No-take zones

Last changed: 30 April 2024
Measuring lobster

In no-take zones, all fishing is prohibited, which allows for the protection and recovery of marine populations and environments. The Swedish University of Agricultural Sciences (SLU) have monitored the fish populations and ecosystems in Sweden’s no-take zones for a number of years. The results will facilitate the process of providing recommendations on how no-take zones can be designed to become efficient tools in ecosystem-based management.

In Sweden, 1% of the coastal and pelagic waters are no-take zones (2022). However, we now face a unique opportunity to protect and restore species and environments, since EU has committed to strict protection in 10 percent of the ocean by 2030. The coverage of no-take zones will therefore need to increase greatly within the next few years, which provides  a promising opportunity to strengthen our fish populations and restore habitats.

Effects on targeted species

Worldwide, no-take zones are found to increase both fish abundance and size in the protected areas, sometimes with positive effects spilling over to adjacent areas open to fishing. In Europe, no-take zones are rare and the knowledge of their use as a management tool is therefore limited. A large portion of the total area of no-take zones in Europe is found in Sweden.

The long-standing no-take zones of Sweden have recently been evaluated and synthesised in a report that was published in 2022. In most of the coastal areas, there was a strong recovery in species targeted by the commercial and recreational fisheries in the protected areas. The abundance and size of fish increased in the no-take zones compared to the areas where fishing was still allowed. The response was rapid, showing that implementing no-take zones is an efficient way of strengthening weak populations.

More info

Long-term effects of no-take zones in Swedish waters (Aqua reports 2022:29)

 

Ecosystem effects

Effects of the protection on fish communities and benthic fauna are found in no-take zones, showing that prohibiting fishing  can also have a positive effect on the ecosystem as a whole. In Sweden, both commercial and recreational fishers target large predatory fish and therefore these species often recover rapidly in no-take zones.

Large predatory fish have an important structuring role in the ecosystem by regulating smaller species like crabs and smaller predatory fish, which in turn control their prey, i.e., small crustaceans and molluscs. These prey species graze on filamentous algae, decreasing their presence, hence enhancing large, habitat-forming vegetation that the filamentous algae otherwise compete with. In this way, large predatory fish limit the negative effects of eutrophication in coastal environments and contribute to thriving habitats.

No-take zones are therefore not only useful in fisheries management but can also be useful in marine conservation.

More info

Top-down control as important as nutrient enrichment for eutrophication effects in North Atlantic coastal ecosystems (scientific article)

Relative impacts of fishing and eutrophication on coastal fish assessed by comparing a no-take area with an environmental gradient (scientific article)

A spatial regime shift from predator to prey dominance in a large coastal ecosystem (scientific article)

 

Evaluated no-take zones

Map

Storjungfrun -Kalvhararna

The no-take zone at Storjungfrun and Kalvhararna, in the county of Gävleborg was established in 2011 in order to protect the declining stocks of whitefish. The no-take zone covered an area of 147 km2, and is surrounded by a large 4000 km2 buffer zone in which whitefish is protected during spawning. The no-take zone was reopened to fishing in 2016 and fish populations are currently only protected during spawning season.

Short summary of results:

  • Adult whitefish populations rapidly increased in the no-take zone and spawning closure compared to the areas open to fishing. The increase was largest in the no-take zone.

  • Sea trout abundance also increased after the establishment of the no-take zone.

  • Commercial landings of whitefish increased in the Bothnian Sea after the establishment of the protected areas.

  • After the no-take zone was reopened to fishing, the abundance of whitefish decreased to levels similar to that before fishing was prohibited. This shows that the positive effects of no-take zones rapidly disappear if fishing regulations are removed. 

More info

Chapter 6 (page 52) "No-take zone for whitefish in the Bothnian Sea" i Aqua reports 2022:20

Rapid effects of a fishing closure on whitefish (Coregonus
maraena) in the northern Baltic Sea (scientific article)

Benefits and costs of two temporary no-take zones (scientific article)

 

 

 

 

Gålö (Lännåkersviken)

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" i Aqua report 2022:20

Benefits and costs of two temporary no-take zones (scientific article)

Social Acceptability of Marine Protected Areas – A Case Study of the Gålö No-Fishing Zone in Sweden (master essay)

 

 

Licknevarpefjärden

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" i Aqua report 2022:20

Relative impacts of fishing and eutrophication on coastal fish assessed by comparing a no-take area with an environmental gradient (scientific article)

 

 

Gotska Sandön

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" i Aqua reports 2022:20

Effects of a large northern European no-take zone on flatfish populations (scientific article)

 

 

South Kattegatt

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" i Aqua reports 2022:20

A no-take zone and partially protected areas are not enough to save the Kattegat cod, but enhance biomass and abundance of the local fish assemblage (scientific article)

Effects of chronic bottom trawling on soft-seafloor macrofauna in the Kattegat (scientific article)

 

 

Vinga

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" i Aqua reports 2022:20

Rapid re-establishment of top-down control at a no-take artificial reef (scientific article)

 

 

 

Havstensfjorden

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" i Aqua reports 2022:20

Local cod (Gadus morhua) revealed by egg surveys and population genetic analysis after longstanding depletion on the Swedish Skagerrak coast (scientific article)

 

 

Kåvra

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" i Aqua reports 2022:20

European lobster subpopulations from limited adult movements and larval retention (scientific article)

Long-term decrease in sex-specific natural mortality of European lobster within a marine protected area (scientific article)

 

 

Effects of spawning closures

Spawning closures, i.e., areas closed to fishing during spawning season, are often used as a management tool in coastal fisheries. Knowledge on the effects of spawning closures on fish are, however, more limited than that of no-take zones. A large study within the project Refisk has evaluated the effects of spawning closures on perch and pike. Spawning closures were found to benefit pike, but not perch. Effects on the food-web structure were also found.

There are a large number of spawning closures by river outlets along the east and west coast of Sweden where both sea trout and salmon spawn. An assessment at some of them found strong positive effects of the closures on trout and salmon parr abundances in the rivers.


Contact

Ulf Bergström, Researcher
Department of Aquatic Resources, Institute of Coastal Research, SLU
ulf.bergstrom@slu.se, +46 10 478 41 17

Mattias Sköld, Researcher
Department of Aquatic Resources, Institute of Marine Research, SLU
Ship Management Unit, SLU
mattias.skold@slu.se, +46 (0)10 478 40 46, +46 (0)705-37 87 74

Charlotte Berkström, Researcher
Department of Aquatic Resources, Institute of Coastal Research, SLU
charlotte.berkstrom@slu.se, +46 10 478 41 65