The southern right whale and the kelp gull share the seas of the southern hemisphere. They have coexisted for thousands of years in balance. But in Peninsula Valdes, east of the province of Chubut, in Argentine Patagonia, have entered into “tension.” The battle between seagulls and whales in Patagonia is escalating. The seagulls harass the whales and their calves.
With their beaks, birds manage to tear off small pieces of skin and even fat from mammals. They exert a “parasitic feeding”, which generates injuries and stress, especially in the young. A new study published in the journal Biology Letters, from The Royal Society of the United Kingdom, explains it. He suggests that seagull pecking could have a negative impact on the whale population.
Landfill problem
Attacks decrease the survival levels of their offspring. This could alter the long-term population growth of whales. Why it happens? It has to do with garbage dumps near the coast and those derived from fishing discards. The birds have access to more food and their population increases. This overpopulation ends up harming the whales.
Every year, a thousand whales arrive at the Valdés Peninsula to reproduce. But the pecking of the seagulls interrupts these activities and harasses them. These changes demand more energy expenditure from mammals. The stings were first reported in the San José Gulf in the 1970s. They then spread to the entire coastal area of Peninsula Valdés.
Sustained harm
The percentage of mother whales and their calves with injuries caused by seagulls is alarming. It went from 2% in the 1970s to 99% in the 2000s. At first, attacks focused mainly on mothers with babies. Then, newborn calves became the main target.
The battle between seagulls and whales in Patagonia is unequal. But one possible solution is to better regulate the garbage dumps that attract more and more seagulls. Another problem with them being fed garbage is that they have begun to show genetic malformations. As always, the hand of man ends up unbalancing the natural balance.
