Mesopotamian Journal of Marine Science

The present study was focused on the infections of some zooplankton groups (copepoda and rotifer) with ecto and endo parasites in Iraqi marine and estuarine brackish water during the period from January to the end of October 2010 by seasonally intervals. Samples were collected from 5 selected stations represent Iraqi marine and brackish waters. Many parasites were recorded on copepods and other zooplankton in the study area, these are: Ellobiopsis chattoni, Ellobiopsis sp., Thalassomyces sp., Blastodinium sp., Zoothamnium sp., Dinoflagellate and peritrich ciliates. These parasites were recorded for the first time in Iraqi marine and brackish waters except for Ellobiopsis chattoni, and the genus Thalassomyces sp. which were recorded in Kuwaiti waters before. The percentage and the intensity of infections were studied; the highest percentage of infections copepods was 35.7% in winter at station 4, while the lowest was 0.73% at stations 2 during autumn. The highest percentage of infections in rotifers was 9.49% at station 1 during autumn, while the lowest percentage was 0.15 % at station 3 during winter. The highest mean intensity of the copepods was 12.03 at station 1 during summer, while the lowest value was 1.05 in the same station during autumn. The highest mean intensity of the copepods and rotifers was 6.3 at station 2 during summer, while the lowest was 0.8 in the same station during autumn. Scanning Electron Microscope (SEM) was used in this study for identification of some ecto parasites of copepods.

In the present study, the functional anatomy, histological features and histochemical localization of two enzymes viz., alkaline phosphatase (ALPase) and adenosine triphosphatase (ATPase) of the olfactory epithelium in Rita kuturnee were described. The structural organization of the olfactory epithelium was studied by using the histological and histochemical techniques. The morpho-anatomical study revealed that the paired olfactory chambers were situated at the dorsal-lateral sides of the snout, which was communicated outside by an anterior and posterior nasal openings. The elongated olfactory rosette lied at the bottom of chamber and supported with 54-56 lamellae on either side of the central narrow raphe. The histological analysis characterized the olfactory epithelium of lamellae which was made up of receptor, flagellated supporting, non-flagellated supporting, labyrinth, mucous and basal cells. Intense alkaline phosphatase and adenosine triphosphatase activity were evidenced in the receptor cells, supporting cells, basal cells and also in blood cells of the central core. Various cells lining the olfactory epithelium were correlated with the functional significance of the fish was concerned.

Reviewing the literature on all the protozoans and myxozoans parasitizing freshwater and marine fishes of Basrah Province, Iraq indicated the presence of 25 protozoans (one sarcodinid, six mastigophorans, one opalinid, four epicomplexans and 13 ciliophorans) as well as ten myxozoans. Some of these parasites infect skin, fins and gills of their hosts while others are internal parasites of fish muscles, body cavity and different body viscera. Apart from one taxon which was recorded from a marine locality, the remaining taxa were recorded from freshwater localities. The total number of protozoan and myxozoan species recorded for each fish host species fluctuated from a minimum of one parasite species in 11 fish hosts to a maximum of 15 parasite species in Silurus triostegus. Number of fish hosts reported for these parasites fluctuated from one host in case of 21 parasite species to a maximum of 19 host species in case of the ciliophoran Trichodina domerguei.

In the present study, different concentration of salinity (4, 6, 8, 12 and 14 ppt) was studied for 21 days during December 2015, and compared with 1.4 ppt to investigate its effects on growth, nutrition and survival percentage rate of Silver carp (Hypophthalmichthys molitrix). The average of water temperature was 18.17 °C±1.3, dissolved oxygen was 7.9±0.60 (mg/l), hydrogen ion (8.13±0.327). The study showed that the mortality percentage for fish exposed to 14 ppt of salinity was 100 % after 24 hours, while the others was exposed to different concentration of salinity (4, 6, 8 and 12 ppt) were 0, 0, 0 and 25 % respectively after 21 days comparing with control (1.4 ppt) was 0 %. Inversely relationship was seen between food intake percentage and various concentration of salinity, the highest percentage of food intake 6.11 % in treatment of control (1.4 ppt) and the lowest 1.99 % in concentration 12 ppt. Statistic analysis was demonstrated that there significant differences (P<0.05) in rate of food intake ratio between treatments 1.4, 4, 6, 8 and 12 ppt.

Flushing time for tidal rivers and estuaries is of great benefits for those involved in taking appropriate decisions in water resources management. Shatt Al-Arab River is the main and only source of fresh water to Basra City, South of Iraq. Unfortunately, this river is facing an environmental deterioration as a result of presence of many pollution sources. The calculated flushing time of the river helps to estimate the expected time needed to renew the river water. Fresh water fraction method was used to calculate flushing time. The results showed that three factors are responsible for affecting the value of flushing time. These factors are upstream coming flow discharge, phenomenon of tide and lastly the location distance from the estuary. The results also showed that the flushing time of the northern part of the river from Maqal port until the confluence with Karun River are much more than that of southern part. Results also showed that the flushing time for the whole parts of the river was 2.4 months.

The larvae of Tenualosa ilisha were surveyed in the present research at four stations in the Shatt Al-Arab River and East Al-Hammar marsh. The study was conducted from April 2013 to March 2014. Water temperature was ranged from 12°C in December to 38 °C in July at all stations. Salinity was changed from 9.35‰ in October to 36 ‰ in August at station A, while salinity changed was from 1.03 ‰ - 3.5 ‰ at stations B, C and D. A total of 185 T. ilisha larvae (5.0-20 mm TL.) were collected. Higher number of T. ilisha larvae was recorded at station C (88), comprised 47.56 % of the total fishes larvae collected, and the lowest number (23) was from station A, comprised 12.43 % of the total fishes larvae collected. T. ilisha larvae were found in the study region during eighth month of the year, from March to October. The highest abundance of larvae at station C in March was 3.28 larvae/10 m², and lowest was 0.14 larvae/10 m² at station D in April. Water temperature showed a significant positive correlations with abundance of T. ilisha larvae at stations A, B, C and D (r = 0.833, o.692, 0.890, 0.616 p < 0.05 respectively). While, the salinity showed negative correlations with abundance of T. ilisha larvae at stations A (r = -0.700, p < 0.05), and a weak negative correlations with stations B, C and D (r = -0.523, -0.455, -0.470 p < 0.05 respectively). The results sh0wed that Shatt Al-Arab river and East Al-Hammar marsh play a vital role in T. ilisha reproduction, may urgent plan need to it protect the spawning and nursery ground for larvae of this species.

Two methods were used for the determination of four toxic elements (mercury, arsenic, cadmium and lead) in the Iraqi marine waters. Water samples were collected from eight stations along the Iraqi marine waters. Three stations were selected from nearby zone of the Fao city in southern of Iraq towards Khor Abdullah, these regions were considered as an important navigation line on one hand between Iraq and Iran and on the other hand between Iraq and Kuwait. The other five stations were extended between Umm Qasr port towards Khor Al-Zubair port while the last station was selected from the nearby zone for confluence zone between Khor Al-Zubair port and Shatt Al-Basra canal. All the samples were collected during low tide at depth of 10 cm from surface water. Mercury and arsenic were analyzed by ICP instrument while lead and cadmium were determined through using Atomic absorption spectroscopy (AAS). The recorded data of the total concentration for all the elements have shown the average of concentration as follows: 0.0060 mg/l, 0.0765 mg/l, 0.0518 mg/l and 0.9229 mg/l for metals mercury, arsenic, cadmium and lead respectively. Moreover, some physico-chemical properties of water were recorded in these stations.