نشریه آبزیان زینتی
سال سوم شماره 3 (پاییز 1395)

Aim of present study was to use the wood chips (sawdust) as a cheap substrate and source of carbon in the ammonia fixation and its impact on increasing the survival chance of fishes. According to this, fished were divvied into control group (Aquarium without sawdust) and treatment group (Aquarium containing to %10 of total volume) with four replications. 10 mg of ammonia was added to the aquarium and were calculated ammonia levels 24, 48, 72 96 hours after the addition of ammonia. In second stage, in addition to wood chips, aquarium containing the fishes. The mortality was counted in intervals of 24, 48, 72 and 96 hours after the addition of ammonia. Results were significant difference (p

Fish innate and adaptive immune and relevant factors are transferred from mother to offspring. These factors include IgM, lysozyme, lectin, cathelicidin and complement components. Maternal transfer of immunity is dependent on the health and immunity status of spawners and cause the defense in the seeds and larvae. The health status of brood stock fish can also affects breeding performances, spawning quality and production of offspring. Factors such as age, maturity, nutrients (micro and macronutrients), and seasonal changes (e.g photoperiod, temperature, unsuitable and stressful environmental conditions like handling, crowding, and water pollution) may also affect the immunity of brood stocks. Maternal immunity is of high importance for reducing mortalities at larval stage. This study investigates maternal immune components and affecting factors. This topic is very important in ornamental fish because of the sensitivity and importance of survival and resistance of larvae.

Many studies have been done on the effect of probiotics in aquaculture, but in the context of their effects on fish reproductive activities, few studies have been done. In this study, the effect of probiotic Primalac on some reproductive parameters in sword tail fish was examined. Female and male fish were fed 5% of body weight with the concentration of 0.0 (control), 0.4, 0.9 and 1.4 g primalac kg-1 of dry diet (twice a day) for a period of 3 months. At the end of the experiment gonadosomatic index, the number of larvae per female, relative fecundity, survival rate and the percentage of defective larvae were evaluated. Results showed that relative fecundity and gonadosomatic index in treatment 0.4 g was significantly higher than other treatments (P

It is now more than 10 years that scientists start DNA barcoding for species and still fish DNA barcoding is in infancy stage. International Barcode of Life states that ‘‘DNA sequence can be used to identify different species, in the same way, a supermarket scanner can use a familiar black strip of the UPC barcode to identify purchases’’. So, we can identify the fish species quickly with the help of the barcode reader. Reliable recovery of the 5′region of the cytochrome c oxidase I (COI) gene is critical for the ongoing effort to gather DNA barcodes for all fish species. It may help to develop fish DNA barcoding more easily as well as quickly. In other respect Species hybridization and very recently radiated species can represent a problem for barcoding. Supplementary studies show that problems with the accuracy of taxonomic identifications are more important than these tow subjects and DNA barcoding can help to correct misidentification. Finally, barcoding would be useful for regulating marine ornamental fish trade/export/imports there by contributing to the effective management of resources.

Stability, physical form diet pellets are very important during consumption and prevention of early leaching into water. In sustainable aquaculture quality of diet is very important, Because about 60% of the total cost is related to production fish diet, diet quality plays a vital role in aquaculture. Therefore, during the preparation of a high quality diet it is necessary to pay attention to cost, stability, physical form and feed requirements. Feed stability could be increased by using binders. So, binders can improve the pellet strength and reduce the corrosion rate during the processing and transport of feed. On the other hand, pellet leaching in water cause the loss of ingredients and reducing the nutritional value of feed. Moreover, deposition the material in the bottom of the pool and their metabolism will increase the BOD in water. So, pathogens and consequently their secondary effects have good condition to grow. The best binders are those that in addition to increase the feed strength can decrease the expenditure and be available. Different types of binders are included: carboxymethyl cellulose, corn starch, sodium bentonite, aqua cube and so on. The aim of the present project was to study the variety of used binders in aquaculture and introduction of the best of them with the optimum efficiency.

Harpacticoid copepods are a promising alternative food resource for larval and juvenile fishes that require live feeds in mariculture. Harpacticoids, fed alone or as a supplement, have been shown to promote faster growth than rotifers, brine shrimp, or both together. Research suggests that this is most likely related to small body size from first nauplius to adult, which favors ingestion by gape-limited fishes, and the observation that harpacticoids are naturally rich in essential fatty acids needed for marine fish growth. In addition, cultures of harpacticoids have the potential to be productive enough to be of value in mariculture because harpacticoids (a) have high reproductive output and short generation times; (b) are able to withstand variable conditions of temperature, salinity, and waste accumulation; and (c) have flexible food requirements regarding nutritional content and particle shape and size that facilitate the use of formulated feeds, monospecific algae, or both. Characteristics associated with a primarily benthic lifestyle, however, render many harpacticoid species inappropriate for large-scale mariculture applications. Most have been cultured only in the presence of substrates, complicating the harvest of early developmental stages because few harpacticoid nauplii swim. Furthermore very few species encyst or undergo diapause, requiring that high yields from mass cultures be synchronized with the birth or arrival of larval fish.