BuoyancyPowerPoint PresentationSlide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35BuoyancySpecific gravity:fresh water 1.0sea water 1.026fats, oils 0.9-0.93tissues 1.05-1.1cartilage 1.1bone, scales 2.0total fish body 1.06-1.09Strategies to deal with sinking:1. reduce body weight - reduce heavy materials – cartilage in place of bone– deepsea fishes reduce bone and muscleSpecific gravity:fresh water 1.0sea water 1.026fats, oils 0.9-0.93tissues 1.05-1.1cartilage 1.1bone, scales 2.0total fish body 1.06-1.09Strategies to deal with sinking:1. reduce body weight - reduce heavy materials - add lighter materials - strategy used by most sharks, a few teleostslipids (specific gravity ~0.90)squalene (especially in the liver) ~0.86 - Mola mola uses ‘fresh’ water (lighter than sea water)Specific gravity:fresh water 1.0sea water 1.026fats, oils 0.9-0.93tissues 1.05-1.1cartilage 1.1bone, scales 2.0total fish body 1.06-1.09Strategies to deal with sinking:1. reduce body weight - reduce heavy materials - add lighter materials - strategy used by most sharks, a few teleostslipids (specific gravity ~0.90)squalene (especially in the liver) ~0.86 - Mola mola uses ‘fresh’ water (lighter than sea water)using fat alone requires ~ 48% of body volume as fat(e.g., Salmoniformes – siscowet lake trout)Strategies to deal with sinking:1. reduce body weight2. add buoyancy compensating organ (gas bladder) - physostomus (open to the outside) - physoclistous (sealed)Strategies to deal with sinking:1. reduce body weight2. add buoyancy compensating organ (gas bladder) - physostomus (open to the outside) - physoclistous (sealed)BUT: pressure increases 1 atm for every 33’ depth (10 m)Strategies to deal with sinking:1. reduce body weight2. add buoyancy compensating organ (gas bladder) - physostomus (open to the outside) - physoclistous (sealed)BUT: pressure increases 1 atm for every 33’ depth (10 m)fish do not usually change depth to bring about more than a 25% change in gas bladder volume - change from 90 to 100m decreases volume by only 10% - change from 20 to 30 m decreases by about 25%Strategies to deal with sinking:1. reduce body weight2. add buoyancy compensating organ (gas bladder) - physostomus (open to the outside) - physoclistous (sealed) ~ 2/3 of all teleostsincrease partial pressure of gas in bloodallow passive diffusion via rete mirableGas bladder:lactic acid in blood circulating around bladder releases oxygen (Root effect)Cells convert glucose to lactic acidStrategies to deal with sinking:1. reduce body weight2. add buoyancy compensating organ (gas bladder) - physostomus (open to the outside) - physoclistous (sealed) ~ 2/3 of all teleostsincrease partial pressure of gas in bloodallow passive diffusion via rete mirabledeepsea fishes – higher pressures – longer capillariesgas resorbed via simple diffusion, expelled via gillsStrategies to deal with sinking:1. reduce body weight2. add buoyancy compensating organ (gas bladder)3. generate lift - heterocercal tail - planing surfaces – pectoral fins, entire bodyScorpaeniformes – sea moth, flying gunard Pleuronectiformes - flounderStrategies to deal with sinking:1. reduce body weight2. add buoyancy compensating organ (gas bladder)3. generate lift4. avoid the problem – live on the bottom, use lift as neededScorpaeniformes - sculpinRespirationRespirationavailability of O2 in water varies with - temperature- productivity- BODorigin of fishes in warm Tethys Sea….Respiration• lungs – lungfishes (Subclass Dipnoi – Ceratodontiformes, Lepidosireniformes)- including obligate air breathersRespiration• lungs – lungfishes• modified gas bladder – bichirs, bowfin, gars(Polypteriformes, Lepisosteiformes, Amiiformes)Respiration• lungs – lungfishes• modified gas bladder – bichirs, bowfin, gars• “normal” gills – most teleostsbuccopharyngeal cavityparabranchial cavityRespiration• lungs – lungfishes• modified gas bladder – bichirs, bowfin, gars• “normal” gills- respiratory pump, or- ram ventilationRespiration• lungs – lungfishes• modified gas bladder – bichirs, bowfin, gars• “normal” gills• modified gills- gill filaments tend to stick together in air- tough filaments handle temporary exposure to aire.g. walking catfishRespiration• lungs – lungfishes• modified gas bladder – bichirs, bowfin, gars• “normal” gills• modified gills• skin - reedfish – skin supplies 32% of O2 need despite ganoid scales - mudskipper (Periopthalmus) – 48% - eels (Anguilla) – 30-66% “eel fields”….Respiration• lungs – lungfishes• modified gas bladder – bichirs, bowfin, gars• “normal” gills• modified gills• skin - reedfish – skin supplies 32% of O2 need despite ganoid scales - mudskipper (Periopthalmus) – 48% - eels (Anguilla) – 30-66% • mouth – electric eel, carp• gut – PlecostomusRespiration• lungs – lungfishes• modified gas bladder – bichirs, bowfin, gars• “normal” gills• modified gills• skin - reedfish – skin supplies 32% of O2 need despite ganoid scales - mudskipper (Periopthalmus) – 48% - eels (Anguilla) – 30-66% • mouth – electric eel, carp• gut – Plecostomus• surface water - killifishCyprinodontiformesThermoregulationare fish “cold-blooded”?poikilotherms internal temperature varieshomeotherms internal temperature remains stableectotherms temperature is controlled externally endothermstemperature is controlled internallythermal strategiesectotherms – thermoregulate behaviorally - switch different forms of enzymes on and off - tend to have limited thermal ranges - alter cell membrane saturated:unsaturated fat ratio to maintain fluiditythermal strategiesectotherms – thermoregulate behaviorally - switch different forms of enzymes on and off - tend to have limited thermal ranges - alter cell membrane saturated:unsaturated fat ratio to maintain fluidityendotherms – thermoregulate physiologically- use rete mirable to conserve heat- red muscle next to spinal column to insulate heatthermal strategiesectotherms – thermoregulate behaviorally - switch different forms of enzymes on and off