23. Bahía Magdalena

Site Overview

Bahía Magdalena is situated midway along the Pacific Baja California Sur coastline. This large bay is the largest wetland ecosystem on the west coast of Baja California. It is more than 50 kilometers (31 miles) long and is lined by barrier islands that protect the bay from the harsh Pacific waves. It is the shape of one of these islands, Isla Magdalena, which forms Cabo San Lázaro.

Lagoons and wetlands line Bahía Magdalena and kelp forests can be found along the southern end. This area is considered part of the biogeographic transition zone from temperate to tropical climates and is, therefore, nearly the northern-most extent of mangroves along the North American Pacific Coast. Coastal upwelling enhances the retention zone that the barrier islands and currents provide, and leads to a high level of productivity and diversity in the area. Attempts by the government to establish aquaculture for shrimp, fish and giant Pacific oysters have been unsuccessful, due to both environmental and also structural problems. Attempts at cultivating the native pearl oyster (Pteria sterna) are now underway. Much of the human population surrounding Bahía Magdalena relies on fisheries for such species as sardine, shrimp, squid (Loligo spp.), red crab (Pleuroncodes planipes) and abalone. Despite community dependence on fisheries, many are in decline, including those for long-lived, large species such as rockfish, swordfish and tuna.

Green and loggerhead turtles are among the species that feed in Bahía Magdalena, one of their key habitats. Some of the green turtle populations are resident, though loggerhead juveniles migrate to the area to feed on seasonally abundant red crabs. Leatherback turtles (Dermochelys coriacea) are also occasionally sighted during the fall and winter. Heermann’s gulls migrate to the area to breed during the winter, and pink-footed shearwaters spend their summers using the productivity of the area after migrating north from Chile (Harrison 1983). The wetland harbors the northernmost breeding colony of the magnificent frigatebird (Fregata magnificens) and the southernmost breeding site of the bald eagle (Haliaeetus leucocephalus). Brown pelicans that migrate north into California also breed here.

Magdalena is one of the most important destinations for blue and gray whales as they finish their migration from the Alaskan and Arctic feeding habitats. In the warm waters of the bay and the Santo Domingo Channel, they breed and calve during the winter months, making the region an increasingly popular tourist destination. Both Bahía Magdalena and Santo Domingo
Channel are key breeding and calving habitats for the gray whale.

Certain threats in Bahía Magdalena are worsening with time, including exploitation of natural resources and coastal pollution. Damaging recreational use and ecotourism, such as birding and whale watching, continue to rise.