Climate change: impacts on our vision for a healthy and biologically diverse marine ecosystem

The variety and distribution of marine species are being altered by climate change, although it is not the only factor. Cold-water species of plankton, fish and intertidal invertebrates are retreating northwards around the UK and the ranges of southern species are expanding. Fishing pressure remains the principal cause of changes in the abundance of most fish species, but climate has probably also played a role in some cases. For example, the decline of prey species (particularly sandeels) has resulted in low breeding success of black-legged kittiwakes and other seabirds.

	WHAT IS ALREADY HAPPENING	WHAT COULD HAPPEN	CONFIDENCE
Plankton Find out more... SAHFOS	A northward shift of 1000 km of warmer-water plankton, with a similar retreat of colder water plankton, has been observed in the north-east Atlantic over the past 40 years as the seas around the UK have become warmer. There is a correlation between plankton shifts and changes in various fish stocks.	Continued increase in sea temperature and ocean acidification may exert a major influence on plankton variability, with implications for primary production and climate control.	MEDIUM
Fish Find out more... MBA	Abundances of some warm-water fish species (e.g. tuna, stingrays, triggerfish) have increased in southern UK waters during recent warming periods (1950s, 1980s – 2002), while declines were apparent during cooling episodes (1920s, 1960 – 1970s). Observations of rare fish migrants to UK waters cannot be directly attributed to climate change. Cold water species have retracted north in some regions (e.g. North Sea) but not in others.	Continuing temperature rises are likely to further change fish distributions.	LOW
Marine mammals Find out more... SMRU	There is little useful information on the effects of climate change on marine mammals.	There appear to be no special circumstances that suggest marine mammals around the UK should be severely affected. Sea-level rise may affect current haul-out sites for seals, but the rate of change and creation of new sites may allow their populations to adapt. As top predators in the food chain, marine mammals may be impacted by changes affecting the food chain that supports them.	LOW
Seabirds Find out more... JNCC, CEH	Poor breeding success, reduced survival and population declines of black-legged kittiwakes in recent years have been strongly linked to climate change, in particular to warmer winters and changes to their fish prey populations (e.g. sandeels). Evidence suggests other species may have been similarly affected.	Further declines in some seabird populations are expected. Anticipated sea-level rise may reduce available breeding habitat for shoreline-nesting species (e.g. terns) Potential increased storminess could detrimentally affect cliff-nesting colonies of seabirds.	MEDIUM
Non-native species Find out more... Cambridge University, SAHFOS	New marine life is arriving into our waters both by migration and by human introduction. The number of different non-native species is increasing in marine habitats and some are causing major ecological changes. Distributions of non-native species are currently limited by water temperature. Warmer UK waters over the last three decades are facilitating the establishment of some of these species.	Future temperature increases could enable a wider range of species to invade and become established.	MEDIUM
Inter-tidal species Find out more... MBA, MECN	Southern, warm-water species on rocky shores in the UK have increased in abundance and range with rising temperatures (e.g. purple acorn barnacle has extended its range by 170 km since the mid 1980s), whilst northern, cold-water species (e.g. common tortoiseshell limpet) have decreased in abundance.	Continued extension and retraction of ranges with rising temperatures of southern and northern species respectively. Some new species will become established whilst others will disappear from our shores.	MEDIUM
Seabed ecology Find out more... University of Liverpool, MECN	Climate processes such as sea temperature and waves can directly influence the abundance and species composition of seabed communities. Localised effects through fishing impacts, habitat modification and contaminants are also important and make it difficult to assess the influence of climate change.	Unknown.	LOW

WHAT IS ALREADY HAPPENING

WHAT COULD HAPPEN

CONFIDENCE

Plankton

Find out more...

SAHFOS

A northward shift of 1000 km of warmer-water plankton, with a similar retreat of colder water plankton, has been observed in the north-east Atlantic over the past 40 years as the seas around the UK have become warmer.

There is a correlation between plankton shifts and changes in various fish stocks.

Continued increase in sea temperature and ocean acidification may exert a major influence on plankton variability, with implications for primary production and climate control.

MEDIUM

Fish

Find out more...

MBA

Abundances of some warm-water fish species (e.g. tuna, stingrays, triggerfish) have increased in southern UK waters during recent warming periods (1950s, 1980s – 2002), while declines were apparent during cooling episodes (1920s, 1960 – 1970s). Observations of rare fish migrants to UK waters cannot be directly attributed to climate change.

Cold water species have retracted north in some regions (e.g. North Sea) but not in others.

Continuing temperature rises are likely to further change fish distributions.

LOW

Marine mammals

Find out more...

SMRU

There is little useful information on the effects of climate change on marine mammals.

There appear to be no special circumstances that suggest marine mammals around the UK should be severely affected.

Sea-level rise may affect current haul-out sites for seals, but the rate of change and creation of new sites may allow their populations to adapt.

As top predators in the food chain, marine mammals may be impacted by changes affecting the food chain that supports them.

LOW

Seabirds

Find out more...

JNCC, CEH

Poor breeding success, reduced survival and population declines of black-legged kittiwakes in recent years have been strongly linked to climate change, in particular to warmer winters and changes to their fish prey populations (e.g. sandeels). Evidence suggests other species may have been similarly affected.

Further declines in some seabird populations are expected.

Anticipated sea-level rise may reduce available breeding habitat for shoreline-nesting species (e.g. terns)

Potential increased storminess could detrimentally affect cliff-nesting colonies of seabirds.

MEDIUM

Non-native species

Find out more...

Cambridge University, SAHFOS

New marine life is arriving into our waters both by migration and by human introduction.

The number of different non-native species is increasing in marine habitats and some are causing major ecological changes.

Distributions of non-native species are currently limited by water temperature.

Warmer UK waters over the last three decades are facilitating the establishment of some of these species.

Future temperature increases could enable a wider range of species to invade and become established.

MEDIUM

Inter-tidal species

Find out more...

MBA, MECN

Southern, warm-water species on rocky shores in the UK have increased in abundance and range with rising temperatures (e.g. purple acorn barnacle has extended its range by 170 km since the mid 1980s), whilst northern, cold-water species (e.g. common tortoiseshell limpet) have decreased in abundance.

Continued extension and retraction of ranges with rising temperatures of southern and northern species respectively.

Some new species will become established whilst others will disappear from our shores.

MEDIUM

Seabed ecology

Find out more...

University of Liverpool, MECN

Climate processes such as sea temperature and waves can directly influence the abundance and species composition of seabed communities.

Localised effects through fishing impacts, habitat modification and contaminants are also important and make it difficult to assess the influence of climate change.

Unknown.

LOW