Human-induced trauma to marine animals is a concern – Monterey Herald


Pacific Grove >> The discovery of a dead sea lion at Lovers Point on Friday morning sparked concern over the cause of his death.

While Bay Net volunteers reported the body had no indication of injury, growing tensions over human-caused trauma to wildlife have put many on the lookout for human interactions with marine life. . And a new study gives good reasons.

More than 600 marine mammals admitted to rehabilitation centers along the central coast between 2003 and 2015 showed signs of human-induced trauma, report researchers from the Marine Mammal Center in Sausalito in a recent study. California sea lions made up the majority of those admitted, bearing wounds from plastic debris, fishing gear and even gunshots.

There have been 123 cases of marine debris and 43 cases of gunfire involving marine life in Monterey County.

“It shouldn’t be like that,” says Daniela Barcenas de la Cruz, lead study author and veterinarian who worked with the Marine Mammal Center. “It’s disturbing how we affect the animals in the ocean.”

The study continued a previous review published in 1999 that looked at human-induced injuries to mammals over the previous 12 years. Given the growing human population and the high demand for marine food resources since then, the team took an interest in how things were going.

“There is always an interest in knowing how many trends are due to natural causes and how many are man-made,” explains Barcenas de la Cruz.

Using data on stranded marine mammals collected from 11 counties in California between 2003 and 2015, scientists determined the main causes of human-induced trauma before classifying them as related to fishing or non-marine debris. related.

Of the more than 11,000 animals admitted over the 12 years, six percent showed signs of human-induced trauma, the study found, with half of them considered fishing-related and the other to other sources. Animals such as California sea lions, harbor seals, elephant seals, various species of whales and the Guadalupe alien fur seal have fallen victim to marine debris, fishing gear, collisions with boats and gunshot wounds.

In the 12 years studied, there were 169 cases of shootings.

For Noah Oppenheim, executive director of the Pacific Coast Federation of Fishermen’s Associations, the illegal use of weapons against a marine mammal was surprising.

“I can’t think of a situation where shooting a sea lion would be justified,” Oppenheim said. “From an ethical standpoint, from a legal standpoint, from every standpoint, shooting a sea lion is wrong. “

Cases of gunshot wounds in marine mammals have become rarer since the last investigation in 1999, the study concluded. But the number of catches in marine debris has increased overall, whether in the form of fishing nets, fishing lines, rubber O-rings, ropes and discarded plastic bags.

“Marine litter impacts about 10% of the patients we see here,” said Giancarlo Rulli, communications associate at Marine Mammal Center, in an email. So far this year, 59 seals and sea lions have been admitted due to such negative human interaction.

These findings add to recent attention to whale entanglements in marine debris, a form of human-induced trauma less represented in the study due to the rarity of entangled whales washing ashore.

Entanglements of more than 160 whales over the past three years, according to National Oceanic and Atmospheric Association records, prompted the Center for Biological Diversity in Oakland to take legal action against the California Department of Fish and Wildlife in October and petition the federal government. to classify the fishing industry as a danger to whales in November.

“We take this issue of marine entanglement very seriously,” Oppenheim said. “No commercial fishery wants to catch marine mammals. To avoid future events, fisheries are paying special attention to maintaining fishing nets so that whales cannot easily catch them, says Oppenheim. And constant communication between boats about a whale’s location also helps prevent unwanted entanglements.

Even so, marine hotspots in Monterey and Santa Cruz counties had the most animals touched by humans, a result researchers suspect to have come from food-rich waters that attract marine mammals, fishermen, and tourists. from the shores of Monterey Bay.

“We all have needs,” says Barcenas de la Cruz. “As humans, we need food that we get from the sea. But these animals also feed on these resources. So that creates competition. And that means humans and animals will interact more frequently.

But the researchers hope the study results will boost legislation to tackle human-induced injuries, generate new ideas for future prevention, and motivate people to be more environmentally conscious.

“Knowing that the amount of garbage or lines or fishing nets has been one of the most common causes of human interaction is very worrying,” said Barcenas de la Cruz. “Proper disposal of our waste – we could make a fair contribution with that. “

An earlier version of this story incorrectly reported that the Guadalupe fur seal was endangered.


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