Strombus gigas

The Queen Conch

Taxonomy Kingdom: Animalia

Phylum: MolluscaClass: GastropodaOrder:

Mesogastropoda Family: StrombidaeGenus: StrombusSpecies: gigas

Spiral shell with a smooth, pink inside~ 5 pounds and ~ 1 foot long20-30 years (can be 40)Internal fertilization with egg casingsThey live in warm, shallow marine water

A brief overview

Jobs; income for the country (Caribbean); tourism; food; merchandise

Economic importance…

Aquarium: ~$1.75-$2.75 each

Wild-harvested: ~$6.00-$15.00 /lb

U.S. greatest importer

Greatly overfishedU.S. banned

commercial harvest

Jobs; income for the country (Caribbean); tourism; food; merchandise

Economic importance…

Aquarium: ~$1.75-$2.75 each

Wild-harvested: ~$6.00-$15.00 /lb

U.S. greatest importer

Greatly overfishedU.S. banned

commercial harvest

Jobs; income for the country (Caribbean); tourism; food; merchandise

Economic importance…

Aquarium: ~$1.75-$2.75 each

Wild-harvested: ~$6.00-$15.00 /lb

U.S. greatest importer

Greatly overfishedU.S. banned

commercial harvest

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 groundsFarms 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

Reproduction in captivity

Pre-adult stage

Eggs hatch after ~5 days

Live as planktonic larvae for ~ 18-40 days

Hatchery and MetamorphosisLarval tank: either static or a flow-through

Kept with food until they’re ready for metamorphosis

Inducers added; washed off and the conch are left to grow until they reach and avg. size of .12 - .14 inches

Metamorphosis tray with screens

Nursery

Can be recirculating or flow-through

Grow-out

Larvae:Phytoplanton and Microalgae

Nursery:Fed once a day with either a gel-based diet or a

commercial conch chowGround Koi or Catfish pellets, dried Ulva sp.

seaweedCommercial 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

Feeds and feeding

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 Laurencia poitei (a red

macroalgae) extract and small amounts of hydrogen peroxide

Nursery:27-29° CShaded areas, with a sand layer and sea water; water

speed depends on multiple factorsGrow-out:

Sandy-bottomed area, medium amount of plants, strong tidal currents to flush the area

Environmental requirements

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

Advantages Disadvantages

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

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)

Fun facts