Spawning behavior in Atlantic cod: analysis by use of data storage tags

2014 ◽  
Vol 506 ◽  
pp. 279-290 ◽  
Author(s):  
TB Grabowski ◽  
V Thorsteinsson ◽  
G Marteinsdóttir
Keyword(s):  
Data Storage ◽  
Atlantic Cod ◽  
Spawning Behavior ◽  
Use Of Data ◽  
Data Storage Tags

Evidence of spawning skippers in Atlantic cod from data storage tags

2014 ◽  
Vol 156 ◽  
pp. 23-25 ◽  
Author(s):  
Ingibjörg G. Jónsdóttir ◽  
Vilhjalmur Thorsteinsson ◽  
Ólafur K. Pálsson ◽  
Gunnar G. Tómasson ◽  
Christoph Pampoulie
Keyword(s):  
Data Storage ◽  
Atlantic Cod ◽  
Data Storage Tags

scholarly journals Evidence for alternative migratory behaviours in the northern Gulf of St Lawrence population of Atlantic cod (Gadus morhua L.)

2013 ◽  
Vol 70 (4) ◽  
pp. 793-804 ◽  
Author(s):  
Arnault Le Bris ◽  
Alain Fréchet ◽  
Peter S. Galbraith ◽  
Joseph S. Wroblewski
Keyword(s):  
Data Storage ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Fork Length ◽  
Daily Maximum ◽  
Migration Routes ◽  
Data Storage Tags ◽  
Spawning Behaviour ◽  
Using Data ◽  
Migration Propensity

Abstract Le Bris, A., Fréchet, A., Galbraith, P. S., and Wroblewski, J. S. 2013. Evidence for alternative migratory behaviours in the northern Gulf of St Lawrence population of Atlantic cod (Gadus morhua L.). – ICES Journal of Marine Science, 70: 793–804. Inter-individual variation in migration propensity affects population dynamics and connectivity. The diversity of migratory behaviours of Atlantic cod (fork length >40 cm) in the northern Gulf of St Lawrence was studied using data-storage tags that record depth and temperature. Movement patterns of Atlantic cod equipped with data-storage tags were reconstructed using a geolocation model based on daily maximum depth and bottom temperature. Reconstructed migration routes revealed the previously undocumented coexistence of resident and migratory individuals in the population. Migratory cod overwintered in relatively deep (300–500 m) and warm (5°C) waters, while residents displayed a prolonged period of immobility in shallow (<100 m) and near-freezing (–1.5°C) coastal waters of western Newfoundland. In the spring, migratory cod displayed extensive diel vertical migration suggestive of spawning behaviour. The presence of alternative migratory behaviours should be considered in the spatiotemporal management of the collapsed population.

scholarly journals Otolith shape differences between ecotypes of Icelandic cod (Gadus morhua) with known migratory behaviour inferred from data storage tags

2017 ◽  
Vol 74 (12) ◽  
pp. 2122-2130 ◽  
Author(s):  
Hlynur Bardarson ◽  
Bruce. J. McAdam ◽  
Vilhjalmur Thorsteinsson ◽  
Einar Hjorleifsson ◽  
Gudrun Marteinsdottir
Keyword(s):  
Data Storage ◽  
Gadus Morhua ◽  
Fourier Transforms ◽  
Function Analysis ◽  
Variable Temperature ◽  
Otolith Shape ◽  
Use Of Data ◽  
Data Storage Tags ◽  
Migratory Strategies ◽  
Definition Of

Otolith shape can be used to identify ecotypes of the Icelandic cod (Gadus morhua) stock. The use of data storage tags has increased our knowledge of the stock structure of Icelandic cod. The profiles of tagged cod reveal different migratory strategies. This has led to the definition of two ecotypes within the cod stock. Frontal ecotypes reside in deep waters during feeding season and express a highly variable temperature profile associated with thermal fronts, while coastal ecotypes stay in shallow waters all year round. In this study, the data storage tag profiles were analysed with cluster analysis, which revealed the existence of an intermediate behaviour that expresses a variable depth profile and feeding migration that is both shorter in time and not as deep. The main objective was to develop a morphological key based on otoliths to distinguish the ecotypes. The shape of the otoliths was extracted with shape measurements and fast Fourier transforms. A discriminant function analysis indicated a difference in morphology between the ecotypes, resulting in successful classification.

Evidence from data storage tags for the presence of lunar and semi-lunar behavioral cycles in spawning Atlantic cod

2015 ◽  
Vol 98 (7) ◽  
pp. 1767-1776 ◽  
Author(s):  
Timothy B. Grabowski ◽  
Bruce J. McAdam ◽  
Vilhjálmur Thorsteinsson ◽  
Gudrún Marteinsdóttir
Keyword(s):  
Data Storage ◽  
Atlantic Cod ◽  
Data Storage Tags

Thermoregulatory behaviour in cod: Is the thermal preference in free-ranging adult Atlantic cod affected by food abundance?

2019 ◽  
Vol 76 (9) ◽  
pp. 1515-1527 ◽  
Author(s):  
Björn Björnsson
Keyword(s):  
Growth Rate ◽  
Data Storage ◽  
Gadus Morhua ◽  
Cold Water ◽  
Atlantic Cod ◽  
Vertical Mixing ◽  
Metabolic Energy ◽  
Fat Reserves ◽  
Free Ranging ◽  
Thermoregulatory Behaviour

This study supports the hypothesis that well-fed cod (Gadus morhua) seek higher temperatures to increase growth rate, and poorly fed cod select lower temperatures to save metabolic energy. Depth and temperature of free-ranging adult cod (44–79 cm) were studied with data storage tags as part of a ranching project in an Icelandic fjord. Forage fish were regularly provided at four feeding stations where cod formed distinct “herds” (herd cod) that did not mingle much with the rest of the unconditioned cod in the fjord (wild cod). Several parameters (stomach fullness, liver index (fat reserves), condition factor, and growth rate) indicated that food intake was much greater in herd cod than in wild cod. In August, when the thermocline was well established, the herd cod remained in shallow (15–35 m) and warm water (8–10 °C), whereas the wild cod stayed in deep (80–90 m) and cold water (3–4 °C), but occasionally both groups explored depths and temperatures outside their preferred range. After vertical mixing in autumn when thermoregulation was not possible, the depth difference between the two groups decreased significantly.

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