Annual Eel Migration Begins at Hopkins River

A resident of Warrnambool, Victoria, recently observed the annual migration of hundreds of short-finned eels from the Hopkins River into the ocean, marking the beginning of a long-distance journey to breeding grounds.

Observation Details

Michael Neoh observed the eels at the mouth of the Hopkins River in Warrnambool, Victoria. He estimated at least a thousand eels were present, with some individuals measuring over one meter in length.

Neoh noted the water was clear and described some eels being pushed back by wave surge as they attempted to cross from the river into the ocean. Some eels were also observed temporarily stranded on sand between waves during the attempt.

"It was amazing to be there in person. It looked spectacular. It was such a clear day, clear water, and I saw them trying to get across the riverbank. It was difficult because a few of them tried to get into the ocean, but the wave surge pushed them back."

The Migration Cycle

The observed migration is an annual event for the species, which is known as Kooyang to the Gunditjmara First Nations people. The eels migrate from freshwater to the ocean at the end of their life cycle to breed.

According to fisheries scientist Lachlan McKinnon, the specific triggers that initiate migration are not fully understood.

"No one really knows what triggers eels to do it, and even which eels decide to go. It's likely a combination of their age and size, but there are seasonal triggers for them to migrate out to sea to go somewhere in the Coral Sea to spawn."

The journey to spawning grounds in the Coral Sea covers an estimated distance of 3,000 kilometers. This migration is a one-way journey; the eels die from exhaustion after breeding.

Life Cycle and Return Journey

The offspring of the migrating eels eventually return to freshwater habitats. These habitats are located in Victoria, New South Wales, Tasmania, New Zealand, and parts of the South Pacific.

Michael Neoh noted that some eels returning to the Hopkins River climb Hopkins Falls to reach their habitat. He also expressed interest in observing the return of juvenile eels to the river.