A 59-year-old Broome man has described how he survived an attack from a 2.5 metre saltwater crocodile at Secure Bay near Derby.

Bruce Rudeforth was fishing from a dinghy last week when the crocodile leapt into the boat and clamped its jaws around his right shoulder.

Mr Rudeforth says he escaped with a number of minor puncture wounds to his upper chest because he was able to fight the crocodile.

"Fortunately, my elbow was free and I was able to stand up fairly rapidly and whack it in the throat with my elbow and it fell off," he said.

The Department of Environment and Conservation's chief zoologist says he is unsure what prompted the unusual attack.

Zoologist Peter Mawson says the crocodile could have been desperate for food or overly familiar with fishermen in the area.

"One of the things about a very heavy wet season is that it puts a lot more water into the system, so more distance between each fish," he said.

"So, the crocs might be doing it a bit tougher but it's also possible that the croc has associated fishermen visiting the area with an easy meal or a free handout."