(Fox News) – Scientists admit they are baffled by a rise in aggressive orca activity, with the whales ramming boats along the Spanish and Portuguese coasts, according to reports by the Guardian.

The number of reported incidents involving orcas has risen over the summer months, with researchers noting that interactions between the whales and boats are not unusual, but the level of aggression displayed in July and August is “highly unusual.”

Researchers speculate that it might be competition for tuna populations along the coast that has led to some distress among the whale populations. Alfredo Lopez, coordinator for the Study of Marine Mammals in Galicia, said orcas make their way up the coast each September to chase tuna. Since 1999, two of five pods common to the area have learned to take tuna from fishermen drop lines, with several sustaining injuries from the lines as a result.

“We see marks caused by fishing lines,” Jörn Selling, a marine biologist for Firmm whale watching and research foundation, told the Guardian. “We hear about young orca getting hooked.” However, the events are still considered unusual. “These are very strange events,” says Ezequiel Andreu Cazalla, a cetacean researcher. “But I don’t think they’re attacks.

Rocio Espada, who works with the marine biology laboratory at the University of Seville, said she was astonished by what she’s heard. “For killer whales to take out a piece of a fiberglass rudder is crazy,” Espada said. “I’ve seen these orcas grow from babies, I know their life stories, I’ve never seen or heard of attacks.” READ MORE