Department of Environment, Land, Water and Planning compliance operation program manager Mark Breguet said the decision to humanely euthanise the Australian Fur Seal on Thursday was not made lightly.

"All management options, including translocation, were considered," Mr Breguet said.

"Translocation was evaluated as being unsuitable due to the seal's aggressive behaviour and the likelihood it would return to the boat ramp or become an issue at another site."

The Standard previously reported concerns the seal had blocked access at the Portland boat ramp.

Mr Breguet said members of the public reported the seal had acted aggressively in recent weeks, particularly when seeking fish scraps discarded by anglers.

He said the operation showed how quickly wild animals became dependent on humans for food. He urged anglers to be responsible with fish scraps.

"It serves as a reminder that seals are wild animals with natural hunting instincts to source food. By feeding seals or incorrectly discarding fish scraps, humans disrupt this instinct," Mr Breguet said.

"Discard scraps in a bin or take your catch home to clean it. Do not throw them into the water or feed them to seals."

The seal's death comes a month after authorities euthanised another seal in Port Fairy following similar public safety concerns after it also became dependent on scraps from fishing activity.

READ more:

The Department euthanised eight south-west seals in the past five years, three due to public safety and five due to animal welfare.

Under the Wildlife (Marine Mammals) Regulations 2009, the offence for feeding a seal carries a $242 on-the-spot fine, and a maximum fine of up to $3223.80.

DELWP patrolled Port Fairy and Portland during peak weekend periods in past years but no fines were issued.

Have you signed up to The Standard's daily newsletter and breaking news emails? You can register below and make sure you are up to date with everything that's happening in the south-west.