Reason #1 not to focus too heavily on studying bleached corals (lower left).

In order to collect data on the “benthic” or bottom cover of a reef, you must spend the majority of the dive swimming < 1-2 metres above the bottom and looking down. My Kiribati dive colleagues and I like to joke about what swims by when we’re not paying attention. On one dive during this recent trip, I watched a small reef shark swim wide circles – harmlessly, I should add – around my dive buddy Toaea, who was focused on taking bottom photos. On a subsequent dive, Toaea watched a barracuda – also harmless – float above oblivious me as I measured some tiny corals buried in the reef.

The photo of this bull shark was actually taken on a recreational dive in Fiji — so, at least this time, everyone saw the shark. I took advantage of the necessary layover on the way to Kiribati to test some gear and investigate a minor bleaching event. Water temperatures were elevated more than usual around most of the Fiji islands during the Southern Hemisphere summer. The temperature spike was enough to trigger bleaching warnings from the NOAA Coral Reef Watch system. A lot of corals, like the small Acropora in this photo, remained bleached in April.

This is part of a series of posts featuring stories, photos and video from a recent field research trip to Kiribati.

What explains the amazing rock formations on coasts of Kiribati?

Fluke coral growth? Ancient rock art like the Nazca Lines? Photoshop?

They are te ma – traditional fish traps – built from pieces of rock or coral collected along the shoreline.

When the tide is in, fish can swim along the “shaft” or through a direct entrance into the heart- or arrowhead-shaped openings.

When the tide recedes again, fish get trapped there and are easy prey. The shaft also helps point people to the place to collect the fish.

These traps can be found at Temaiku, the SE tip of Tarawa, just south of the airstrip.

by Simon Donner

Northern elephant seals come ashore in late fall every year in California’s Año Nuevo State Park to mate and to do battle. The videos below were taken in mid-December, after the American Geophysical Union Fall meeting.

Here’s a video of an seal coming ashore, slowly.

These are no ordinary seals. They are built more like whales or, as my nephews might say, Jabba the Hut. A bull elephant seal can weigh up to 2500 kg and be four to five meters long.

They can move surprisingly fast on land too, up to 10 km/hr, but only in short bursts. An elephant seal wouldn’t beat you in a 100 m sprint, but it would certainly commit a lane violation and crush you, and probably the rest of the runners, before anyone got out of the starting blocks.

Here’s a little scuffle between two bulls, one making the signature guttural grunt.

Finally, here are some young males “rushing” up the beach to avoid an adult male. This clip needs narration from John Cleese.