30 research outputs found

    Species diversity and distribution pattern of marine mammals of the Persian Gulf and Gulf of Oman - Iranian Waters

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    A total of 98 marine mammal records from Iranian coastal waters of the Persian Gulf and Gulf of Oman were compiled of which 66 are previously unpublished new records. Seventy-nine were from the Persian Gulf and 16 from the Gulf of Oman coast. The largest numbers of records were from Qeshm Island and Bushehr Provinces. Records of finless porpoise (Neophocaena phocaenoides), Indo-Pacific humpback dolphin (Sousa chinensis) and Indo-Pacific bottlenose dolphin (Tursiops aduncus) were by far the most numerous probably reflecting their inshore distribution and local abundance. Other species recorded are common dolphin (Delphinus capensis tropicalis), rough-toothed dolphin (Steno bredanensis), Risso’s dolphin (Grampus griseus), false killer whale (Pseudorca crassidens), and dugong (Dugong dugon). Evidence of 22 Mysticetes were obtained eight of which were tentatively identified as Bryde’s whales (Balaenoptera edeni), three as fin whales (Balaenoptera physalus) and three as humpback whales (Megaptera novaeangliae). The largest threat to marine mammals in Iran is likely to be incidental capture in fishing gear. Six by-caught finless porpoises were recorded, and this species may be particularly vulnerable to incidental mortality in gillnets. Recommended marine mammal research, conservation and management small projects in Iran are described

    Allometric growth pattern and morphological changes of green terror Andinoacara rivulatus (Günther, 1860) (Cichlidae) during early development: Comparison of geometric morphometric and traditional methods

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    Allometric growth pattern and body shape changes of the Green terror (Andinoacara rivulatus) (Cichlidae) were studied using landmark-based geometric morphometric (GM) and traditional methods, from hatching up to 1266 Hours Post Hatching (HPH) under culture conditions. The left side of specimens were photographed using digital camera and morphometric characters, including total length, head length, tail length, trunk length, eye diameter, snout length and body depth were measured using ImageJ software. In GM method, ten landmark-points were digitized on 2D pictures. Allometric growth patterns were calculated as a power function of total length and described by the growth coefficient to reveal important steps in the species’ early life history. The scores of relative warp analysis (RW) were used as descriptors for the variation in shape. The growth patterns obtained by both traditional morphometric (TM) and GM methods showed similar patterns, but GM showed effective results to interpret the morphological changes and revealing larval stages based on the body shape change. The results also showed higher growth rate of head and tail regions up to yolk sac absorption following by isometric patterns, after begin of exogenous feeding. Based on the findings, the early development of this species can be divided into five stages based on its morphology, including newly hatching larvae (up to 48 HPH), younger larvae (156 HPH), older larvae (426 HPH), younger juvenile (666 HPH) and juveniles. The results confirmed this fact that morphological development and growth patterns during early life stages in A. rivulatus closely match its immediate required function

    The effect of monsoon on fish larva assemblage changes in Gowatr Bay, North Oman Sea

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    The study and research of abundance and diversity variation of fish larva (Ichthyoplankton stages) was done in Gowatr Bay during autumn 2006 - summer 2007. Five stations were selected for sampling, and Bongo-Net with 300µ mesh size was towing from bottom to surface. During of survey, totally 531 larvae belong to 11 families were collected and identified. The mean abundance estimated 12.17 larvae per 10 m^2, in which three fish larva family including: Gobiidae, Clupeidae and Engraulidae were dominant (86% of relative abundance). The result showed that there was significant differences between pre and post-monsoon fish larvae abundances (p.05). In pre-monsoon 4 families were identified of which Clupeidae introduced as indicator group, whereas in post-monsoon 10 families were identified and Gobiidae was indicator family, accompany with increase of diversity. PCA result was shown, temperature as the main factor affected on fish larvae assemblage was found with a significant decrease of 11.9 °C after monsoon phenomenon

    Short communication: First report of cyclopoid copepods (Oithonidae) from north-eastern Arabian Sea, Karachi, Pakistan

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    Among marine communities, the importance of small species has been neglected and major attention has been paid to the larger representatives. Small copepods are now assigned as a significant component within marine food webs. Their ecological habitat comprises estuarine, pelagic and coastal environments. Oithona plays a vital role as a food source for other copepods, Chaetognaths, fish larvae and planktivorous fishes. ... Therefore, the present study was conducted to determine the species composition of the genus Oithona previously not known from the coastal waters of Pakistan

    Isolation and screening of antibacterial and enzyme producing marine actinobacteria to approach probiotics against some pathogenic vibrios in shrimp Litopenaeus vannamei

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    The application of new probiotics is a good strategy in the biological control of infectious diseases in aquaculture. Approximately 100 marine actinobacteria isolates were obtained from 10 sediment samples of shrimp farms. Heat treatment of sediment samples resulted in a selective reduction of the non actinobacterial heterotrophic microflora. Starch nitrate agar medium exhibited more efficacy than glycerol arginine agar medium for isolation. Twenty seven percent of actinobacterial isolates showed antagonistic activities against pathogenic Vibrio spp. All the antagonistic isolates showed the typical morphology of genus Streptomyces. Exoenzymatic activity screening showed that 44%, 26%, 37% of antagonistic isolates represented amylase, lipase and protease activities, respectively. MNM-1400 strain exhibited highest antagonistic and exoenzymatic activity. The pathogenicity experiment revealed that MNM-1400 strain did not cause disease in Litopenaeus vannamei larvae. Extraction of produced antibacterial compounds by MNM-1400 strain showed that the active constituent didn’t have non polar property. Morphological, physiological and biochemical identification confirmed that MNM-1400 strain belonged to the genus Streptomyces. Phylogenetic analysis by 16S rRNA gene sequencing showed a high similarity between MNM-1400 strain and Streptomyces californicus (similarity: 99%). These results suggest that the MNM-1400 strain can be considered as a potential probiotic in aquaculture

    Fish larval daily assemblage variations in coastal waters of the Chabahar Bay

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    The survey of fish larvae assemblage variation was done in 2013 seasonally at the coastal areas of Southeastern side of Chabahar Bay. Sampling was done in 3 stations at day and night periods by a Bongo-Net with 300µ of mesh size. 29 families were identified. Clupeidae, Gobiidae and Blenniidae were dominant with more than 50% relative abundance. The PCA result was shown there were two separated groups among day and night fish larval assemblages. Blenniidae ،Scombridae and Clupeidae in day times, Clupeidae ،Gobiidae and Sparidae in night times were more dominant among different families. Station 1 had more fish larvae abundance in autumn in nights and days (54.77 and 79.67 larvae per 10 meter). The average of Shannon index was (0.54 ±0.88 and 0.63± 0.97) in days and nights respectively.Significant increase of larval abundance at station 3 in nights could be due to reduced vessel traffic

    Community composition and diversity of zooplankton in the northwest Persian Gulf

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    Survey on zooplankton composition was studied during June 2015 to March 2016, by selecting six stations along the coastal waters of Bushehr (the Northwest Persian Gulf). Twenty four zooplankton taxa were identified, and the different zooplankton groups represented twenty-one families. Copepoda was recorded with the most abundance (53.30 %) followed by Malacostraca (32.87 %), which in turn was followed by Sagittoidea (7.44 %) and Appendicularia (6.39%). A major peak of 189.34 N/m3 was observed in February-2016 with 53.25% contribution from Copepoda. Among Copepoda, Labidocera sp. was the major contributor to this peak. Appendicularia was the comparatively less represented group, being chiefly represented by Oikopleura dioica. Labidocera sp., Oithona plumifera which were common in most of the stations. This common distribution were observed for Malacostraca, namely Lucifer hanseni (mysis I), Upogebia sp. (zoea I), Parthenope sp., Ilyoplax frater( zoea VI), for Sagittoidea, namely Sagitta enflata, Sagitta neglecta and for Appendicularia, namely Oikopleura dioica. The mean Shannon's diversity index (H') and evenness were 1.36±0.43 and, 0.68±1.17, respectively. The highest Margalef's index was recorded in station-6 (2.72±1.32) and the lowest in station-2 (1.98±0.89). According to non-significant differences between temporal and spatial zooplankton density and Shannon’s index, from an ecological point of view, it seems the study area is unique and the zooplankton composition is homogenous

    Age, growth and spawning season of Luciobarbus esocinus Heckel, 1843 in Gamasiab River, Iran

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    In the current paper reproductive strategy and growth rates of Luciobarbus esocinus were investigated from 2010 to 2012, in Gamasiab River, Kermanshah, Iran. Samples were collected seasonally by gillnet and electro-fisher device. Sex ratio was evaluated from 162 individuals and the percentage of male and female individuals were 54.76% and 45.24% respectively. Age structure was distributed between I and V and most frequency numbers for males and females belonged to II and IV age group, respectively. Length-weight relationship was computed as W=8E-05TL^2.6546 for all individuals. Mean total length and weight was 333.82±13.10 mm and 297.67±4.85 g for males, and 371.5±21.17 mm and 307.85±7.64 g for females. The von-Bertalanffy growth models of L. esocinus were described as Lt =357.14×[1-e^(-0.77×(t-0.090))] for males, Lt =367.02×[1-e^(-0.78×(t–0.094))] for females and Lt =363.57×[1-e^(-0.76×(t –0.087))] for both sexes. Results indicated that growth factors were highly similar in spring, summer and winter. CDA analysis revealed that the total and gonad weight are the main factors in discriminant analysis. The highest GSI values were found in spring for females and winter for males, however, it decreased rapidly after spring in females. Maximum growth rates were observed in early ages (I-II) and depleted with ages. K value and L∞ were determined as 0.77±0.09 Y^-1 and 357.14±10.38 mm for males and 0.78±0.24 Y^-1 and 367.02±24.15 mm for females, respectively. In conclusion this study provided basic information for stock assessment and management of L. esocinus in Gamasiab Reservoir

    Integrated coastal zone management (ICZM) of Iran (Persian Gulf– Oman Sea– Caspian Sea)

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    Coastal areas with about 3700 kilometers of border land and sea, in the north, south and around the islands of the country, one of the potential environmental capacity are economic planning. The coastal area of both the ecological and economic importance. The most important reasons such as marine coastal area of high biodiversity, economic and commercial values, the values of research, mines and aesthetic and recreational values can be cited. Combining development with conservation of natural resources through careful planning based on the principles of sustainable development, one of the objectives of the Coastal Zone Management. Integrated management plan for coastal areas, based on zoning study area into three regions, areas managed by the Department of Environment, Cultural Heritage and Tourism Organization management areas and sensitive habitats within the coastal area have been made. After identify each area as a first step to study the problems of the zone (threat Threats), due to management problems (weaknesses Weaknesses), the facilities available in each area (opportunities Opportunities) and the management strengths (Strengths) each region based on the SWOT model, planning will be discussed. Considering the unique ecological values of coastal ecosystems, the operational objectives of the comprehensive program given the country's Fourth Development Plan, IUCN guidelines and other rules and regulations were extracted

    Environmental and ecological studies in northern Alborz aimed at developing the fisheries resources

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    Caspian Sea with an area of 400 thousand square kilometers is the largest lake in the world. The Caspian Sea about 1200 km from north to south on the longest section and an average width of 320 km. Along the coastline around the Caspian Sea is about 6500 kilometers. Caspian Sea is about 78,000 cubic kilometers of water volume that is 44% of stocks of blue lakes around the world. Caspian Sea basin, which is composed of seven major basins of the main watershed from west to east are: juniper, Talsh- Anzali, large Sefidrood between Haraz Sefid and, Hraz- Gharehsou, Nagorno Sv- Gorgan and Atrak in the basin of Aras no limits to the beach. Aras sub-basin is located in the North West and Iran, the second largest sub-basin of the Caspian Sea. Talysh-Anzali on the Caspian Sea basin West and the seventh largest sub-basin of the Caspian Sea. White basin is located in the South East of the Caspian Sea and the extent of the sub-basin of the Caspian Sea. Haraz located in the south Caspian Sea basin and the ninth largest sub-basin of the Caspian Sea. Gorgan is located in the South East of the Caspian Sea basin and the fourth largest sub-basin of the Caspian Sea. In these areas, about 28 percent of the total fish production in the northern waters of aquatic allocated
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