Distribution and growth biology of rock oyster Saccostrea cucullata in the Oman Sea

Distribution and growth biology of rock oyster (Saccostrea cucullata) in the northern shores of Oman sea have been struied. During this one-year study, samples have been taken monthly from ten different stations. quantity of vertical distribution of this species was obseredl in the mid - intertidal zone. After determining the spread pattern, the following subjects were studied: - Growth parameters - Distionction of the "cohorts" - Determination of "spawning Season" - Condition of the "Gonado Somatic Index" - Sex ratio - Length of the species during the first year of maturation. - Identification and determination of percentage of "Biofouler Organisms." Results obtained from the above - mentioned studies show that considering a growth factor (k) of 0.52, the value of "Loo " for this species is equal to 114 (mm).Five to six different age groups were observed among the samples taken. In the areas where this study was conducted, this species grows 24 to 30 (mm) in the first year of its life this growth rate is lower in the higher - aged grpups relative to the lewer - aged groups, so that the longest size classes grow between 4 to 6 (mm) per year. • The maxinum Value of the "Condition Index" is in the pozm area and the minimum value of it belongs to Darak and Tang areas. Along with the increase in the growth of gonads the above mentioned condition index increases gradually simultaneous with the onset of spawning. Also, study of the influence of environmental factors on the maturation process suggests that the most important factors affecting maturation and spawing are temperature and salinity. The study of GSI shows that this species has a coordinated bimodal spawing trend, with its spring peak in june and its autumn peak, being still higher than the spring peak, in september. The recruitment curve confirms the above spawning peaks with its peaks occuring after a delay of one month or maximum two months in comparison to the spawning peaks. The results of calcuation of "Sex Ratio" of this species in each area show that sex ratio is 1:1. Among the first size classes that reach maturity, nearly 67% of the samples are male and the remaining 33% are female. with the increase in the shell size, the percentage of males decreases and the percentage of females increases. , The above facts prove the protandrous nature of this species the diagram showing the sizes of the first samples which reach maturity suggests that more than 50% of the samples mature after their length exceeds 36 (mm). The shortest mature sample was found to have a length of 22(mm). After studying "Biofouler Organism" nine different invertebrate groups were indentified. Barnacles and Tunicates have the highest and lowest percentages respectively. According to zonal observations, Barnacles and polychacta do the greatest damage to this species

Effect of 17- alpha- methyl testosterone on cichlid kaliko (Labeotropheous foellobroni) sex reversal

In this present study, Cichlid Kaliko (Labeotropheous foellobroni) fallowing was exposed to 17-alpha-methyl testosterone at 2 stages of development including prior to maturity (larvae) and after puberty (broodstock). The influence of sex hormone on the larvae was also explored. The first group was the larvae under the four treatments (0, 50,100, 250) mg per kg of food and hormones that broodstock group also included four treatments (0, 100, 250, 400) mg per kg food three replicates were performed in a period of 30 days. Hormone was added to fish food. Results showed that treatments had a significant difference in fish growth, which correlated with increased amounts of 17 alpha-methyl testosterone. In group I, food with 250mg/kg testerone resulted in an increase in growth indices (i.e.s, SGR=1.4, ADG= 6.5) with a mortality rate of 48.3 percent. In group II results showed that treatment of G (400mg testosterone per kg food) produced larvae with maximum growth indices (SGR=0.91, ADG= 3.6) and the least mortality rate of 31 percent; Research revealed that 17 alpha methyl testosterone could have an effect on Calico fish sex changes in both larval and stock stages

Data from: Cytochrome c oxidase subunit 1 barcode data of fish of the Nayband National Park in the Persian Gulf and analysis using meta-data flag several cryptic species

No description availabl

MER 10-0368R1

Figures and tables; include taxonomical data, divergence values and NJ trees of Nayband fish samples as well as a number of comparisons with similar species from other sea