Fish of the day Class Osteichthyes Northern Pike Class ... · Class Osteichthyes Division Teleostei Order Lampridiformes Family Regalecidae-Circumtropical, deep, rare, 'sea serpent'-Cartilaginous

ICHTHYOLOGY Lecture 16

NEXTBACK T O BEGINNINGLAST

Fish of the day...by Frank Nemeth

Class OsteichthyesOrder PerciformesFamily CichlidaeNeolamprus signatus



Fish of the day...by John Maples

Northern PikeClass: OsteichthyesOrder: EsociformesFamily: EsocidaeEsox lucius







2 Fish of the day...OarfishRegalecus glesneClass OsteichthyesDivisionTeleosteiOrderLampridiformesFamilyRegalecidae

-Circumtropical, deep, rare, 'seaserpent'-Cartilaginous mouth-no teeth orswimbladder-eats krill, up to 600 lbs.-longest bony fish-up to 56 feet!!!



THANKS GUYS!!



3Lentic-still waterLotic-moving water

Lentic systems-Lakes

All B&W figs from J.S.Diana-Biology and Ecologyof Fishes, 1995

Typical distribution -• bass and bluegills in

Epilimnion• perch and pike in

thermocline• trout in hypolimnion• sympatric species

separated by thermalbarrier

Winter

Fall or S prin g

Summer



4Oligotrophic lakes• deep, V-shaped• low nutrients, clear, blue• low primary production• low decomposition• low sedimentation• good stratification• "young"• Lake Tahoe

Eutrophic lakes• shallow, bowl shaped• high nutrients• high primary production• high decomposition• high sedimentation• poor stratification• "old"• Lake Erie before zebra mussel



5Invertedpyramid due toshort lifetime ofplankton

shoreline

Noticeimportance ofdetritus



6 If fish in lakes seem to overlap inniche-usually not in more than one aspectof niche

Alewife

Trout perch

Smelt

erch

1=complete overlap0=no overlapA=adultY=young



7 E.E. Werner and D.J. Hall-bluegill experiments in ponds atKellogg Field Station -1970s

Greens competitively superior findingzooplankton typical of that living onvegetation

Green Pumpkinseed Bluegill



Dry weight of fish

8 Removed vegetation from a pond and placedequal amounts of each fish species in each oftwo ponds (one with-one without vegetation)

Greens still looking for prey typical of vegetation, while bluegillsmake the switch more completely-even so Greens win overbluegillsPumpkinseed win overall in nonveg-never were looking for it



9Based on these resultsmade predictions-Each species shouldailor foraging tactics

based on their skills andhow they grow bestAll grow best feeding onzooplankton invegetation, butPumpkinseed also doeswell in open water-i tshould move out ofvegetation firstcompetition)

Then bluegillsGreens never move out ofvegetation



10 Can only explain results if abundanceof food declines through season(causing competition)-and it does



11 Bluegill and pumpkinseed both leavevegetation-grow at equivalent rates in vegetation-pumpkinseed does better in open water (betterbenthic feeder)



12Great set of experiments, butcan't be taken too far

• ponds aren't lakes

• winter might be bottleneckfor all competing species

• what about largemouth?



13

Lotic systems-sculpin anddace in a stream-dacedownstream,sculpinupstream



14

Where theyoverlap, sculpin indeeper fast water,dace in moreshallow fast water



15 Predation and Role of Refuge in BassOptimal foragingN.R. Glass, 1971

Largemouth bass preyingupon bluegill-increase available refuge-how does that changecapture success?



16

1=no pegs2=85 p/m^23=1854=370



17 Savino and Stein (OSU) repeated experimentwith more realistic refugia (1982)



18

Bluegills spendmore timeschooling if bassaround and ifrefugia absent

Documents

Fish of the day Class Osteichthyes Northern Pike Class ... · Class Osteichthyes Division Teleostei Order Lampridiformes Family Regalecidae-Circumtropical, deep, rare, 'sea serpent'-Cartilaginous