Transcript Fish

A Fish Primer
WMAN 445
Intro Fish Management
August 31, 2006
Why Study Fish?
Academic
– Most diverse group of vertebrates
– Most ancestral vertebrate group
Understanding their evolutionary relationships
helps us understand the more derived groups
Applied
– Commercial and Recreational Fisheries
– Aquatic Health Indicators
Great Species Diversity
25,000 species (28,500)
More than any other vertebrate group
– 4,000 mammals
– 9,000 birds
– 7,000 reptiles
– 5-6,000 reptiles
Total of other vertebrates = 25-26,000
1 of every 2 vertebrates is a fish
Great Diversity in…
Size (blenny – whale shark)
Shape (sea horses, rays, eels)
Habitats occupied (streams, ponds, rivers,
bays, ocean, reefs, caves, thermal springs)
Feeding habits (benthic, engulfers,
shredders, cleaners, parasites, omnivores)
Reproduction (oviparity, viviparity, sex
reversal, semelparity, sneakers, mimics)
World Distribution of Fishes
Earth’s water
– 97% ocean
– 2.99% ice
– 0.01% freshwater
Fish Distribution
– 41% freshwater
– 58% marine
– 1% diadramous /
euryhaline
Why are so many fish species found
in freshwater?
– Isolation limits gene flow—speciation
events occur
– Diversity of habitats and evolutionary
niches
N.A. Distribution of Fishes
About 950 species
75% occur in the eastern U.S.
Mississippi River drainage most
diverse
– Tennessee drainage most diverse
– Atlantic slope least diverse
– New / Kanawha River basin
“relatively diverse”
Fishes in Peril
Fastest declining vertebrate group
– Dams
– Pollution
– Habitat Alteration
– Introduced species
– Over harvest
Fishes in Peril
What is a Fish?
Aquatic
Poikilotherm
Gill Breathing
Single-Loop Circulation
Vertebrate/Craniate
Fins (as opposed to
pentadactyl limbs)
Fish Classification
Binomial Name
– Genus specific epithet name of describer &
year
– E.g. Lepomis macrochirus Rafinesque 1819
– E.g. Lepomis megalotis (Rafinesque 1820)
Lepomis = scale shoulder
megalotis = large ear
Classification in General
Kingdom
Phylum
Class
Order
Family
Genus
Species
Higher taxonomic level the more inclusive
of groups
– Reflects natural evolution of groups
Fish Classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Superclass: Agnatha
– Order: Petromyzontiformes
Family: Petromyzontidae (Lampreys)
– Most primitive, no jaws, parasitic, non-parasitic, eel-like
Superclass: Gnathostomata
– Class: Chondrychthys (cartilaginous fishes)
– Class: Osteichthyes (bony fishes)
24,000 living forms
Largest class of vertebrates
General Characteristics
of Bony Fishes
Lungs
– Fish evolved in tropic freshwater environments
– Modified into buoyancy organs (swim bladders)
Bone
– Secondarily replaced by cartilage in paddlefish,
sturgeon
Bony scales
– Lost in many species (sculpins)
Lepidotrichia
– Segmented structural supports for fins; soft fin ray
Subclasses of Osteichthyes
Sarcopterygii (lobe finned fishes)
– Ancestor to tetrapods
Actinopterygii (ray finned fishes)
– Infraclass Chondrostei (sturgeons, paddlefishes)
Order Acipenseriformes
– Acipenseridae: sturgeons
Caviar, cartilaginous, bottom feeder, long-lived, slow
growth
– Polyodontidae: paddlefishes
Planktivores, carnivores, long sensory snout, little native
habitat
– Infraclass Neopterygii (modern ray finned fishes)
4 diverse lineages
Division Teleostei—main line of fish evolution
Order Lepisosteiformes
– Lepisosteidae: gars
Needle-like teeth
Voracious predators
– Amiiformes
– Amiidae: bowfins
Gulp air to fill air sac which is highly vascularized
Teleosts
Order: Anguilliformes
– Anguillidae: freshwater eels
– Jawed fish, catadromous
Order: Clupeiformes
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Clupeidae: herrings/shad
Threadfin and gizzard shad (Dorosoma)
Alewife and American shad (Alosa)
Planktivorous
Marine, anadromous, can live in freshwater
Blocked by dams, introduced as prey
Teleosts
Order Cypriniformes
– Cyprinidae: minnows and carp
Most diverse family (>2,000 species; 286 in N. A.)
57 species in WV
Many are small
Breeding coloration, tubercles, nest building
– Catostomidae: suckers
Bottom feeders, fleshy lips
Diverse in large rivers
Teleosts
Order Siluriformes
– Ictaluridae: N.A. catfishes, bullheads,
madtoms
Barbles
Largest freshwater fish family entirely indigenous
to N. America
Economically important: fishing and farming
Pylodictis olivaris
Teleosts
Order Esociformes
– Esocidae: Pikes (Esox)
Lie-in-wait predator
4 species, games fishes
Chain Pickerel, Esox niger
Teleosts
Order Salmoniformes
– Salmonidae: salmon, trout, char, whitefish
3 species in 3 genera
Oncorhynchus: Pacific salmon and western trout
O. mykiss: rainbow trout (steel head)
Salmo trutta: brown trout
Salvelinus fontinalis: brook char
Strong “homing” tendencies
Introduced widely
Cold water stenotherms
Teleosts
Order Cyprinodontiformes
– Fundulidae: killifishes
– Poeciliidae: livebearers, topminnows
Internal fertilization (gonopodium), live birth
Guppies, Gila topminnow and mosquito fish
– Cyprinodontidae: pupfishes
Most are endangered
Estuarine in origin
Desert pupfish: endemic to desert spring
environments as water dried up over geologic time
Teleosts
Order Gasterosteiformes
– Gasterosteidae: sticklebacks
Territorial nest builders, elaborate courtship
– Cottidae: sculpins
Large pectoral fins
No swim bladder
Cottus: freshwater sculpins
– cool-cold water streams
– Bottom dwelling invertivore
Cottus bairdi
Teleosts
Order Perciformes
– Moronidae : temperate basses
Morone saxatilis: striped bass: anadromous
Economically Important
Teleosts
Order Perciformes
Pomoxis nigromaculatus
– Centrarchidae: sunfishes, black basses
Second largest fish family indigenous to N.A.
Sexually dichromatic
Hybridize
Economically important
Lepomis: sunfish
Pomoxis: crappie
Micropterus salmoides
Micropterus: black bass
Pumpkinseed, Lepomis gibbosus
Lepomis cyanellus
Teleosts
Order Perciformes
Etheostoma blennioides
– Percidae: perches, walleye, darters,
saugers
Brilliant colors in darters
Darters are benthic invertivores
Economic importance of walleye, perch
– Channidae: snakeheads
Voracious predators, “swim” over land
Northern Snakehead (Channa argus)
http://www.dnr.state.md.us/fisheries/fishingrepo
rt/snakehead.html
Sander vitreus