Journal of the Persian Gulf (Marine Science)
Volume:7 Issue: 25, Fall 2016

In this study, effect of different levels of dietary protein (25, 35 and 45 per cent) and water salinity (0-3, 12-15 and 32-35 ppt) on antioxidant enzymes of white leg shrimp (Penaeus vannamei) was studied. 324 P.vannamei (with mean weight±SE: 5.55 ± 0.18 gr) were randomly distributed in twenty seven tanks. Experimental shrimps were fed by formulated diets for 56 days and at the end of the experiment, total antioxidant capacity (T-AOC) and activity of super oxidase dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) of hepatopancreas and muscle tissue were measured. The results showed significant difference in antioxidant enzymes activity of experimental shrimps among different treatments. This study showed that increasing trend on levels of dietary protein (especially 45%) at different water salinity, cause oxidative stress and increase the activity of antioxidant enzymes. Also, changes in water salinity from 32-35 to 12-15 and 0-3 ppt significantly increased (P>0.05) the activity of antioxidant enzymes in the hepatopancreas and muscle tissue of white leg shrimp. In general, level of 35% dietary protein and salinity of 32-35 ppt are appropriate conditions for culturing of juveniles of white leg shrimp.

The distribution of some rare earth elements (La, Ce, Sc, and Y) in the sediment samples, collected form 56 stations in the offshore of the Persian Gulf during the Persian Gulf and Gulf of Oman Oceanographic Cruise (PGGOOS) in 2012, was studied. The elements were determined by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The result revealed that the concentration of Ce (82 µg g-1) was the highest, and La lowest (0.01 µg g-1). The average concentrations of elements were 11.7, 5.6, 5.4 and 3.5 µg g-1 for Ce, Y, La and Sc, respectively. Enrichment factors (EF) indices showed the enrichment for Ce, while the other elements had EF<1. The concentration ratios of La/Sc (1.6) and Ce/La (2.1) indicated redox status of the surface sediments in the studied region of the Persian Gulf

Hermit crabs community in the intertidal zones of Larak Island were investigated through a seasonal sampling at five stations using random quadrate sampling method. Overall, seven species were identified and Clibanarius signatus was the dominant species, which showed high dominance over other species. Using Bray-Curtis cluster analysis for comparing seasonal abundance showed that except spring, other seasons form one cluster. A significant correlation was observed (P<0.05) between Simpson dominance index with temperature, dissolved oxygen and total organic matter. This study showed that the Simpson dominance index was high, primarily because of high dominance of C.signatus in intertidal zones of Larak Island. The high species dominance and low species richness in hermit crabs community in Larak Island could be because of unsuitable living conditions and lack of habitat diversity, such as muddy shores and mangrove forests.

This research aims at identifying and ranking the effective factors in constructing dry ports in Iran. Initially, by reviewing the literature and inputs from professionals, 20 important criteria impacting constructing dry ports were identified,categorized under three groups of infrastructure, hardware and software and data were collected through questionnaire.
Questionnaire’s validity was determined by university professors and professionals and reliability of the questionnaire was evaluated by Cronbach’s Alpha, which showed an acceptable level of 0.789. Collected data were analyzed by appropriate tatistical tests. The results showed that the main dimensions of software, hardware and infrastructure were the most effective factors in constructing dry ports in Iran respectively. Moreover, of the 20 identified criteria, “the availability of the equipment and facilities for loading and unloading”, “providing the customs and clearance services”, “access to the national and international main routes (hinterland)” were the most important criteria and have had the most effects on
constructing dry ports. Criteria such as “access to the empty container for commercial transactions”, “proximity to the production markets and “access to the borders” showed the
least effect on constructing dry ports in Iran.

The present study (i.e. the first study in Iraqi waters) identified the causes of reproduction and excessive growth of the jellyfish, which is known locally as thagolol, of the type (Catostylus Perez) in the region of Shatt Al-Basrah canal, west of Basrah city. The reproduction and excessive growth of jellyfish occurs in many estuaries and coastal areas in the world, which is a recurring global problem in the context of climate change. The conducted study included measurements of dissolved oxygen, electrical conductivity, total dissolved solids, pH, temperature, nitrates, phosphate, quality and quantity of phytoplankton during the dominant of :the northwest winds; the neap tide and during a full tidal periods in October of 2018 and March of 2019. The results showed that there were thrive of jellyfish by huge numbers in Shatt Al-Basrah canal. The physical; chemical and biological causes (i.e., the local causes), were identified, namely: (1) marine salinity, (2) water column temperature stratification in the context of climate change, (3) an excessive increase in the concentrations of nitrate and phosphate, (4) abundance of phytoplankton (i.e., dinoflagellate), including Protoperidium sp. and Alexandrium; and (5) overfishing of fish. Hence, the absence of
any of these factors will lead to the absence of this type of jellyfish.

Seven phytoplankton species (Alexandrium sp., Prorocentrum micans, Cochlodinium (aka Margalefidinium) polykrikoides, Mesodinium rubrum, Akashiwo sanguinea, Gonyaulax
polygramma, Ceratium sp.) were found as the main cause of Harmful algal blooms (HABs) in a three-year record of red tides in Chabahar coastal waters (North of Gulf of Oman). Autumnal blooms of Gonyaulax polygramma and Prorocentrum micans are reported for the first time in the region. The most frequent bloom events were caused by Akashiwo sanguinea (i.e. 4 times) and Mesodinium rubrum (i.e. 3 times). The highest observed density was at Oct 2017 caused by Akashiwo sanguinea (15.3*106/ litre). The recorded temperature range was from 24.4 to 31.5°C and the DO ranged widely from 3.9 to 11.2 mg/liter. In conclusion, HABs occurrences are not associated with the expansion of one particular species but with multiple taxa and there is aد suitable environmental condition for HABs in the autumn and spring in the region.