Randi Rotjan: Saudia Arabia Expedition
As a coral reef scientist at the New England Aquarium, I sometimes walk past the reef tanks in our exhibit for inspiration, or to reacquaint myself with the public opinion on coral reefs. Without fail, within less than 2 minutes of reef tank observations, a very smart Aquarium visitor notices "Nemo" on exhibit in the main building. Pixar's Finding Nemo has captivated audiences across age and culture, and clownfish have also captured the attention of Dr. Michael Berumen (KAUST) and his team. There are multiple scientific objectives on this boat; examining clownfish population genetics is one of them.
Clownfish (Amphiprion bicinctus) with a host Heteractis spp. anemone in the Red Sea.
Clownfish have a symbiotic relationship with Heteractis anemones. Each clownfish has a resident anemone. In this mutualism, clownfish have a protected shelter (the stinging anemone keeps predators away), and anemones also receive protection (clownfish are aggressive defenders of their anemone dwelling). In the Red Sea, there is only one species of clownfish: Amphiprion bicinctus. Given the relatively small size of the Red Sea (approximately the size of California), and the single species of clownfish, Michael and his team have an ideal study system to determine the population genetics of clownfish. In other words, how closely related are clownfish on the same reef? On neighboring reefs? On reefs across the Red Sea? These questions matter because Marine Protected Areas rely on the concept of preserving healthy marine habitats, and one indicator of a healthy habitat includes genetic diversity.
Red clownfish eggs on the reef wall, protected by the host anemone.
Clownfish are a perfect study system because their eggs are spawned demersally (and guarded by the parents), and their larvae spend a relatively short period of time in the plankton. Because adult clownfish always live within their host anemone, Michael can repeatedly sample the same fish and the fish won't move to a new location. So, day after day, dive after dive, Michael's team heads out on the boat to find Nemo--quite literally. Mae, Noah, Gerrit, Humberto, and Mike Sr. search for clownfish on anemones, gently catch them, take a tiny clip of their fin (like getting a haircut, the fin will grow back very quickly).
Mae Noble (KAUST) taking notes (left); A netted clownfish (right).
It takes a team of 5-6 people per site to collect 50 fin clips quickly and efficiently, and this team is amazing! Headed to each reef armed with nets, clipboards and tiny scissors, they give each clownfish a lucky fin. These fin clips contain enough genetic material for analysis to answer these important questions about population genetics and reef connectivity. These data will be among the first to document connectivity in careful detail for any species in the Red Sea.
"Lucky" tail fin after being clipped. Notice the fork in the tail which will grow back within days (left); Dr. Michael Berumen (right) taking notes on the clownfish after taking a small fin clip for genetic analysis.
Importantly, Nemo is already a poster species for ocean conservation since he has inspired so many people to care about the ocean and its denizens. However, this study could make Nemo a poster species for ocean conservation in the scientific community if we understand how much space is needed to maintain a healthy and diverse population. This Nemo connectivity study could thus help to inform the spatial planning of Marine Protected Areas - and may help to save Dori, Gill, Jacques, Bubbles, Bloat, Deb, Flo, Mister Ray, Peach, and everyone else. In the Pixar film, all of the reef creatures are working to save Nemo and to help him find his way home. Now, Nemo is returning the favor. As for these divers, "they have some serious thrill issues, dude," but they are "totally awesome."