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Sea Urchins

Sea Urchins. Rosalie Flores Marine Aquaculture. Taxonomy of types cultured. Echinoderm ( echino =spiny, derms = skins) Paracentrotus lividus – European Strongylocentrotus droebachiensis (green sea urchin) – Japan Evechinus chloroticus (kina) – New Zeland.

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Sea Urchins

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  1. Sea Urchins Rosalie Flores Marine Aquaculture

  2. Taxonomy of types cultured • Echinoderm (echino=spiny, derms = skins) • Paracentrotuslividus– European • Strongylocentrotusdroebachiensis (green sea urchin) – Japan • Evechinuschloroticus (kina) – New Zeland

  3. Economic importance, market price $ and locations • Sea urchins are important for roe harvesting. • Their roe (gonads) are a seasonal product and only acceptable to the market during a window of a few months ( before spawning period of urchins specific to that region). • In the U.S. and Japan they are retailed for about $6 for two tongues or $35 to $40/ lb. • In Japan – “uni” is sushi containing roe (delicacy)

  4. Life cycle • Pluteus Larva stage - gut, mouth and skeleton formed. • Larva drifts in water column for 3wks-3mos, eating until they are big enough to settle on seabed & undergo metamorphosis (after finding a spot close to food that’s far from predators). • Larva takes on adult form in less than 30 mins (mini me) • Continues to eat algae/kelp to grow from juvenile to mature adult capable of reproduction (depending on species & nutrient availability) is ~ 3-5 yrs

  5. Sea Urchin Life cycle (Australia)

  6. Reproduction (captivity) • Spawning induced by injections of acetylcholine, potassium chloride or by electrical stimulation (placed in larvae tank to grow) • Cold to warm – induces spawning (spring) • Male & female have 5 gonadal “tongues” that contain nutritive cells with either eggs or sperm • Juveniles harvested from wild – achieve significantly increased roe (in aquaculture conditions) in just 12 weeks (not 20 mos in field conditions)

  7. Production methods used • Farming Strategies considered for grow-out include sea-based cage systems, sea ranching, and land-based tank systems. • Roe enhancement – juveniles caught from wild & allow growth for 12 weeks (in aquaculture conditions)

  8. Production method (cont.) • Stock enhancement – hatching out larvae in the hatchery and growing to small juveniles, then releasing in wild. • Placing small juveniles into cages along coastal waters (good water flow, no f.w. output, seaweed, and protection) to allow growth (500/cage)

  9. Feeds and feeding • Sea urchins eat seagrass, algae, kelp, and other greens • Brown algae accounts for 64% of the field diets and green algae, 24%.  • Oven dried powder pellets can be used - composed of carbohydrates and protein.

  10. Water Chemistry and Environmental Requirements. • Salt water ( can’t survive in freshwater) • pH 7.6 – 8.2 • 20-26 C

  11. Advantages andDisadvantages • Can adapt and survive in high density conditions ( 50-90 kg/m2) • Protection from predators via sharp spines • Slow moving • Reproduce in great numbers

  12. Sea Urchin Roe FOOOODS…..yum! http://www.youtube.com/watch?v=7ZF7F9Yv8k8&feature=related UNI !!!!!

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