By the BBC's
Joseph Warungu

They call Zanzibar the spice island on the Indian ocean. But spices are not only to be found on the farms - the island's politics have been hot and spicy ever since the bloody revolution that overthrew the Sultan in January 1964.

This election year is no different. The ruling CCM party has engaged the opposition CUF in a bruising struggle for power in the run-up to Sunday's elections. CCM remembers only too well the scenario in the 1995 election when it narrowly scraped through to State House, but lost all the parliamentary seats on the Zanzibar's sister island, Pemba. This time it wants to make sure it leaves its mark on Pemba politics.

The Zanzibar archipelago is one the largest producers of cloves in the world - the bulk of which are grown on Pemba. At the height of Zanzibar prosperity some few years back, the country produced 18,000 tonnes of cloves a year. Today on a good year, Zanzibar only manages 8,000 tonnes.

Agriculture therefore ranks alongside trade, fishing and the general state of the economy among the key issues in this election.

Both the opposition and the ruling party similarly want to capitalise on Zanzibar's tourism potential, which is yet to be exploited fully. The Zanzibar isles - particularly Pemba - are blessed with beautiful, sleepy and unspoilt beaches and coastline, which are beginning to attract classy holiday makers in search of deep-sea diving and fishing.

There's so much at stake in Zanzibar - with some worrying about the future of the union arrangement with mainland Tanzania - that the central government has despatched security forces from the mainland to reinforce security on the island.

The likelihood of trouble in this week's polls has kept away some tourists who are attracted by the oriental-style architecture. But this is likely to be short-lived, as Zanzibar is one Indian ocean island that many find hard to resist.