MARINE FISHES WHY ARE THEY SO IMPORTANT TO

MARINE FISHES WHY ARE THEY SO IMPORTANT TO HUMANS?

SUBPHYLUM VERTEBRATA Ø IN PHYLUM CHORDATA Ø NOTOCHORD = SPINAL COLUMN Ø DORSAL HOLLOW NERVE CORD = SPINAL CORD AND BRAIN Ø POST ANAL TAIL Ø GILL POUCHES = GILLS OR LUNGS

FISHES Ø MAKE UP OVER HALF OF ALL VERTEBRATES Ø 3 CLASSES: AGNATHA, CHONDRICHTHYES, OSTEICHTHYES Ø HOW DO SOME FISH SURVIVE IN BELOW FREEZING CONDITIONS? (227)

AGNATHA (JAWLESS FISH) Ø MOST PRIMATIVE Ø CARTILAGENOUS SKELETON Ø FEED BY SUCTION AND EXTENDING A DENTAL PLATE WITH TEETH LIKE STRUCTURES Ø LACK PAIRED FINS AND SCALES Ø EEL LIKE

HAGFISH MOSTLY SCAVENGERS SOME FEED ON LIVE PREY (DENTAL PLATE) Ø FEED ON DEAD OR DYING FISH Ø MAY EAT FROM INSIDE OUT Ø BOTTOM DWELLERS (LIVE IN BURROWS) Ø PRODUCE SLIME THAT SUFFICAT PREDATORS Ø MONECIOUS OR DIECIOUS Ø EXTERNAL FERTILIZATION Ø

LAMPREYS Ø BREED IN RIVERS AND LAKES BUT SOME MOVE TO SEA AS ADULTS Ø LARVA MAY LIVE IN BURROWS FOR 3 -7 YEARS BEFORE METAMORPHOSIS INTO ADULT FORM Ø ATTACH TO FISH AND SUCK THEIR FLUIDS WITH DISK SHAPED MOUTH WITH TOOTH LIKE STRUCTURES

CHONDRICHTHYES (CARTILAGENOUS FISH) Ø SHARKS, SKATES, RAYS, CHIMERAS, RATFISH Ø SKELETON OF CARTILAGE Ø VENTRAL MOUTHS Ø DERMAL DENTICLES Ø CALLED LIVING FOSSILS

SHARK CHARACTERISTICS Ø PECTORAL FINS (BERNOLI’S PRINCIPLE) AND OILY LIVER FOR LIFT Ø GILLS NOT PROTECTED (GILL SLITS) Ø CONTINUE TO SWIM FOR OXYGEN AND LIFT (NURSE SHARKS EXCEPTION) Ø SOME HAVE HETEROCERCAL CAUDAL FIN FOR LIFT

OTHER SHARK CARACTERISTICS Ø NICTITATING MEMBRANE OVER EYE Ø ACUTE OLFACTORY SENSES DUE TO 2/3 OF CELLS IN BRAIN ARE USED FOR PROCESSING SMELLS Ø LATERAL LINE SYSTEM (TUBES THE LENGTH OF BODY WITH NEUROMAST CELLS THAT DETECT MOVEMENT) Ø AMPULLAE OF LORENZINI (DETECT ELECTRICAL CURRENTS)

DIGESTION Ø TAKES CHUNKS OF PREY, NO CHEWING Ø SPIRAL VALVE AIDS IN DIGESTION BY ADDING SURFACE AREA

OSMOREGULATION Ø RETAIN UREA TO MAINTAIN SOLUTE CONCENTRATION EQUAL OR GREATER THAN SEA WATER Ø RECTAL GLAND GILLS GET RID OF EXCESS SALT Ø SOME SHARKS CAN GO INTO RIVERS

REPRODUCTION Ø CLASPERS INSERT INTO CLOACA FOR INTERNAL FERTILIZATION Ø SHARKS MAY BE: Ø OVIPAROUS (LAY EGGS; MERMAIDS PURSE) Ø VIVIPAROUS (LIVE YOUNG) Ø OVOVIVIPAROUS (INTERNAL EGGS AND LIVE BIRTH)

LARGEST FISHES Ø WHALE SHARK (60 FT) Ø BASKING SHARK (50 FT) Ø BOTH ARE FILTER FEEDERS

RAYS VS. SKATES FLAT BODIED, BOTTOM DWELLERS (DEMERSAL) Ø GILL SLITS ON VENTRAL SIDE OF BODY Ø WING-LIKE PECTORAL FINS Ø STINGRAYS HAVE STINGING BARB AT BASE OF TAIL Ø ELECTRIC RAYS = UP TO 220 VOLTS WITH ORGANS ON HEAD Ø SKATES DON’T HAVE WHIP TAIL OR STING, AND HAVE WAVE-LIKE MOTION WITH PECTORAL FINS INSTEAD OF FLAPPING Ø

RATFISH AND CHIMARAS Ø HAVE SKIN OVER GILLS LIKE AN OPERCULUM Ø TAKE WATER THROUGH NOSTRILS AND OUT OF GILLS

OSTEICHTHYES (BONY FISH) Ø MOST FISH ARE BONY (98%); HALF OF ALL VERTEBRATES Ø BONY SKELETON Ø CYCLOID (ROUND) SCALES Ø OPERCULUM (GILL COVER) Ø TERMINAL MOUTHS Ø SWIM BLADDER (PRESSURE AND LIFT) Ø MANUVERABLE FINS

SUBCLASS SARCOPTERYGII (LOBE-FINNED FISHES) LUNG FISH (HAVE PRIMATIVE LUNGS INSTEAD OF SWIM BLADDER) Ø COELACANTHS (THOUGHT TO HAVE BEEN EXTINCT UNTIL DISCOVERED OFF THE COAST OF MADAGASCAR) Ø COELACANTHS ARE THOUGHT TO BE A LINK BETWEEN FISH AND AMPHIBIANS BECAUSE OF THEIR LOBE FINS (HOMOLOGOUS STRUCTURES) Ø

SUBCLASS ACTINOPTERYGII (RAY FINNED FISH) Ø HAVE RAY FINS AND COMPRISE ALL FISH OTHER THAN LUNG FISH AND COELACANTHS Ø CONTAIN A SWIM BLADDER Ø MOST DIVERSE AND NUMEROUS SUBCLASS OF FISH

BODY SHAPE Ø DIRECTLY RELATED TO THE HABITAT THE FISH LIVES IN Ø FAST FISH ARE HYDRODYNAMIC (FUSIFORM BODY SHAPE; TUNA AND MARLIN)

BODY SHAPE Ø REEF FISH ARE BUILT TO TURN AND MANUVER (LATERALLY COMPRESSED LIKE BUTTERFLY FISH AND TANG) Ø FLAT FISH ARE BUILT FOR BOTTOM DWELLING (FLOUNDER) Ø SOME FISH ARE SHAPED FOR CAMO. (STONE FISH, PIPE FISH)

COST OF TRANSPORT Ø FRICTIONAL DRAG (CAUSED BY SURFACE OF FISH) Ø FORM DRAG (CAUSED BY DIAMETER OF FISH) Ø TURBULANCE (CAUSED BY MOVEMENT THROUGH WATER) Ø THE LESS FISH HAVE OF THE ABOVE FACTORS = LESS ENERGY USED

ASPECT RATIO Ø (CAUDAL FIN HEIGHT/FIN AREA)2 Ø CAUDAL FIN = TAIL FIN Ø HIGHER THE RATIO THE FASTER THE FISH Ø FASTEST TO SLOWEST: FORKED, LUNATE, HETEROCERCAL, TRUNCATE, ROUNDED Ø LIST 2 FISH PER FIN.

LOCOMOTION Ø IDEAL BODY FOR SPEED IS A FISH WHOS LENGTH IS 4. 5 TIMES GREATER THAN ITS DIAMETER Ø LOW COST OF TRANSORT COMBINED WITH HIGH ASPECT RATIO = FAST Ø “S” WRIGGLE IS BASIC FISH MOTION Ø IT IS ACHIEVED MYOMERES (W SHAPED MUSCLES THAT YOU LIKE TO EAT)

FISH FINS Ø ANAL, DORSAL, PELVIC, AND PECTORAL ARE TYPICALLY USED FOR STABILITY Ø CAUDAL FINS ARE USED FOR THRUST Ø RAYS AND SKATES USE PECTORAL FOR TRUST; SEA HORSES USE THEIR DORSAL FINS Ø REEF FISH TYPICALLY ONLY MOVE THEIR FINS TO MOVE NOT MYOMERES

PHYSOCLIST VS. PHYSOSTOMOUS SWIM BLADDER Ø PHYSOCLIST SWIM BLADDER RECEIVES GASES FROM THE BLOOD Ø PHYSOSTOMOUS SWIM BLADDER RECEIVES GASES FROM A CONECTIVE TUBE THAT RUNS FROM THE MOUTH TO THE BLADDER

COLORATION CHROMATOPHORES ARE COLOR CELLS (SACKS OF PIGMENT) Ø IRIDOPHORES REFLECT LIGHT (CRYSTALS INSIDE) Ø CAUSE FISH TO LOOK SHINY Ø COLORS ADVERTISE REPRODUCTION, DANGER, BAD TASTE (POSTER COLORS) Ø REEF FISH HAVE CRYPTIC COLORATION Ø OPEN WATER FISH = OBLITERATIVE COUNTER SHADING Ø

FEEDING Ø MAKE A LIST OF VARIOUS TYPES OF FISH AND THEIR FEEDING METHODS. Ø WHAT IS FILTER FEEDING? Ø WHAT ARE GILL RAKERS AND HOW ARE THEY USED? Ø WHAT DOES MOUTH POSITION HAVE TO DO WITH THE TYPE OF FOOD EATEN BY FISH?

SCHOOLING Ø ABOUT 4000 SPECIES SCHOOL AS ADULTS Ø KEEP A CONSISTENT DISTANCE USING LATERAL LINE Ø LATERAL LINE IS A SERIES OF FLUID FILLED PITS THAT SENSE PRESSURE CHAGES IN THE WATER Ø WHY DO FISH SCHOOL?

REPRODUCTION Ø CARTILAGENOUS FISH HAVE INTERNAL FERTILIZATION: CLASPERS ARE INSERTED INTO FEMAL CLOACA Ø CLOACA IS A COMMON OPENING FOR WASTE AND REPRODUCTION Ø SPAWNING IS A FISHES FERTILE TIME Ø SEX HORMONES READY THE GAMETES AND FISH FOR SPAWNING

HERMAPHRODITISM Ø SOME ARE HERMAPHRODITES Ø SOME HAVE SEX REVERSAL TRIGGERED BY HORMONES TURNED ON BY ENVIRONMENTAL FACTORS, LIKE LOSS OF DOMINANT MALE OR MATURITY TO A CERTAIN AGE OR SIZE

QUESTIONS Ø NAME AND DESCRIBE FIVE DIFFERENT REPRODUCTIVE STRATEGIES OF BONY FISH (PG 244 -246)

MIGRATION Ø RELATED TO FEEDING AND REPRODUCTION Ø ANADROMOUS = FRESH (BREEDING) AND SALT (MOST OF LIFE) ; SALMON Ø CATADROMOUS = SALT (BREEDING) FRESH (MOST OF LIFE); EEL

QUESTIONS Ø HOW DO THEY NAVIGATE IN THE OCEAN? Ø DESCRIBE THE LIFE CYCLE OF THE SALMON. Ø DESCRIBE THE LIFE CYCLE OF THE EEL. COMPARE THE AMERICAN AND EUROPEAN EELS.