Whale sharks, Rhincodon typus, are known to aggregate to feed in a small number of locations in tropical and subtropical waters. Here we document a newly discovered major aggregation site for whale sharks within the Al Shaheen oil field, 90 km off the coast of Qatar in the Arabian Gulf. Whale sharks were observed between April and September, with peak numbers observed between May and August. Density estimates of up to 100 sharks within an area of 1 km2 were recorded. Sharks ranged between four and eight metres’ estimated total length (mean 6.92±1.53 m). Most animals observed were actively feeding on surface zooplankton, consisting primarily of mackerel tuna, Euthynnus affinis, eggs.

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Phytoplankton and zooplankton community structures and abundance were studied in three inland seas around Qatar, two along the eastern coast and one along the northwestern coast. Despite some irregularities, the direct relationship between phytoplankton and zooplankton in both seasons indicates that despite of the oligotrophic nature of the inland seas and consequently the low diversity of species, the zooplankton community density is dependent, with different magnitudes, on the density of the phytoplankton community. Multiple regression analysis indicated that at the time where permissible pollution limits were not exceeded, salinity is the main factor controlling zooplankton distribution in the inland seas, followed by phytoplankton.

Zooplankton samples were collected from the Messaieed Marine Area that is subject to industrial and sewage discharge, thermal pollution, as well as oil loading and unloading activities. Copepods formed 74% of the zooplankton community followed by bivalves (7.6%) and Gastropod veligers (5.5%), Ostracods (4.7%) and Cladocera (3.4%). Industrial discharge not only impacted the total number of zooplankton but also species diversity. Diversity indices were higher for inner coastal waters. Pollution levels more than reduction in food source impacted the distribution of main zooplankton groups. The pollution stress changed the structure of zooplankton community rather than impacting the total population. Copepods showed resistance to oil pollution but were reduced in numbers at areas affected by oxygen demanding wastes. Polychaete larvae and Chaetognatha withstand elevated temperature, ammonia and pH levels.

T he distribution of the tintinnid assemblages was studied in samples collected from 2 areas subjected to primary treated sewage flow and agricultural/industrial mixed discharge along the coastal water of Alexandria during summer 1999 and winter 2000. During the entire investigation, the protozoopiankton were numerically dominated by tintinnids with densities ranging between 26 and 9464 Ind./m. Distinct differences that appeared in the patterns of occurrence and numbers of the tintinnids in those locations, were attributed to different physical and chemical conditions. Tintinnid assemblages were represented by 19 species, the most dominant of which were: Tintinnopsis beroidea, Favella ehrenbergii, Eutintinnus macilentus and Tintinnopsis campanula. Two freshwater tintinnids appeared at the near-shore locations of El-Mex Bay during high flow when salinity reached 9 psu.