In November and December 2015, I had the good fortune to be able to spend two weeks in southern Mozambique at the Ponta do Ouro Partial Marine Reserve. I was sampling with Rhett Bennett and John Filmalter, post-docs at the South African Institute for Aquatic Biodiversity, and Ryan and Clare Daly from the Save our Seas Foundation in the Seychelles.
One objective of this trip was to tag individuals of the Giant Kingfish (Caranx ignobilis, aka Giant Trevally, or “GT”) as they came together to form a massive spawning aggregation off the coast. We successfully inserted acoustic tags into 14 individuals, and will be following their movement patterns in northern South Africa and southern Mozambique over the next few years.
The size of this spawning aggregation is incomparable to any other gathering of GTs recorded throughout the rest of the world! My co-researchers estimate there are approximately 4,000 of these fish; so many that they turn the water green at the surface!
Another accomplishment of the trip was collecting fin clip samples and muscle tissue for genetic and stable isotope analyses, respectively. I am busy in the lab analyzing these samples, which will tell us about the genetic diversity within individuals at the spawning aggregation, and where they sit in the trophic food web. This information, in combination with the tagging data, will paint a clearer picture of the ecology, evolution and behavior of this fascinating species!
Ponta do Ouro is a beautiful part of the world. It’s reassuring to learn that Mozambique, ravaged by years of civil war, is promoting the sustainability of its oceans by designating these biologically significant regions as reserves.