Rising sea temperatures threaten survival of juvenile albatrosses

Ecologists from Woods Hole Oceanographic Institution in the US and the French National Center for Scientific Research (CNRS) studied a population of black-browed albatross at Kerguelen Island, part of the French Southern and Antarctic Lands, where 200 breeding pairs have been monitored annually since 1979.

Reaching a wingspan of 2.5 metres, Black-browed Albatrosses breed on these sub-Antarctic islands during the austral summer, laying a single egg in October that will hatch in December. The chicks fledge in late March at a size similar to that of an adult.

Climate affects this seabird species in complex ways. In this study, the researchers developed a matrix population model that takes account of the combined effects of climate variables and functional traits in order to understand the entire life cycle and how population growth may be affected in light of a changing climate. Functional traits such as body size, timing of breeding, and foraging behaviour all have an impact on demographic traits such as survival and reproduction.

They found that changes in sea surface temperature during late winter cause the biggest variations in the population growth rate, through their impact on juvenile survival during their first year at sea. The effects of climatic conditions on seabirds generally occur indirectly.

"Sea surface temperature is widely used as an indicator of food availability for marine predators because warmer temperatures usually result in lower primary productivity in marine ecosystems, ultimately reducing the availability of prey", said Dr Stéphanie Jenouvrier, a seabird ecologist at Woods Hole Oceanographic Institution.

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Shag diet diversifies with rising sea temperatures

20/11/2017

A new study has found that sea surface temperatures have a direct impact on the diet of European Shag, highlighting problems that future climatic warming and resultant sea surface temperature increases might impose on its populations.

Long-term changes in climate are affecting the abundance, distribution and phenology (or seasonal timing of life habits) of species across all trophic levels (or discrete hierarchies in an ecosystem). Short-term climate variability is also having a profound impact on species and their interactions. Crucially, species will experience long- and short-term variation simultaneously, and both are predicted to change, yet studies tend to focus on only one of these temporal scales. Apex predators are sensitive to long-term climate-driven changes in prey populations and short-term effects of weather on prey availability, both of which could result in changes of diet.

The study investigated temporal trends and effects of long- and short-term environmental variability on chick diet composition in a North Sea population of European Shags between 1985 and 2014. The proportion of their principal prey, Lesser Sandeel, declined from 99 per cent (1985) to 51 per cent (2014), and estimated sandeel size declined from 104.5 to 92.0 mm over the same time period.

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Does climate change herald sad end of cliff top kittiwake colony in Seaford?

Rising sea temperatures could threaten the future of the popular kittiwake colony at Splash Point in Seaford, according to the RSPB.

There is evidence of a link between rising sea temperatures and a reduction in the numbers of the birds’ main food source, sand eels.

If the colony cannot adapt to find another supply of food it will struggle to survive, the conservation charity warned.

In other parts of the country the impact of rising sea temperatures is already being felt.

Seabird declines are particularly serious in the Northern Isles of Scotland and some colonies in the South East have also been badly affected.

In the early 1990s there was a colony of almost 3,000 pairs of kittiwakes at Langdon Cliffs near Dover in Kent, but this colony has declined alarmingly and in the last few years only a few tens of nests have been recorded.

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