Mesopotamian Journal of Marine Science

Reviewing the literature on all the nematodes parasitizing 45 species of freshwater and marine fishes of Basrah province (eight elasmobranchs and 37 teleosts) indicated the presence of 48 nematode taxa. Thirty-five of such nematodes were recorded from marine localities against eight taxa from freshwater localities and two taxa from both marine and freshwater localities. These nematodes belong to two classes, three orders and eight families. All such nematodes belong to the class Secernentea except two taxa which belong to the class Adenophorea. Orders Ascaridida and Spirurida are represented with 22 and 24 taxa, respectively, while order Enoplida has only two taxa. The total number of nematode species recorded for each fish host species fluctuated from a minimum of one nematode species in 17 fish hosts to a maximum of eight nematode taxa in Cynoglossus arel only. Number of fish hosts reported for these nematodes fluctuated from one host in case of 31 taxa to a maximum of 20 hosts in case of Contracaecum sp. 1 larva.

Organochlorine pesticides are a class of toxic compounds characterized by their relative chemical and biological stability. They are ubiquitous in the environments and are soluble in liquids. Consequently Organochlorine pesticides have been placed on “the top of black list” of potential environmental hazards. Studies on Organochlorine residues have been carried out between 1979-1991. The residues were determined in water, sediments and organisms collected from the Marshes, Shatt Al-Arab and the Arabian Gulf system. Most of the data confirmed the present of ∑DDT, Endrin, Dieldrin, Chlordane and Heptachlor. Their concentrations ranged from nd-336, nd-111, 12-195, nd-57 and nd-79 ng/l in dissolved, from 0.1-2560, nd-217, nd-0.97 , nd-171 and nd-679 µg/kg in particulate and from 0.04-220, nd-47, nd-22, nd from nd-24 µg/kg in sediments from 1-189, nd-154, nd-32, nd-58 and nd-6 ppb in fish, from 0.59-784, 166-540, 2-72, 5-3.1 and nd ppb in mussel and from 0.3-6.3, nd-0.4, nd-0.8, nd and nd-0.3 ppb in shrimp respectively. In the last decade only two studies on Organochlorine residues have been done. One of them in the Mesopotamian wetlands of southern Iraq in which residues of p,p´-DDT have been detected in 100% of the examined samples. This indicates its ability to persist under severe drying of previously exposed surface sediments, long period of more than 10 years of previously exposed surface sediments, high temperature, and intensive solar radiation, and the other by using samples of water, sediment, fish and shrimp from Hor Al-Hammar Marshes of Iraq, high concentration of chlordane in both water and sediments were shown. Therefore further work is needed to establish the baseline levels of Organochlorine residue in the Marshes, Shatt Al-Arab and the Arabian Gulf region.

Two experiments were carried out on fingerlings of Tilapia zillii to estimate the effect of direct transfer from the control salinity of 15 psu to the different salinities of 1.5, 7.5, 15 and 30 psu during the periods of 6, 24, 48 and 96 hrs for short term effect experiments, and after 56 days for long term effect experiment in the salinities of 1.5, 7.5, 15 and 30 psu. Some physiological parameters (P.C.V.; osmolality; water content; Na+, K+ and Cl-, ions; glucose; total protein) were tested in the two experiments. Results of PCV showed a direct proportion with salinity increase, the time (96 hrs) was enough to reach the stable state of PCV. Fishes reach a new stable range of PCV in the salinities of 1.5, 7.5 and 15 psu after 56 days from transfer. Fishes seem hyperosmotic in the salinities of 1.5 and 7.5 psu and hyposmotic in the salinities of 15 and 30 psu. Plasma osmolality of the blood was significantly greater at 30 psu than the control salinity (15 psu), while it was significantly lower in the salinities of 1.5 and 7.5 psu at the time 96 hrs. Plasma osmolality decreased to values close to those of the three salinities 1.5, 7.5 and 15 psu at the time 56 days, indicating a strong osmoregulatory capacity of T. zillii fish. Water content in the muscles of T. zillii had inverse relationship with salinity increase in short term effect experiment. It was decreased significantly (P ≤ 0.05) at the time 56 days from other times in the short term effect experiment at salinities 1.5, 7.5 and 15 psu. Sodium and chloride ions concentrations had a direct proportion with salinity increase in the short term effect experiment. After 56 days from transfer, sodium and chloride ions concentrations reached a stable state and had close values at the three salinities (1.5, 7.5 and 15 psu), Potassium concentration values had a direct proportion with salinity increase and the values decreased with time at all salinities. However, the potassium concentration had a lower value in contrast to sodium and chloride ions. Glucose concentrations in the plasma of T. zillii had a direct proportion with salinity increase after 96 hrs transfer to different salinities (1.5, 7.5, 15 and 30 psu). The glucose of plasma decreased significantly (P ≤ 0.05) at all salinities (1.5, 7.5 and 15 psu) at the time 56 days compared to its levels at times of short term effect experiment. Protein concentration in the plasma decreased significantly (P ≤ 0.05) in the three salinities (1.5, 7.5 and 30 psu) compared with the control salinity (15 psu) at the time 96 hrs of short term effect experiment. After 56 days from transfer, plasma protein values in the three salinities (1.5, 7.5 and 15 psu) had a significant increase from other times in the short term effect experiment at all salinities. The results indicated that the salinity increase caused an increase in PCV, osmotic pressure, plasma ions, glucose, total protein; of T. zillii plasma and decrease in water content of muscles and fish seemed hyperosmotic in the salinities of 1.5, 7.5 psu and hyposmotic in the salinities of 15, 30 psu, also the time of 96 hrs was not enough for fish to reach the stable osmotic pressure at all salinities.

The present study is concerned with the new records of oligochaete species to the Iraqi fauna. The oligochaete specimens were collected from shallow water of six sites on the bank of Shatt Al-Arab river, southern Iraq, during the period from March to August 2011. These oligochaetes were isolated from the surface layer of sediment and submerged plants. The species are Dero cooperi Stephenson, 1932, Dero sawayai Marcus, 1943, Pristinella idrensis (Sperber, 1948), and Pristinella notopora (Cernosvitov, 1937), they were recorded for the first time from Iraq. Measurements and the most important diagnostic features of these species were presented.

Abstract - This study was conducted during the period from November 2009 to March 2010 when the river of Shatt Al-Arab was subjected to abnormal rising in water salinity. The diversity of rotifers was studied in three different stations included two branches of Shatt Al-Arab River: Station 1 (Al-Asafia), Station 2 (Abu Al-Khaseeb-Jecor) and Station 3 (Shatt Al-Basrah canal). The highest values of water salinity (8.6, 16.7 and 22.5‰) were found during November 2009 in St. 1, St. 2 and St. 3 respectively and the lowest values (1.5, 1.9 and 2.8‰) were recorded in March 2010 in the three stations respectively. About 26 species of rotifers were diagnosed belongs to 16 genera, about 25 species recorded in St. 1 whereas, 13 and 12 species were recorded in St. 2 and St. 3 respectively. Jaccard's index showed presence of similarity of rotifers species between St. 2 and St. 3 compared to St. 1.

About 110 specimens of the goldfish Carassius auratus auratus (Linneaus, 1758) were obtained from the Department of Fisheries and Marine Resources Laboratory College of Agriculture and the Marine Sciences Center, University of Basrah. Morphometric and merestics characteristics were measured, total and standard length ranged between 90-150 mm and between 70-110 mm, respectively. Number of scales in the lateral line ranged from 25 to 27. Number of dorsal branched rays ranged from 14 to 15, gill rakers from 42 to 44. Total vertebrae fin count was 25-27. There were five rays with the branchuiostegal rays.