| Autor: |
Fadaee, B., Pourkazemi, M., Tavakoli, M., Joushideh, H., Khoshghalb, M.R.B., Hosseini, M.R., Abdulhay, H. |
| Předmět: |
|
| Zdroj: |
Journal of Applied Ichthyology; Dec2006 Supplement, Vol. 22, p160-165, 6p, 2 Charts |
| Abstrakt: |
To understand the probability of returns of released sturgeons, a total of 266,796 juveniles of sturgeons (Acipenser persicus, Huso huso, Acipenser stellatus) in 3 weight categories of under 3 g, 3-5 g and over 5 g were released. Tagging took place at the Beheshti, Marjani and Rajayee sturgeon hatcheries between 2000 and 2003 using CWT tags. Fish were released into the rivers (SefidRud River, Tejen River and Gorganrud River) entering the Caspian Sea. Additional to CWT (coded wire tags) tagging some 5500 juveniles of Persian sturgeons (A. persicus) weighing between 2 and 5 g were also tagged by cutting their barbels. Trawl, gill net and beach seines were used to test the re-capture rate of tagged sturgeons in shallow waters down to a depths of 10 m along the coastal areas of the Caspian Sea. Trawling was applied in the water of the Gilan Province between 2000 and 2001 and 43 juveniles were caught, however, none carried CWT tags. Gill nets were used in the Gilan Province in 2002 and 2003 and in Mazandaran and Golestan Provinces in 2003. In total 2,084 fish were caught using gill nets. Nine specimens of Persian sturgeon over 5 g, 11 specimens between 3- 5 g and 6 specimens below 3 g as well as 2 specimens of stellate sturgeon over 5 g were recaptured while carrying CWT tags. Beach seine was used to study fish populations in the Gilan Province in 2003. Some 2,978 Persian sturgeons were caught with this gear of which 37 were identified with a cut barbel. Due to variation in sampling time and the various fishing methods used at different stations, the question of the appropriate representativeness of the recovery rate is pertinent and the data gained may not yet provide a full answer to the hypothesis at which size and time the release may be the most effective one. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
