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The Future of Conch

Saving TCI’s iconic fishery.

By Kathleen Wood ~ Photos By Marta Morton

Imagine the Turks & Caicos Islands without steamed conch, stewed conch, grilled conch, cracked conch, conch salad, conch fritters, conch and rice or conch chowder. The queen conch (Strombus gigas) has been the mainstay of the TCI diet since Lucayan Indians first inhabited these shores more than 1,000 years ago. Since the latter part of the 19th century, when robust trade with Haiti and the Dominican Republic began, conch has also been one of the leading contributors to TCI’s economy. Conch is one of the country’s few export commodities, and it is a critical component of local watersports, native crafts and the restaurant industry, contributing millions of dollars annually to people’s livelihoods. The conch’s cultural and economic significance is exemplified in the pink-lined, spiral shell gracing the TCI flag. Conch is TCI’s iconic fisheries species. Envisioning TCI without conch seems unimaginable, but that is what may happen if steps aren’t taken soon to ensure its survival.

For most of its history, the Turks & Caicos has enjoyed one of the most robust conch fisheries in the Caribbean. Most years, the country was the leading supplier of conch to the United States, but everything started to change in 2009, when the quantity of conch harvested in TCI plummeted by more than 50% from historic levels. Although the situation has improved slightly since then, catch continues to hover persistently around 50% of previous years’ levels. Furthermore, the conch that are being landed are becoming smaller and smaller with successive years, indicating that adult conch are becoming more scarce.

The conch's significance to TCI is huge.

The conch’s significance to TCI is huge.

Initially, the decline in conch stocks was thought to be a result of the double strike of hurricanes Ike and Hannah in 2008. These devastating storms caused hundreds of millions of dollars in damages to property in TCI, particularly around Grand Turk, Salt Cay and South Caicos. TCI has had severe hurricanes in the past, however, and conch stock never collapsed previously as a consequence. The hurricanes alone cannot account for the problem. If that were the case, stocks should have rebounded by now, as young produced by surviving conch would have repopulated the fishery within four to five years after the passing of the storms. Seven years have now passed since the initial collapse, and we must look to other causes and develop innovative solutions to ensure that TCI’s iconic conch do not disappear into the archives of history.

Legal protection and existing conservation

To save TCI’s conch fishery, it is logical to assume that legislative changes will need to be made. The laws already in place have simply not been effective in sustainably managing the fishery. The Fisheries Protection Ordinance regulates conch fishing in TCI. Currently, the primary laws include the following:

• A closed season between July 15 and October 15 each year, when conch meat cannot be exported, but can still be fished and consumed locally.

• A ban on fishing conch with a shell length smaller than seven inches or a total meat weight of less than eight ounces, once the digestive gland has been removed.

• A ban on artificial breathing devices (scuba and hookah) to harvest conch or any other seafood product, protecting deep water stocks.

• A proposal is also in place to implement a restriction on the weight of fileted or cleaned conch, but this has not yet been ratified into law.

Internationally, conch is considered an endangered species under the Convention on Trade in Endangered Species (CITES). CITES requires that the fishing and international sale of conch does not cause any detriment to the species. In other words, in order for TCI to be allowed to export conch to CITES member foreign markets, such as the United States (TCI’s largest and most significant export market), TCI must demonstrate that the fishery is sustainably managed. In order to fulfil this obligation, TCI has historically established an export quota, in addition to the above regulations. The export quota is based on figures derived for the maximum quantity of conch that can be harvested sustainably each year [known as maximum sustained yield (MSY)].

The complicated life history of conch

This peek into the conch's shell reveals the live animal.

This peek into the conch’s shell reveals the live animal.

The above precautions are dated and have not gone far enough to protect TCI’s conch. Current fisheries science recognizes that an ecosystem approach to management (e.g. taking into consideration the animal’s habitat requirements, life history and other “big picture” realities) results in significantly improved sustainability outcomes. Such an approach would certainly help TCI’s conch, which have complicated life histories and special habitat requirements.

They are grazing animals, dining on the algae and other microflora and fauna that grow on seagrasses and on shallow sand and rocky bottom. Because the conch’s habitat is dependent on plants, which require light for photosynthesis, conch are generally restricted to marine habitats of less than 30 meters in depth, where sufficient sunlight can penetrate the water column. The destruction of seagrass beds and other shallow marine habitats is therefore highly detrimental to conch. One of the most important ways to help the conch fishery is to ensure that critical conch habitats are protected, particularly those areas that are important for spawning and those that provide shelter and foraging for vulnerable juveniles.

TCI’s local lore suggests that historically the conch fishery has been protected from overharvesting due to the presence of deep water stocks, which are too deep to reach by freediving. Regrettably, such lore contradicts the latest scientific observations, which indicate that conch do not inhabit deep water in large concentrations due to an unavailability of food. Furthermore, genetic testing in Florida and the Bahamas has shown that conch larvae do not travel over large distances, meaning that conch populations are highly localized, and once depleted, are unlikely to be replenished via conch from other areas.

We have already observed this phenomenon in TCI. Fishers once fished for conch in shallow water, using a looking glass and a hook. Shallow conch were eventually fished out, forcing fishers into deeper areas. Fishers then moved from using the looking glass to freediving with a mask and fins. Conch have never returned to shallow areas, suitable for looking glass and hook fishing, in large enough quantities to make them commercially viable. Much of the conch accessible through freediving have now also been fished out, and some fishers are now asking to be allowed to use scuba gear to be able to access conch at depths greater than 20 meters.

Individual conch reach their maximum size before sexual maturity, which usually takes place between four and five years of age. Thereafter, growth is limited to an increase in shell thickness (A. Stoner, Mueller, Brown-Peterson, Davis, & Booker, 2012). Depending on environmental variables, the size of queen conch at maturity varies widely; therefore, size is not a good indicator of maturity. Because of this, TCI’s size restrictions are relatively meaningless from a management point of view. In order to ensure that legislation matches the conch’s natural history, a shell-thickness regulation should also be in place, ensuring that conch have the opportunity to reach sexual maturity and spawn before being harvested. Research has determined that the shell thickness at sexual maturity is at least 15 millimetres for females, and 10 millimetres for males (Mueller & Stoner, 2013; A. Stoner et al., 2012).

Conch also reproduce sexually with internal fertilization (just like we do). Unlike us, however, conch are extremely slow moving, so large densities of animals are required in order for successful reproduction to take place. Otherwise, they simply can’t find each other in order to mate. A number of studies in Key West and the Bahamas suggest that ideally, 100 adults per hectare may be necessary to ensure successful reproduction (Glazer, 2001; Allan W Stoner, Davis, & Booker, 2012; A. W. Stoner & Ray, 2000). This fact may explain why when conch stocks have collapsed, they have been slow to come back, if they ever do. Florida’s conch fishery collapsed in 1975, due to overfishing, and it has still not recovered.

Protecting dense populations of mature adult conch is therefore essential to ensuring that the fishery remains viable. Historically, fisherfolk have targeted spawning aggregations (areas where members of the same species gather in large numbers for the purposes of reproduction) for harvest because large quantities of conch can be easily harvested at the same time at such locations. Unfortunately, this practice is particularly detrimental because it removes the animals from the ecosystem at precisely the time they are reproducing and restocking the population. After successive years of such practices, spawning aggregations become fished out and are then no longer viable for the replenishment of the fishery.

Conch begin to spawn in early spring, when water temperatures start to get warm. Most spawning takes place between March and August, similarly to the Caribbean spiny lobster (Panulirus argus), TCI’s other main fishery. Unfortunately, this means that any meaningful closed season for conch (or a time of the year when fishing is not allowed in order to allow a species adequate time for reproduction) would be approximately at the same time as TCI’s closed season for lobster. Closing the two leading fisheries in TCI at the same time would undoubtedly cause hardship for fishers, unless an alternative, viable fishery, based on another species, can be developed. Deepwater and pelagic fish stocks are good candidates for such development.

Towards a sustainable future

Time is of the essence to restore and sustainably manage TCI’s conch fishery. First, an accurate estimate of existing populations must be determined. In 2013, the Department of Environment and Maritime Affairs [(DEMA) now the Department of Environment and Coastal Resources (DECR)] began conducting a population survey of queen conch. Preliminary results indicated that overall densities of adult conch in TCI may be as low as 14 per hectare, far below densities required for successful reproduction. If ongoing study confirms this, then a complete closure of the fishery will be required for a period of four to five years. Such a closure will allow existing juvenile conch to reach sexual maturity, increasing the densities of adult conch required for reproduction at spawning sites. The fishery should not be reopened until such densities are achieved.

Once appropriate densities have been restored, shell length and weight regulations should be replaced with regulations stipulating a minimum shell thickness of 15 millimetres. To enforce this, conch will need to be landed whole and in the shell. Such a regulation will also reduce the number of conch fished, as fishers are limited by the amount of weight they can carry on their boats. A closed season that matches the conchs’ spawning cycle, from March through August, should also be instituted. This season should be completely closed, with bans both on export and local consumption. Finally, the fishery cannot survive if the conch’s habitats are degraded or lost; therefore, all spawning and juvenile habitats should be established as protected areas and protected from fishing pressure and environmental degradation. Implementing the measures would successfully maintain the amount of conch that can be sustainably harvested indefinitely. Such measures have been found to be more effective in managing fisheries than traditional MSY and quota strategies, but they must be implemented before conch densities become too low to allow for recovery.

TCI’s historic conch fishery is now at a crossroads. Humans have the tools to restore the fishery and ensure its longevity and abundance into the future. Let’s hope that our children learn about TCI setting a positive example for the entire Caribbean region.

Sources cited

Glazer, R. (2001). Queen Conch Stock restoration. Florida Marine Research Institute South Florida Regional Laboratory. Marathon, FL. 7p.

Mueller, K. W., & Stoner, A. W. (2013). Proxy Measures for Queen Conch (Strombus gigas linné, 1758) Age and Maturity: Relationships Between Shell Lip Thickness and Operculum Dimensions. Journal of Shellfish Research, 32(3), 739-744. doi:10.2983/035.032.0316

Stoner, A., Mueller, K., Brown-Peterson, N., Davis, M., & Booker, C. (2012). Maturation and age in queen conch (Strombus gigas): Urgent need for changes in harvest criteria. Fisheries Research, 131-133, 76-84.

Stoner, A. W., Davis, M. H., & Booker, C. J. (2012). Negative Consequences of Allee Effect are Compounded by Fishing Pressure: Comparison of Queen Conch Reproduction in Fishing Grounds and a Marine Protected Area. Bulletin of Marine Science, 88(1), 89-104.

Stoner, A. W., & Ray, M. (2000). Evidence for Allee effects in an over-harvested marine gastropod; density-dependent mating and egg production. Marine Ecology Progress Series, 202, 297-302.



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Marta Morton, owner of Harbour Club Villas, shot this photo on the magical island of Salt Cay. The foreground is filled with the endemic National Flower Turks & Caicos Heather in full bloom. St. John's Anglican Church, built in the early 1800s, is in the background. To see more of her work, visit www.myturksandcaicosblog.com

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