Vol.2, No.11, 1274-1286 (2010) Natural Science
Copyright © 2010 SciRes. OPEN ACCESS
Diet of fish populations in posidonia oceanica meadows
off the Island of Ischia (Gulf of Naples, Italy):
assessment of spatial and seasonal variability
Valerio Zupo1*, Dorothea Stübing2
1Functional and Evolutionary Ecology Lab. Stazione Zoologica Anton Dohrn. Punta San Pietro, Ischia. Italy; *Corresponding author:
2Marine Zoology, University of Bremen, Bremen, Germany
Received 25 June 2010; revised 28 July 2010; accepted 5 August 2010.
The gut contents of fish in three Posidonia oce-
anica meadows off the island of Ischia (Bay of
Naples, Italy) were investigated. A total of 926
individual fish belonging to 28 species was
sampled by bottom trawl in the leaf canopy.
Labridae, Pomacentridae, Scorpaenidae, and
Serranidae were the best represented families
(41%, 38%, 8% and 6% of the total number of
individuals, respectively). Of the 94 taxa de-
tected in the gut contents, 42 were identified to
the species level. The most common food items
were decapod crustaceans (15% of the gut
contents, on average), copepods (13%), am-
phipods (14%), brown fragments of P. oceanica
(6%), and ostracods (6%). The most abundant
species of labridae, Symphodus ocellatus and S.
rostratus, showed a broad spectrum of prey.
This generalist feeding may positively influence
their numerical abundance. Seasonal variations
in the diets of fish, also at prey-species level,
were demonstrated. The fish taxon plays essen-
tially a macro-carnivore trophic role. In the in-
vestigated seagrass meadows the main trophic
fluxes start from plant detritus, macrophyta, and
microphyta (as primary producers) towards
crustacean decapods, copepods, ostracods,
and gammarid amphipods (as secondary pro-
ducers) to fish. A low recycling rate (4%) within
the fish community was observed. Larger fish
predators (e.g., Sparidae), swimming over the
leaf canopy, are the main exporters to adjacent
coastal systems.
Keywords: Fish; Food Webs; Spatial Variability;
Posidonia Oceanica; Seagrass; Seasonality
The presence of seagrasses provides effective pro-
tection against predation [1-3]; therefore it is accom-
panied by a great abundance of small invertebrates
[4-6]. In fact, the 3-dimensional complex structure
provided by seagrasses represents a clear advantage
for several invertebrates, as well as for young fish, that
find refuge from predation [7]. It has been demon-
strated that the capture success of predators is gener-
ally higher over bare substrates than in seagrass
meadows and this leads settling larvae, juveniles and
adults towards coastal meadows [8]. A rich fish popu-
lation inhabits the seagrass meadows, because it is
attracted to the abundant food (i.e., small invertebrates;
[9]) and to the shelter from predators typically pro-
vided by these structured habitats. In fact, seagrass
meadows play the role of nurseries for important fish
species [10,11] that, along with decapod crustaceans
[12,13], are important consumers of secondary pro-
duction in these systems [14-16]. According to [7], the
relative value of seagrasses as predation defense is
correlated to the relative abundance of ambush-, stalk-
and chase-attack predators inhabiting seagrass and
neighboring substrata.
Several authors have investigated the structure of
the food webs in Posidonia oceanica meadows (e.g.,
[5,17-19]). However, there is still a remarkable lack of
information on the main pathways of transfer from the
plant level to the highest trophic levels [20,21]. In par-
ticular, the fate of secondary production in the food
webs of P. oceanica meadows is partially unknown.
Although fish are hypothesized to be the highest level
consumers of secondary production in seagrass
meadows [22,23] and in other environments [24], the
rate and the pathways of transfer are still uncertain.
Another important feature of Mediterranean sea-
V. Zupo et al. / Natural Science 2 (2010) 1274-1286
Copyright © 2010 SciRes. OPEN ACCESS
grass meadows is their seasonality. Such seagrasses as
P. oceanica are stable and time-persistent, but their
canopy exhibits important seasonal variations due to
the characteristic rhythm of growth [17]. These varia-
tions are also in accordance with dramatic shifts in the
amount of detritus and epiphytes available [25,26]. In
addition, seasonal differences in abundance and com-
position of associated invertebrate populations were
observed in the leaf stratum [27]. Similar variations
may be observed among differently exposed meadows.
In fact, P. oceanica beds located in areas influenced by
high hydrodynamic pressure exhibit lower abundance
of detritus and different epiphyte associations, as
compared to meadows exposed to low hydrodynamic
forces [2,5]. Due to these spatial and temporal differ-
ences in the abundance of potential prey, the general
assumption that fish represent important predators for
selected invertebrates living in the leaf stratum of sea-
grasses [1,14,16] should be confirmed by direct data.
The feeding behaviour of fish living within the leaf
canopy of three P. oceanica meadows has been inves-
tigated in the present paper, through the analysis of
their gut contents, to assess their role in the consump-
tion of secondary production in two seasons and,
therefore, the impact of fish predation [28] on inverte-
brate populations. Our major questions were: 1) Which
is the trophic role played by fish in a range of P. oce-
anica meadows? 2) Are the trophic guilds exhibited by
selected species of fish stable in space and time, or are
they adapted to spatial and seasonal variations in the
structure of the associated algal and animal communi-
ties? 3) May fish be considered the highest-level con-
sumers of secondary production in seagrass meadows?
This investigation was carried out on Posidonia oce-
anica meadows off the island of Ischia (Gulf of Naples,
Italy; Figure 1), extending from 1 to about 30 m depth.
Samples were collected at three meadows differently
exposed: 1) Lacco Ameno Bay, on the northern sector
Figure 1. Map of the sampling area and
location of the three sampling sites. LA:
Lacco Ameno; P: Channel between Is-
chia and Procida; SP: Cape S. Pancra-
of the island; 2) the channel between Ischia and the is-
land of Procida, on the eastern side of the island of Is-
-chia, and 3) off Cape San Pancrazio, on the south-east
side. Samples were collected in winter (March) and
summer (July) on P. oceanica meadows, at depths be-
tween 17 and 20 m. This depth was selected as it corre-
sponds to the “intermediate” meadow (as described by
[5]), whose animal populations can be regarded as rep-
resentative of the whole system. It is more stable than
the shallow meadow, less exposed to environmental dis-
turbances, and exhibits a higher structural complexity
than the deep meadow [5,17]. The two sampling seasons
chosen correspond, respectively, to the periods before
and after the reproduction of several species of benthic
invertebrates. We selected these periods also to point out
any difference in the diet of fish due to variations in the
availability of their prey.
Previous authors [29] investigated the methodological
bias of sampling instruments applied to the same eco-
system studied in the present paper and they determined
that skid trawls can efficiently sample the fish assem-
blage living close to the canopy. Therefore, a skid trawl
with a frame of 1.5 x 0.5 m and a mesh of 8 mm was
used, according to the technique described by [30]. Four
replicates were collected in each site around noon, both
in summer and in winter. Each replicate was obtained by
towing the skid for 5 minutes at a constant speed of 1
knot, to cover an area of about 250 m2. All fish collected
were preserved in 10% buffered formalin.
Individual fish were identified to the species level,
measured (total length), weighed (fresh weight), and
dissected for the analysis of gut contents. Gut contents
were examined under a dissecting microscope and, when
necessary, permanent slides were prepared and analysed
under a compound microscope. Each prey was identified
to the lowest possible taxonomic level and its abundance
was evaluated assigning a score from 0 to 4 (i.e., 0%,
25%, 50%, 75%, and 100% of the total gut volume, re-
spectively). Least abundant food items were pooled into
larger taxa, to obtain a matrix “species vs. food items”
for statistical analyses. The ratio between total gut con-
tent of each individual and the gut volume was indicated
by a score (from 0 to 4, as above mentioned), to quantify
gut “fullness”. This technique was used to obtain a
quantitative estimation of the whole gut content, avoid-
ing the experimental error due to the immersion in for-
malin and to the high fragmentation of some materials
Fish populations were statistically analysed to detect
variations in their composition, among replicates, sites
and seasons. Differences among individual samples were
tested by one-way analysis of variance (ANOVA). The
significance of differences among individual diets was
evaluated by t-test. The diets of the most abundant fish
V. Zupo et al. / Natural Science 2 (2010) 1274-1286
Copyright © 2010 SciRes. OPEN ACCESS
species were analysed for variation in their food sources
as a function of the sampling site and season. Gut con-
tent data were analysed by the technique described by
[18], to classify species in homogeneous trophic groups
and obtain an ordination of fish trophic groups according
to the site and the season of sampling [27]. The tech-
nique involves the calculation, for each species in each
sample, of two indices defining a trophic category, based
on average prey “type” (plant or animal) and “size” (tak-
ing into account the average size in millimetres of each
prey item). In particular, the two indices were obtained
by the following formulae:
a) Prey type index:
iii ij
TypeV CM
  (1)
b) Prey size index:
In(() /)
SizePS MM
= abundance of plant items;
= abundance of animal items;
= abundance of each considered item;
= mean prey size (measured in mm).
This technique allows for an ordination of species in
Cartesian plots showing feeding preferences, to compare
the results obtained at different sites or during different
seasons, and to simplify the understanding of complex
ecosystem food webs. In fact, the positions of species in
the 4 quarters of the plot indicate their feeding habits:
macro-herbivores are ordered in the 1st sector (upper
right), micro-herbivores in the 2nd sector (lower right),
micro-carnivores in the 3rd sector (lower left),
macro-carnivores in the 4th sector (upper left), omnivores
are close to the centre of axes. The information collected
was used to draw the main trophic relationships in the
considered system.
3.1. Fish Populations
No significant differences between the four replicates
of each sample were found (ANOVA; p<0.01). There-
fore, the specimens collected in each set of four parallel
replicates were pooled, prior to be subjected to trophic
analyses. A total of 926 individual fish, belonging to 28
species (Table 1), was sampled, identified, and analysed.
The most abundant families were Labridae (41% of all
individuals), Pomacentridae (39%), Scorpaenidae (8%)
and Serranidae (6%). The most abundant species (Fig-
ure 2) were Chromis chromis (356 ind.; 38%); Sympho-
dus ocellatus (187 ind.; 20%) and S. rostratus (134 ind.;
14%). The total number of species and individuals in
each sample varied according to the site and the season
Figure 2. Percent abundance of the most abun-
dant fish species in all samples (pooled).
Figure 3. Mean number of individuals collected
(left axis) and species richness (right axis) for
each sample. LA, Lacco Ameno; SP, S. Pancrazio;
P, Channel of Procida. The first three collections
were performed in summer, the other three in
winter. Standard deviations among the four rep-
licates are indicated by error bars.
and it was highest in Lacco Ameno in summer (Figure
The total number of species per sample varied be-
tween 7 (at the Procida channel, summer) and 16 (at
Lacco Ameno, summer). The biomass of species sam-
pled in winter was constantly higher than in summer,
with the exception of the families Pomacentridae and
Congeridae. Labridae reached a winter biomass of about
2 g m-2 (fresh weight) in the sampled meadows. The
families Labridae, Pomacentridae and Serranidae ac-
counted for 98% of the total fish biomass. Most indi-
viduals were small in comparison to the maximum size
reached by the species (Table 1). Large intra-specific
size variations were observed mainly in the samples col-
lected at Lacco Ameno.
3.2. Analysis of Gut Contents
Ninety-four food items were identified in the guts.
V. Zupo et al. / Natural Science 2 (2010) 1274-1286
Copyright © 2010 SciRes. OPEN ACCESS
Table 1. Fish species collected, total number of individuals collected in all the samples (pooled), mean
length (cm total length) and mean weight (g wet weight) of each species.
Nr. Species Total Mean Mean
nr. ind. length (cm) weight (g)
1 Chromis chromis (Linnaeus, 1758) 356 5.43 7.37
2 Symphodus ocellatus Forsskal, 1775 187 6.04 1.07
3 Symphodus rostratus (Block, 1797) 134 8.41 13.52
4 Scorpaena porcus Linnaeus, 1758 69 8.48 4.82
5 Serranus scriba (Linnaeus, 1758) 42 11.01 3.75
6 Symphodus mediterraneus (Linnaeus, 1758) 26 5.57 4.65
7 Nerophis maculatus Rafinesque, 1810 17 20.61 14.75
8 Symphodus tinca (Linnaeus, 1758) 17 12.48 1.03
9 Gobius cruentatus Gmelin, 1789 15 4.60 0.93
10 Serranus hepatus (Linnaeus, 1758) 12 6.22 10.16
11 Syngnathus acus Linnaeus, 1758 8 20.76 0.76
12 Arnoglossus kessleri Schmidt, 1915 6 5.00 2.78
13 Symphodus cinereus (Bonnaterre, 1788)6 7.73 67.20
14 Scorpaena notata Rafinesque, 1810 5 8.43 0.99
15 Apogon imberbis (Linnaeus, 1758) 4 8.08 3.52
16 Gobius geniporus Valenciennes, 18373 4.75 0.96
17 Labrus viridis Linnaeus, 1758 3 13.65 35.31
18 Mullus surmuletus Linnaeus, 1758 3 7.40 4.04
19 Conger conger (Linnaeus, 1758) 2 24.05 12.41
20 Diplodus annularis (Linnaeus, 1758) 2 12.60 3.59
21 Serranus cabrilla (Linnaeus, 1758) 2 10.01 18.83
22 Bothus podas (Delaroche, 1809) 1 4.80 1.27
23 Coris julis (Linnaeus, 1758) 1 8.80 20.87
24 Deltentosteus quadrimaculatus (Valenciennes, 1837)1 6.26 4.87
25 Gobius vittatus Vinciguerra, 1883 1 5.25 1.12
26 Spicara maena (Linnaeus, 1758) 1 10.80 14.51
27 Symphodus doderleni Jordan, 1891 1 3.90 31.37
28 Symphodus melanocercus (Risso, 1810) 1 4.80 0.49
Scarcely abundant food items were pooled into larger
taxa and a matrix containing 28 species of fish (Table 1)
and 30 food items (Table 2) was obtained. The most
abundant species, Chromis chromis, fed mainly on
plankton items, besides molluscs and decapods. In con-
trast, the two most abundant species of Labridae, Sym-
phodus ocellatus and S. rostratus, fed on a wide spec-
trum of food items shared with the whole fish population.
Their diet profiles, however, were different, since S.
ocellatus fed mainly on copepods and other crustaceans,
while S. rostratus exhibited a wider spectrum of prefer-
ences, including plathelminthes, small crustaceans,
natantia decapods, and Posidonia tissues. Another im-
portant species of Labridae, Symphodus mediterraneus,
showed a narrower dietary spectrum (21 items) and fed
preferentially on brown Posidonia tissues, copepods,
reptantia decapods, and other animal items. Serranus
scriba, S. cabrilla and Scorpaena porcus, among the
other abundant species, fed preferentially on natantia and
reptantia decapods, but they exhibited a wide dietary
spectrum, including Posidonia tissues, amphipods, and
other animal items.
The ordination of species according to the “Type” and
“Size” indices [18] indicated that the fish community
plays essentially a macro-carnivore trophic role (Figure
4): species were all ordered in the 4th sector, in a com-
pact cluster. An exception was represented by Coris julis
and Spicara maena, exhibiting a "microphagous" feed-
ing pattern, and Scorpaena notata and Symphodus ciner-
eus, clustered towards a position indicating herbivorous
V. Zupo et al. / Natural Science 2 (2010) 1274-1286
Copyright © 2010 SciRes. OPEN ACCESS
Table 2. Food items taken into account in the
present investigation and their average abun-
dance (% of gut contents) in all samples.
Prey item % abundance
1) Copepods 12.93
2) Gammarid amphipods 10.06
3) Natantia decapods 9.26
4) Unidentified animal tissues 8.57
5) Reptantia decapods 6.45
6) Brown tissues of Posidonia 6.37
7) Ostracods 6.23
8) Unidentified crustaceans 6.01
9) Isopods 4.29
10) Caprellid amphipods 3.93
11) Fish 3.81
12) Macroalgae 3.19
13) Unidentified decapods 2.5
14) Plathelminthes 2.37
15) Mysidaceans 2.32
16) Nematodes 2.22
17) Tanaidacea 1.87
18) Polychaetes 1.54
19) Gastropod molluscs 1.12
20) Unidentified vegetal tissues 0.79
21) Eggs 0.78
22) Acarids 0.66
23) Foraminiferans 0.64
24) Microalgae 0.59
25) Sipunculids 0.4
26) Pantopods 0.4
27) Cumaceans 0.29
28) Unidentified molluscs 0.17
29) Bivalve molluscs 0.16
30) Echinoderms 0.06
feeding habit. Chromis chromis occupied a polar posi-
tion, also indicating a microcarnivorous diet. The most
abundant labridae, S. ocellatus and S. rostratus, were in a
central position in the cluster. Besides the above excep-
tions, all the Scorpaenidae and Serranidae were grouped
in a central compact sub-cluster.
Seasonal variations in the feeding habits of some spe-
cies were observed (Figure 5). In summer Labrus viridis
and S. cinereus exhibited a more “herbivorous” habit
than in winter. In winter S. ocellatus preyed almost en-
tirely on animals, while in summer it fed mainly on plant
matter. S. rostratus did not change its feeding prefer-
ences (plant or animal) between the two seasons. No
variations in the “Size” index were observed between the
two seasons for any species, but the dietary composition
changed. The total number of prey items of S. ocellatus
Figure 4. Ordination in the “Type-Size” space of the species
collected in all the samples. The horizontal axis discriminates
the “type” of diet (based on the abundance of plant or animal
prey items); the vertical axis discriminates the “size” of diet
(based on small or large prey items). Circles indicate the posi-
tion of each species of fish (the most abundant are specified).
Figure 5. Ordination in the “Type-Size” space of the species
according to the season of sampling (a, summer; b, winter).
The horizontal axis discriminates the “type” of diet (based on
the abundance of plant or animal prey items); the vertical axis
discriminates the “size” of diet (based on small or large prey
items). Circles indicate the position of each species of fish (the
most abundant are specified).
V. Zupo et al. / Natural Science 2 (2010) 1274-1286
Copyright © 2010 SciRes. OPEN ACCESS
significantly changed according to the season. In fact S.
ocellatus fed on 24 prey items in summer, and 20 in
winter, when its diet was mainly based on copepods
(32% of gut contents).
In contrast, the total number of prey items of S. ros-
tratus was constant (24) in the two seasons and no sig-
nificant differences were observed in the food composi-
Other species, such as Serranus scriba and Scorpaena
porcus, exhibited a comparable reduction of plant items
in winter, and different feeding preferences in the two
seasons, as revealed by the “Type-Size” ordinations.
The samples obtained at Lacco Ameno (Figure 6(a)) and
San Pancrazio (Figure 6(c)) clustered according to prey
size, more tightly in respect to the Channel of Procida
(Figure 6(b)). In particular, such species as Mullus sur
Figure 6. Ordination in the “Type-Size” space of the species
according to the site of sampling (a, Lacco Ameno; b, Procida;
c, S. Pancrazio). The horizontal axis discriminates the “type”
of diet (based on the abundance of plant or animal prey items);
the vertical axis discriminates the “size” of diet (based on
small or large prey items). Circles indicate the position of each
species of fish (the most abundant are specified).
muletus, Serranus scriba, and Scorpaena porcus, occu-
pied a higher position along the “Size” axis in the sam-
ples of the Channel of Procida, indicating a feeding habit
with a stronger “macrophagous” character. No signifi-
cant variations in the diet were detected by ANOVA be-
tween Lacco Ameno and the other two sites.
The analysis of diets indicated that the main prey
items of fish (Table 2), were copepods (12,93% of their
gut contents, on average), gammarid amphipods
(10,06%), Natantia decapods (about 9%) and, besides
unidentified animal tissues (8,57%), Posidonia tissues
(6,37%) and ostracods (6,23%). Seasonal variations of
the diet were observed (Table 3) at lower taxonomic
levels. The basic structure of the fish food webs was
traced based on previous data (Figure 7) and the abun-
dances (volumes occupied in the gut contents of fish) of
each item in the food webs were organised to permit a
comparison of their relative importance. The most
abundant items (in terms of volume occupied in the guts)
were copepods, amphipods, decapods and other crusta-
The skid trawl, as demonstrated by [29], is a suitable
sampling tool to obtain a representative picture of the
fish fauna living within the Posidonia oceanica mead-
ows, allowing for the study of the upper levels of local
food webs [30,31]. Other sampling methods, however,
may complete the information on the fish assemblage of
meadows, in particular on upper water dwellers, feeding
mainly on planktonic micro-crustaceans or other fish
[21,29]. The efficiency of the trawl was higher in winter,
when the canopy was lower. The investigated meadows
were characterised by benthic families of fish (Labridae,
Pomacentridae, Scorpaenidae, Sygnathidae, Serranidae)
although a few individuals were found that belonged to
families with good swimming capabilities (e.g., Spari-
dae). The number of species collected during this inves-
tigation was lower than the number of species found in
French meadows of P. oceanica meadows using an iden-
tical sampling technique (28 as compared to 49 species;
[33]). The difference may be due to a higher fishing
pressure characterising the meadows investigated in the
present paper, in accordance with the results of previous
studies [29].
Fresh weight estimates showed the importance of the
main three families, i.e., Labridae, Pomacentridae and
Scorpaenidae. In fact, they accounted for 99.4 % of the
total fish biomass sampled in summer and for 93.7% of
the total fish biomass sampled in winter (98% of the
total fish biomass throughout the year).
The high fish biomass collected in winter was not
correlated with individual fish weight. It was due to a
V. Zupo et al. / Natural Science 2 (2010) 1274-1286
Copyright © 2010 SciRes. OPEN ACCESS
Table 3. Prey found in the gut contents of the most abundant species of fish collected. A grey square
indicates the presence of each prey in summer (S) and/or winter (W) samples.
Fish SW
Apogon imberbis Eualus occultus (Lebour, 1936)
Processa acutirostris Nouvel & Holthuis, 1957
Chromis chromis Hippolyte sp. Leach, 1814
Jujubinus sp. Monterosato, 1884
Liljeborgia dellavallei Stebbing, 1906
Siriella clausii G.O.Sars, 1876
Synisoma appendiculatum (Risso, 1816)
Scorpaena notata Cymodoce hanseni Dumay, 1972
Galathea intermedia Lilljeborg, 1851
Hippolyte sp. Leach, 1814
Scorpaena porcus Apherusa vexatrix Krapp-Schickel, 1979
Cheirocratus sundevallii (Rathke, 1843)
Cymodoce hanseni Dumay, 1972
Cymodoce hanseni juv. Dumay, 1972
Eualus occultus (Lebour, 1936)
Eualus pusiolus (Kroyer, 1841)
Eualus sp. Thallwitz, 1891
Galathea bolivari Zariquiey A., 1950
Hippolyte inermis Leach, 1815
Hyale carinata (Bate, 1862)
Inachus thoracicus (Roux, 1830)
Liocarcinus arcuatus (Leach, 1814)
Liocarcinus pusillus (Leach, 1815)
Lysmata seticaudata (Risso, 1816)
Macropodia sp. Leach, 1814
Munida intermedia A. Milne-Edwards & Bouvier,1899
Palaemon sp. Weber, 1795
Platynereis dumerilii (Audouin & Milne-Edwards, 1833)
Processa acutirostris Nouvel & Holthuis, 1957
Synisoma appendiculatum (Risso, 1816)
Thoralus cranchii (Leach, 1817)
Serranus hepatus Amphiura chiajei Forbes, 1843
Clibanarius erythropus (Latreille, 1818)
Liocarcinus arcuatus (Leach, 1814)
Phtisica marina Slabber, 1769
Processa sp. Leach, 1815
Serranus scriba Clibanarius erythropus (Latreille, 1818)
Galathea bolivari Zariquiey A., 1950
Leptomysis mediterranea G.O.Sars, 1877
Table 3. (Continued)
Liljeborgia dellavallei Stebbing, 1906
Liocarcinus arcuatus (Leach, 1814)
Parasiphaea sivado Risso, 1816
Processa acutirostris Nouvel & Holthuis, 1957
V. Zupo et al. / Natural Science 2 (2010) 1274-1286
Copyright © 2010 SciRes. OPEN ACCESS
Processa canaliculata Leach, 1815
Thoralus cranchii (Leach, 1817)
Vargula mediterranea Costa, 1845
Symphodus mediterraneus Achelia echinata Hodge, 1864
Galathea sp. Fabricius, 1793
Platynereis dumerilii (Aud.&M.Edwards, 1833)
Symphodus ocellatus Callipallene brevirostris (Johnston, 1837)
Gnathia sp. Leach, 1814
Nymphon sp. Fabricius, 1794
Parategastes sphaericus Claus, 1863
Praniza of Gnathia sp. Leach, 1814
Synisoma appendiculatum (Risso, 1816)
Symphodus rostratus Alpheus dentipes Guérin, 1832
Athanas sp. Leach, 1814
Cymodoce sp. Leach, 1814
Galathea bolivari Zariquiey A., 1950
Galathea sp. Fabricius, 1793
Gnathia sp. Leach, 1814
Hippolyte sp. Leach, 1814
Inachus thoracicus (Roux, 1830)
Munida intermedia A. Milne-Edwards & Bouvier,1899
Praniza of Gnathia sp.
Processa macrophthalma Nouvel & Holthuis,1957
Siriella clausii G.O.Sars, 1876
Synisoma appendiculatum (Risso, 1816)
Symphodus tinca Cymodoce sp. Leach, 1814
Galathea sp. Fabricius, 1793
Harmothoe sp. Kinberg, 1855
Hippolyte inermis Leach, 1815
Laetmonice hystrix (Savigny, 1820)
Lepadogaster candollei Risso, 1810
Paranthura nigropunctata (Lucas, 1849)
Pontogenia chrysocoma (Baird, 1865)
Synisoma appendiculatum (Risso, 1816)
Syngnathus acus Ampelisca rubella A.Costa, 1864
Anapagurus laevis (Bell, 1846)
Athanas nitescens (Leach, 1814)
high numerical abundance; more individuals were
caught in winter, probably due to the greater winter effi-
ciency of the trawl in the lower canopy or to lower tro-
phic resources of surrounding benthic systems [34].
Differences in the abundance of species at the three sites
were demonstrated to be not significant, and several
species were present with a low number of individuals
and low biomass Therefore we focused our investigation
upon the most abundant species, i.e., the foremost 14
reported in Table 1. Most of the sampled fish species are
carnivorous and should represent the top consumers
within the meadow [7,33]. However, seasonal variations
in the diet (plant or animal) of some species were de-
tected in the present investigation.
The genus Symphodus was the most abundant, ac-
counting for more than 40% of the total fish population.
V. Zupo et al. / Natural Science 2 (2010) 1274-1286
Copyright © 2010 SciRes. OPEN ACCESS
Figure 7. Pathways of matter transfer (volumes of gut contents) in the fish food webs, based on the
data of the present paper (solid links between secondary producers and fish) and literature data
(dotted links between primary producers and secondary producers; see text). Only vertical links
were taken into account, to highlight the role of fish predation. The fish compartment is mainly
represented by Labridae, Pomacentridae, Scorpaenidae and Serranidae. Numbers in parenthesis in-
dicate the average volumes occupied by each item in the guts.
The diet of species in this genus was based on vagile
organisms of the leaf stratum, grazers of the epiphyte
layer. Therefore the genus Symphodus represents one of
the pathways from secondary producers within the leaf-
stratum to the export chain. The large spectrum of prey
items found in the guts of the most abundant species,
Symphodus ocellatus and S. rostratus, indicates high
trophic adaptability, and this may be responsible for
theirsuccess within the studied meadows, as documented
by their abundance. In contrast, the diet of the most
abundant species, Chromis chromis, was based on a few
items, scarcely present in the guts of other fish. There-
fore, this species has the advantage to use a rich, unex-
ploited microphagous trophic niche. Other abundant
species, such as Scorpaena porcus and Serranus scriba,
fed almost exclusively on abundant [5] items in the
meadow (e.g., decapod crustaceans and gammarid am-
phipods). Symphodus rostratus, S. porcus and S. scriba
were efficient predators of decapod crustaceans, since
deca pods accounted for more than 30% of their gut
volume. The abundance of these three species of fish
may explain the high predation pressure observed on
various decapod populations [35,36].
The diet of S. ocellatus and S. mediterraneus, in con-
trast, was based on smaller crustaceans (copepods and
amphipods) accounting for more than 30% of their gut
volume. The abundance of brown tissues of Posidonia in
the guts of these species indicates that it is not an occa-
sional item, although the actual trophic role of leaf de-
tritus is unclear [37]. It could be used per se, or ingested
to digest bacteria and small prey present on its surface
The ordination of species in the “Type-Size” plots
confirmed that fish play essentially a macro-carnivore
role in the meadow food webs. Given the low rate of
recycling (fish represented less than 4% of prey in the
gut contents), it may be assumed that most of the bio-
mass produced within the system is exported to other
coastal systems through predation by fish swimming
over the canopy, or lost through fishing activities [6].
The main variations were observed in the “Type” index,
indicating that some species, such as Symphodus ciner-
eus and Labrus viridis, can adapt their diets according to
the availability of animal or plant items, while the aver-
age size of their prey did not vary. However, the diets of
the most abundant species exhibited slight seasonal
variations. The prey taxa consumed by most fish were
abundant throughout the year [5], although variations of
prey at a lower taxonomic level (i.e., species) were de-
tected (Table 3).
The three dominant species of fish showed seasonal
variations of prey at species level and some prey-species,
V. Zupo et al. / Natural Science 2 (2010) 1274-1286
Copyright © 2010 SciRes. OPEN ACCESS
abundant in the gut contents in summer (such as Hip-
polyte inermis) were absent in winter (Table 3), accord-
ing to their known [35] seasonal patterns of abundance
in the meadows.
They were replaced in the diet by prey-species with a
similar shape and size, such as Eualus sp. and Processa
acutirostris. The seasonality in the prey availability was
also demonstrated by the fact that such fish as S. ocella-
tus, S. rostratus, and S. porcus, showed a larger diet
spectrum in summer than in winter.
The ordination of species in the “Type-Size” space
according to sites indicated that fish sampled off the
island of Procida used prey characterised by a broader
spectrum of sizes, as compared to the other two mead-
ows. In fact, the maximum “Size” index reached by fish
sampled at Lacco Ameno and San Pancrazio was about 1,
while some species sampled at Procida, such as Mullus
surmuletus, S. scriba and S. porcus, reached higher Size
index scores. The comparable size of these fish species
at the three sites suggests that differences shown in the
Size index are dependent on prey availability.
A diagram of the main pathways of transfer, from pri-
mary producers to the top-level predators, can be drawn
for the investigated P. oceanica meadows, based on the
data of the present work and literature information on
the feeding habits of the most abundant grazers. The guts
contained mainly small invertebrates, typical of the leaf
stratum, feeding on microphyta, macrophyta, and Posi-
donia detritus [12,40-44]. Taking into account the abun-
dance (% of gut volume) of each food item in the two
seasons, 12.9% of prey (in terms of gut volume) was
represented by copepods, feeding, in their turn, mainly
on diatoms and bacteria [34,41,45,46]. Gammarid am-
phipods accounted for 10.0% of fish prey and they feed
mainly on micro-algae [47-51]. Reptantia decapods ac-
counted for 6.4% of the fish prey and they feed mainly
on Posidonia detritus and macrophyta [18], although
horizontal links should be taken into account [52]. In
fact, reptantia decapods also feed on other secondary
producers, such as natantia decapods, amphipods, cope-
pods, molluscs, tanaidacea, isopods, sipunculids, poly-
chaetes [19,43,53,54]. Natantia deca pods accounted for
9.2% of the fish prey and they feed mainly on mi-
cro-algae and small organisms of the leaf stratum (am-
phipods, copepods, acarids; [5,35]), although horizontal
links should be taken into account and also for this taxon
[43,52,55,56]. Ostracods accounted for 6.2% of fish prey
and they feed mainly on micro-algae [26,34]. Other
small crustaceans accounted for 6.1% of the fish prey
and they feed mainly on nematodes, copepods, and cili-
ates [57]. Isopods accounted for 4.3% of the fish prey
and they mainly feed on micro-algae and detritus [58]. A
low recycling rate in the fish compartment must be taken
into account, since it was calculated that 3.8% of fish
prey is represented by teleosts. Scorpaenidae, Serranidae,
Pomacentridae and Congridae were the main fish feed-
Our data indicated a pathway of transfer from Posido-
nia detritus, macrophyta and microphyta (as primary
producers) to crustacean decapods, copepods, ostracods,
and gammarid amphipods (as secondary producers) to
fish (as consumers), mainly represented by Labridae,
Pomacentridae, Scorpaenidae, and Serranidae. The rate
of recycling through these families is low (about 4%).
Crustacean decapods represent another important loop of
biomass recycling, since they can feed also on the other
secondary producers described above [14,18]. Therefore,
besides natural mortality, the biomass stocked in the fish
compartment (in terms of volumes) may be exported to
other systems by means of predation by other fish [33],
non resident in the meadows and characterised by higher
swimming capabilities, such as Sparidae, larger Serrani-
dae, and Congridae.
A comparison with studies in other seagrasses
[10,13,20,59,60,61] and different sites of the Mediterra-
nean [33] allows for detecting a general trend of fish
assemblages, with respect to the feeding behaviour of
dominant species. They generally show a clear prefer-
ence for epibenthic fauna and extensively feed on crusta-
ceans. Only few herbivorous and herbivorous-detritivorous
species were detected in P. oceanica meadows, despite
the large abundance of plant material available. In con-
trast, herbivorous and omnivorous fish are common in
other seagrass communities [28,60,61,62], characterised
by a larger variety of trophic levels. Most species were
carnivorous, both macrophagic and microphagic, in ac-
cordance with the results obtained in French P. oceanica
meadows [33]. The only herbivorous fish, well known in
Mediterranean seagrass meadows, is Sarpa salpa (L.)
[33]; however this species is generally restricted to shal-
low meadows (less than 10 m depth), characterised by a
higher abundance of plant epiphytes. Therefore, it did
not occur in the depth range investigated in the present
paper and its feeding impact scarcely influences the food
webs of deeper meadows, exhibiting a higher stability
and complexity.
Labride are consistently dominant in Mediterranean P.
oceanica meadows [22] and they feed on a broad spec-
trum of prey items, with a preference for crustaceans
(mainly amphipods and decapods). However, they can
adapt their diet according to the site and the time of
sampling. In fact, our analyses indicated seasonal
changes in the diet of some species and a lower abun-
dance of molluscs in their gut contents, as compared to
the results of [33]. Gastropod molluscs were mainly
consumed by Chromis chromis, the most abundant spe-
cies. In contrast, Labridae may be considered as
mesophagic carnivores [33] feeding on copepods, gam-
V. Zupo et al. / Natural Science 2 (2010) 1274-1286
Copyright © 2010 SciRes. OPEN ACCESS
marid amphipods, decapods, ostracods and other crusta-
ceans, as well as molluscs. Decapods and other small
crustaceans of the leaf stratum were demonstrated to be
keystone items in the fish food webs [36], transferring
biomass from the primary producers to the top predators.
This trend appears to be a general feature of seagrass
meadows [60,63], since it is in accordance with the re-
sults obtained in other seagrass ecosystems, both tem-
perate and tropical.
We are indebted to P. Francour for the collection of samples in Ischia.
We are grateful to M.C. Gambi, M.B. Scipione and M. Lorenti for their
assistance in the determination of species. D. Stübing was supported by
a COMETT fellowship, Europäischer Praktikantenaustausch. Mrs R.
Messina revised the English text.
[1] Khoury, C. (1984) Ethologies alimentaires de quelques
espèces de poissons de l’herbier de Posidonies du Parc
National de Port-Cros. International workshop on
Posidonia oceanica beds. In: Boudouresque C.F. et al.
Eds., GIS Posidonie, Marseilles, France, 1, 335-347.
[2] Edgar, G.J. and Shaw, C. (1993) Relationships between
sediments, seagrasses, benthic invertebrates and fishes in
shallow marine habitats off South-Western Australia.
Proceedings of the fifth International marine Biological
Workshop: the flora and fauna of Rottnest Island,
Western Australia, In: Wells, F.E. and Walker, D.I. Eds.,
Western Australian Museum, Perth, Australia, 429-442.
[3] Minello, T.J. (1993) Chronographic tethering—a
technique for measuring prey survival time and testing
predation pressure in aquatic habitats. Marine Ecology
Progress Series, 101, 99-104.
[4] Bell, J.D. and Westoby, M. (1986) Abundance of
macrofauna in dense seagrass is due to habitat preference,
not predation. Oecologia, 68, 205-209.
[5] Gambi, M.C., Lorenti, M., Russo, G.F., Scipione, M.B.
and Zupo, V. (1992) Depth and seasonal distribution of
some groups of vagile fauna of Posidonia oceanica leaf
stratum: structural and trophic analyses. P.S.Z.N.I.:
Marine Ecology, 13, 17-39.
[6] Valentine, J.F., Heck, K.L., Blackmon, D., Goecker,
M.E., Christian, J., Kroutil, R.M., Peterson, B.J.,
Vanderklift, M.A., Kirsch, K.D. and Beck, M. (2008)
Exploited species impacts on trophic linkages along
reef-seagrass interfaces in the Florida keys. Journal of
Ecology Applied, 18, 1501-1515.
[7] Schultz, S.T., Kruschel, C. and Bakran-Petricioli, T.
(2009) Influence of seagrass meadows on predator–prey
habitat segregation in an Adriatic lagoon. Marine
Ecology Progress Series, 374, 85-99.
[8] Heck, K.L. and Orth, L.M. (1980) Seagrass habitats: The
role of habitat complexity, competition and predation in
structuring associated fish and motile macroinvertebrate
assemblages. In: Kennedy V.S. Ed., Estuarine
perspectives, Academic Press, New York, 449-464.
[9] Connolly, R.M. (1994a) The role of seagrass as preferred
habitat for juvenile Sillaginodes punctata (Cuv and Val)
(Sillaginidae, Pisces)habitat selection or feeding.
Journal of Experimental Marine Biology and Ecology,
180, 39-47.
[10] Carr, W.E.S. and Adams, C.A. (1973) Food habits of
juvenile marine fishes occupying seagrass beds in the
estuarine zone near Crystal River, Florida. Transactions
of the American Fisheries Society, 102, 511-540.
[11] Middleton, M.J., Bell, J.D., Burchmore, J.J., Pollard, D.A.
and Pease, B.C. (1984) Structural differences in the fish
communities of Zostera capricorni and Posidonia
australis seagrass meadows in Botany Bay, New South
Wales. Aquatic Botany, 18, 89-109.
[12] Zupo, V. (2001) Influence of diet on sex differentiation
of Hippolyte inermis Leach (Decapoda: Natantia) in the
field. Hydrobiologia, 449, 131-140.
[13] Burfeind, D.D., Tibbetts, I.R. and Udy, J.W. (2009)
Habitat preference of three common fishes for seagrass,
Caulerpa taxifolia, and unvegetated substrate in Moreton
Bay, Australia. Environ. The Journal of Fish Biology, 84,
[14] Pollard, D.A. (1984) A review of ecological studies on
seagrass-fish communities, with particular reference to
recent studies in Australia. Aquatic Botany, 18, 3-42.
[15] Robertson, A.I. (1984) Trophic interactions between the
fish fauna and macrobenthos of an eelgrass community
in Western Port, Victoria. Aquatic Botany, 18, 135-153.
[16] Baird, D., Asmus, H. and Asmus, R. (2007) Trophic
dynamics of eight intertidal communities of the
Sylt-Rømø Bight ecosystem, northern Wadden Sea.
Marine Ecology Progress Series, 351, 25-41.
[17] Mazzella, L., Buia, M.C., Gambi, M.C., Lorenti, M.,
Russo, G.F., Scipione, M.B. and Zupo, V. (1992)
Plant-animal trophic relationships in the Posidonia
oceanica ecosystem of the Mediterranean Sea: A review.
Plant-Animal Interactions in the Marine Benthos. In:
John D.M. et al. Eds., Systematics Association, Special,
Clarendon Press, Oxford, UK, N6, 165-187.
[18] Zupo, V. (1993) The use of feeding indices for the study
of food webs: an application to a Posidonia oceanica
ecosystem. Coenoses, 8, 85-95.
[19] Gloeckner, D.R. and Luczkovich, J.J. (2008)
Experimental assessment of trophic impacts from a
network model of a seagrass ecosystem: Direct and
indirect effects of gulf flounder, spot and pinfish on
benthic polychaetes. Journal of Experimental Marine
Biology and Ecology, 357, 109-120.
[20] Brook, I.M. (1977) Trophic relationships in a seagrass
community (Thalassia testudinum) in Card Sound,
Florida. Fish diets in relation to macrobenthic and cryptic
faunal abundance. Transactions of the American
Fisheries Society, 106, 219-229.
[21] Burchmore, J.J., Pollard, D.A. and Bell, J.D. (1984)
Community structure and trophic relationships of the fish
fauna of an estuarine Posidonia australis seagrass habitat
in Port Hacking, New South Wales. Aquatic Botany, 18,
[22] Bell, J.D. and Harmelin-Vivien, M.L. (1982) Fish fauna
of French Mediterranean Posidonia oceanica seagrass
meadows. I-Community structure. Téthys, 10, 337-347.
V. Zupo et al. / Natural Science 2 (2010) 1274-1286
Copyright © 2010 SciRes. OPEN ACCESS
[23] Connolly, R.M. (1994b) Removal of segrass canopy:
effects on small fish and their prey. Journal of
Experimental Marine Biology and Ecology, 184, 99-110.
[24] Kemp, S.J. (2008) Autecological effects of habitat
alteration: trophic changes in mangrove marsh fish as a
consequence of marsh impoundment. Marine Ecology
Progress Series, 371, 233-242.
[25] Velimirov, B., Ott, J.A. and Novak, R. (1981)
Microorganisms on macrophyte debris: Biodegradation
and its implication in the food web. Kieler Meeresforsch.
Sonder, 5, 333-344.
[26] Van Montfrans, J., Wetzel, R.L. and Orth, R.J. (1984)
Epiphyte-grazers relationships in seagrass meadows:
Consequences for seagrass growth and production.
Estuaries, 7, 289-309.
[27] Zupo, V. (1990) The food web of Posidonia oceanica
beds around the island of Ischia (Gulf of Naples, Italy):
A new trophic index. Rapports et Proces Verbaux des
Reunions-Commission Internationale pour l'Exploration
Scientifique de la Mèr Méditerranee, 32, 16-16.
[28] Bologna, P.A.X. (2007) Impact of differential predation
potential on eelgrass (Zostera marina) faunal community
structure. Aquatic Botany, 41, 221-229.
[29] Harmelin-Vivien, M.L. and Francour, P. (1992) Trawling
or visual censuses? Methodological bias in the
assessment of fish populations in seagrass beds.
P.S.Z.N.I.: Marine Ecology, 13, 41-51.
[30] Harmelin-Vivien, M.L. (1981) Description d’un petit
chalut à perche pour récolter la faune vagile des herbiers
de Posidonies. Rapports et Proces Verbaux des
Reunions-Commission Internationale pour l'Exploration
Scientifique de la Mèr Méditerranee, 27, 199-200.
[31] Chessa, L.A., Fresi, E. and Soggiu, L. (1982) Primi dati
sulla rete trofica dei consumatori in una prateria di
Posidonia oceanica (L.) Delile. Bollettino del Museo
Istituto di Biologia Università di Genova, 50, 156-161.
[32] Hansson, S. (1998) Methods of studying fish feeding:
Acomment. Canadian Journal of Fisheries and Aquatic
Sciences, 55, 2706-2707.
[33] Bell, J.D. and Harmelin-Vivien, M.L. (1983) Fish fauna
of French Mediterranean Posidonia oceanica seagrass
meadows. II - Feeding habits. Téthys, 11, 1-14.
[34] Montagna, P.A., Blanchard, G.F. and Dinet, A. (1995)
Effect of production and biomass of intertidal
microphytobenthos on meiofaunal grazing rates. Journal
of Experimental Marine Biology and Ecology, 185,
[35] Zupo, V. (1994) Strategies of sexual inversion in
Hippolyte inermis Leach (Crustacea, Decapoda) from a
Mediterranean seagrass meadow. Journal of
Experimental Marine Biology and Ecology, 178,
[36] Zupo, V. (2006) Decapod associations from “Banco di
Santa Croce” (Bay of Naples): A key pathway in local
food webs. Biologia Marina Mediterranea, 13(1),
[37] Lawrence, J.M., Boudouresque, C.F. and Maggiore, F.
(1989) Proximate constituents, biomass, and energy in
Posidonia oceanica (Potamogetonaceae). P.S.Z.N.I.:
Marine Ecology, 10, 263-270.
[38] Cuomo, V., Vanzanella, F., Fresi, E., Mazzella, L. and
Scipione, M.B. (1982) Microflora delle fanerogame
dell’isola d’Ischia: Posidonia oceanica (L.) Delile e
Cymodocea nodosa (Ucria) Aschers. Bollettino del
Museo Istituto di Biologia Università di Genova, 50,
[39] Kitting, C.L., Fry, B. and Morgan, M.D. (1984)
Detection of inconspicuous epiphytic algae supporting
food webs in seagrass meadows. Oecologia, 62, 145-149.
[40] Lorenti, M. and Fresi, E. (1983) Grazing of Idotea
baltica basteri on Posidonia oceanica: Preliminary
observations. Rapports et Proces Verbaux des
Reunions-Commission Internationale pour l'Exploration
Scientifique de la Mèr Méditerranee, 28, 147-148.
[41] Orth, R.J. and Van Montfrans, J. (1984)
Epiphyte-seagrass relationships with an emphasis on the
role of micrograzing: a review. Aquatic Botany, 18,
[42] Bedford, A.P. and Moore, P.G. (1985) Macrofaunal
involvement in the sublittoral decay of kelp debris: the
polychaete Platynereis dumerilii (Audouin and
Milne-Edwards) (Annelida: Polychaeta). Estuarine,
Coastal and Shelf Science, 20, 117-134.
[43] Zupo, V. and Fresi, E. (1985) A study on the food web of
the Posidonia oceanica (L.) Delile ecosystem: Analysis
of the gut contents of decapod crustaceans. Rapports et
Proces Verbaux des Reunions-Commission Inter-
nationale pour l'Exploration Scientifique de la Mèr
Méditerranee, 29, 189-192.
[44] Mazzella, L. and Russo, G.F. (1989) Grazing effect of
two Gibbula species (Mollusca, Archaeogastropoda) on
the epiphytic community of Posidonia oceanica leaves.
Aquatic Botany, 35, 357-373.
[45] Barr, M.W. (1969) Culturing the marine harpacticoid
copepod Tisbe furcata (Baird 1837). Crustaceana, 16,
[46] Nassogne, A. (1970) Influence of food organisms on the
development and culture of pelagic copepods.
Helgolander Wissenschaftliche Meeresunter-suchungen,
20, 333-345.
[47] Howard, R.K. (1982) Impact of feeding activities of
epibenthic amphipods on surface-fouling of eelgrass
leaves. Aquatic Botany, 14, 91-97.
[48] Hay, M.E., Duffy, J.E., Pfister, C.A. and Fenical, W.
(1987) Chemical defenses against different marine
herbivores: Are amphipods insect equivalent? Ecology,
68, 1567-1580.
[49] Scipione, M.B. (1989). Comportamento trofico dei
crostacei anfipodi in alcuni sistemi bentonici costieri.
Oebalia, 15, 249-260.
[50] Lorenti, M. and Scipione, M.B. (1990) Relationships
between trophic structure and diel migrations of isopods
and amphipods in a Posidonia oceanica bed of the Island
of Ischia. Rapports et Proces Verbaux des Reunions-
Commission Internationale pour l'Exploration Scientifique
de la Mèr Méditerranee, 2, 17-17.
[51] Scipione, M.B. and Mazzella, L. (1992) Epiphytic
diatoms in the diet of crustacean amphipods of Posidonia
oceanica leaf stratum. Oebalia, 17, 409-412.
[52] Nelson, W.G. (1981a) The role of predation by decapod
crustaceans in seagrass ecosystems. Kieler Meere-
sforschung Sonderheim, 5, 529-536,
V. Zupo et al. / Natural Science 2 (2010) 1274-1286
Copyright © 2010 SciRes. OPEN ACCESS
[53] Nelson, W.G. (1981b). Experimental studies of decapod
and fish predation on seagrass macrobenthos. Marine
Ecology Progress Series, 5, 141-149,
[54] Chessa, L.A., Scardi, M., Fresi, E. and Saba, S. (1989b)
Consumers in Posidonia oceanica beds: 2. Galathea
squamifera Leach (Decapoda, Anomura). II International
workshop on Posidonia beds. In: Boudouresque, C.F. et
al. Eds., GIS Posidonie, Marseilles, France, 2, 251-256.
[55] Bell, S.S. and Coull, B.C. (1978) Field evidence that
shrimp predation regulates meiofauna. Oecologia, 35,
[56] Chessa, L.A., Scardi, M., Fresi, E. and Russu, P. (1989a)
Consumers Posidonia oceanica beds: 1. Processa edulis
(Risso), (Decapoda, Caridea). In: II International
workshop on Posidonia beds. In: Boudouresque, C.F. et
al Eds., GIS Posidonie, Marseilles, France, 2, 243-250.
[57] Ambler, J.W., Alcalaherrera, J., Burke, R. (1994)
Trophic roles of particle feeders and detritus in a
mangrove island prop root ecosystem. Hydrobiologia,
293, 437-446.
[58] Klumpp, D.W., Howard, R.K. and Pollard, D.A. (1989)
Trophodynamics and nutritional ecology of seagrass
communities. Biology of seagrasses, 2. In: Larkum,
A.W.D. et al. Eds., Elsevier, Amsterdam, 394-457.
[59] Randall, J.E. (1965) Grazing effect on seagrass by
herbivorous reef fishes in the West Indies. Ecology, 46,
[60] Adams, S.M. (1976) Feeding ecology of eelgrass fish
communities. Transactions of the American Fisheries
Society, 105, 514-519.
[61] Bell, J.D., Burchmore, J.J. and Pollard, D.A. (1978)
Feeding ecology of three sympatric species of leather
jackets (Pisces: Monacanthidae) from a Posidonia
seagrass habitat in New South Wales. Austr. Journal of
marine and freshwater research, 29, 631-643.
[62] Kikuchi, T. (1966) An ecological study on animal
communities of the Zostera marina belt in Tomioka Bay,
Amakusa, Kyushu. Publ. Amakusa. Marine Biological
Laboratory, 1, 1-106.
[63] Zupo, V. and Nelson, W.G. (1999) Factors influencing the
association patterns of Hippolyte zoostericola and Pa-
laemonetes intermedius (Decapoda: Natantia) with sea-
grasses of the Indian River Lagoon, Florida. Marine Bi-
ology, 134, 181-190.