Happy Whale Shark Day!

Hi all!

It’s International Whale Shark Day! Which gives me a wonderful excuse to talk about whale sharks – though I'm rather good at slipping them into conversation most other days, too :P

I’ve been privileged to work with these gentle giants since 2005, when I saw my first whale shark off Mozambique. I’ve been a mostly full-time whale shark researcher ever since. Twenty years later, I’m still learning, and they’re still amazing.

International Whale Shark Day is a great excuse to talk about where whale sharks are ‘at’, conservation-wise.

First though, some context:

Modern-day whale sharks have been around for 20-something million years. Over that time, the oceans have expanded, contracted, warmed up, gone into ice ages, warmed up again, and whale sharks have had to contend with gigantic predatory sharks and even ‘killer sperm whales’.

Basically, they’re really, really good at avoiding drama and quietly getting on with their day, while munching as much plankton as inhumanly possible.

Sadly, what they **can’t** cope with is the rapid changes that humans have created. Contemporary whale sharks probably live to 80–100 years old, and don’t even become adults until they’re 25–40. Since 1950, well within the life of many whale sharks still swimming around today, the number of people on earth has tripled. Annual plastic production has gone up 200x, from 2 million tons per year to 400, and much of it ends up in the ocean. The world’s shipping fleet has also tripled, with 20x more cargo transported. Open-ocean fisheries barely existed in 1950. Now, there are hundreds of thousands of large fishing vessels in international waters.
Fortunately, conservation efforts have come a long way since I started working on the species in 2005. At that stage there were still large targeted fisheries for whale sharks in SE Asia, and evidence of major declines in whale shark populations was starting to pile up. These huge, placid sharks were in serious trouble.

A container vessel passes a whale shark feeding area off Mexico

We collated monitoring data for the current global assessment of whale shark conservation status, the IUCN Red List, in 2016. In 2021, we updated and added to this worldwide assessment through the IUCN Green Status process and, this year, I led the new Red List update (which will come out in a couple of months). We now have a reasonably good idea of the high-priority threats to the species.

Since the 1980s, over half of the world’s whale shark population has been killed by people. They are globally endangered, and may be critically endangered in some regions. Targeted fisheries, and probably shipping mortality too, have done most of the damage.

There has been a concerted effort to reduce the demand for shark fins and meat in China and Taiwan, and that has hugely benefitted whale sharks. China, India, the Philippines, and Taiwan, which previously had large whale shark fisheries, have now banned intentional catches of the species (I'm not saying it doesn’t happen, but it doesn’t happen nearly as much).

In the past couple of years we’ve also completed detailed analyses on global shipping and some other ‘cryptic’ threats. Deaths from shipping are very difficult (practically impossible) to track, as ships move fast and whale sharks generally sink when killed. To an extent, we can track regional risk by the number of sharks that bear impact scars – the Gulf of Mexico and Arabian / Persian Gulf are areas of particular concern.

The best way to protect these sharks is to seasonally re-route ships, or at least have them slow down when they’re near the (small, predictable) areas where whale sharks routinely feed on the surface in large numbers, as can be seen off areas off Mexico, Qatar, and the US.

A propeller-cut whale shark

Gillnet fisheries are another tricky one, as there’s little monitoring of this fleet, and it's huge. There are tens of thousands of vessels in the Indian Ocean alone, fishing with nets up to around 17 km in length (over 10 miles). These nets are, of course, *designed* to be hard for fish to see and avoid. This year we started the Oman Whale Shark Project specifically to investigate whale shark ecology and threats in the Arabian Sea, a global hotspot for tuna driftnet activity.
Plastic ingestion is also a threat to whale sharks and other filter-feeders – one that we’ve barely begun to understand. My major worry with plastic is that it's so difficult to quantify the danger. One whale shark, undergoing an extended recovery in a seapen after accidental capture in a gillnet off the Japan coast, eventually died from internal damage from a piece of plastic that had been swallowed over *six months* previously. We can't reliably track that kind of long-term harm in wild populations at this stage. We need to reduce the amount of plastic around whale sharks to improve their safety.
Unmanaged tourism is a very visible issue in some areas, and I’m not discounting it – it can put extra pressure on whale sharks at key feeding sites. I’m a firm believer in the conservation potential of ecotourism, but too much whale shark tourism falls well short of that standard. Please look for operators that support research and conservation efforts, and promote best-practice standards for swimming with whale sharks.

Mass tourism in the Maldives

These are a lot of challenges. Can we fix it? Yes we can!
Whale sharks are legally protected in *most* of the countries that are known to host important constellations (Madagascar and Oman, we’d love you to join the list!), and long-term protection efforts are starting to pay off. For instance, Western Australia – the spiritual home of whale shark research and ecotourism – has been seeing a fairly steady increase in whale shark sightings over the past decade.
Every year, more people become interested in whale shark research and conservation – and we’ve now got an amazing AI-assisted global whale shark ID database at sharkbook.ai, with over 15,000 individual whale sharks identified from more than 10,000 contributors all around the world. These community efforts are helping us monitor whale shark abundance, prioritise threats, and implement countermeasures on global, regional, and national levels.
Personally, it's always helpful to remind myself what can be achieved. I’ve just wrapped up an MMF dive liveaboard to the Galapagos Islands, where we watched thousands of critically endangered scalloped hammerhead sharks swimming through these protected waters. These sharks, one of the most valuable species in the global fin trade, are increasing in this marine reserve thanks to applied research, dedicated management, and a lot of conservation work.
Whale sharks can become a global success story too. With all of us working together, these gentle giants can bounce back. You can find out more about MMF’s whale shark work here: https://marinemegafauna.org/whale-sharks
Thanks for reading, and lets make the next year a fantastic one for the world’s greatest fish :)

We literally couldn’t do this research, conservation, and education work without our partners and donors – so a whale shark-sized thanks to all of you – and please do consider supporting us to protect these amazing sharks :)

Simon.