Objective:To investigate the possibility of Aphanius dispar(A.dispar) acting as intermediate host for Clinostomum complanalum(C.complanalum),from Mehran River,Hormuzgan Province of Iran.Methods:During a biological stu...Objective:To investigate the possibility of Aphanius dispar(A.dispar) acting as intermediate host for Clinostomum complanalum(C.complanalum),from Mehran River,Hormuzgan Province of Iran.Methods:During a biological study of A.dispar in Mehran River,Hormuzgan Province,South of Iran,a total of 97 fish specimens were collected in 24 January 2006.Results: 4 specimens(4.12%) including 1 male and 3 female were found infected with C.complanalum metacercaria.These metacercaria were coiled in the epiderm on the body surface of infected fishes.The infection is known as yellow spot disease.The parasite abundance,intensity and prevalence were 0.03%,1.25%and 4.12%,respectively.The infection was higher in females than males.Conclusions:To the best of our knowledge,this is the first report on occurrence of C. complanatum metacercaria in A.dispar in Iran.展开更多
Fishing activities can alter the structure of marine food webs by the selective removal of some species. The changes in the marine food webs of the Hormuzgan waters of the Persian Gulf, Iran were assessed, based on es...Fishing activities can alter the structure of marine food webs by the selective removal of some species. The changes in the marine food webs of the Hormuzgan waters of the Persian Gulf, Iran were assessed, based on estimates of the mean trophic index （MTI） and Fishing in Balance index （FIB）, and on landing profile of the exploited marine community （49 species） during the period, 2002-2011. The total landings （Yt） （R=0.88, P〈0.001） increased gradually while the Y~ of carnivores has slightly declined, and the Yt of herbivores, detritivores and omnivores has increased. Consequently, the MTI significantly decreased （R=-0.69, P〈0.05） at a rate of 0.1 l during this decade. The MTI showed a decreasing trend, which indicates exploitation of marine resources. The FiB index also showed a downward trend and negative values from 2002 to 2009, which may be associated with unbalanced structure in the fisheries, but an upward trend from 2009 to 20ll. The time variation of the landing profile showed two periods with significant differences in their species composition （R=0.88; P=0.005）, and based on analysis of similarity, species have been identified as discriminator species, namely Thunnus albacores and Benthosema pterotum. Results indicate that changes in MTI reflected changes in the Hormuzgan landing structure. The examination of the MTI, FBI, and landing profile （LP） temporal pattern suggests that the status of fishery resources in Hormuzgan inshore waters is overexploited, and provides evidence of the probability that a fishing down process is occurring in this area, and that this trend may continue in the long-tenn. Therefore, environmental fisheries management and conservation programs should be prioritized for these valuable resources.展开更多
文摘Objective:To investigate the possibility of Aphanius dispar(A.dispar) acting as intermediate host for Clinostomum complanalum(C.complanalum),from Mehran River,Hormuzgan Province of Iran.Methods:During a biological study of A.dispar in Mehran River,Hormuzgan Province,South of Iran,a total of 97 fish specimens were collected in 24 January 2006.Results: 4 specimens(4.12%) including 1 male and 3 female were found infected with C.complanalum metacercaria.These metacercaria were coiled in the epiderm on the body surface of infected fishes.The infection is known as yellow spot disease.The parasite abundance,intensity and prevalence were 0.03%,1.25%and 4.12%,respectively.The infection was higher in females than males.Conclusions:To the best of our knowledge,this is the first report on occurrence of C. complanatum metacercaria in A.dispar in Iran.
文摘Fishing activities can alter the structure of marine food webs by the selective removal of some species. The changes in the marine food webs of the Hormuzgan waters of the Persian Gulf, Iran were assessed, based on estimates of the mean trophic index （MTI） and Fishing in Balance index （FIB）, and on landing profile of the exploited marine community （49 species） during the period, 2002-2011. The total landings （Yt） （R=0.88, P〈0.001） increased gradually while the Y~ of carnivores has slightly declined, and the Yt of herbivores, detritivores and omnivores has increased. Consequently, the MTI significantly decreased （R=-0.69, P〈0.05） at a rate of 0.1 l during this decade. The MTI showed a decreasing trend, which indicates exploitation of marine resources. The FiB index also showed a downward trend and negative values from 2002 to 2009, which may be associated with unbalanced structure in the fisheries, but an upward trend from 2009 to 20ll. The time variation of the landing profile showed two periods with significant differences in their species composition （R=0.88; P=0.005）, and based on analysis of similarity, species have been identified as discriminator species, namely Thunnus albacores and Benthosema pterotum. Results indicate that changes in MTI reflected changes in the Hormuzgan landing structure. The examination of the MTI, FBI, and landing profile （LP） temporal pattern suggests that the status of fishery resources in Hormuzgan inshore waters is overexploited, and provides evidence of the probability that a fishing down process is occurring in this area, and that this trend may continue in the long-tenn. Therefore, environmental fisheries management and conservation programs should be prioritized for these valuable resources.
