scholarly journals Climate change in fish: effects of respiratory constraints on optimal life history and behaviour

2015 ◽  
Vol 11 (2) ◽  
pp. 20141032 ◽  
Author(s):  
Rebecca E. Holt ◽  
Christian Jørgensen
Keyword(s):  
Metabolic Rate ◽  
Life Histories ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Standard Metabolic Rate ◽  
Aerobic Scope ◽  
Trade Offs ◽  
Different Temperatures ◽  
The Difference ◽  
Common Trade

The difference between maximum metabolic rate and standard metabolic rate is referred to as aerobic scope, and because it constrains performance it is suggested to constitute a key limiting process prescribing how fish may cope with or adapt to climate warming. We use an evolutionary bioenergetics model for Atlantic cod ( Gadus morhua ) to predict optimal life histories and behaviours at different temperatures. The model assumes common trade-offs and predicts that optimal temperatures for growth and fitness lie below that for aerobic scope; aerobic scope is thus a poor predictor of fitness at high temperatures. Initially, warming expands aerobic scope, allowing for faster growth and increased reproduction. Beyond the optimal temperature for fitness, increased metabolic requirements intensify foraging and reduce survival; oxygen budgeting conflicts thus constrain successful completion of the life cycle. The model illustrates how physiological adaptations are part of a suite of traits that have coevolved.

scholarly journals Physiological basis of temperature-dependent biogeography: trade-offs in muscle design and performance in polar ectotherms

2002 ◽  
Vol 205 (15) ◽  
pp. 2217-2230 ◽  
Author(s):  
H. O. Pörtner
Keyword(s):  
Metabolic Rate ◽  
Aerobic Capacity ◽  
Anaerobic Capacity ◽  
Standard Metabolic Rate ◽  
High Energy ◽  
The Arctic ◽  
Aerobic Scope ◽  
Physiological Basis ◽  
Activity Maximum ◽  
Trade Offs

SUMMARYPolar, especially Antarctic, oceans host ectothermic fish and invertebrates characterized by low-to-moderate levels of motor activity; maximum performance is reduced compared with that in warmer habitats. The present review attempts to identify the trade-offs involved in adaptation to cold in the light of progress in the physiology of thermal tolerance. Recent evidence suggests that oxygen limitations and a decrease in aerobic scope are the first indications of tolerance limits at both low and high temperature extremes. The cold-induced reduction in aerobic capacity is compensated for at the cellular level by elevated mitochondrial densities, accompanied by molecular and membrane adjustments for the maintenance of muscle function. Particularly in the muscle of pelagic Antarctic fish, among notothenioids, the mitochondrial volume densities are among the highest known for vertebrates and are associated with cold compensation of aerobic metabolic pathways, a reduction in anaerobic scope, rapid recovery from exhaustive exercise and enhanced lipid stores as well as a preference for lipid catabolism characterized by high energy efficiency at high levels of ambient oxygen supply. Significant anaerobic capacity is still found at the very low end of the activity spectrum, e.g. among benthic eelpout (Zoarcideae).In contrast to the cold-adapted eurytherms of the Arctic, polar (especially Antarctic) stenotherms minimize standard metabolic rate and, as a precondition, the aerobic capacity per milligram of mitochondrial protein,thereby minimizing oxygen demand. Cost reductions are supported by the downregulation of the cost and flexibility of acid—base regulation. At maintained factorial scopes, the reduction in standard metabolic rate will cause net aerobic scope to be lower than in temperate species. Loss of contractile myofilaments and, thereby, force results from space constraints due to excessive mitochondrial proliferation. On a continuum between low and moderately high levels of muscular activity, polar fish have developed characteristics of aerobic metabolism equivalent to those of high-performance swimmers in warmer waters. However, they only reach low performance levels despite taking aerobic design to an extreme.

Accuracy and precision in stock separation of north-east Arctic and Norwegian coastal cod by otoliths - comparing readings, image analyses and a genetic method

2005 ◽  
Vol 56 (5) ◽  
pp. 753 ◽  
Author(s):  
Erik Berg ◽  
Tuula H. Sarvas ◽  
Alf Harbitz ◽  
Svein Erik Fevolden ◽  
Arnt Børre Salberg
Keyword(s):  
Visual Inspection ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Complete Separation ◽  
Arctic Cod ◽  
Genetic Method ◽  
North East ◽  
Accuracy And Precision ◽  
Growth Zones ◽  
The Difference

The distinction between north-east Arctic cod and Norwegian coastal cod, two major groups of Atlantic cod (Gadus morhua L.), has for many years been based on different distance and shape similarities between the two first translucent growth zones in the otoliths, subjectively decided by visual inspection in a binocular. To analyse the certainty of this technique, four independent readers have classified 263 cod otoliths in total from five different geographical areas. For three of the readers, between 82% and 89% of the classification results coincided with independent results based on genetic analyses. Further, 38 cod otoliths, where the readers were certain of the classification (21 north-east Arctic cod and 17 coastal cod) were classified by several image analysis methods. A complete separation was obtained by using the ratio of the circumferences of the two zones, providing a typical ratio of approximately 2 for coastal and 1.5 for north-east Arctic cod. The otolith method for separating the two types of cod has been considered adequately accurate in assessing the two stocks of cod. However, the method is sensitive to subjective interpretation, and action needs to be taken to minimise the difference in interpretation among otolith readers.

Small-scale temporal and spatial variation in Atlantic cod (Gadus morhua) life history

2003 ◽  
Vol 60 (9) ◽  
pp. 1111-1121 ◽  
Author(s):  
Tara M McIntyre ◽  
Jeffrey A Hutchings
Keyword(s):  
Body Mass ◽  
Life Histories ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Spatial Scales ◽  
Gonadosomatic Index ◽  
Small Scale ◽  
Hepatosomatic Index ◽  
Georges Bank ◽  
High Fecundity

Life histories of Atlantic cod (Gadus morhua) from the Gulf of St. Lawrence south to Georges Bank differ significantly through time and space. Within the Southern Gulf, fecundity per unit body mass differed by more than 40% over short (2 years) and long (42–45 years) periods of time. Significant variation in size-specific fecundity is also evident among populations: Southern Gulf cod produce almost 30% more eggs per unit body mass than those on Georges Bank, whereas fecundity of Scotian Shelf cod is almost half that of cod in Sydney Bight. Compared with those on Georges Bank, Southern Gulf cod life histories are characterized by high fecundity, late maturity, high gonadosomatic index, and large eggs. Relative to the influence of body size, neither temporal nor spatial differences in fecundity can be attributed to physiological condition, as reflected by liver weight, hepatosomatic index, and Fulton's K. Delayed maturity and higher reproductive allotment among Southern Gulf cod can be explained as selection responses to slower growth, higher prereproductive mortality, and fewer lifetime reproductive events. Patterns of covariation in heritable, fitness-related traits suggest the existence of adaptive variation and evolutionarily significant units at spatial scales considerably smaller than the species range in the Northwest Atlantic.

Substock variation in reproductive traits in North Sea cod (Gadus morhua)

2010 ◽  
Vol 67 (5) ◽  
pp. 866-876 ◽  
Author(s):  
Marion Harrald ◽  
Peter J. Wright ◽  
Francis C. Neat
Keyword(s):  
Spatial Variation ◽  
North Sea ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Liver Weight ◽  
Adaptive Divergence ◽  
Female Size ◽  
Common Environment ◽  
Relative Liver Weight ◽  
Trade Offs

The North Sea stock of Atlantic cod ( Gadus morhua ) is comprised of a number of subcomponents that differ both genetically and phenotypically. A potential cause for such spatial variability is adaptive divergence, which may be linked to differences in thermal environment and (or) historical fishing pressure. Here we present evidence that spatial variation in maturity–size relationships in the wild has a significant intrinsic component. Using a common-environment experiment on wild-caught juveniles raised through to maturity, we demonstrate that cod from the southern North Sea (SNS) mature at larger sizes than those from the northwestern North Sea (NWNS) despite broadly similar growth rates. Consistent with these experimental results, year-class-specific maturity ogives for recent maturing year classes (1999–2001) suggested that the length at which 50% of females reached maturity was 11 cm greater for SNS than for NWNS cod. Under a common environment, smaller female size at maturity partly reflected higher relative liver weight, with NWNS females having a higher relative liver weight than SNS females. By investigating maturation under controlled conditions, our study provides evidence for life history trade-offs in energy allocation between growth, energy storage, and reproduction that may underlie the spatial variation observed in the field.

Physiological basis of metabolic trade-offs between growth and performance among different strains of rainbow trout

2016 ◽  
Vol 73 (10) ◽  
pp. 1493-1506 ◽  
Author(s):  
David Allen ◽  
Jordan Rosenfeld ◽  
Jeffrey Richards
Keyword(s):  
Rainbow Trout ◽  
Metabolic Rate ◽  
Energy Content ◽  
Environmental Gradients ◽  
High Growth ◽  
Growth Efficiency ◽  
Standard Metabolic Rate ◽  
Physiological Basis ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Trade Offs

Adaptive trade-offs define the trait combinations that differentiate taxa and allow coexistence along environmental gradients. To understand the physiological trade-offs associated with growth, we examined relationships among metabolic rate, digestive capacity, tissue energy content, and growth in juveniles of three strains of rainbow trout (Oncorhynchus mykiss) that differ in growth. Fish were reared under satiation, 1% of body mass per day, and complete food deprivation treatments to assess differences in performance and adaptive trade-offs along a gradient of resource availability. The fast-growing hatchery strain had higher standard metabolic rate (SMR), lower aerobic scope, and potentially lower maximum metabolic rates, suggesting that high growth trades off against a reduced capacity to do metabolic work. Trout with high growth rates also generally had larger gastrointestinal tracts, maximum food consumption, and growth efficiency. Results demonstrate (i) higher SMR of fast growers appears to be related to a greater investment in high-maintenance digestive tissue that supports rapid growth; (ii) growth appears to trade off against active metabolism; and (iii) selection on growth involves a suite of integrated physiological and anatomical traits that are affected by both genotype and environment (ration).

scholarly journals Aerobic scope explains individual variation in feeding capacity

2015 ◽  
Vol 11 (11) ◽  
pp. 20150793 ◽  
Author(s):  
Sonya K. Auer ◽  
Karine Salin ◽  
Graeme J. Anderson ◽  
Neil B. Metcalfe
Keyword(s):  
Food Availability ◽  
Performance Measures ◽  
Salmo Trutta ◽  
High Standard ◽  
Standard Metabolic Rate ◽  
Aerobic Scope ◽  
Improve Performance ◽  
Low Levels ◽  
The Difference ◽  
Juvenile Brown Trout

Links between metabolism and components of fitness such as growth, reproduction and survival can depend on food availability. A high standard metabolic rate (SMR; baseline energy expenditure) or aerobic scope (AS; the difference between an individual's maximum and SMR) is often beneficial when food is abundant or easily accessible but can be less important or even disadvantageous when food levels decline. While the mechanisms underlying these context-dependent associations are not well understood, they suggest that individuals with a higher SMR or AS are better able to take advantage of high food abundance. Here we show that juvenile brown trout ( Salmo trutta ) with a higher AS were able to consume more food per day relative to individuals with a lower AS. These results help explain why a high aerobic capacity can improve performance measures such as growth rate at high but not low levels of food availability.

scholarly journals Vertical migration in adult Atlantic cod (Gadus morhua)

2007 ◽  
Vol 64 (12) ◽  
pp. 1747-1760 ◽  
Author(s):  
Espen Strand ◽  
Geir Huse
Keyword(s):  
Vertical Migration ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Pelagic Zone ◽  
Neutral Buoyancy ◽  
Visual Predation ◽  
Trade Offs ◽  
Key Factor ◽  
Pelagic Prey ◽  
Benthic Prey

We investigate the trade-offs associated with vertical migration and swimming speed of Atlantic cod (Gadus morhua) using an adaptive individual-based model. Simulations with varying distribution and occurrence of prey, with and without swimbladder constraints, and visual predation were performed. Most simulations resulted in cod migrations between the bottom and pelagic zones. In simulations with high probability of encountering pelagic prey, the cod spent the daytime in the pelagic zone, moving to the bottom to feed only when no pelagic prey were encountered. At night the cod stayed in the pelagic zone to attain neutral buoyancy. In simulations with low occurrence of pelagic prey or high visual predation pressure, the cod remained at the bottom feeding on the consistently present benthic prey. If the pelagic prey occurred far above the sea floor or there were no benthic prey, the cod abandoned all bottom contact. The study thus predicts that the probability of encountering energy-rich pelagic prey is the key factor in driving vertical migration in adult cod. Buoyancy regulation is further shown to be an important constraint on vertical migration.

scholarly journals Trade-offs between growth and reproduction in wild Atlantic cod

2014 ◽  
Vol 71 (7) ◽  
pp. 1106-1112 ◽  
Author(s):  
Arild Folkvord ◽  
Christian Jørgensen ◽  
Knut Korsbrekke ◽  
Richard D.M. Nash ◽  
Trygve Nilsen ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Life History Strategy ◽  
Skipped Spawning ◽  
Growth Increments ◽  
Trade Offs ◽  
Survival And Reproduction ◽  
Size At Age ◽  
Allocation Strategies ◽  
Growth And Reproduction

Animals partition and trade off their resources between competing needs such as growth, maintenance, and reproduction. Over a lifetime, allocation strategies should result in distinct trajectories for growth, survival, and reproduction, but such longitudinal individual data are difficult to reconstruct for wild animals and especially marine fish. We were able to reconstruct two of these trajectories in wild-caught Northeast Arctic cod (Gadus morhua) females: size-at-age was back-calculated from otolith growth increments, and recent spawning history was reconstructed from postovulatory follicles and present oocyte development. Our findings indicate distinct trade-offs between length growth and reproduction. Fish that sexually matured early had attained a larger size at age 3 than immatures, but onset of reproduction caused slower growth compared with immatures. We found that 6- and 7-year-old females skipping spawning grew significantly more in the year of missed spawning than females spawning for the second consecutive year. The latter tentatively supports the hypothesis that skipped spawning may occur as an adaptive life-history strategy, given the potential future fecundity gain with increased size.

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