No fishing is allowed in no-take zones, thus protecting species and their habitats. At SLU Aqua, we monitor the development of no-take zones in Sweden and provide recommendations on how these areas can be most effectively designed.
The Department of Aquatic Resources (SLU Aqua) has been tracking the development of fish stocks and ecosystems in Sweden’s no-take zones for many years. Our research aims to develop recommendations on how such areas can be designed to become an effective tool for ecosystem-based marine management.
In Sweden, 1% of coastal and marine areas are no-take zones (as of 2022). With the EU committing to implement strict area protection in 10% of its marine areas, we are now facing a unique increase in ambition. The area of no-take zones will therefore need to be significantly expanded in the coming years, presenting a unique opportunity to strengthen fish stocks and improve habitats.
No-take zones we have investigated in the project
The no-take zone at Storjungfrun and Kalvhararna in Gävleborg County was established in 2011 to protect the declining populations of sea-spawning whitefish. The area covers 147 km², with a large buffer zone of just under 4000 km², where fishing is prohibited during the whitefish spawning season. The no-take zone was reopened to fishing in 2016 and is now only protected during the spawning period.
Summary of results:
The adult whitefish population increased rapidly in the no-take zone and the spawning protection area compared to the area that remained open to fishing. The increase was stronger in the no-take zone.
Sea trout also increased significantly after the no-take zone was established.
Commercial fishers’ catches of whitefish in the Bothnian Sea increased after the no-take zone and the large spawning protection area were established.
After the no-take zone was reopened to fishing, catches of whitefish declined and the difference between the areas disappeared. This shows that the positive effects of a no-take zone can disappear quickly if the regulation is removed.
Read more:
Chapter 6 (sid 52) "No-take zone for whitefish in the Bothnian Sea" in Aqua reports 2022:20.
Lännåkersviken at Gålö in the Stockholm archipelago is an important spawning and nursery area for pike, perch and pikeperch and has been renowned among sport fishers. Due to heavily decreased stocks of pike and pikeperch, a no-take zone was established as an emergency action to reduce pressure on the highly exploited populations.
The no-take zone covered an area of 1.7 km2 with a similar sized spawning closure as a buffer zone. The no-take zone was reopened to fishing in 2016 and is currently only closed during spawning season.
Short summary of results:
Catches of adult pike and pikeperch increased by a factor of 5-11 in the no-take zone compared to the reference area open to fishing. This highlights that even small no-take zones can increase populations of large predatory fish if they have highly localised populations.
No positive effects were found for perch in the no-take zone, likely due to high predation by mainly great cormorant. The initial positive effects of closure on pike populations disappeared in conjunction with grey seal disturbance in the area.
Catches of pike, perch and pikeperch decreased in the no-take zone when reopened to fishing. This is likely due to a combination of predation by grey seal and great cormorant and fishing pressure from recreational fisheries.
More info
Chapter 7 (page 22) "No-take zone for pikeperch, pike and perch in the Stockholm Archipelago (Gålö), Baltic Sea" in Aqua report 2022:20
Licknevarpefjärden is a 3.7 km2 coastal bay in Östergötland. The area is a nature reserve with no fishing allowed. Fishing was prohibited in 1979 to reduce the disturbance on breeding white-tailed eagles, not to protect fish.
Because the area has been protected from fishing for decades, it provides us with a unique opportunity to study and understand natural, unfished populations of the Baltic Sea.
Short summary of results:
There were significantly more and larger pike and perch in the no-take zone than in the reference area. This highlights that even small no-take zones can increase populations of large predatory fish if they have highly localised populations.
Predation by large predatory fish have resulted in decreased numbers of prey species, particularly cyprinids. This indicates that no-take zones can also counteract effects of eutrophication, as some cyprinid species can contribute to eutrophication effects.
Slower growth in individual pike was found, likely as a result of intraspecific interactions. On the other hand, perch was found to grow faster. Reasons behind this are currently investigated.
During recent years, perch and pike have decreased in the no-take zone, likely as an effect of increased predation by grey seal and great cormorant.
More info
Chapter 9 (page 138) "No-take zone for pike and perch in Licknevarpefjärden, Baltic Sea" in Aqua reports 2022:20
The waters around Gotska Sandön, north of Gotland, are known to have high abundances of turbot and European flounder. A 360 km2 no-take zone was established in March 2006 in order to evaluate the effects of a fishing closure on these flatfish populations. The no-take zone partly overlaps with a marine reserve.
Short summary of results:
Higher abundances of turbot and European flounder were found in the no-take zone compared to the reference area where fishing is allowed.
Lower growth rates were seen in both turbot and European flounder due to density-dependant factors.
Hydrodynamic modelling showed that a significant proportion of flatfish larvae are exported from the no-take zone to waters around Gotland, indicating that the area is important for Gotland’s turbot and flounder populations.
During the latest assessment in 2021, the abundances of both turbot and European flounder were still higher in the no-take zone compared to the fished areas. However, the density of large turbot had decreased in both the no-take zone and the reference area, while densities of juveniles were the same as before. This indicates a high level of mortality in adult turbot, but the reasons behind this are unclear.
More info
Chapter 8 (page 111) "No-take zone for flatfish around Gotska Sandön in the Baltic Sea" in Aqua reports 2022:20
Sweden and Denmark jointly established a no-take zone in 2009 to protect the threatened cod population in Kattegat. This was unique since the regulations were decided within separate national Swedish and Danish legislations. The no-take zone is 426 km2, located offshore and surrounded by a large buffer zone (2600 km2) in which some fishing is allowed.
Short summary of results:
An initial increase of cod was found in the no-take zone compared to the reference area.
After changing fishing regulations outside the no-take zone in 2016, commercial catches of cod increased and the cod population decreased to an all-time low in 2021.
There is an urgent need for a recovery plan and stricter fishing regulations in order for the cod population to recover.
Norway lobster, dab and lemon sole also increased in the no-take zone compared to the reference area.
The benthic fauna within the no-take zone changed over time, indicating a shift towards a more natural assemblage when the physical disturbance from trawling decreased and the predation by fish increased.
More info
Chapter 10 (page 162) "No-take zone and partially protected areas to rebuild cod in the Kattegat" in Aqua reports 2022:20
In 2003, no-take zones were established around artificial reefs in Tanneskär and Buskär in the area of Vinga, close to Gothenburg. New artificial reefs were also constructed at the same time. This was done to compensate for the lobster habitats that were destroyed during the expansion of the shipping lane to Gothenburg port. The two no-take zones cover an area of 4.5 km2.
Short summary of results:
The density and size of lobster increased over time in the no-take zones compared to the reference areas, both by the artificial reefs and in natural habitats. After 10 years of protection, lobster egg production was three times higher in the no-take zones than in the reference areas.
Predatory fish also increased the first few years after the establishment, but the difference between the no-take and reference area had disappeared when the area was reassessed in 2015.
Abundances of small crayfish decreased rapidly after the establishment of the no-take zones. This indicates that the lobster and large predatory fish regulate the abundances of these species.
In summary, the whole fish and crayfish community changed over time in the no-take zones compared to the reference areas, indicating that the food-web structure changed to a more natural state.
More info
Chapter 11 (page 194) "No-take zone and artificial reefs for lobster and predatory fish at Vinga, Kattegat" in Aqua reports 2022:20
Havstensfjorden, a protected coastal inlet by Orust in Västra Götaland, has historically been a very productive fishing ground. Due to heavily extinguished fish populations, a 13 km2 no-take zone with a 140 km2 buffer zone was established in 2010 as an emergency measure to protect cod, turbot and European place.
Short summary of results:
The abundance of young cod increased in both the no-take zone and reference area after fishing was forbidden. Adult cod abundance is, however, still very low.
Cod eggs have been found in both the no-take zone and reference area, indicating that there is still a small spawning stock in the area.
No trends over time were found for European plaice since the establishment of the no-take zone. However, when looking at the whole time series from 2002 and onwards, there is a long-term decrease in densities of both large individuals and total abundance.
The abundance of large turbot has decreased since the establishment of the no-take zone.
Populations of cod and flatfish have been heavily overfished for decades in the area and it may therefore take a long time for these populations to recover.
More info
Chapter 12 (page 221) "No-take zone for cod and flatfish in the Havstensfjord, Skagerrak" in Aqua reports 2022:20
The no-take zone for lobster in Kåvra, where all fishing except handheld gear is forbidden since 1989, is 2.6 km2 and situated outside Brofjorden in the county of Västra Götaland. The no-take zone was established in order to conduct studies on lobster ecology and the effects of fishing on lobster populations.
Short summary of results:
The density and size of lobster has continuously increased within the no-take zone during a period of thirty years, which has increased the reproduction potential by 7-9 times.
Adult lobster is stationary. Larval dispersal models also show that lobster larvae display limited dispersal in the area.
No effects of the no-take zone was found on local fish populations.
Densities of edible crabs were lower in the no-take zone compared to the fished areas, possibly as an effect of negative interactions with lobster.
More info
Chapter 13 (page 272) "No-take zone for lobster and wrasses at Kåvra, Skagerrak" in Aqua reports 2022:20
International experience with the effects of fully protected no-take zones has shown that they result in both more and larger fish in the protected areas, and can also have a positive effect on fish stocks and fish in surrounding areas. In Europe, no-take zones have been used as a management tool to a very limited extent, and knowledge has therefore been quite restricted. Sweden holds a large portion of the total area of no-take zones in Europe.
We have evaluated the no-take zones that have been in place the longest, and the results are summarised in the report "Long-Term Effects of No-Take Zones in Swedish Waters". In general, a clear recovery has occurred among the target species for protection, i.e., fish and crustaceans that are important for both commercial and recreational fishing. The number of individuals and the size of the fish have increased in the no-take zones compared to reference areas where fishing has continued to be allowed. The increase has also been rapid, showing that no-take zones are an effective measure to quickly strengthen weakened stocks.
Ecosystem effects
We have also observed effects on fish communities as a whole and on benthic fauna in the no-take zones, indicating that this measure can also have positive effects on entire ecosystems. Large predatory fish are highly sought-after target species for both commercial and sport fishing. These species often show the most significant positive effects when no-take zones are established.
At the same time, predatory fish play a crucial structuring role in ecosystems. By regulating the presence of smaller species, such as crabs and small fish, their prey increases, including small crustaceans and molluscs. These in turn reduce the occurrence of filamentous algae, which competes with large, perennial vegetation. In this way, predatory fish alleviate the negative effects of eutrophication in coastal zones, contributing to healthier habitats.
Overall, this suggests that no-take zones can be useful not only in fish management but also in nature conservation.
Effects of spawning protection areas
Spawning protection areas are zones where fishing is prohibited during the breeding season and are commonly used as fishery conservation measures along the coast. However, knowledge about the effects of spawning protection areas is more limited compared to fully protected no-take zones.
A comprehensive study of the effects of spawning protection areas on perch and pike has been conducted within the Refisk project. The results show that pike have benefited from the protection, but perch have not. Some effects on the food web have also been observed.
Along both the east and west coasts, there are numerous spawning protection areas around river mouths where sea trout and salmon spawn. A previous evaluation shows that clear effects on the density of sea trout and salmon in the rivers can be observed after an average protection period of three years.
