Lesson 1

• Acipenseriformes


  Actinopterygii

  Subclass Chondrostei

  Includes Sturgeons & paddlefishes

  Cartilaginous dermal bones

  Swim bladder

  Protrusible jaws
• Polypteriformes


  Acrinopterygii

  Subclass Chondrostei

  Includes bichirs and reedfishes

  Heavily armored

  Obligate air breathers (Scales deform during exhalation to help bring in air for inhalation)
• Amiiformes


  Subclass Neopterygii

  Includes bowfin

  Has thin scales like teleosts

  Uses suction feeding

  Has heterocercal tail

  Retains the following ancestral neopterygian characteristics

  • Heavy scales
  • Dorsal swim bladder for respiration & buoyancy
• Semionotiformes


  Subclass Neopterygii

  Includes gars

  Have ganoid scales

  Use teeth for grasping

  Retains the following ancestral neopterygian characteristics

  • Heavy scales
  • Dorsal swim bladder for respiration & buoyancy
• How much of all living species make up infraclass Teleostei?

  95%
• What are the major trends seen in Teleosts?

  Reduction in bony elements

  • Fewer vertebrae
  • Fewer bones in the skull
  • Fin ray reduction in caudal and pectoral fins

  Pectoral and pelvic fins change body position

  Caudal fin modifications

  Swimbladder modifications

  Improvements in feeding apparatus

  
• What are the end results of teleost trends?

  Fast & maneuverable

  Reduced armor

  Efficient prey capture

  Efficient and diverse prey processing
• What are some characteristics of teleosts?

  Operculum is made fo 4 bones

  Homocercial tail is supported by uroneurals

  Either have cycloid scales, ctenoid scales, or no scales

  Ossified, lightweight vertebrae due to acellular bone

  Swim bladder

  Movable maxilla and premaxilla

  • Premaxilla principal bones in upper jaw

  Fins are highly maneuverable with rays and spines

  Variable body shapes

  
• What are some features of freshwater fish reproduction?

  Oviparous

  Relatively few large, yolk-rich demersal eggs

  Often use nests, are attached to their parent, or are cared for

  Often hatch with residual yolk sac

  • Fish with residual yolk sac are called fry

  
• What are some features of saltwater fish reproduction?

  Large numbers of small, buoyant, transparent eggs

  Larve small, little yolk reserve remains

  Often goes through indirect development

  
• What are some interesting adaptations of sex in teleosts

  Protandry

  Protgyny

  Hermaphroditism

  Gynogenesis

  Hybridogenesis
• Protandry


  Fish starts as a male but changes to a female under certain conditions

  Seen in anemone fish

  
• Protgyny


  Fish starts as a female and changes to a male over time

  Seen in wrasses, including the bluehead wrasse

  
• Hermaphroditism


  Fish has both male and female gametes

  Seen in hamlets like the Sargent Major

  
• Gynogenesis


  eproduction that requires the presence of sperm without the actual contribution of its DNA for completion
• Hybridogenesis


  selective transmission of one of the parental genomes, while the other one is renewed by mating with the corresponding species
• What are some notable features of teleost ecology

  Highly adaptable

  • Found in deep sea and high mountain lakes
  • Requires many physical and physiological adaptations

  Diversity of feeding ecology

  • Range from herbivory to corallivory to apex predators
• What is notable about the conservation of freshwater fishes

  40% of fish species are freshwater species

  • 800 native species in the USA
  • 61 are extinct
  • 40% are imperiled

  Some challenges they face include...

  • Alteration to habitat
  • Pollution
  • Damming
  • Draining
  • Channelization
  • Stream Diversions

  
• What is notable about the conservation of marine fishes?


  Overfishing is causing the collapse of many fisheries

  • George banks fishery virtually closed in the 1990s and after rebounding it is being fished again 20 years later but...
  • Fish are smaller
  • Population sizes are smaller
  • Populations are already declining again

  Interaction with reproductive biology

  • High reproductive potential (early maturity + high fecundity) = overharvest resistant
  • Cod, haddock, flounder
  • Low reproductive potential (late maturity/long life + low fecundity) = vulnerable to overharvest
  • Most predatory fish
• 8 of 10 predatory fish with generation times > 6 yrs = IUCN  categories of Vulnerable, Endangered, or Highly Endangered
• How does fish farming interact with conservation

  Farmed fish are more likely to introduce parasites, disease, or pollution to wild populations

  Genetic imput and constraints cause issue for wild populations