BBC Oceans: Indian Ocean - coastal waters

Oceans cover two-thirds of our planet, they hold clues to the mysteries of our past, and are vital for our future survival. That is the message this BBC nature documentary has been trying to get across. In this second installment about the Indian Ocean the focus is on the Spice Islands off Tanzania, on the edge of two continents, where the full force of the Indian Ocean collides with the African coast. These waters are a nursery supporting an enormous diversity of marine life. But the ocean’s currents can also cause unpredictably heavy weather (rain, storm, monsoons, cyclones), that can trigger floods, droughts and famine. The Spice Islands, moreover, are an intense meeting point of man and sea, particularly vulnerable to human impact. Starting at the north of the archipelago, Tooni Mahto and Paul Rose dive inside a submerged facture in the solid rock on the edge of Pemba Island, a fissure between the two continents. They find a recess teeming with life, where the inhabitants have adapted to living in the shadows. One example is green tree coral which does not contain algae, but feeds by filtering the food that the currents sweep into the passageway. At night, Tooni and Philippe Cousteau Jr assess the health of the coral reefs and find a wide variety of species, including large table corals, staghorn and pineapple corals. Naturally, environmental conservationist Philippe is visibly excited about the reef’s vibrancy. Off Zanzibar, the team takes coral core samples to create a data record of weather patterns that could help scientist predicting natural disasters.

Tooni and Paul then show us the marvelous land crabs, that are halfway between land and sea creatures with lungs and gills, lay their larvae in the water but live their adult life on land. Then Philippe and Tooni visit the mangrove lagoons around Mafia Island in search for the enigmatic sea horse in the lively waters teeming with juvenile scorpion fish, yellow box fish, tiny squid, and hermit crab. Sea horses have been heavily exported from Tanzania for the traditional eastern medicine market. They actually find the largest recorded specimen of its kind. On the west coast of the island, maritime archaeologist Lucy Blue dives with Paul to study the remains of the village of Ras Kisimani washed into the sea by a cyclone in 1872. Not only is the seaboard littered with nineteenth century local pottery, but she also discovers fifteenth-century Persian ware, as well as fourteenth century East Asian ceramics. The site was thus once a trading hub between Africa, Arabia and Asia. Finally, Philippe has the chance of a lifetime to swim with a group of whale sharks, the world’s largest fish. Not a bad episode, but not exceptional either.