Conch Farming

Conch Farming

Conch Farming is a marine aquacultural business focused on the cultivation of the Queen Conch (Strombus gigas).

The Queen Conch

The queen conch is a large marine mollusk that can be found throughout the Caribbean Sea and is also one of the most valuable fishery resources in the locations where it is found. (Oceana, 2018) The Queen Conch can live up to 40 years and its shell can reach lengths up to 12 inches over the lifespan. The queen conch fisheries expand across the entire Caribbean with major industrial fisheries in Jamaica, The Bahamas, Turks and Caicos, Cuba, Honduras, and Belize. (Appeldoorn et al. 2011) The export value of the queen conch is estimated at US$89,915,000 in 2000. (FOA 2002) The queen conch economic value is in its meat that is consumed as a delicacy and its shell and pearl jewelry value. (USFWS, 2018) Due to overfishing and uncontrolled harvesting, the conch number has severely declined and it was subsequently listed as an endangered species by CITES in 1992. (Cites 2008)

History of conch farming

Conch farming originated in 1984 on the Islands of Turks and Caicos. Since then other places like Florida Straits Conch Company that started in 1999 and also in Mérida Mexico they cultivate conch for research purposes. (FAO 2004)

Problems in the Industry

Even though the culture has been around for a few decades, conch aquaculture has a lot of room for improvement. The improvement of husbandry techniques for grow-out of juveniles in particular is needed. Factors like stocking densities, substrate and nutritional requirements are not well known.

Diet

The natural diet of queen conch is a mixture of live algae, diatoms and detritus found on the bottom substrate. The main algal species used to culture the juvenile queen conch are Spirulina platensis, Spyridia filamentosa, Ceramium fastigiatum, Dictyota cervicornis, and Enteromorpha prolifera. They can also be fed an artificial diet but both artificial and live diets seem to be less efficient in cultured conch than in wild juvenile queen conch. (Garr, 2011) The growth rate of the juvenile conch fed the standard diet at the Aquaculture Division of the Harbor Branch Oceanographic Institution hatcheries was 80µM per day. The standard diet was a mixture of 36 % catfish feed, 16% of Ulva sp., 5% alginate and 43 % seawater. This mixture of the artificial diet with the microalgae is crucial to the survival rate of the juvenile conch. Another issue in the feed is the amount of protein in the diet, because the conch only eats to meet its energy requirements maximizing the protein to increase growth is complex. The protein is also the most expensive component of aquaculture feed therefore an accurate assessment of protein utilization must be met in order to reduce the cost of manufacturing feeds. (Garr, 2011)

Stocking density

Another issue with the rearing of juvenile conch is stocking density. Studies have found that juvenile conch that are grown in more 20 to 50 conchs per m2 exhibit a very slow growth rate compared to individuals grown at a lower density. (Creswell 2005)

Farm Closure

These major issues coupled with lack of government funding was the reason why the largest queen conch farm in the world, the Turks and Caicos conch farm was shut down. The farm offered an educational tour of the site giving visitors a close up look at the development of the queen conch. All of the micro algae that was fed to the mollusks were cultivated on site. The adult queen conchs were reared in sea cages while the juvenile conch were reared in flow-through tank systems. While the company was open it sustained 1.6 million a year in exports of queen conch from the farm. That’s about 49% of the islands export value in fisheries. Even though from a biological point of view the company was being managed well and appeared to be in a good state the lack of funding for this conch farm was detrimental to the site. Also lack of research on the topic of feed nutrition, shell morphology and stock density in farming conch is a major issue. (Webref. 2019)

References

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