ABUNDANCE OF CLADOCERANS IN THE ERDEK BAY (SW MARMARA SEA)
Ozgur Emek Inanmaz *, Cetin Keskin
Canakkale Onsekiz Mart University, Faculty of Fisheries, Canakkale, Turkey -* emek1@turk.net
Istanbul University, Fisheries Faculty, Laleli, Istanbul, Turkey -seahorse@istanbul.edu.tr
Abstract
In this study abundance of Cladocerans were examined in the Erdek Bay (SW Marmara Sea) during the period of July 2000 to May 2001.
Samples were collected from eight stations by horizontal houl using standard plankton net. In the study, totaly six species were found.
Annual average abundance of Cladocera in the Erdek Bay was calculated as 734,89 ind./m
3
and total abundance of zooplankton consisted
of 29.7% of Cladocerans. Cladocera reached maximum abundance in the summer.
Key words: Cladocera, Abundance, Marmara Sea
Rapp. Comm. int. Mer Médit., 37,2004
371
Introduction
Marmara Sea plays an important role as an acclimatization zone, a
biological corridor or a biological barrier on the spreading of marine
fauna and ?ora between the Mediterranean and Black Seas. Regarding
the coastal artisanal fishery, Erdek Bay has a significant importance in
the Marmara Sea. According to the researchers (1, 2) coastal areas of
this bay are suitable breeding and nursery grounds for the larvae and
juvenile fish. Marine zooplankton has a important role in the food
chains of the sea as they transfer energy from the phytoplankton to
higher trophic levels. Marine cladocerans predominate mainly in
coastal ecosystems and contribute significantly to zooplankton
abundance. For that reason we aimed to determine their abundance
and contribution to total zooplankton.
Methods
Samples were collected from eight stations horizontally (Fig. 1)
and monthly intervals with 115
µ
m mesh size standard plankton net
and results were evaluated seasonally (Table 1).
Fig. 1. Study area.
Table 1. Seasonal average abundance (ind/m
3
)of species of Cladocera,
total Copepoda and other zooplankton (Chetognatha, Appendicularia,
Annelida, Bivalve veliger etc.).
Results
Six species of Cladocera have been determined in the Erdek Bay:
Penilia avirostrisDana, 1849
Evadne nordmanniLovén, 1835
Evadne spiniferaMüller, 1868
Evadne tergestinaClaus,1877
Pleopsis polyphemoidesLeuckart, 1859
Podon intermediusLilljeborg,1853
P. avirostrisand E. tergestinawere found dominant in summer
while P. polyphemoidesand E. nordmanniwere found in spring. Other
species of Cladocera were found rarely in all seasons. As it can be
seen from table 1 there is a negative correlation between Cladocera
and Copepoda (r: -0.65, P<0.05).
Discussion
Study results showed that Cladocerans contribute significantly to
zooplankton abundance. Some researchers reported that P. avirostris,
E. tergestina, P. polyphemoidesand E. nordmanniappeared highly
concentrations in stagnant and polluted waters (3,4). For that reason
Erdek Bay should be observed periodically.
It can be seen that there is a competition between Copepoda and
Cladocera (r: -0.65, P<0.05). Similar results reported by Tarkanet al.
(5). We think that interactions between Copepoda and Cladocera
affected seasonal variation of zooplankton.
Acknowledgement.This study supported by Istanbul University
Research Found.
Project No: T-918/06112000.
References
1-Inanmaz, O.E., 2001. Abundance and Distribution of Cladocera
Populations in the Erdek Bay. MSc Thesis. University of Istanbul. Science
Institute. 58 p.
2-Keskin, C., 2002. Composition of Juvenile Fish Populations of Erdek
Bay (Marmara Sea). PhD. Thesis. University of Istanbul. Science Institute.
83 p.
3-Apostolopoulou, M.M., Kiortsis, V. ,1977. Notes écologiques sur les
Cladocères marins de Grèce. Rapp. Comm. int. Mer Médit., 24, 10: 113-
114.
4-Lakkis, S., 1981. Les Cladoceres Des Eaux Libanaises: Observations
Faunistiques et écologiques. Rapp. Comm. int. Mer Médit.,27, 7: 155-157.
Monaco.
5-Tarkan, A.N., Morkoç, E., Sever, T.M., 2000. Izmit Körfezi Baskin
Zooplankton Türleri. S: 468-474. Marmara Denizi 2000 Sempozyumu
Bildiriler Kitabi. Yayin No: 5. ISBN 975-97132-1-7. Istanbul.
