Little Compass RoseCaribbean Compass  November 1999
Fish Kill
Theories Abound,
but Still No Answers
It started during the recent rainy season. Nobody knew what was causing it. Hundreds of dead fish were appearing, floating in the sea or washed up on the beaches along certain shorelines in the Windward Islands.

Reports indicate that the phenomenon may have begun in Guyana in July. The first report in the islands came from Peruvian Vale on the eastern coast of St. Vincent, where fishermen said they started noticing quantities of dead fish on 28 August. Similar fish kills were subsequently reported in Grenada, Barbados, Bequia and Tobago. All reports came from the northeastern, eastern or southeastern coasts of the islands. Grenadian zoologist Ros Dopwell tells Compass that there have been no regional fish kills of this magnitude in living memory, although there have been smaller isolated incidents.

The first kills occurred after heavy seasonal rains. The initial victims were herbivorous reef fish living at depths of 10 to 20 meters. But soon other species, including grouper and snapper, became affected, indicating a movement of the unknown killer agent into deeper waters.

On 3 September, the Fisheries Division of St. Vincent & the Grenadines issued warnings to the public to desist from selling or consuming fish found in specified areas, and a scientific investigation got underway. The other affected countries began their own investigations, as did regional agencies concerned with fisheries, health and the environment.

The reported findings were often contradictory, and the public became increasingly confused and alarmed.

An early report from Grenada indicated that "the dumping of hazardous chemicals and toxic waste from a cruise line is responsible." That nation's Prime Minister, Dr. Keith Mitchell, immediately issued a counterstatement: "Let us not speculate and attach blame without proof."

St. Vincent's Minister of Agriculture, Jeremiah Scott, quoted in local newspapers, said that water samples "suggest that some sort of toxic chemical may have been present." A fisheries official in Barbados was then quoted on a Caribbean Broadcasting Union (CBU) television report as saying that "conclusive evidence [is that the cause of the fish kill] is likely [to be] biological rather than chemical."

Dr. Wayne Hunte, a professor of marine biology at the Bellairs Research Institute in Barbados, said on that island's CBC-TV newsmagazine that the most likely conclusion was that the fish died from oxygen deprivation caused by an organism carried to the region by the Guyana Current. Dr. Geoff Wigham, of the marine biology program at St. George's University in Grenada, agreed that nutrient-rich waters from the Orinoco River in northern Venezuela may have played a part, but stated that it was toxins produced by a resulting algae bloom (a proliferation of microscopic marine organisms), rather than simple oxygen deprivation, that killed the fish. Word then came from the Institute of Marine Affairs in Trinidad that it was possible that an algae bloom was not the culprit, as conditions for such an event had not been favorable.

Meanwhile, the dragnet of speculation had rounded up yet more theories for the cause of the fish kill but underwater seismic activity, the purported sinking of a nuclear submarine and "it's the end of the world" were generally discounted.

Then another suspect was added to the plot. A Scottish fish pathologist, Dr. Hugh Ferguson, summoned from the University of Sterling to assist in Barbados's investigation, said he blamed the fish kill on a bacterial infection: "Microscopic examination of tissue samples revealed lesions consistent with a bacterial disease. Culture from tissues of these fish by the Veterinary Services Laboratory indicated that the organism was streptococcus iniae." This development triggered more alarm Barbados's Minister of Heath Senator Philip Goddard warned the public in an article in The Nation newspaper that streptococcus iniae could be transmitted to humans, and cautioned anyone handling dead fish to wear protective gear including "boots, goggles, respirators and gloves."

But a fisheries expert in Grenada quickly expressed reservations about the "strep" theory. According to Barbadian veterinarian Dr. Stephen St. John, this would be the first time streptococcus iniae occurred in saltwater fish species rather than in fresh water, where it is not uncommon. St. Vincent's Chief Fisheries Officer Kerwin Morris had previously noted that "One of the first observations of the fish kills [was that] not a single freshwater species [was affected]."

Because the cause of the fish kill is still being debated, health-risk warnings have also been contradictory.

If, as Dr. Hunte surmised, the fish kill victims had died of oxygen deprivation, there would be no danger in consuming other fish which may have eaten the dead fish. Indeed, in early October, Barbados's Minister of Agriculture Anthony Wood said "fish other than reef fish pose no threat at the moment." However, if the cause of death was toxins from an algae bloom, American scientist Donald Anderson warned in a 1998 Seattle Times article that "some of the toxins that originate in algae concentrate as they move up the food chain to the largest fish" and can affect humans. Other scientific sources add that shellfish, including lobster, conch and whelks, should also be avoided because toxins accumulate in their tissues and could be passed on.

The Vincentian newspaper reported that Grenada's Dr. Wigham said that "even though the dead fish may look and smell bad, they can be eaten by humans if the head, gills, lungs and liver are removed." This statement was swiftly condemned by other experts as "premature and unfortunate".

A CBU television broadcast more recently warned that if a fish has died from streptococcus iniae infection, it is "totally unfit for human consumption," although the Barbados Minister of Health noted that fish caught live could be eaten, but should be thoroughly cooked, since the streptococcus bacteria could be transmitted to humans.

Not knowing what advice to take or what the real risks might be, many people have given up eating fish entirely. Others never stopped, and interestingly, there have been no confirmed reports of any illness in humans occurring as a direct result of the fish kill, no matter what types of fish have been eaten. Some experts, however, warn of possible health problems, such as liver damage, surfacing in the future if certain toxins were present in the eaten fish.

Both the confusion and the investigations continue.

An October report made by the Caribbean Fisheries Unit/CARICOM Fisheries Resource and Management Programme (CFU/CFRAMP) stated that "although most countries affected have done some investigation, at this stage we are still not sure what is causing the fish kill. The only thing that is certain is that the marine environment is under stress and several species of fishes are not able to survive in the waters."

At a regional workshop held in Barbados on 16 October, fisheries experts from the affected countries met to share their preliminary findings. Also present were representatives of the Caribbean Epidemiology Centre, The Pan-American Health Organization, the University of the West Indies, Caribbean Planning for Adaptation to Global Climate Change, the Institute of Marine Affairs, the Caribbean Disaster Emergency Response Agency, the Food and Agricultural Organization of the United Nations and the Organization of Eastern Caribbean States Natural Resources Management Unit. On the agenda for the one-day meeting were possible causes of the fish kill, and its socio-economic and public-health impacts. Results of this meeting were not yet available as this issue of Compass went to press, but according to the Caribbean News Agency a report was expected to be made at a meeting of the CARICOM heads of government in Trinidad on 26-27 October.

It is already apparent that the fish kills have seriously depleted the region's main source of non-imported protein, and may cost many people their livelihoods. The St. Vincent Fisheries Division reports that up to 60 percent of that nation's fishermen are currently not going out, and fish vendors have seen a 75 percent drop in sales. Exports of fish to Martinique have been halted. It is estimated that if current trends continue, St. Vincent's fishing industry will lose some EC$507,000 (nearly US$190,000) per month. Unofficial estimates in Barbados place a one-month loss to fishermen, vendors and restaurants at between Bds$500,000 and Bds$600,000 (US$250,000 to US$300,000). The other affected islands face similar losses.

Officials are concerned about other possible impacts of the fish kills. Will crime increase as hundreds find themselves without work? Will tourism suffer? Will precious foreign exchange be spent on American chicken to feed the populace, or will those local seafood resources presumed to be unaffected be overharvested?
The good news is that reports of dead fish are becoming less frequent.

But the question remains why did they die?


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