The coastal waters of Baja California Sur (BCS), Mexico serve as feeding and developmental ground for five species of sea turtles: the loggerhead turtle (Caretta caretta), the black turtle (Chelonia mydas agassizii), the hawksbill turtle (Eretmochelys imbricata), the olive-ridley turtle (Lepidochelys olivacea) and the leatherback turtle (Dermochelys coriacea). Although sea turtles are protected in Mexican waters since 1990 by presidential decree, illegal and incidental fishing rates are still very high especially in the region of BCS, as turtle meat and eggs are still considered a delicacy in many areas, thus impeding population recovery.
This project is designed to obtain information on minimum sea turtle mortality rates, quantify the ratio between juveniles and adults in the catch, identify the species which are most affected, and point out areas, seasons and fishing gear that most affect sea turtle populations. The information collected through the interviews will allow us to 1) identify stakeholders, 2) determine cultural and economic importance of sea turtles in the local communities, and 3) identify whether there exist correlations between sea turtle fishing/consumption and the socio-economic situation and education of the local population.
This information, which is unavailable at present, is critical for the development of a new strategy for the conservation of sea turtles. Thus we hope to provide a useful tool that could be used by the administrators in the decision making process and help this way with the protection of these animals in the state of Baja California Sur.
Project Update April 2006 Evidence of illegal fishing: in some places there still are “guateros” (illegal fishers).
At the beginning of March 2006 we started our sea turtle mortality census and visited beaches, villages and dump-sites in 6 of the15 monitoring areas. Up to now we found more than 150 carapaces, 53% of these being found buried in dump-sites. This is pretty negative sign as it indicates that sea turtle consumption is still high in the state of BCS. Furthermore more than 50%of the “consumed” carapaces have been identified as black turtles (Chelonia mydas agassizii). Black turtles are considered more “tasty” and have been a target species between the 50s and 80s, when sea turtle exploitation was still legal in Mexico. Another negative finding is that more than 70% of the turtle found dead were juveniles.
On the other hand, positive outputs came from the interviews and long talks with people from the communities. As preliminary conclusion it can be said that in general people are well informed about sea turtle status and the consumption of sea turtle meat, even if still high, is sharply declining, hypothesis supported by the fact that a lot of children have never eaten sea turtle meat.
We are currently working on fishing effort data to both analyze artesanal fishery/sea turtle mortality correlation and identify highly dangerous fishing gears.
Project Update May 2006 During May 2006 we monitored the North Pacific coast of Baja California Sur.
Totally we found 80 carapaces belonging to 4 species, no leatherback turtle has been found. Causes of death have been identified as being consumption for
During the month of June we will visit the North Gulf coast of Baja California Sur so that to complete the preliminary monitoring of all the sites.
Solid network has been established with staff from the Vizcaino Biosphere Reserve and fishermen from San Ignacio lagoon and Punta Abreojos. The idea is that they will conduct the mortality census every month and we will join them once every two months. They have been trained and received all the equipment needed for the monitoring.
Project Update June 2006 During the month of June we completed the preliminary mortality census as we visited the North Gulf coast of Baja California Sur. This included sites like Santa Rosalia, Mulegé and Loreto.
Few carapaces have been observed in this area although the consumption rate is known to be very high. Santa Rosalia in particular is known to be the start point of an intense black market of sea turtle meat that is usually transported to Tijuana and San Diego. In Santa Rosalia we met a group of fishermen who are interested in collaborating with us. During our next visit which probably will be on July, they will take us to hidden beaches where a small group of guateros (sea turtle catchers) is still operating. We had extensive talk with these fishermen and they helped us define the fishing area of Santa Rosalia and the feeding are used by sea turtles (black turtles in
In Mulegé there is a small NGO working for sea turtle protection called “Los Eco-amigos de Mulegé”. They have very small funds but are working hard to protect sea turtles. At the moment they have established solid relationship with three fishermen that are helping them identifying sea turtle camps. We decided that we will work jointly with them. The deal is that we will go every two months in Mulegé and will organize short talks and presentations for both children and adults. In exchange they will lead mortality census once per month following our protocol.
Loreto is hosting a Marine National Park. We went monitoring some beaches with the park authority. We didn’t find any carapaces on the beaches but a few have been discovered at the dump-site and in an abandoned fishing camp.
Project Update July 2006 During the month of July we visited the southern part of Baja California Sur.
The four sites are known as Olive-Ridely turtle nesting site. Different NGO are working in the area to protect nests and eggs from poachers.
Thanks to a scholarship offered by the Society for Conservation GIS, a member of Proyecto Carapacho team could join an intensive GIS course to improve her skills on GIS analysis and techniques.
Project Update October 2006 A loggerhead turtle (Caretta caretta) stranded on Santo Domingo Island
The hurricane John affected the coast of Baja California Sur by the end of August and had a strong impact on some of our monitoring sites, impeding the access to certain areas and beaches. The situation came back to normal by mid-September and we were able to go on with our sea turtle mortality census.
Monitoring the small island of Santo Domingo, located in Bahia Magdalena on the Pacific side, we found 23 stranded loggerhead turtles (Caretta caretta).
According to the status of barnacles on their carapaces, most of them stranded in the previous 24-36h (barnacles were still alive when we checked them), but the turtles were in a high degree of decomposition suggesting that death occurred days before at sea. Talking to other researchers operating in a closed area, we discovered that they found more than 70 sea turtles stranded in less than 20 days. This event has no explanation at the moment. Fishermen were also enquiring as this area is known for having a high rate of illegal catch. We were told that nobody is fishing with nets at present reducing the risk for sea turtles. Furthermore turtles didn’t present any external sign of sickness (the most common being the fibropapilloma). We can just suggest some hypothesis concerning these unusual strandings: a boat operating very far from the coast, the hurricane John or a disease. We collected tissue samples that will be analyzed and asked for a veterinary to do some necropsy to find out the real cause of death.
Project Update November 2006 The month of October has been quite full of events. The saddest one occurred and is still occurring in Puerto Adolfo Lopez Mateos, a fishing community in Bahia Magdalena, where more than 700 sea turtles stranded without apparent reason. Different studies are currently ongoing to identify the possible cause of such a huge mortality. We also discovered some dead marine mammals and a lot of fish. At present we just can make hypothesis concerning such mortality:
A happier event is the meeting we organized with the EcoAmigos of Mulegé (Eco-Friends of Mulegé) which is a small association of young people decided to conserve their environment. The meeting was successful and we invited all the members to join us for a beach census during which we found a nest and a sea turtle carapace. We also discussed about further cooperation and we accorded that we will meet every two months and will share our experiences.
We also had an interesting meeting with employees of the Marine national Park Bahia de Loreto. No dead turtles were found meaning that the park authority is doing a good job in informing people and prevent illegal catch.
Furthermore we had the chance to monitor Isla Arena, up to the north of Baja California Sur in the Biosphere Reserve of El Vizcaino. Again with the support of people working for the protected area we monitored the beaches and organized a “cleaning campaign”, inviting all the citizens of Guerrero Negro to clean their yards and give us their carapaces. The campaign was a success as more than 30 carapaces were collected. Guerrero Negro is a well-known area for illegal hunting of sea turtles and we hope that organizing more events we will be able to contribute to the reduction of sea turtle illegal catch.
Project Update December 2006 After two months of very intensive sea turtle strandings in the aera of Bahia Magdalena, it seems that the situation has now become normal again. A few necropsies have been realized on fresh stranded turtles by specialists come from Mexico City, as in Baja California Sur we do not have the necessary equipment. Preliminary results showed a high rate of cadmium (Cd) in sea turtle tissues. The cadmium is naturally present at high rates in Baja California beaches on rocky shores, it is evident that with the erosion process most of this cadmium is transferred to the beaches and can be easily washed away during special climatic events (like the hurricane John).
In animals and human beings cadmium is considered as highly toxic and is known to bioaccumulate. Nevertheless, there is no evidence that the cadmium was present in all the stranded animals. At present the most probable hypothesis is that these strandings are due to interaction with fishing vessels operating in international waters. We are now trying to get a metal detector to verify the presence of hooks in sea turtle stomachs.
Other activities that have been organized during the month of November and December are:
We are now preparing a presentation for the 9th Annual Meeting of the Sea Turtle Network of Las Californias that will take place in Loreto at the end of January.
Final Report Read full details of the actvities and findings of this project in the final report below.
