For the month of April 2014, National Geographic Pristine Seas expedition leader Paul Rose will lead a group of key scientists and filmmakers, together with National Geographic Emerging Explorer Andrea Marshall and the Marine Megafauna Foundation, to explore, survey, and record what they expect to be some of the healthiest reefs in East Africa, home to ocean giants like manta rays, dugongs, and more.
We’ve had some “diving on the wild side” to make the best use of these very challenging conditions: This includes launching our boats into 8 feet of dumping surf and a high speed long-shore current, thumping our way 9 miles out to sea where the waves are 12 feet with the howling wind blowing the tops off them and with an underlying huge swell that has traveled across the Indian Ocean to test us. Even at 112 feet deep that powerful ocean surge is pushing us around and sending heavy storms of bottom sediment over us in an underwater version of a desert sandstorm reducing our visibility to near zero. It’s uncomfortable, adventurous hard work and at times like these I like to take a step back and reflect on our progress, so I asked marine scientist Dr. Phanor Montoya-Maya for a science update. Here’s his report.
By Phanor Montoya-Maya
One of the goals of this expedition is to document a gradient in reef life, one that only the Inhambane province in Mozambique offers. The first sites surveyed by the science team have confirmed that we are on the right track to achieve our scientific goal.
The expedition will survey a 350km-long stretch of coast, from Zavora Point in the south to the Bazaruto Archipelago in the north. We expect to find a gradient in reef biodiversity as we move north: from the subtropical, cold water, soft-coral dominated coral communities growing over fossilized sand dunes to the tropical, warm water, hard-coral dominated coral reef formations that have been known as the rainforest of the sea.
The expedition has started in the south. Hence, our first dives have been subtropical in nature. In other words cold, deep and in very rough sea conditions. The southern African coast has proven not to be for the fainthearted. Despite strong winds, up to 12 foot swells and limited visibility, the scientific team has managed to conduct comprehensive surveys of the reefs. The preliminary analysis of the data collected is motivating.
Lots of fishes, corals, macroalgae and marine invertebrates in general have been documented. According to Dr. Alan Friedlander, our fish specialist, these subtropical reefs appear to be very diverse, with many fish species that do not appear listed for this area. Although sharks were seen, other top predators such as potato bass groupers were very large and common.
As for corals, the reefs are clearly subtropical in that they are dominated by dimorphic, leather and thistle soft-corals with very few hard corals here and there. The dominance of flat and encrusting rather than massive and branching corals illustrates the marginal conditions for coral growth that are found in this area.
The surveys also confirmed the presence of a deep bed of the spined kelp in this subtropical region; kelp is a cold water macroalgae that is found predominantly in cold water environments, so its presence at this latitude is very unusual. Dr. Enrique “Kike” Ballesteros, our algae specialist, suggests this kelp forest could be a relic population that has survived the test of time or the result of opportunistic recruitment favored by particular oceanographic conditions, like the occurrence of upwelling that results in more temperate-like conditions for kelp.
All in all, it seems we can tick-off the subtropical limit in our biodiversity gradient. Now, as we move north, we expect to find more and more tropical fauna. That means more corals, more fish, and fewer algae! Exciting times ahead await our science team. Let’s hope the weather and sea play their part and they get more pleasant diving conditions.
Phanor’s hopes look to be coming true as this day of inshore work has been magical: We’ve been sailing with local fishermen, diving the sea grass beds, filming the iconic pink flamingos and for a few fleeting moments we even had a dugong mother and calf for company. Too short of a moment to film or dive with them – but it was the perfect sign of great things to come.
The Pristine Seas Mozambique expedition is sponsored by Blancpain and Davidoff Cool Water.