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Temperature and hypoxia anomalies are observed in many coastal regions, and climate change is likely to cause a more frequent and intense occurrence of environmental extremes. Understanding their impacts on benthic populations is critical, especially on those with little or no mobility. In this contribution, the effects of hyperthermia (to 26[degrees]C) and hypoxia (to 1.0 mg [O.sub.2] [L.sup.-1]) were analyzed and compared with their combined occurrence through the evaluation of the physiological condition of juveniles of the green abalone Haliotis fulgens. Sudden, single-time exposure of 8 h and the recurrent exposure to 8-h weekly episodes for 6 wk were tested to identify changes in the physiological condition by estimating the respiration rate (RR), the biochemical contents (soluble protein [SP] and glucose [Glc]), and physicochemical variables (osmolality [Osm] and pH) in hemolymph, and energy status (adenylate energy charge [AEC]) was measured in the muscle. The strongest responses under sudden hyperthermia were an increase in RR and Osm as well as a reduction in SP, pH, and AEC, and under hypoxia and combined effects, reductions in RR, Osm, and pH were observed. Abalone's responses to the combined stressors under the recurrent regime were different, showing increases in SP and Glc contents and reductions in pH and AEC. Results suggest that under recurrent stress of hyperthermia or hypoxia alone, the juveniles of H. fulgens can adapt, whereas under recurrent events of the combined stressors, the observed response is similar to that of sudden stimuli (without evidence of adaptation). KEY WORDS: green abalone, Haliotis fulgens, temperature, hypoxia, sudden stress, recurrent stress, INTRODUCTION There is increasing awareness of the potential impacts of extreme events of high temperature (hyperthermia) and depletion of dissolved oxygen (hypoxia) in coastal marine ecosystems worldwide. Climate change projections [...]

The Gulf of California on Mexico’s west coast is approximately 1,250 kilometers long, with a climate ranging from temperate to tropical and flanked on both sides by deserts. It has great biological diversity, extreme tides and water characteristics, and is geologically active. The Atlas has a page for each scientific cruise, that could be found, in the Gulf since 1825 to nearly the present. Each page describes the cruise and displays a schematic cruise pattern. The Introduction is in English and Spanish. After the Introduction is a list of key words that have been used to describe the data collected and instruments used, but any word or words can be used to search the Atlas.

Green abalone (Haliotis fulgens) experienced severe biomass losses and massive mortality due to short-term marine climatic extremes. We studied green abalone behavior and energy expenditure in response to environmental stress. Acclimatized juveniles were subjected to hyperthermia (26°C), hypoxia (1.0 mg O2 L-1), the combination of both, and control conditions (18°C and oxygen saturation) using an automated system. The movement parameters of organisms were recorded by labeling and filming them, and the respiration rate was measured in hermetic chambers. There were differences in gross and net distance and velocity between the control and the combined stressors. Respiration was raised by hyperthermia, lowered by hypoxia, and further reduced by the combined stressors. All abalone that left the shelter during the night returned by daylight, while hypoxia and hyperthermia reduced this number. Research on environmental stress and movement strategies could lead to a more objective stress proxy. [ABSTRACT FROM AUTHOR]

ABSTRACT Stable isotopes (δ[sup.13]C, δ[sup.15]N) were used to assess differences in the diets of wild adult Haliotis fulgens and Huliotis corrugata. Temporal variations in the diets of these species were [...]

Some pods of gray whales (Eschrichtius robustus) breed every winter at three lagoons along the Baja California Peninsula and then migrate to feeding grounds on the Bering and Chukchi Seas. The number of whales arriving to the lagoons fluctuates yearly and is related to climate variability. We analyzed the documented climate effects on the whales over their distribution range and discuss the potential effects of global climate warming in their breeding areas. Our analysis indicates that global warming will be favorable for gray whale populations, but unfavorable for the Mexican whale-watching industry: favorable, because fluctuations in calf production have been positively correlated with the length of time that the primary feeding habitat was free of seasonal ice during the previous year. However, if gray whales change their breeding areas to northern bays, they will be exposed to new challenges, which will have repercussions on the whale-watching industry. We discuss these new challenges.

Sea-surface temperature satellite images of 21 years are analyzed to study El Nino-Southern Oscillation signal in the Gulf of California. The variability of sea-surface temperature observed during winter is due to disruption of the wind-driven upwelling corridor of the eastern coast.