Main Ref. | Cohen, D.M., T. Inada, T. Iwamoto and N. Scialabba, 1990 |
Mode | dioecism |
Fertilization | external |
Mating type | |
Spawning frequency | one clear seasonal peak per year |
Spawning aggregation | Yes. Ref. SCRFA, Science and Conservation of Fish Aggregations, 2018 |
Batch spawner | Yes. Ref. Kjesbu, O.S., H. Kryvi, S. Sundby and P. Solemdal, 1992 |
Reproductive guild |
nonguarders open water/substratum egg scatterers |
Parental Care | none |
Description of life cycle and mating behavior | Spawning occurs in winter and beginning of spring, where big schools are formed. Spawning sites are in offshore waters, at or near the bottom, in 50-200 m depth and 0-12 °C (preferred range 0-6°C) (Refs. 1371, 89387). May form spawning aggregations in the water column when bottom temperatures are unsuitable (Ref. 1371). Different spawning areas may be used in subsequent years (Ref. 89387). Embryo development lasts about 14 days (at 6°C) and larval phase lasts about 3 months(at 8°C). Fecundity ranges from 2.5 million eggs in a 5 kg female to a record of 9 million eggs in a 34 kg female. Reported number of batches spawned in an experiment is 8 - 22 (Ref. 5513). Sex ratio is nearly 50%, with slight predominance of females. Classified as a determinate multiple spawner (Ref. 40290). Older and larger cod had been found to produce larger eggs with neutral buoyancy at lower salinities. This can be crucial to egg and larval survival (Refs. 31930, 38384). Larvae are pelagic up to 2.5 months before settling on the bottom (Ref. 1371). In the Baltic, spawning cumulates in March at depths below 20 m near the bottom. The nursery areas are in the inner coastal zone. Recruitment to the fished stock starts below 2 years and peaks at about 3 years of age (Ref. 5947). |
Search for more references on reproduction | Scirus |