What is happening with the world’s oceans is no laughing matter. First, we have the news that the Carteret Islanders of Papua New Guinea have become the first entire community to be displaced by climate change, with their traditional home expected to be under rising seas by next year. You may not think that the fate of 40 families is major news but they have been shadowed by scientists for at least two years as tides have washed away their crops and rising sea levels poisoned those that remain with salt. Other islanders face the same fate and, already, the Maldives government is buying land in Australia in preparation for the seemingly inevitable day.
So, as the oceans swallow food sources, we’re confident that they will feed us through increased fish farming, aren’t we? Well, don’t celebrate too soon: salmon farming industry figures reveal that sea lice numbers are out of control in parts of the west coast and western isles of Scotland, source of much of the best salmon.
In Wester Ross, for example, lice numbers have been consistently over thresholds for a full year and the latest aggregated sea lice data, published by the Scottish Salmon Producers Organisation (SSPO), shows that in Q4 of 2013 sea lice numbers on farmed salmon were massively out of control in a number of areas.
The latest SSPO quarterly sea lice report (for October to December) reveals that average lice numbers were over thresholds in 13 out of 30 areas for which data is reported by the industry. The isles of Mull, Islay and Jura, the east of Lewis, North Uist and South Uist had sea lice levels well over the thresholds for treatment.
The Salmon & Trout Association Scotland (S&TA(S)) is calling for a cull of all the fish in the very worst affected farms – the kind of decisive action taken by the Norwegian authorities when they were faced with a similar problem.
Why are sea lice on fish farms such a threat to wild salmonids? Mainly because the impact of sea lice on wild salmon causes a very high loss (one third) of those returning to Irish rivers and both wild salmon and sea trout are in decline in Scotland’s ‘aquaculture zone’, in contrast to populations that have stabilised on the east and north coasts where there is no fish farming.