Iranian Scientific Fisheries Journal
Year:2000 | Volume:9 | Issue:3|Papers Count:8

Noedays, seaweeds have many uses in food industry, weaving, pharmacy, medicine, biotechnology and so on. Many efforts has been made to regenerate seaweeds in artificial media in order to carry out genetic engineering process since 1970. In this study we have tried to establish a proper method for sterilization and tissue culture of brown seaweed, Sargasopsis zanardinii, in 1/2PES, PES and 2PES media. After sterilization, the explants of the seaweed were cultured in liquid and tissue culture of brown seaweed, Sargasopsis zanardinii, in 1/2PES, PES and 2PES media. After sterilization, the explants of the seaweed were cultured in liquid and solid media. Consequently turgidity in margin of explants, longitudinal cell divission and formation of hairy strands, and micro callous formation were showed by explants which cultured in PES and 2PES solid media. After transporting from liquid to solid media, juglike bodies were formed on the surface of solid PES media and then some brown strands were grown from these bodies that finally were flattened. None of these results was obtained from 1/2PES media.

Sex ratio and length at maturity in the rock oyster, Saccostrea cucullata was studied in the Iranian shores of Oman Sea. Monthly sampling was conducted 10 stations within one year priod (March 1996 to February 1997). Results indicated that sex ratio is 1:1. Among the first matured age groups, nearly 67 percent of the samples were male and 33 percent were female. With increasing size, the percentage of females were increased, indicating a protandric nature. More than 50 percent of the samples were matured when their length exceeded 36 mm. Smallest matured specimen had a length of 22 mm.

This research has been conducted in Tonekabon River in 1996. 190 fish samples were take from diferent age groups of 0+, 1+, 2, 3+, 4+. Results indicated that the most highest and lowest abondant were %63, %5.7 in Dohezar and intersection of Dohezar and Cehezar respectively. Maximum body length and weight were 175mm and 84.5g in Dohezar respectively. Minimum body length and weight were 27mm and 0.39 g in Cehezar, respectively. Highest abundant belonged to 2 years age group with 112.3mm average length. Sex ratio was 1:1.4 (female to male). Condition factor of male and female were almost equal (1.268 and 1.257 respectively). Highest feeding intensity was in spring and the lowest was in autumn. Main preys were Simulium, Plecoptera and Ephemeroptera. Growth was positive alometric. Absolute fecundity ranged between 168-379 with an average of 268 eggs.

Heavy metals are the major components in the composition of aquatic environment and living animals, but when the range of these metals change, severe increase or decrease, it can be harmful. In this study, the amount of six heavy metals was measured by cation exchange resin (chelex-100) in 1994-1995. The annual average of the heavy metals was: Fe (113.82), Cd (3.25), Pb (26.34), Ni (17.96), Cu (21.95) and Zn (83.9) µg/lit. In Compare with standard value, it shows that, amount of Cu and Pb in all season and Cd, Zn, Ni in spring and summer are in critical range. There is a significant correlation between concentration of heavy metals and physico-chemical factors such as temperature, pH and salinity.

Members of family Pseudocumidae, order Cumacea are among benthic crustacea that constitute a key part of food chain in the Caspian Sea. Study on identification and distribution of these creatures were conducted under the broad project of "Hydrology and Hydrobiology of the Caspian Sea". During this study which was conducted up to l00m depth (depth of 10, 20, 50 and l00m), 9 species of 4 genera were identified. The four most aboundant species were: Stenocuma diastyloides, Schizorhynchus eudorelloides, Stenocuma gracilloides and Schizorhynchus bilamellatus. Density and number of species sampled from different depths with 4 sampling periods were compared.

The result from conducted surveys on Shirbot (B. grypus) in Khuozestan water bodies showed that this fish has a wide occurance in almost all water bodies, and in a wide range of temperature and salinity. It is revealed that it can grow up to 20 kg in weight. Due toits tasty flesh, there is a good demand for it, specially for local markets. Diet characteristics and food intakes indicate its omnivorous habit. Data indicate that its presence in Khouzestan plain, seems to be mainly for feeding purpose. Its reproductive activities, occure in the northern parts of the regions characterised with sandy or gravel substrate high water current, low temperature and high oxygen content. This condition is not available in Khouzestan plain.

The possibility of culturing milkfish (Chanos chanos) in concrete tanks was conducted. Fingerlings of milkfish were caught from Shoor River (30km east of Bandar Abbas) with surrounding net (25m long, 2m high) and transported to concrete tanks. Three concrete tanks were used for culturing and 100 milkfish fingerlings were stocked in each of them. They were fed with commercial carp food pellet at a rate of %3-5 of their body weight. Temperature and salinity were measured daily. Growth was measured monthly. Results revealed that the growth of milkfish was stopped during the cold season. Mean body weight was about 130 gr after 11 months. Low temperature and poor food with low protein caused slow growth of the milkfish in concrete tanks.