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588
© Royal Swedish Academy of Sciences 2002 Ambio Vol. 31 No. 7-8, Dec. 2002
http://www.ambio.kva.se
INTRODUCTION
Seagrass ecosystems constitute an essential part of marine habi-
tats in continental shelf waters throughout the world. The dis-
tribution of seagrasses ranges from high intertidal to shallow
subtidal soft bottoms, i.e. sandy bays, mud flats, lagoons and es-
tuaries, where they often form extensive mono- and multispecific
meadows. In the tropics seagrass beds are commonly found ad-
jacent to coral reefs and mangroves. Seagrass beds are among
the most productive aquatic ecosystems in the biosphere (1) and
may increase biodiversity of associated organisms (e.g. 2–4).
They are important as nursery grounds, foraging areas and pre-
dation refuges for numerous fish and invertebrate populations
(5–7) and provide great benefits for commercial, subsistence and
recreational fisheries (8, 9). Due to the complex architecture of
the leaf canopy in combination with the dense network of roots
and rhizomes, seagrass beds stabilize bottom sediments (10) and
serve as effective hydrodynamic barriers reducing wave energy
and current velocity (11), thereby reducing turbidity (12) and
coastal erosion (13). Further, seagrass beds trap large amounts
of nutrients and organic matter in the bottom sediment (14, 15).
Through microbial decomposition, seagrass biomass may enter
the marine food web as detritus and thus support productivity
through recycling of nutrients and carbon (16, 17).
Seagrass ecosystems in the Western Indian Ocean (WIO) re-
gion have received limited scientific attention compared to man-
groves and coral reefs. The major part of seagrass research has
been conducted in Kenya, Tanzania, Mozambique, and eastern
South Africa, and deals mainly with seagrass diversity and ecol-
ogy (e.g. 18–22). Few reports deal with how seagrass beds are
used as natural resources (e.g. 23–26) or how they are affected
by human disturbance (e.g. 27, 28). Still they do play an impor-
tant role for the benefits of the local communities in the region,
especially in terms of fisheries (29).
This paper discusses and illustrates the ecological significance
of seagrass ecosystems in the WIO region, mainly from the per-
spective of fish and fisheries. Further, we present a case study
from Inhaca Island, Mozambique, that is one of the first quanti-
tative surveys of fish communities in seagrass beds in the WIO
region.
GEOGRAPHY
The WIO region, which has been characterized as a biogeo-
graphic subregion (30, 31), is a province of the Indian Ocean
encompassing the African east coast from Somalia to South Af-
rica (32) (Fig. 1). There are 10 states situated in the area of which
Somalia, Kenya, Tanzania, Mozambique, and South Africa be-
long to the mainland countries and the Seychelles, Comoros,
Reunion (belonging to France), Mauritius and Madagascar are
the Island States. The extension of the WIO coastline including
the Island States is about 12 000 km. A mosaic of different habi-
tats and substrates runs along the coastline, e.g. estuaries, coastal
lagoons, mangrove forests, coral reefs, seagrass beds, mud flats,
algal beds, barrier islands, and sandy and rocky beaches (33).
The average tidal range across the region varies from 2–4 m and
is semidiurnal (32, 34).
The climate and pattern of currents in the WIO are complex
and strongly influenced by the monsoonal circulation. Two dif-
ferent monsoon periods affect the region (34, 35). The South-
east monsoon (Apr–Oct) is distinguished by lower air tempera-
tures, strong winds and cool water with low productivity. The
Northeast monsoon (Nov–Mar) presents higher air temperatures
and weak winds (35).
SEAGRASS DISTRIBUTION AND ECOLOGY
IN THE WIO
Distribution
Extensive seagrass beds are found in all countries of the WIO
region. About 50 seagrass species have been described in the
world (36, 37), and the coastal zones of the WIO encompass 13
Seagrass Ecosystems in the Western Indian
Ocean
Martin Gullström, Maricela de la Torre Castro, Salomão O. Bandeira, Mats Björk,
Mattis Dahlberg, Nils Kautsky, Patrik Rönnbäck and Marcus C. Öhman
Seagrasses are marine angiosperms widely distributed in
both tropical and temperate coastal waters creating one
of the most productive aquatic ecosystems on earth. In the
Western Indian Ocean (WIO) region, with its 13 reported
seagrass species, these ecosystems cover wide areas of
near-shore soft bottoms through the 12 000 km coastline.
Seagrass beds are found intertidally as well as subtidally,
sometimes down to about 40 m, and do often occur in
close connection to coral reefs and mangroves. Due to the
high primary production and a complex habitat structure,
seagrass beds support a variety of benthic, demersal and
pelagic organisms. Many fish and shellfish species, includ-
ing those of commercial interest, are attracted to seagrass
habitats for foraging and shelter, especially during their
juvenile life stages. Examples of abundant and widespread
fish species associated to seagrass beds in the WIO
belong to the families Apogonidae, Blenniidae, Centris-
cidae, Gerreidae, Gobiidae, Labridae, Lethrinidae Lutja-
nidae, Monacanthidae, Scaridae, Scorpaenidae, Sigani-
dae, Syngnathidae and Teraponidae. Consequently, sea-
grass ecosystems in the WIO are valuable resources for
fisheries at both local and regional scales. Still, seagrass
research in the WIO is scarce compared to other regions
and it is mainly focusing on botanic diversity and ecology.
This article reviews the research status of seagrass beds
in the WIO with particular emphasis on fish and fisheries.
Most research on this topic has been conducted along the
East African coast, i.e. in Kenya, Tanzania, Mozambique
and eastern South Africa, while less research was carried
out in Somalia and the Island States of the WIO (Sey-
chelles, Comoros, Reunion (France), Mauritius and Mada-
gascar). Published papers on seagrass fish ecology in the
region are few and mainly descriptive. Hence, there is a
need of more scientific knowledge in the form of describing
patterns and processes through both field and experi-
mental work. Quantitative seagrass fish community studies
in the WIO such as the case study presented in this paper
are negligible, but necessitated for the perspective of
fisheries management. It is also highlighted that the pres-
sure on seagrass beds in the region is increasing due to
growing coastal populations and human disturbance from
e.g. pollution, eutrophication, sedimentation, fishing activi-
ties and collection of invertebrates, and its effect are little
understood. Thus, there is a demand for more research
that will generate information useful for sustainable
management of seagrass ecosystems in the WIO.
589Ambio Vol. 31 No. 7-8, Dec. 2002 © Royal Swedish Academy of Sciences 2002
http://www.ambio.kva.se
A seagrass
community
at Zanzibar,
Tanzania.
Photo:
K. Österlund Björk.
Inhaca
Island
Maputo
Maputo
Bay
01020
Km
SOMALIA
KENYA
TANZANIA
MOZAMBIQUE
SOUTH AFRICA
MADAGASCAR
Mozambique Channel
SEYCHELLES
INDIAN
OCEAN
MAURITIUS
REUNION
COMOROS
Maputo Bay
tats. Very common in the region are also Halophila ovalis (R.
Br.) Hook. f., Cymodocea rotundata Ehrenb. et Hempr. ex
Aschers., Cymodocea serrulata (R. Br.) Aschers. et Magnus,
Syringodium isoetifolium (Ascherson) Dandy and Halodule
uninervis (Forsk.) Aschers. in Bossier, whereas Halodule
wrightii Ascherson is mainly reported from Kenya and Tanza-
nia (39, Bandeira, Björk and S. Beer, unpubl. data). Occurrence
of Enhalus acoroides (L.f.) Royle, Halophila stipulacea (Forsk.)
Aschers. and Halophila minor (Zoll.) den Hartog is mainly re-
ported from northern Mozambique to Tanzania and in some lo-
cations in Kenya (40). Zostera capensis Setchell is only com-
mon in southern Mozambique and South Africa where large
monospecific stands may occur (38, 41), but the species has been
found also in Kenya (40). Ruppia maritima L. (which most au-
thors consider a seagrass) is found from eastern South Africa
northwards in the WIO region. In South Africa, R. maritima is
quite common in estuaries (42). In Mozambique this species oc-
curs mainly in brackish waters of the coastal lakes in the south-
ern part of the country and in Madagascar the species was de-
scribed as a member of the Madagascar floristic diversity by
Humbert and Jumelle (43).
Habitat
Many tropical seagrasses inhabit intertidal regions. As desicca-
tion resistance is limited in seagrass they must rely on ways of
avoiding desiccation rather than enduring it (37, 44, 45). The
depth limits of seagrasses are set by the light penetration.
Thalassodendron ciliatum has been reported to grow down to
40 m in clearer waters in the WIO (46). The seagrasses in the
WIO all need soft substrates like sand or mud except T. ciliatum
that has been reported to grow on bare rock in some exposed
localities in southern Mozambique (47). The seagrass habitats
in Kenya, Tanzania and northern Mozambique generally con-
sist of sediments from coral limestone, while the coastline in
southern Mozambique is principally made of sand (48, 49). The
organic loading of the sediment might be a critical factor for
seagrasses, because it affects the oxygen content. To battle an-
oxia, seagrasses have evolved ways of leading oxygen from the
shoot to the roots via the lacunae. This allows seagrasses to pro-
liferate in anoxic sediments but only up to a certain level. This
level has in Southeast Asian seagrass beds been given as 6% or-
ganic matter (DW) in the sediment (37).
Reproduction
Seagrasses in the WIO generally seem to have a vegetative
propagation since most species only rarely have been seen flow-
ering. Out of the 13 species occurring in the region, flowering
has been sporadically observed in Cymodocea serrulata, Enhalus
acoroides, Halodule uninervis, Halophila minor, and H.
stipulacea (41, 50). Frequent flowering occurs in a few species
such as Halophila ovalis, Syringodium isoetifolium, Thalassia
hemprichii and Thalassodendron ciliatum (Bandeira and Björk,
pers. comm.).
Structure and Function
Structural measurements on seagrasses of the mainland part of
the WIO region have mainly been performed in Thalassia
hemprichii, Thalassodendron ciliatum and Zostera capensis spe-
cies (e.g. 38, 51–54). These measurements included principally
Figure 1. Map showing the Western Indian Ocean region and the
location of Inhaca Island, Mozambique (the case study area).
known species (21) (Fig. 2). Mixed
seagrass beds with a high diversity
are common, up to 8 or 10 species
at the same locality have been re-
ported for Mozambique (38) and
Tanzania (Bandeira, Björk and S.
Beer, unpubl. data).
Two of the most common species
are Thalassia hemprichii (Ehren-
berg) Asherson and Thalassoden-
dron ciliatum (formerly Cymodocea
ciliata) (Forsk.) den Hartog, both
forming extensive beds in most
parts of the region. T. hemprichii
may usually be found in more pro-
tected habitats or on intertidal flats,
whereas T. ciliatum normally inhab-
its exposed or semi-exposed habi-
590
© Royal Swedish Academy of Sciences 2002 Ambio Vol. 31 No. 7-8, Dec. 2002
http://www.ambio.kva.se
biomass, leaf area, size measurements as well as C, N and P con-
tents. To date, the highest seagrass biomass in the WIO region
has been recorded for T. ciliatum at Inhaca Island with the total
biomass of 1070 g DW m
–2
(47). Functional aspects where meas-
ured in Kenya and Mozambique (e.g. 19, 47, 55) and included
mainly growth dynamics and nutrient resorption efficiency. T.
ciliatum leaf growth rate was estimated at 25 g DW m
–2
day
–1
and N and P resorption efficiency up to 32.4% and 34.3%, re-
spectively (38, 47). T. hemprichii resorption efficiency was up
to 3.0% for N and 0.3% for P (56). Ingram and Dawson (28),
species of crustaceans (harpacticoid copepods, amphipods, and
ostracods), bivalves, polychaetes, nematods, cumaceans, holo-
thuroids and phoronoids (62).
Seagrasses attract an assortment of organisms to proliferate
attached to the stem and leaf canopy. Tropical seagrass plants
are often inhabited by colonies of sessile fauna like bryozoans
and hydroids (60), in association with epiphytic algae and de-
tritus (63, 64). The fouling community also includes a like
number of motile meiofaunal organisms such as amphipods,
harpacticoid copepods, ostracods, nematodes, turbellarians,
Figure 2. Seagrass species
of the Western Indian
Ocean region. Illustrations
are modified from
Richmond (34).
one of the few works dealing
with aspects of structural eco-
logical measurements in the
Seychelles, studied leaf area
and shoot density in Cymo-
docea serrulata, Syringodium
isoetifolium and T. hemprichii.
ANIMAL COMMUNITIES
General Description
Seagrass beds in tropical re-
gions support a large variety
of associated faunal organisms
of different taxa with several
ecological characteristics (37).
Generally they contain greater
biodiversity and density of
animals than adjacent unvege-
tated habitats (e.g. 2). Sea-
grass habitats provide food,
shelter and nurseries for sev-
eral animals, including many
commercially important fish
and shellfish species (8), and
create remarkably high rates
of secondary productivity (e.g.
57–59). The 3-dimensional
structure of seagrass beds con-
tains a broad spectrum of
microhabitats and niches mak-
ing them convenient as per-
manent and transient resi-
dences for various benthic,
demersal and pelagic organ-
isms (60, 61). Animals living
within the bottom sediment
are dominated by invertebrate
Hydrocharytaceae Zosteraceae Cymodoceaceae Ruppiaceae
Cymodocea rotundata
Ruppia maritima
Enhalus acoroides
Halophila minor
Halophila ovalis
Halophila stipulacea
Thalassia hemprichii
Zostera capensis
Cymodocea serrulata
Halodule
sp
.
Syringodium isotifolium
Thalssodendron ciliatum
H. uninervis H. wrightii
591Ambio Vol. 31 No. 7-8, Dec. 2002 © Royal Swedish Academy of Sciences 2002
http://www.ambio.kva.se
polychaetes, foraminiferans, and gastropods (60, 63, 65). Occa-
sionally, substantial quantities of suspension feeding ascidians
are attached to seagrass leaves (66). The major taxa living on
the sediment surface in seagrass beds are echinoderms (starfish,
sea urchins, brittle stars and sea cucumbers), crustaceans (crabs)
and mollusks (bivalves and snails) (67, 68). The epibenthic fauna
also consist of mobile animals inhabiting the water over and un-
der the seagrass leaf canopy, and includes fish, decapod crusta-
ceans (prawns and shrimps) and cephalopods, as well as small
crustaceans like mysids, copepods (cyclopoids and calanoids),
amphipods and isopods (60, 69, 70). Many species spend their
postlarvae and juvenile stages in the seagrass beds before they
migrate into other habitats. The presence of juveniles of com-
mercially important penaeid prawns, with peak abundances dur-
ing relatively short periods of the year, have been reported in a
number of studies (e.g. 71–75).
The level of seagrass herbivory is thought to be very low ow-
ing to poor nutritional values, high C/N ratios and high cellu-
lose contents in the leaves of seagrasses (e.g. 76). Valentine and
Heck (77) suggested herbivory of seagrasses being underesti-
mated and reported that there is a need for more research in this
field. Cebrián and Duarte (78) showed that the herbivory pres-
sure could vary considerably among seagrass species. However,
a substantial fraction of tropical seagrass production may be di-
rectly consumed by herbivorous fish species and sea urchins (79,
80) as well as providing the main food of larger animals such
as dugongs and green turtles (81, 82).
Fish
Seagrass beds provide habitats for a variety of fish species (7,
69). It has been widely regarded that they support a higher di-
versity and abundance of associated fish than adjacent
unvegetated habitats (e.g. 83–86), although there are some con-
tradictions (e.g. 6, 87). Seagrass beds play an important role as
nursery areas for fish with a number of species that directly de-
pend on the seagrass habitat for their survival (e.g. 69; 88–90),
while other species have more general preferences (e.g. 91, 92).
According to Hemminga and Duarte (37), fish species living
within seagrass beds can be distinguished by their residence sta-
tus: i) permanent residents are species that spend their entire life
in seagrass beds; ii) temporary residents are species present sea-
sonally or during parts of their life in these habitats; iii) regular
visitors are species that frequently visit seagrass beds, e.g.
through diurnally migrations from an adjacent coral reef; iv) oc-
casional visitors are species that migrate to the beds sporadi-
cally.
In the WIO, few studies in fish ecology deal with fish bio-
diversity associated to seagrass beds. In reports from Kenya (23),
Tanzania (93), Mozambique (26, 94, this study) and Madagas-
car (95–97) typical seagrass associated fish communities have
been characterized. The most common species found belong to
the families Apogonidae, Blenniidae, Centriscidae, Gerreidae,
Gobiidae, Labridae, Lethrinidae Lutjanidae, Monacanthidae,
Scaridae, Scorpaenidae, Siganidae, Syngnathidae, and Terapo-
nidae. Some taxa were more restricted in their distribution, in-
cluding species belonging to Plotosidae in Kenya, Atherinidae
and Portunidae in Tanzania, and Pomacentridae and Tetra-
odontidae in Mozambique. Pollard (69) showed in a review on
the ecology of seagrass fish communities that the WIO region
was similar to other areas in terms of fish family composition.
In particular Blenniidae, Gerreidae, Gobiidae, Labridae, Mona-
canthidae, Sciaenidae, Scorpaenidae, Sparidae, Syngnathidae,
and Tetraodontidae were dominant throughout most seagrass
habitats and geographical areas.
A few studies in the WIO deal with feeding preferences and
trophic characters of fish in seagrass beds (e. g 25, 80, 98, 99).
Often the most commonly represented trophic category in
seagrass habitats is carnivorous fish (e.g. 98), even though vari-
ous important species prefer herbivorous diet (80, 99). The feed-
ing preferences may also differ between locations and seasons
(98).
FISHERIES ASSOCIATED WITH SEAGRASSES IN
THE WIO REGION
As a consequence of the high primary productivity and habitat
complexity, the secondary productivity in seagrass beds is sig-
nificant. Many of the species using seagrasses during their life
stages have a high commercial value (e.g. 100). The local popu-
lation of the coastal zone in the WIO region exploits seagrass
beds in two principal ways: by collection or fishing (e.g. 25, 29,
101–103).
Collectors that are active during low tides target invertebrates
such as cockles, cowries, octopus and other mollusks. Crabs and
lobsters are highly demanded as well as sea urchins and sea stars.
The most extensive commercial activity is the collection of sea
cucumbers. The fishery over seagrass beds in the WIO is per-
formed by artisanal fishermen with beach seine nets and trawl-
ing being the most common techniques. In addition, traps and
gillnets might be used.
Unfortunately, there is little documentation available that per-
mits an evaluation of the size and importance of those fisheries
in ecological, social and economic terms. Information on the
seagrass fisheries from the WIO is either scarce or difficult to
access as it may be in report form at local institutions or authori-
ties. However, Gell (29) and Gell and Whittington (26) have
documented the seagrass fishery and the diversity of fishes in
seagrass beds of Montepuez Bay in the north of Mozambique.
The results showed that the seagrass fishery was very important
at local levels. Seagrass fishery sustains over 400 fishermen in
the bay. The total fish catch from an area of 35 km
2
covered by
seagrass was estimated at about 500 t yr
–1
(or 14.3 t km
–2
yr
–1
),
with a market value of approximately USD 120 000. Part of the
catch went to direct consumption and part was traded. A posi-
tive correlation was found using catch per unit effort and total
seagrass cover as variables. According to the authors, this re-
sult indicates that seagrass coverage may influence fish biomass
and fishery productivity.
A number of authors suggest seagrass fisheries in the WIO
region to be substantial. McClanahan and Young (104), Ngoile
and Lindén (33) and Hinrichsen (105) have mentioned fishery
activities in the whole region, while other authors discuss the
importance of seagrass fisheries in specific countries, e.g. in
Kenya (106), Tanzania (102, 107) and Mozambique (27, 38).
Concrete examples of seagrass fisheries described in the litera-
ture are found in Chwaka Bay, Zanzibar (108); Kigomani, Zan-
zibar (109); Matemwe and Mkokotoni, Zanzibar (110); Inhaca
Bay (103); Mafia Island and Jibondo (102); the coasts of Tan-
zania, Zanzibar and Mafia Island (111). However, only few au-
thors, e.g. de Boer and Longamane (101), Gell (24) and de Boer
et al. (25), have made comprehensive studies on seagrass fish-
ery in the WIO. Numerous studies done in Australia, Europe,
and North America have shown the importance of seagrasses for
fisheries production (e.g. 75, 90, 112, 113).
ECONOMIC SIGNIFICANCE OF SEAGRASSES
Seagrasses are important economic assets in the WIO on both
regional and local scales. Some species of fish and shrimps are
export products that bring foreign income fundamental for the
economic development of the region. Seagrasses are valuable at
local levels since they contribute to the provision of protein and
cash income to the different human populations. Moreover,
seagrasses provide a range of goods and services apart from fish-
eries production. Some of the most important ecological serv-
ices identified for seagrass habitats are primary and secondary
592
© Royal Swedish Academy of Sciences 2002 Ambio Vol. 31 No. 7-8, Dec. 2002
http://www.ambio.kva.se
production, enhancement of biodiversity and erosion control (e.g.
37, 114, 115). Despite these facts, few efforts on economic valu-
ation of seagrasses have been done not only in the WIO, but also
in general.
Costanza et al. (116) reviewed the global economical value
of 17 ecosystems services for 16 biomes and calculated that
seagrass/algal beds are estimated to generate gross financial ben-
efits amounting 19 000 USD ha
–1
yr
–1
. This is the third highest
total value of the biomes involved (close to the values
of estuaries and floodplains) and about 10 times the estimated
value of tropical rain forests. Watson et al. (117) estimated the
nursery function of the seagrasses for prawn fisheries in Cairns
Harbor, Australia. The area studied was dominated by a mix of
the seagrass species Zostera capricorni and Halodule pinifolia.
The approximate area was 876 ha and the value calculated was
between 365 and 1324 USD ha
–1
yr
–1
.
Once seagrasses have been damaged, restoration costs can be
very high (118). Restoration of seagrasses has to be planned in
appropriate places and a large set of different conditions has to
be fulfilled to achieve success (e.g. 119, 120). Further, the hy-
drodynamics of particular areas are significant as to seagrass loss
and recovery (e.g. 121). There is little information about the suc-
cess of restoration in terms of recovering the whole complexity
of the original system (115).
The economic importance of seagrasses is obvious because
they are essential ecosystems for fisheries production. Fish prod-
ucts are important economic assets not only in local but also in
international markets. Since the fisheries fraction of the total
value of seagrass beds is high, the benefit of beds including all
ecological functions can be substantial.
THREATS
During the last decades seagrass degradation have received in-
creased attention worldwide (122). Widespread losses of seagrass
habitats are reported from many coastal areas including North
America (123), Australia (124), Europe (125, 126) and Africa
(Gullström, unpubl. data). Seagrass demise might be induced by
natural events such as storms (127) or diseases (128). Seagrass
loss, however, mainly occurs due to human impacts and the most
general explanation for reduction of seagrass is excessive nutri-
ent enrichment, i.e. eutrophication, of coastal waters (e.g. 129–
131). Effluent disposal (132) and changes in land-use patterns
(133) are other important anthropogenic disturbances that
threaten seagrass populations. As mentioned, human pressure is
important and one of the driving forces shaping the coast of WIO
is the rapid demographic growth. High nativity rates and migra-
tion from inlands to the coastal zone have contributed to an in-
creased coastal population which are now supporting about 35
million people or about one third of the total population of the
East African region (134).
Environmental impact studies of the human activities on
seagrasses are scarce in the WIO. Factors like deforestation, col-
lection of invertebrates, destructive fishing practices, sediment
alteration, waste disposal (domestic and industrial), construction
work activities, changing water regimes through damming or
deviation of rivers and estuaries, unsuitable farming methods and
wastes from oil tankers have, however, been mentioned as ac-
tivities that threaten seagrasses (27, 135).
Municipal waste problems may vary between countries in the
WIO. One important issue is the low capacity and outdated tech-
nology of most sewage systems in the region. The sewage sys-
tem of Dar es Salaam is planned to be replaced and modernized
during the coming 8 years. The systems in Mozambique are very
deficient in both rural and urban areas, while Somalia and Mada-
gascar have no systems at all (105). In the Seychelles, Ingram
and Dawson (28) investigated the effect of untreated river ef-
fluents. Their results indicated that sedimentation, salinity and
water quality deriving from discharges were the most important
factors affecting seagrass growth.
The industrialization of the WIO region is still low, but grow-
ing. Agricultural activities, sugar mills and factories producing
a variety of products such as textiles, soaps and plastics have
been reported as sources of pollutants into coastal waters (104,
105, 136). The effects of industrial wastes on seagrass beds have
been little explored. However, studies have demonstrated the
ability of seagrasses to bioaccumulate heavy metals (122). The
effects of organic loads from fish farms on the seagrass
Posidonia oceanica have been investigated (137, 138). A reduc-
tion in water transparency and an increase in dissolved nutrients
and organic content in sediments reduced the shoot size, leaf
growth rates and leaves per shoot of seagrasses. Mechanical
damage through clearing of seagrasses to make open space for
tourism and aquaculture as well as coastal development in the
form of housing and harbor structures might also be a threat.
Certain species are vulnerable to physical damage and have prob-
lems in recovering over a reasonable time span. However, it is
unclear to what extent the collection of invertebrates by locals
may damage seagrasses. Boese (139) investigated the effects of
recreational clam harvesting on Zostera marina in Yaquina Bay,
Newport, USA. The study showed that benthic infaunal com-
munities were not affected while seagrass biomass was reduced.
The author suggested that the results should be taken with cau-
tion since no long-term effects were considered.
One of the most negative impacts on seagrasses is the
destabilization of sediments due to the impossibility for the ma-
jority of seagrasses to root in high dynamic and mobile sediment
environments (e.g. 37), so if adjacent ecosystems such as man-
groves and coral reefs are disturbed the sedimentation and en-
ergy patterns might change and seagrasses will be affected (e.g.
100). Seagrass loss is generally not a gradual slow rate process;
rather it seems to be a rapid self-accelerating chain effect proc-
ess (140). Losses of mangroves and coral reef areas could also
have a negative impact on adjacent seagrass beds (141, 142).
Other causes of water clarity reduction are sediment loading in
the coasts through land-use changes, mangrove cutting and
dredging activities causing higher sediment transport. Some con-
struction-related activities like tourism, housing, commerce and
mining might contribute to sediment loading as well.
MANAGEMENT ISSUES
In the WIO region seagrass beds have been little considered in
management plans. Indirectly, they have been taken into account
when protected areas or conservation projects are implemented,
but no direct attention has been given to seagrass ecosystems.
The efforts to adopt Integrated Coastal Zone Management
(ICZM) in the WIO started in the 1980s and in 1993 the Arusha
Resolution on Integrated Coastal Zone Management was signed
in response to the UN Rio Conference in 1992 (143). Regional
nongovernmental organizations have taken initiatives to promote
ICZM and the Western Indian Ocean Marine Scientist Associa-
tion (WIOMSA) is an example of an organization, where scien-
tists participate with research for development and management.
Programs based on community development and participation
had been the most successful activities in the region (144). With
this background, the future efforts trying to manage and protect
the extensive seagrass beds in the WIO have to be designed.
Seagrasses play an important role in the livelihoods of coastal
communities, even though the relationship between seagrasses
and welfare might not be directly apparent to managers and de-
cision makers. Fishermen take large catches from seagrass beds,
collectors of invertebrates depend on the seagrass habitat to find
their products, and in time of crisis probably the local knowl-
edge of eating the seeds of seagrasses is still present. To high-
light these links to the local population is an important action
593Ambio Vol. 31 No. 7-8, Dec. 2002 © Royal Swedish Academy of Sciences 2002
http://www.ambio.kva.se
to manage seagrass beds. A combined strategy of local partici-
pation and education, while speeding up the acquisition of
knowledge and baseline data of seagrasses in the region, seems
to be appropriated at present. The socioeconomic importance and
the design of proper institutions (formal and informal) for ef-
fective management of seagrasses also need to be highlighted.
Finally, seagrasses must be seen as part of the seascape con-
tinuum, where a number of ecosystems interact with each other
and respond to human activities in the coastal zone.
A CASE STUDY AT INHACA ISLAND, MOZAMBIQUE
The dynamics of fish communities in seagrass beds have been
studied in many tropical coastal waters (e.g. 69, 145–147). In
the Western Indian Ocean (WIO) region, however, studies of
seagrass fish communities are few and deal mainly with species
composition and relative abundance (e.g. 23, 26, 93–97). The
study presented here examines density, biomass and spatial dis-
tribution of fish assemblages in different seagrass habitats and
is one of the first investigations that reveal quantitative fish data
from seagrass beds in the WIO. A more detailed description on
species level will be given by Gullström et al. (unpubl.).
The study was carried out at Inhaca Island situated about 35
km eastward of Maputo, southern Mozambique (Lat. 25°58'–
26°05'S; Long. 32°55'–33°00'E) (Fig. 1). Fish were sampled dur-
ing 4 consecutive spring tide periods in October and November
1999 at 4 sites in 2 seagrass communities, Thalassodendron
ciliatum / Cymodocea serrulata (TC) and Thalassia hemprichii
/ Halodule wrightii (TH) (mapped and identified by Bandeira,
2000). The sampling was conducted in daylight, 0–3 hrs before
high tide and at depths of 1.4–2.9 m, using a beam trawl with
an opening of 1.44 x 0.43 m. The net had an unstretched mesh
dimension of 6 mm and a cod-end of 3 mm mesh size. In the
laboratory, all fishes were identified to the lowest taxonomic
level possible and counted. The individuals were measured for
standard length (SL) to the nearest mm and wet weight to the
nearest 0.01 g.
A total of 2102 fish individuals belonging to 56 different taxa
from 27 families were recorded during the study at Inhaca. The
family Siganidae (represented by only one species, i.e. Siganus
sutor) dominated the catch and was ranked first by overall abun-
dance (23.2%) and biomass (30.7%). Labridae (21.2%),
Monacanthidae (15.7%) and Teraponidae (7.9%) were also abun-
dant, while high biomass was found of Teraponidae (10.3%),
Labridae (9.7%), Lethrinidae (7.5%), Platycephalidae (7.0%) and
Scaridae (6.7%). The results showed a total fish density of 0.11
± 0.02 ind. m
–2
in TC and 0.02 ± 0.004 ind. m
–2
in TH, and a
total fish biomass of 0.99 ± 0.21 g m
–2
for TC and 0.18 ± 0.08 g
m
–2
for TH (Fig. 3). The differences between the two seagrass
communities can be explained by various biotic and abiotic
mechanisms. As suggested in the literature (e.g. 91, 148, 149),
the main reasons for spatial heterogeneity of fish in seagrass beds
may be due to differences in plant morphology and structural
complexity, significant factors for the efficiency of shelter
against predation and foraging success. Epiphytic algae on the
stems and leaves of seagrasses might also be important for the
distribution of fish as they provide food for many marine organ-
isms (150). Further, the composition of seagrass species in the
two types of seagrass communities (38) as well as the zonation
of seagrasses due to the tidal gradient around Inhaca Island may
also influence the distribution of fish. TC occurs within or in
close connection to subtidal areas, whereas TH has its main ex-
tension in the intertidal zone and, thus, longer air exposure dur-
ing low tide. In addition, existing hydrodynamic conditions can
also be relevant for the fish-habitat interactions in seagrass beds.
In Table 1, fish standing stock data from this study have been
compared to other studies with quantitative data in different
seagrass habitats. Both fish density and biomass seem to be quite
low, but are still within the similar range as the comparative stud-
ies, where the density ranged from 0.02 to 6.08 ind. m
–2
and the
Figure 3. Mean density (a) and biomass (b) ± SE of total fish catch from
4 sites in 2 different seagrass community types around Inhaca Island,
Mozambique. TCB =
Thalassodendron ciliatum
/
Cymodocea serrulata
at the Biological station area (n = 10); TCP =
Thalassodendron ciliatum
/
Cymodocea serrulata
at the Porthino area (n = 3); THP =
Thalassia
hemprichii
/
Halodule wrightii
at the Porthino area (n = 3); THS =
Thalassia hemprichii
/
Halodule wrightii
at the Saco da Inhaca area (n =
3).
Table 1. Fish standing stock in seagrass beds.
Location Community Density Biomass Source
(ind. m
–2
) (g m
–2
)
Puerto Rico
Thalassia testudinum
and 0.65–3.15 Martin and Cooper (152)
Syringodium filiforme
Northeast Australia Seagrass areas 0.5–1.8 Blaber et al. (145)
(mainly
Enhalus acoroides
)
Groote Eylandt, Short seagrass sites 0.57–2.21 Blaber et al. (91)
northern Australia
Groote Eylandt, Tall seagrass sites 0.16–3.84 Blaber et al. (91)
northern Australia
Cairns, Australia 8 seagrass species 0.88 Coles et al. (75)
(mainly
Zostera capricorni
)
Southern Australia Different seagrasses 3.03–6.08 1.67–2.58 Edgar et al. (112)
Maine, USA
Zostera marina
1.12 Mattila et al. (86)
Inhaca Island,
Thalassodendron ciliatum
and 0.11 ± 0.02 0.99 ± 0.21 This study
Mozambique
Cymodocea serrulata
Inhaca Island,
Thalassia hemprichii
and 0.02 ± 0.004 0.18 ± 0.08 This study
Mozambique
Halodule wrightii
BIOMASS (b)
DENSITY (a)
Sampling site
Sampling site
Ind. m
–2
g m
–2
0.15
0.10
0.05
0.00
1.5
1.0
0.5
0.0
TCB TCP THP THS
TCB TCP THP THS
594
© Royal Swedish Academy of Sciences 2002 Ambio Vol. 31 No. 7-8, Dec. 2002
http://www.ambio.kva.se
References and Notes
1. Duarte, C.M. and Chiscano, C.L. 1999. Seagrass biomass and production: A reassess-
ment. Aquat. Bot. 65, 159–174.
2. Edgar, G.J., Shaw, C., Watson, G.F. and Hammond, L.S. 1994. Comparisons of spe-
cies richness, size-structure and production of benthos in vegetated and unvegetated
habitats in Western Port, Victoria. J. Exp. Mar. Biol. Ecol. 176, 201–226.
3. Oshima, Y., Kishi, M.J. and Sugimoto, T. 1999. Evaluation of the nutrient budget in
a seagrass bed. Ecol. Model., 115, 19–33.
4. Boström, C. and Bonsdorff, E. 2000. Zoobenthic community establishment and habi-
tat complexity—the importance of seagrass shoot-density, morphology and physical
disturbance for faunal recruitment. Mar. Ecol. Prog. Ser. 205, 123–138.
5. Adams, S.M. 1976. The ecology of eelgrass, Zostera marina (L.), fish communities.
I. Structural analysis. J. Exp. Mar. Biol. Ecol. 22, 269–291.
6. Heck, K.L., Jr. and Thoman, T.A. 1984. The nursery role of seagrass meadows in the
upper and lower reaches of the Chesapeake Bay. Estuaries 7, 70–92.
7. Orth, R.J., Heck, K.L., Jr. and van Montfrans, J. 1984. Faunal communities in seagrass
beds: A review of the influence of plant structure and prey characteristics on preda-
tor-prey relationships. Estuaries 7, 339–350.
8. Bell, J.D. and Pollard, D.A. 1989. Ecology of fish assemblages and fisheries associ-
ated with seagrasses. In: Biology of Seagrasses—A Treatise on the Biology of
Seagrasses with Special Reference to the Australian Region. Larkum, A.W.D.,
McComb, A.J. and Sheperd S.A. (eds). Elsevier, Amsterdam, pp. 565–609.
9. Rooker, J.R., Holt, S.A., Soto, M.A. and Holt, G.J. 1998. Postsettlement patterns of
habitat use by sciaenid fishes in subtropical seagrass meadows. Estuaries 21, 318–
327.
10. Fonseca, M.S. 1989. Sediment stabilization by Halophila decipiens in comparison to
other seagrasses. Estuar. Coast. Shelf Sci. 29, 501–507.
11. Koch, E.W. 1996. Hydrodynamics of a shallow Thalassia testudinum bed in Florida,
USA. In: Seagrass Biology: Proc. International Workshop, Rottnest Island, Western
Australia, 25–29 January 1996. Kuo, J., Phillips, R.C., Walker, D.I. and Kirkman, H.
(eds). Faculty of sciences, The University of Western Australia, pp. 105–110.
12. Bulthuis, D.A., Brand, G.W. and Mobley, M.C. 1984. Suspended sediments and nu-
trients in water ebbing from seagrass-covered and denuded tidal mudflats in a south-
ern Australian embayment. Aquat. Bot. 20, 257–266.
13. Almasi, M.N., Hoskin, C.M., Reed, J.K. and Milo, J. 1987. Effects of natural and ar-
tificial Thalassia on rates of sedimentation. J. Sediment. Petrol. 57, 901–906.
14. Smith, S.V. 1981. Marine macrophytes as a global carbon sink. Science 211, 838–
840.
15. Gacia, E., Granata, T.C. and Duarte, C.M. 1999. An approach to measurement of par-
ticle flux and sediment retention within seagrass (Posidonia oceanica) meadows. Aquat.
Bot. 65, 255–268.
16. Livingston, R.J. 1984. The relationship of physical factors and biological response in
coastal seagrass meadows. Estuaries 7, 377–390.
Figure 4. Multidimensional
scaling (MDS) plots, based
on Bray-Curtis similarity
matrix on double square
root transformed data, of
fish density (a) and
biomass (b).
■ =
Thalassodendron
ciliatum
/
Cymodocea
serrulata
at the Biological
station area;
● =
Thalassodendron
ciliatum
/
Cymodocea
serrulata
at the Porthino
area;
● =
Thalassia hemprichii
/
Halodule wrightii
at the
Porthino area;
▲ =
Thalassia hemprichii
/
Halodule wrightii
at the
Saco da Inhaca area.
biomass from 0.16 to 3.84 g m
–2
. Fish represented in this study
were mainly of juvenile life-stages, possibly a result of the sam-
pling technique used (148), and in turn this could underestimate
the amount of fish. However, this study shows that the spatial
distribution of fish in seagrass beds is highly variable, but indi-
cates an interaction between fish assemblage structure and
seagrass community composition (Fig. 4).
CONCLUDING REMARKS
Seagrass beds represent an important component of the tropical
coastal zone and show similar magnitudes of productivity and
fish biomass as coral reefs and mangroves. Still they have re-
ceived much less attention than the other systems in terms of
research and management. In the WIO region the pressure on
the seagrass ecosystems is increasing due to a growing coastal
population and overexploitation of resources. Artisanal and
small-scale fisheries as well as the collection of invertebrates at
low tides are activities that may affect the biological food web
17. Hemminga, M.A., Harrison, P.G. and Lent, F. 1991. The balance of nutrient losses
and gains in seagrass meadows. Mar. Ecol. Prog. Ser. 71, 85–96.
18. Adams, J.B. and Talbot, M.M.B. 1992. The influence of river impoundment on the
estuarine seagrass Zostera capensis Setchell. Bot. Mar. 35, 69–75.
19. Duarte, C.M., Hemminga, M.A. and Marbà, N. 1996. Growth and population dynam-
ics of Thalassodendron ciliatum in a Kenyan back-reef lagoon. Aquat. Bot. 55, 1–11.
20. Bandeira, S.O. 1997. Dynamics, biomass and total rhizome length of the seagrass
Thalassodendron ciliatum at Inhaca Island, Mozambique. Plant Ecol. 130, 133–141.
21. Bandeira, S.O. and Björk, M. 2001. Seagrass research in the Eastern Africa region:
Emphasis on diversity ecology and ecophysiology. S. Afr. J. Bot. 67, 420–425.
22. Leilaert, F., Vanreusel, W., De Clerk, O. and Coppejans, E. 2001. Epiphytes on the
seagrasses of Zanzibar Island (Tanzania), floristic and ecological aspects. Belg. J. Bot.
134, 3–20.
23. van der Velde, G., Dehairs, F., Marguillier, S., Mwatha, G.K., Op ´t Veld, R.L.J.M.,
Rajagopal, S. and Van Avesaath, P.H. 1995. Structural and stable isotope differences
in the fish communities of mangrove creeks, seagrass meadows and sand flats in Gazi
Bay (Kenya). In: Interlinkages between Eastern-African coastal ecosystems. Nether-
lands Institute of Ecology, Centre for Estuarine and Coastal Ecology, Yerseke, The
Netherlands, pp. 132–157.
24. Gell, F.R. 1999. Fish and Fisheries in the Seagrass Beds of the Quirimba Archipelago,
Northern Mozambique. PhD Thesis, University of York, United Kingdom.
25. de Boer, W.F., Van Schie, A.M.P., Jocene, D.F., Mabote, A.B.P. and Guissamulo, A.
2001. The impact of artisanal fishery on a tropical intertidal benthic fish community.
Environ. Biol. Fishes 61, 213–229.
26. Gell, F.R. and Whittington, M.W. 2002. Diversity of fishes in seagrass beds in the
Quirimba Archipelago, northern Mozambique. Mar. Freshwater Res. 53, 115–121.
27. Bandeira, S.O. 1995. Marine botanical communities in southern Mozambique: Sea
grass and seaweed diversity and conservation. Ambio 24, 506–509.
28. Ingram, J.C. and Dawson, T.P. 2001. The impacts of a river effluent on the coastal
seagrass habitats of Mahé, Seychelles. S. Afr. J. Bot. 67, 483–487.
29. Gell, F.R. 2000. The seagrass fishery of Montepuez Bay, Northern Mozambique. In:
Seas at the Millennium: An Environmental Evaluation, Vol III. Sheppard, C.R.C. (ed.).
Elsevier, Amsterdam, pp. 106.
30. Sheppard, C.R.C. 1997. Coral reefs of the Indian Ocean: Regional overview. In: Proc.
Natl. Conf. Coral Reefs, Zanzibar, Tanzania. Johnstone, R.W., Francis, J. and
Muhando, C.A. (eds). SIDA/UDSM/UNEP, pp. 12–15
31. Sheppard, C.R.C., Price, A. and Roberts, C.M. (eds) 1992. Marine Ecology of the Ara-
bian Region. Academic Press, London, 359 pp.
32. Longhurst, A. (ed.) 1998. Ecological Geography of the Sea. Academic Press, Lon-
don, 398 pp.
33. Ngoile, M. and Lindén, O. 1997. Lessons learned from Eastern Africa: The develop-
ment of policy on ICZM. Ocean Coastal Mgmt 37, 295–318.
within a seagrass bed. As the case study suggests, there is an
interaction between fish distribution and seagrass communities,
likewise it might be a similar kind of interaction between
seagrasses and other marine organisms. Eutrophication, sediment
loading, mechanical damage and effluent disposal are examples
of other human-induced threats that may have negative impacts
on seagrass habitats. Direct protection of seagrass ecosystems
has not been considered in the WIO, but sometimes conserva-
tion occurs within systems where seagrasses are interlinked with
adjacent habitats such as coral reefs and mangroves.
Besides basic research studies there is a need for studies ad-
dressing ecological valuation, impact assessment, pollution in-
fluences and linkages to other habitats. It is important to accel-
erate the acquisition of knowledge and to try working in inter-
disciplinary groups running parallel projects considering ecologi-
cal and economic aspects. Thus, for a future efficient and sus-
tainable coastal zone planning and management of the seagrass
habitats in the WIO, monitoring and evaluation of the ecologi-
cal conditions as well as research are indispensable.
DENSITY
(a)
BIOMASS
(b)
595Ambio Vol. 31 No. 7-8, Dec. 2002 © Royal Swedish Academy of Sciences 2002
http://www.ambio.kva.se
Estuar. Coast. Shelf Sci. 23, 901–908.
73. Robertson, A.I. and Duke, N.C. 1987. Mangroves as nursery sites: Comparisons of
the abundance and species composition of fish and crustaceans in mangroves and other
nearshore habitats in tropical Australia. Mar. Biol. 96, 193–205.
74. Sheridan, P.F. 1992. Comparative habitat utilization by estuarine macrofauna within
the mangrove ecosystem of Rookery Bay, Florida. Bull. Mar. Sci. 50, 21–39.
75. Coles, R.G., Lee Long, W.J., Watson, R.A. and Derbyshire, K.J. 1993. Distribution
of seagrasses, and their fish and penaeid prawn communities, in Cairns harbour, a tropi-
cal estuary, Northern Queensland, Australia. Aust. J. Mar. Freshwater Res. 44, 193–
210.
76. Thayer, G.W., Bjorndal, K.A., Ogden, J.C., Williams, S.L. and Zieman, J.C. 1984.
Role of larger herbivores in seagrass communities. Estuaries 7, 351–376.
77. Valentine, J.F. and Heck, K.L., Jr. 1999. Seagrass herbivory: Evidence for the contin-
ued grazing of marine grasses. Mar. Ecol. Prog. Ser. 176, 291–302.
78. Cebrian, J. and Duarte, C.M. 1998. Patterns in leaf herbivory on seagrasses. Aquat.
Bot. 60, 67–82.
79. McClanahan, T.R., Nugues, M. and Mwachireya, S. 1994. Fish and sea urchin
herbivory and competition in Kenyan coral reef lagoons: The role of reef manage-
ment. J. Exp. Mar. Biol. Ecol. 184, 237–254.
80. Mariani, S. and Alcoverro, T. 1999. A multiple-choice feeding-preference experiment
utilising seagrasses with a natural population of herbivorous fishes. Mar. Ecol. Prog.
Ser. 189, 295–299.
81. Zieman, J.C., Iverson, R.L. and Ogden, J.C. 1984. Herbivory effects on Thalassia
testudinum leaf growth and nitrogen content. Mar. Ecol. Prog. Ser. 15, 151–158.
82. Preen, A. 1995. Impacts of dugong foraging on seagrass habitats: Observational and
experimental evidence for cultivation grazing. Mar. Ecol. Prog. Ser. 124, 201–213.
83. Sogard, S.M. and Able, K.W. 1991. A comparison of eelgrass, sea lettuce macroalgae,
and marsh creeks as habitats for epibenthic fishes and decapods. Estuar. Coast. Shelf
Sci. 33, 501–519.
84. Connolly, R.M. 1994. Removal of seagrass canopy: Effects on small fish and their
prey. J. Exp. Mar. Biol. Ecol. 184, 99–110.
85. Jenkins, G.P., May, H.M.A., Wheatley, M.J. and Holloway, M.G. 1997. Comparison
of fish assemblages associated with seagrass and adjacent unvegetated habitats of Port
Phillip Bay and Corner Inlet, Victoria, Australia, with emphasis on commercial spe-
cies. Estuar. Coast. Shelf Sci. 44, 569–588.
86. Mattila, J., Chaplin, G., Eilers, M.R., Heck, K.L., Jr., O’Neal, J.P. and Valentine, J.F.
1999. Spatial and diurnal distribution of invertebrate and fish fauna of a Zostera ma-
rina bed and nearby unvegetated sediments in Damariscotta River, Maine (USA). J.
Sea Res. 41, 321–332.
87. Hanekom, N. and Baird, D. 1984. Fish community structures in Zostera and non-
Zostera regions of the Kromme Estuary, St. Francis Bay. S. Afr. J. Zool./S.-Afr. Tydskr.
Dierkd. 19, 295–301.
88. Parrish, J.D. 1989. Fish communities of interacting shallow-water habitats in tropical
oceanic regions. Mar. Ecol. Prog. Ser. 58, 143–160.
89. Tolan, J.M., Holt, S.A. and Onuf, C.P. 1997. Distribution and community structure of
ichthyoplankton in Laguna Madre seagrass meadows: Potential impact of seagrass spe-
cies change. Estuaries 20, 450–464.
90. Guidetti, P. and Bussotti, S. 2000. Fish fauna of a mixed meadow composed by the
seagrasses Cymodocea nodosa and Zostera noltii in the Western Mediterranean.
Oceanol. Acta 23, 759–770.
91. Blaber, S.J.M., Brewer, D.T., Salini, J.P., Kerr, J.D. and Conacher, C. 1992. Species
composition and biomasses of fishes in tropical seagrasses at Groote Eylandt, north-
ern Australia. Estuar. Coast. Shelf Sci. 35, 605–620.
92. Jenkins, G.P. and Wheatley, M.J., 1998. The influence of habitat structure on nearshore
fish assemblages in a southern Australian embayment: Comparison of shallow seagrass,
reef-algal and unvegetated sand habitats, with emphasis on their importance to recruit-
ment. J. Exp. Mar. Biol. Ecol. 221, 147–172.
93. Muhando, C.A. 1995. Species composition and relative abundance of fish and macro-
custacea in seagrass beds, mangroves and coral reefs (Zanzibar, Tanzania). In:
Interlinkages Between Eastern-African Coastal Ecosystems. Netherlands Institute of
Ecology, Centre for Estuarine and Coastal Ecology, Yerseke, The Netherlands, pp.
158–165.
94. Almeida, A.J., Saldanha, L. and André, E. 1995. Fishes in the seagrass beds of the
Inhaca Island (Mozambique)—community structure and dynamic. In: Interlinkages
Between Eastern-African Coastal Ecosystems. Netherlands Institute of Ecology, Cen-
tre for Estuarine and Coastal Ecology, Yerseke, The Netherlands, pp. 284–297.
95. Mauge, L.A. 1967. Contribution preliminaire a l´inventaire ichthyologique de la région
de Tulear. Rec. Trav. Sta. Mar. Endoume, Suppl. 7, 101–132.
96. Vivien, M.L. 1974. Ichtyofaune des herbiers de phanérogames marines du Grand Recif
de Tulear (Madagascar). 1. Les Peuplements et leur distribution ecologique. Tèthys 5,
425–436.
97. Harmelin-Vivien, M.L. 1983. Etude comparative de l´ichtyofaune des herbiers de
phanerogames marines en milieux tropical et tempéré. Rev. Ecol. Terre Vie 38, 179–
210.
98. Almeida, A.J., Amoedo, L. and Saldanha, L. 1995. Fishes in the seagrass beds of the
Inhaca Island (Mozambique)—cold season. In: Interlinkages Between Eastern-Afri-
can Coastal Ecosystems. Netherlands Institute of Ecology, Centre for Estuarine and
Coastal Ecology, Yerseke, The Netherlands, pp. 298–306.
99. Almeida, A.J., Marques, A. and Saldanha, L. 1995. Fishes in the seagrass beds of the
Inhaca Island (Mozambique)—dynamic, feeding habits and sexual development of
three species. In: Interlinkages Between Eastern-African Coastal Ecosystems. Neth-
erlands Institute of Ecology, Centre for Estuarine and Coastal Ecology, Yerseke, The
Netherlands, pp. 307–314.
100. Ogden, J.C. 1988. The influence of adjacent systems on the structure and function of
coral reefs. In: Proc. 6th International Coral Reef Symposium. Choat, J.H., Barnes,
D., Borowitzka, M.A., Coll, J.C., Davies, P.J., Flood, P., Hatcher, B.G., Hopley, D.,
et al. (eds). Australia, pp. 123–129.
101. de Boer, W.F. and Longamane, F.A. 1996. The exploitation of intertidal food resources
in Inhaca Bay, Mozambique, by shorebirds and humans. Biol. Conserv. 78, 295–303.
102. Lindén, O. and Lundin, C.G. 1996. Integrated Coastal Zone Management in Tanza-
nia. Report published by Sida (Stockholm) in cooperation with the World Bank and
the Government of Tanzania, 166 pp.
103. Lindén, O. and Lundin, C.G. 1997. Integrated Coastal Zone Management in Mozam-
bique. Report published by Sida (Stockholm) in cooperation with the World Bank and
the Government of Mozambique, 148 pp.
104. McClanahan, T.R. and Young, T.P. (eds) 1996. East African Ecosystems and Their
Conservation. Oxford University Press, Oxford, 452 pp.
105. Hinrichsen, D. 1998. Coastal Waters of the World: Trends, Threats and Strategies.
Island Press, Washington, 275 pp.
106. Emerton, L., and Tessema, Y. 2000. Economic Constraints to the Management of Ma-
rine Protected Areas: The Case of Kisite Marine National Park and Mpungiti Marine
National Reserve, Kenya. IUCN, Nairobi, Kenya, 30 pp.
107. Masalu, D.C.P. 2000. Coastal and Marine resource use conflicts and sustainable de-
velopment in Tanzania. Ocean Coastal Mgmt 43, 475–494.
108. Mohammed, S.M. (ed.) 1999. The Ecology and Socioeconomy of Chwaka Bay, Zan-
zibar. Report Prepared for Jozani—Chwaka Bay Conservation Project, CARE, Tan-
zania, 48 pp.
34. Richmond, M.D. (ed.) 1997. A Guide to the Seashores of Eastern Africa and the West-
ern Indian Ocean Islands. Sida-SAREC, Stockholm, 448 pp.
35. McClanahan, T.R. 1996. Oceanic ecosystems and pelagic fisheries. In: East African
Ecosystems and Their Conservation. McClanahan, T.R. and Young, T.P. (eds). Ox-
ford University Press, Oxford, pp. 39–65.
36. den Hartog, C. 1970. The Seagrasses of the World. Amsterdam: North Holland Publi-
cation Co, 275 pp.
37. Hemminga, M.A. and Duarte, C.M. (eds) 2000. Seagrass Ecology. Cambridge Uni-
versity Press, Cambridge, 298 pp.
38. Bandeira, S.O. 2000. Diversity and Ecology of Seagrasses in Mozambique: Emphasis
on Thalassodendron ciliatum Structure, Dynamics, Nutrients and Genetic Variability.
PhD Thesis, Göteborg University, Sweden.
39. Short, F.T. and Coles, R. (eds) 2001. Seagrass Research Methods. Elsevier Publish-
ing, The Netherlands, 210 pp.
40. UNEP. 1998. Eastern Africa Atlas of Coastal Resources: Kenya, 119 pp.
41. Isaac, F.M. 1968. Marine botany of the Kenya coast. 4. Angiosperms. J. E. Afr. Nat.
Hist. Soc. 27, 29–47.
42. Colloty, B.M. 2000. Botanical Importance of Estuaries of the Former Ciskei/Transkei
Region. PhD Thesis, Department of Botany, University of Port Elizabeth.
43. Humbert, H. and Jumelle, H. 1950. Flore de Madagascar et des Comores. Potamo-
gétonaces et Naiadacées. Muséum National d’Histoire Natuirelle (Phanérogamie),
Paris.
44. Powell, G.V.N. and Schaffner, F.C. 1991. Water trapping by seagrasses occupying
bank habitats in Florida Bay. Estuar. Coast. Shelf Sci. 32, 43–60.
45. Björk, M., Uku, J., Weil, A. and Beer S. 1999. Photosynthetic tolerances to desicca-
tion of tropical intertidal seagrasses. Mar. Ecol. Prog. Ser. 191, 121–126.
46. Aleem, A.A. 1984. Distribution and ecology of seagrass communities in the western
Indian Ocean. Deep-Sea Res. 31, 919–933.
47. Bandeira, S.O. 2002. Leaf production rates Thalassodendron ciliatum from rocky and
sandy habitats. Aquat. Bot. 72, 13–24.
48. Hartnoll, R.G. 1976. The ecology of some rocky shores in tropical East Africa. Estuar.
Coast. Mar. Sci. 4, 1–21.
49. Gove, D.Z. 1995. The coastal zone of Mozambique. In: Proc. Workshop and Policy
Conference on Integrated Coastal Zone Management in Eastern Africa Including the
Island States. Lindén, O. (ed.). Coastal Management Center (CMC), Manila, Philip-
pines, pp. 251–275.
50. McMillan, C. 1980. Flowering under controlled conditions by Cymodocea serrulata,
Halophila stipulacea, Syringodium isoetifolium, Zostera capensis and Thalassia
hemprichii from Kenya. Aquat. Bot. 8, 323–336.
51. Uku, J.N., Martens, E.E. and Mavuti, K.M. 1996. An ecological assessment of littoral
seagrass communities in Diani and Galu coastal beaches, Kenya. In: Current Trends
in Marine Botanical Research in the East African Region. Björk, M., Semesi, A.K.,
Pedersén, M. and Bergman, B. (eds). SIDA, pp. 280–302.
52. Ochieng, C.A. and Erftemeijer, P.L.A. 1999. Accumulation of seagrass beach cast along
the Kenyan coast: a quantitative assessment. Aquat. Bot. 65, 221–238.
53. de Boer, W.F. 2000. Biomass dynamics of seagrasses and the role of mangroves and
seagrass vegetation as different nutrient sources for an intertidal ecosystem. Aquat.
Bot. 66, 225–239.
54. Kamermans, P., Hemminga, M.A., Marbà, N., Mateo, M.A., Mtolera, M. and Stapel,
J. 2001. Leaf production, shoot demography, and flowering of Thalassodendron
ciliatum along East African coast. Aquat. Bot. 70, 243–258.
55. Hemminga, M.A., Gwada, P., Slim, F.J., de Koeyer, P. and Kazungu, J. 1995. Man-
grove outwelling and the functioning of adjacent seagrass meadows (Gazi Bay, Kenya).
In: Interlinkages Between Eastern-African Coastal Ecosystems. Netherlands Institute
of Ecology, Centre for Estuarine and Coastal Ecology, Yerseke, The Netherlands, pp.
74–81.
56. Martin, A.R.O. and Bandeira, S.O. 2001. Biomass and Leaf Nutrients of Thalassia
hemprichii at Inhaca Island, Mozambique. S. Afr. J. Bot. 67, 439–442.
57. Edgar, G.J. 1990. The influence of plant structure on the species richness, biomass
and secondary production of macrofaunal assemblages associated with Western Aus-
tralian seagrass beds. J. Exp. Mar. Biol. Ecol. 137, 215–240.
58. Fredette, T.J., Diaz, R.J., Monterans, J. and Orth, R.J. 1990. Secondary production
within a seagrass bed (Zostera marina and Ruppia maritima ) in lower Chesapeake
Bay. Estuaries 13, 431–440.
59. Valentine, J.F. and Heck, K.L., Jr. 1993. Mussels in seagrass meadows: Their influ-
ence on macroinvertebrate abundance and secondary production in the northern Gulf
of Mexico. Mar. Ecol. Prog. Ser. 96, 63–74.
60. Kikuchi, T. and Pérès, J.M. 1977. Consumer ecology of seagrass beds. In: Seagrass
Ecosystems—A Scientific Perspective. McRoy, C.P. and Helfferich, C. (eds). Marcel
Dekker, Inc., New York, pp. 147–193.
61. Robbins, B.D. and Bell, S.S. 1994. Seagrass landscapes: A terrestrial approach to the
marine subtidal environment. Trends Ecol. Evol. 9, 301–304.
62. Howard, R.K., Edgar, G.J. and Hutchings, P.A. 1989. Faunal assemblages of seagrass
beds. In: Biology of Seagrasses—A Treatise on the Biology of Seagrasses with Spe-
cial Reference to the Australian Region. Larkum, A.W.D., McComb, A.J. and Sheperd
S.A. (eds). Elsevier, Amsterdam, pp. 536–564.
63. Kitting, C.L. 1984. Selectivity by dense populations of small invertebrates foraging
among seagrass blade surfaces. Estuaries 7, 276–288.
64. van Montfrans, J., Wetzel, R.L. and Orth, R.J. 1984. Epiphyte-grazer relationships in
seagrass meadows: Consequences for seagrass growth and production. Estuaries 7,
289–309.
65. Bell, S.S., Walters, K. and Kern, J.C. 1984. Meiofauna from seagrass habitats: A re-
view and prospectus for future research. Estuaries 7, 331–338.
66. Lemmens, S.J., Kirkpatrick, D. and Thompson, P. 1996. The clearance rate of four
ascidians from Marmion Lagoon, Western Australia. In: Seagrass Biology: Proc. In-
ternational Workshop, Rottnest Island, Western Australia, 25–29 January 1996. Kuo,
J., Phillips, R.C., Walker, D.I. and Kirkman, H. (eds). Faculty of sciences, The Uni-
versity of Western Australia, pp. 277–282.
67. Kirkman, H., Humphries, P. and Manning, R. 1991. The epibenthic fauna of seagrass
beds and bare sand in Princess Royal Harbour and King George Sound, Albany, south-
western Australia. In: The Marine Flora and Fauna of Albany, Western Australia.
Wells, F.E., Walker, D.I., Kirkman, H. and Lethbridge, R. (eds). Proc. 3rd Interna-
tional Marine Biological Workshop, Western Australian Museum, pp. 553–563.
68. Kalk, M. 1995. A Natural History of Inhaca Island, Mozambique. Witwatersrand Uni-
versity Press, South Africa, 395 pp.
69. Pollard, D.A. 1984. A review of ecological studies on seagrass-fish communities, with
particular reference to recent studies in Australia. Aquat. Bot. 18, 3–42.
70. Sanchez, A.J., Raz-Guzman, A. and Barba, E. 1996. Habitat value of seagrasses for
decapods in tropical coastal lagoons of the southwestern Gulf of Mexico: An over-
view. In: Seagrass Biology: Proc. International Workshop, Rottnest Island, Western
Australia, 25–29 January 1996. Kuo, J., Phillips, R.C., Walker, D.I. and Kirkman, H.
(eds). Faculty of sciences, The University of Western Australia, pp. 233–240.
71. Staples, D.J., Vance, D.J. and Heales, D.S. 1985. Habitat requirements of juvenile
penaeid prawns and their relationship to offshore fisheries. In: Second Australian Na-
tional Prawn Seminar. Rothlisberg, P.C., Hill, B.J. and Staples, D.J. (eds). CSIRO,
Cleveland, pp. 47–54.
72. de Freitas, A.J. 1986. Selection of nursery areas by six Southeast African Penaeidae.
596
© Royal Swedish Academy of Sciences 2002 Ambio Vol. 31 No. 7-8, Dec. 2002
http://www.ambio.kva.se
109. Wieggel, W., 1995. Intertidal Collection of Shellfish and Other Marine Products by
the Community of Kigomani, Zanzibar. Draft. Institute of Marine Sciences, Zanzibar,
Tanzania.
110. Jiddawi, N.S. and Stanley, R.D. 1999. A study of the artisanal fishery landings in the
villages of Matemwe and Mkokotoni, Zanzibar, Tanzania. In: Fisheries Stock Assess-
ment in the Traditional Fishery Sector: The Information Needs. Jiddawi, N.S. and
Stanley, R.D. (eds). Proc. National Workshop on the Artisanal Fisheries Sector, Zan-
zibar, September 22–24, 1997. Institute of Marine Sciences, University of Dar es Sa-
laam, Zanzibar, Tanzania, pp. 48–73.
111. Newton, L.C., Parkes, E.V.H. and Thompson, R.C. 1993. The effects of shell collect-
ing on the abundance of gastropods on Tanzanian shores. Biol. Conserv. 63, 241–245.
112. Edgar, G.J. and Shaw, C. 1995. The production and trophic ecology of shallow-water
fish assemblages in southern Australia 1. Species richness, size-structure and produc-
tion of fishes in Western Port, Victoria. J. Exp. Mar. Biol. Ecol. 194, 53–81.
113. Rozas, L.P. and Minello, T.J. 1998. Nekton use of salt marsh, seagrass, and non veg-
etated habitats in a South Texas estuary. Bull. of Mar. Sci. 63, 481–501.
114. Duarte, C.M. 2000. Marine biodiversity and ecosystem services: An elusive link. J.
Exp. Mar. Biol. Ecol. 250, 117–131.
115. Moberg, F. and Rönnbäck, P. 2001. Ecosystem services of the tropical seascape: In-
teractions, substitutions and restoration. In: Human Use and Abuse of Coral Reefs Man-
aging for Ecosystem Services and Resilience. Moberg, F. PhD Thesis, Stockholm Uni-
versity, Stockholm, Sweden.
116. Costanza, R., d’Arge, R., de Groot, R., Farber, S., Grasso, M., Hannon, B., Limburg,
K., Naeem, S., ONeill, R.V., Paruelo, J., Raskin, R.G, Sutton, P. and van den Belt,
M. 1997. The value of the world’s ecosystem services and natural capital. Nature 387,
253–260.
117. Watson, R.A., Coles, R.G. and Lee Long, W.J. 1993. Simulation estimates of annual
yield and landed value for commercial penaeid prawns from a tropical seagrass habi-
tat. Aust. J. Mar. Freshwater Res. 44, 211–219.
118. NOAA, 1997. Primary Restoration. Silver Springs, MD: National Oceanic and At-
mospheric Administration, Damage Assessment and Restoration Program, USA.
119. Sheridan, P., McMahan G., Hammerstrom K. and Pulich, W., Jr. 1998. Factors Af-
fecting Restoration of Halodule wrightii to Galveston Bay, Texas. Restor. Ecol. 6, 144–
158.
120. van Katwijk, M.M., Hermus, D.C.R., de Jong, D.J., Asmus, R.M. and de Jonge, V.N.
2000. Habitat suitability of the Wadden Sea for restoration of Zostera marina beds.
Helg. Mar. Res. 54, 117–128.
121. Fonseca, M.S. and Bell, S.S. 1998. Influence of physical setting on seagrass landscapes
near Beaufort, North Carolina, USA. Mar. Ecol. Prog. Ser. 171, 109–121.
122. Short, F.T. and Wyllie-Echeverria, S. 1996. Natural and human-induced disturbance
of seagrasses. Environ. Conserv. 23, 17–27.
123. Orth, R.J. and Moore, K.A. 1983. Chesapeake Bay: An unprecedented decline in sub-
merged aquatic vegetation. Science 222, 51–53.
124. Walker, D.I. and McComb, A.J. 1992. Seagrass degradation in Australian coastal wa-
ters. Mar. Pollut. Bull. 25, 191–195.
125. Pasqualini, V., Pergent-Martini, C. and Pergent, G. 1999. Environmental impact iden-
tification along the Corsican coast (Mediterranean sea) using image processing. Aquat.
Bot. 65, 311–320.
126. Baden, S.P., Gullström, M., Lundén, B., Pihl, L. and Rosenberg, R. Vanishing seagrass
(Zostera marina, L.) in Swedish coastal waters. Ambio. (In print).
127. Gallegos, M.E., Merino, M., Marba, N. and Duarte, C.M. 1992. Flowering of Thalassia
testudinum Banks ex Koenig in the Mexican Caribbean: Age-dependence and
interannual variability. Aquat. Bot. 43, 249–255.
128. den Hartog, C., 1987. “Wasting disease” and other dynamic phenomena in Zostera
beds. Aquat. Bot. 27, 3–14.
129. Kemp, W.M., Twilley, R.R., Stevenson, J.C., Boynton, W.R. and Means, J.C. 1983.
The decline of submerged vascular plants in upper Chesapeake Bay: Summary of re-
sults concerning possible causes. Mar. Technol. Soc. J. 17, 78–89.
130. Tomasko, D.A., Dawes, C.J. and Hall, M.O. 1996. The effects of anthropogenic nu-
trient enrichment on turtle grass (Thalassia testudinum) in Sarasota Bay, Florida. Es-
tuaries 19, 448–456.
131. McGlathery, K.J. 2001. Macroalgal blooms contribute to the decline of seagrass in
nutrient-enriched coastal waters. J. Phycol. 37, 453–456.
132. Larkum, A.W.D. and West, R.J. 1990. Long-term changes of seagrass meadows in
Botany Bay, Australia. Aquat. Bot. 37, 55–70.
133. Shepherd, S.A., McComb, A.J., Bulthuis, D.A., Neverauskas, V.P., Steffensen, D.A.
and West, R.J. 1989. Decline of seagrasses. In: Biology of Seagrasses—A Treatise on
the Biology of Seagrasses with Special Reference to the Australian Region. Larkum,
A.W.D., McComb, A.J. and Sheperd S.A. (eds). Elsevier, Amsterdam, pp. 346–387.
134. UNEP 1997. Report prepared for the global programme of action for the protection
of the marine environment from land-based activities in the Eastern African region
and the protection and management of the marine and coastal areas in the Eastern Af-
rican region (EAF/5), 49 pp.
135. Ruwa, R.K. 1996. Intertidal wetlands. In: East African Ecosystems and Their Con-
servation. McClanahan, T.R. and Young, T.P. (eds). Oxford University Press, Oxford,
pp. 101–127.
136. Coughanowr, C.A., Ngoile, M. and Lindén, O. 1995. Coastal zone management in
Eastern Africa including the island states: A review of issues and initiatives. Ambio
24, 448–457.
137. Delgado, O., Ruiz, J., Pérez, M., Romero, J. and Ballesteros, E. 1999. Effects of fish
farming on seagrass (Posidonia oceanica) in a Mediterranean Bay: Seagrass decline
after organic loading cessation. Oceanol. Acta 22, 109–117.
138. Ruiz, J.M., Pérez, M. and Romero, J. 2001. Effects of fish farm loadings on seagrass
(Posidonia oceanica) distribution, growth and photosynthesis. Mar. Pollut. Bull. 42,
749–760.
139. Boese, B.L. 2002. Effects of recreational clam harvesting on eelgrass (Zostera ma-
rina) and associated infaunal invertebrates: in situ manipulative experiments. Aquat.
Bot. 73, 63–74.
140. Duarte, C.M. 1995. Submerged aquatic vegetation in relation to different nutrient re-
gimes. Ophelia 41, 87–112.
141. Semesi, A.K. 1998. Mangrove management and utilization in Eastern Africa. Ambio
27, 620–626.
142. Valiela, I. and Cole, M.L. 2002. Comparative evidence that salt marshes and man-
groves may protect seagrass meadows from land-derived nitrogen loads. Ecosystems
5, 92–102.
143. Lindén, O. and Lundin, C.G. 1997. The Journey from Arusha to Seychelles: Successes
and Failures in Integrated Coastal Zone Management in Eastern Africa and Island
States. Proc. Second Policy Conference on Integrated Coastal Zone Management in
Eastern Africa and Island States, Seychelles, 23–25 October, 1996. Report published
by Sida (Stockholm) in cooperation with the World Bank and the Government of Sey-
chelles, 298 pp.
144. Moffat, D., Ngoile, M., Lindén, O. and Francis, J. 1998. The reality of the stomach:
Coastal management at the local level in Eastern Africa. Ambio 27, 590–598.
145. Blaber, S.J.M., Brewer, D.T. and Salini, J.P. 1989. Species composition and biomasses
of fishes in different habitats of a tropical northern Australian estuary: Their occur-
rence in the adjoining sea and estuarine dependence. Estuar. Coast. Shelf Sci. 29, 509–
531.
146. Sedberry, G.R. and Carter, J. 1993. The fish community of a shallow tropical lagoon
in Belize, Central America. Estuaries 16, 198–215.
147. Nagelkerken, I., Kleijnen, S., Klop, T., van den Brand, R., de la Moriniere, E.C. and
van der Velde, G. 2001. Dependence of Caribbean reef fishes on mangroves and
seagrass beds as nursery habitats: A comparison of fish faunas between bays with and
without mangroves/seagrass beds. Mar. Ecol. Prog. Ser. 214, 225–235.
148. Heck, K.L., Jr. and Orth, R.J. 1980. Seagrass habitats: The roles of habitat complex-
ity, competition and predation in structuring associated fish and motile macro-
invertebrate assemblages. In: Estuarine Perspectives. Kennedy, V.S. (ed.). Academic
Press, New York, pp. 449–464.
149. Heck, K.L., Jr and Thoman, T.A. 1981. Experiments on predator-prey interactions in
vegetated aquatic habitats. J. Exp. Mar. Biol. Ecol. 53, 125–134.
150. Borowitzka, M.A. and Lethbridge, R.C. 1989. Seagrass epiphytes. In: Biology of
Seagrasses—A Treatise on the Biology of Seagrasses with Special Reference to the
Australian Region. Larkum, A.W.D., McComb, A.J. and Sheperd S.A. (eds). Elsevier,
Amsterdam, pp. 458–499.
151. Petrik, R. and Levin, P.S. 2000. Estimating relative abundance of seagrass fishes: A
quantitative comparison of three methods. Environ. Biol. Fishes 58, 461–466.
152. Martin, F.D. and Cooper, M. 1981. A comparison of fish faunas found in pure stands
of two tropical Atlantic seagrasses, Thalassia testudinum and Syringodium filiforme.
Northeast Gulf Sci. 5, 31–37.
153. Acknowledgements. This study was supported by the Sida/SAREC Bilateral Marine
Science Programme between Sweden and Tanzania (Sida = Swedish International De-
velopment and Cooperation Agency).
Martin Gullström is a PhD student at the Department of Marine
Ecology, Göteborg University, Sweden. His research interests
relate to ecology and human disturbance of seagrass ecosystems
in tropical and temperate coastal zones. His address: Kristineberg
Marine Research Station, SE-450 34 Fiskebäckskil, Sweden.
E-mail: martin.gullstrom@kmf.gu.se
Maricela de la Torre Castro is a PhD student at the Department of
Systems Ecology, Stockholm University, Sweden. Her present
research focuses on seagrasses as natural resources and how the
presence of seagrasses contributes to human welfare. Her
address: Department of Systems Ecology, Stockholm University,
SE-106 91, Sweden.
E-mail: maricela@ecology.su.se
Salomão Bandeira is a lecturer in botany at the Department of
Biological Sciences, Universidade Eduardo Mondlane,
Mozambique. He obtained his PhD at the University of Göteborg,
Sweden, and his main research interests cover seagrass and
seaweed diversity and ecology. Salomão Bandeira is currently the
Head of the Department of Biological Sciences, Universidade
Eduardo Mondlane. His address: Department of Biological
Sciences, Universidade Eduardo Mondlane, P.O. Box 257, Maputo,
Mozambique.
E-mail: sband@zebra.uem.mz
Mats Björk, PhD, is associate professor in plant physiology at the
Botany Department of Stockholm University. He has specialized in
seaweed and seagrass physiology on relation to pollution, and is
also one of the coordinators of the bilateral Sida/SAREC Marine
program between Sweden and Tanzania. His address: Botany
Department, Stockholm University, SE-106 91 Stockholm, Sweden.
E-mail: mats.bjork@botan.su.se
Mattis Dahlberg, MSc in Marine biology, Göteborg University,
Sweden, has been involved in seagrass research activities at
Inhaca Island, Mozambique. His address: Department of Marine
Ecology, Göteborg University, Kristineberg Marine Research
Station, SE-450 34 Fiskebäckskil, Sweden.
E-mail: mattis.dahlberg@hotmail.com
Nils Kautsky is professor of marine ecotoxicology at Department
of Systems Ecology, Stockholm University and Deputy Director of
The Beijer International Institute for Ecological Economics at the
Swedish Royal Academy of Sciences. He has more than 20 years
of experience of coordinating projects on marine ecology,
aquaculture and coastal area management in Africa, Asia and
Latin America. His address: Department of Systems Ecology,
Stockholm University, SE-106 91 Stockholm, Sweden.
E-mail: nils@system.ecology.su.se
Patrik Rönnbäck has a PhD in systems ecology from the
Department of Systems Ecology, Stockholm University, Sweden.
His research interests relate to Ecological Economics analysis of
fisheries, aquaculture and mangrove ecosystem. His address:
Department of Systems Ecology, Stockholm University, SE-106 91
Stockholm, Sweden.
E-mail: pat@system.ecology.su.se
Marcus Öhman, PhD, is a research scientist and senior lecturer at
the Department of Zoology, Stockholm University, Sweden. His
research interests are in marine ecology, fisheries, disturbance
effects on the marine biota, environmental economics and coastal
zone management. He is also a coordinator and research advisor
for various Sida supported marine science projects in East Africa,
South Asia and in the Caribbean. His address: Department of
Zoology, Stockholm University, SE-106 91 Stockholm, Sweden.
E-mail: marcus.ohman@zoologi.su.se
