SHORT-TERM INVESTIGATION OF THE FISH COMMUNITY IN MALI STON BAY RESERVATION,
CROATIA, SOUTHERN ADRIATIC
Pero Tutman*, Nikša Glavic, Valter Kožul, Boško Skaramuca
Institute of Oceanography and Fisheries, Laboratory for Ecology and Aquaculture, Dubrovnik, Croatia - * pero.tutman@mailcity.com
Abstract
A short-term study of the coastal fish community was conducted from May till August 2003 in the special reservate in Mali Ston Bay
(southern Adriatic, Croatia), using a 25 m long beach seine. A total of 4038 fish specimens, belonging to 14 families and 28 species were
caught. Atherinidae (88,18%) dominated the catch: Atherina boyeri(81,87%) was the most numerous, while A. hepsetus(6,31%), Gobius
genioporus(2,15%), Mullus barbatus(1,95%) and M. surmuletus(1,11%) comprised 11,52% in total. The remainingspecies contributed
less than 0,3% of the catch. Most species were present as juveniles. The overall value of richness (D) was 3,25, diversity (H) values were
0,94 and evenness (J) was 0,11. Our preliminary results provide a contribution to the knowledge of the fish assemblage of the Mali Ston
Bay.
Key words: fish, biodiversity, Mali Ston Bay, Adriatic
Rapp. Comm. int. Mer Médit., 37,2004
451
Introduction
Mali Ston Bay is an unpolluted area suitable for the cultivation of
the European oyster and Mediterranean mussel. The tradition of oys-
ter and mussel farming in this Bay is centuried old, and it is one of the
few areas famous for successful cultivation and fast growth of oysters
and mussels. Although there is considerable research on the plankton
and shellfish populations, the fish assemblage of Mali Ston Bay is
scarcely known (1). The present study provides preliminary data on
the fish assemblage in the special reservate in Mali Ston Bay, south-
ern Adriatic.
Matherial and methods
Mali Ston Bay is located between the coast and the peninsula of
Pelješac. The waters of the Bay are affected by freshwater discharged
by the Neretva river, underground springs and occasional abundant
rainfall. The greatest part of Mali Ston Bay was proclaimed as a spe-
cial reservation at 2002. Sampling was conducted from May till
August 2003, in several sites. The sampling sites were mostly on
muddy, or sandy-muddy bottoms with rocky boulders and parts over-
grown with Zoostera sp. To depths of 2 m. Fish samples were collect-
ed with beach seine, 25 m long and 5 m high at the central part with
central bag. The mesh size was 8 mm at outer wings, and 4 mm at cen-
tral part of the net. Collected material was kept on ice and brought to
the laboratory for identification. Species were identified according to
(2) and (3). The community structure was specified by species rich-
ness (D), diversity (H) and eveness (J)(4-6).
Results
A total of 4038 fish specimens werecollected, belonging to 14 fam-
ilies and 28 species. The most abundant were members of family
Atherinidae with 88,18% of the catch. Atherina boyeri(81,87%) was
the most numerous, while A. hepsetus(6,31%), Gobius genioporus
(2,15%), Mullus barbatus(1,95%) and M. surmuletus(1,11%) com-
prised 11,52% in total. The remainingspecies contributed less than
0,3% of the catch. The greatest number of species (24) and individu-
als (1694) was caught in May, while the smallest number of individu-
als (489) was caught in August. Most species were present as juve-
niles. The overall value of richness (D) was 3,25, ranging from 2,40
in June to 3,09 in May. The values of diversity (H) was from 0,49 in
June to 1,03 in August with an overall value of 0,94. Evenness (J) val-
ues were from 0,04 in May to 0,17 in June, with an overall value of
0,11.
Discussion
The taxonomic composition of fishes reported in Mali Ston Bay dif-
fers from other protected areas in the Mediterranean (7-9). The differ-
ence may stem from different geographical and geomorphological
features of the Bay. Mali Ston Bay is semi-closed, with relatively lit-
tle water exchange and the mostly mud bottom. The low abundance of
some species, for example Diplodus spp. (except D. annularis) could
be attributed to the paucity of microhabitats suitable for the settlement
of these species. The absence of juvenile stages of Dicentrarchus
labraxand Sparus aurata, typical brackish-water species, possibbly
means that this reservate would not act as an spawning and nursery
center for these species, but somwhere outside of its border, possible
in nearby Neretva river estuary. Atherina boyerimade a signifficant
contribution to the overall number of individuals of the assemblage as
the frequent species of brackish-water ecosystems (10). Similar
results were obtained for shallow coves in the middle Adriatic (11).
The values of diversity, richness and eveness are slightly lower than
values obtained in other bays and estuaries (12-14). This difference
may stem from the lower number of species related to the number of
individuals. The data collected in this study provides preliminary
knowledge of the fish assemblage of the special reservate in Mali Ston
Bay.
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