Mann, 1980



Citation


No detailed citation.

Associated characteristics


Species Development state Trait Primary Data Secondary Data
Gobio gobio Female Maximum GSI value Huge variations between females, from 4 to 22, most between 12-18% in May 15.0 percent
Gobio gobio Male Onset of spermatogenesis Developed gradually through the winter ['February', 'March', 'January']
Gobio gobio Male Maximum GSI value Huge variations between individuals: mostly 1-3% in May 2.0 percent
Gobio gobio Female Age at sexual maturity Nearly all fish were mature at the end of their third year, and approximatively 64% of all males after two years 2.0 years
Gobio gobio Male Main spermatogenesis activity Increased rapidly in size just prior to spawning in late May and early June ['May', 'June']
Gobio gobio Female Onset of oogenesis Increase in October ['October']
Gobio gobio Female Intensifying oogenesis activity April ['April']
Gobio gobio Female Absolute fecundity Mean number of eggs per fish in successive age groups: 4812 [Age 2], 9787 [Age 3], 15950 {Age 4], 20823 [Age 5] in Frome, 5044 [Age 3], 4472 [Age 4], and 6781 [Age 5] in Thames, 500 [Age 2], 1500 [Age 3], 3000 [Age 4] and 4-5000 [Age 6] in Nivelle, 1721 [Age 3], 2053 [Age 4], 2886 [Age 5], 3585 [Age 6], 5610 [Age 7] in Dunajec 2502.0 thousand eggs
Gobio gobio Female Length at sexual maturity Female were mature at 9.29 in Stour 9.29 cm
Gobio gobio Male Length at sexual maturity Mean size of mature males 10.46 cm in Frome and 9.66 cm in Stour 10.46 cm
Gobio gobio Female Age at sexual maturity Nearly all fish were mature at the end of their third year, and approximatively 89% from females and 74% Stour females spawnerd after two years 3.0 year
Gobio gobio Spawning conditions Spawning release Most females lay two or more batches of eggs each season Mutliple
Gobio gobio Spawning conditions Parity Both sex had low survival rates ad their reproductive life spans were rarely more than three years No category