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