Ocean plankton, the world's tiniest creatures faces the threat of extinction. This may affect many local fisheries across the globe.
Unable to cope with the changing temperatures of ocean waters, Calanoid copepods, a species of old water plankton, faces the threat of extinction. Planktons are a vital food source for fish such as cod and hake. Many fisheries depend on abundant supplies of these fish and hence, a scarcity can spell disaster for the fish they rear.
"There is overwhelming evidence that the oceans are warming and it will be the response of animals and plants to this warming that will shape how the oceans look in future years and the nature of global fisheries," explained Deakin's professor of marine science, Graeme Hays.
Hays noted that while many researchers have conducted studies on the warming of ocean waters, not many have looked into whether and how certain species of marine life will survive these changing temperatures. As of now, the future looks bleak for many. Determining whether a species will be able to adapt is not an easy task as it involves years of observations spanning multiple generations.
For this study, the research team examined a 50-year time series from the North Atlantic on the distribution and abundance of two very common but contrasting species of ocean plankton, Calanus helgolandicus that lives in warmer water and Calanus finmarchicus that lives in cold water. Calanus finmarchicus is the scientific name for Calanoid copepods.
Researchers were surprised to find that even after 50 years, there were no signs of Calanoid copepods adapting to warmer waters. The consequences of this can be very drastic. Hays predicts that as the habitats of these creatures become restricted to the poles, they will become rarer and finally disappear.
"C. finmarchicus is a key food source for fish such as cod and hake," Hays further explained. "So continued declines in abundance will have a negative impact on the long-term viability of cold water fisheries in the North Sea and other areas in the southern part of their range. At the same time the continued increase in abundance of the warm water plankton, C. helgolandicus, will likely play a role in the emergence of new fisheries for warm water species."
