Discrimination between Icelandic cod ( Gadus morhua L.) populations from adjacent spawning areas based on otolith growth and shape

• Published in: Fisheries research Vol. 80; no. 2; pp. 182 - 189
• Main Authors: Petursdottir, Groa, Begg, Gavin A., Marteinsdottir, Gudrun
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-09-2006; Elsevier
• Subjects: Agnatha. Pisces; Animal, plant and microbial ecology; Applied ecology; Atlantic cod ( Gadus morhua L.); Biological and medical sciences; Exploitation and management of natural biological resources (hunting, fishing and exploited populations survey, etc.); Fundamental and applied biological sciences. Psychology; Gadus morhua; Marine; Otolith growth; Otolith morphology; Spawning groups; Stock structure; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; ANE, Atlantic, Iceland; Spawning groups; Otolith morphology; Atlantic cod ( Gadus morhua L.); Stock structure; Otolith growth; Growth; Spawning; Marine environment; Vertebrata; Fishery; Discrimination; Pisces; Morphology; Otolith; Stock; Gadus morhua; Atlantic cod (Gadus morhua L.)
• ISSN: 0165-7836; 1872-6763
• DOI: 10.1016/j.fishres.2006.05.002

Studies on Atlantic cod (
Gadus morhua L.) have demonstrated extensive variation in life history characteristics among populations exposed to different environmental conditions. In Iceland, cod sampled from adjacent spawning areas, within the main spawning area at the southwest coast, exhibit variation in vital life history characteristics. In this study, we investigated the stock structure of Icelandic cod on the main spawning grounds to discriminate between these adjacent spawning groups by using otolith growth and shape. Otolith growth was based on annual increment width estimated for the major age groups (6–7 year olds) of the spawning stock. Otolith shape was determined using Fourier analysis and compared among cod sampled from the different spawning areas with stepwise canonical discriminant analysis (CDA). We found significant differences in growth and otolith shape between adjacent spawning groups of cod where those sampled close to the coast differed from those that were sampled further out on the bank and continental shelf. Our results suggest that these cod may belong to different populations and the large and fast growing cod spawning in the coastal area may need special protection given their significance to the overall productivity of the stock.