Last week, scores of local residents made their way to Sharp State Park in Pacifica, California, a 20-minute drive south of San Francisco, to view the body of a humpback whale that came ashore on 4 May.  When the 32-foot female humpback whale’s body came ashore, after days being tossed by waves, it was only the latest in a string of strandings along northern California’s Pacific coast.  Moe Flannery, a stranded marine mammal responder and manager of the Department of Ornithology and Mammalogy at the California Academy of Sciences, is quick to dispel a desire to look for conspiracy theories over the whales’ deaths.  “This is not a beaching,” she begins, “it is a stranding,” explaining that a stranding occurs when the animal washes ashore and does not deliberately go on to the beach. This usually happens after the animal is injured.  Flannery and the academy believe that it is “likely” the most recent whale was hit by a ship at sea and washed ashore after dying. Her team, which conducted the necropsy, says there were “signs of trauma consistent with blunt force”.  While Flannery does not deliver an exact cause of death – “because we were not there to witness the animal die” – she believes this death, and the others in recent weeks along the California coastline, are accidents and the timing is coincidental.  “We cannot make assumptions or theories of why there have been this number of incidents in recent weeks because we did not physically witness the trauma,” she argues.  On 14 April, also in Pacifica, a 48ft sperm whale washed ashore. Researchers are unsure of exactly what occurred in the ocean but report the whale was emaciated and had slight hemorrhaging, which could have been the result of a ship collision. Shortly after that incident, an orca came ashore north of San Francisco in Fort Bragg. According to researchers there, the orca appears to have been injured as a result of fishing nets and was also showing signs of hunger.  Then, on 24 April, two gray whales were stranded in Santa Cruz county, south of Pacifica. There were signs of trauma on one of the whales after what scientists believe was an encounter with an orca, but again, scientists could not give a definitive cause of death.  The latest stranding, in early May, has increased questions asking what is happening in the Earth’s oceans.  Oceans attorney for the environmental law organization Earthjustice Andrea Treece says the most common causes of whale deaths in recent years are the result of ships and the mammals being tangled in fishing gear and nets.  While numbers are limited due to scientists’ unwillingness to give definitive causes of death, collisions with ships are a serious threat to some species. Of the North Atlantic right whale, the International Whaling Commission says: “It is thought that mortality due to ship strikes may make the difference between extinction and survival for this species.”  Ships may not be the only culprits, Treece and other researchers argue. Commercial fishing lines also play a role in ocean life.  “One recent stranding saw the whale have its pectoral fin wrapped around with fishing lines,” Treece says.  In 2010, the National Marine Fisheries Service reported 25 sightings of entangled whales, with at least five dying as a result of their injuries, and others emaciated, thin and on the verge of death; the findings were similar to researchers’ statements in Fort Bragg.  For some the Fort Bragg orca also brought back concerns over the US military’s use of sonar along the Pacific coast, which researchers have linked to disrupting marine life, and even resulting in the death of marine mammals. In January, the navy announced a new project that would install some 720 sonar-pinging buoys off the Pacific coast from northern California to the Canadian border.  Earthjustice staff attorney David Henkin says: “Sonar and other human-caused noise in the ocean has been implicated in marine mammal strandings worldwide. This is another possible cause of strandings that should be investigated.”  Treece says that humanity’s role in climate change cannot be separated from the strandings investigations. She argues that “we as humans have to look at our role” in the changing dynamics that encompass marine life, from changing temperatures to overfishing and other human activities.  “Food sources [are] shifting to unusual places and locations,” she says, and “we need to look at how we contribute to climate change and ocean conditions.”  Numerous studies have reported marine life is migrating to different waters as climate change’s effects on the ocean’s biodiversity take hold. This means traditional patterns of animal life are changing, disrupting centuries of established norms.  Treece puts forward an example of that change seen in Monterey Bay, where a large number of humpback whales have congregated to feast on the unusually dense population of sardines who have come into the bay. With sardines having been overfished along northern California’s coast over the past century, the unique appearance of these schools of fish in the bay waters has led to the whales pausing on their migration north to enjoy a few meals.  It is a sign of changing ocean conditions, which are resulting in whales and other marine life having their traditional migratory patterns disrupted by the need to find food sources in fresh locations.  “We saw a similar case in 2007, when a number of blue whales were hit by ships,” she continues. The cause appears to have been the change in location of blue whales’ natural food source, krill, which had moved into new waters, leading to the whales moving along with them. That led to ships that had previously not been problematic to the blue whales finding the animals in their lanes.  Researchers argue the environmental changes being reported should be part of the conversation. As ocean temperatures warm, and as overfishing becomes more evident, food sources are moving to different locations, which in turn is forcing migratory animals such as whales to alter their usual routes. As whales and other larger ocean life continue to meander along coastal areas in locations they previously had not been, a number of scientists believe the situation could lead to more human-caused trauma, including the rise of whales and other marine animals crossing shipping lanes more frequently.
A recent spate of whales washed up on the state’s beaches may be coincidence but ship strikes, fishing lines, sonar and climate change are all taking a toll