Mozambique is becoming well-known among divers for its sun, sand and super-sized fish. Since 2005, we’ve identified over 600 individual whale sharks from the country. That’s about 18% of the known global population of the species! Most of these sharks are found along a small (6 km) strip of coast near our base in a village at Tofo Beach. These bus-sized giants visit this area year-round to engage in what appears to be their favourite pastime: munching plankton.
Project AWARE has been supporting whale shark research and conservation efforts in Mozambique since 2006. Our most recent project has harnessed ‘citizen scientists’ to help expand our research efforts. A burgeoning tourism industry has developed locally to help people get up close and personal with these enormous (but harmless) sharks, as they’re great fun to swim with. Photos from these divers are helping us to learn a lot more about these placid sharks.
Every single whale shark has a distinctive ‘fingerprint’ of white spots on each flank. Through collecting photos of the sharks, which any diver can take with a normal underwater camera, we can track the habits of each shark to learn about how and why so many are present in this particular site. We’ve been interested to discover that the majority of the sharks are moving through the area quite quickly, and we only see them for a few days. Others we see more regularly, but sometimes only once every few months or years.
We try to obtain as much information as we can on each shark. Males have paired reproductive organs called claspers on their undersides, so we can distinguish the boys from the girls, and we use a laser system to accurately measure their length. From this, we’ve been able to discover that most of the sharks visiting Mozambique (75%) are males, and almost all are juveniles of 4 to 9 m in length. This means that, while it’s obviously a very important ‘hotspot’, whale sharks don’t call Mozambique home. Even though we’re seeing literally hundreds of sharks, you could think of Tofo Beach as being like a petrol station on a whale shark highway, where these enormous fish stop for a time to refuel before their next trip.
We’re working hard to ensure that these sharks’ pit-stop is a safe one. We’ve seen quite a few sharks here that have been either hit by boat propellers or tangled in nets and, occasionally, they’re even killed along the Mozambican coast. This isn’t because the fishers particularly want to catch whale sharks – a big whale shark will usually tear a small gill-net apart, although it may severely damage itself in the process – but simply because more and more nets are being set along the coast.
So, what’s the answer? The key is to ensure that these fishers realise the value of these sharks. As marine tourism develops in the area, local communities have been helping to develop informal ‘safe zones’ for whale sharks and other marine life in exchange for increased participation in these businesses. This is also a positive feedback loop: more Mozambican divers means more ocean advocates, and more pressure on the government to institute protection for whale sharks.
Thanks to support from Project AWARE, we’re making excellent progress towards securing Mozambique as a safe haven for Earth’s largest fishes. It’s an amazing place, and a great case study of an effective marine conservation programme. This article is the introduction to a series of posts on this project; I hope you enjoy reading more about it over the next few weeks!