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Temperature is perhaps the most important seawater property. It is a measure of the energy content in the ocean and it affects the metabolic rates, distribution, and abundance of species that are important from the economic and ecological points of view. Satellite-derived oceanographic data have been widely used to assess spatiotemporal variations of sea surface temperature on broad scales; satellites, however, are unable to reach subsurface levels, and obtaining reliable subsurface water temperature data is achieved by either numerical modeling or direct observations, the latter representing a very high-cost alternative. In this paper, a method for modeling temperature profiles is presented. A generalized additive mixed model (GAMM) with a gamma error distribution and an inverse link function was used to model shallow (<200 m) temperature profiles in the Pacific Ocean off northwestern Mexico. The dataset included 656 profiles that were linearly interpolated at depth, which resulted in 127,595 observations. The database covered an area from 18.5° to 25.8°N and from -114.5° to -105.9°W in a time span from June 2007 to November 2016. The model included temperature as response variable; depth, surface dynamic topography, wind stress curl, latitude, longitude, and the Oceanic Niño Index as covariates; and month as random effect. The final model explained 86% of the total deviance of the dataset used to fit the GAMM. Although important deviations between the observations and the predictions of the model were observed, the results of the validation process and of predictions made on an independent dataset (correlation of observed vs. predicted temperature, -0.93; root-mean-square error, -1.5 °C) were comparable to the results obtained with more complex modeling techniques, suggesting that this statistical approach is a valuable tool for modeling oceanographic data. [ABSTRACT FROM AUTHOR]

A literature review is presented about the returning migrant students in the educational system in Mexico, which included both research papers and other types of academic texts, available from 2006 to 2018, and around this population. The revision allowed to identify the research methods and the thematic issues: a typology of these students based in variables such as age, nationality and migration status, the conditions upon the access to and the needs that arise during their permanence in the educational context. Also an educational profile emerged, based on information about their psychological traits, their previous linguistic and schooling experiences, as well as aspects related with the school coexistence and the social integration. Although the existent research is useful to know their characteristics and needs upon the return, studies that inquire aspects such as the relationship bilingualism-academic development, in the different educational levels, are still scarce and thus necessary. [ABSTRACT FROM AUTHOR]

A succession of interannual warm events occurred in the Pacific during the 2013-2016 period, when positive thermal anomalies were detected. A broad region with abnormally warm waters in the northeastern Pacific Ocean was observed in 2013, which by 2015 had reached waters off Baja California (Mexico). In addition to the ongoing warming effect, early evidence of an El Niño event was detected in 2015. This paper analyzes hydrographic data measured at Todos Santos Bay and environs, as well as satellite-derived sea-level data, to characterize changes in the hydrographic conditions during the 2013-2016 period. The highest positive temperature anomalies (~5 °C) were observed in September 2015, with a steep decline to neutral conditions in spring 2016. Records for the bay showed slight variations in hydrographic conditions during spring, highlighting the importance of local over remote forcings during this time of year. In autumn, by contrast, interannual signals prevailed over local processes. Satellite-derived sea-level data revealed an alongshore propagation of remote signals, identified as shallow coastal poleward flows. [ABSTRACT FROM AUTHOR]

The biodiversity and abundance of commercially important biotic resources on the west coast of Campeche (Mexico) is recognized. The main extraction activity is seabob shrimp fishing. This paper aims to analyze and discuss changes in the abundance of the fish community in two annual cycles by statistical analysis. Between February 2003 and January 2004 (cycle 1) and between February 2006 and January 2007 (cycle 2), 37 sites were visited monthly. Physical and chemical parameters were registered and nekton samples were collected by a trawl net. In cycle 1, 49,177 individuals (631.62 kg total weight) were caught and the fish community was represented by 94 species. In cycle 2, 26,386 individuals (407.07 kg total weight) and 94 species were caught. At spatial scale, the fish community abundance values were 0.01-0.23 ind m-2, 0.08-3.02 g m-2, and 7.12-45.45 g ind-1 in cycle 1, and 0.007-0.11 ind m-2, 0.13-1.71 g m-2, and 5.61-15.64 g ind-1 in cycle 2. Highest abundance was recorded during the dry season in cycle 1, but during the rainy season in cycle 2. There were no significant differences in temperature and salinity between the two cycles, but an analysis of variance revealed significant differences between seasons. Significant differences were founded when the matrix of number of individuals per species and month of both cycles was analyzed by multidimensional scaling. [ABSTRACT FROM AUTHOR]

Recent studies performed off the Pacific coast of Mexico have shown a large number of reefs or coral patches in the region, but information is still lacking for some areas. One of these is the Marías Archipelago (21°N), composed of four islands: María Madre, María Magdalena, María Cleofas and San Juanito. The objective of this paper was to make a general evaluation of the status of the corales in the archipelago by revising the systematic list of species and analyzing the community structure and biogeographic patterns of the fauna. Twenty-one locations at María Madre Island and two at San Juanito Island were visited in August 1997, and at each we conducted a video transect (150 m long) to describe zonation and a line transect (20 m long) for quantitative analyses. This information was complemented with literature reviews and data from specimens deposited in museums in Mexico and the United States. After obtaining the systematic list of corals from the islands, we compared the level of similarity of the fauna with that from five nearby regions (including the Revillagigedo Islands and the mainland from 23°N to 18°N), and ordination analyses were run. In the field we observed 13 species of stony corals (including eight new records), but did not find Porites baueri, a nominally endemic species from the Marías Islands. The museum revisions produced two new records. Thus, analyzing the full data set, 20 species are considered residents of the study area. There were no constructional reefs in the archipelago, but coral abundance was high, especially at María Madre Island. The communities showed a clear zonation, with Pocillopora in shallow water and Porites, Pavona and Psammocora in deeper localities. Finally, the biogeographic analysis indicated that the mouth of the Gulf of California represents a key area for species immigration from the western Pacific, and that the Marías Islands seem to act as a nodal point for coral dispersal to the north. [ABSTRACT FROM AUTHOR]

This paper presents a complete list of hermatypic coral species, analyzes the biodiversity levels and describes the biogeographic patterns of the group in the Mexican Pacific. The coral fauna of the MexicanPacific consists of 23 species, which makes this region one of the highest in terms of specific richness within the tropical eastern Pacific. In general, the species are grouped in faunistic units that correspond to the traditional zoogeographic provinces recognized in the region. There is no evidence of effective biogeographic barriers throughout the Mexican Pacific region. Local extinction events, likely caused by the narrow distribution of some species, and perhaps due to the type and frequency of transpacific colonizations, modify the normalprocesses of community succession, causing the Mexican Pacific to bea highly dynamic zone in terms of its coral fauna. [ABSTRACT FROM AUTHOR]

The longline is the most common fishing gear used to catch pelagic fish species. It consists of a principal line or mother line from which secondary lines with hooks hang. This fishing gear has demonstratedits efficiency to catch tuna, shark and billfish. The relative specific selectivity, according to some authors, seems to be influenced byfactors like fishing strategy, horizontal and vertical species distribution, and the kind and size of bait. In this paper, a practical method to estimate hook operating depth is proposed, taking into consideration the catenary line formed by the mother line in each section. This estimate was validated with data obtained by means of a CTD meter placed at the same depth as the hooks during the longline operation. Moreover, an analysis of the species composition of the catch at each hook depth was performed. The results indicate that there is a difference of more than 30 m between operating depths in each section. Likewise, significant differences (at level a = 0.05) among catches ateach operating level were observed. [ABSTRACT FROM AUTHOR]

The relationship between the directional spectrum of sea surface waves and the optical or digital diffraction pattern is well established. Barber (1954) proved that the wave direction can be estimated from the diffraction pattern of a photographic image. This work presents the analysis of aerial sea surface images. The diffraction pattern or power spectrum of each image was obtained to determine the directional spectrum. The technique applied to the sea surface images obtained 12 May, 1993 showed that the waves presented a predominant direction to 65 deg.N and an origin in the 250 deg.SW range. The 200 to 12 m wavelengths were the most frequently found. The implementation and design of the photographic system is described in this paper. We discuss its applicability and limitations, as well as the potential this method has in oceanography. [ABSTRACT FROM AUTHOR]

Off the Mexican Pacific coast. high catch rates are found for striped marlin, sailfish and sword fish. and to a lesser extent for blue marlin and black marlin. making this area an important fishing ground for commercial and sport-fishing fisheries. This paper focuses on the development of the billfish fisheries and their management in the Pacific waters of Mexico. Three periods are described: (1) 1900--1959, (2) 1960--1989 and (3) 1990 to the present. During the period of 1900 to 1959. sport fishing began to develop, resulting in important tourist resorts. A system of fishing permits for this incipient fishery went into force. Also during this period, Mexico established a territorial sea jurisdiction of 9 nautical miles. From 1960 to 1989, commercial fishing for billfish began in Mexico. with the arrival of the Japanese tuna longline fishery, where billfishes were taken as by-catch. Then, with the establishment of the 200-nautical-mile Exclusive Economic Zone (EEZ), Mexico developed its own longline fishery at the beginning of 1980. Because of the fishing interactions between the sport and commercial fisheries, efforts to manage both fisheries were undertaken. At the beginning of the third period (1990 to the present), the commercial fishing for marlin and sailfish in Mexico was prohibitedand only commercial fishing for swordfish is allowed today. Recently, a plan for the development of the sport fishery was published, and regulations on bag limits and fishing gear were established. Althoughbillfish are highly migratory species, Mexico asserted its right to manage this species unilaterally in its EEZ. The sport-fishing industry represents a high value input to its economy. but only operates within the first 50 nautical miles of its EEZ. The lack of patrol, enforcement and presence of commercial fishermen offshore has resulted insome illegal fishing activities by foreign fishing vessels. [ABSTRACT FROM AUTHOR]