The breeding status and habitat selection of the California Least Tern was studied in four colonies of Baja California during 1989 and 1990. In 1991, a survey of its breeding population was done and 250 breeding pairs were found in the state. It was confirmed that the breeding functional unit of this species is the congregation (more than one nesting site was found at each wetland). Natural disturbances such as high tides and predators may destroy 15-69% of the nests, whereas human disturbance, such as all-terrain vehicles on the nesting sites, can destroy 88-100% of the nests, and it is the disturbance to be managed. The preferred breeding habitat for the species was a combination of open and vegetated areas, moderate cover of debris, and the presence of landmarks close to the nest. Barrier beaches were considered optimum habitat, whereas flats subject to flooding were suboptimal breeeding habitats. The document includes a list of known Least Tern colonies along the peninsula of Baja California.

This paper present the geological setting for a comprehesive ecologic study of a small coastal bay. The samples and observations upon wich the conclusions are based were collected during a series of field excursions. The bay floor samples were collected with a bottom grab of the Hayward type and split in the field to provide samples for both biological and geological analyses. Several piston core samples of the bayshore marsh deposits were obtained, and split and described in the field. Selected sections of the cores were sampled for later laboratory analysis and radiocarbon dating.

The hydrological behavior or the Santo Domingo Stream is analyzed through this work, trying to decide the more convenient type of work between a storage dam and a derivation dam in order to obtain the best utilization of the superficial drippings in the agriculture. Several alternatives are being analyzed for storage capacity and derivation, defining for each one the more convenient, according with their efficiency to satisfy the irrigation demands of a proposed zone.

In Baja California the Acuaculture is considered as one of the most viable activities for the food production, and also for the regional development; the San Quintin Bay, is an area with exceptional characteristics to develop this activity. In 1985 a feasibility study was done for the creation of an acuaculture district, in the San Quintín Bay area. The main object for the Acuaculture districts is the preservation and betterment or the natural conditions of the national property waters, for the promotion and exploitation of the marine species, plants and animals, and the salts and minerals. The San Quintín zone is used mainly for the commercial farming of the japanese oyster (Crassostrea gigas) and the fishing of macroalgae (Gelidium Robustum y Gigartina canaliculata), pismo clam (Tivela stultorum) and mussel (mytilus californicus). This study includes an analysis of the characteristics or the primary productivity, research done, oyster harvesting, biotechnology, levels of production, infrastructure, support systems, industry, commercialization and product perspectives, economic (derrama), financing, contamination and development plans for this area. It is concluded that San Quintin Bay shows proper conditions for the realization of acuaculture activities with filter-feeding organism and it is considered that the creation of an Acuaculture District as one of the most feasible alternatives to the conservancy and support for the area’s acuaculture development.

This plan was done in 1988. Its main purposes are: based on Lázaro Cárdenas San Quintín actual information, its population characteristics, and as of their resources and potential, the use of ground ordinance could be established and also the human settlements regulation and orientation, defines use and destiny of the ground. It also proposes the regulation of use and profit of its natural resources, specially water, in order to preserve the area’s ecological balance and control the growth of the urban area. It adjusts to the natural environment, and the growth possibilities of the infrastructure to avoid the invasion of areas such as the agricultural ones.

San Quintin, Mexico provides a useful research site for integrated analysis of material fluxes and socioeconomic constraints in a geographically isolated system. Natural resource utilization on the land is dominated by exploitation of grounwater for cultivatión of horticultural crops (primarily tomatos). Irrigation exceeds groundwater recharge minus water export by a factor of 6 resource utilization in the bay is dominated by oyster culture and the food for the oysters is provided by tidal exchange of water and organic materials. A consideration of oyster respiration versus system respiration suggests that the present level of aquaculture is about 40 % of the sustainable level. A "physical unsustainability index" (PhUI), was developed to measure the proportional, departure of utilization of the most limiting resource from sustainability: 6 on land: 0.4 in the bay. Based on a consideration of PhUI and measures of economic development in this system, we conclude that the aquaculture is more viable than agriculture.

For this work, extensive and intensive traveling was done in the area of San Quintin (Punta Mazo y Punta Azufre) to gather information about the possibility of existence of archeological sites, to determine its cultural importance to propose its preservation and study. Seven sites of archeological interest were registered around Punta Mazo area. About Punta Azufre seven sites with prehistoric human activity were detected, specially in the dunes and it probably refers to a sole very wide shell middem. The work suggests that no construct ion authorization should be given to any development that affects these shell middems, as it is said in the Federal Law for monuments and archeological zones, artistic and historical and its regulation in effect.

This document was elaborated as a Proposal to established a Protected Area in Bahia San Quintin. It was presented to SEDUE (Secretary of Urban Development and Ecology). It contain relevant information of its physical characteristics such as: Physiography , topography , physical and historical geology. Types of soil and related information of the hydrology and meteorological characteristics of the Bay. It also contains lists of flora and fauna. Makes an historical review of the activities that have been done in the Valley and in the San Quintín Bay, reporting amounts of production of the socioeconomic and population data. Besides giving a list of the works done in the area, including their resumes.

This work presents the results for the use of underground waters use, underground hydraulic measurements, determine the surface and the type of crop in which the exploited water should be used. It also contains information about the grade of actual exploitation from the San Quintín watershed. Measures the storage underground water for the administration alternative projects application. Defines the areas with bigger gehidrologicas possibilities and delimits the zones with poor quality of underground water, besides providing information of the exploitation with high concentrations of total dissolved solids.

The present survey of Bahia de San Quintin in Baja California fulfills two primary purposes: a search for basic information on an unpolluted enclosure as near southern California as posible, and the initiation of comparative investigations. This report forms an introduction to a series of articles to be published on the geology, hidrography and benthic life of the bay, an includes those descriptive features not being treated elsewhere.

Algae and Eel grass were collected by SCUBA diving, wading in tidal shallows and shore collecting. So few algae were recovered in the benthic grab samples that is belived that most of these algae in the bay are concentrated in a narrow belt forming the margin of the bay. A transect of samples was made across the northwestern marsh of the east arm starting on bare soil at the edge of the marshe next to a dirt road. Eighteen samples were taken 10 meters apart seaward of that point until the 19^th sample would have been underwater.. This transect provides a record of the density of vegetation across the marsh for future refence studies. The samples were collected with a post hole digger havin a capacity of 3080 cc, the sample forming a cylinder of 20 cm length and 114 cm diameter.The principal macroscopic invertebrate living in the marshes were the purple-striped reddish shore crab Hemigrapsus oregonensis, and the California horn- snail Cerithidea californica.

Through tide height measurements in five mareográficas stations and using a discharge model, the velocities are obtained, due to astronomical and meteorological effects. With the measurements and averages of salinity considered velocities due to density gradients are obtained, in different places, with which the relative importance of the three currents along the bay is evaluated. It is possible to tell which is the zone with bigger or lesser disperse power using a tracer (rodamina wt), with which the decay in different zones according to time is measured. The result of the dispersion analysis can be used in contamination, in the study of transportation of certain suspense sediments as it is in mariculture. A specific case is the application of this dispersion model in the oyster crop through which an analogy is done between the ink and the larvae. This work consists in the application of the Carter dispersion model (1967) in San Quintín Bay, Baja California, México. This model can be used with any planctonic organism that tolerate the salinity and temperature ranks, that exists in the Bay and its characteristics make it applicable to other estuarine regions of coastal lagoons. The data obtained, the field work techniques and expeditions to measurements correspond to several cruisers done in July 1977, by the Coastal lagoons, by CICESE’s Oceanographic Department.

This project was done with the object to establish scientific basis for the study of the environmental impact that Pesquera Zapata’s activities would produce in San Quintín, B. C. Its main objective is to describe in a coherent way, the characteristics and environmental parameters that are needed in a mathematical modeling of the environmental impact that will be given once this region is industrially developed. In this project, Biology, Geology, Physics, Chemical, Ecological and Fisheries information is given, besides a historical review of the location, who intent to familiarize the reader with the region.

Series of sea level time, current velocity, temperature, salinity, oxygen, inorganic phosphate, chlorophyll a, seston, plenty species of phytoplancton, carbon and organic nitrogen particle and primary productivity were generated, from the mouth of the San Quintin Bay, Baja California, for 18 days during the summer of 1977. It was done to determine some factors that cause variability of these ecological properties, and as a frame for some generalities, about the direction and magnitude of the flows, in the joint between the bay and the coastal shores during the summer season. San Quintin Bay is considered of interest for the development of mariculture activities. The alternation of the surgence events was the main cause for the variability of all the properties, with the exception of temperature. The semi-daily tides were the main cause for the temperature variability. The conservative variables, such as the temperature and salinity have a semi-daily component bigger than the daytime ones. Most of the non conservative variables (chlorophyll a and phosphates concentration, for instance) have daily and semi-daily variability, due to the strong dependency of the biological components variability for the oxygen was intermediate between the conservatives and non conservatives variable relations. The seston variability was mainly due to the turbulence produced by the winds and the tidal currents. The lack of correlation between organic carbon particle and nitrogen, and the wide rank of the relation C:N particle, show than the seston derived from the bay of a very wide variety of organic content represents the majority of the suspended particle material. More than 99% of the suspended particle material is detritus produced, mainly for the degradation of the eelgrass. The upwelling is responsible of the high concentrations of chlorophyll a and inorganic phosphate that are found in the bay.

Only during the second upwelling (the last 7 days of the sampling period) a significant exportation from the bay seem to exist, and it is shown and observed by the media fluctuations of the temperature, oxygen and chlorophyll a. As for the other variables and during some other moments of the sampling period, there were non significant fluctuation flow averages. The fact that there has only been one station in the mouth of the bay makes it difficult to evaluate the flow fluctuation. The diatomea always were the more abundant phytoplanctonic group. The primary productivity was always bigger on the surface, with a media value of 27 mgC/m3/hour during all sampling period. The maximum productivity values on the surface were obtained during the aftermath period to the upwelling appearance (above de 44mgC/m3/hour). An average value of 122 mgC/m3/hour was found in the whole column of water during the 18 days of the sampling period. These values are comparable to the productivity highest found in other upwelling areas. The superficial assimilation rate average was of 6.6 mgC (mgChla/hour) that shows that water is rich in nutrients.

Map for the Lazaro Cardenas San Quintin region’s different aquatic mantles

This document consists of five parts. The first is an introduction of the urban planning at national level, where it gives the preliminary aspects and the legal basis of the urban planning of the country. The second one gives a diagnosis of the San Quintin area, where the description of the natural media characteristics are given such as: orography, hydrographic, geology, land occupancy, socioeconomic aspects, also the urban structure (housing, infrastructure, and services, risks, use of land, administration of the urban development and urban structure). The third part of the document deals with the forecast phase, in this part, based on data and amounts quoted in the diagnosis they try to determine the future development path of the town, that form the urban area San Quintín-Lázaro Cárdenas as of natural tendencies. Problems and limitations they may encounter, for their future urban development, if the given conditions until today, continued. The fourth phase, is the proposition part of the document, and regulations and development strategies, in which an objective image of the population center is established, constitute it. The last part of the document is the annexes, which give complementary information, such as socioeconomic tables, uses definition and graphic annex.

.Superficial sediment samplings were done in 39 stations of the San Quintín Bay. The purpose is to know the concentration of total heavy metals Al, Cd, Cr, Cu, Fe, Mn, Ni and Zn, in three main areas: Bahia Falsa, the main mouth and San Quintín Bay. Concentration of mentioned metals is given. It was found that the accumulation regions were presented in the sedimentary environments of marshes and in the oyster biodeposits. In general, the chemical characteristics of the local sediments showed a high level of Al in the sandy fraction, but in the other metals, the concentrations were between de natural levels. An analysis of the main components was effected, in which the metals were regrouped in three groups and through geographic localization of each it can be deduced potential metal sources to the sediment of the studied area. The important and potential metal sources, are the upwelling, the volcanic complex of San Quintín Bay and the discharge of the San Simón watershed.

By a collaboration agreement, between the California Hunting and Fisheries Department, U.S.A. and the Institute of Oceanographic Research, from the University Autonomous of Baja California, a trace toxic contaminants vigilance program was started, in 1992, using biologic meters (mollusks in the Baja California seashore area). The objective of the project is the investigation of the mercury biologic availability, in the northern coastal waters of Baja California, using for such purpose as an indicator organism the resident mussel Mytilus Californianus. The organisms were collected in eight coastal sites, located from the border México, U.S.A. up to San Quintín Bay, south of the peninsula, (300 kilometers approx.). The results were discussed in relation with the seasonal and geographic contamination variation. Two conduct patterns are observed in the mercury biological availability. The bigger mussel mercury concentrations occurred in relatively isolated sites, of antropogenic sources in the south sector (Ensenada to San Quintin Bay). It suggested that this phenomenon could be associated to strong upwelling in the area.

DDT measurements were done in two different species of oyster crops, in Punta Banda Estuary and in San Quintín Bay. The magnitude of the concentrations found are not dangerous for human use, and both studied areas could be considered with very little contamination.

In this study the concentration and body burden of DDT and metabolites have been determined in the Pacific oyster C.gigas cultivated by the Sociedad Coperativa de Produccion Pesquera Bahía Falsa, Baja California. The relationship between age and DDT concentrations during the culture period is discussed. Evidence is presented which indicates that DDT concentrations increase with age and dry weigth of oysters. Comparing DDT values determined five years ago in cultures oysters C gigas in Bahía Falsa with de present ones, substantial differences are not evident. The DDT values reported here are about five times below those reported in mussels Mytilus sp. of the Southern California coast, USA. The DDT concentrations detected in the oysters are below thetolerance limit established as presenting a hazard for human consumption.

In order to estimate organochlorine contamination of Playa San Ramón and el Playón from the San Quintín region, concentrations of DDT have been determined in the pismo clam Tivella stultorum during February, April, June and Agust of 1983. The results indicate DDT values significantly higher in Playa San Ramon. The concentrations of DDT are about tree orders of magnitude below those which are regarded to present a hazard as human food..

The objective of the project was to inform the possible effects to the marine environment, that the operation of a fish flour factory, with 80-ton/h capacity, would have in San Quintín Bay. Information is given about the factory design characteristics, and it emphasizes that if the factory is built and operated accordingly to the design and considering the water residency time in San Quintín Bay, there won’t be accumulation of contaminants.

In 1991 a study was done to establish the concentrations of chlorine hydrocarbons in seagull eggs, in the west seashore of México-USA (Larus occidentalis). The sampling sites included Coronado Island, Todos Santos Island and San Martín Island, which is located 5 km west of San Quintín Valley. This project provides information of the general contamination pattern of pollutants, by chlorine hydrocarbons, through the use of western seagull eggs as a biologic meter.

Besides, the thickness of the eggshells was measured, to see if the thickness had changed in the past 20 years. The sea gull feed diet components were checked to know if chlorine hydrocarbons could be found in them.

All the leftovers showed low levels of concentration, with the exception of pp’DDE and th BPCs, in some samples. The pp’-DDE, op’-DDt, the a BCH, the HCB and the BPCs were found in sea urchin (Strongylocentrotus purpuratus), the most important catch of the Todos Santos western sea gull. The pp’-DDE was the most abundant component for the complex DDT and its levels of concentration were the highest within the detected residue. However it doesn’t represent a problem for the western sea gull reproduction. On the contrary, the observed reproduction was optimum, at least in Todos Santos Island and San Martín Island, and thickness recuperation in the eggshell was detected.

Berdeja-García, Y. y A.M. Aguirre, 1988. Estudio de evaluación de la calidad de agua y producto en la Bahía de San Quintín, Ensenada, B. C. Zona de producción de moluscos bivalvos. Informe Técnico presentado a la Secretaría de Salud. subsecretaría de Regulación Sanitaria y Desarrollo. Dirección General de Investigación y Desarrollo Tecnológico. 51pp.

Information is given about the San Quintin Bay’s physiographic, hydrologic, historic and social economics characteristics, emphasizing the acuaculture activities that has developed en the Baja California State in the last decade. The mollusk program history, the purposes and objectives. A production census by species in 1987 was included. The bay’s pollutant sources are identified and evaluated, superficial water samplings were done for bacteriologic analysis, the most probable number was determined with this method. The coliform results showed that for some stations, the values exceed the 70 NMP/100ml. In the statistical analysis it is observed that during the sampling days, the 10% of the total samplings do not exceed the 230NMP/100ML. value. However, the hydrodynamic aspects of the study area offer advantageous conditions for the water exchange, this guarantees the elimination of any contaminate event, in very short periods of time.

Information is given about the San Quintin Bay’s physiographic, hydrologic, historic and social economics characteristics, emphasizing the acuaculture activities that has developed en the Baja California State in the last decade. The mollusk program history, the purposes and objectives. A production census by species in 1987 was included. The bay’s pollutant sources are identified and evaluated, superficial water samplings were done for bacteriologic analysis, the most probable number was determined with this method. The coliform results showed that for some stations, the values exceed the 70 NMP/100ml. In the statistical analysis it is observed that during the sampling days, the 10% of the total samplings do not exceed the 230NMP/100ML. value. However, the hydrodynamic aspects of the study area offer advantageous conditions for the water exchange, this guarantees the elimination of any contaminate event, in very short periods of time.

During critical season of environmental pollution bacteriological samplings were made in Willard Bay and Los Angeles Bay, Baja California, in 1985-1987, and in Falsa Bay and Todos Santos Bay, B.C. in 1991-1993. The objetive of this study was to determine the quality of the water for culturing bivalve molluscs. Bacteriological faecal indicators (total coliforms and faecal coliforms) were determined by MPN technique, according to standard methods. Except for summer 1985 in Willard Bay, when a significant amount of organic material was introduced bay fishing boats and winter 1992 in Falsa Bay when there was and important input of bacteria due to rainfall, the bacteriological cuality of the water was acceptablefor culturing bivalve molluscs in the four locations, since the values were below the limit estableshed by legislation.

Comparison of carbon, nitrogen and phosphorus fluxes in mexican coastal lagoons. Compiled and edited by S.V. Smith, S. Ibarra-Obando, P.R. Boundreau and V.F. Camacho-Ibar. This paper gave us calculations to intended to pull the gross and net metabolism of Bahía San Quintín into perspective, in order to illustrate the utility of of direct estimates of gross metabolism for estimating turnover of materials and the utility of direct estimates of net metabolism for estimating primary production-respiration. The bomass is only estimated to the nearest order of magnitude and is intended only as a crude index of material turnover

One hundred and twenty plants species were collected on the dunes along the 1400 Km-long western coast of the peninsula of Baja California, México. At sixteen of the thirty-two sampled locations between Tijuana, B.C. and La Paz, B.C.S., transects were made at right angles to the shore to record cover and zonation of these species. Abronia maritima, was found along the entire coast and it was the major foredune-builder throughout most of its range. The ranges of most of the others species fall into one of the three groups corresponding to regions of inland vegetation and to Köppen climatic types of semi-arid (BS) south to 30°N, arid (BW) in the central part, and aris tropical (BSh) south of 30°N. Within each region the vegetation on dunes inmediately above the beach is more uniform than that on the backdunes, where the shrubby vegetation varies acording to the degree of surface stabilization.

The phosphate and silicate concentration in San Quintin Bay increases, in general, from the mouth to the interiors of the Bay. It reaches very high values of more than 4µ M for phosphate and silicate. Both, phosphate and silicate at the mouth, are higher during summer than winter, because of the upwelling effect. The higher concentration in the interior do not necessarily cause an increase of phytoplankton biomass, because the biomass depend also on the temperature and salinity gradients. During summer we found higher nutrients concentration associated with lower phytoplankton nutrients biomass. The bay is a wter body that produces inorganic nutrients. Its abundant population of marine grasses act as a trap for organic matter, with intense reminerilization occurring at the bottom. This is also deposition mechanism that will cause the Bay to disapper. The phosphate distribution allows us to define the total equivalent nitrogen distribution

Results of the distribution of temperature, salinity, disolved oxygen, concentration ph and alkalinity in San Quintin Bay, Baja California, for winter and Spring, are presented and discussed. Based on the results of a study of the diurnal variation of these parameters at the beginning of spring atemperaturere presented and discussed. Based on the results we conclud that cultering Crassostrea virginica (american oyster) is not adecuate; culturing Cassostrea gigas (japanese oyster) is adecuate, but salinity conditions are better for Ostrea lurida and Ostrea edulis

Approximately 107 species of plants are endemic to Northwestern Baja california; many of these endemic and near-endemic species are dominant in this region; however a number are considered rare on both sides of the border. The differences between coastal sage scrub and maritime succulent scrub communities from those of the Californian Floristic Province north of the border can be demostrated by discussing the vegetation and endemics of a number of important localities, proceeding from the border southward and from coast inland. This paper shows a list of 30 endemic species restricted to Northwestern Baja California.

This book discusses or describes over 550 plants and pictures over 275 of them. Most native trees and larger woody shrubs are included, common widespread, or prominent woody shrubs, vines, herbaceous, endemic plants are also described.

Four diurnal variations were observed, in the mouth of San Quintín Bay and two in the Estero de Punta Banda. These observations were taken during Autum and Winter. Respect to the internal conditions of the systems, it has been found that heating due to solar radiation and evaporation produced principally by winds regulate the vertical gradient of temperature and salinity. These processes produce inversions in San Quintín Bay althogth this can be easily destroyed due to the small superficial and deep values as weell as the shallow water layer and the currents and turbulence that are present.

This work was done with the purpose of backing de mariculture development in Baja California, a methodology was tried to develop to estimate the available food for species in crops in coastal lagoons. Some preliminary reports of the change in the fitoplancton’s biomes were reported, represented by the variation in the chlorophyll a concentration.

This work qualitatively evaluated the circulation due to density gradients. This circulation usually is several magnitude orders lower than the induced circulation by the tides, and it is not directly observed through the horizontal currentimeters , therefore it is then needed to determine and analyze temperature, salinity and density distributions. Knowing the density structure and its possible induced currents, the system’s vertical homogeneity and heterogeneity could be determined, being useful for its applications in mariculture larvae dispersion phenomenon, contaminant evacuation, etc. Vertical temperature profiles, salinity and sigma-t were performed, in the two branches of the bay, besides longitudinal curves of temperature, salinity and sigma-t were done from the mouth to the heads, in both bays. The results report that the temperature variation is the most important factor in the distribution by density. This implies that the process of heating is dominant over the evaporation. In the majority of the cases, the waters in the bay are less dense close to the heads than in the mouth, tending to flow outside waters for the surface, while the sea dense water will sink flowing towards the head by the bottom. This kind of circulation, is in several orders of lesser magnitude and it is superimposed to the circulation by astronomic tide, that is predominant and in one sense of bottom surface.

The seasonal variation is presented of the organic material in sediments and biodeposits in the San Quintín Bay, where, through the sediment traps, the deposit rate was calculated for a yearly cycle and the content of total organic material, was determined in the collected sediment. It was also calculated the oysters Crassostrea gigas excretion rate, and it was found a seasonal variation in the sedimentation rate, with values of 13.7 Kg/m2/month, in summer and minimum in winter with 5.8kg/m2/month, attributed probably to waste organic products resulting from the oyster crops. The average value of organic material was of an 8%. The biodeposition rate was calculated in an average of 0.5% (dry weight). According to the type of crop that is done en this bay, it was found that the average excretion rate for the oysters cultivated is an average size of .5g oyster/day. Estimation is made of the amount of biodeposits that could provide the oyster crops to the coastal lagoon and their effects on the zone are being discussed. The filter-feeding organism, when they eat the food in the bay, they accelerate the deposition rate, because through their digestion, form bigger particles that for their size, fall faster than those without crop conditions would.

Phytoplankton gross taxonomic groups (diatoms, dinoflagellates and microflagellates) abundance time series, generated at the mouth of san Quintín Bay and Estero de Punta banda, are presented and discussed. Diatoms were the most abundant group at San Quintín, while microflagellates had the lowest concentations.. The total phytoplankton abundance tiem series variance spectrum of san Quintín does not show a clear dominance of variance at characteristic frequencies of phenomena such as tides, solar radiation cycles, upwelling events, etc. This is due to the patchy distribution of hytoplankton. At San Quintín mouth, diatoms were the most abundant; but at hthe heads the most abundant were dinoflagellates.

The present survey of Bahia de San Quintin in Baja California fulfills two pimary purposes: a search for basic information on an unpolluted enclosure as near southern California as posible, and the initiation of comparative investigations. This report forms an introduction to a series of articles to be published on the geology, hidrography and benthic life of the bay, an includes those descriptive features not being treated elsewhere. This study report 36 species of algae (Twenty-three red algae, nine green algae, four brown algae and one blue-green algae). An a 11 species of saltmarsh plants.

From June to december 1982, monthly samples were taken to determine the biomass of drift and epiphytic macroalgae in a Zostera marina meadow, in bahía Falsa, San Quintín. Three transects were determined: -0.95 m (I),-0.80 m (II), y -0.65 m, (III) in relation to mean sea level, and 5 replicates of 20x20 cm in each transect were collected. Simultaneously, samples for taxonomic identification were collected and preserved. During the autumn a notable increase in biomas was observed attributed to green algae. Although the biomass expressed in g dry weight/ m² represents an intermediate value compared to those reported in the literature, when expressed as a percentage of total aereal biomass of Z.marina in San Quintín, it represents an averange of 55% of it. On the other hand, no significative difference among transects was observed.

The taxonomic study showed a total of ten genera and eleven species, of which five were green algae, one brown algae and four red algae. This is the first report for this region of: Enteromorpha clathrata, Giffordia sandriana y Cryptopleura spatulata, which raises the total number to 30 genera, 39 species and one variety. The majority of macroalgae found were forming great masses on the Z.marina meadow and sediment.

This study attempted to survey one of the principal benthic marine plant communities od California is that dominated by the largest known marine algae Macrocystis pyrifera , through s portion of its range, observation about the floristic composition of this community and to distinguish, record and characterize its prominent plant. The major emphasis in this work has been placed on the illustrations of the prevalent plants and of a key to aid in their identification.

From July to December of 1982 monthly samples were taken in Bahia Falsa, San Quintin, in order to determine the composition of the epiphytic diatom flora living upon Zostera marina. The taxonomic analysis yielded a total of 235 taxa in both species and varieties. The list and references of the identified taxa is presented, as well as an appendix with photographs of 135 specimens.

A 56 amphipoda species list, nine of them were not collected in grab samples. Discuss zoogeography of the species, and makes a comparison with Newport bay amphipods, and also compare San Quintín amphipod with the open sea. Shows a table with the habitat origins of the amphipods in Bahía San Quintín and a relationship of abundant amphipods to percent sand of substrate.

During the second half of 1982, monthly samples of Zostera marina where taken in Bahia Falsa, San Quintín. The objetive was to analyze the structure of the associations of epiphytic diatoms. The most important species according to their Biological index value BIV were, Navicula parva, Cocconeis scutellum, Cocconeis seutellum var. parva, Cocconeis dirupta y Nitzschia frustulum var. perminuta. The species with the wider niche breadth was Cocconeis placentula var. euglypta.

Monthly surface sediment samples were taken from a locality of Bahia San Quintin, from February through April 1982, to study the specific composition of benthic diatoms, content of chlorophyll a and its phaeopigments. Also, temperature was measured and analysis were done for organic matter content. 75 taxa were recognized (genera, species and varieties). Pennate diatoms were 88%. The main associations were: Navicula cancellata - Amphora coffaeiformis; y Amphora coffaeiformis - Cocconeis scutellum. Sediment chlorophyll a content variation had no relation with abundance of benthic diatoms. This abundance did not change significantly during the sampling period. Diversity and equitability indices showed very low dominance.

This study describes a relativily pristine salt marsh and ecotones that could serve as a comparison for understanding disturbed West coast marshes. The salt marsh and terrestial transitional vegetation of Bahía de San Quintín is composed of a low numers of species with only a few dominants, and it is similar to southern California marshes. The vascular plants present in the salt marshes of Bahía de San Quintín were identified according to Munz (1959) ans Shreve and Wigging (1964) Voucher specimens are on file in the california State University, Los Angeles (CSULA) herbarium. Seventeen saltmarsh specieswere found in Bahía de San Quintín, five represent tropical floristic elements. The marsh flora is composed of only 17 phanerogams species. The transitional flora is representes by 33 species from 28 genera and 19 families. Of these species, 12 are characteristically found in salt marsh, and 21 are normallly associated with desert and coastal uplands.

Se realizó un estudio fitosociológico de las comunidades de plantas vasculares existentes en los saladares y manglares de la península de Baja California. La zona de estudio se extendio desde el estuario del Río Tijuana en el condado de San Diego, California, E.U.A. hasta el Llano de Magdalena en Baja California Sur, México. Se aplico la metodología fitosociológica sigmatística. En cada una de las localidades estudiadas se analizarón diversos parámetros: zonación, composición florística, medidas microtopográficas y análisis fitosociológico. Se reconocio un total de 16 asociaciones, de las cuales nueve de estas asociaciones se pueden encontrar en la Bahía de San Quintín. Para cada una de las cuales se comentan diversos aspectos dinámicos, estructurales, ecológicos, biogeográficos, florísticos y sintaxonómicos. Se discute la zonación existente en los saladares y manglares estudiados.

Field work was conducted between the international border and El Rosario. A 40 specimens were collected from 19 localities between 16 January and 27 February and again in December 1991. The gnatcatchers were collected with a mist net. Captured birds were sacrified or released. The California Gnatcatchers of Northwestern Baja California represent a previously undescribed subspecies, hitherto included under Polioptila californica californica, for which we propose the name Polioptila californica atwoodi. Ranging from about Ensenada and Valle de las Palmas south to El Rosario, it differs from nominate californica in the paler, grayer (less brownish) back, flanks, and crissum of females. Males differ in only rarely having faint brown tinge to the back frequent in nominate californica . From Polioptila californica pontilis, the subspecies of central Baja California, both sexes of atwoodi differ in their darker upperparts and gray, not whitish, underparts.

Between January to December, 1985, samples were collected in seven representative tomato farms (El Seco, El Dátil, El Milagro, Valladolid Oeste y Sureste, Los Canelos y Los Pinos) of Valle de San Quintín. Areas were located in a map (scale 1:100,000). Each ranch were visited month to month during a year. For each location five samples were taken for each diferent species, the samples were identified and herborized ( each mounted plant show roots, stem, leaf, flowers and seeds) then registed and deposited in the BCMEX herbarium in the Facultad de Ciencias-U.A.B.C. in Ensenada. This document report a total of 48 species in 16 families identified, all of them phanerogams or vascular plants. The greatest diverity of species occurred in the family Graminae (144 species) and compositae (7 species). The largest number of species was found in the farms El Seco, Los Canelos and Los Pinos. All the species found are introduced.

Fifteen southern California saltmarshes were censused during the period from March 26 to June 13, 1980. Surveys were done by listening to spontaneous vocalizations of the rails at dusk and plotting locations of calling pairs on a map. This study resulted in an estimate of 203 pairs of nesting Light-footed clapper rail. An examination of the status of the Light-footed clapper rail in Baja California, México was begun during spring 1981. The authors censused no more than one-forth of the suitable habitat at Estero de Punta Banda, and heard 68 pairs Clapper rail, and less than one-fifth of the saltmarsh at Bahía de San Quintín and heard 107 pairs. Projection of these partial counts yields a rough minimum estimate of 800 pairs of Clapper rails residing in the two saltmarshes.

In this study explores all accessibles sites where Least terns might nest along the coast between the U.S. - Mexican border and Laguna Ojo de Liebre. Also checking two others subspecies that are considered endangered in California the Light-footed Clapper Rail and Belding´s Savannah Sparrow.

The breeding population of Snowy Plovers (Charadrius alexandrinus) was surveyed along the Pacific coast of Baja California from 1991 to 1992. All accesible potential breeding sites from Tijuana to Cabo San Lucas were covered. The 1344 adult Snowy Plovers counted were mostly distributed (88% of the total Baja California population) at the four main coastal wetland complexes of the peninsula: Bahía San Quintín, Laguna Ojo de Liebre-Guerrero Negro, Laguna San Ignacio and Bahia Magdalena. The habitats harboring the largest numbers of birds were barrier beaches and salt flat. It si concluded that the number of Snowy Plovers on the peninsula of Baja California likely represents at least 50% of the total population nesting on the west coast of North America.

A discover of two or three calling Black Rails (Laterallus jamaicensis) at Bahía San Quintín on February 19, 1991. In the southeastern portion of the estuary in the pickleweed (Salicornia spp.) marsh near to house. The California Black Rail (Laterallus jamaicensis coturniculus) is known only from California, Arizona and northwestern Baja California. The California Black Rail is listed as threatened by the State of California, Endangered by the State of Arizona, and a Category 1 Candidate for threatened or endangered status by the U.S. federal government. In Baja California there have been no other Black Rail reports since early in the century.

This paper report a survey of the breeding birds of Laguna Figueroa and La Pinta pond, Baja California. A total of 7 species were counted six of them were reported in both sites.

During autum of 1990 begins a study betwwen Mexico-U.S.A. the main porpouse were reserch about the ecology of the Brant. The objetives were migration and distributions of the Brant in Mexico, abundance and distribution in each habitat using for the Brants, and human and natural disturbances over the Brants.

Point Reyes Bird Observatory organized a broad survey to quantify the importance of specific wetlands to wintering and migratory shorebirds in western North America. In wetlands along the west coast of Baja California, México, 354,905 shorebirds were estimated present in winter based on ground and air surveys between January 1991 and January 1994. The Laguna Ojo de Liebre/Guerrero Negro wetland complex held many more wintering shorebirds than any other Baja California site.

Although Baja California has not experienced loss of wetlands comparable in magnitude to that in California, some habitat changes have provoked changes in the abundance and distribution of wetland avifauna. This paper document ocurrence and changes in avian composition a long the wetland complexes in Baja California. Threats to the wetlands are primarily from resort and industrial developments being planned by international companies. Conservation of these vital avian habitats is a matter of concern to all ornithologist.

This is a review of the distribution of vertebrates in the Mediterranean Region of Baja California, Mexico. Based on distributional limits of vertebrate species the author establishes the southermost limit of the Mediterranean Region in Baja California. It discusses conservation problems of the fauna, and especially for those endemic species.

Among the mollusks taken during a ecological survey of Bahía de San Quintín, Baja California, noticed a single specimen of an unusual bivalve, the most closely related genus seems to be Orobitella, but so many points of difference was evident that the proposal for a new subgenus seems advisable. A complete list of 34 species of mollusca taken during the ecological survey is given. Mollusk are poorly represented in this bay.

Desde Abril de 1992 hasta Septiembre de 1995, se efectuaron un total de 352 recolectas en la Bahía de de San Quintín y 330 para la costa, utilizando en ambas las siguientes artes de pesca: Red Trineo, red de arrastre, chinchorro playero, red agallera y anzuelo.cinco En la lista de especies. La metodología para la recolecta fue siguiendo los lineamientos del programa BENES (Bay, Estuarine, and Nearshore Ecosystem Studies) del Departamento de Caza y Pesca de California, el muestreo fue dirigido a toda la comunidad desde juveniles de uno o más años, hasta los peces mas grandes. Se utilizarón dos embarcaciones, un bote de 8 m de eslora con motor estacionario (350 HP) y una lancha pequeña de fibra de vidrio de 4 m con motor fuera de borda (25 HP) para los sitios cercanos a la playa. En la Bahía de San Quintín se registró un número de 64 especies de peces , y de 67 especies de peces en la costa . Se encontro ademas 48 especies comunes al sistema Bahia de San Quintin - Costa de San Quintin. La especie mas abundantes en la Bahía de San Quintín fue el pez pipa Syngnathus leptorhynchus (23.7%), seguido de la perca brillante Cymatogaster aggregata (14.5%) y el aterínido Atherinops affinis (10.9%). El pez endémico de la Bahía paraclinus walkeri fué colectado en un bajo número. Para la costa de San Quintín la berrugata Genyonemus lineatus fue la mas abundante (20.1%), seguido de la anchoveta norteña Engraulix mordax (12.6%).

A check-list of fish species froom Bahía de San Quintín, Baja California, México, and its adjacent shallow coast is presented. A toal of 682 samplings were conducted between 1993 and 1995, with monthly efforts during 1994. A total of 90 species were identified, 9 of wich were elasmobranch, from 41 families. Sixty-nine species were collected from Bahía San Quintín and 71 from the coast; only 50 species were common to both environments. The best represented family was Embiotocidae, with 1'0 species, and the genus Sebastes showed the greatest number of species, with 5. The ichthyofauna of Bahía San Quintín has never been studied in a systematic and integral manner, until now.

An ammocoete of the Pacific lamprey Lampetra tridentata was collected on February 19, 1995 in the lowwer Río Santo Domingo, Baja California, México. Approximately 600m above its mouth at Bahía San Ramón, and represent the southernmost freshwater record in western North america.

Quantitative samples were taken using a Hayward bucket in 95 stations, in April 1960. Samples were washed through a screen with 32 openings to the inch (0.5 mm). The material retained on the screen was preserved in formaldehyde and sorted into groups. Later the polychaetes were separated. The faunal affinities of San Quintín bay were clearly related to southern California. All species but Scoloplos ohlini have been reported previously from southern California waters and 30 (60%) of these have been encontered previously in bays and harbors. One new specie Megalomma pigmentum, was found widely distributed in San Quintín. Present a list of 48 species known from Bahía San Quintín. Also discuss the relationship of polychaetes to sediments, the ocurrence of a species on a particular substrate type is given in percentage units. Six species of polychaetes constitute the dominant bay species on the basis of number of specimens.These are, in decreasing order of importance, Prionospio mamgreni, Exogone verugera, Cossura candida, Capitia ambiseta, Scoloplos acmeceps and Fabricia limnicola.

The collections were obtained from grab samples and from formalin sea water washings of rocks and algae around the bay. A total of 87 lots of specimens resulted. There was a noticeable lack of parasitic Bopyridae, but the collections showed a reasonably diverified isopod fauna representing fifteen species from fifteen genera and eleven families. Over 26% of the species appeared to be new to science and four of these are described herein. Types were deposited in the U.S. National Museum.

Parahemiurus noblei n. sp. (Trematoda: Hemiuridae) was described from of the stomach of the Pacific sardine Sardinops caerulea. Observations on living and mounted specimens of Tubulovesicula lindbergi (Trematoda: Hemiuridae) was discussed. A new locality and three new hosts for the latter species were recorded. The material for this study was obteined in November 1960 from fishes collected at Bahía de San Quintín, Baja California, México. A total of 83 fishes of sixteen different species were autopsied and their stomach checked for a digenetic trematodes. The worms were fixed with or without slight cover-glass pressure in warm Gilson´s fluid and stored in 70 per cent ethyl alcohol. All of the worms were prepared in the usual manner and were stained with Kornhauser´s Haematoxylin. Drawing were made with the aid of a camera Lucida and an upright microprojector; measurements were in millimeters.

Of a total of 19 epifaunales species collected at the eel grass beds in front of the field El Chute, in the San Quintín Bay, B. C. the crustacean anfipodos of the Gammaridea family were dominant. Samplings were analyzed on April, July, August, September, November and December in 1993. A taxonomic description is presented, keys used for their identification, ecological distribution, besides original figures of each specie. Personal observations were included and some others already published by experts on the field with the purpose of making easier the taxonomic identification.

Eight species from five families of polychaetes previously not reported for the area were found during three benthic samplings surveys in Bahía San Quintín in July and september 1981 and February 1982. The species include one orbiniid: Phylo felix, one paranoid: Aricidea suecica, three spionids: Prionospio heterobranchia sub. newportensis, Prionospio cirrifera and Pseudopolydora kempi, one megalonid. Megelona pitelkai and two capitellids: Notomastus (Clistomastus) tenuis and Mediostamus californiensis. For these species, their distribution is extended far southward to Bahía de San Quintín. A discussion about their biological meaning in the bay and some aspects of their biogeography is presented.

Samples were collected at 11 stations in July, September and December 1981, and February and May 1982. Thirty-nine species in 21 families of polychaetes were identified. The abundance increased in spring because of reproduction and recruitment. Five were the dominant species Exogone occidentalis, Pseudipolydora kempi, Scoloplos acmeceps, Prionospio heterobranchia and Neanthes arenaceodentata,The benthic community in Baía de San Quintín was found to be at or near equilibrium which may be the result of a relatively high resilience to disturbance. A qualitative assessment of the posible impact of domestic sewage on the infauna and an outline for the ecological mangement of the bay are presented.

The marine littoral tubificid Tectidrilus diversus Erséus, 1982 is reported for the first time in México, in Bahía San Quintín, Baja California. The new record is a range extension of the species, which has been previously known on the Brittish Columbia, Washington and California coasts.

Polychaete annelids collected in San Quintín Bay were analyzed. Thirty-nine stations were sampled with a geological type coree in December 1992, in depths of 2 to 6 m. A total off 677 polychaetes (17 families, 28 genera and 32 species) were recognized. Sixteen species and four gegera were recorded for the first time in the area. The best represented families were: Syllidae (124 species), Lumbrineridae (100), Flabelligeridae (75), Nereididae (74), Cossuridae (73), Spionidae (58), Capitellidae (49), Cirratulidae (44) and Maldanidae (29). The most abundant species were Scoletoma tetraura, Brada villosa, Cossura candida, Neanthes acuminata, Pionosyllis sp., Notostamus sp., Exogone lourei, Pronospio heterobranchia, Chaetozone sp. and Exogone dispar. The eastern arm of San Quintín Bay presented slightly higher values of species richness and polychaete abundances. Of the 28 families previously reported for this lagoon, 17 were found and the families Trichobanchidae and Apistobranchidae are added. To date, there are 81 polychaete species, belonging to 30 families, reported from San Quintín Bay.

Museo de Zoología de Vertebrados. Berkeley, CA. 94720. Dr. James L. Patton. Museo Nacional de Historia Natural. Washington, D. C. 20560. Fisher, R. D. Especímenes.

This list reports the presence of 17 mammalian species, two of which have a special status. This lists are part of a document "Bahía de San Quintín UN diagnóstico para su protección", that was presented before the then SEDUE, in 1992. This proposal includes in the general information, the surface that propose to protect, and the information of the physical and biological characteristics (charts are included about the physical characteristics and species lists), cultural-historic characteristics, social-economic aspects, legal and research aspects.

A sighting is reported of a gray whale feeding itself in the southern part of the San Quintín Bay, Baja California, where it hasn’t been reports before. More recent information tells of some young animals were doing it inside the San Quintin Bay and some adults in de seashore of El Rosario, Baja California. El Ampelisca compressa anfipodo is abundant in the San Quintin Bay. Its availability is comparable with the A. macrocephala, principal food of the Arctic gray whale. In later sightings (June 12-13 and July 5-6) no whale was seen, therefore it is not possible to conclude if the registered activity represents late migrants in emergency feeding or animals spending the summer in the Californian coasts.

The known geographic distribution of D. gravipes extends southward from near San Telmo to near El Rosario in Baja California, Mexico; an area extending about 20 km eastward from the Pacific Ocean. The southern populations of D. gravipes near El Rosario may be geographically isolated from the northern populations. The elevational distribution is from sea level to about 30m. No fossils of D. gravipes are known. Dipodomys gravipes largely has been eliminated from most of its native range during the paste decade by extensive cultivation. The species apparently possesses a high affinity for flat land and a lack of tolerance to cultivation.

Departamento de Herpetología. Académia de Ciencias de California. Golden Gate Park, San Francisco, CA. 94118. Vinduon, J. U.

Museo de Zoología de Vertebrados. Berkeley,CA. 94720. Good, D

Departamento de Ecología de Campo y Biologia Evolutiva. Universidad de California. Irvine. CA. 92717 Griftis, R. Observaciones de Campo

The lists of amphibian and reptile species were generated from the scientific collections of the Natural History Museum in San Diego, from the California Academy of Sciences in San Francisco, from the Vertebrate Zoology Museum in Berkeley and of Griftis personal observations. This lists form part of the document "Bahía de San Quintín UN diagnóstico para su protección" , that was presented before the then SEDUE,1992.

Waterbirds and raptors were recorded in this paper. Between November 1^st 1974 to April 3, 1975. A total 128 days of field observations plus additionals sightings were made in January 1972, 1976 and November 1979. Birds was conted from a 25 km road that begins at the motels and makes a complete loop of the central peninsula, most observations were made from 12 points along the route, the observations takes 2 to 4 hours. Twelve species was recorded ten waterbirds and two raptors. Some additions to the avifaunal informations on this area previously published in Grinell (1928) and Friedmannn et al. (1950).

A 93 water and terrestial bird list, sites observed were around the bay, Old Mill area, Punta Azufre and along de road between Ensenada- Camalú- San Quintín.

This is an annotated list of known avifaunal records of Baja California, México with an introductory section an habitat and conservation, a bibliography of Baja California ornithology, and an appendix of place names, a checklist, and an additional reference section. It summarizes current distributional knowledge on Baja California avifauna (and the nearby Gulf of California) and provides future workers a baseline against which future expected changes in avian habitat and bird distribution can be compare.

Even after the contributions of Wilbur (1987) and several recent reports in Western Birds, the distribution of many birds in Baja California remain poorly known. Observations report in this paper were made by the authors separately or together between 1975 and June 1994. But this paper only include data for northwestern Baja California, that is, between the international border and Río de El Rosario and west of the summits of the Sierras Juárez and San Pedro Mártir. Almost all the records are based on sight identifications only, owing to the difficulty, even for Mexican citizen, in complying with current collecting regulations in México. A total of 44 birds were sighted in 42 sites visited.

Present a listed for all previous records of Black Rails (Laterallus jamaicensis): specimen taken on the San Simón River at Bahía de San Quintín. Two specimens taken at San Telmo, specimen taken from a "tule swamp" at San Ramón, at least one heard at Sangre de Cristo. It is hoped that a population is still resident in the extensive estuary at San Quintín.

Este estudio fue elaborado con el fin de conocer los posibles efectos al ambiente marino que tendría la operación de una planta de harina de pescado con capacidad de 80 ton/h en Bahía de San Quintín. Se da información de las características de diseno de la planta y se hace enfasis en que si la planta es construida y operada de acuerdo al diseno y considerando el tiempo de residencia del agua en la Bahía, no se presentará la acumulación de contaminantes.

The objetive of this paper is to summarize, mainly through a review of the literature, beach vegetation and its phytogeography along the Pacific Coast of North America between Point Barrow, Alaska (approximately 71°N),and Cabo San Lucas, at the southern tip of Baja california (approximately 23°S). The survey of beach vegetation does not include species of adjacent habitats such as dunes, ocean-facing cliffs, saltmarshes, shingle beaches and the intertidal unless those species are also characteristic of beach vegetation. Most of the information summarized in this section comes from floras. Show in a table a list of 46 species with some subspecies, showing latitudinal ranges and distribution patterns for the characteristic beach species of the North American Pacific Coast.

This paper is a list of the species of vascular plants collected or observed in and about Bahía de San Quintín in the marine meadows, salt marshes, dunes, coastal flats, and lava and pumice of the volcanos. The lists is bases primarily on collections made by R.F. Thorne and associates from Rancho Santa Ana Botanic Garden on various trips in 1983 to 1987. Additional species are included from collections made by others, especially by Reid V. Moran, deposited at RSA, SD and DS. The Thorne et. al specimens are mostly deposited at RSA, SD, MEXU, and BCMEX. This list contain a 45 families with 224 species, 27 of those species belived to be introduced in the area.

This paper describes location and main features of the larger coastal wetlands of Baja California state, including Estero de Punta Banda. It summarizes each wetland regarding its current status, ecological, scientific and recreational importance, threats to the habitats and their consequences. It mentions in what lagoons tourism activities can be carried out without diminishing the biological diversity, fishing potential and job source for local people of the wetlands. The paper also analizes the existing legal mechanisms and those to be established in order to achieve a sound management of the natural resources found in these wetlands.

En este trabajo se caracterizó la calidad sanitaria del agua de mar y ostión cultivado, así como la distribución y abundancia de bacterias reductoras de sulfato en sedimentos superficiales de Bahía Falsa, como una evidencia de posible impacto en la zona, por la presencia del ostricultivo. Además se cuantificaron las bacterias de tipo Thiobacillus thiopparus en sedimentos superficiales de la zona.

This work was done as an answer to the authors anxiety due to the worry for the construction of the tourist developments that are planned in the San Quintín Bay area. It mentioned the biologic importance of the area (flora and fauna), and also of the sustainable use and development of the San Quintín Bay, its history cultural importance and through field work an inventory of flora and fauna was made. It gives a technical opinion and explains that, the San Quintín bay gathers the ecological and historical conditions that make it unique in México, in the whole mediterranean region and in the world.