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Welcome to Zoo 511Ecology of Fishes

1Todays outlineIntroductionsReview syllabusExpectations and goalsLecture Fish AnatomyLab fish dissections

Walleye

Bluegill

Diversity of fishes3Take this fish and look at it.

4What do you think:What is a fish?

What could we learn from inspecting and dissecting a fish? (Think about what you learned already)5What is a Fish?Poikilothermic body temperature is identical to surrounding waterChordates have developmental characteristics of all vertebratesAppendages developed as finsChief respiratory organs are gillsBody generally covered with scales

A fish is an aquatic vertebrate with gills and with limbs in the shape of fins (Nelson 1994)

There are >30,000 fish species, so there are exceptions to these general characteristics.

6Fish anatomyForms the basis for most identificationAnatomy can teach us about ecology & evolutionary relationships

Mississippi paddlefish

PorcupinefishOcean sunfish

Leafy seadragonWhy dissect fish?Evolution / phylogenyPhysiologyPathology/diseaseGut contentsOtoliths (aging)Fecundity/fitness

Todays Fish GoalsPractice skills of close observationLearn basic external and internal anatomy of fishesPractice using a dichotomous key to ID fishBegin thinking about how structure relates to function

Muskellunge

Flounder9DorsalAnatomical terminologyVentralPosterior or caudalAnteriorLateralLateralUsed for relating different parts.Eye is posterior to the mouthConversely the mouth is anterior to the eye10External Anatomy

Sail fish (Istiophorus platypterus)

American eel (Anguilla rostrata)FinsMouthScales

White sucker(Catostomus commersonii)

River hatchetfish (Gasteropelecus sternicla )

Longnose gar(Lepisosteus osseus)Great white shark(Carcharodon carcharias)11FinsDorsalAnalPelvicPectoralAdiposePectoralPelvicCaudalAnal12Caudal Fins

HeterocercalTip of vertebral column turns upwardEpicercal: dorsal lobe larger (sturgeon)Hypocercal: ventral lobe longer (flying fish)

ProtocercalExtends around vertebral columnEmbryonic fish; hagfish

HomocercalVertebral column stops short of caudal fin, which is supported by bony raysSymmetricalDerived fishes

Diphycercal3 lobed; lungfish and coelacanthVertebral column extends to end of caudal fin, dividing into symmetrical parts

14Spines vs. rays

Bluegill (Lepomis macrochirus)15SpinesRigidNever segmentedOften for defense

RaysFlexibleOften branchedMainly for support

Fisheries ecologists use both spines & rays for identification and aging!16External Anatomy

Sail fish (Istiophorus platypterus)

American eel (Anguilla rostrata)FinsMouthScales

White sucker(Catostomus commersonii)

River hatchetfish (Gasteropelecus sternicla )

Longnose gar(Lepisosteus osseus)Great white shark(Carcharodon carcharias)17

Mouth placement

superiorterminalInferior (sub-terminal)18External Anatomy

Sail fish (Istiophorus platypterus)

American eel (Anguilla rostrata)FinsMouthScales

White sucker(Catostomus commersonii)

River hatchetfish (Gasteropelecus sternicla )

Longnose gar(Lepisosteus osseus)Great white shark(Carcharodon carcharias)19Scale typesPlacoidGanoidCycloidCtenoid

Placoid: sharks and rays

Riblets decrease drag.

Ganoid: bowfin, paddlefish, gar, sturgeonArmor-like plates for protection21Cycloid and Ctenoid: most bony fishes (teleosts)

Overlapping = Flexibility, reduced dragBoth grow in concentric rings

Cycloid: smooth outer edge, soft-rayed fish (e.g., salmon)Ctenoid: toothed outer edge, spiny fish (e.g., bass)22

Scutes are a modification of scales

23Modified placoid scales

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Snakehead

FISH WITH TEETH

Not all teeth are pointy!i.e. Vomerine teeth

MuskieWalleyeBurbotLongfinned Eel Chinook Salmon

Pacu25

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Gills and Gill Rakers

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Structure and function

30Barbels: nothing is easier to identify!!

Yellow BullheadBrown BullheadBurbotBurbot

Lake Sturgeon31Lateral line

Sensory organLine of electroreceptor cellsUsed to detect vibrations

MaxillaPremaxillaDentary33Measure anatomy to do ecological studies

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Internal anatomy35

Swim bladderOvaryHeartLiverStomachIntestineFat depositsKidney36Red vs. white muscleRed (aerobic)High capillary densityAllows adequate oxygenationMetabolizes lipids in mitochondria

White (anaerobic)Converts glycogen to lactateLactic acid build up

Cross-section of White Shark Caudal Peduncle37Resources for Fish IDBecker Key (ebook available)WiscFishFishBase (global)

Get started!You need:A partnerA fishSome tools The worksheet