El Bajo seamounts

El Bajo is a group of underwater sea mounts located roughly twenty seven nautical miles from La Paz and about ten nautical miles from Los Islotes, the sea lion colony off the north side of Isla Partida. Also known as the Marisla Seamount, it was named after a dive-cruise ship Marisla II (Mexican Flag), formerly USCG Cutter Columbine, owned by Maria Luisa Adcock and Richard M. Adcock. Richard was the first known sport diver, using SCUBA gear, to dive on the Seamount in 1957. This sea-mount is famous for its schooling scalloped hammerhead sharks, which occur in large numbers at certain points of the year. The dive site is made up of three different pinnacles running north-south with the northernmost pinnacle rising up to 24m/80ft, the middle 15m/50ft and the southern pinnacle 18m/60ft. Depths quickly drop off around the pinnacles reaching 550m/1,800ft within 800m / half a mile from the dive site.  

The center pinnacle (shallowest point) is the most popular, the south end is a vertical wall from 15m/50ft to 30m/110ft, at the base a large sandy channel frequented by pelagics. The top of the peak is a series of channels in about 20m/65ft of water, channels big enough to swim through and inhabited by large numbers of panamic moray eels, colorful gorgonians and small sea fans. There are several small caves at the base of the seamount (100') and larger soft coral colonies found in the deeper depths. Due to the cold water up-welling from the depths this dive site is a magnet for large schools of fish and pelagics, including marlin, jacks, dorado, tuna, manta and mobula rays.

The hammerhead sharks that frequent these pinnacles are Sphyrna lewini, the scalloped hammerhead. They can occur in large schools or be spotted individually, typically the late summer and fall is the best time. Scientists are not positive why they exhibit this schooling behavior but the most popular theory is mating. The schools of hammerhead sharks can be seen throughout the year, perhaps there are more sightings in the late summer and fall simply because that is high season for scuba diving in the La Paz area.

  El Bajo is an advanced dive site with depths over 18m/60ft and is subject to open ocean conditions. Scuba diving trips to this dive site are weather dependent.