Scientists have discovered a giant squid swimming near Western Australia without ever seeing it. Instead, they found its DNA in seawater samples.
Researchers from Curtin University detected the giant squid, known as Architeuthis dux, using environmental DNA or eDNA. This method works because animals constantly shed tiny pieces of themselves into the ocean through skin, mucus, and waste. By filtering and studying seawater samples, scientists can identify which species have recently passed through.
The giant squid is one of Earth's largest invertebrates. These creatures typically grow 10 to 13 metres long, weigh up to 275 kilograms, and have eyes as wide as 30 centimetres. They live in deep water and are almost never seen alive. Giant squids had not been recorded in Western Australian waters for more than 25 years.
During a deep-sea survey of submarine canyons near the Nyinggulu coast, about 1,200 kilometres north of Perth, the team collected over 1,000 water samples. They detected the giant squid's DNA in six separate samples across two canyons.
But the giant squid was just one discovery among many. The eDNA survey identified 226 species total, including sleeper sharks, deep-diving whales, and fish never before recorded in Western Australia. Many DNA sequences matched nothing in scientific records, suggesting vast amounts of unknown sea life still waiting to be discovered.