Archive for February, 2015


Thursday, February 26th, 2015
WARMING SEAS: CHANGING ECOSYSTEMS In The Times today 21/2/2015  Oliver Moody writes about research results of Spanish and British marine scientists on the effects of the rise of 1.31C in sea temperature in the northeast Atlantic continental shelf region over the last three decades. The government’s Centre for Environment, Fisheries and Aquaculture Science (CEFAS) has already suggested that consumers “will have to learn to love a range of exotic fish species as North Sea stocks change”. Dolphins killing salmon 1

 Dolphins feeding on salmon in the Moray Firth

What does all this mean for our wild Atlantic salmon and sea trout? I think the most obvious effect on fisheries is that species with a preference for colder waters, such as the sprat, are moving northwards. Meanwhile, species of fish that prefer warmer waters such as horse mackerel, mackerel, sardines and anchovies, have already spread into the North Sea and Baltic Sea. Pentland Firth APHA

The Pentland Firth, most northerly of British mainland coasts

This ‘Mediterraneanisation’ of the seas around northwest Europe – our seas and coastal waters – may bring rewards to the UK fishing industry if species such as red mullet move north. But there are also implicit threats coming from sea warming. For example, it is already established that cod and salmon are moving away from the warmer waters of the southern North Sea. Terrestrial warming and higher temperatures of freshwater habitats may also cause declines of trout stocks, which of course includes sea trout. Some views expressed in the angling media are based on the hope that the natural resilience of Atlantic salmon will adapt to environmental changes. They rightly point out that salmon have survived at least two ice ages, which involved them abandoning hot river catchments and colonising new ones revealed by the retreating ice. It is important that such views do not encourage complacency. It is particularly important that river managers continue to prepare for climate change by catchment-wide planning to mitigate effects of warmer water, especially in spawning and juvenile habitats. Pristine burn on Hoy. Low density of juvenile trout

A moorland tributary, susceptible to high water temperatures on hot summers days

Along our coasts and at sea we do not have the ‘hands-on’ ability to address such environmental impacts as we do in fresh water, but we can give migrating salmon and sea trout much better access to and from rivers by killing fewer of them.

From the AST viewpoint we need to monitor what is happening to sea temperatures in the ocean, along our coasts and in fresh water. We must also keep up to date with arrivals and departures in our coastal waters of predators and prey species. Importantly, we must also continue our dialogue with European sea fishing colleagues on the Pelagic Advisory Committee (PELAC) to ensure that migrations of wild Atlantic salmon are not being accidentally disrupted by pelagic trawlers.