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The Revillagigedo Islands are located about 300 miles south of Cabo San Lucas.

Schooling Hammerheads used to be numerous in the islands.



Commercial fisherman often fish within the reserve - few are ever punished.


A Giant Pacific Manta slaughtered for its nearly worthless meat.



The remote Roca Partida is frequented by illegal commercial fisherman.


SeaWatch Report
Revillagigedo Islands Overview

Thirty years ago the Revillagigedo Islands were one of the richest archipelagos in the Eastern Pacific. World famous for the abundance of apex predators like hammerhead sharks, giant pacific mantas, and yellowfin tuna, these islands have been decimated by over-exploitation. What remains is greatly threatened.

“When I got to the islands 25 years ago,” says Mike McGettigan, founder of Sea Watch and one of the first people to extensively dive the area, “you would often be surrounded by several hundred sharks. We would see up to 100 wahoo at a time and often spend 45 minutes underwater with the same school of tuna swimming by. The schools would be miles long.”

That was then.

On the three inner islands of Socorro, Benedicto and Roca Partida:

• Wahoo populations have been devastated with the average weight of a fish around 20 lbs and populations down 70-80 % since the 1970s and down about 50% in the last 10 years with the biggest decreases coming in the last 5 years due to increased sportsfishing.

• Sharks have decreased 50-60% and many that are left have mouth injuries from hooks and are trailing long fishing lines.

• Yellowfin tuna populations have also dramatically declined over the past 20 years due mostly to tuna seiners that work the waters in and around the biosphere as well as the oceans just south of the Revillagigedo Islands.

• Reef fish like the Blue Jack, Rainbow runners and Leather Bass have also been heavily impacted by sportsfishing with populations down 30-40%.
(For sources see 2003 Survey Report & Fisherman Interviews.)

Uncontrolled commercial and to a lesser degree sportsfishing is the primary cause of these tragedies. These islands, as fragile and diverse as the Galapagos Islands, can be greatly impacted for years by a single longliner. Today, longliners operate without penalty in the Revillagigedo Islands…even though the Mexican government closed the islands to all commercial fishing in 2002!


Since it’s founding in 1993, SeaWatch has been bringing public attention to the destruction of these islands. A typical example is SeaWatch’s work following the St. Valentine’s Massacre.

At 9:00 a.m. on February 14th, 1994 the Unicap III, a Mexican Department of Fisheries boat, started pulling in their nets off the south end of San Benedicto. Passengers aboard SeaWatch’s floating headquarters, the Ambar III, watched helplessly as their worst fears came true.

Two of the mantas they had been riding the day before were hopelessly tangled in the nets. These gentle giants had fought the nets and been torn to pieces. Because of the damage to the nets, and to the mantas, those on the fishing boat decided it would be easier to cut their nets loose and throw them back in the water - entangled mantas, nets and all. When they left, there were thousands of feet of thin monofilament net all over the reef, still killing.

When they pulled in their long lines, there was nothing but reef sharks on the hooks. As these dead or dying sharks came up over the back of the boat, the lines were cut off above the hook and the hook and shark were dropped back into the water, where they immediately sank to the bottom. The underwater reef was littered with dozens of dead sharks. At that time they were selective as to which sharks had value and most sharks were just finned.

In all this killing, not one usable fish was caught.

In the meantime, another fishing boat, Mero VII, was busy harpooning the first manta that passed by their boat. The twenty-foot, one-ton manta was then gaffed with large hooks, and lifted out of the water, still very much alive, alongside the boat. Then the men got out in a small boat and proceeded to use axes to cut the wings off the still-living manta. In just a few hours over five tons of fish were killed near this pristine volcanic island, and many more were going to die in the discarded net. The two boats had nothing to show for all that carnage, except two, almost useless manta wings.
This world famous spot to ride mantas was forever changed in just 4 hours - divers from all over the world clamored to come and ride the gentle giants of San Benedicto. This senseless act cost millions of tourist dollars in the future.


Within days SeaWatch brought this senseless slaughter the attention of the Mexican public. The news was run three times on Guillermo Ortega’s influential Mexican TV news-magazine, Al Despartar, which is seen by 58 million Latinos. With the help of free-lance reporter, Armando Figaredo, SeaWatch made nine more Sea of Cortes specials for Al Despartar. The Manta slaughter was part of the national CBS Evening News in August and it became international news on CNN the same month.

Reaction was swift: Miguel Sanchez-Navarro and Mauricio Ruiz, President of Pronatura, the largest private Mexican ecology foundation, took the video of the killing of the Mantas directly to the Mexican President and the Head of Fisheries. Within two months, the Giant Pacific Manta was put on the endangered species list. It is now a crime to kill one [in the Revillagigedo Islands, punishable with a $10,000 fine.


Eight years of raising public awareness finally culminated in March of 2002 when SeaWatch and Miguel Sanchez-Navarro invited Secretary Santiago Creel, the minister in charge of the islands, to witness first hand the damage being done by illegal longliners and drift gill-netters. As a result of this trip and a lawsuit filed the year before by the Hotel and Sports Fishing Association of Cabo San Lucas, the entire biosphere was closed to all fishing as of March, 2002.

Unfortunately, this closure also included sports fishing. Though these boats had only a small environmental impact on the reserve, they provided an informal surveillance network. That network is now gone as they, of course, have followed the law while the large commercial operators have chosen to ignore it.

Today, the Revillagigedo Islands Biosphere remains primarily a park on paper only. While these Islands will never have the draw of the Galapagos, managed carefully they could be the one place in all Mexico that is a breeding ground for tuna and wahoo that could be brought back to pre-industrial fishing levels.

Unlike many parts of the world’s oceans, the Revillagigedo Islands fall entirely within the territorial limits of one country – there is no need for an international cooperation or legal framework to protect them. All that is needed is the political will to enforce the laws already on the books. And a little technology.

Today, SeaWatch, The Billfishfund, Pronatura and several other groups are actively working with the Mexican authorities to implement Vessel Monitoring System (VMS), an automated, satellite-based program to monitor geographically isolated areas similar to ones already in use in many countries including the U.S., Canada, and Chile.

Though holdouts remain, officials in the highest reaches of government have proclaimed their support for VMS, including the minister of Agriculture, Rural Development, and Fisheries, Javier Usabiaga. In order to see VMS and other reasonable management plans through to their completion, SeaWatch also has been helping to organize a coalition of like-minded interests, including representatives from the sports fishing and scuba diving companies, government officials, non-government organizations, leaders in the hotel industry, and prominent Mexico City businessmen.

This coalition, officially called the Comision Nautico~Recreativa y de Pesca Deportiva, has formal government backing and will have a seat at the table as various management plans for the Sea of Cortes and the Revillagigedo Islands are discussed.

Here are some things you can do to protect one of Mexico's last wild places include,

Join the Coalition
Support SeaWatch
Report Illegal Fishing Activity



Today longliners operate without penalty even though the Mexican government closed the islands to all commercial fishing in 2002.









In all this killing, not one usable fish was caught.

Sportsfishing boats had only a small environmental impact on the reserve but they provided an informal surveillance network.

It is now a crime to kill a Giant Pacific Manta in the Revillagigedo Islands.


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