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  • 1
    Publication Date: 2018-07-14
    Description: In the years 2001 and 2002, two great floods occurred in the Madarsoo River in Golestan National Park, north-east of Iran. To study the effects of these floods, we assessed the age, growth and reproduction of Capoeta capoeta gracilis (Keyserlhng, 1861) in the river from November 2003 to December 2004. Fishes were caught by electroshocker and 1025 specimens were randomly selected from the catch. Growth in length was expressed for both sexes with Von Bertalanffy equation. Growth parameters were estimated as L infinity =249mm, K=0.22 per year and t _ (0) = -0.30 year for males and L infinity =306mm, K=0.21 per year and t _ (0) = -0.38 year for females. The length-weight relationships were described for males as lnW= -4.48 + 3.03 lnTL and as lnW= -4.59+3.0551 lnTL for females which shows a good feeding condition and a positive-isometric growth. Difference of length distribution between males and females is significant and males have lower lengths because this sex matures sooner so its growth is lower than females. Difference of fish length distribution between this study and previous studies on the C. capoeta gracilis of the river is significant and Lenkoran's length shows great decrease in this study as compared to previous studies. Age of the fishes ranged from 1 ^+ to 5 ^+ for males and 2 ^+ to 8 ^+ for females, the dominant age was 2 ^+ and the mean age was calculated as 2.009 ±0.034. We found that C. capoeta gracilis population had become younger in this study, so we concluded that the floods had made great changes in age and length structure of the fish.
    Keywords: Biology
    Repository Name: Aquatic Commons
    Type: Article , PeerReviewed
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  • 2
    Publication Date: 2018-03-06
    Description: During 12 months of sampling, from 17 stations, 327 specimens of Soboor fish Tenualosa ilisha, including 120 females, 113 males and 86 immature were caught. Total length (TL) of the fishes was 120-500mm. Maximum diameters of soboor ova 0.795mm and the ova with diameter more than 0.7 mm released at one spawning round. Temporal and spatial distribution of ova diameter corresponding to GSI changes showed that ova with diameters between 0.64 to 0.795 mm released spontaneously in many rounds along fish migration route during its spawning season. The results indicate that the spawning of soboor begins upon its entering to Bahmanshir and Arvand Rivers on April and continued up to Shushtar and Dezful cities on September where their migration route and season are ended.
    Keywords: Biology ; Fisheries
    Repository Name: Aquatic Commons
    Type: Article , PeerReviewed
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  • 3
    Publication Date: 2018-06-17
    Description: The gobies are non-commercial fishes in the Iranian waters of the Caspian Sea for which population dynamics and stock status are poorly known. In this survey, we tried to define species diversity and catch per unit effort (CPUE) of Gobiidae by using beach seine nets in Salmanshahr, the southern Caspian Sea. From March 2011 to April 2012, 224 specimens representing 4 gobiid species, belonging to genus Ponticola and Neogobius, were caught. The deepwater Goby, Ponticola bathybius (Kessler, 1877), was the most abundant species with 92.8% frequency. The highest catch per unit effort of gobiid fishes was obtained in spring. The species diversity was highest in spring according to Shannon’s index.
    Keywords: Biology ; Fisheries
    Repository Name: Aquatic Commons
    Type: Article , PeerReviewed
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  • 4
    Publication Date: 2018-08-23
    Description: In 1999 Mnemiopsis leidyi was introduced to the Caspian Sea from the Black Sea with ballast waters from the ships. The comprehensive study on probability of controlling Caspian Sea invasive Ctenophora planned after a remarkable of decreeing in Kilka fish catches stocks and fisheris community problems. This study focus on reproduction experiments of Beroe ovata as the best candidate for control of Mnemiopsis population size in the Caspian Sea that was performed in Turkey and Iran during 2002-2003. At 2002, 87 specimens of B. ovata, 10-50 mm transferred to Caspian sea ecology research center from Marmareh sea where acclimated with Caspian sea water gradually. At 2003, experiments were performed near to Black sea (at Sinop) with freshly collected Beroe ovata, 40-65 mm size in three salinity level treatment, the Black sea water 18 , Mixed water 15 and Caspian water 12 . 130 individuals of Beroe ovata were brought from Sinop (Turkey) to Iran during 2003. A number of Beroe specimens were sent to Guilan province for reproduction studies and another part were sent to Mazandaran province for both reproduction and mesocosem studies. For control we had 1 Beroe, length 30 mm in the Black Sea water that was alive during of study in Iran. The Jars were examined each day for ova and larvae and they were collected and put into glass container of Caspian water for hatching and developing survey, some of them were left without any handling for larvae developing. Also in another experiment the eggs collected from jars were placed in the same three treatments for studying of growth and survival. The results were unsuccessful on propagation experiments at 2002 since the spawning and hatching rates were very low (20 ova) and, none of the larvae developed into adults in Caspian Sea water. The spawning was more in Marmareh sea water with 138 ova where only 7 larvae was hatched. Results showed that Beroe specimens is able to survive and reproduce in Caspian water but was not as well as Black Sea also the Beroe larvae growth rate is low in the Caspian Sea water. Maximum fecundity of Beroe individual was 2212 and 235 ovae in Caspian Sea water in site Sinop and Iran respectively. Results showed 34-100% eggs in Caspian Sea water were destroyed and did not develop. In Iran we obtained only one larvae with 5 mm length, other larvae were at different stages of development but most of them were 1.2 2 mm. The results of mesocosm survey showed most of ova and larvae have been obtained from the tanks where individuals B. ovata were with Mnemiopsis. Fecundity of Beroe in the control with Black Sea water were between 17 to 1879 with average of 828 ± 112 ova. The poor results of B. ovata reproduction obtained in this survey in Caspian Sea may be due to transportation and acclimation stress and low salinity of Caspian Sea water.
    Keywords: Ecology ; Fisheries
    Repository Name: Aquatic Commons
    Type: Monograph or Serial Issue , NonPeerReviewed
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  • 5
    Publication Date: 2018-03-07
    Description: In the present study, some ecological factors were studied for Amphipoda at different depths. The Shannon, Margalef, and Hill indices were used to determine the species diversity, richness and evenness, respectively. In addition, the association and niche overlap values were estimated. Indices of species richness and diversity were highest at 50 and 100m depths, respectively. The ordination of depths shows that the highest dissimilarity was at 20m depth and the lowest dissimilarity at 100 meter. Results of interspecific association and specific overlap of species show that only a few species could have similar ecological requirements. Results show that Paraniphargoides derzhavini with Niphargoides grimmi and Stenogammarus compersus with Amathilina cristata had low associations. Corophium spinulosum with Corophium nobile and Stenogammarus compersus with Paraniphargoides derzhavini, however, had high associations.
    Keywords: Biology ; Ecology ; Fisheries
    Repository Name: Aquatic Commons
    Type: Article , PeerReviewed
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  • 6
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    In:  Beaufortia (0067-4745) vol.48 (1998) nr.9 p.173
    Publication Date: 2015-06-03
    Description: Records of 185 amphipod samples taken in Iran, both in the brackish Caspian Sea and in fresh waters belonging to the Caspian drainage system and the Central Basin. Twenty-nine species are represented (25 Gammaridae, 1 Pontoporeiidae, 1 Gammaracanthidae, 2 Corophiidae), of which 1 species of Obesogammarus, and 6 species of Gammarus (all from inland waters), 1 species of the new genus Scytaelina, and 1 species of Derzhavinella (both from the brackish Caspian Sea) are new to science, Obesogammarus turcarum, Gammarus imberbus, and G. syriacus are new to Iranian continental waters, whereas Gammarus aequicauda and Pontogammarus borceae are new to the Caspian Sea.
    Keywords: Iran ; Amphipoda ; new species ; Obesogammarus ; Gammarus ; Derzhavinella ; Scytaelina n. gen
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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