Scottish salmon farmers publish first monthly mortality data

The data, which covers all Scottish salmon farms, shows that between January and April this year monthly survival rates on farms ranged between 98.5% and 99%. Around 60% of salmon farms stocked with fish had less than 1% monthly mortality.

A first in farming sectors

In a press release, the Scottish Salmon Producers’ Organisation (SSPO) said the reporting is believed to be a first among all farming sectors in the UK and is at the forefront of international reporting for salmon farming globally.

SSPO chief executive Julie Hesketh-Laird said: “The health and welfare of salmon is hugely important to salmon farmers.

“This regular, voluntary publication is unparalleled and sets a precedent for transparency in business reporting. It sets a base line to show future trends and currently around two-thirds of active salmon farms have 99% survival rates.

“We hope this will be helpful to the progress of the collaborative Farmed Fish Health Framework initiative to further improve survival of salmon.” 

Progressive step

Scottish Government chief veterinary officer Sheila Voas said: “We welcome the fact that salmon farming is taking steps to be more open and transparent about the levels of mortality within the sector.

“Of course, what is most important is that we all work together to tackle mortality of any level, in any sector, to help reduce it to an absolute minimum. The recently published 10-year Farmed Fish Health Framework for Scotland is a progressive step towards that aim, bringing together producers, government and regulators to address the big issues in aquaculture.”

The SSPO said the published figures, which it collated on behalf of the industry, build on longstanding reporting to the Scottish Environment Protection Agency and Marine Scotland.

The new reports provide monthly farm-by-farm statistics for use by the Scottish Government’s Fish Health Inspectorate and scientists. Additional information on the causes of mortality is also provided, including extreme weather incidents, jellyfish, algal blooms, marine predators and disease.

97.4% survival

Notes accompanying each set of figures explain that the right-hand column of figures, Cumulative mortality over full production cycle (%), is the percentage of fish that have died on a farm during the entire production cycle, given as a percentage of the total number of fish that were initially stocked on the farm, and can only be reported once the entire farm has been fully harvested and fallowed.

The notes add that as cumulative mortality refers to mortality over the entire production cycle, “an industry-wide figure can only be calculated once all fish from a specific generation or year class have been harvested. It usually takes two years to rear a salmon to harvest.”

Because relatively few production cycles finished between January and April, only a handful of cumulative mortality totals are included in the figures. These range from losses of more than half of the fish set out at one site to a survival rate of 97.4% at another.

Links to the farm-by-farm data are available here.