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Seahorses

Jienne Al-Haideri, Seema Patel, Chithra Rajasekaran & David Yang . Seahorses. Introduction Overview of Seahorses Morphology and Behavior brood pouches, snout, body, tail, dorsal fins feeding, Sexual dimorphism Conservation Concerns Future Directions Summary & Conclusions Q & A. Agenda.

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Seahorses

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  1. Jienne Al-Haideri, Seema Patel, Chithra Rajasekaran & David Yang Seahorses

  2. Introduction Overview of Seahorses Morphology and Behavior brood pouches, snout, body, tail, dorsal fins feeding, Sexual dimorphism Conservation Concerns Future Directions Summary & Conclusions Q & A Agenda

  3. Seahorses Order: Gasterosteiformes Family: Syngnathidae Genus: Hippocampus Ancient Romans/Aristotle Size Range Marine 30-120 species Introduction

  4. Highly involved male parental care Completely enclosed brood pouch Function: Osmoregulation, nutrition, respiration, incubation site. Comparisons Pipe fishes: simple, inverted pouches. Brood Pouches

  5. Male Reproduction

  6. Sexual Dimorphism • Males/females differ in their external anatomy

  7. Monogamous (mate for life; unlike most fish) • Dimorphism evolved from sexual selective pressures • Ex: longer trunks in females accommodate developing ovaries • longer tails in males aid in courtship (tail grabbing) and gestation (brood pouches) • Note: Seahorses still maintain traditional sex roles

  8. Sit-and-wait predators Camouflage Rely on site (independently moving eyes) Feed primarily on mobile prey—mainly crustaceans Evolved from straight bodied swimmers (pipe fish) Pivot feeding (2 step process) Feeding

  9. S-shaped body increases strike distance • Main point: S-shaped body and sit-and-wait strategy evolved for better feeding

  10. elongated snout various snout dimensions depending on species snout length/width differences with age pivots head to lessen distance from their snout to the prey lift angles allow for a greater distance to be covered by the mouth Snout Short-snouted Seahorse  Leafy Seadragon

  11. Anatomy of a Seahorse Head:

  12. lack scales Body Armor: thin layer of skin covering several bony plates Trunk rings and coronet Coronet: "crown" structure positioned at head (equivalent to human thumbprint) Camouflage used as a defense mechanism and predatory strategy (ex. Dragon Seahorse) Armor makes them unappetizing prey Body Covering

  13. Specialized prehensile (grasping) tail Evolution of bent tail Change in regulation of growth and development Daily life Attached to algae and corals Social Behavior Tail

  14. Highly specialized oscillations High frequency median fin propulsion (unusual) Habitat selected for high degree of maneuverability Complex, obstacle-strewn environment Dorsal Fin

  15. Simultaneous prey and predator Economic value Chinese medicinaluses 50% decline in naturalpopulations Vulnerable due to behavior Live in endangered environments By-catch (e.g., Shrimp Trawlers) Conservation Issues

  16. Evolutionary history is still controversial Mystery of bending tail evolution Phylogenetic relationships are poorly understood Difficult to culture seahorses due to lack of information/data Indicator species? Future Research and Directions

  17. Anthropogenic pressures need to be lifted Overexploitation in target fisheries Threats from habitat degradation Exceptionally unique Unique reproduction (male pregnancy) Drastically changed the fish body plan Vertical swimming style They need protection! Dramatic declines worldwide Biggest predator is man Summary

  18. Questions?

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