As if our marine life didn’t have enough to deal with from overharvesting, pollution and habitat loss they now face rising ocean temperatures that have them heading for the poles. Climate change is the culprit. Scientists say that movement by species on land and sea is nothing new but climate change has increased the speed of their movement.
Curtis Deutsch, a University of Washington researcher, says in an article for the journal Science, that it is not only warmer waters driving the migration but a drop in oxygen levels that occurs when the oceans warm. The combination of those two factors is shifting them away from the tropics and towards the poles.
The earth’s oceans are warmer now than at any point in the last 50 years. The movement of the marine plants and animals are changing marine food webs and affecting the plants and animals that depend on them. The warming temperatures can affect the metabolism, life cycle and behavior of marine species. For many species temperature is a cue for reproduction, so temperature changes could affect breeding. Not all fish will survive in their new environment threatening their population survival.
A study has shown that fish in the North Sea have moved further north or into deeper water in response to rising sea temperatures. Black sea bass, once most common off the coast of Virginia have moved up to New Jersey. Pygmy killer whales have been spotted off the coast of Washington. According to New Scientist magazine, wildlife officials and fisherman in Alaska have seen skipjack tuna and thresher sharks.
Bloomberg News reported that polar bears have been observed eating white-beaked dolphins in the Norwegian Arctic. Scientist believe the dolphins, lured by warmer waters northward, became trapped under the ice and were killed when coming up for air. While these dolphins are known to visit the area in warmer months, this is the first time they have been reported that far north in early spring. This is the first recorded instance of these dolphins being the prey of polar bears.
The warming waters not only have implications for our marine animals and plants but also for fisheries and the people who depend on them. In developed countries, the fish migration poses costly challenges for the commercial fishing industry. In less developed countries and the tropics the movements threaten a critical source of food.
This is just more evidence of the repercussions caused by a rapidly warming planet.
