Why are MPAs Important?

You must be part of the Crew to get points for reading this. Please join the Crew >

point

Right banner spacer
At the moment, we protect far more of our land than we do the sea.
Globally, just over 3% of the ocean has some kind of protection, and less than 1% is ‘highly protected’ (i.e. closed to fishing)¹. In contrast, about 6%
of the worlds land surface is protected in National Parks and similar protected areas².

As we show in the new series of Fish Fight, fishing boats are spreading
over more and more of our oceans, developing new ways to catch fish,
and opening up markets for new species. Other industries like aggregate dredging, wind farms, and environmental pressures like pollution and ocean acidification are all putting pressure on our oceans. Marine Protected Areas (MPAs) are an important tool for getting the right balance between exploiting the oceans and keeping them healthy and productive.

Around the UK, we don’t do much better:

About 6% of UK waters are in MPAs³, but often there is little in the way of protection with no change made to the types of fishing and other activities that can take place in them.
Local fishing authorities also have byelaws that protect parts of their districts against certain types
of fishing. Our estimate is that well over 90% of UK waters are open to high-impact fishing methods like scallop dredging for all or part of the year⁴.
Only 0.001% of British seas are protected against
all fishing for nature conservation reasons⁵.
If they are all put in place, the 127 new Marine Conservation zones (MCZs) could take the ‘protected’ area in English waters up to 27.1%⁶. But the decisions about what level of protection each MCZ will have are yet to be made – so the area closed to damaging fishing methods could
be much less than this.

We’ve written a charter outlining what our Save Our Seas campaign is asking for, and why we believe it’s important:

The science of Marine Protected Areas

Reefs in Lyme Bay

MPAs can have a number of benefits, and there is evidence to support each of these aspects. Below, we've selected a few of the studies that are most relevant to the UK. It is also the case that studies on MPAs in the exact environmental and fishery conditions we have in the UK are rare, partly because we don't have very many MPAs in place to be studied. That's why we think it's essential that rigorous science is done inside and outside the new Marine Conservation Zones in England to look at the benefits and costs to fishermen.

(A wide-ranging and recent review of evidence for the benefits of closed areas for fish stock recovery can be found here.)

1. MPAs allow the seabed habitat to recover

When high-impact fishing methods like scallop dredging and bottom-trawling are excluded from an area, the seabed can recover the three-dimensional habitat that
it would often have had before trawling began. That's obviously good news if you are a seabed-dwelling sponge or coral. But it's also good news for fish species that thrive on a complex, healthy seabed. For a young fish, a rich seabed means more places to find food, and more places to hide from the creatures that want to eat them.

Lyme Bay is a large bay in Southern England, between Weymouth in Dorset and Torbay in Devon. In 2008, a 60 square mile area was closed to boats using mobile fishing gear, like trawl nets and scallop dredging. Lyme Bay contains many rich reefs, which are vulnerable to damage from these types of fishing. 5 years of video survey work has shown how the reefs in Lyme Bay, and the areas of seabed between the reefs, are recovering. This work is featured in episode 3 of 'Hugh's Fish Fight: Save Our Seas'.

The Inshore Potting Agreement in South Devon has meant that an area of sea has been voluntarily closed to trawling and dredging since for over 30 years.

Studies have shown that some fish species are larger inside the protected area, which scientists have linked to improvements in the seabed habitat and seabed species that fish rely on⁷.

2. Improve the lives of local, small-scale fishermen

MPAs where low-impact fishing is allowed to continue can improve the lives of local, small-scale fishermen. Small-scale fishermen make up 77% of the UK fleet. They usually use lower-impact methods of fishing like static nets and pots. And they tend to work closer to their home ports, because they can't spend so long at sea. Boats that use high-impact methods like scallop dredging and trawling tend to be larger and travel further from their home ports in search of fishing grounds. That can bring fishermen into conflict over where they are fishing and the effect they may be having on the seabed.

In Lyme Bay the benefits of closing an area to bottom-trawling are being seen by the local fishermen. Small boats from harbours like Lyme Regis and West Bay say they are getting better catches, and seeing fish species that they haven't seen for years, or sometimes ever before. And they no longer have to worry about a trawler damaging their static fishing gear when it is left out overnight.

The Lyme Bay fishermen also acknowledge that excluding the trawlers caused some problems, and that more static fishing gear was being put out than was likely to
be sustainable. Working with the Blue Marine Foundation, many of them have now signed up to a voluntary code of conduct
limiting the amount of fishing gear they will use, and are working closely with
Plymouth University to study the sustainability of their fishery.

Bridlington in East Yorkshire is home to Europe's biggest lobster fishery, and byelaws there have protected inshore fishing grounds from mobile fishing gears. Rich fishing grounds further from shore are beyond the reach of byelaws, and fishermen there have suffered damage to their gear by large scallop dredging boats. These fishing grounds have been proposed as one of the new 127 Marine Conservation Zones, but has not been forward for protection in 2013 by the government.

3. MPAs can protect the spawning or nursery areas of fish

Fish often like to use certain areas of the sea or seabed to spawn, and young fish often hang out in different areas to adults: because they may prefer a different type of habitat or food. It makes obvious sense to protect these areas and these fish from fishing to ensure the next generation of fish can grow to a catchable size.

We already have several such MPAs around the UK: the Plaice Box in the southeastern North Sea, the Mackerel Box off the southwestern UK and the Norway Pout box off the north of Scotland. And amongst the proposed new Marine Conservation Zones, there are sites like Kingmere in Sussex, which will protect a nesting area for black bream.

Sometimes, temporary MPAs are the right tool to protect fish at a particular life-stage. Temporary 'real-time closures' are used in the North Sea to protect juvenile cod, haddock, whiting and coley when they are discovered in high numbers.And to protect concentrations of adult cod, there are numerous real-time closures in the North Sea every year: if a high proportion of cod start being caught in an area,
it is quickly shut to fishing boats for 3 weeks.

4. MPAs build up populations of fish, which can breed better because they reach a bigger size

This one's fairly easy to grasp: if an area is protected from fishing, the fish that would otherwise have been caught are more likely to reach a ripe age and breed more generations of offspring. Scientists talk about BOFFs: 'big old fat females'. Bigger females can producer more eggs over a longer spawning season. And they produce bigger eggs that hatch into bigger fish, which are more likely to survive.
In cod, 'experienced spawners' may produce over ten times more offspring that will survive to their first birthday⁸.
To look at this effect of MPAs, a 2009 study combined the results from 124 reserves
in 29 countries. They found that fish averaged a 350% increase in biomass and
200% increase in density inside the MPAs. MPAs in temperate waters
(like we have in the UK) worked just as well as those in warmer waters⁹.

Isle of Man Scallops On Georges Bank, off the north-east USA, a large area was closed to trawling in the early 1990s, in response to the crash of the cod stocks there. After 6 years, with line fishing still permitted, the stocks of yellowtail flounder, haddock and cod had increased by 800%, 400% and 50% respectively¹⁰.

A study of an area near Whitby where trawling is prohibited, found some signs that the protection was having a positive effect on fish species: finding species that were not found outside the MPA, and bigger and more abundant fish of several species¹¹.

5. Fish and shellfish move out of the MPA and can be caught outside it: the ‘spillover’ effect

Fish and shellfish can cross the boundaries of an MPA for various reasons, and once outside they can be caught by fishermen. This is the ‘spillover effect’, and Hugh saw it in action in the Philippines when filming for Fish Fight.
In the UK, an area next to the island of Lundy, in the Bristol Channel, has been totally closed to fishing since 2003. After four years, lobsters of a size that could be caught were five times more abundant within the no-take zone, than areas outside. And there was evidence of spillover of young lobsters from the MPA to adjacent areas¹².

A recent study of small MPAs in Norway found that after 4 years of protection, lobster catches increased by 87% per unit effort in areas outside but close to the MPAs¹³.

6. Eggs and larvae are exported out of the MPA to surrounding areas

In many species, eggs and very young larval offspring drift on currents and tides. So although they begin life inside an MPA, they may well grow up outside it, where fishermen are free to catch them.

In the Isle of Man, an area called Port Erin has been closed to scallop dredging and bottom trawling for 24 years, and now has dense populations of big scallops. These scallops can produce 12 times more offspring than areas outside because (a) there's more scallops, (b) they are older, larger, and producer more eggs, and (c) when scallops are closer to each other they breed more successfully. As a result, the areas surrounding the MPA have 5 to 10 times as many young scallops compared to the seabed further away⁸. Watch episode one of 'Hugh's Fish Fight: Save Our Seas' to see Hugh diving inside this MPA in the Isle of Man!