ocean eels” that stay in the ocean include different reproductive strategies or fish go through such a complicated life where food is abundant. breeding habits. Most freshwater fish in cycle? Wouldn’t it be better to just stay in Virginia can be grouped into two differ- freshwater the entire time? After all, if you Eels and striped bass are just two of ent categories, the nonguarders and the are born in a place, and you will eventually Virginia’s more than 200 freshwater fish

2019 • Publication 465-312(CNRE-73P) Virginia Master Naturalist Basic Training Course Ichthyology 15 species, but there is an important lesson and the downstream area too. In a recent Poor agricultural practices that result in to be learned from them: fish life histo- assessment of threats to freshwater fauna, vegetation removal in riparian and flood- ries are extremely flexible. Fish display a team of researchers reported that altered plain areas, increased chemical application an incredible array of life history strate- sediment loads and nutrient inputs from (fertilizers, pesticides) near waterways, gies, so it is not possible to make broad agricultural and urban nonpoint source and allow direct access of animals to generalizations. Even within a species, big pollution are the top threats in the eastern waterbodies. differences occur. The rainbow trout that United States (Richter et al. 1997). Sedi- live in Virginia’s rivers for their entire lives ment is the leading cause of water quality Road and bridge construction that alter are the exact same species as the steelhead impairment in America’s waters, including stream banks and channel characteristics, trout that grow to over 20 pounds in the the Chesapeake Bay. Early studies on the increase sediment loading, and degrade Pacific Northwest and make anadromous impact of sediment on fish were related to water quality. migrations to the ocean and back. The the mortality of the egg and juvenile stages point is that if you boldly say, “This is how of salmonids. Salmon and many other fish Residential, industrial, and commercial this species completes its life cycle,” you are species spawn in nests built with coarse development that increase impervious sur- likely to be right for some rivers and lakes substrate such as gravel. The eggs and fry faces within watersheds, increasing surface but wrong for others. As a naturalist, your are dependent on clean interstitial spaces runoff, sediment loads and temperatures in job is to figure out howyour fish inyour between the gravel for water flow to help streams, and pollutant loading to streams river behave. This is both the frustration with oxygenation and waste removal. Mor- and shallow groundwaters. and the fascination involved with studying tality occurs when these spaces become fish: they are wonderfully, maddeningly, clogged with fine sediment and silt. High Sand and gravel mining in streams and riv- complicated. levels of deposited sediment can cause the ers that alter the bottom composition and loss of habitat quality and quantity and stability, resulting in changes to channel morphology. Threats and Issues Relating result in large reaches of streams that lack fish. Suspended sediment and turbidity Channel modifications, including en- to Fish in Virginia can impair the feeding ability of fish that largement, realignment, and straighten- are sight feeders, resulting in decreased “Freshwater species in the United States ing; removal of instream or stream-bank growth rates and health. Fish gills can are disappearing at a rate two to five times vegetation and woody debris; and bank also be clogged with fine sediment causing faster than native land animals, a rate equal stabilization using riprap or concrete that impaired respiration. Overall, excessive to those of tropical rain forest fauna” (Hel- increase water velocity and soil erosion. frich et al. 2003). Anthropogenic distur- sediment may result in increased physi- ological stress and decreased tolerance to bances, or human activities, are the greatest Exotic Species source of threats and issues to Virginia disease and toxics. fishes and their habitats. Such activities The introduction and transfer ofexotic include land use and channel alterations, In Virginia, like most of the eastern United species or the transfer of nonnative spe- pollution, and introduction of invasive spe- States, forests have been cut for timber or cies to new areas are the greatest threats cies, resulting in habitat loss and degrada- cleared for farmland for the past 300 years. to Virginia’s ecosystems after habitat tion, the leading cause of fish and aquatic Currently across much of the common- fragmentation and destruction. Exotic resource imperilment. wealth, forested and agricultural lands are species typically have no natural preda- being converted into residential areas and tors. They can impact native fishes through Fish kills and other impacts, some not industrial and commercial areas. Land use increased predation, transfer of diseases so visible to the casual observer, occur to and channel alterations affect the aquatic and/or parasites, and competition for food fish and their habitats as the activities of ecosystem in many ways. Individual fish, and space. Exotic species may breed with humans disturb aquatic ecosystems and fish populations, and fish communities can native fish, resulting in hybridization and their ecological integrity. Understanding be threatened as well as their habitat. loss of native genetic purity (Jenkins and cumulative impacts and future threats to Burkhead 1993). Recent introductions of Virginia fishes due to human population exotic aquatic species to Virginia include growth, climate change, and emergent con- Sources of excessive the northern snakehead (Chana argus) and taminants present challenges to fisheries sedimentation from land and the zebra mussel (Dreissena polymorpha). and water resource managers. In this chap- channel conversion include: Zebra mussels, found in a quarry in Prince ter, we focus on sediment and its impact to William County in 2002, were success- fisheries. Pollution impacts to aquatic eco- (See Figure 12-9. Stream embeddedness) fully eradicated in 2006. Even though this systems are covered in depth in the chapter introduction was successfully eradicated, on Aquatic Ecology and Management. Logging and forest road construction that zebra mussel could be introduced to Vir- reduce canopy cover, alter flow regimes ginia again. Two exotic species of crayfish, Sediment and pollution impacts to water- (including groundwater), and increase the virile crayfish Orconectes( virilis) and the ways usually result from upstream land-use supply of organics and sediment to nearby red swamp crayfish Procambarus( clarkii), activities that impact the immediate area waters. are widespread in Virginia. Two other

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Figure 12-9. Stream embeddedness

exotic species, the rusty crayfish Orco( - States Fish and Wildlife Service Region their new homes quite readily. An example nectes rusticus) and the Southern White 5 (stretching from Virginia to Maine), is the smallmouth bass, which is native River crayfish Procambarus( zonangulus), Virginia has the most introduced fish to the Tennessee River but is now found have been introduced to river drainages species, with nearly 100. Within Region 5, throughout most of Virginia’s rivers. in adjacent states, so they may soon be stocking is the dominant pathway of fish more widespread in Virginia. All of these introductions, accounting for nearly 50 Uncertain Threats: Population introductions can impact native species percent of the species. Bait release is the Growth, Climate Change, and through direct competition and food-chain second most commonly used pathway and Emerging Contaminants disruption. aquarium releases (or escapes from tropical In 2005, Virginia supported an estimated fish farms) are third. Many fish species population of 7.6 million people. By 2030, According to the United States Geological were introduced by individuals and govern- the commonwealth is expected to reach 9.3 Survey’s 2004 Summary Report of Non- ment agencies into drainages outside their million people, a 22 percent increase over indigenous Aquatic Species in the United native range, and many have adjusted to 25 years. Virginia’s population growth will

2019 • Publication 465-312(CNRE-73P) Virginia Master Naturalist Basic Training Course Ichthyology 17 increase demand on water resources. Land- The striped bass is an anadromous fish, use alterations will increase with increasing spending part of its life in freshwater and population growth. The use of low-impact part in saltwater. Every spring, striped bass and smart growth development techniques return to the Chesapeake Bay and its tribu- may mitigate impacts to Virginia’s fishes. taries to spawn. Many rivers used by this Regardless of the magnitude of change in species for spawning are blocked by dams. meteorological events in Virginia, we can Dams cause two problems for striped bass, Figure 12-10. The brook trout is Virginia’s only na- they block upstream access for spawning expect drought impacts with increasing tive species from the Salmonidae family. (Drawing water demand. In other words, the next by Mike Pinder.) fish and they alter streamflow. The first protracted drought is not an “if,” but rather, problem is relatively straightforward, but a “when” scenario. Fishery and water- The brook trout is one nativeSalmonid the second problem may not be as obvious. resource managers must evaluate how requiring special management strategies Striped bass eggs are semi-buoyant and demographic and socioeconomic changes since they are an intolerant species with must remain suspended in the water col- affect Virginia’s vulnerability to critical specific habitat requirements. Brook trout, umn to develop properly. The eggs may fall climatic events, including impacts to water once found throughout the mountainous out of the water column and suffocate if resources and aquatic fauna. Emergent areas of the state, have had their range the right flows are not available. Changing contaminants such as pharmaceuticals, reduced over the past 100 years due to water levels, either from natural events or plastics, personal care and household nonnative trout introductions and habitat dams, greatly affects the likelihood the eggs products, and pathogenic microorganisms alterations. Brook trout require clean, will hatch successfully. The specific habitat are discharged with municipal effluent and cold water to thrive. These fish are greatly requirements of the striped bass often lead other human and animal waste streams impacted by increasing water temperatures to erratic differences in spawning success into our waterways. Although discharged and sedimentation, which often results from year to year. at low levels, many of these compounds from development, agriculture, or logging. are persistent in the environment and may Many populations of brook trout have It is important to understand the role spe- cific habitats play in the lives of fish. Differ- bioaccumulate in long-lived organisms. been pushed to the headwater sections ent fish require different habitats. If we Impacts to fish from these emergent com- of streams due to these disturbances. lose habitat diversity and integrity, we will pounds may include altered reproduction, Increased awareness of these habitat lose much of Virginia’s fish diversity. Many fetal and nervous system development, and requirements has helped to protect many threatened and endangered species require increased susceptibility to disease. of Virginia’s headwater streams from im- proper logging and development practices. very specific habitat. Long-term stability of stream ecosystems is strengthened by Rare or Special Species that habitat and fish diversity. Population vul- nerability to environmental changes often Indicate Habitat Quality increases as species richness declines. As you’ve already read in earlier sections of Recognizing unique fish species and the the chapter, Virginia has a rich diversity of habitats they live in will help protect the fish. Many of these species require specific integrity of all of our stream ecosystems. habitats, such as riffles, certain substrate, Figure 12-11. The Roanoke logperch (Percina rex) is a state and federal endangered species affected or cold water temperatures. These habitat Methods for Studying Fish by sedimentation due to poor erosion and sediment qualities are often altered as land use or control practices. (Drawing by Mike Pinder.) The fisheries resources of the United climate changes take place. The effects States are a public resource managed for of these changes depend on whether the The Roanoke logperch Percina( rex) is the benefit of the American people. The animal is a generalist or a specialist. a state and federal endangered species responsibility for management is shared Generalists can often tolerate significant endemic to the Roanoke and Chowan river among federal and state governments and disturbances while specialists may not be drainages. This rare fish feeds by flipping Indian tribes. With some fish being har- able to cope with habitat degradation or rocks with its long snout to eat the macro- vested for food and others suffering from alteration. Several of Virginia’s fish species invertebrates underneath them. Due to this over-harvest or degraded habitat, fisheries are listed as threatened or endangered. feeding behavior, the Roanoke logperch biologists work to maintain viable popula- A current list of these species is available is very susceptible to sedimentation that tions of many species. Managing fish on the Virginia Department of Game and fills in its feeding habitat. Strict erosion populations requires collecting a host of Inland Fisheries website. Listing by state and sediment controls must be used by information. Important information needs and federal agencies provides the animals developers and construction firms in are population size, rate of growth, size at with extra protection from development watersheds containing the species. Because first spawning, harvest, habitat health, and and changing land use. Rare and unique young logperch use backwaters and adults societal desires. The job of fisheries manag- species often have very specific habitat use fast flowing riffles and runs, a variety of ers is to gather and analyze the data and to requirements that complicate management habitats must be made available to them to balance societal desires and the resource efforts. ensure their long-term survival. needs.

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Population size is generally estimated using gear can be divided into active and passive Basic Principles of two methods, mark/recapture and deple- types. Active gear is moved to intercept and tion sampling. Mark/recapture methods capture fish. Common active gear includes Fisheries Management collect fish, give them a recognizable mark seine nets, trawl nets, and electrofishing. Depending on who you are talking with, (using a fin clip or tag), then release them, Seines are generally used in still or slow fisheries management can mean many allowing them to mix with the popula- flowing shallow water to capture smaller things. To private landowners, it may tion. Later fish collection in the same area fish. One end of the seine is held on shore, mean fish stocking in their small ponds. To captures both marked and unmarked fish. the other end is pulled into deeper water, members of Trout Unlimited, it may mean Estimates of the population size are cal- then parallel to shore, and then pulled back removal of introduced trout species from culated based on the ratio of marked and to shore. Trawl nets are funnel shaped and their favorite native brook-trout stream. unmarked fish. Depletion sampling cap- generally used in large bodies of water. To bass anglers on a Virginia reservoir, it tures and temporarily removes fish from an They can be sized to capture various sizes may mean highly restrictive size limits on area until few, if any, fish remain in the area of fish. A trawl is attached to a boat and harvest to help develop a trophy fishery. sampled. Population size is approximately pulled through the water at a speed that To concerned consumers, it may mean the total number of fish captured. exceeds the fish’s ability to escape. The net government or international regulation can be run at various depths, depending on of commercial fishermen to help improve Fish growth is an indicator of the habitat the habitat occupied by the species being the over-harvested state of most global quality and the number of fish compet- collected. Electrofishing is conducted by fish stocks. All of these stakeholders have ing within the habitat. Fish scales, spines, introducing electricity into the water. Fish something in common: they want to see or bones are examined to determine age. that are intercepted by the electric field are an improvement in a particular fishery, and Aging trees via counting rings is a good either immobilized or drawn toward one they look to fisheries managers to bring visual comparison, although fish age and of the electrodes, where they are netted. about that improvement. A fishery, then, growth determination is more complex. By Electrofishing gear is manufactured for is really just a system wherein users harvest knowing a fish’s length and weight at its mounting on a boat, or carried on the back. some type of benefits from aquatic organisms. current age, a biologist can calculate its size Boat mounted gear is used in lakes or large And that brings us to a working definition at earlier ages. Growth rate is a measure rivers. Backpack electrofishing gear is used for fisheries management: the intentional of the population health in relation to the to sample small rivers and streams or other manipulation of fish stocks and related fac- habitat and other populations. shallow water. It is carried by a biologist, tors to produce benefits important to human who, with assistance from other waders, users. Fisheries management occurs at the It is important to protect enough spawn- nets the fish captured in the electric field. intersection of three important dimensions ers to maintain or, in some cases, increase of a fishery: population size. By capturing fish during Passive gear works by taking advantage spawning season, biologists determine age of fish movements and includes trap nets and size of sexually mature fish. Public de- and gill nets. Trap nets function by leading Resource mands sometimes require supplementing the fish along a blocking net (usually set Fish Users populations that, for various reasons, can- perpendicular to shore) through a series not sustain themselves. Fish are captured, of funnels into a holding area. The fish are Populations Fishery spawned artificially, raised in a hatchery netted out of the holding area. Gill nets, Management and then stocked. which are suspended in open water areas, entangle fish that attempt to swim through Harvest is generally divided between com- them. Gill nets and trap nets typically are mercial harvest and recreational harvest. used in lakes, reservoirs, or slow-moving Critical Fish mortality is divided into natural and rivers. The size or the openings in both gill Habitat harvest mortality. Harvest mortality is de- and trap nets can be pre-selected to capture termined by directly observing the fishery the size and species of fish sought. Other or by indirect calculations of change in passive gear includes radio-telemetry, population size that is greater than what photography, sound, and other high tech Fish populations themselves are the most would occur from natural mortality. devices that count or otherwise detect fish obvious emphasis in fisheries management without capture. programs, but in reality we don’t really Biologists cannot sample entire populations, have a fishery unless we have people using so it is necessary to capture a representative Most of these sampling techniques require the resource in some way. It may be the sample to provide the information necessary special training and permits so they are not typical consumptive use, where the benefits to make scientifically sound decisions. To recommended as ways for Master Natural- to people are primarily the fish harvested. determine the proper type of capture gear ists to study fish. Master Naturalists can But there are many examples of benefits to be used, fish biology, characteristics of observe fish in streams and rivers using that people gain from fisheries without the waterbody, and, most importantly, study techniques like snorkeling and other visual harvesting the fish (e.g., catch-and-release objectives must be considered. Fish capture observation devices. fisheries, or members of conservation

2019 • Publication 465-312(CNRE-73P) Virginia Master Naturalist Basic Training Course Ichthyology 19 organizations who derive a psychological management programs have been in place fish). Table 3 lists some examples of typical benefit from just knowing that our aquatic to control harvest and other uses for many fisheries management actions involving ecosystems are healthy). Directing the use decades. The management of fishery habitat. of fish populations by people constitutes a users typically takes the form of restric- powerful and important tool for fisheries tive regulations. Regulations generally are managers. Finally, sustainable fish popu- designed to reduce the impacts of harvest Interacting Management lations cannot exist without the proper on fish populations, spread the sustainable Factors: Fisheries in Small habitat (for spawning, feeding, hiding from harvest between more anglers, or to protect Ponds in Virginia predators, etc.), so habitat management can particularly sensitive species or popula- be a critical component of management tions. Table 2 lists some typical approaches The management challenges of small programs. Let’s look more closely at each to the use of regulations in Virginia and ponds offer the perfect example to of these management areas in the context other states. Fisheries managers also survey demonstrate the interaction of the three of typical fisheries management programs anglers frequently to assess their desires for components of fisheries management. Let’s in Virginia. and satisfaction with fishing opportunities. look at typical scenarios for small ponds in This gives managers valuable information Virginia. Fish populations by which to adjust their management plans for various bodies of water. The direct manipulation of fish popula- Fish populations Landowners with new ponds typically tions to improve fisheries can take many Critical Habitat forms. Since the dawn of fish culture in the consult one of the many available pond U.S. in the 1800s (and, actually, in Asia Different types of habitat are critical for management guides. Initial stocking of a over 2000 years ago!), fish stocking has various life stages of fish. Natural stream new pond typically is 500 bluegill or redear been thought of as perhaps the primary channels provide lots of habitat variety for sunfish per acre in the first summer or fall, tool for fisheries managers to improve fish fish (pools, riffles, runs, boulders, woody followed by 50 fingerling largemouth bass populations. Stocking can take three differ- debris, etc.), but human activities often per acre the following year (introductory ent approaches (as illustrated in Table 1), modify stream characteristics by remov- stocking). To increase variety in sportfish- and each approach has associated objec- ing flow impediments and increasing flow, ing opportunities, channel catfish are often tives and costs. Fish stocking is only a small usually to reduce flooding problems in added as a maintenance stocking (50 per part of effective management, and fisheries human habitats. Fisheries managers may acre, every other year). managers also perform many other actions try to return sections of streams to a more to influence and improve fish populations. natural state, which will generally increase Resource users habitat diversity and improve fish popula- Managers may take steps to reduce un- Fishing on small ponds is popular, particu- wanted fish species (such as common carp tions and fishing. Fisheries managers in Virginia also face issues of habitat quality larly for children. A well-balanced pond or overabundant sunfish in ponds, lam- can easily withstand light to moderate preys in the Great Lakes, snakeheads in the in standing waters. Given that there are only two natural lakes in Virginia (Moun- fishing pressure, particularly if catch-and- Potomac River, or nonnative rainbow and release is practiced for largemouth bass. brown trout in native brook trout streams). tain Lake, and Lake Drummond), most of what we think of as “lakes” in Virginia are But, it is very easy to overharvest bass from The feeding of fish can be a popular ap- a small system, which results in an unbal- proach to trying to improve fisheries in actually artificial reservoirs. These reser- voirs were often cleared of standing forests anced fish population, stunted sunfish, and small ponds, but it is rarely effective. Poor before impoundment, so many reservoirs unhappy anglers. Small ponds typically condition of fish is more typically a symp- have very limited fish habitat. The same support a standing crop of approximately tom of improper harvest, which brings us is true for many small ponds, which often 40 pounds per acre of sunfish and 10 to the second area of emphasis for fisheries are formed in pasture areas. In both these pounds per acre of largemouth bass. management actions. cases, fish populations can benefit from Considering that less than 50 percent of the placement of habitat enhancements, the bass population may be of catchable or Resource users such as simple brush shelters, old Christ- harvestable size, you only need to harvest Users obviously have a direct impact on mas trees, etc. In some cases, ponds and a few nice fish to throw a small pond (e.g., any resource that they use, and fisheries reservoirs may suffer from an overabun- one to two acres) out of balance. Typically, are no exception. Most global fisheries dance of structure, in the form of dense bass harvest should be matched to sunfish are in poor condition because too many aquatic weed beds. While these plants may harvest. If a pound of bass is removed, people are harvesting too many fish for the enhance survival of small fish, they often then at least four to five pounds of sun- populations to sustain themselves. Fish are lead to stunted prey fish populations and fish should be removed to maintain the being harvested before they have a chance unhappy anglers and other lake users. A predator/prey balance. If this is not done, to reach optimum sizes or, in many cases, variety of measures are used to control sunfish will quickly overpopulate and stunt even reach reproductive size. Freshwater overabundant aquatic weeds, including me- in size, interfere with bass reproduction, fisheries in the U.S. are in much bet- chanical removal, chemical treatment, and and the quality of the fishing will decline ter shape than most global fisheries, as the stocking of grass carp (an herbivorous even further. At that point, the only option

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is to correctively stock adult largemouth an agricultural watershed, or when lawn problem (overabundant rooted vegetation), bass (which is very expensive), or to poison fertilizers or sewage find their way into but can create another (poor survival of the entire population and start over with the pond. The only permanent solution newly hatched fish, who need some type of new stocking. In the long run, it is easiest is to cut off the flow of nutrients, but this cover to hide from predators). In this case, to maintain pond balance by practicing often is not feasible. So, pond owners are effective cover for young fish can be pro- catch-and-release for largemouth bass on faced with using other methods to control vided with brush or Christmas trees placed small ponds. Maintaining a healthy bass nuisance aquatic vegetation. Typically they along the shoreline in shallow water. population will also produce sunfish of may treat with chemicals (a very expensive exceptional size, which can produce lots of proposition for rooted aquatic plants, but fishing enjoyment and be harvested with- more reasonable for algae problems such Summary out harming the balance of the pond. The as filamentous species), but this approach Fisheries management is a science that main point here is that improper use of the must be repeated every few years as the touches not just anglers, but all people resource can result in ecological problems problem vegetation returns. A more per- interested in aquatic habitats. Effective that can only be corrected by direct action manent solution for problems with many fishery managers must appreciate all three on the fish population by managers. rooted aquatic plants is to stock an her- dimensions of a fishery (the fish popula- bivorous fish species, the grass carp. Grass tion, the resource users, and the impor- Habitat management carp stocked at very low rates (as few as tance of critical habitat) if they are to be The most common habitat problem on 10 to 15 per vegetated acre) can effectively successful. Most people think first of fish small ponds is overabundant aquatic control problem plants. However, be aware when they think about fishery manage- plants. This problem typically results that in Virginia only “certified triploid” ment, but in truth it is the resource users from improper pond design (the pond grass carp (fish that have been genetically who have the most impact on the char- is too shallow, or the banks do not have modified to prevent reproduction) can be acter and success of a fishery. We need to sufficient slope), or from outside input of stocked, and a permit is required from the remember that without the resource users, nutrients into the pond. Excess nutrients Virginia Department of Game and Inland there really would be no fishery, or a need are often a problem when the pond is in Fisheries. Stocking grass carp can solve one for fishery management.

Table 1: Examples of stocking types used in Virginia fisheries. Type of Stocking Objective and Costs Examples Introductory stocking A single or few introductions to establish Brown trout in the Smith River: An introduced species repro- a self-sustaining population; limited cost ducing naturally. (one-time management expense). Smallmouth bass in the New and James rivers: Introduced populations spawning naturally and supporting popular fisheries.

Gizzard shad in numerous reservoirs statewide: Provide for- age for sport fishes. Supplemental stocking Intermittent stocking to supplement Muskellunge in the James and New rivers: Stocked regularly limited natural reproduction (ongoing in relatively small numbers; populations also are likely sup- moderate expense). ported by limited natural reproduction. Maintenance stocking Continual stocking to maintain a popula- Striped bass in Smith Mountain Lake: Thousands are stocked tion that cannot reproduce naturally; annually to maintain a popular fishery. cost is very high, and can only be justified when abundant benefits are produced. Rainbow trout in put-and-take streams: Habitat does not allow reproduction and year-round survival.

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Table 2: Examples of fishery regulations used in Virginia and other fisheries. Type of Regulation Objective Examples Fishing license Provide information on angler numbers Statewide freshwater license and funding for management programs. Saltwater recreational license

Various saltwater commercial licenses Restrictive size limits Protect fish until they can reach spawning 14”-24” slot limit for largemouth bass in Briery Creek Lake: age or size or some target length or length Bass in this size range must be returned alive, in order to build range to produce a desirable size structure a trophy bass population. in the population. 42” minimum size for muskellunge on the New River: In- tended to build a trophy population.

No size limits on crappie and bluegill statewide, because most sunfish are breeding by the time they are 2 years old. Creel (bag) limits on Spread the total allowable harvest be- Daily limits of 50 bluegill and 25 crappie on most public harvest tween a large number of anglers. waters in Virginia.

Daily limit of 2 striped bass on Smith Mountain Lake. Catch-and-Release Protect sensitive populations, allow lim- American shad in sections of the James and Pamunkey rivers. ited escapement for spawning, or preserve limited benefits for more anglers. Trout on special sections of the Dan, Rapidan, and Holston rivers. Closed seasons Reduce disturbance of spawning fishes. No closed seasons are used in Virginia and most other south- ern states.

Closed seasons to reduce disturbance of spawning fishes are common in some northern states.

Table 3: Examples of fisheries habitat improvement techniques. Habitat Improvement Action Objective Examples Control of nuisance aquatic weeds Improve access for boaters and anglers. Limited chemical spraying at Claytor Lake

Stocking of grass carp at Lake Gaston Leaving standing timber in reservoirs at the Provide cover for fish and improve fishing by concentrating Briery Creek Lake time of construction fish. Lake Moomaw

Nottoway Lake Installing brush shelters (Christmas trees, Provide cover for small fish to improve survival and im- Christmas trees sunk in alder bundles, stump placement) prove fishing by concentrating fish. Claytor Lake and Hungry Mother Lake Large woody debris and boulders placed in Improve habitat for trout and other stream species; create North River streams cover from current, pools, etc. Fertilization of small ponds Increases phytoplankton and zooplankton densities and Lake Orange fish carrying capacity; can decrease weed problems by blocking sunlight, but can increase weed problems if done Lake Brittle improperly. Liming Reduce the effects of acid precipitation. Laurel Bed Lake

St. Mary’s River

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• Compressiform – Flattened laterally, or • Fin Rays – Bony spines supporting the from the sides. lossary soft membrane of a fish’s fin. • Ctenoid Scales – Fish scales with an • Fishery – A system wherein users har- • Adipose Fin – A fleshy fin located be- exposed margin resembling the teeth of a vest some type of benefits from aquatic tween the dorsal (back) and caudal (tail) comb. organisms. fins of catfish, trout and salmon ( Sal- • Cycloid Scales – Fish scales that are • Fisheries Management – The intention- ), and trout perch ( ). monidae Percopsidae rounded with a smooth edge. al manipulation of fish stocks and related factors to produce benefits important to • Anthropogenic – Pertains to the envi- • Depressiform – Flattened dorsoven- human users. ronmental influence of human activities. trally or from the top and bottom. • Anadromous – Lives adult life in salt- • Detritus – Organic material typically • Floodplain – The flat or nearly flat land water, spawns in freshwater. deposited on the bottom of a waterbody. along a river or stream or in a tidal area that is covered by water during a flood. • Anadromous Migrations – Migrations • Dorsal – Referring to the back or upper where adult fish move from the ocean body of a fish. • Frenum – Skin-covered tissue that links to freshwater to spawn, and juvenile fish the snout to the center area of a fish’s move from freshwater to saltwater to • Dorsal Fin – A median fin that runs upper lip. feed and grow to adulthood. down the center of the dorsal (back) region of a fish. • Fusiform – Fast-swimming, open-water • Anal Fin – A fin that runs along the fishes that are streamlined and elliptical • Ecological Integrity – A living system midline of the bottom of a fish near the in cross-section. that sustains and organizes self-correct- anus. ing ability to recover from disturbance • Ganoid Scales – Scales found on stur- • Barbel – One of the slender, whiskerlike toward an end-state that is normal for geon and gar that are armorlike, since tactile organs extending from the head of that system. End-states other than the they consist of bony plates covered with certain fishes, such as catfishes. pristine or natural whole may be ac- layers of dentine and enamel. cepted as normal and good. • Benthic – Of the bottom, refers to • Generalist – Animal that can live in a organisms that inhabit the bottom sub- • Ecosystem – The interacting system of variety of habitats and utilize several dif- strate, infrequently swimming above it. a biological community and its nonliving ferent food sources, usually referred to as environmental surroundings. tolerant species. • Bioaccumulate – The process by which chemical contaminants increase in • Effluent – Municipal sewage or indus- • Gill Arches – The bony structures that concentration as they move through the trial liquid waste (untreated, partially hold the gill filaments. food chain (by concentrating in preda- treated, or completely treated) that flows out of a treatment plant, septic system, • Gill Filaments – The red gill tissue tors that eat contaminated prey items). pipe, etc. Emarginate – A fin margin that where oxygen and carbon dioxide ex- change happens. • Catadromous – Fish that live in fresh is slightly concave in at the outer edge. water but migrate to saltwater to breed. • Emergent Contaminants – Any syn- • Gradient – The ratio of drop per unit distance, indicating flow conditions in a • Catadromous Migrations – Migrations thetic or naturally occurring chemical or stream or river. where adult fish move from freshwater any microorganism that is not com- to the ocean to spawn, and juvenile fish monly monitored in the environment • Gular – A large bony plate positioned move from the ocean to freshwater to but has been recently detected in the under the bottom jaw of such primitive feed and grow to adulthood. environment. fish as the bowfin. • Caudal Fin – A fin at the posterior end • Endangered Species – A species in danger • Heterocercal – A type of caudal fin that of the body of a fish (also known as the of extinction throughout most of its range. has the vertebral column extending into tail fin). • Endemic – Restricted in occurrence to the upper lobe of the caudal fin. A primi- tive type of tail found on sturgeon. • Caudal Peduncle – The tapering a particular and usually relatively small area. portion of a fish’s body between the • Hyperosmotic – The condition of posterior edge of the anal fin base and • Exotic Species – A species accidentally or having body tissues more salty than the the base of the caudal fin. intentionally introduced into areas beyond surrounding water. Freshwater fish are their native, natural geographic range. hyperosmotic. • Chloride Cells – Specialized cells in the gills that can pump salt into or out of • Extirpated – A species that has been • Hyposmotic – The condition of having a fish’s body against the concentration eliminated from a particular area, but body tissues less salty than the surround- gradient. still exists somewhere else. ing water. Saltwater fish are hyposmotic.

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• Imbricated Scutes – A large, thick scale • Otoliths – A structure of the inner ear • Scute – A large, thick scale or plate that or plate that has been adapted for body of some animals, such as fish, that is has been adapted for body protection. protection. The term imbricated refers made of calcium carbonate. It allows the • Sediment – Soil, sand, and minerals to the fact that these scales overlap in a animal to detect changes in orientation. washed from land into water, usually regular pattern. • Pectoral Fin – Either of the anterior after rain. • Indeterminate Growth – The situation pair of fins attached to the pectoral • Specialist – Animal that requires a whereby an organism continues to grow girdle of fishes, corresponding to the specific habitat or prey to survive, also its entire life, as long as food is avail- forelimbs of higher vertebrates. generally referred to as an intolerant able, without ever reaching a maximum species. adult body size. Fish show indeterminate • Pelagic – The open water area of a lake or reservoir. growth, but most other organisms do • Species Richness – The measure of an not. • Pelvic Fin – Either of a pair of lateral ecosystem’s biodiversity, determined by counting the number of species in a given • Inferior Mouth – One with an open- hind fins of fishes, attached to the pelvic ing under the head, with the upper jaw girdle and corresponding to the hind area, also known as species diversity. limbs of higher vertebrates. protruding well out in front of the lower • Spines – Hard, boney-like filaments jaw. • pH – A measure of the acidity or alka- used to stiffen fin tissue. • Intromittent – An external reproductive linity of a solution on a scale of 1 to 14, • Stream Capture – A phenomenon organ used in copulation. with a value of 7 being neutral. Values caused by geologic activity, whereby less than 7 are acidic, and values greater a stream leaves its own bed and flows • Karst – An area with limestone geol- than 7 are alkaline. ogy, expressed in sinkholes, caves, and down the bed of a neighboring stream. springs. • Pharyngeal – Throat area (between the • Subterminal Mouth – Fishes with an head and the body cavity). upper jaw reaching slightly beyond the • Lateral – The side (between the dorsal and ventral surfaces). • Piscivore – A fish eating animal. lower jaw. • – Fishes with a lower • Lateral Line System – A sense organ • Pollutant – Any substance introduced Superior Mouth running along the side of a fish’s body into the environment that adversely jaw projecting beyond the upper jaw. that is capable of detecting pressure affects the usefulness of a resource • Swim Bladder – A gas-filled hollow waves in the water. This system is used to or the health of humans, animals, or organ lining the body cavity, used to help detect moving objects in the water and to ecosystems. the fish maintain neutral buoyancy in the coordinate schooling behavior. • Pseudobranchae – A small patch of water. • Life History Strategies – A set of be- vascularized gill filaments attached to the • Terminal Mouth – Fishes with jaws that haviors used to complete important parts inner region of the gill cover. Pseudo- are relatively even in length and meet at a of the life cycle such as finding a mate, branchae are found in species of the point at the tip of the head. rearing young, and obtaining food. Moronidae family. • Thoracic – The ventral surface behind • Macroinvertebrate – Animals without • Pterygiophore – A bone used to raise the head of the fish, below the pectoral a backbone that can be seen without a and lower rays and spines in the fins. fin bases. The pelvic fins are sometimes microscope. located here. • Rays – Soft, branched filaments used to • Myomeres – Fish muscles. stiffen fin tissue. • Threatened Species – A species likely to become endangered in the immediate • Nocturnal – Active at night. • Riparian – Area of vegetation along a future. river or stream corridor that offers wild- • Nonindigenous – Not native to a given life habitat and helps absorb runoff from area. • Ventral – Bottom or underside of an the land during storm events, generally organism. • Nonpoint Source Pollution – Diffuse regarded as relatively narrow compared • – A chain of small pollution sources (i.e. without a single to a floodplain. Weberian Apparatus bones that connects the auditory system point of origin or not introduced into a • Roe – The eggs or the egg-laden ovary of to the gas bladder of fishes, allowing the receiving stream from a specific outlet). a fish. transmission of vibrations to the inner • Operculum – The gill cover of a fish. ear of some fish. • Runoff – That part of precipitation, • Osmogregulation – The process by snowmelt, or irrigation water that flows • Zoogeography – The study of dis- which an organism maintains the correct from the land into streams or other tribution patterns of animals and the balance of salt and water in its tissues. surface water, often carrying pollutants. processes that regulate their distribution.

2019 • Publication 465-312(CNRE-73P) 24 Ichthyology Virginia Master Naturalist Basic Training Course Additional Resources Study and American Sportfishing Association. 2018. Helfrich, L.A. and R.J. Neves. Freshwater Review Sportfishing in North America: An Eco- Fish Biodiversity and Conservation. nomic Engine and Conservation Power- Virginia Cooperative Extension Questions house. Available from https://asafishing.org/ publication 420-525. Available from 1. What ichthyologist wp-content/uploads/2019/02/Sportfishing-in- https:// . described the majority of America-Revised-November-2018.pdf www.pubs.ext.vt.edu/420/420-525/420-52 5.html. Virginia’s fishes? Bond, C.E. 1996. Biology of Fishes. Brooks/ Cole, London. Hynes, H.B.N. 1970. he Ecology of 2. How many fish families Run-ning Water. Liverpool University and how many fish species Bryan , C.F. and D.A. Rutherford, edi-tors. Press, Liverpool, England, U.K. are found in Virginia? 1993. Impacts on warmwater streams: guidelines for evaluation, Second Edition. Jenkins, R.E. and N.M. Burkhead. 1993. 3. What system in fish is Southern Division, American Fisheries Freshwater Fishes of Virginia. American their primary means of Society. Fisheries Society, Bethesda, Maryland. sensing touch? Bugas, Jr., P. E., C. D. Hilling, V. Kells, M. Moyle, P.B., and J.J. Chach, Jr. 2003. 4. What are two life history J. Pinder, D. A. Wheaton, and D. J. Orth. Fishes: An Introduction to Ichthyology. strategies used by Virginia 2019. Field Guide to Freshwater Fishes of Prentice Hall, Upper Saddle River, N.J. Virginia. Johns Hopkins University Press, fishes? Baltimore, MD. Ney, J.J. and L.A. Helfrich. 2003. Selected Freshwater Fish Families. Virginia Coop- 5. What is the greatest threat EFISH: The Virtual Aquarium. erative Extension publication 420-526. to Virginia fishes and their Department of Fish and Wildlife Available from https:// habitats? Conservation, Virginia Tech. https:// www.pubs.ext.vt.edu/420/420-526/420-52 www.efish.fishwild.vt.edu. 6.html. 6. Name a federal or state threatened fish mentioned Gilbert, C.R. and J.D. Williams. National Richter, B.D., D.P. Braun, M.A. Mendel-son, in this chapter. Audubon Society Field Guide to Fishes North and L.L. Master. 1997. Threats to America. 2002. Chanticleer Press, Inc. New imperiled freshwater fauna. Conservation 7. Name a method used by York, N.Y. Biology 11:1081-1093. biologists to study fish Hart, P.J.B. and J.D. Reynolds (eds). 2002. Rohde, F.C., R.G. Arndt, D.G. Lindquist, mentioned in this chapter. Handbook of Fish Biology and Fisheries, and J.F. Parnell. Freshwater Fishes of the 8. Fisheries management Volume 1: Fish Biology. Blackwell Publish- Carolinas, Virginia, Maryland, and Dela- ing, Malden, Mass. ware. 1994. University of North Carolina occurs at the intersection Press, Chapel Hill, N.C. of what three important Helfrich, L.A., R.J. Neves, and J. Parkhurst. dimensions of a fishery? October 2003. Sustaining America’s Aquatic Smith, C.L. 1994. Fish Watching: An Biodiversity: Why Is Aquatic Biodiversity Outdoor Guide to Freshwater Fishes. Cornell Declining? Virginia Cooperative Extension University Press, Ithaca, N.Y. publication 420-521. Available from https:// Waters, T.F. 1995. Sediment in Streams: www.pubs.ext.vt.edu/420/420-521/420-52 Sources, Biological Effects, and Control. 1.html. American Fisheries Society Monograph 7.

Acknowledgements

This chapter was a major project of the Outreach Committee of the Virginia Chapter of the American Fisheries Society, a subunit of the American Fisheries Society, the world’s oldest and largest organization promoting the scientific management of aquatic resources for the optimum use and enjoyment by the people of North America. A friendly review was provided by Don Orth. A major review was provided by Mike Pinder.

2019 • Publication 465-312(CNRE-73P)