Temporal and spatial variations in percentage cover of macroalgae on rocky shores in South of Caspian Sea (Astara to Babolsar)

The most important primary producers of rocky shores are macroalgae. The present study investigated the temporal–spatial changes, the percentage of coverage and the influence of abiotic factors on macroalgae on rocky shores of southern Caspian Sea. Ten sampling stations were selected in the natural and artificial rocky shores from Astara to Babolsar. Sampling lasted for one year and took place every 2 months from September 2013 to July 2014 using a 50×50 quadrate sampler. Epibenthic macroalgae consisted of 2 genus, Cladophora and Entromorpha, from green algae and one genus, Laurenica, from red algae. The average water temperature, salinity, pH, dissolved oxygen and water conductivity were 16.48 °C, 9.87ppt, 8.27, 9.89 mg/l and 16.52 m/s, respectively. According to the results, the maximum algal coverage was observed in September (70.50 %) and the minimum coverage was observed in January (21.50 %). Results of one-way ANOVA indicated that the mean of algal coverage in various months of the year were significantly different (P<0.05). One-way ANOSIM ecosystem similarity test indicated that the coverage rates of the stations were homologous and similar. The results also showed that temperature has a significant effect on macroalgae coverage ratio on rocky shores in the southern Caspian Sea

Study of fish meal substitution with earthworm in diet of rainbow trout (Oncorhynchus mykiss)

This experiment was carried out to evaluate the effect of earthworm (Eisenia fetida) in diet for rainbow trout in a complete randomized design with 5 treatments in triplicates using 15 cages in a pound for 8 weeks. Ten fish with average weight 120 g was stocked in each replication. The earthworm (as fed) at the levels of 0, 25, 50, 75 and 100% was replaced with fish meal in rainbow trout diet. Results showed that feed intake decreased significantly (P b0.05). The chemical composition analysis of fish meat showed that there were no significant effects between control and 25% and 50% earthworm in diet for dry matter, crude protein and ash, but fat content significantly decreased as earthworm increased (P < 0.05). This present study showed that the earthworm (Eisenia fetida) can be used in rainbow trout diet up to 50% instead of fish meal