In the span of just three months last fall, five blue whales-federally protected under the Endangered Species Act-died in the northern waters of the Santa Barbara Channel during their annual pilgrimage though the region. It was a drastic blow to an already diminished population. Though a necropsy on one whale proved inconclusive and another was never examined, scientists linked three of the deaths to collisions with ships. In the wake of deaths, the Channel Islands National Marine Sanctuary Council mobilized a subcommittee-which included scientists, ship captains, fishers, and law enforcement-aimed specifically at preventing such deaths when the blue behemoths return to area waters this June. With the summer migration season fast approaching, the group reported back to the council for the first time last week at a meeting in Santa Barbara, unveiling preliminary strategies and monitoring techniques they hope will illuminate the complex circumstances surrounding the prior whale deaths but will also work to prevent future incidents. Environmental Defense Center chief counsel Linda Krop summed up the group’s efforts: “Our most immediate goal right now is get some sort of precautions in place to help protect the blue whales by the time this year’s migration begins.”
Hunted to near extinction throughout the first half of the 20th century, blue whales are the largest animals to ever inhabit the planet and have enjoyed a relative population upswing in recent years, with the most populous stock of an estimated 1,744 inhabiting the Eastern Pacific. Grabbing news headlines when their massive corpses washed ashore at beaches near Ventura’s Faria County Park and La Conchita between September and November last year, the whale deaths marked the largest recorded die-off of the leviathans in single year within the state of California, according to data complied by the subcommittee.
Furthermore, the deaths happened within 90 days of one another in a relatively small area, as opposed to 1988 and 2002, the years with the next-highest death tolls, when three such blue whales were found dead months apart in areas as far removed from each other as Marin County and San Diego. Though debate existed among Sanctuary Advisory Council members as to whether the 2007 incidents constitute an alarming trend, the National Oceanic and Atmospheric Administration’s National Marine Fisheries Services (NMFS) recently classified the deaths as an official Unusual Mortality Event, meaning that they were not only unexpected but that they also require “immediate response” from the appropriate agencies. According to a 2004 NMFS study, the maximum number of blue whale deaths the Eastern Pacific population can sustain without potentially perilous consequences is 1.4 deaths a year. Putting this fact in context with other sea-dwelling creatures, one councilmember remarked bluntly, “If this was fishing, we’d be screwed.”
One possible explanation of last year’s mortality spike was the occurrence of large-scale krill populations-blue whales’ primary food source-in the middle of major shipping lanes. Realizing the need for an understanding of krill distribution, whale locations, and shipping traffic patterns, the subcommittees called for an improved monitoring system of all three. This includes the continuation of aerial surveys and the timely distribution of this info to ships traveling through, as well as seasonally imposed speed limits of 10 knots in the affected areas. Additionally, even with the confirmation that ship-versus-whale smash-ups caused at least three of the fatalities, other possible factors remain. “There could very well have been some underlying problems-like domoic acid, noise pollution, or disease-contributing to the deaths,” Krop said. To understand these variables, the committee is also looking into expanding water quality and underwater acoustics monitoring. It is also discussing possible shipping lane tweaks and having lookouts on vessels. A final area of concern for the committee is who exactly will be responsible for carrying out these activities and, more importantly, how they will be paid for.
The subcommittee hopes to report back to the council once again in late March with a more detailed presentation before making its final recommendations to Sanctuary Superintendent Chris Mobley in May.