Our director of research, Dr Enrico Gennari, writes about the changes to white shark populations along the Western Cape, and the disappearance of the species in some of the white shark hotspots of South Africa.
Fact: False Bay, home of the famous flying white sharks of Air Jaws, has not had a reliable white shark season for at least 2-3 years.
Fact: Gansbaai, the White Shark Capital of the world, has cage dived with far more bronze whaler sharks than white sharks for the last 2 years.
Question: can it all be because of a couple of orcas which, by the way, have been seen roaming from Namibia all the way to Port Elizabeth quite regularly?
I personally believe orcas are playing a role, in particular in Gansbaai, but then why not so much in Mossel Bay and Plettenberg Bay?
What is going on?
In the last few years, climate changes are unfolding in our oceans; orcas are roaming more and more in Southern Africa’s coastal waters; the distribution of small pelagic fish, such as sardines and anchovies, is shifting east to west and vice versa, at least in the last few decades etc… What does all this have in common? The fact that we can’t do too much about it as a single nation.
However, in the last 5-6 years (at least) an experimental small fishery has been given the go ahead by the Department of Agriculture Forestry and Fishery (DAFF): the demersal shark longline industry.
Why do I call it experimental?
Because it did not go through any EIA process or even a proper study before being approved. I was once told by a high ranking DAFF official that proving the impact of this fishery is up to non-government researchers and the lack of such a study is not reason enough to prevent an industry to develop. Even though I don’t like that statement, I could agree with it ONLY IF there were checks and balances in place to make sure, as we go ahead, that the impact doesn’t exceed the advantages.
A recent article on pelagic shark longline industry, published in PeerJ by Gareth Jordaan of the Oceanographic Research Institute in Durban (https://peerj.com/articles/5726/), outlined that one of the main issues, if not the biggest, in evaluating the impact of such fishery was the inconsistency in reporting, as to what is landed at a port and what is caught on a boat are usually quite different.
To my delight, I was told that one of the main permit conditions of the demersal shark longline fishery is to have independent observers on board for proper control of the industry. “Great!” I said. However unfortunately, since the inception, there has not been a single observer on those boats.
Is the lack of observers a real issue?
Without independent observers, we need to trust that what the fishing companies declare in their landings at harbour is their true catch.
Do you think SARS (IRS or similar) would trust that what a rich company declares, is what it really makes? Sometimes yes, but now and then SARS would have to do some checking.
However in this case, there isn’t such control, and we must trust those fishing companies. From a research, management and conservation point of view, we know catches and landings are always different: not just because the fishing companies might lie, but also, and sometimes even more importantly, because of what is called by-catch.
So what is by-catch?
Every time a boat goes fishing targeting specific species, different species are also caught: animals that were not targeted. They are then thrown back into the water, sometimes highly stressed but still alive, yet more often already dead. In the case of unsupervised baited longlines, a shark caught would fight for hours and eventually (often after only 15-20 minutes, in the case of hammerhead sharks) reach an unmanageable stress level which leads to its death. Thus few animals live whilst many dead ones are often thrown back into the water. Those thrown back are not part of the counts related to that day’s fishing. This is UNLESS you have an independent observer on that boat which can include those animals into the count.
So this industry, even though well regulated by permit conditions (which include areas where they cannot fish in), is unfortunately not managed at all. DAFF states there is not enough money to pay for the observers, which is fair as we are a developing country. However, since this kind of fishing is a commercial avenue, why not have the fishing companies pay for the administration and support of observers, although managed independently? Of course, the companies will protest, but then DAFF could explain to them that it is in their long-term interest. The presence of observers will mean DAFF scientists would have much better data about the real catches, thus they can manage better quotas, restrictions or even shift target species to more sustainable ones. In return, this would mean those fishing companies will be able to carry on their business for decades to come.
Long-term advantage VS quick bucks yet unsustainable, and thus less remunerative in the long-term, easy choice isn’t it?
Everyone would win, but then why is it so difficult?
Other fisheries (even larger than this one) have observers on boats. Observers are not needed on board all the time on every ship. Something that science is getting better at is obtaining data from small sample sizes (few observers every now and then) and being able to extrapolate this to a larger situation (inferring catch data almost as if observers were on board all the time).
Can we monitor what really is caught, whether protected species are not caught (intentionally or accidentally), and whether the areas of operations are the ones allowed by the permit conditions?
So why isn’t there such political will?
You might have an answer and it would be as good as mine, thus I leave it up to anyone to form their own ideas.
So going back to the geographical shift of white sharks, the demersal shark longline industry has been operating along the SA coastline for the last few years. It does target (again keep in mind the difference between targeting and catching) several species of sharks including soupfin, bronze whaler and smooth-hound sharks. These sharks are an integral part of the white shark’s diet. There is data (unpublished) showing the collapse of soupfin and smooth-hound shark populations in the Western Cape. WWF’s SASSI has put these species in their RED category and considers these fisheries to be unsustainable.
So why do these species remain the top target species for the demersal shark longline fishery authorised by DAFF?
Ask any recreational angler how difficult it is to catch these sharks, even professional anglers. Many national competitions rely almost entirely on sand sharks nowadays. These species are disappearing under our very eyes. When a top predator faces the disappearance of some of its main prey items, it is naturally forced to move where those items are more abundant, thus a shift in the geographical distribution.
Isn’t this what we are seeing, west to east?
A collaborative effort led by colleagues of the Dyer Island Conservation Trust in Gansbaai has recently submitted an article in relation to the impact orcas are having on white sharks in that area. We, at Oceans Research, provided the data related to the contemporary presence/absence of white sharks in Mossel Bay. It seems quite clear there is definitely a shift from Cape Town and Gansbaai toward Mossel Bay and Plettenberg Bay.
Can I pinpoint the reason to be either orcas or longliners?
Neither! Causation is one of the most difficult things to prove in science. I could easily say something such as the trend in white shark presence is dropping at the exact same rate as the increase in orca sightings or longlining effort, but I cannot prove it, one is the cause of the other, as there could be more causes or more complex relationships.
However my question is: do we really need to prove it? Or is the doubt enough to maybe put a few observers on those 5-6 boats?
Yes 5-6 is the number of boats which make that industry. How can 5-6 boats have such a large impact on the entire country and on so many different species? I’ll just give you an anecdote: a researcher friend of mine externally tagged 30 smooth-hound sharks with spaghetti tags in Port Elizabeth a couple of years ago. Within one month, only, 27 of those 30 were caught by only one single longline boat (90%). Extrapolate that ratio to 5-6 boats that constantly roam our coastline and you will see that, within a few years, one could easily see an impact and within even a decade or two, those 5-6 boats specifically targeting sharks could remove all coastal sharks along the once-rich-in-shark-biodiversity South African coast.
Earlier this year I was invited to a meeting organised by the Department of Environmental Affairs (DEA) in Cape Town to discuss plans to maintain the incredible shark biodiversity South Africa has. There were around 20-30 people, almost all specialists and scientists working on sharks. Usually, it is very difficult to agree about anything at these types of meetings, yet we all agreed the demersal shark longline industry could represent the number ONE threat to the conservation of sharks in South Africa. That is a strong statement. We are now waiting for a follow up meeting that DEA agreed to organise, asking DAFF managers to be part of the discussion.
Nevertheless, I want to be clear: nobody is a priori against DAFF. Nobody is a priori against fishing. We would like to be able to discuss and support DAFF in their difficult task to find a balance between supporting our economy while protecting the natural resources South Africa has. I personally believe shark fishing can be sustainable if managed where target species are decided based on data, and if, and only if, there is a serious monitoring system. But if we can’t have that, I would like to see DAFF using a precautionary approach.
I was ecstatic when, as a young researcher in Italy, I found out that South Africa was the first country in the world to adopt a precautionary approach when it declared the white shark protected. They did not have a great deal of data at that stage on the status of the white shark population in South Africa. However they realised it was an incredible resource in terms of tourism, job creation and overall economy, plus the obvious importance of protecting a top predator from an ecological point of view. Thinking ahead was worth it and not waiting until it might be too late.
Thus why can’t DAFF put their minds in the same pro-active framework?
Let’s have a deeper look into it, by comparing the demersal shark longline industry with the white shark cage diving industry (as an example of ecotourism, a non-consumptive utilisation of the natural resources)
- Does the demersal shark longline industry, as it is run and managed at the moment, make sense from an ecological point of view? NO, as already discussed earlier.
- Does the industry make sense in terms of supporting South Africa’s food security? NO, as all products are exported mainly to Australia to be sold as fish ‘n’ chips.
- Does it make sense in terms of job creation? Those 5-6 companies employ maybe 200 people? That is nothing compared to the thousands if not millions of South African people who benefit from shark ecotourism. And I am not just talking about the rich owners of cage diving companies but also the people employed in the hospitality industry, which greatly benefit from such forms of tourism.
- Similarly, the few million Rand per year contribution of the longline industry to the South Africa’s economy, pales in comparison to the 20 Billion Rand per year overall contribution of shark ecotourism.
So why does this industry exist in its present form?
Excuse me Dr Enrico Gennari, are you suggesting to close down that industry?
No. What I would like is for DAFF to apply its mind, maybe accepting help from outside, and at least enforce the good regulations they have already put in place.
What I would like is to have a sustainable fishing industry that benefits long term, without putting entire ecosystems at risk.
If DAFF is not willing to apply such logic, then I would rather use a precautionary approach, as DEA did with white sharks in the past, and work with those fishing companies to identify alternative businesses to keep employing the people they have and making a more long-term sustainable business, for their own good to.
That is exactly what DAFF actually did around 10 years ago in regard to the offshore shark longline industry: it set up stricter regulations, observers on board, and pushed an effort toward transformation of that industry when permits for shark-directed longliners were abolished in 2005, and formerly shark-directed vessels were allocated permits to catch swordfish and tuna, within a stricter regulatory framework (Da Silva et al., 2015: a study led by DAFF researchers). This sounds in completely the opposite direction with the demersal shark longline industry.
Why this industry is treated differently than the much larger and more complex offshore sister fishery?
Often scientists are blamed not to take a stand unless we are 100% certain of the interpretation of our data. However, I am at a point where I feel we can’t afford to wait to be sure. We can’t afford to risk losing South Africa’s coastal shark biodiversity.
I’d rather risk my professional reputation, and give my personal opinion, which I cannot prove with strong p-values and pretty graphs, but I can support with a simple notion: this time, we can’t afford to be right 100%, as that certainty will come too late.
We need to keep in mind, nature is not ours, but we are borrowing it from future generations!
Photo credit: Chris Fallows