A mass of thousands of jellyfish at Hobart's waterfront dock may look like a natural phenomenon, but a leading scientist has warned its presence indicates something awry in the marine habitat.

An unprecedented amount of jellies are congregating on Hobart’s waterfront. While one expert says it will be a ‘once-in-a-lifetime’ opportunity, the situation is a worrying signal.

Police attended a protest by animal welfare activists on Hobart waterfront who called for an end to one of Hobart’s decade-long tourist attractions. Police attended the scene after complaints ...