La Paz / by Michael Johns

The Pacific Seabird Group puts on an annual conference to bring together scientists and students studying seabirds around the Pacific. Last year the conference was held in rainy Tacoma Washington. This year it was held in sunny La Paz, on the southern end of Baja California Mexico (see map below). I used the timing and location of this year's conference to give a talk on my double brooding work with Cassin's auklets, and take a much needed vacation from Fairbanks with Casey before I head out to the Farallones for another summer field season. Once the conference ended, we spent much of our time wading through the thigh-deep turquoise water of Balandra Beach, lounging in the sand, hiking among cacti, birding the Malecon, and drinking margaritas. 

The highlight of our trip was the chance to swim with the world's largest fish, the whale shark. These massive filter feeders can reach lengths of up to 40 feet, and are found in warm tropical waters throughout the world. According to a paper by Ramírez-Macías and colleagues published in 2012, La Paz is one of several sites in the Sea of Cortez where predominately juvenile whale sharks congregate to feed in shallow plankton-rich waters. The site is a short panga ride from La Paz, on the north side of a long sand spit called El Mogote. We spent roughly 40 minutes watching a small (20 foot?) male slowly strain tiny plankton from the surface waters, which during this time of year felt less tropical and more temperate. The photo below was taken in Bahia de los Angeles, another important juvenile staging area further north, during my first encounter with whale sharks in 2006. 

The images above, in order of appearance are: marbled godwits, magnificent frigatebird, tricolored heron, reddish egret, yellow-footed gull (eating a puffer fish), unknown mangrove crab, parade of brown nudibranchs found at low tide in the mangroves (presumably breeding). 

Map of Baja California created with ggplot2 in R. Colored regions indicate topography of land, grays indicate bathymetry of the sea, for those not familiar with the region. La Paz is tucked away on a shallow bay at the southern tip on the Sea of Cortez side. The color pallette for this plot was inspired by the local geology.