70 years of helping people to care for our ocean

The 86th iSimangaliso surf-zone fish monitoring and tagging field trip

By Dr Bruce Mann

The 86th iSimangaliso surf-zone fish monitoring and tagging field trip was conducted at Sodwana Bay from 9-11 February 2021. Weather conditions were near perfect on the first two days (Tuesday and Wednesday), but the swell increased to over 4 m on Thursday and by Friday it was unfishable (and undriveable) with a huge swell, strong wind and driving rain. We therefore unfortunately had to call the trip off a day early. The swell ranged from about 1 m on the first two days to over 4 m and the water temperature was a very warm 28ºC. Due to the COVID-19 pandemic, we dropped the size of the team to six anglers to ensure adequate social distancing. The team included Arthur Mann, Ralph Riggien, Kevin Rudolph, James Turner and team leaders Rob Kyle and me.

During the trip, we caught a total of 157 fish of which 115 were tagged and 42 were small fish or non-tagging species. Unfortunately, for the first time in many years we did not get any recaptures. This was mainly because of the warm, clean, calm conditions and lack of reef fish. However, excitingly we did manage to tag eight giant sandsharks and three honeycomb stingrays with acoustic tags as part of our involvement with the Acoustic Tracking Array Platform (ATAP) hosted by the South African Institute for Aquatic Biodiversity (SAIAB).

With the clean, calm conditions, daytime fishing was relatively slow, but the fish turned on after dark with the big flatfish providing some very exciting fishing!

A total of 79 fish (50.3%) were caught in the two exploited areas (EC & ED), while 78 fish (49.7%) were caught in one of the no-take wilderness areas (SD). With the trip being cut short, we were not able to fish the second day in the wilderness area (SC). In terms of catch rate, the CPUE in the exploited areas was only half (0.6 fish/angler/hour) compared to that achieved in the no-take wilderness area (1.12 fish/angler/hour). This difference was mainly driven by the high number of largespotted pompano caught in the wilderness area (SD) on the first day. A comparison between the catch-and-release area (EC – Adlams to Red Sands) and the controlled area (ED – Jesser Point to Adlams), showed very little difference in catch rates (i.e. 0.59 compared to 0.61 fish/angler/hour). This similarity is not unexpected and is largely due to the fact that local fishermen are fishing along the entire length of this coastline and there is very little observed compliance with the new catch-and-release zonation.

A total of 24 fish species were recorded on the trip with 22 species caught in the exploited areas and 12 species caught in the no-take wilderness area. No new species were recorded, so the total species count for the project remains at 116 species to date. However, the crocodile needlefish caught by Arthur and the pickhandle barracuda caught by James were fairly rare catches. Species composition was dominated by largespotted pompano (62), grey grunter (18), cave bass (9), bonefish (8) and giant sandsharks (8) amongst others. The lack of reef fish such as speckled snapper was largely due to the warm, clean conditions. A midday snorkel on the reef off Kingfish Bay 2 revealed a spectacular variety and abundance of reef fish but they were clearly not feeding.

Some incredible fish were caught during the trip including three magnificent giant kingfish of 1040 mm FL (21.9 kg), 980 mm FL (18.3 kg) and 720 mm FL (7.4 kg) caught by Rob, Kevin and myself respectively. Then a shoal of no less than eight giant sandsharks and three big honeycomb stingrays were shared between the team, the biggest being a honeycomb of 1300 mm DW (57.4 kg) caught by James and a sandshark of 1550 mm TL (20.9 kg) caught by myself. Rob also caught a huge Jenkins stingray of 1360 mm DW (~66 kg) which gave him a real tussle. Although few and far between, Rob and I both caught big speckled snappers of 580 (4.4 kg) and 590 mm FL (4.7 kg) respectively. Please check out our new Fish App (Marine Fish Guide for Southern Africa for both Android and iPhone) for easy access to information on linefish, including a length/weight calculator https://www.saambr.org.za/marine-fish-guide-for-southern-africa-app/.

Apart from the great fishing and an incredible snorkel, one of the highlights of the trip for me was seeing Greg Nanni and Richard Penn Sawers fly past doing a surveillance flight in the Ezemvelo KZN Wildlife Cessna. It was great to see this aircraft back in the sky doing important work!

I would like to thank SAAMBR, the iSimangaliso Wetland Park Authority and Ezemvelo KwaZulu-Natal Wildlife for providing funds and logistic support for this long-term monitoring project. Thanks to Sifiso Vumase for sorting out gate access and other logistics. We are grateful to Ford Wildlife for the sponsorship of their impressive vehicle. I would also like to express my sincere gratitude to the members of the voluntary tagging team for their hard work and on-going commitment to this exciting project.