Currently, our planet is at the mercy of a global climate change. Warming affects everything, including the redistribution and number of marine life and fish in particular. It will result in a significant change in the structure and dynamics of food webs. The scientists undertake to make more accurate forecasts for the future only when studying the historical data of the planet.
Comparing them, they reveal very interesting facts. At the University of Barcelona the scientists conducted a study analyzing the potential impact on the distribution of Argentine hake as the sea warms. The study was based on an analysis of the structure of marine ecosystems that existed about 5 or 6 thousand years ago.
Then the temperature of the water resources was significantly higher than what is now, which influenced the movement of fish, spreading to the south, reaching the coast of the southern part of America. On the basis of historical data, the scientists calculate the ecological changes in the modern hake habitat. They focused their attention on the Atlantic coast of the island of Isla Grande in Tierra del Fuego, in Argentina. Today, hake is still the main type of industrial fishing here.
The scientists have collected samples from two archaeological deposits of ancient fish dating back to the middle Holocene. According to approximate data, the temperature of water resources then and now is close to the same indicators. Historical and current data provide a complete picture of the changes that will occur during the current global warming.
In the distant past, the hake population endured warming well. But after the next cold snap, the population in the north of Tierra del Fuego completely disappeared and its migration routes remained unknown. The scientists found fish remains using mitochondrial DNA analysis. The technique was then used to extract stable isotopes of carbon and nitrogen to study changes in trophic position and habitat use over time.
Thanks to this method, information was obtained not only about the ancient habitat of fish, but also the food that they ate. The general results of the study proved that the Argentine hake that lived on the Atlantic coast of Tierra del Fuego during the Middle Holocene, had a wider isotopic structure. In fact, hunters could literally catch fish on the shore.
From a fisheries perspective, this situation suggests a potential increase in shallow water resources in relation to Tierra del Fuego with important changes in the fishing industry in this region. And at the present stage of the planet's existence, this situation may repeat itself.