ICHTHYOLOGY Lecture 16
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Fish of the day...by Frank Nemeth
Class OsteichthyesOrder PerciformesFamily CichlidaeNeolamprus signatus
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Fish of the day...by John Maples
Northern PikeClass: OsteichthyesOrder: EsociformesFamily: EsocidaeEsox lucius
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ICHTHYOLOGY Lecture 16
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ICHTHYOLOGY Lecture 16
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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!!!
ICHTHYOLOGY Lecture 16
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THANKS GUYS!!
ICHTHYOLOGY Lecture 16
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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
ICHTHYOLOGY Lecture 16
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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
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5Invertedpyramid due toshort lifetime ofplankton
shoreline
Noticeimportance ofdetritus
ICHTHYOLOGY Lecture 16
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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
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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
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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
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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
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10 Can only explain results if abundanceof food declines through season(causing competition)-and it does
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11 Bluegill and pumpkinseed both leavevegetation-grow at equivalent rates in vegetation-pumpkinseed does better in open water (betterbenthic feeder)
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12Great set of experiments, butcan't be taken too far
• ponds aren't lakes
• winter might be bottleneckfor all competing species
• what about largemouth?
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13
Lotic systems-sculpin anddace in a stream-dacedownstream,sculpinupstream
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14
Where theyoverlap, sculpin indeeper fast water,dace in moreshallow fast water
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15 Predation and Role of Refuge in BassOptimal foragingN.R. Glass, 1971
Largemouth bass preyingupon bluegill-increase available refuge-how does that changecapture success?
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16
1=no pegs2=85 p/m^23=1854=370
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17 Savino and Stein (OSU) repeated experimentwith more realistic refugia (1982)
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18
Bluegills spendmore timeschooling if bassaround and ifrefugia absent
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