Melbourne Zoo Vets are treating a seriously injured Little Penguin, rescued from the St Kilda breakwater.

Senior Veterinarian Dr Helen McCracken says that the injury could have cost the bird its foot, and then its life, so it was very lucky to be rescued before it was too late.

The injury was caused by stray fishing line, which had wound so tightly around the Penguin's slender ankle that it cut through the skin and into the bone surface.

The entanglement also caused major swelling in the foot tissues, but fortunately the blood flow wasn't completely cut off, so the foot is still alive.

Dr McCracken says that some of the bone is dead, but that enough has survived to give the Penguin a good chance of full recovery.

She explains that if the Penguin hadn't been freed from the entanglement very soon, he would definitely have lost this foot and died.

The Penguin is receiving antibiotics, hidden inside the fish he is fed several times a day.

Dr McCracken has also prescribed medication to be used on the site of the wound, which will always be visible due to the permanent discolouration of the skin caused by the fishing line.

She says that the aim is to return the bird to the St Kilda colony as soon as it is able to fend for itself again.

Dr McCracken explains that even seemingly insignificant bits of rubbish in the marine ecosystem can cause devastating damage to wildlife, and she urges people fishing around the bay to dispose of any rubbish in bins, where it can't harm animals.