scholarly journals Impacts of regular and random noise on the behaviour, growth and development of larval Atlantic cod ( Gadus morhua )

2015 ◽  
Vol 282 (1817) ◽  
pp. 20151943 ◽  
Author(s):  
Sophie L. Nedelec ◽  
Stephen D. Simpson ◽  
Erica L. Morley ◽  
Brendan Nedelec ◽  
Andrew N. Radford
Keyword(s):  
Growth And Development ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Acoustic Noise ◽  
Random Noise ◽  
Mitigation Measures ◽  
Lower Body ◽  
Body Width ◽  
Sound Levels

Anthropogenic noise impacts behaviour and physiology in many species, but responses could change with repeat exposures. As repeat exposures can vary in regularity, identifying regimes with less impact is important for regulation. We use a 16-day split-brood experiment to compare effects of regular and random acoustic noise (playbacks of recordings of ships), relative to ambient-noise controls, on behaviour, growth and development of larval Atlantic cod ( Gadus morhua ). Short-term noise caused startle responses in newly hatched fish, irrespective of rearing noise. Two days of both regular and random noise regimes reduced growth, while regular noise led to faster yolk sac use. After 16 days, growth in all three sound treatments converged, although fish exposed to regular noise had lower body width–length ratios. Larvae with lower body width–length ratios were easier to catch in a predator-avoidance experiment. Our results demonstrate that the timing of acoustic disturbances can impact survival-related measures during development. Much current work focuses on sound levels, but future studies should consider the role of noise regularity and its importance for noise management and mitigation measures.

The Role of Circulating Catecholamines in the Ventilatory and Hypertensive Responses to Hypoxia in the Atlantic Cod (Gadus morhua)

1991 ◽  
Vol 64 (4) ◽  
pp. 1087-1109 ◽  
Author(s):  
Richard Kinkead ◽  
Regina Fritsche ◽  
Steve F. Perry ◽  
Stefan Nilsson
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod

The role of spawning stock in formation of recruitment of northeast atlantic cod Gadus morhua

2006 ◽  
Vol 46 (1) ◽  
pp. 74-82 ◽  
Author(s):  
V. M. Borisov ◽  
A. A. Elizarov ◽  
V. D. Nesterov
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Northeast Atlantic ◽  
Spawning Stock

The growing degree-day and fish size-at-age: the overlooked metric

2007 ◽  
Vol 64 (2) ◽  
pp. 375-385 ◽  
Author(s):  
Anna B Neuheimer ◽  
Christopher T Taggart
Keyword(s):  
Growth And Development ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Variable Temperature ◽  
Spatial Scales ◽  
Explanatory Power ◽  
Field Studies ◽  
Fish Length ◽  
Degree Day ◽  
Size At Age

Growth rate in ectotherms, including most fish, is a function of temperature. For decades, agriculturalists (270+ years) and entomologists (45+ years) have recognized the thermal integral, known as the growing degree-day (GDD, °C·day), to be a reliable predictor of growth and development. Fish and fisheries researchers have yet to widely acknowledge the power of the GDD in explaining growth and development among fishes. We demonstrate that fish length-at-day (LaD), in most cases prior to maturation, is a strong linear function of the GDD metric that can explain >92% of the variation in LaD among 41 data sets representing nine fish species drawn from marine and freshwater environments, temperate and tropical climes, constant and variable temperature regimes, and laboratory and field studies. The GDD demonstrates explanatory power across large spatial scales, e.g., 93% of the variation in LaD for age-2 to -4 Atlantic cod (Gadus morhua) across their entire range (17 stocks) is explained by one simple GDD function. Moreover, GDD can explain much of the variation in fish egg development time and in aquatic invertebrate (crab) size-at-age. Our analysis extends the well-established and physiologically relevant GDD metric to fish where, relative to conventional time-based methods, it provides greater explanatory power.

Covariation between grey seal (Halichoerus grypus) abundance and natural mortality of cod (Gadus morhua) in the southern Gulf of St. Lawrence

2005 ◽  
Vol 62 (9) ◽  
pp. 1991-2000 ◽  
Author(s):  
G A Chouinard ◽  
D P Swain ◽  
M O Hammill ◽  
G A Poirier
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Population Analysis ◽  
Halichoerus Grypus ◽  
Natural Mortality ◽  
Grey Seal ◽  
Synthetic Populations ◽  
Time Period ◽  
Abundance Indices

More than 10 years after the collapse of Atlantic cod (Gadus morhua) fisheries in Canada, the role of increased seal populations in the decline and lack of recovery of the stocks continues to be discussed. Using removals and abundance indices from synthetic populations, we found that sequential population analysis can uncover trends in natural mortality. We used this approach to examine variation in natural mortality (M) of southern Gulf of St. Lawrence cod. M increased from the late 1970s to the mid-1990s but declined slightly recently. Results were consistent with previous work indicating that M increased in the 1980s. Changes in estimated M for this cod stock matched fluctuations in grey seal (Halichoerus grypus) abundance. The increase in grey seal abundance from the late 1970s to the mid-1990s corresponded with the increase in estimated M of cod over this time period. The correspondence between seal abundance and M of cod supports the hypothesis that seal predation may be a cause of increased M. However, the diet information available suggests that seals consume mainly juvenile cod, whereas our evidence for an increase in M is for larger cod (ages 3 years and older).

The role of seasonally altering photoperiod in regulating physiology in Atlantic cod (Gadus morhua). Part I. Sexual maturation

2007 ◽  
Vol 64 (1) ◽  
pp. 84-97 ◽  
Author(s):  
Andrew Davie ◽  
Mark JR Porter ◽  
Niall R Bromage ◽  
Herve Migaud
Keyword(s):  
Sexual Maturation ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Reproductive Activity ◽  
Continuous Illumination ◽  
Natural Photoperiod ◽  
Artificial Photoperiod ◽  
Commercially Important ◽  
Photoperiod Manipulation

While the Atlantic cod (Gadus morhua) displays clear seasonality in its reproductive cycle, the exact photic signal that entrains this rhythm is yet undefined. This present work developed a model to describe the photic regulation of reproduction in the species in comparison with other commercially important temperate teleosts. This was achieved through the strategic masking of the natural photoperiod cycle during the first 2 years of life with the application of continuous illumination. The results demonstrated that it is the falling autumnal photoperiod signal after the summer solstice, more specifically after October, that is responsible for recruiting individuals to enter the sexual maturation cycle. Furthermore, in all treatments where this signal was masked through the application of continuous illumination, there was no significant reproductive activity and growth was improved by up to 60% at 27 months posthatch. This information is of particular value to the developing cod aquaculture industry in which the management of reproduction using artificial photoperiod manipulation will be of vital economic importance.

The function of sound production by Atlantic cod as inferred from patterns of variation in drumming muscle mass

2004 ◽  
Vol 82 (9) ◽  
pp. 1391-1398 ◽  
Author(s):  
Sherrylynn Rowe ◽  
Jeffrey A Hutchings
Keyword(s):  
Sexual Selection ◽  
Muscle Mass ◽  
Morphological Traits ◽  
Gadus Morhua ◽  
Sound Production ◽  
Atlantic Cod ◽  
Size Condition ◽  
Spawning Behaviour ◽  
Fitness Benefits

We quantified variation in the mass of drumming muscles (the sound-producing musculature) among individual Atlantic cod (Gadus morhua L., 1758) for comparison with other evidence on the role of sexual selection in the evolution of sound production by this species. Based on 913 cod sampled from the Western Scotian Shelf in 2001–2002, we found that males had drumming muscles that were larger than those of females and that increased in mass prior to spawning and declined thereafter. Drumming muscle mass was highly variable, particularly among males, and generally more variable than other morphological traits (somatic mass and body length). This pattern of drumming muscle variation is consistent with the hypothesis that drumming muscles are influenced by sexual selection and suggests that sound production by males during the spawning season has fitness benefits, perhaps through a role in mate competition. Drumming muscle mass of spawning males was also positively associated with body size, condition, and fertilization potential, suggesting that sound production may be an indicator of the size of the signaler and may reveal information about individual quality. In conjunction with previous studies of sound production by Atlantic cod, our study underscores the potential importance of sound production to cod spawning behaviour.

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