Gadoid species such as cod and haddock are most known for a typical dish the British know and love - fish and chips. However the demand for these species is high across Europe and indeed the world which has led to the collapse in many stocks.These are cold water commercial fish species’ that can be found across the Atlantic Ocean. Identified by their speckled brown colour, three dorsal fins, white lateral line and chin barbell, cod live in demersal waters (the area of the water column close to the seabed).
Cod spawning occurs from February to June, where the pelagic (the mid water column) eggs float for several week slowly moving towards coastal waters developing into larvae. Once they arrive at coastal waters, they metamorphose into juvenile fish and inhabit coastal waters for the first year or two before migrating back into deeper waters. Cod reach maturity between the age of 2-4 years, where the adults aggregate into spawning groups to renew the life cycle.
Cod can grow up to two meters and live up to 25 years. The minimum landing size for cod in the UK is 35 cm, however targeted fishing for cod in the Firth of Clyde is prohibited due to low numbers (Barreto and Bailey, 2013).
Demand for cod has been high since the middle of the 19th century; however following a crash in cod in the 1990s various measures have been put in place to improve their situation. North Sea stocks are thought to be improving now, however the UK’s west coast stocks are still low. There are various theories to explain why cod are not recovering including effects of climate change, being caught as by-catch through targeted fishing for other species, increased competition for food, etc. Studies are being conducted to look at the role of coastal nursery habitats for this species as this may aid the future management of this economically and ecologically important species.
Latin name: Gadus morhua
Max size: 2 metres
Minimum landing size: 35 cm
Photos and article: Sophie Elliot, Glasgow University