“Peak Fish”. I heard the term for the first time the other day… And it resonated with me. The argument is that just as for oil, there is a peak amount of fish we can capture, and thereafter it must reduce. Unlike for oil however, global fish production has already peaked at 80 million tons in 1988. Since then it has steadily declined to around 65 million today. And this trend continues, despite significant increases in both commercial fishing boat numbers and fishing technology. But it needn’t be like this.
Consider this – When a given fish stock is un-fished, its population is largely determined by predator pressure and abundance of food. As the species comes under fishing pressure, breeding can in fact be stimulated. The reasons for this are complex, but one factor is the increase in available food. Young are not competing with so many adults for it, and so they mature quickly. Increased fishing results in increased yields, until you get to a point where the population is just maintained. This is called the maximum sustainable yield – we catch the largest volume of fish while ensuring the population remains steady.
The trouble today however is we have taken so many species beyond this point. We continue to take too many fish, we deploy poor fishing methods, and eventually the population collapses. In some cases this causes localised extinction where the species may never recover. You can see evidence of this in the image above. Global fish catch has reduced as we’ve pummelled one fish stock after another. The news however is not all bad. Fish stocks can and do recover – but it requires government with backbone to achieve it.
Consider the image for Norwegian Arctic Cod. Its population was decimated through the 40s and 50s, but since 2000 it has steadily improved, to where the fishery is now getting back to good health. Such recovery has been replicated in many other areas around the globe – but it doesn’t happen by chance, rather it is through fundamental changes in the way we fish. Following are key aspects contributing to it.
Ban High-Grading and Discard
Much of the World’s fisheries are covered by a quota system. Companies or individuals may catch a fixed tonnage of fish, called their quota. The maximum return they get for this is often for fish within a particular size range. Fish falling outside this range – that is they are too large or too small, result in lower profits. So the fishermen will discard them. This if often termed “high-grading” and it results in massive amounts of fish being thrown back dead. In some countries it remains legal, while in others it might be done covertly. Either way, proper fisheries management will see no high grading or target fish discard.
Active Quota Management
Fisheries agencies must actively manage their quota management system, and ensure the maximum sustainable yield, which can in fact vary with time, is never exceeded. Many countries set their quota based on limited scientific evidence, and then forget about it. This is a disaster waiting to happen. Fish stocks must be monitored continuously and quota adjusted over time. It is also critical for quotas of pelagic species – that is fish that travel great distances, be managed on a regional basis that recognises their migratory patterns across territorial borders.
Leaving Juvenile Fish behind
Many fishing techniques result in excessive juvenile take. One of the major causes is small mesh size in nets. Many countries still have no net size limit, or it remains too small. Larger mesh size allows smaller fish to escape and continue growing. Also fishing in spawning areas or those with high numbers of juvenile fish should be reduced or banned. Estuarine waters and mangroves are good examples of this.
Reduction of Bycatch
Bycatch is the taking of non-target species, and some fishing techniques are especially poor in this regard. Consider a trawl net that will capture all fish along its path that are above the net mesh-size. Bycatch in this case may include dolphin, turtles, seals, sharks, crustacean, molluscs, fin-fish and pelagic species. Such bycatch is normally thrown back dead – a total waste in anyone’s language. Better techniques can reduce or eliminate this waste. Turtle Exclusion Devices (TEDs) can stop turtles being captured in trawl nets. Spear fishing allows fisherman to take specific fish only. Some of you will laugh at this suggestion, but spear fishing remains a significant fishing method in many regions. Line fishing, by hand or longline may allow non-target species to be returned still alive. There are developments of new trawl nets that allow non-target fish to be returned alive. The key is to transition away from bycatch and towards more targeted fishing techniques.
Elimination of Destructive Fishing
There are some fishing methods that are so destructive there should be an outright ban on them altogether. Bottom trawling is one of them. Bycatch rates are massive, and may include ancient corals that will never be replaced. Fish Aggregation Devices (FADs) are another example. These are placed on the surface of deep water and attract all manner of aquatic species around them that are then mopped up by trawlers. They remain in use throughout the tropics. Then there is explosive fishing, which has become commonplace throughout the Coral Triangle. This kills virtually everything within the explosive blast range. While illegal, little is being done to curtail this activity.
Active Enforcement
Finally there is enforcement. Changing laws is often the easy part -It is the enforcement of said laws that is difficult. Governments all-too-often introduce well-meaning laws protecting marine ecosystem, but then overlook what it will take to enforce them. Much of our work today is assisting countries with their fisheries enforcement, and in many cases it is almost non-existent. That needs to change.
Summary
Fish remains a key protein source for mankind. Globally, 15% of our animal protein intake currently comes from it. Also, fish dominates protein intake in many impoverished areas such as West Africa and parts of Asia. We cannot just sit back and watch the continued collapse of global fish stocks. Stopping this however is not easy. It requires a fundamental change to fishing more sustainable methods, actively managing a robust quota system on an ongoing basis, and ensuring our fisheries enforcement is effective. If we did that the world over, then the future diversity of our oceans would be assured. If we don’t, well the world will increasingly squabble over ever-dwindling fish stocks, and we will hand our grandchildren oceans full of jellyfish…