Climate change will be challenging for aquaculture in Shetland, conference told

Climate change will pose a series of challenges to Shetland’s aquaculture industry, a major conference heard today.

Rising sea temperatures, an escalating number of pests and parasites and an increase in major storms are all issues the industry can expect to deal with in the future.

The warning came from general manager of Shetland Aquaculture Davie Sandison as part of a presentation before delegates to a conference at the Shetland Hotel.

He pointed to projections from the inter-governmental panel on climate change suggesting temperatures will rise by 1.8 to four degrees globally by 2100.

“Our species requires to be grown in an optimal temperature range. We happen to be very lucky in the Shetland isles to be absolutely in the right range at the moment.

“We tend to find we’re farming fish in waters that are maybe six degrees to 13 or 14 degrees, maximum, temperature – which is ideal.

“You have stress levels that are enhanced by rising temperatures and lower oxygen levels … then that makes those species more vulnerable.”

He said rising temperatures could also be behind the proliferation of sea lice.

“It isn’t just the fish themselves that are susceptible to temperature ranges. We find that one of the issues that become more of a problem with rising temperatures is the rise in the range of fish pests, parasites and other environmental challenges that will flourish.”

He added rising water levels were “not necessarily” a challenge as they could be incorporated into a normal production cycle.

Less welcome, he said, could be increased incidents of algal blooms, along with jellyfish swarms and other species.

But he insisted some aspects of climate change, such as higher temperatures, could lead to better growth from the fish.

“If we have a milder winter and get a better growth in the winter months, that leads to a better spurt of growth in the summer time.”

New species could increasingly become a factor in a rapidly changing climate. Mr Sandison the growing proliferation of snake pike fish was already causing problems for bird populations.

“Birds are now picking them up and potentially trying to feed them to their young instead of sandeels. They’ve got a skeleton, so they’re not much use for a young chick.”

He added dramatic weather patterns could emerge more regularly. Major storms which had occurred once a century may now happen every 25 years.

However he stressed opportunities were born out of rising sea temperatures, which could prove useful for any fledgling halibut producers.

“Not so long ago in Shetland I was very keen to tell the rest of the world that we were an example in the UK of how we could diversify from salmon farming into lots of other activities.

“We tried halibut farming for a while. Commercially it was on the cusp of whether we could do it or not. There are no longer any halibut farms operating in Shetland, however there have been some breakthroughs in the last few [years] which could make it interesting again.”

The conference, Coastal Communities, Climate Change and Aquaculture, was hosted by Aberdeen University.

The meeting focused on the adaptation of coastal communities to climate change and learning from industry experience.