Fox, P.J. (1978) Preliminary observations on different reproduction strategies in the bullhead (Cottus gobio L.) in northern and southern England. J. Fish. Biol., pp. 5-11
| Species | Development state | Trait | Primary Data | Secondary Data |
| Cottus gobio | Egg | Oocyte diameter | Means range from 1.79 to 1.94 | 1.79 mm |
| Cottus gobio | Spawning conditions | Spawning period duration | 1st spanwing observed 15/2-75 and the 4th at 30/5/75 [In the high altitude headwaters of the River Tees, bullheads exhibit a short breeding season during late Paril and first week of May] | 38.5 weeks |
| Cottus gobio | Spawning conditions | Spawning temperature | 7.5-13.5 | 10.5 °C |
| Cottus gobio | Spawning conditions | Spawning release | Apperead to be multiple spawners [...] laid four batches [Other area: Although it is possible that a female might lay parts of her batch separately, the distribution of egg sizes and the very short spawning season both suggest that females only ripen one egg batch per season | Multiple |
| Cottus gobio | Spawning conditions | Parity | In the Bere stream all fish ripen and lay eggs at the end of their first year of life. Thereafter, most of them die and only a small percentage survive to breed in their second year. In the trout beck systme, fish do not ripen eggs until their second or third years of life but the maximum recorded life expectancy appears to be nine years | Semelparous |