Located in the Bay of La Paz, the islands in the Espiritu Santo archipelago and the surrounding waters provide habitat for algae, fish, mammals, marine birds and invertebrates, including some species at risk and 38 species of plants and animals that are not found anywhere else in the world. They constitute a feeding and refuge site for various aquatic species and a stopping place along the migratory routes of hammerhead sharks and sea turtles. The archipilago is an important site for fishing, tourism and research. In 2005 these islands became part of UNESCO’s World Heritage of Humanity sites.
QuestionTo what extents are altered nutrient loads affecting ecosystem health and how are they changing?
Why This Score?Selected conditions may preclude full development of living resource assemblages and habitats, but they are not likely to cause substantial or persistent declines.
Basis of JudgementThe coves along the Espiritu Santo Island coastline are ideal for capturing phosphorous concentrations, since they are natural sites of deposition and therefore are more sensitive and vulnerable to the eutrophication process. The association between nutrients and the proliferation of toxic microalgae, domoic acid and dinoflagellates has been studied; an increase in jellyfish is associated with concentrations of nutrients and organic material. There is documentation of marine algae introduced in the area, and covering larger areas each year, likely due to an increase in nutrients in marine water.
Clear evidence is insufficient for assessing a trend—there is only enough to suggest that the ecosystem is changing. An example is the phenomenon of increasing volumes of water with minimum oxygen levels from the tropical eastern Pacific region along the coasts of Nayarit. However, elements that might confirm this as a trend in the area around the park are not clearly established.
QuestionTo what extent do water conditions pose risks to human health and how are they changing?
Why This Score?Selected conditions that have the potential to affect human health may exist, but human impacts have not been reported.
Basis of JudgementIn 2006, cases of red tides affecting human health were documented in the area (leading to the suspension of fishing activities for approximately one month), but there is no evidence that the toxins came from the immediate vicinity of the island and instead appear to come from the Bay of La Paz. This indicates that the condition of water in the park is good. Red tides can potentially affect human health, but there is no clear evidence that this is taking place in a consistent pattern.
The connection between anthropogenic activities and red tides is unknown. What is certain is that the city has grown exponentially in the last six years and this can clearly be expected to have repercussions on the bay’s health. The magnitude of possible effects, however, is unknown.
QuestionTo what extent do human activities influence water quality and inputs and how are they changing?
Why This Score?Some potentially harmful activities exist, but they do not appear to have had a negative effect on water quality and inputs.
Basis of JudgementThe trend from the Coastal Environmental Quality Index (Índice de Calidad Ambiental Costero—ICAC), estimated from coves located in the Bay of La Paz (2007), indicates that water quality is good and that the same is likely true for Espiritu Santo Island, although an excess of the nutrient orthophosphate (PO4) makes it vulnerable to eutrophication. Evidence of water with high levels of fertilizers draining from rivers along the coastline of the Sonora and Sinaloa side of the bay, as well as a notable increase in isotopic nitrogen found in the hair of Los Islotes sea lions since 2002, are indicators of a trend toward the eutrophication of vast areas of the southern part of the Gulf of California. Population growth in the city of La Paz intensifies other factors affecting the park’s water quality, including discharges of hydrocarbons from oil tankers and increasing numbers of tourist boats, as well as untreated wastewater.
The sea surface temperature may increase in the short and medium term, and O2 concentration may decrease, due to expansion of areas from the tropical eastern Pacific region with minimal concentrations of O2, and this may lead to changes in the distribution of fauna.
Why This Score?
Basis of Judgement
Extent and Distribution
QuestionTo what extent does habitat alteration, including the extent and distribution of major habitat types, affect ecosystem health, and how is it changing?
Why This Score?Selected habitat alteration may inhibit the development of assemblages, and may cause measurable but not severe declines in living resources or water quality.
Basis of JudgementSince the marine area was decreed a protected area, disturbances of the rocky bottoms that were adversely affecting park habitats were eliminated. In the case of corals, these disturbances were caused by discarded junk carried out to sea during hurricanes, or by dredging conducted by large shrimp boats. A recovery process continues, and while some sites require more stringent protection measures, the situation is not expected to worsen, given the new conservation and management program to be implemented.
QuestionTo what extent do contaminants in habitats affect living resources or water quality, and how are they changing?
Why This Score?Information is insufficient or the question is not applicable.
Basis of JudgementDischarges from the rivers along the opposite coastline, lack of clarity regarding the exact relationship between anthropogenic activities and red tides, and the spread of invasive marine algae (caused by the trend toward eutrophication), all suggest that the ecosystem is changing. However, there are not enough elements to identify an ongoing impact from contamination in the Espiritu Santo Archipelago National Park. Studies on the presence of heavy metals in mollusks and the accumulation of mercury in pelagic species in the Bay of La Paz are still underway.
QuestionTo what extent do human activities influence habitat extent and quality, and how are they changing?
Why This Score?Selected activities have resulted in measurable habitat impacts, but evidence suggests the effects are localized, not widespread.
Basis of JudgementNo substantial changes have taken place in the park’s habitat during the last 20 years. The main impacts suffered are highly localized and have not spread further. Modifications produced in the habitat, for good or ill, come from sunken ships that are being transformed into artificial reefs; the anchoring of boats; spills occurring when ships or ferries run aground; some unauthorized and artisanal fishing methods ("ghost fishing" in El Bajo, to the north of Espiritu Santo Island; and shrimp trawling that was practiced regularly ten years ago, the effect of which has not been evaluated); over-fishing; the increase in activities and impacts of recreational visitors; and the collection of souvenirs in the parks’ core areas. The rocky substrate and corals, in particular, have suffered structural habitat loss.
It is not clear whether changes in the habitat fall within normal limits, but the perception of fishermen operating within the park is that fish stocks are diminishing in specific areas, such as San Gabriel Bay and off La Ballena island. This may be attributable to illegal fishing. Also, fishermen warn of increasing vulnerability in sites where red snapper is caught.
Anthropogenic activities are unavoidable, but their impacts on habitat should be controlled with more robust management methods. If this does not occur, it is likely that serious problems will arise in relation to habitat quality.
So far, the protection-oriented actions implemented have been key to preventing decline of the habitat, and the planned park management and conservation program will certainly contribute to improving the habitat.
Scorecards 1 to 10 were developed in 2007-2008. Scorecards 11 and 12 were developed in 2010.
The islands in the Espiritu Santo archipelago and the surrounding waters together form one of the Gulf of California sites with the greatest biodiversity and productivity. The extraordinary natural wealth and scenic beauty of this national park play a fundamental role in the economic activities in the city of La Paz, particularly in the fishing and tourism sectors. Although the islands are not permanently inhabited, they are visited by groups of commercial fishermen and various tourism companies that bring large numbers of national and foreign visitors. Also, every year various researchers conduct important studies in this area.
Located in the Bay of La Paz, this national park represents the largest body of water within the physiography of the Gulf of California. It thus has particular oceanographic conditions for the specific concentration of photosynthetic pigments that set it apart from the rest of the Gulf. A great biodiversity of fish, mammals, marine birds and invertebrates, 38 species of plants and animals that are not found anywhere else in the world inhabit the archipelago, along with a colony of sea lions. There are approximately 284 species of algae (red, green and brown), 24 percent of which are endemic to the Bay of La Paz, as well as a great diversity of habitats, including mangroves, sandy bottoms, rocky reefs, marshes, beaches, bays and rhodolith beds, which are characterized by a high degree of ecological integrity. This is a feeding and refuge site for various aquatic species that are representative of the Gulf of California’s extensive marine biodiversity, and a stopping place along the migratory routes of the hammerhead shark and five species of sea turtles, making this park an important national site. In addition, some important species included in risk categories specified in Mexican Official Standard NOM-059-Semarnat-2001 are found here.
Use of the archipelago dates back to pre-Hispanic times when the islands were inhabited by groups of Pericúe indigenous people, as evidenced by important archeological remains in the island complex. In the early 20th century, the first and most important aquatic center for the production of oyster pearls, developed by Gastón Vives, was established on Espiritu Santo Island.
In 2005 these islands and other natural protected areas of the Gulf of California were included in UNESCO’s list of World Heritage of Humanity sites.
State(s) or Province(s):
Baja California Sur