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Larval development and settlement of the barnacle Amphibalanus amphitrite from the Red Sea : Influence of the nauplii hatching season

Al-Aidaroos A.M., Satheesh S.

Oceanological and Hydrobiological Studies

2014

Vol. 43, No. 2

170--177

Barnacle Amphibalanus amphitrite adults were collected from the Jeddah coast of the Red Sea during different seasons. The nauplii released by adults in autumn, winter, spring and summer were reared under laboratory conditions to know the larval development duration and settlement in relation to the hatching season. The nauplii reared during winter (11 days) and autumn (13 days) took longer to reach the cypris stage compared to nauplii reared in summer (6 days) and spring (7 days). The most successful settlement of larvae was observed in spring and summer and the least successful — in winter. The observations of gonads showed that summer and spring are the active breeding season for A. amphitrite in the Red Sea. The results of this study indicated that the nauplii hatching season plays a significant role in the larval development and settlement of barnacles in the Red Sea.

Seasonal composition and population density of zooplankton in Lake Timsah, Suez Canal, Egypt

El-Sherbiny M.M., Al-Aidaroos A.M., Gab-Alla A

Oceanologia

2011

No. 53 (3)

837-859

Zooplankton composition and abundance were investigated seasonally at ten sites in Lake Timsah and the adjacent, connected western lagoon in relation to the physico-chemical conditions. A total of 42 taxa (including larval stages) were identified, among them 21 species of copepods, 6 rotifers, 5 cladocerans, 1 chaetognath and 1 urochordate. Copepods represented the predominant component (77.7% of the total community), followed by rotifers, molluscs, cladocerans and (9.2, 4.7 and 3.9% respectively), while other groups collectively formed about 4.5% of the total zooplankton population. Summer was the most productive season with an average count of 40 864 individuals m-3. The dominant copepod species were Paracalanus crassirostris and Oithona nana representing 28.3 and 24.3% of the total zooplankton respectively. The total zooplankton count, including copepods, and its dominant species showed significant positive correlations with temperature, pH and total phytoplankton density. However, negative correlations were detected between densities of rotifers, and salinity and dissolved oxygen.