Decline in aquatic resource STOCKs, occurs for various reasons. Although regulations and measures have proven useful, they have failed to inhibit effectively the STOCK reduction trends. Iranian Fisheries Organization has carried out a great deal of investments and efforts concerning the ENHANCEMENT of the Caspian Sea resource STOCKs through the restrictive regulations, and reproduction and release of various species such as bony fish and sturgeon. Nevertheless, reports of low catch of fish by fishermen and illegal fishing of even released fry have made serious concerns. Consequently, the existing approaches and practices have been questioned. However, resource management is facing a lack of proper understanding of society’s behaviors and attitudes towards the resource conservation and management. It is hard to study behavioral changes, but measuring of attitudes toward the natural resources conservation or ENHANCEMENT, as well as the factors influencing the interest and commitment towards it, seems to be a prerequisite of any plan or program in that regard. The present study measures the fishermen’s attitude by means of Fishbein- Ajzen’s model as important and vital theory of behavior–attitude explanation. Variables such as evaluation of outcome, expectation of outcome or belief, satisfaction of and contribution in STOCK ENHANCEMENT, as well as influenced factors including; personal characteristics, experience, amount of catch, and awareness were examined. In this descriptive analytical research, 180 samples out of the whole 5645 fishermen of the bony fish, in seven coastal towns of the Guilan province, were interviewed through a questionnaire. The study showed a significant positive attitude toward STOCK ENHANCEMENT with 95% confidence. They included fishermen who were literate, more informed, with higher catches, and also who were content with their occupation. However, there was no significant relation between the fishermen's attitude and other factors such as age, experience, and opinions about the restrictive measures.

The used Caspian roach broodSTOCKs for semi-natural propagations are collected from the Gorgan river estuary during February-March every year and transported to the fisheries center of the STOCK ENHANCEMENT and conservation of genetic STOCKs of Caspian bony fishes. Sampling of Caspian roach broodkstcoks for this study perforemed for 5 successiv years duing 2014 to 2018. Total length and weight of the broodSTOCKs ranged from 21 to 32. 5 cm and from 45. 60 to 423. 50 g, respectively. The largest mean value of lengths and weights were observed in February-March 2014, and the smallest in February-March 2018. Age of broodSTOCKs ranged between 3+ and 9+. Abundance of ages and sexes were different between years. Feamles had positive allometry in all years, while that of males ranged 2. 65 and 3. 05 indicating mainly negative allometric pattern. Different instanteneus growth rates were observed during five years, indicating presence of strong and/or weak ages and/or cohorts in the studied populations. Condition factor of the females were larger than that of males in all periods. The results showed that L-infinity of males ranged from 26. 49 to 38. 53 cm, and that of females from 32. 45 to 41. 97 cm, k-coefficient ranged between 0. 12 and 0. 24 (year-1) for males and between 0. 11 to 0. 21 (year-1) for females, and t0 of males ranged from-0. 21 to-0. 34 (year), and that of females from-0. 39 to-0. 99 (year).

This study was conducted to provide procedures for increasing the productivity and profitability of sturgeon culture in Iran. We designed a questionnaire covering economic and ecologic aspects of the activity and distributed it to an expert team comprised economists, statisticians and aquaculturist experts. The team completed the questionnaires to determine the costs of production of a single sturgeon fingerling in Iran, considering all sturgeon centers. Also, documents available in different sections of Iranian Fisheries, specially, accounting, budgeting and STOCK ENHANCEMENT offices were resorted to. Cost of labour comprised 55% of expenditures whereas costs of feeding and fertilizer were found to be 14%. The maintenance cost was assessed as 7% and fertilized eggs cost was 6%. Results showed that on average, the production cost of a single sturgeon fingerling in Iran in the year 2000 was 992 Rls. Among all of the sturgeon breeding centers in Iran, Shahid Rajaee Aquaculture center had the lowest cost of production with 477 Rls., while Shahid Beheshty center had the highest cost amounting to 1224 Rls. The cost of labour has a large share in total expenditures, somewhat caused by the center not being active for six months each year. Tasking the labour force with other activities might reduce the total costs in such hatcheries.

The survey of the fish assemblage in the planned place to establish artificial reefs in the western and eastern bays of Jask was carried out in the winter and spring of 2024. Sampling was done by Gillnet and Trap methods in 4 stations located in the western bay and eastern bay of Jask at a depth of 10 to 30 meters. 68 aquatic species (60 fishes, 5 crabs, 2 oysters, and 1 shrimp) were sampled and recorded. Of these, Nemipterus japonicus (32.6 %) was the most abundant, Saurida tumbil (12.6 %), Anodontostoma chacunda (12.5 %), Ilisha megaloptera (9.8 %), Scomberoides tol (6.4 %), Sphyraena putnamae (4.1 %), Lactarius lactarius (2.6 %), Muraenesox bagio (2 %), Pomadasys kaakan (1.9 %), Otolithes ruber (1.6 %) located in the next rank. The average catch per unit of effort of gillnet was 45±10.2 kg/piece×hour and for Trap 7.3±4.2 kg/trap×day. In this research, it was found that the population of species related to artificial reefs, such as Epinephelus coioides , Lutjanus johnii , and Lethrinus nebulosus were relatively low, and mainly below the maturity size, it seems that the STOCKs of this group of fish need to be enhanced. Therefore, it is recommended to consider the target species in the design of the structure and arrangement of the artificial reefs, on the other hand, the shelter and protective aspects of the artificial reefs for the reef-dependent juvenile also be considered.

Iran contributes to the STOCK ENHANCEMENT of several economically valuable fish species, including the Caspian salmon, S. trutta caspius, by producing and releasing millions of fingerlings into the sea. This work was conducted to determine the production costs of the Caspian salmon fingerlings in the years 2002 and 2003. For this purpose, a questionnaire was prepared and filled in by an expert team using data available in the Kelardasht Caspian Salmon Hatchery and other related departments. Among various expenditures, on average, cost of labor (52%) and cost of feed (16%) had the greatest share. Results showed the average cost of production and release of a single fingerling in Iran was IRRls 6,685, (US$ 0.84) over the 2002-2003. The cost sensitivity of hatcheries production of the Caspian salmon shows that labor cost is the most sensitive, and a 50% increase in the cost of this item increases the total coast by more than 25% followed by feed cost.

Contribution of the production factors, production costs during the years 2000-2004, and means for increasing the productivity and profitability of sturgeon hatcheries in Iran were investigated by compiling and analyzing the available information, including the documents available in ENHANCEMENT offices. We designed a questionnaire covering economic and ecological aspects of the activity and distributed it to an aquaculture related expert team. Different sections of the Iranian Fisheries Organization, specially, accounting, budgeting and STOCK. The results showed the cost of labour and salary comprised 38-56% of expenditures whereas costs of feeding and fertilizer were found to be 4-14%. The maintenance cost was assessed as 4-8%, fertilized eggs cost was 6-35% and depreciation cost was 10-12% of total expenditures. The production cost of a single sturgeon fingerling in Iran was 937-2028 Rls over the 2000-2004. The cost of labour and salary had a large share in total expenditures, somewhat caused by the centers not being active for six months each year. Engaging the labour force with other activities such as cultivation of indigenous and exotic surgeon brooders might be expected to reduce the total costs. With increase in price of caviar in recent years, the price of fertilized eggs has also increased to 35% of total expenditures. It seems cultured sturgeon brooders might fill the gap left by wild brooders inaccessibility in coming years of wild sturgeon.

Over the 2001-03, to determine the costs of production and to calculate the rate of return of a single kutum fingerling releasing in the Caspian Sea, a questionnaire was prepared. An expert team completed the questionnaire, while reffering all kutum centers. Cost of labour and salary, with the greatest share was averaged 43% of operation cost (38% of total costs) and the costs of feed and fertiliser was averaged 17% of operation cost (16% of total costs). Among various expenditures, the cost of labour and salary from 52% of operation costs in 2001 declined to 36% in 2003. Other important expenditures were maintenance and harvesting, handling and releasing were averaged 15% and 9% of operating cost respectively. Results shaw, an average cost of production of a single kutum fingerling in Iran, was Rls. 70, changing from Rls. 37 in 2001 to Rls. 123 in 2003; The cost of labour had a great share in total expenditures, it could be justify by unactivity of centers during a few months off season, which could be reduced by adopting extra activities in such hatcheries, including brood STOCKs farming or production of other species. Over the 2004-2005, with the average of 8.3% rate of fingerling return and the average wieght of 815 grammes and 3.7 fish ages, the number of 19/257/494 kutum fish with the total of 13/000 tonnes, of kutum fish might be harvested. The value of whole sale price of these catches with the price index of the year 2004, is important and might be estimated Rls. 505 billion, Rls.

The purpose of the present study was to determine the dietary organisms in the earthen ponds and the preferences of the fish in the consumption of them. Sampling for 6 weeks was carried out at 6 times in two 4 hectare ponds with 3 sample points in each pond. In order to evaluate zooplankton and benthos from the contents of the stomach, 180 juveniles were sampled. The Results demonstrated that. The highest abundance of food organisms in ponds was Copepoda and naupli with 49. 58 % and the highest amount of them in the stomach contents of of juvenile sturgeon was in the case of Cladocera with 61. 19% and Chironomidae with 25. 27%. Ivlev's index (E) to Cladosera, Ostracoda and Chironomidae were positive. On the other hand, the value of E index for Copepoda was negative. The results of present study showed that, juveniles' sturgeon have a high tendency to feed from Cladosera, Ostracoda and Chironomidae. So that, Cladosera and Chironomidae are among the main food and Ostracoda is considered as an occasional food. When Cladosera, Ostracoda and Chironomidae biomass decreased in the ponds, sturgeon feed from Copepoda.

Contribution change of factor costs analysis may help managers in decision making and in adjusting to changes. Over the last two decades, production and ENHANCEMENT of kutum fingerlings have increased in Iran, reaching to more than 229 million fingerlings by 2005, but declined to 187 million from 2005 to 2008. Over the years 2002-2006, a study of fingerling production costs for kutum fish was carried out. For this purpose, a questionnaire was prepared and filled out by an expert team using data available in kutum hatcheries for fingerling production and other related departments in Iranian Fisheries Organization. Among various expenditures, the contribution cost of labor with the greatest share averaged almost 40% of total costs, followed by feed and fertilizer which averaged more than 15%. Results show, in average, the production cost of a single kutum fingerling was 100 IR Rials (US$ 0.01), which varies from almost 37 IR Rials in 2001 to 130 IR Rials (US$ 0.014) in 2004 and 157 IR Rials (US$ 0.017) in 2005. Yearly growth of a single fingerling was averaged more than 50% from 2001-2005. The results clearly indicated that over the years 2001-2005 the contribution cost of labor and "feed and fertilizer" declined, but it increased for "water and energy" and Miscellaneous. Overall, the costs sensitivity analysis of hatcheries production of kutum fingerling shows labor is the most sensitive, and a 50% decrease of this item, decreases the total cost by almost 20%.