A Department of Environment (DoE) project to see how far Nassau Groupers roam from the area where they spawn indicates that they do not travel far and do not travel over deep water.

At a recent presentation at the District Administration conference room, DoE Research Officer Bradley Johnson explained how a number of grouper from the Spawning Aggregation (SPAG) off the West End of Little Cayman had been tagged.

Each fish had been caught with circle hook and brought to the surface slowly. Scientists took blood and tissue samples and surgically implanted an acoustic tag. Fish were then released using a weighted barbless hook.

The entire process took about four to five minutes," said Mr Johnson. The fish had then been monitored using hydrophones in fifteen locations around Little Cayman and mobile hydrophones from boats.

The majority of tagged fish are still alive and, by tracking their movements over the course of the year, they have found that none of the fish appear to leave the Island and that fish are equally distributed around the Island.

Groupers live solitary lives on the reef three hundred and forty days of the year, but gather together en masse to spawn at SPAG sites around the full moon during January and February.

Monitoring of the tagged groupers showed that most fish attended the aggregation both months for 2005 and 2006.

The spawning site off the west point of Little Cayman is probably the last viable SPAG in the Cayman Islands, and this project indicates that the two to three thousand groupers that spawn there all come from that Island, and not from far away as some believe.

Other findings are that all, or nearly all, fish aggregate every year, and that older fish aggregate more often and stay longer. Whether there are any undiscovered aggregations around the Cayman Islands is yet to be determined, said Mr Bradley.

However, many traditional spawning sites around the Caribbean have been fished out and there are no viable SPAGs upstream of the Cayman Islands.

Describing the current status of Nassau Grouper SPAGs in the region, Mr Bradley said that just five of twenty-three remain in the Bahamas; in Cuba, three of twenty-two remain; in Belize, over half of thirteen SPAGs are considered extinct, and eleven have been shut down until further notice by the Government.

When the number of large spawners is reduced by fishing, reproductive behaviour is disrupted, which means not only fewer eggs are produced, but there are lower fertilization rates of those eggs produced, noted Mr Bradley.

The Little Cayman SPAG is protected because it is known that it functions, and is one of only a handful of aggregations with one thousand or more fish. No one has ever observed Nassau Grouper spawning outside an aggregation, and once gone, the fish may not return.

Bermuda banned catching Nassau Grouper thirty years ago but they still have not returned, observed Mr Bradley.

Groupers and Snappers are the most commercially and ecologically important reef fish and most are slow growing and long lived. They have late sexual maturity and form SPAGs at predictable places and times, which makes them very vulnerable to over-fishing.

Marine Conservation Laws regarding Nassau Grouper limit the size of fish caught to a twelve-inch minimum, which applies throughout Cayman waters year round.

However, no one may take Nassau Grouper from any of the Designated Grouper Spawning Areas, and no one may spearfish or set a fish-pot within a one-mile radius of any Designated Grouper Spawning Area from 1 November through 31 March.

In July, the DoE began repeating the tagging project on Cayman Brac, and five fish have so far been tagged and seven hydrophones placed around the Island.