fish surveys in exploited and protected areas of the pondoland marine protected area with ...

152 Pages·2011·4.86 MB·English

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
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ABSTRACT
______________________________________________________________________________

The line-fishery in KwaZulu-Natal, on the east coast of South Africa, experienced a rapid decline
during the 20th 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
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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.

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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.

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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: …………………………………………………………

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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: …………………………………………………………

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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

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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 up their hard-earned weekends to
take us fishing, which I gather was a fair trade.

To the many guest anglers who fished on the project, thank you for giving up your time to come
along on field trips. I hope that you learned something new and that you have gained a newfound
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respect for marine protected areas. Thank you to all the keen anglers who reported recaptured fish.
The information that you provided is indispensable in our understanding of fish ecology. Port Edward
Ski-boat Club are thanked for providing us with free access to the launch-site.

I thank my parents, Ronald and Giselle for supporting me through my life and providing me with
everything I have ever needed. To my father, I thank you for instilling in me, from a very young age, a
deep love of the ocean. You taught me to fish, spear-fish, crayfish and even how to look after marine
tanks. To my mother, I thank you for teaching me the discipline that I now treasure. And finally to my
wife, Adéle, thank you for your help with graphic editing but most importantly for encouraging me to
take up this career, when I thought it was impossible. I am indebted to you for everything.

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