Ecology of Gadus morhua
Main Ref. Cohen, D.M., T. Inada, T. Iwamoto and N. Scialabba, 1990
Remarks Opportunistic predator that forages mainly at dawn and dusk (Refs. 1371, 46189). Larvae feed mainly on zooplankton while juveniles prey predominantly on benthic crustaceans; adults feed mainly on zoobenthos and fish (Refs. 5743, 9604, 26813) including juvenile cod. Fish prey becomes more common in the diet with increasing body size (Refs. 1371, 89387). Adults may cover large distances during the feeding period (Ref. 89387). Young cod are also preyed upon by different fish species and octopus. Adult cod are prey items of top predators like sharks, rays, whales, dolphins, seals, and sea birds (Refs. 9023, 9581, 26954, 43651, 45735). In the Baltic it grows up to 5 kg weight in 7-8 years; in the North Sea it reaches 8 kg in the same time span . Natural mortality for adults of both stocks is assumed to be around M=0.2, resulting in a mean adult life expectancy and mean duration of the reproductive phase of 5 years (Ref. 88171). Parasites of the species include protozoans (trypanosome), myxosporidians, monogeneid, trematodes, cestodes, nematodes, acanthocephalan, hirudinid and copepods (Ref. 5951).

Aquatic zones / Water bodies

Marine - Neritic Marine - Oceanic Brackishwater Freshwater
Marine zones / Brackish and freshwater bodies
  • supra-littoral zone
  • littoral zone
  • sublittoral zone
  • epipelagic
  • mesopelagic
  • epipelagic
  • abyssopelagic
  • hadopelagic
  • estuaries/lagoons/brackish seas
  • mangroves
  • marshes/swamps
  • rivers/streams
  • lakes/ponds
  • caves
  • exclusively in caves
Highighted items on the list are where Gadus morhua may be found.


Substrate Soft Bottom Hard Bottom: rocky;
Substrate Ref.
Special habitats Beds: sea grass;
Special habitats Ref.


Associations schooling;
Associated with
Association remarks Generally considered a demersal fish although its habitat may become pelagic under certain hydrographic conditions when feeding or spawning. There is some evidence that cod leave the bottom and school pelagically to spawn in preferred temperatures when bottom tempetatures are unsuitable. Gregarious during the day, forming compact schools that swim between 30-80 m above the bottom, and scatter at night (Ref. 1371). Schooling behavior may be adaptive for feeding. Reproductive behavior during spawning involves the circling of a female often by only one male per spawning bout (Ref. 86779).


Feeding type mainly animals (troph. 2.8 and up)
Feeding type Ref. Nordeide, J.T. and J.H. Fosså, 1992
Feeding habit hunting macrofauna (predator)
Feeding habit Ref. Nordeide, J.T. and J.H. Fosså, 1992
Trophic Level(s)
Estimation method Original sample Unfished population Remark
Troph s.e. Troph s.e.
From diet composition 4.09 0.18 4.34 0.72 Troph of adults from 7 studies.
From individual food items 4.29 1.00 Trophic level estimated from a number of food items using a randomized resampling routine.
Ref. dos Santos, J. and S. Falk-Petersen, 1989
(e.g. 346)
(e.g. cnidaria)
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