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elasmo-research/education/shark_profiles/hammerhead_faq.htm

http://www.elasmo-research.org/education/shark_profiles/hammerhead_faq.htm. Hammerhead sharks ( 8 species known) Sea of Cortez has the scalloped hammerhead ( Sphryrna lewini) School around seamounts Slow reproductive rate: females mature at 15 yrs, 12 month

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elasmo-research/education/shark_profiles/hammerhead_faq.htm

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  1. http://www.elasmo-research.org/education/shark_profiles/hammerhead_faq.htmhttp://www.elasmo-research.org/education/shark_profiles/hammerhead_faq.htm Hammerhead sharks (8 species known) Sea of Cortez has the scalloped hammerhead (Sphryrna lewini) School around seamounts Slow reproductive rate: females mature at 15 yrs, 12 month gestation, 1 year off between pregnancies Fished for food and sport

  2. http://www.elasmo-research.org/education/shark_profiles/hammerhead_faq.htmhttp://www.elasmo-research.org/education/shark_profiles/hammerhead_faq.htm • Why the hammerhead shape? • spreads out sensory ability (electric, olfactory) • (disadvantages: prevents jaw protusion & 3D vision) • -use the hammer to pin down stingrays and eat them • (stingray spines often found in heads)

  3. Figure 8.1

  4. Three groups of fishes Cartilagenous fish (Chondricthyes) Jawless fish (Agnatha) Bony Fish (Osteichthyes) lamprey http://www.germantown.k12.il.us/html/Fishy.html

  5. Class Osteichthyes (Bony Fish) - Dominant vertebrate in the sea - 26,000 species (96% of all fish, 50% of all vertebrates) http://www.germantown.k12.il.us/html/Fishy.html

  6. Figure 8.8

  7. Figure 8.14

  8. How to cope with salt in seawater (tend to lose water) • Sharks (blood = seawater) • - concentrate urea • excrete salt in urine, • feces, rectal gland Bony fish (blood<seawater) -kidneys conserve water -excrete salts in urine, feces, gills, skin

  9. Figure 8.16

  10. Figure 8.9 Streamlined (fusiform) Fast-open water Live in vegetation/ coral Flattened top to bottom - Bottom dweller Flattened side to side- bottom or coral reef Slow - reef Trunklike or round - slow moving, reef

  11. Figure 8.13

  12. Maintaining buoyancy Gas-filled swim Bladder, pectoral fins freed for other uses- great diversity of forms Large oily live, light skeleton, pectoral fins for stability

  13. modes of swimming Undulation flex caudal region move fins tail fin ( eels) (tuna) surgeonfish boxfish

  14. Figure 8.22 Salmon Anadromous = Spend lives at sea feeding, return to rivers to breed: Magnetic field and smell of home rivers Skipjack tuna Tropical species that travels to temperate water to feed. Halfway across globe each year.

  15. Figure 8.22 Conservation threats Polluted rivers, dams Water harvested Introduced species of farmed salmon

  16. Catadromous - breed at sea, migrate into rivers to grow (16 spp freshwater eels)adults spawn and die in Sargasso Sea / larvae in plankton 1 yr+/ metamorphose into juveniles / grow and mature in rivers

  17. Why do fish school?

  18. “selfish herd theory”(middle is safest place to be)

  19. Buoyancy - how to regulate Cartilagenous fish (sharks, rays, chimaeras) -large oily liver, light skeleton - pectoral fins needed for stability/steering Advantages: rapid changes in depth possible Bony fish • Swim bladder (gas-filled sac above intestine) Advantages: freed up pectoral fins for other uses

  20. Strange reproductive practices of fish • Hermaphrodites • Sex change (born one sex, become the other) Large fish in harems are often sex-change males Large fish in non-harem species are often sex-change females • Parasitic males • “Sneaker” males that look like females • Sex-role reversal (male pregnancy in seahorses) • Males often do parental care in fish

  21. http://www.geocities.com/thesciencefiles/angler/fish.html Anglerfish adaptations for deep water habitat:

  22. http://www.geocities.com/thesciencefiles/angler/fish.html Anglerfish adaptations for deep sea (food and mates scarce) sit and wait predatory behavior bioluminescent lure parasitic males - once males encounter female, they don’t leave

  23. Rainbow wrasse Thalassoma lucasanum Two types of males Two types of reproduction. 1) Females (yellow/red lateral stripes) 2) Primary males (look like females) 3) Terminal males (blueheads) - born female, turn into males http://www.oceanoasis.org/fieldguide/thal-luc.html

  24. Rainbow wrasse T. lucasanum Two types of reproduction Broadcast spawning Many males and females rush to surface and release gametes 2) Harems: one terminal male guards group of females and mates with them individually. Death of secondary male- large female turns into new terminal male http://www.oceanoasis.org/fieldguide/thal-luc.html

  25. Mass spawning of the rainbow wrasse Thalassoma lucasanum

  26. Barred serrano • Serranus psitticinus • Sea of Cortez • Simultaneous • hermaphrodite • (can act as male or • female at any time) • dominant male • in harem mates with • “females”. Serranus annularis Caribbean Orange back basslet http://www.qualitymarineusa.com/fish/basslets.html#top

  27. Lecture ended here.

  28. http://www.cnn.com/TECH/science/9812/11/seahorses.yoto/ • Male pregnancy in seahorses • Placenta • Long-term pair bond • Daily dance of pair

  29. http://www.cnn.com/TECH/science/9812/11/seahorses.yoto/ Conservation of Sea Horses 20 million caught each year - 95% chinese medicine - 5% aquarium trade 32 species (threatened status)

  30. Coelocanth (lobe-finned fish)

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