Reproduction Of Eastern Baltic Cod ( Gadus Morhua Callarias L.) And Formation Of Annual Growth Zones On The Otoliths In 90s ...
No abstracts are to be cited without prior reference to the author.We have analysed research trawl data and commercial trawl and gillnet data of 1993-1998 to identify the changes in maturation of cod, spawning time, dynamic of cod weight during the year and formation of annual growth zones on the co...
| Main Authors: | , |
|---|---|
| Format: | Conference Object |
| Language: | unknown |
| Published: |
ASC 1999
2024
|
| Subjects: | |
| Online Access: | https://dx.doi.org/10.17895/ices.pub.25637637.v1 https://ices-library.figshare.com/articles/conference_contribution/Reproduction_Of_Eastern_Baltic_Cod_Gadus_Morhua_Callarias_L_And_Formation_Of_Annual_Growth_Zones_On_The_Otoliths_In_90s/25637637/1 |
| Summary: | No abstracts are to be cited without prior reference to the author.We have analysed research trawl data and commercial trawl and gillnet data of 1993-1998 to identify the changes in maturation of cod, spawning time, dynamic of cod weight during the year and formation of annual growth zones on the cod otoliths in comparison with long-term data. In 1993-1998 due to slow cod maturation and late spawning fishes with different stages of gonad maturity (II-VI, by VI stages scale) were observed the whole year round in Eastern Baltic. In III and IV quarters of 1995-1996 share of post-spawning (spent) cod in SD 26 and 28 in commercial gillnets and trawl catches was 30-50%, in 1997-1998 - only 20%. The prolongation of time of cod maturation and spawning caused the changes in dynamics of cod weight during the year. The high share of post-spawning (spent) cod in the second half of the year determines the decrease of mean weight-at-age in III-IV quarters practically in all age groups older than 4. In the last years time ... |
|---|