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 – 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: black bass Micropterus salmoides
Lepomis cyanellus
Pumpkinseed, Lepomis gibbosus
Teleosts
Order Perciformes – 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
Etheostoma blennioides Sander vitreus