How has fishing changed in Plett and Nature's Valley in the last 15 years?
Do fishermen really have an impact on the inshore fish species in our Bay?
In order to answer this question, the Nature’s Valley Trust (NVT) initiated a fisherman impact study in 2014 under our #ShareTheShores Coastal Impact Programme. Our initial study was conducted as part of a MSc thesis by Lisa Schroeter done through NVT and the University of Bremen. In order to determine if any changes have taken place in fishing effort and catch over time, these results were compared to results from another MSc thesis by King (2005) that evaluated the inshore linefishery in the greater Plettenberg Bay area in 2003/2004. Three sample areas were included (Nature’s Valley, Keurboomstrand: Enricos to Grootbank, and Plettenberg Bay: Eastern border of Robberg Nature Reserve to Keurbooms River mouth).
Lisa and the NVT team worked hard for 12 months, spending 1160 hours on beaches in the area and conducting 429 interviews with anglers.
Data collected in 2014 showed that the number of fisherman has decreased from 4 fisherman per km to 2 fisherman per km (per day) between the two study periods. The overall effort saw a decrease from 85 9789 angler hours to 47 125 angler hours per year during daylight hours. In Keurboomstrand there has been a 41% decrease in effort, while Nature’s Valley has seen a decrease of 27%. Interestingly, Nature’s Valley had the highest fishing effort of all the zones. The catch per unit effort (CPUE) which indicates relative abundance of fish has decreased by 60% in 2014/2015.
In 2003 it took a fisherman roughly 1.4 hours to catch a fish, now it is approximately just under 3.5 hours.
Focussing on the fish species caught, the mean size of blacktail (257mm) was significantly smaller compared to 2003 (291mm). The largest size class for strepie (299mm) and blacktail (449mm) was also smaller than in 2003 (349mm and 399mm respectively). Cape stumpnose and Elf also showed a similar trend with the mean size of each of these species decreasing from 235mm and 412mm to 200 and 385mm respectively. The mean size class of cape stumpnose showed no obvious peak in 2003, but a clear peak 200-249mm (Figure 1).
Figure 1. Size frequencies of three important fish species caught in Plettenberg Bay in 2003 and 2014.
Lisa’s project also looked at fishermen’s compliance for current rules and regulations. The data suggested that knowledge with fisherman with inadequate. While 76% and 80% of fisherman indicate they obey minimum size limits and bag limits respectively, 75% do not know the regulations when tested. This discrepancy can have dire consequences (Figure 2). For example, white steenbras has a minimum size limit regulation of 600mm and as a result of fisherman not knowing their regulations, 48.4% of all retained white steenbras recorded in 2014/2015 were undersize. Another species that showed similar results was Cape stumpnose with 27% of all fish kept by fisherman being undersize. The minimum size for Cape stumpnose is 200mm TL. Even though the majority of fishermen interviewed were in favour of the current fishing regulations, species specific knowledge of bag limits and size restrictions were poor. The positive spin off is that while the majority of fisherman lack knowledge of regulations, they feel they are obedient, and want to obey them.
Figure 2. The proportion of anglers that comply with current regulations vs. actual regulation knowledge.
In the 12 years between the two studies, fisherman now take longer to catch fish, fish are smaller and the species caught are less diverse.
Not surprisingly perhaps, this agrees fully with fisherman's perceptions on how fishing has changed during this time. All this suggests a resource base that is over-fished and that is being unsustainably fished. Arguments to blame trawlers, seals or ski-boat fisherman are sadly lacking thought - the species we catch as shore-based fisherman or not affected by those factors.
Due to this apparent lack in information, and to try promote more sustainable fishing in the region, NVT decided to produce fisherman’s resource packs with all the relevant fishery regulations for the most commonly caught shore based and ski-boast fish species in the Plettenberg Bay region. Other valuable materials that we have included were: a tape measure, what do to if you catch a tagged fish and a brochure with some marine debris and fishing regulation information. We started handing out these info packs in December the response to date has been fantastic so far! Keep an eye out for our #ShareTheShores team members who are handing the pack out, and continuing the important research and monitoring work in the area. Please help us by participating in our survey!
Special thanks to Table Mountain Fund, Hans Hoheisen Charitable Trust and Dulux Plettenberg Bay for sponsoring the packs, and to project partner the Plettenberg Bay Ski-Boat Club for distributing packs to ski-boat anglers.