1. Development of the fisheries, and
occurrence of new species in
Svalbard waters
Kristin Heggland, Harald Gjøsæter, Odd Nakken, Ole Arve Misund,
Jørgen Berge, Ole Jørgen Lønne
Arctic Change 2014
5. All fish in the Svalbard zone
Temperature: 5 yr running mean, Kola section
Cod
Haddock
Herring
Northeast Arctic cod
Haddock
Northern prawn
Greenland halibut
Saithe
Ling
Tusk
Wolffishes
Redfishes
Halibut
Herring
8. Summary
• Large temperature variations
• Large variation in landings of fish from the Svalbard area
• There is a link between the two
• One large and one small scale story
- Different mechanisms
- Larger ecological effect inside the fjords?
9. Takk for meg og Takk til…
Thank you for your attention!
Editor's Notes
In recent years boreal fish species already precent in the Barents Sea, such as Cod and Haddock, have increased in biomass, and new species, such as herring and mackrel have started to occur in fjords on the west coast of Svalbard
Svalbard as study area because the area is highly influenced by AW
already well affected, what might be the potential effects
Gateway to the Arctic how species are affected by climate changes
Ocean climate is important for the distribution of fish species
ANIMATION: our study area is located in the high Arctic on the continental shelf around Svalbard
In warm climate years in the Barents Sea, the Northeast Arctic cod are shifting its distribution north and east, whereas in cold climate years they are concentrating in the southwestern pars of the Barents Sea
Atlantic Water is the main heat source in to the Barents Sea, and the Arctic Ocean
Atlantic Water originates form the Gulf Stream, passing trough the Faroe-Shetland channel as the North Atlantic Current, going along the Norwegian continental shelf as the Norwegian Atlantic Current, before it divides in to two main branches north of Norway as the North Cape Current, going east to the Barents Sea, and to the north as the West Spitsbergen Current, trough the Fram Starit
The magnitude of Atlantic water entering these regions has been shown to be correlated to the North Atlantic Oscillation and local pressure fields
August, how far south the sea ice edge has been positioned
The ocean climate is also affecting the sea ice
1979 - 2006: sea ice extent have been reduced by 10% per decade
Average sea ice thickness reduced
Combined this gives a loss of about 50% of the sea ice volume
The reduction in sea ice extent opens up new areas for fish to utilize, and greater areas are available for trawling
Norwegian Atlantic Current: Flow along the continental shelf
Two branches North of Norway
1) North Cape Current -> East
2) West Spitsbergen Current -> North to the Fram Strait
Polar Front
NAC is the main heat source in the Polar Ocean and the areas we have been investigating
Barents Sea: shallow shelf (240m), annual sea ice cover
Svalbard: Cold Arctic coastal current, AW along the continental shelf -> Arctic Front
Kola section, temperature represents AW also for western parts of BS
Other sections more west, but not as long time series
Fishery is conducted on the shelf mainly in the Barents Sea, but there is also some fishery along the continental shelf on the west coast of Svalbard
Statistics on landings form the Svalbard zone collected by ICES, and later the Ministry of Fisheries have been produced continuously since 1929
The Svalbard zone is indicated by the black box
ANIMATION: Most of the fishery is conducted on the shelf area around Bear Island, but also along the continental shelf of western Spitsbergen
The grey line indicates the Polar Front.
This is known as a very productive area.
In years with high influx of AW the PF is pushed northwards
For the entire period of the fishery data, there have been conducted temperature measurements at the Kola section form the top down to 200 m
ANIMATION: Even though the Kola section is located southeast for the area we have been investigating
The temperature variability in the Kola section has been shown to give a fairly good representation of the climate fluctuations in the Atlantic domain
The black line is the fishery of the 10 most commercially important species, and groups, plus herring in the Svalbard zone from 1929 to 2013
The species are: Northeast Arctic cod, Haddock, Northern prawn, Greenland halibut, Saithe, Ling, Tusk, Wolffishes, Redfishes, and Halibut
During the 1920s, and particularly in the 1930s a fishery, mainly with trawl, developed in the Barents Sea
In fact the fishery was so good in the northern areas, that infrastructure for landing cod was established in Kongsfjorden (green arrow) in the 1930s
ANIMATION: In general the landings, and the temperature form the Kola sections seem to be faily well correlated
When temperatures are higher boreal species migrate further north
Temperature has also shown to be important for the recruitment of several fish species inhabiting these areas, and this may explain the time lag between peak in temperature, and peak of landings
Other factors such at quotas, what price the fishermen will get for the different catches, fuel price, and demand in the market will affect the landings.
Also fishing pressure is an important factor. If the fishery causes higher mortality than the recruitment the stocks will decline
ANIMATION: Cod is the most important species in the Svalbard zone
in the 1950s Sætersdal and Hylen were concerned with the declining trend in landings of the spawning cod.
compared to before the war, the ratio of spawning cod had been reduced relative to that of the young cod, however the fishery continued
for a period of over 30 yr, annual fishing mortality was above any calculated safe level
on average the recruitment was lower than the annual outtake-> numbers and biomass of cod decreased
Which can explain the low landings in the warm periods the 50s and 60s
High recruitment of cod have been show to be associated with high temperatures or to occur at the onset of a warming period
The recent increase in temperatures and a moderate fishing pressure combined have allowed for the cod stock at present to be at its largest since the monitoring of the stock started
ANIMATION: Haddock is a more warm water species than the cod
ANIMATION: Herring is a temperate specis
Did occur in the late 20s early 30s, was completely gone for a ling time, before re-appearing in the middle of the 90s
NOKO OPPSUMMERANDE SMART: tar i mot forslag med stor takk
In fjords off the West Coast of Svalbard new fish species have recently started to occur
As you can seen in the figure the coastal current in Svalbard is of Arctic origin, coming form the north, going around south cape, and along the west coast to the north again
the WSC of Atlantic origin goes along the continental shelf outside the coastal current
The difference in density creates a front, the Arctic Front, inhibiting AW advecting in to the fjords of Svalbard
However, under favorable conditions, usually wind induced, the front develops meanders and eddies providing heat flux towards the shelf and fjords
This happened in 2006. AW was advected in to Kongsfjorden
Winter temperature: Feb - April
ANIMATION: average temperature before 2006
ANIMATION: average temperature after 2006
ANIMATION: Increase in average temperature of 1.5 degrees
ANIMATION
Cod:
Caught since mid-1990s,
early 2000s adult cod were regularly caught using a bottom trawl.
Capelin:
Since 2006 adults have increasingly become common (Hop and Gjøsæter, 2013).
In 2007 the diet of kittiwake have in shifted from polar cod to capelin in Kongsfjorden (green arrow)
Since 2010 both adults and juveniles have been regularly sampled
ANIMATION
Young haddock:
First recorded in 2006
Juveniles (<10cm) have been observed regularly since 2008
adult have been observed regularly since 2009
Young cod less then 10 cm:
Started to appear in catches in 2008 juveniles
Herring:
Recorded in Kongsfjorden, with few individuals since 2006 (Hop and Gjøsæter, 2013).
First recorded in Isfjorden in April 2012 (adult specimens only).
Regular occurrence of juveniles in Isfjorden since 2012.
Mackerel:
first time on record September 2013
Sea Ice Retreat Alters the Biogeography of the Bering sea Continental shelf. Muter et al. 2008
Potential species: Redfish Hollowed et al. 2013
thermal habitat preferance
food availability
increasing population -> good recruitment
what we see in the western barents sea can be expected to be seen in other colder regions as the water temperature continue to warm up
in warm year when the polar front is pushed northwards fish assembleges have also been seen to move northwards. weideman et al. 201?
Learn form history, what we see to daybhave heppened before, can help us to for see what can happen in the future
