Showing 2 results for M. R. Ahmadi
O. Farhadian, M. R. Ahmadi,
Volume 7, Issue 3 (fall 2003)
Abstract
Oval fertilization and survival rates at incubation stage form the most important issues of concern in rainbow trout hatcheries in Iran. Hatchery managers tend to use the best method in fertilizing the ova in order to obtain the highest survival rates. A survey of common fertilization methods may help to determine the best one. In this study, the ova from two groups of 3-5 year-old and younger than 3 years broodstocks were fertilized employing dry and semi-dry methods in normal water and dry and semi-dry methods in fertilization solution. The experiment was carried out in a completely randomized design as a 422 factorial arrangement and with two replicates.
The analysis of final results indicates that the highest survival rates of eggs and larvae were obtained in semi-dry fertilization. These rates significantly increased when fertilization solution was used (P<0.05). Moreover, the survival rates of eggs and larvae of 3-5 year-old broodstocks were higher than those of younger than 3 years. On the other hand, type and methods of fertilization showed no significant differences with degree-day (sum of heat) at developmental stage but the age of broodstocks made significant differences with degree-day from fertilization to the first hatching stage (P<0.05).
A. Ghane, M. R. Ahmadi, A. Esmaili, A. Mirzajani,
Volume 10, Issue 1 (spring 2006)
Abstract
Present study investigates macrobenthic invertebrates and their community structure in Chafrood river to classify and assess the study sites regarding the environmental anthropogenic factors. Along a 9 km distance, 8 study sites were selected, and macrobenthic were monthly sampled using a surber sampler (1600cm2, 250 μ mesh net) with 3 replicate at each station. Collected samples organisms were fixed with 4% formalin and laboratory process including sorting, identification and enumeration of the animals were preceded. During the study 73 benthic taxa were identified which were dominated with aquatic insects larvae especially orders Diptera and Ephemeroptera. The maximum and minimum total abundance was 2335 ind.m-2 in station #2 and 1639 ind.m-2 in station #4 respectively. Benthic animals' frequency data were summarized to community structure metrics including total richness, EPT richness and ratio of EPT frequency to Chironomidae family. A Shannon- Winner diversity index and Hilsenhoff family level biotic index was also determined for each studied station. Result of cluster analysis for stations, based on the community structure metrics and diversity index, was in accordance with the station classification using biotic index and both classify the affected stations at the same group.
