The artist said she hopes the mural will evoke questions from students, teachers and the wider community around the environment and the health of oceans.
"The health of our environment is under attack from corporations in the name of greed - the waters of Napier are no exception," she said.
"Commercial fishing and careless council storm water and sewerage systems have already left our Pegasus Basin in an all-time state of disease."
Sergent said she wanted to convey the threat oil and gas exploration, overfishing and pollution has on the Heretaunga coast.
"With the threat of oil and gas exploration always looming on the horizon, there is a lot to be concerned about - we need oil-free seas."
Keep New Zealand Beautiful CEO Heather Saunderson said she was amazed by both the quality and quantity of entries.
"Research has shown that the beautification of public spaces deters vandalism and anti-social behaviour such as littering and graffiti and increases civic pride," she said.
Artists nationwide submitted designs with the top 10 selected based on their environmental message, enhancement of the community and originality/creativity.
The other winners are based in Auckland, Christchurch, Wellington, Tauranga, Rotorua, Rangiora and Mangonui.
The winning designs received a $1000 grant, along with a $750 Resene paint voucher and other materials to paint their mural.