Optimism for aquaculture industry in marine pest management

Just like health and safety is now embraced as good business practice, marine biosecurity is now part of day to day life for marine farmers around the country who have eyes on the water to detect pests, improved practices in place to ensure gear and equipment is clean, and an ever-growing body of knowledge about pest species.

“Marine pests have been a challenge to marine farming since day one,” says Aquaculture NZ Technical Director Dave Taylor. “They come and go naturally, and in most cases we have learned to manage or farm around them.”

From farm to farm, there are a range of innovative tactics keeping marine pests at bay. From growing oysters inside baskets, to keeping mussels out of the tidal range preferred by marine pests, and taking meticulous care with hygiene when moving equipment and stock.

In support of these endeavours, Aquaculture New Zealand has worked extensively with researchers to understand species and what is needed to farm in the presence of pest species. In the main, that means understanding their life cycles so that farming activities can be timed around them – for example, holding off putting stock out until the water cools and pest abundance isn’t so high.

Waiting pays off. Without the delay there can be significant stock and crop loss due to fouling.

The industry, under guidance from Aquaculture NZ, has a clearly articulated national approach to marine biosecurity.

“We farm from the top of the North Island, right down to Stewart Island,” says Dave Taylor. “We understand how interconnected the marine environment is.”

Aquaculture New Zealand has developed biosecurity standards for each of the major species farmed – Pacific oyster, Greenshell mussels, and King salmon.

These standards guide the industry’s biosecurity management plans, which are constructed around operational zones that are aligned with boundaries of groups of regional councils who are also working together within marine biosecurity partnerships.

The industry targets the risk of movements between the operational zones and between management areas within those zones. The management areas reflect any regional or national rules in place, including Controlled Area Notices and Regional Pest Management Plans, and also the presence or absence of certain pest species.

For example, the eastern side of Coromandel Peninsula and Great Barrier Island don’t currently have Mediterranean fanworm, so therefore the industry ensures it is vigilant about cleaning and checking all equipment and vessels to reduce the risk of transporting it there.

The management areas also recognise those locations that are more likely to be the starting point for a new marine pest species. For example, farms located near to marinas that serve as Port of First Arrival facilities for vessels arriving from overseas will have measures in place to reflect that risk.

Measures include washing, drying, and disinfecting equipment that is to be moved, including ropes, floats, and sorting equipment. Sometimes stock gets a start in life in cool southern waters before moving north. When this happens, the biosecurity status of the area it is being moved from is checked against where it is going to, and if that checks out ok, it is washed and cleaned of fouling before it is relocated.

Now that a national program of pest surveillance is in place, Aquaculture NZ is advocating for more disease surveillance.

“We farm alongside wild populations of mussels and oysters and diseases they may carry can spread to our farms. We are working with the Ministry for Primary Industries on practical ways those risks can be managed,” he explains.

He is pleased to see wider national-scale efforts in the marine biosecurity space that aim to reduce the risk of marine pests being transported around the country. Aquaculture NZ is partnering with local government partnerships, researchers, and government to work on a coordinated approach.

He sees a lot of hope.

“We are being proactive and thinking about marine biosecurity in the same way that we think about health and safety,” he says. ”We look after our staff, and we look after our farms and farming environments through marine biosecurity. It’s day to day practice now to keep an eye out for pests, and to keep equipment clean, and to understand the risk of moving things. It’s not about eliminating risk, it’s about understanding it and putting practical measures in to reduce it as much as possible.”

He says the industry is very innovative and has a bright future.

“We will continue to be guardians for the marine environment.”