70 years of helping people to care for our ocean

91st iSimangaliso MPA surf-zone fish monitoring and tagging field trip

By : Bruce Mann 

The 91 st iSimangaliso MPA surf-zone fish monitoring and tagging field trip was conducted at Bhanga Nek near Kosi Bay from 26-29 April 2022. Unfortunately, the weather and sea state made angling difficult for the first three of the four days, with a big ground swell of over 2.5 m and strong south[1]westerly winds gusting up to 25 knots. Only on the last day did the swell drop to about 1.8 m and the wind switched direction to a fresh north-easterly. The water temperature was a pleasant 24°C.

The team included Simon Chater (SC), Arthur Mann (AM), Ewan Kyle (EK), Matt Furniss (MA) and guest anglers Russell Dixon (RD – my MSc student from Rhodes), and Murray Lewis (ML), who joined us all the way from Namibia. As usual, team leaders were Rob Kyle (RK) and me (BQ). The scouring of the points at Boteler Point and Rabbit Rock meant that we were unable to drive south along the beach for the first three days, so we walked the Rabbit Rock section on the first day and drove around the back to Dog Point on the next two days.

Fortunately, by the fourth day enough sand had accumulated to enable us to drive south from Bhanga. During the trip, we caught a total of 177 fish of which 88 were tagged and 89 were small fish or non[1]tagging species. Unfortunately, there were no recaptures caught during the trip. However, since our last trip to Bhanga in May 2021 we have had a largespot pompano recaptured by Nkanyiso, a local subsistence fisherman from the area. This fish was originally tagged by Scotty Kyle on 11 May 2021 at BNC62 and was recaptured on the 29 November 2021, probably in the same area.

We also had a speckled snapper tagged by Arthur at BNB25 on 14 May 2021 and recaptured by a local angler by the name of Simon on 16 March 2022, probably also in the same area. Interestingly, although Simon did not measure the fish, he claimed that he released it with its tag. Finally, we had another speckled snapper recaptured by subsistence fisherman Thabiso Mthembu, fishing near Kosi mouth on 30 August 2021. This fish was originally tagged by Rob at ED6 near Adlam’s Rocks south of Sodwana on 6 February 2019. It therefore moved a remarkable 77 km north during its 936 days (2.6 years) at liberty. It is encouraging to note that some local subsistence fishermen are reporting these recaptures to us even though there is no monetary reward for supplying this important information. Individual performance of anglers participating on the trip is shown in Table 1. Arthur took poll position, followed by Rob and me.

A total of 115 fish (65%) were caught in the three no-take areas (BNA, BNB & BND), while 62 fish (35%) were caught in the one controlled area (BNC). In terms of catch rates, the catch per unit effort (CPUE) in the three no-take areas (0.48 fish/angler/hour) was lower than that achieved in the one exploited area (0.68 fish/angler/hour). This is similar to previous results obtained at Kosi and is about half the catch rate achieved in other inshore areas of the iSimangaliso MPA. We believe that this is largely because there is no implementation of, or compliance with the inshore zonation of the MPA. To illustrate this point, we counted 19 shore fishermen fishing in the no take area between Castle Rock and Boteler Point (~8 km) on our drive home along the beach on Friday evening. Historically, local subsistence fishermen were always allowed to fish in the no-take area between Dog Point and Boteler Point and even though the legislation changed in August 2019, this has not been implemented in the area as it is extremely difficult to do so.

A total of 32 fish species were recorded on the trip with 12 species caught in the one exploited area and 30 species caught in the three no-take areas. One new species was recorded, namely a goldbar wrasse Thalassoma hebraicum, bringing the total for the project to 117 species to date. Species composition was dominated by largespot pompano (34), grey grunter (32), bigeye kingfish (23), speckled snapper (13), bonefish (9) and Natal stumpnose (8). It was encouraging to see the increased number of small, speckled snapper caught suggestive of good recruitment in the area. Several big fish were caught during the trip including two giant sandsharks of 1360 mm TL (14.1 kg) and 1320 mm TL (12.9 kg) both caught by Murray, and Rob got a sharpnose brown ray of 750 mm DW (12.9 kg). Matt got a lovely river snapper of 750 mm FL (6.0 kg) and Arthur got a good speckle of 535 mm FL (3.5 kg). Matt also got a beaut green jobfish of 840 mm FL (6.0 kg) and I got one of 810 mm FL (5.4 kg), with both fish coming off Dog Point. Rob got a nice blue emperor of 660 mm FL (5.3 kg) and Arthur got one of 585 (3.7 kg). Rob also got a bomber bonefish of 660 mm FL (4.2 kg) and a nice Harry hotlips of 560 mm FL (3.0 kg).

If you have not done so already, please check out our new ORI 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/. I would like to thank SAAMBR, the iSimangaliso Wetland Park Authority and Ezemvelo KwaZulu[1]Natal Wildlife for providing funding and logistic support for this long-term monitoring project. Thanks also to Zandile Kunene for arranging our accommodation at Bhanga Nek and to Max Stamatis from Adcan Marine for our bait. Finally, I would like to express my thanks to the whole team for your enthusiasm and perseverance. It was slow, tough fishing but you all persevered and caught some great fish!