Las Cruces

So today we headed out for Isla San Estaban. On the way there we saw a school of sierra mackerel just off of the boat dock. My first observations of the bay was that there were not many local fishermen out. The water temperature at the boat dock was 72.4 degrees Fahrenheit and the water depth is 19ft. The ocean bottom just off shore of the dock is sandy due to the sedimentation deposits of the Rio Sonora. In the morning the water was very turbid and we could not see the bottom even at a small depth of 19 feet.There was a beaufort scale of 0.

As we got out to cross between the mainland and into the channel between Isla Tiburon and Turner Island we saw one crab fisherman. As we went we saw patches of red algae ( water temperature of 67.3 degrees Fahrenheit at this point) which we speculated to be red tide.Ride tide is a common name for a biological occurrence where there are algae booms. Some of these red tides are natural and some are caused by nutrient loading. Either way red tides are not good for the environment. Many of the algae blooms are made up of plankton. Some species of plankton produce toxins which can be detrimental to other organisms such as fish, birds, and marine mammals.


We headed towards Isla San Esteban we came upon a group of long nose common dolphins. This group we estimated to include 80-120 individuals. After seeing these dolphins we realistized that it was not going to be possible to go to San Esteban due to the high winds. So we decided to go to Las Cruces which is a bay off of Isla Tiburon.

Las Cruces has significance for many different groups of people including: the military, the Seri and the current fishermen. The military built a small brick house right off of the beach. This shack is now used by fishermen. Before this, the Seris lived here up until the 1970s.

After we arrived at Las Cruces we were joined by a boat of fishermen. We discussed that they were probably illegally fishing because they were not fishing during the day. Most local fishermen fish only during the day so if they are out but not fishing they are probably diving for sea cucumber at night which is illegal.

Ben and Allen also did some of their San Esteban presentation but I will include this info when we do that trip.

We also got to snorkel here which was amazing. The area that we snorkeled in was slightly shallow to mid depth tide pools ( 3 to 10 ft ). This picture shows some of the area were went snorkeled and we also went around the point in the picture.

( I did not feel very well this day, so I was not abel to take in as more information as a wanted)