Fish Surveys in Exploited and Protected Areas of the Pondoland Marine Protected Area with Consideration of the Impact of the Mpa on Coastal Fisheries
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FISH SURVEYS IN EXPLOITED AND PROTECTED AREAS OF THE PONDOLAND MARINE PROTECTED AREA WITH CONSIDERATION OF THE IMPACT OF THE MPA ON COASTAL FISHERIES by JADE QUINTON MAGGS A dissertation submitted in fulfilment of the academic requirements for the degree of MASTER OF SCIENCE in the School of Biological & Conservation Sciences, University of KwaZulu-Natal, Durban. Oceanographic Research Institute JANUARY 2011 ii ABSTRACT ______________________________________________________________________________ The line-fishery in KwaZulu-Natal, on the east coast of South Africa, experienced a rapid decline during the 20 th century. The stocks of some important fishery species collapsed due to over-fishing, which led to the Minister of Environmental Affairs and Tourism declaring a state of emergency in the line-fishery in 2000. More restrictive regulations were implemented and the importance of marine protected areas became recognised. In June 2004, 80 km of the Pondoland coast was declared a multiple-use marine protected area. This coastline is a zone of transition between the Natal and Agulhas biogeographic regions and had been identified as a critical gap in South Africa’s marine protected area network. Part of the protected area is a 40x10 km no-take area, which is closed to offshore exploitation. The primary objectives of the closure, as gazetted, are the conservation of biodiversity and the rebuilding of commercially important line-fish stocks, which have been depleted by over-fishing. Not mentioned in the legislation, but of significant importance is the benefit of the Pondoland Marine Protected Area to nearby fisheries through the export of fish biomass. Between 2006 and 2010, experiments were conducted to evaluate the outcome of the fishery closure. The state of previously exploited line-fish species was assessed by means of a controlled fishing experiment where the abundance and biomass of key line-fish in the Pondoland no-take area were compared to that in the adjacent fished area. Some of South Africa’s most important line-fish species, which have been over-fished in the past, were significantly more abundant and larger in the no-take area. Slinger Chrysoblephus puniceus is a small sparid, which is heavily fished in KwaZulu- Natal where it accounts for 60% of the commercial line-fish catch. During this study and in the absence of fishing in the no-take area, this species increased in number and body size. Scotsman Polysteganus praeorbitalis is a larger piscivorous sparid, highly esteemed by the ski-boat fishery in KZN. The stock status of this species was reported to have collapsed due to over-fishing, but in the no-take area, scotsman was significantly more abundant and of a larger mean size. An increase in the mean size of this species was also recorded during the four years of study. With an increase in the number and size of previously depleted carnivorous line-fish in the no-take area, it is anticipated that the wider fish community may be indirectly affected through competition or predation. An underwater visual census was used to obtain a wider perspective of the fish community than was possible with line-fishing which limits sampling to line-fish species. The fish iii community in the Pondoland no-take area was notably different from that in the adjacent exploited area, but it was difficult to attribute this conclusively to protection from fishing. Most important was the dominance of large carnivorous species in the no-take area, in direct contrast to the abundance of small planktivores in the exploited area. This suggested a healthy predator-dominated community following protection from fishing in the no-take area. The potential benefit of the Pondoland Marine Protected Area on nearby fisheries was investigated by means of a tag-recapture experiment, which assessed fish movement within and between the no- take area and the adjacent exploited area. Tag-recapture observations indicated a great degree of site-fidelity (station-keeping) with an element of nomadic behaviour (ranging). Ninety percent of recaptured fishes were within 250 m of the original release-site, suggesting vulnerability to over- fishing. This study also presents some of the first known estimates of home-range size in certain species. Besides station-keeping behaviour, some fishes undertook ranging movements, between 150 and 1059 km from their release-site, making them available to adjacent fisheries. This distinction in movement behaviour was noted in the sparids, scotsman and slinger, as well as in the serranids, yellowbelly rockcod Epinephelus marginatus and catface rockcod E. andersoni . However, no ranging movements were recorded amongst poenskop Cymatoceps nasutus (Sparidae), halfmoon rockcod E. rivulatus (Serranidae) or Natal seacatfish Galeichthys trowi (Ariidae), all of which were tagged in this study. Finally, some recommendations for future long-term monitoring and management of the Pondoland Marine Protected Area are discussed along with suggestions for future research. iv PREFACE The experimental work described in this dissertation was carried out in the School of Biological & Conservation Sciences, University of KwaZulu-Natal, Durban, from January 2009 to December 2010, under the supervision of Mr Bruce Q. Mann, Prof Rudy van der Elst (Oceanographic Research Institute) and Dr Paul D. Cowley (South African Institute for Aquatic Biodiversity). These studies represent original work by the author and have not otherwise been submitted in any form for any degree or diploma to any tertiary institution. Where use has been made of the work of others it is duly acknowledged in the text. v DECLARATION 1 - PLAGIARISM I, ………………………………………………………………………………………. declare that 1. The research reported in this dissertation, except where otherwise indicated, is my original research. 2. This dissertation has not been submitted for any degree or examination at any other university. 3. This dissertation does not contain other persons’ data, pictures, graphs or other information, unless specifically acknowledged as being sourced from other persons. 4. This dissertation does not contain other persons' writing, unless specifically acknowledged as being sourced from other researchers. Where other written sources have been quoted, then: a. Their words have been re-written but the general information attributed to them has been referenced. b. Where their exact words have been used, then their writing has been placed in italics and inside quotation marks, and referenced. 5. This dissertation does not contain text, graphics or tables copied and pasted from the Internet, unless specifically acknowledged, and the source being detailed in the dissertation and in the References sections. Signed: ………………………………………………………… vi DECLARATION 2 - PUBLICATIONS Research presented in this dissertation has not yet contributed to any publications (in preparation, submitted, in press or published) other than those listed below: Popular article Maggs, J.Q. 2010. Marine Protected Areas. Ultimate Spearfishing 1 (2): 12-13. Signed: ………………………………………………………… vii They that go down to the sea in ships, that do business in great waters; these see the works of the Lord, and his wonders in the deep. - Psalm 107: 23-24 viii ACKNOWLEDGEMENTS __________________________________________________________________________________ To my supervisors, Mr Bruce Mann and Dr Paul Cowley, who edited my numerous drafts with painstaking attention to detail – thank you for your guidance and support. To Bruce, thank you for establishing this project, securing funding, organising field trips and providing me with the opportunity to analyse this data for my MSc. Paul, thank you for your encouragement and for travelling all the way from Grahamstown to come on a field trip – apologies again for the ‘barbel incident’. Thank you to Professor Rudy van der Elst for giving me the opportunity to complete this study while working at the Oceanographic Research Institute. The South African Association for Marine Biological Research, incorporating the Oceanographic Research Institute, is gratefully acknowledged for supporting me through this study and providing part of the funds. Thank you to the Director, Dr Marc Penning and Professor Michael Schleyer for providing on-going support to conduct this research. Thank you to my colleague and good friend, Dr Camilla Floros, for encouragement and help with multivariate statistical analysis. Thank you also to Mr Denis Rouillard for assisting with the preparation of maps. Mr Peter Watt-Pringle from Rhodes University and Dr Albrecht Götz from the South African Environmental Observation Network are thanked for assistance with generalised linear model analysis. Thank you to Eastern Cape Parks and Tourism Agency, the Wild Coast Project and the Department of Environmental Affairs for providing the majority of the funds for this research. Ezemvelo KwaZulu- Natal Wildlife kindly provided accommodation in the square-davel at Mpenjati. Mr George Nair and Mr Sam Ndlovu ensured that we always had a comfortable place to stay during field trips. Weekends at the square-davel always began with great anticipation as the team sat around the customary Friday night braai, hoping for good weather while listening intently to the distant roar of the Wild Coast. KwaZulu-Natal Sharks Board (KZNSB) kindly provided a fishing vessel and able skipper for every field trip. Thank you to Mr Mike Anderson-Reade for his unfailing support. The skippers who participated in field trips are gratefully acknowledged for giving