Biosphere Reserve El Vizcaino (115) 7 17 77

Centro de Investigaciones Biologicas del Noroeste (CIBNOR) Tel (1) 125-36-33 FAX (1) 125 47 15

By federal decree, on 11 September 1972, Lagunas San Ignacio and Ojo de Liebre were designated as "Zones of Reserve and refuge of Migratory Birds and other Wildlife".

Another decree, on 16 July 1979 designated this lagoon as "Refuge for Gravid Whales and Cubs and Zone of Maritime touring attraction". Laguna San Ignacio is part of the Biosphere Reserve El Vizcaino (2,546,790.25 ha), decree on 30 November 1988.

Scattered cattle ranches along the tributaries of the watershed

Laguna San Ignacio, but very often they dry (because of infiltration) before they reaching the shoreline. The only permanent arroyo in the area is arroyo San Ignacio, but with no influence on the surrounding area.

The aquifers recharged by the subwatersheds laguna San Ignacio and Rio San Ignacio are in equilibrium or with some available water. San Ignacio subwatershed, has 3.5 millions m³ available, based on estimeates that recharge is 8.5, whereas extraction is 5.0 millions m³

At Estero El Cardón, mean values were 5.22-5.46 ml/lt. Range was from 3.58 to 9.9 ml/lt..

There is a channel

6 m deep and 680 m wide, that crosses the banks to access the lagoon. About 4 km north of Punta Bronaugh, where the lagoons widens, the channel also enlarges to an area of 2 km² and between 9 and 14 m deep. Starting from this zone, there are three channels, the principal one is 3.75 km long and in average 6 m deep, it goes toward the head of the lagoon. The head of the lagoon has extensive areas subject to flooding.

Thirteen species of algae, were reported for Laguna San Ignacio between 1953 and 1961, but no specific location or date of collection was mentioned.

In a 1994 study, 30 species of algae are listed, some of them with commercial value such as Gelidium spp and Euchemia spp.

A 1995 study listed 31 species of algae for the west coast of the El Vizcaino Biosphere Reserve distributed between open littoral and inner littoral.

An 1992-1993 study on the phycological flora of the lagoon, reported

85 species. Of these, 48 were Rhodophyceae (56.5%), 21 Chlorophyceae (24.7%), 14 Phaeophyceae (16.5%) and two Cyanophyceae (2.3%). Seventy-six species were first records for the site. Laguna San Ignacio hosts extensive areas of sea grass Zostera marina, principal food for the Black Brant (Branta bernicla). Other species from the submerged zones include: Ruppia maritima and Phyllospadix scouleri.

A 1983 study on the phytoplancton of Estero El Cardon, reported 139 species, out of which 55 were centric diatoms, 65 penned diatoms and 19 flagellades. Phytoplancton showed in patches with higher densities in the interior part of the estero during November and December.

Toward the interior of the lagoon there exist extensive areas of saltmarsh. This vegetation is mostly represented by: Batis maritima, Salicornia bigelovii, Spartina foliosa and Monanthochloe littoralis.

Considerable extensions of mangrove are found at the entrance to the mouth of the lagoon, and at the Esteros El Cardon, La Pitahaya and El Delgadito, south of the mouth of the lagoon.

In a 1972-1975 sample of dune vegetation Abronia maritima was found along the entire coast. This species is the major foredune builder and it is joined at the central sector of the peninsula by Sesuvium portulacastrum.

A 1994 study showed that the most dominant mangrove species were: Laguncularia racemosa in flooded areas and Rhizopohora mangle in permanent inundated zones. Other species associated to this type of vegetation are Salicornia virginica, Salicornia subterminalis, Batis maritima, Monanthochloe littoralis, Atriplex sp, Suaeda mexicana, Mesembryanthemum crystallinum, Abronia maritima and Distichlis spicata.

Coastal dune vegetation varies, but the most commonly found species are: Abronia maritima, Abronia gracilis, Ambrosia dumosa, Atriplex barclayana, Atriplex canescens, Dalea maritima, Mesembryanthemum crystallinum, Salicornia spp. and Distichlis spicata.

The hallophytic matorral is the least diverse and it is represented by the Atriplex spp. association, the most abundant species are: Atriplex barclayana (58%), Atriplex canescens (29.41%), and Encelia sp. (11.76%).

A total of 20 species of ducks and one specie of brant winters in Laguna San Ignacio.The average numbers of ducks anually recorded between 1977-1978 were 5,289. Between 1954 and 1989, the average number of wintering brant (Branta bernicla nigricans) in this site was 33,278. During a 1988 and 1989 study, a total of 54 species of birds were recorded at San Ignacio Lagoon, 44 were observed at ballena island. Nine waterbird species breed on this island. A 1991-1992 survey of Snowy plover (Charadrius alexandrinus) reported a total of 1344 adults in 16 localities, of these, 378 (28% ) were found in the Laguna San Ignacio complex.

A 1991-1994 survey estimated 354,900 wintering shorebirds in wetlands on the west coast of Baja California. Of these, 8.9 % were located in the Laguna San Ignacio complex. A total of 31,542 wintering shorebirds were estimated in January 1993, with large species making up 27.7%, medium 10.3.0% and small 62.1% of the total.

San Ignacio complex is a major wintering site for Brant (>33,000) and Shorebirds (32,000).

A 1994 study, listed a total of 173 species of birds. Within seabirds the most abundant are Gaviformes, such as Gavia pacifica and Gavia immer; and

Pelecaniformes, such as Pelecanus occidentalis and Phallacrocorax auritus; and Anseriformes, principally the Black Brant Branta bernicla. The dominant coastal species were: Ciconiformes, Gruiformes and Charadriformes. Breeding waterbirds include: Egretta thula, Egretta tricolor, Egretta rufescens, Nicticorax nicticorax, Larus occidentalis, Sterna maxima, Falco peregrinus and Pandion haliaetus. The osprey colony is considered the world densest nesting population (180 breeding pairs). Among the raptors, other species include Buteo jamaicensis and Falco sparverius. Common upland species include Callipepla californica, Zenaida Macroura, Geococcyx californicus among others.

A 1993 study presented the first fish check-list for this area, 81 species of fish were recorded, some were drawn from analysis of the diet of seven species of fish-eating birds. In 1998 the 1993 check-list was updated, with the addition of 26 species, the current list includes a total of 107 species.

Another study in 1994, reported a total of 107 species of fish for Laguna San Ignacio and its environs. Of these, 12 species are considered as rare. The list also includes 34 species of temperate origin as well as 27 from the tropics.

A 1990 study, estimated 300-400 gray whales (Eschrichtius robustus), in the lagoon.

The adjacent area to Laguna San Ignacio is part of the historical distribution range of the peninsular pronghorn (Antilocapra americana peninsularis), and although this area is not longer considered part of the current range, on 27 May 1992 a couple of pronghorns were sighted near the area known as El Medano Amarillo, northeast of the lagoon.

Bird and whale-watching activities are regulated but no enforced.