The present study investigates the effects of different routes of inulin administration as prebiotic on gut microbiota and survival rate of Indian white shrimp post-larvae. Four hundred and fifty Indian white shrimp post-larvae (PL1) were stocked in nine tanks. The tanks were assigned into three treatments: feeding with inulin-treated (110 mg L-1) Artemia nauplii (I-T), feeding with inulin-enriched (110 mg L-1) Artemia nauplii (I-E) and control which repeated triplicates. Feeding trial was performed until PL11 stage and then gut microbiota was studied using culture based method. Also, survival rate was calculated at the end of feeding trial. Our results showed that feeding on inulin enriched or treated Artemia nauplii had no significant effect on total viable culturable autochthonous bacteria and Vibrio spp. levels of the gut microbiota (p > 0.05). However, a remarkable increase of lactic acid bacteria levels (LAB) was observed in I-E treatment (p < 0.05). Administration of inulin enriched Artemia nauplii significantly elevated survival rates of Indian white shrimp post-larvae (p < 0.05). These results encourage administration of prebiotic-enriched Artemia nauplii in post larval stage of Indian white shrimp but determination the mode of action of prebiotic on various aspects of shrimp larviculture merit further research.

a b s t r a c tIn the present study, some biological traits of Caridina fossarum reproduction are studied in the GhompAtashkedeh spring (Fasa, Shiraz, Iran), for the first time. This Iranian endemic freshwater species was studied from April 2007 to March 2008. Minimum sexable size (MSS) and absolute or relative size at the onset of maturity (SOM and RSOM) in terms of carapace length (CL) was found to be 2.4 mm, 4.3 mm and 55%, respectively. Sex ratio showed variations on a monthly basis. Sex reversal is a possible scenario for C. fossarum because the size-specific sex ratio revealed a reverse pattern. Based on the proportions of ovigerous females, the main breeding season was determined to be from April to August, demonstrating a peak during early spring. There is a period of extended recruitment at water temperatures above 20 • C. The size at which 50% of females are mature was estimated at CL = 5.03 mm from the proportion of ovigerous females during the breeding season. The pleopodal egg number varied from 3 to 75 eggs per female with a mean value 34.39 ± 14.27. The results showed that although there is a significant relationship between carapace length CL and pleopodal egg number, it is not the most important factor affecting potential fecundity in C. fossarum due to the low values of slope (= 1.51) and determination coefficient (= 0.052).

This study aimed to investigate some key aspects of the reproductive strategy ofOcypode rotundataMiers, 1882 from southwest beaches of Qeshm Island, Persian Gulf, Iran, by providing information regarding its sex ratio, sexual maturity, spawning period and fecundity. Samples were taken monthly, from February 2015 to January 2016. Size at the onset of morphometric maturity was estimated at 38.57 mm carapace width. The overall sex ratio (males/females) was observed as 1.13 : 1.00. On monthly based analyses, the sex ratio showed no significant differences, although a significant deviation was observed toward males in the larger size classes. According to the gonadosomatic index (GSI), gonad maturity and occurrence of ovigerous females, the main breeding season occurs from March to October, with a remarkable peak in June. Fecundity ranged from 24 152 to 10 5287 eggs per individual, with a mean value of 52 389 ± 25 660. The ratio between fecundity and carapace width varied from 632 to 2044 eggs/mm (mean: 1198 ± 472 eggs/mm) and fecundity relative to total mass varied from 771 to 1965 eggs/g (mean: 1336.66 ± 425.43 eggs/g). The reproductive output ranged from 1.04 to 3.78 (mean: 2.35 ± 0.90). The shape of the egg was spherical and it included 6 stages of growth, ranging from fully filled with yolk to fully occupied by the embryo. We concluded that reproduction inO. rotundatais seasonal, and that spawning occurs in an appropriate period to ensure maximum survival of the offspring. The fecundity ofO. rotundatais higher than that of other species of Brachyura, with GSI variations being related to temperature. Overall, the results of this study provide relevant information for the reproduction in general and the breeding seasons ofO. rotundata, whicht can be useful for conservation and management policies aimed at preserving the biodiversity of ghost crabs along the Persian Gulf’s sandy shores.

Summary Length–weight relationships (LWR) of fishes are necessary for various purposes such as stock/ecological assessment, monitoring and management (Froese, 2006). In this study we report length–weight relationships for five species of stingrays found in the Persian Gulf, Iran. Only one LWR was previously reported in the scientific literature for Rhinoptera javanica (Raje, 2000).