What is killing the ‘killer whales‘?
A calf died of sepsis after ingesting a traditional wooden hook. Another died of starvation due to a congenital facial deformity. Two other specimens died from serious injuries caused by collisions with boats.
One of the specimens did not overcome the infection caused by satellite marking for later monitoring. Another death was due to natural causes and the other two have been undetermined.
Despite their bad reputation, killer whales, which number about 55,000 specimens, have managed to establish themselves in stable populations. But, in the case of those observed off the coasts of the states of the British Columbia, in Canada, Washington and Oregon, in the United States, their situation is more delicate. Here their population, of just over 70 individuals, is considered in danger of extinction.
Scientists have detected infectious diseases, such as toxoplasmosis or sarcocystosis, nutritional deficiencies, infections from shark bites, among the other causes of death of these whales. While there is no single common cause of death, the researchers did determine that there was one theme that united them all at all ages: interactions with humans!
Although the research cannot offer a complete picture of the health and mortality of these whales – due to the state of the stranded specimens when analyzed – the report is the one that so far best reflects the threats that loom over these animals.
The orcas (Orcinus orca) were erroneously called English killer whales, a term that was adapted to the Spanish as killer whales. But in reality, the confusion stems from a poor English translation of killer whales, as they were called by the 18th century Spanish whalers, when they saw them attack and kill other larger cetaceans.
From 2004 to 2013, 53 of these odontoceous cetaceans were stranded on coasts across the globe and the causes of death for 42% of them were determined. Now, a study, led by the British Columbia Ministry of Agriculture, has made it possible to analyze these autopsies to identify the dangers these killer whales face and thus improve their conservation management.