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Strombus gigas. The Queen Conch. Taxonomy. Kingdom: Animalia Phylum: Mollusca Class: Gastropoda Order: Mesogastropoda Family: Strombidae Genus: Strombus Species: gigas. A brief overview. Spiral shell with a smooth, pink inside ~ 5 pounds and ~ 1 foot long
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Strombusgigas The Queen Conch
Taxonomy • Kingdom: Animalia • Phylum: Mollusca • Class: Gastropoda • Order: Mesogastropoda • Family: Strombidae • Genus: Strombus • Species: gigas
A brief overview • Spiral shell with a smooth, pink inside • ~ 5 pounds and ~ 1 foot long • 20-30 years (can be 40) • Internal fertilization with egg casings • They live in warm, shallow marine water
Economic importance… • Jobs; income for the country (Caribbean); tourism; food; merchandise • Aquarium: ~$1.75-$2.75 each • Wild-harvested: ~$6.00-$15.00 /lb • U.S. greatest importer • Greatly overfished • U.S. banned commercial harvest
Economic importance… • Jobs; income for the country (Caribbean); tourism; food; merchandise • Aquarium: ~$1.75-$2.75 each • Wild-harvested: ~$6.00-$15.00 /lb • U.S. greatest importer • Greatly overfished • U.S. banned commercial harvest
Economic importance… • Jobs; income for the country (Caribbean); tourism; food; merchandise • Aquarium: ~$1.75-$2.75 each • Wild-harvested: ~$6.00-$15.00 /lb • U.S. greatest importer • Greatly overfished • U.S. banned commercial harvest
Reproduction in captivity • Queen Conch egg cases are either gathered from the wild, or from an “egg farm” • Mesh circle in warm shallow waters, slow current; optimal breeding grounds • Farms are stocked with an equal ratio of male and female with a density of 1 conch per 100 square ft • There is proof that S. gigas can reproduce in a recirculating system, though not as well
Pre-adult stage • Eggs hatch after ~5 days • Live as planktonic larvae for ~ 18-40 days
Hatchery and Metamorphosis Metamorphosis tray with screens Larval tank: either static or a flow-through Inducers added; washed off and the conch are left to grow until they reach and avg. size of .12 - .14 inches Kept with food until they’re ready for metamorphosis
Nursery Can be recirculating or flow-through
Feeds and feeding • Larvae: • Phytoplanton and Microalgae • Nursery: • Fed once a day with either a gel-based diet or a commercial conch chow • Ground Koi or Catfish pellets, dried Ulva sp. seaweed • Commercial feed has an FCR of 1.5:1 (dry weight of feed to total wet weight of conch) • Grow-out: • Natural food supply maybe supplemented with feed
Environmentalrequirements • General: • Ocean conditions (Salinity = ~35 ppt, Temp = ~30°C ) • Shallow marine water • Veliger Larvae: • Culture: 28° C (or 24-32°C) and 36 ppt (or 26-40 ppt) • Inducement: 28-30° C with Laurenciapoitei(a red macroalgae) extract and small amounts of hydrogen peroxide • Nursery: • 27-29° C • Shaded areas, with a sand layer and sea water; water speed depends on multiple factors • Grow-out: • Sandy-bottomed area, medium amount of plants, strong tidal currents to flush the area
Advantages Disadvantages • Smaller conch are ready for market sooner (6-12 months) • No high importing costs (seaside hatchery) • Replenish wild population • Cheaper market prices • Grow out is low maintenance • They have a really long maturing time (overfishing) • There are a lot of steps involved • It needs large amounts of space • The grown conch are smaller than the wild ones
Fun facts • Because they can’t really change direction well, the grow-out pens have to be circular, otherwise all the conch would get stuck in the corners • When their blood has oxygen in it, it looks blue due to the hemocyanin (has copper, not iron)