ABSTRACT Local and regional climate trends drive rates of change in coastal ecosystems. To better understand local climate, 35-year-long time series of air temperature, relative humidity and rainfall were analyzed along the reef corridor of the southwestern Gulf of Mexico. Data came from a climatological model and to assess its local performance, differences with in situ records were estimated when available. All three variables showed coherence with the record of the North Atlantic high-pressure system (also known as the Bermuda High) at similar times and periods between 4 to 8 and >10 years, evidencing the influence, at this regional scale, of El Niño Southern Oscillation (ENSO) and the Atlantic Multidecadal Oscillation (AMO). Positive and negative anomalies showed linear trends depicting an increase of warmer and moister events during a seasonal climatology at the reef corridor of the southwestern Gulf of Mexico and a relatively higher correlation (> 0.5) with the AMO mode. Return periods of extreme values varied between 5 and 10 years. In general, trends and extreme events showed similar patterns at a regional scale, but the increase in rainfall is expected to be larger near the central location of the study area. A higher frequency of extreme events could threaten local ecosystems and human populations; therefore, plans and actions at local scales of governance are needed to achieve preemptive climate adaptation.

RESUMEN Las tendencias climáticas locales y regionales impulsarán las tasas de cambio en los ecosistemas costeros. Se caracterizaron series temporales de 35 años de duración de la temperatura del aire, la humedad relativa y la precipitación en el sistema arrecifal del suroeste del Golfo de México. Los datos provinieron de un modelo climatológico, pero para evaluar su fluctuación local, las diferencias con los registros in situ se estimaron cuando los registros estuvieron disponibles. Las tres variables mostraron coherencia con el registro de alta presión del sistema de alta presión del Atlántico norte en tiempos similares y en periodos de 4 a 8 y > 10 años, lo que evidencia la influencia, a escala regional, de las señales de El Niño Oscilación del Sur (ENOS) y la Oscilación Multidecadal del Atlántico (AMO). Las anomalías positivas y negativas mostraron tendencias lineales que representan un aumento de eventos más cálidos y húmedos dentro de una climatología estacional en el área de estudio del Golfo de México, y presentaron una correlación relativamente alta (> 0.5) con el modo AMO. Los periodos de retorno de valores extremos variaron de 5 a 10 años. En general, las tendencias y los eventos extremos mostraron patrones similares a escala regional, pero el aumento de la lluvia puede ser mayor en la ubicación central del área de estudio. Una mayor frecuencia de eventos extremos podría amenazar los ecosistemas locales y a la población. Son necesarios planes y acciones de gobierno a escala local para lograr una adaptación preventiva al clima.

ABSTRACT Background: The Pacific sardine is a small pelagic fish which supports the most important fishery at national scale. Goals: This paper analyzes the catch information generated by the commercial fleet operating in the Gulf of California from 1969 to 2016 in order to identify the catch trends and the presence of the harmonic components that is related to environmental variability. Methods: Fast Fourier Transformation (FFT) was applied to the time series in order to establish the dominant frequencies. The Singular Spectrum Analysis (SSA) method was used to separate the trend and harmonic components. Each harmonic component was correlated to the Southern Oscillation Index (SOI), the Pacific Decadal Oscillation (PDO) and the Solar Activity data. Results: The FFT showed dominant frequencies at 7 and 11 years. An increasing linear trend was identified from 1969 to 2008 with a decreasing linear segment from 2009 to 2016, as well as two harmonic components of different frequencies (7 and 11 years respectively). The trend and the two harmonic components explain 87.49% of the total variance of the capture. The first and second harmonic components correlated positively with SOI (r= 0.2921, r= 0.3870 respectively), while the second harmonic component correlated negatively with solar activity (r= -0.5313). There were no correlations with the PDO. Conclusions: The fluctuations of Pacific sardine in the Gulf of California are mainly due to three factors: increased catch, the influence of the El Niño events and the influence of the solar activity cycle.

RESUMEN Antecedentes: La sardina monterrey es un pez pelágico menor que sustenta la pesquería más importante en términos de volumen a nivel nacional. Objetivos: En este trabajo se analiza la evolución temporal histórica de la captura comercial de sardina Monterrey generada por la flota pesquera, que opera en el Golfo de California de 1969 a 2016 con la finalidad de identificar la tendencia y presencia de componentes armónicos en las capturas que se relacionen con la variabilidad ambiental del área de pesca. Métodos: A los datos de captura se les aplicó la transformada rápida de Fourier (TRF) para obtener las frecuencias dominantes y el método “Singular Spectrum Analysis” (SSA) para separar la tendencia de las capturas y los componentes armónicos. Cada componente armónico fue correlacionado con el índice de Oscilación del Sur (IOS), Oscilación Decadal del Pacífico (ODP) y Actividad Solar. Resultados: La TRF mostró frecuencias a 7 y 11 años. Con SSA se identificó una tendencia lineal creciente de 1969 a 2008 y decreciente de 2009 a 2016, así como dos componentes armónicos (7 años y 11 años, respectivamente). La tendencia y los dos componentes armónicos explican el 87.49% de la varianza total de la serie de captura. El primero y segundo componente armónico se correlacionaron positivamente con el IOS (r= 0.2921, r= 0.3870 respectivamente), mientras que el segundo componente armónico se correlacionó negativamente con la actividad solar (r= -0.5313). No se presentaron correlaciones con la ODP. Conclusiones: Las fluctuaciones en las capturas comerciales de sardina Monterrey en el Golfo de California son dadas principalmente por tres factores: Incremento en las capturas, la influencia de eventos de El Niño y la influencia externa de la actividad solar.

ABSTRACT A multibeam sonar combined with an Acoustic Doppler Current Profiler (ADCP) were used at the Veracruz Reef System (VRS), Gulf of Mexico, during the spawning period of August 2016 in order to elucidate plankton trajectories within the study area. The new high-resolution bathymetry provided the location of 50 coral reefs, 27 more reefs than known at the VRS. Most of those reefs are submerged reefs located at depths greater than 40 m. The total coral reef area of the VRS was calculated in 70.1557 km2. Only ~10% of the total area corresponds to submerged reefs. Forty-eight species were identified, seven more than known species at the VRS, 45 of the order of Escleractinia and 3 of the order of Anthoathecatae. Acropora prolifera, a hybrid, was also identified in most reefs. All species were observed in the emerged and submerged reefs. The distance at which the three local river discharges (Jamapa, La Antigua, and Actopan) brought sediments to the VRS was calculated. Those are inappropriate areas for coral settlement or development due to sediment transport and temperature and salinity fluctuation. Finally, light penetration was measured at 19 m depth near one reef structure during August 2016 suggesting that even during cloud coverage and rain periods there was a light bioavailability at the sampling point.

ABSTRACT Sea level, water temperature, and wind stress data were obtained from the Western Gulf of Mexico to elucidate the relationship between sea level changes and meteorological variables in a tropical coral reef system. Sea level and water temperature data were measured with a series of acoustic Doppler current profilers anchored at a depth of approximately 13 m in the Veracruz Reef System. The barometric and wind stress data were obtained from an automatic coastal weather station. Principal Component Analysis was applied to the series to determine the relative influence of the different meteorological variables on sea level. The seasonal variability of sea level is evident in the year-long data (September 2008 to April 2010) with a thermal expansion during the summer. Barometric pressure was found to be the second strongest forcing mechanism of sea level variability and not the first one. Opposite to what would be expected in protected coastal areas where the wind forcing mechanism on sea level may not be as important. The local winds were the main forcing mechanism of the sea level variability from March to September, while the meridional winds were more important than local winds from October to February.

Este estudo analisou o papel das forçantes barotrópica e baroclínicadas marés na agregação e dispersão do ictioplâncton no sul do Golfo do México. A amostragem do ictioplâncton e o cálculo dos parâmetros hidrográficos foram realizados durante Setembro de 1992 num ponto fixo de 180 m de profundidade, perto da quebra de plataforma (19º32'N - 92º38.5'W). Uma amostragem de tipo yoyo com CTD foi realizada durante 24 h e amostras biológicas foram tomadas a cada 2 h. Estas medidas foram combinadas com dados de densidade da água e velocidade obtidas de simulações do modelo do Sistema Regional de Modelo dos Oceanos (ROMS). Uma termoclina e duas haloclinas foram detectadas. O número de Froude aumentou com uma defasagem de 2 h com relação à maré barotrópica, sugerindo a existência de uma maré baroclínica. A agregação e a dispersão do ictioplancton mostraram variações verticais tanto em abundância quanto no número de taxa e larvas, com defasagem de 5 h em relação à máxima maré barotrópica e esteve em fase com a oscilação da termoclina. A oscilação vertical foi atribuída a um controle hidráulico forçado pela maré interna.

The role of vertical barotropic and baroclinic tidal forcing in the aggregation and dispersion of ichthyoplankton in the Southern Gulf of Mexico was analyzed in this study. Samplings of ichthyoplankton and the determination of hydrographic parameters were performed during September 1992 at a single point of 180 m depth, near the shelf break (19º32'N - 92º38.5'W). A 24 h CTD yo-yoing casting and biological samples were taken every 2 h and these measurements were combined with water velocity and density simulations from the Regional Ocean Model System (ROMS). One thermocline and two haloclines were depicted. The Froude number increased with a 2 h lag with respect to the maximal barotropic tide, suggesting the existence of a baroclinic tide. Aggregation and dispersion of the ichthyoplankton showed vertical oscillations in the abundance and the numbers of taxa and larvae with a 5 h lag with respect to the maximal barotropic tide and were in phase with the thermocline oscillation. The vertical oscillation was attributed to a hydraulic control forced by the internal tide.

Current velocity data in the Southern Bay of Campeche, Gulf of Mexico, were obtained from March 1997 to May 1997, in order to compute tidal ellipses and phase lags in the region. Tidal ellipses and phase lags were calculated via a least squares fit method coupled with nodal modulation from the hourly time series. Constituents P1 and K2 were inferred from K1 and S2, respectively. The K1 component is dominant in the southern shelf of the Bay of Campeche, a region of mixed tides with semidiurnal dominance at the Arcas Kay sill, and a transition region between Arcas Kay and the southern-western stations. Vertical differences in tidal current amplitudes were negligible. There was a significant phase lag from surface to bottom. The sense of rotation for the tidal ellipses near Arcas Kay was negative, while at other stations it was positive. Arcas Kay has a strong influence on tidal currents because of vertical phase and sense of rotation variation with depth.

Datos sobre la magnitud y dirección de las corrientes fueron obtenidos en la Bahía de Campeche, al sur del Golfo de México, de marzo a mayo de 1997, para obtener las principales componentes de marea en la región. Las elipses y fases de las diferentes componentes de marea fueron obtenidas mediante un ajuste por mínimos cuadrados acoplado con una modulación nodal a partir de las series horarias de corrientes por marea. Los constituyentes P1 y K2 se infirieron a partir de los constituyentes K1 y S2, respectivamente. Los resultados muestran la dominancia del armónico K1 en la plataforma continental al sur de la Bahía de Campeche, una región de mareas mixtas con dominancia semidiurna en la zona del umbral de Cayo Arcas y una región de transición entre Cayo Arcas y las estaciones al oeste en la zona de estudio. Las diferencias en las amplitudes de las corrientes de marea en la vertical fueron despreciables, mientras que las diferencias en las fases muestran un retraso significativo entre la superficie y el fondo. El sentido de rotación de las elipses de marea en Cayo Arcas es negativo, mientras que en las otras estaciones fue positivo. Cayo Arcas tiene una fuerte influencia en las corrientes de marea ya que su fase y sentido de rotación varían.