Over demanding market affects fisheries more than climate change

Fisheries that rely on short life species, such as shrimp or sardine, have been more affected by climate change, because this phenomenon affects chlorophyll production, which is vital for phytoplankton, the main food for both species.

Disclosed by the research "Socioeconomic Impact of the global change over the fishing resources of the Mexican Pacific" headed by Ernesto A. Ch?vez Ortiz, from the National Polytechnic Institute (IPN).

Work performed at the Interdisciplinary Center of Marine Sciences (CICIMAR) from the IPN, indicates that in the last five years there have been no "spectacular" changes attributable to climate change, what has affected the fishing resources more is the over demanding market.

"Globally, a great part of the fishing resources is being exploited to its maximum capacity, several have overpass its regeneration capacities and are overexploited" Ch?vez Ortiz points out.

The specialist at CICIMAR details that the research consisted in exploratory weather and fisheries analysis, and confirmed what has been intuitively said for a while: a lot of the variability in the fishing is due to climate change, the problem is that evidence hadn't been found to prove it.

"In the research we found a clear and objective way to show it: we took historical data from FAO regarding fisheries, available since 1950, compared it to the data of weather variability and found high correlations.

Change patterns were identified, for example, while in the 70's the sardine production increases, in the 80's it decreases below average levels, meanwhile shrimp fishing increased above average but decreased in the 90's.

This way, climate changes were identified in the mid 70's and late 80's that affected the fishing of sardine and shrimp in the Mexican Pacific Ocean, possibly attributable to El Ni?o. In the particular case of the shrimp, it effects are related to an input of water from the continent; for example, when there's a good raining season, there will be an increase in the crustacean production, which is reduced when it doesn't rain.

The researcher at CICIMAR clarifies that the analysis of the fisheries, examined in the guidelines of this project, used of a simulation model that allows to evaluate optimal exploitation strategies, possible change in the biomass of the analyzed resources, as well as the long term effects of climate change, like cyclones, and set them apart of those caused by the intensity of the fishing.

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North Atlantic atmospheric oscillation affects quality of cava

The quality of cava depends on technical factors such as fermentation, aging and bottling processes, which usually remain stable for years. Researchers from Malaga University (Spain) have discovered that oscillations in the North Atlantic -that affects European climate- also have an effect on the attributes of this sparkling wine. The years in which there is presence of the Azores anticyclone, there is a drop in the quality of cava.

The researchers Raimundo Real and Jos? Carlos B?ez, from the University of Malaga, have analysed the possible effects of the North Atlantic oscillation, known in scientific literature as NAO, on the quality of Spanish cava in a study published in the International Journal of Biometeorology.

The NAO is a microclimate index that reflects the atmospheric pressure difference between the Azores and Iceland, so the presence of an anticyclone in the Azores is positive and it is negative if there are areas of low pressure in that same area. This pressure difference that oscillates over time, has a direct effect on the weather conditions in the Iberian Peninsula.

"We discovered there was a connection between the NAO and the quality of cava between 1970 and 2008. The existence of positive NAO values during the months of March to August, when the grape is developing and maturing, reduced the capacity of obtaining top quality cava," Raimundo Real told SINC.

The North Atlantic oscillation plays a major role in weather fluctuations in the hemisphere. The phenomenon affects the climate in Europe and the Iberian Peninsula. It is related to temperature and rain variations in cava producing regions, which affects the physiological processes during the grape's period of maturity.

"The likelihood of obtaining a top quality cava is higher when the average value of the NAO is negative. This makes the average temperature in the cava region drop and the quality improves," the expert explained.

Inter-annual variations in the quality of cava are determined according to the different aromas and the amount of sugar in the grape. These qualities of the plant in turn, in one area of production, depend on weather conditions, such as cloud cover, temperature and rainfall to which the plant is subjected, particularly during the grape period (March to September).

Predicting the years of top-quality cava

The climate in the Atlantic Ocean, the Mediterranean basin and the surrounding continents shows considerable weather variability.

"During half of the years we analysed, the NAO values are intermediate and do not clearly affect the quality of the cava, but in the other half, the values are more extreme and lead to clearly favorable or unfavorable conditions for obtaining top-quality," says Real.

The information for 2012 pointed towards an 80% likelihood of obtaining a top-quality cava, while this likelihood is around 45% for 2013, always according to the model obtained. The model correctly predicted the 80% for the clearly favorable years for obtaining top-quality cava and the 70% likelihood of the clearly unfavorable years.

The NAO value between March and August can be calculated in the actual wine harvest time, while the quality of the cava can only be valued two years later. "This is important for being able to predict years of top-quality cava production, as well as for exploring the possible effects and variations of climate change on the quality" he concluded.

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