BALANCING ACT

[Originally published in the May 2024 issue of SKI-BOAT magazine]

By Bruce Mann
(Senior scientist recently retired from the Oceanographic Research Institute in Durban)

FOLLOWING several recent enquiries from the SADSAA environmental officers, I decided to share my understanding, after many years of experience, of the processes used to manage our linefish species in South Africa. Hopefully this will help ski-boat anglers to better understand and support the fishing regulations.

STEP 1
RESEARCH AND MONITORING
To understand the status of a particular linefish species, it is necessary to conduct research on that species. This may include a range of different aspects including life history studies (e.g. feeding biology, age and growth, reproduction, distribution, habitat preferences), movement studies (e.g. tagging, acoustic telemetry), monitoring of catch and effort, and fish length frequencies etc.
This stage is aimed at trying to understand each fish species in as much detail as possible.

STEP 2
STOCK ASSESSMENT
Once sufficient information has been collected on a particular species, a stock assessment can be conducted to determine the stock status (how many fish there are now) relative to its theoretical pristine or unfished level (how many fish there were before fishing started).
There are several different ways of doing stock assessments depending on the type and quality of data available. In South Africa, many of the earlier stock assessments were conducted using yield-per-recruit and spawner biomass-per-recruit models. More recently, where sufficient catch and effort data exists (mainly from the commercial linefishery), these models have largely been replaced by age-based surplus production models. These are relatively complex mathematical models that require considerable training to understand and operate.
Basically, these models tell us is much fish can be caught without depleting the stock.
Of course, they are only as good as the quality of data fed into them, and all models make certain assumptions which need to be well-informed.

STEP 3
MANAGEMENT OPTIONS
Once the status of a particular stock has been assessed, recommendations are made on how best to manage that stock to ensure its future sustainable use.
In South Africa, a Linefish Management Protocol (LMP) was developed in the late 1990s to help guide this process. A simple framework was developed to categorise the stock status of a species or population. If a stock is above 50% of its unfished level it is considered to be underexploited; if it’s between 40- and 50% it is optimally exploited; if between 25- and 40% it is considered overexploited; and if the stock is less than 25% of its unfished level it is considered to have collapsed.
Based on these categories, different management actions can be recommended. For example, in the case of underexploited stocks, more fishing and harvesting can be allowed. Optimally exploited stocks are at their desired or target level where production is at its maximum (sometimes called maximum sustainable yield) and current fishing effort and harvest should be maintained. For overexploited stocks, management intervention is required to rebuild stocks to their optimal level. In the case of collapsed stocks, drastic management intervention is required to protect the stock and enable stock recovery.
In the multi-species, multi-user South African linefishery, fishery managers only have a limited number of tools in their toolbox to assist them. Basically, these consist of size limits, bag limits, seasonal closures, closed areas (also known as marine protected areas or MPAs), effort limitations, gear restrictions and moratoria (fishing bans). To better understand each one of these management options, I will briefly go through them individually.

Size limits
The most common application of this option in South Africa is the use of minimum size limits. This is normally set at a size at which 50% of the fish population is mature, thus providing some fish with the opportunity to spawn before they are available to be caught in the fishery. It also protects the fish when they are growing at their fastest rate, as growth slows down after reaching maturity.
Another application could be maximum size limits to protect larger breeding fish, or a combination of the two (called slot limits) which allows harvesting of fish above a minimum size and below a maximum size to optimise both growth and reproduction.

Bag limits
In South Africa daily bag limits are used to limit an angler to a certain number of fish per person per day. While this regulation may limit fishing mortality (i.e. the number of fish killed by fishing), it also serves to enable a fair allocation of fish between large numbers of anglers.

Closed seasons:
These are times of the year that are closed to fishing for certain species. These are normally set when a fish species becomes particularly vulnerable to fishing pressure. Most often this coincides with the breeding season of a species as many fish come together when they spawn. The closed season for red steenbras (1 October to 30 November) is an example.

Closed areas
These are specific areas that are closed to fishing for one or more species. In South Africa, these areas generally fall into MPAs which may be zoned into controlled zones (fishing allowed), controlled pelagic linefish zones (only pelagic gamefish species may be caught), controlled catch and release zones (all fish caught must be released) and restricted or no-take zones where no fishing or extractive use is allowed.

Effort limitation
This involves limiting the number of rods, anglers, boats, etc. that are allowed to fish. This tool has been successfully used to reduce the number of commercial rights holders that are allowed to fish in different areas around the South African coast.
Gear limitation
This involves limiting the type of gear that is used for fishing. For example, in the South African linefishery a maximum of ten hooks may be used per line. The recent prohibition of using drones to fish is another example of gear limitation.

Moratoria
This is the most severe of all the management regulations and is normally only implemented as a last resort when other restrictions have proved unsuccessful, and the stock is below 5% of its unfished level.
The rule of thumb regarding moratoria is that they should be implemented for at least the half-life of the species being protected. For example, if the fish species can live for 20 years, it should be protected for at least ten years before the regulation is re-evaluated. However, as is the case with 74, once a moratorium has been implemented, it is very difficult to conduct a stock assessment as there is no catch and effort data on which to base such an assessment.
Normally a combination of the above-mentioned management options is implemented for each species to ensure its sustainable use.

STEP 4
IMPLEMENTATION OF REGULATIONS
Once a suite of management options is decided upon by the scientists and fishery managers and they have gone through the necessary public participation processes, these regulations are then gazetted into law under the Marine Living Resources Act (No. 18 of 1998).
However, it is interesting to note that, other than the moratorium for red steenbras which was introduced in 2012 and subsequently removed following court action, the last substantial changes made to the linefish regulations in South Africa were in April 2005! Ideally, fishing regulations should be regularly reviewed and updated as the status of fish stocks changes. This is called adaptive management.
Like so many other aspects of life in South Africa, implementation of the law is where most of the problems arise. We simply do not have the capacity or manpower to enforce the fishery regulations, and consequently there is large scale abuse and blatant disregard of the regulations.
I personally feel that this is where we as responsible anglers should step in and self-police ourselves. If the fishing regulations are justified and based on good science (which most of them are), we should take it upon ourselves to stick to the regulations and encourage our fellow anglers to do likewise. Ultimately, we all stand to benefit from better managed fisheries.

STEP 5
MONITORING AND RE-ASSESSMENT
This aspect completes the management cycle. It is here where regular monitoring of catch, fishing effort and length/size of fish caught is required. This information is vital to enable catch trends to be tracked over time and to allow scientists to plug the data into their computer models to assess the status of the fish stocks.
Unfortunately, we have largely failed to implement successful long-term catch and effort monitoring programmes in the South African marine recreational linefishery.
However, this is not through a lack of trying! Some of the older KZN ski-boat anglers will no doubt remember the catch cards introduced by Rudy van der Elst from ORI in the 1980s. This system was largely replaced by ski-boat inspections conducted by Natal Parks Board/Ezemvelo KZN Wildlife in the 1990s, which was then replaced by the boat launch register system implemented in the 2000s.
While all these systems had some merit, they were all plagued by various biases, the most common of which was the simple reluctance of anglers to complete them.
We all know the value of keeping good records for business management, understanding that without such information it is very difficult to determine how the business is doing. In the same way, we should be keeping good records of the time we spend fishing and the fish we catch.
Even if this was only done for fishing competitions (where such information is recorded anyway), it would go a long way in helping to inform more accurate stock assessments and ultimately better, more informed fishing regulations.
By law, commercial fishermen must complete a daily catch and effort register (commonly known as the “blue book”) which is captured onto the National Marine Linefish System (NMLS) database.
Currently, most of the stock assessments of linefish species caught in South African waters are based on commercial catch and effort statistics.
I sincerely hope that this article has helped to explain how fisheries management is supposed to be done in South Africa. As anglers, it is ultimately up to us to ensure that we use our linefish sustainably and responsibly.
I wish you all tight lines and remember: “Limit your catch, don’t catch your limit.”
For those who would like to have the current regulations available at the push of a button – along with more interesting information on our linefish species – please download the ORI Fish App “Marine Fish Guide for Southern Africa” available on Google Play Store or the App Store for only R200. The proceeds go to the ORI Cooperative Fish Tagging Project.