Beach visitors and seagulls do not go well together. For one, these water-bound birds are beggars – or rather, they have become beggars since the numbers of people in their environment has increased, as well as the food available to them.
Yet seagulls are nowhere near exasperation-levels, as their levels have been declining for a few decades. A recent study by the University of British Columbia concluded that the number of seagulls on the coast has been reduced by half since the 1980s. The cause, the study explains, is a reduction in seafood that is usually consumed by seagulls, which is shellfish and small fish.
It’s Not Just the Seagulls
With changes to the marine environment occurring faster than anticipated, marine life is now threatened from multiple quarters, according to a 2011 report published in PNAS.
Plastic abounds, and that has been documented enough and in much detail; pollution, both chemical and acoustic, add stress factors that have been unknown to marine populations until a few decades ago; ocean water is getting warmer and acidification is on the rise. That translates into many cold-water species being replaced by warm-water ones, as documented by a team of scientists from the University of British Columbia.
While that could lead to an increased and diversified catch higher north, there is also a double adverse reaction associated with it: a reduced number of species in the tropics, a displacement of species in the usually colder waters by the migration of warm-water species and a disruption in the food chain, both in the ocean and for the people who rely on the ocean.
The reason the seagull study is relevant, the authors point out, is because normally seagulls feed on a variety of small marine life. In time, they transitioned to finding additional sources of food on land, such as garbage and earthworms. Yet that is not enough to keep the population at healthy reproduction levels.
Also, the study points out, two other species of marine birds, Marbled Murrelets and Western Grebes have declined by 90 percent since the 1950s and 70s, respectively.
The disappearance of birds – albeit often unnoticed – signals deeper problems. Ocean acidification, a 2013 study said, leads to thinner, slower growing shells and skeletons in oysters, clams and sea urchins, and it also affects free-swimming sea snails, a favorite food for salmon. Ocean acidification is believed to affect the way salmon smell in the water, which can affect their development and feeding efficiency.
A few years ago, scientists warned that corals could be extinct within the next 50 years. Recent analysis of the health of corals in oceans further deepens the worry that humans are causing changes to the ocean waters that will affect marine life and possibly cause losses we may unprepared to deal with or reverse.
The only way to slow down the process and allow oceans to rebuild themselves is to reduce the use of fossil fuels. Relying on renewable resources that do not pollute or change the state of the environment is the only way we can prevent species from disappearing and allow future generations to learn from our mistakes.