Five people have died after a charter boat capsized in New Zealand and authorities are trying to find the cause. The 28-foot vessel was carrying 11 passengers just off the coast of Kaikoura, a small community on New Zealand’s South Island, on Saturday, September 10, officials said during a media briefing carried by 1News. “This is a tragic event that affects many lives, especially families and loved ones,” Mayor Craig Muckle told reporters. “Our sincere sorrow and condolences to you all.” Sea conditions were “perfect” and the waters were calm, Muckle said. The boat capsized around 10am, the New Zealand Herald reported. Rescue crews rescued six passengers, officials said. Divers recovered the five dead, their bodies trapped inside the flooded boat. The official cause has not been determined, but Muckle told news outlets that the boat likely collided with a whale. Whales are a common sight near Kaikoura, and a number of humpback whales are moving through the area at the moment, Mackle said. They have been spotted breaching the surface near shore. The passengers were members of the Nature Photography Society of New Zealand. The organization said it was “saddened by the tragic loss at sea” of five of its members, adding that “our thoughts are with the families of these members”. Mitchell Willetts is a real-time news reporter covering the central US for McClatchy. He is a graduate of the University of Oklahoma and an outdoor enthusiast living in Texas.