Seaweed farming and artisanal fisheries in an Indonesian seagrass bed

133 Pages·2008·4.78 MB·English

by  Sven Uli Blankenhorn

Seaweed farming and artisanal fisheries
in an Indonesian seagrass bed
–
Complementary or competitive usages?

Sven Uli Blankenhorn

Vorgelegt im Fachbereich 2 (Biologie/Chemie) der Universität Bremen
als Dissertation zur Erlangung des akademischen Grades eines
Doktors der Naturwissenschaften (Dr. rer. nat.)
Alfred Wegener Institute for Polar- and Marine Research
Wadden Sea Station Sylt

Seaweed farming and artisanal fisheries in an Indonesian seagrass bed
–
Complementary or competitive usages?

submitted by
Sven Uli Blankenhorn
in partial fulfilment of the requirements for the degree of
Doctor of Natural Sciences (Dr. rer. nat.)

Faculty 2 Biology / Chemistry
University Bremen
June 2007

Gutachter der Dissertation: Prof. Dr. W. Arntz, AWI Bremerhaven / Universität Bremen
Dr. H. Asmus, AWI Wattenmeerstation Sylt

Tag des öffentlichen Kolloquiums: 13.07.2007

SPICE – Science for the Protection of Indonesian Coastal Ecosystems
This thesis is part of the SPICE (Science for the Protection of Indonesian Coastal Ecosys-
tems) program, Cluster 1: Coral Reef Based Ecosystems, founded by the BmB+F (German
federal ministry for education and research). Additional funding was provided by the DAAD
(German Academic Exchange Service).
„Kalau tidak ada rumput laut Puntondo mati.”
“Without seaweed Puntondo would be dead.”
Daeng Laga, village chief of Puntondo
previous page: Satellite image of the western part of Laikang Bay, South Sulawesi, Indonesia. Puntondo on
the small peninsula extending into the bay. Source: GoogleEarth

Disclaimer
Herewith I assure that I wrote this thesis independently and that I did not use any additional
help except to the extend and the manner stated. References are cited in compliance with
guidelines on safeguarding good scientific practice.
Bremen, June 4th 2007

Sven Blankenhorn
CONTENTS
Contents
ACKNOWLEDGEMENTS............................................................................................................................................viii
SUMMARY..................................................................................................................................................................ix
ZUSAMMENFASSUNG.................................................................................................................................................xi
RINGKASAN...............................................................................................................................................................xiii
GENERAL INTRODUCTION...........................................................................................................................................1
The seagrass environment 1
Mediation of oceanographic parameters 2
Enrichment of coastal biodiversity 3
Human influences 4
Seaweed farming 5
Culture of carrageenophytes in South-East Asia 5
Farming methods 6
Effects on the environment 10
Artisanal fisheries 10
Fisheries management 11
Marine protected areas and alternative livelihoods 11
Traditional knowledge 12
Aims of the thesis 12
Socio-economic aspects of seaweed farming 12
Long-term effects of seaweed farming on seagrass beds 13
Economically important fish species, methods and fishing habitats 13
Fish stocks and gill net fishery in seagrass beds 13
Seagrass beds as a common resource for seaweed farming and fisheries 14
RESULTS OF THE THESIS.............................................................................................................................................15
Socio-economic aspects of seaweed farming 15
Long-term effects of seaweed farming on seagrass beds 15
Economically important fish species, methods and fishing habitats 16
Fish stocks and gill net fishery in seagrass beds 17
GENERAL DISCUSSION..............................................................................................................................................19
Sustainability of seaweed farming 19
Sustainability of artisanal fisheries 20
Seagrass beds as a common resource for seaweed farming and fisheries 20
Seaweed farming as an alternative livelihood 21
References 22

v
CONTENTS
CHAPTER 1 SEAWEED FARMING IN TRADITIONAL FISHING VILLAGES:
AN EXAMPLE FROM SOUTH SULAWESI, INDONESIA.........................................................................34
Abstract 34
Keywords 34
Introduction 34
Methods 35
Results 36
Economic activities and effort 37
Seaweed culture and fishing problems 39
Market problems and income 39
Satisfaction with seaweed farming and fisheries, hopes for the future 40
Discussion 41
Economic activities and effort 41
Seaweed culture and fishing problems 43
Market problems and income 44
Satisfaction with seaweed farming and fisheries, hopes for the future 45
Conclusion 45
Acknowledgements 46
References 46
CHAPTER 2 LONG-TERM EFFECTS OF FLOATING LONG-LINE SEAWEED FARMING
ON SEAGRASS SHOOT DENSITY AND BIOMASS.................................................................................50
Abstract 50
Keywords 50
Introduction 51
Methods 52
Study area 52
Experimental design 53
Field sampling and laboratory analysis 54
Statistical analysis 54
Results 55
Shoot density 55
Biomass 57
Discussion 59
Shoot density 59
Biomass 60
Conclusion and recommendation 62
Acknowledgements 63
References 63
Appendix 66
CHAPTER 3 FISHERMEN’S PERCEPTION OF ARTISANAL FISHERIES AND
IMPLICATIONS FOR MANAGEMENT IN A BAY IN SOUTH SULAWESI, INDONESIA.............................73
Abstract 73
Keywords 73
Introduction 73
vi
CONTENTS
Methods 75
Study area 75
Community surveys 76
Literature data 76
Statistical analysis 76
Results 77
Fished species and local names 77
Used gear, catch habitat and abundance 77
Fish sizes 83
Average and maximum length at site compared to literature data 83
Market prices and economical value 84
Assessment of food items, trophic levels, and habitats 86
Discussion 88
Fished species and local names 88
Used gear, catch habitat and abundance 88
Fish sizes 90
Average and maximum length at site compared to literature data 90
Assessment of food items, trophic levels, and habitats 90
Market prices and economical value 91
Conclusion and recommendation 92
Acknowledgements 93
References 93
CHAPTER 4 VARIATIONS IN FISH STOCKS AND ARTISANAL GILL NET FISHERY
IN AN INDONESIAN SEAGRASS BED..................................................................................................98
Abstract 98
Keywords 98
Introduction 98
Methods 100
Study site 100
Sampling strategy and measured parameters 101
Statistical analysis 102
Results 103
General catch characteristics 103
Diurnal fluctuations 106
Lunar fluctuations 106
Seasonal fluctuations 107
Discussion 110
General catch characteristics 111
Diurnal fluctuations 112
Lunar fluctuations 113
Seasonal fluctuations 113
Conclusion 114
Acknowledgements 114
References 115
vii
CONTENTS
Acknowledgements
I would like to thank my first supervisor Prof. Dr. Wolf Arntz for his willingness to supervise
this thesis despite of his more than busy schedule. My second supervisor Dr. Harald Asmus
is thanked for supporting my research ideas. He gave me great freedom in every way to plan
and conduct my field research, which was highly appreciated.
The warm welcome at the AWI Wadden Sea Station by Dr. Ragnhild Asmus, Dr. Patrick
Polte, and Dr. Anja Schanz was very pleasurable. Birgit Hussel is thanked for help in the
laboratory and organizing shippment of scientific equipment. During her stay in Indonesia
Andrea Bäurle made the days in the lab much more fun. Dominik Kneer, Hung Liu, and Pe-
ter Schauerte were great friends during their time in Indonesia.
At UNHAS in Makassar Prof. Dr. Ambo Tuwo at the Faculty of Oceanography and Fisher-
ies and Dr. Jamaluddin Jompa at the CCRR provided valuable help in organizing the stay at
their institution. Especially Dr. Magdalena Litaay is thanked for dealing with day-to-day
problems and making many, many calls to keep things running. Dodi Priosambodo’s help in
correcting my Indonesian writing not only in this thesis was highly appreciated. Mastar, Pak
Ridwan, Ulla, and many others helped in many ways to organize the research.
At the ZMT in Bremen Dr. Eberhard Krain has to be thanked for his invaluable efforts
dealing with visa and customs officials. Prof. Dr. Venugopalan Ittekkot and Dr. Claudio Rich-
ter were irreplaceable in planning and running the SPICE program and cluster 1, respec-
tively. The discussions with Esther Borell and Leyla Knittweis were very fruitful and will not
be forgotten.
In Puntondo, without the support by PPLH-Puntondo, especially Daeng Laga, Beatrix,
Wajib, Yuli, and Yeny my research would not have been possible. LIPI in Jakarta, and espe-
cially Pak Ruben, is thanked for issuing a research permit. The DAAD scholarship for the
first 18 months of my stay in Indonesia was of great help.
My friends in Germany, especially Florian, Matthias and his wife Martina, Roland and his
wife Mamisolo, and Steffen always welcomed me very warmly during my few stays, it felt as
if I never had been away. In Makassar, Adi, Edi, Ningsih, and Ema were great fun.
Without the support of my parents during long years in school, university and Indonesia I
would not have succeeded. They gave me the independence I needed do to my thesis under
conditions which were challenging. My brother Kai and his girlfriend Eri often enough were
very competent and ready to help with computer problems.
Without my girlfriend Titi it would have suffered from serious depressions and with her
childish (in the best possible meaning) ways she understood to cheer me up and to forget
about the daily chaos.
viii
SUMMARY
Summary
In Indonesia, coastal villages traditionally strongly depend on artisanal fisheries. With
increasing population density (and hence fishing pressure), alternative sources of income be-
come more important. One possible economic activity is seaweed farming, which has been
introduced in many communities since the 1980’s. There, algae farming is restricted to shal-
low coastal waters and their natural ecosystems, e. g. seagrass beds. Seagrass beds themselves
are important habitats for many species of fish, shrimp and crab which are the basis for
traditional fisheries. Therefore, if seaweed farming causes the seagrass ecosystem to change,
its economical benefits might be outbalanced by losses in the fisheries sector. The field re-
search for this thesis included investigations of seaweed farming and its economic impor-
tance, its influence seagrass flora, the economic importance of artisanal fishery’s practices
and implications for management, and the variation of fish stock and gill net fishery in the
seagrass bed off Puntondo, a small village in district Takalar, South Sulawesi, Indonesia.
In chapter 1, a study of economical activities and the effort allocated to each of them in
Puntondo is presented. Problems as well in seaweed culture and marketing as well as in fish-
eries as perceived by the villagers were evaluated. Seaweed farming was practiced by nearly
all villagers and contributed a very high percentage to average household income. Both sea-
weed farming and fisheries were believed to have high future prospects and wanted to be de-
veloped by the villagers. The results are discussed in detail in chapter 1 and it is concluded,
that, based on economical considerations, efforts to increase production in the area should
mainly focus on increasing productivity by improving post-harvest processing. Further de-
velopment of seaweed farming in other areas should not only take environmental suitability
of proposed sites into account, but also consider market access as a viable factor for con-
tinuous and predictable income. In community development plans, other sources of alterna-
tive income should be included, as seaweed prices can oscillate significantly.
Chapter 2 deals with the effects of shading, trampling, a combination of both factors, and
actual seaweed farming in different intensities on seagrass. High shading intensities reduced
the performance of small seagrass species, whereas trampling was only effective in combina-
tion with shading. Compared to small seagrasses, the big species Enhalus acoroides was
much less influenced by any treatment. Farming itself however had less influence than could
be expected from shading / trampling manipulations. The results are discussed in detail in
chapter 2 and a seedling density of approximately 185.000 seedlings ha–1 is estimated to be
environmentally sustainable. Current farming densities were below this threshold level but
still, based on ecological considerations, production should be increased by establishing
farms in deeper waters, away from fragile benthic communities like seagrasses and corals. In
ix