Evidence for the Assumption of Independence between Gastric Emptying Rate and Swimming Activity Using Atlantic Cod, Gadus morhua

1977 ◽  
Vol 34 (12) ◽  
pp. 2411-2413 ◽  
Author(s):  
A. V. Tyler
Keyword(s):  
Gastric Emptying ◽  
Key Words ◽  
Swimming Speed ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Swimming Activity ◽  
Rate Data ◽  
Gastric Emptying Rate ◽  
Digestion Rate ◽  
Sufficient Magnitude

Juvenile Atlantic cod, Gadus morhua, were forced to swim at speeds of 0.07, 0.6, and 1.2 body lengths/s after eating measured quantities of food. Higher speeds could not be maintained for more than 2 days. Only the highest speed caused a decrease in gastric emptying rate, but the decrease was not of sufficient magnitude to interfere with ration estimates based on digestion rate data. Key words: feeding, swimming speed, digestion rate

Factors affecting the swimming endurance and catchability of Atlantic cod (Gadus morhua)

2000 ◽  
Vol 57 (6) ◽  
pp. 1200-1207 ◽  
Author(s):  
Paul D Winger ◽  
Pingguo He ◽  
Stephen J Walsh
Keyword(s):  
Swimming Speed ◽  
Newfoundland And Labrador ◽  
Gadus Morhua ◽  
Failure Time ◽  
Atlantic Cod ◽  
Fish Length ◽  
Time Analysis ◽  
Factors Affecting ◽  
Highly Sensitive ◽  
Swimming Endurance

The swimming endurance of Atlantic cod (Gadus morhua), native to the cold waters off the east coast of Newfoundland and Labrador, was investigated under laboratory conditions. Using a swimming flume, endurance was tested at swimming speeds ranging from 0.6 to 1.3 m·s-1 using water temperatures from 0.0 to 9.8°C ( mean = 3.2°C, SD = 2.8) and fish lengths from 41.0 to 86.0 cm ( mean = 57.8 cm, SD = 10.5). The results revealed that swimming speed was the only significant factor affecting the endurance of cod. The maximum sustained swimming speed (Ums) was predicted to be 0.66 m·s-1. Statistical analysis of the data was conducted using failure time analysis. The hazard, or risk of exhaustion, was found to increase rapidly with increasing swimming speed, i.e., there was a decrease in the probability of cod achieving a given swimming endurance. Probability curves for the endurance of cod were calculated for different swimming speeds. The findings suggest that the catching efficiency of commercially targeted cod (>41.0 cm) by otter trawls may be highly sensitive to changes in towing speed while being independent of both fish length and water temperature.

Potential methods for measuring the activity patterns and energy use of Atlantic cod (Gadus morhua)

2009 ◽  
Vol 66 (7) ◽  
pp. 1095-1106 ◽  
Author(s):  
Matthew J. Gollock ◽  
Kristopher J. Hunter ◽  
Douglas A. Syme ◽  
Marcus Freeman ◽  
R. Scott McKinley ◽  
...  
Keyword(s):  
Swimming Speed ◽  
Gadus Morhua ◽  
Energy Use ◽  
Atlantic Cod ◽  
Activity Patterns ◽  
Strong Relationship ◽  
Marine Species ◽  
Free Swimming ◽  
Cost Of Transport ◽  
Wide Range

As there are no commercially available acoustic telemetry devices for quantifying the swimming activity and activity-related metabolic expenditures of a wide range of marine species, we (i) examined the suitability of three methods (electromyography; sonomicrometry; and tail differential pressure tags (DPT)) for measuring the swimming speed of Atlantic cod ( Gadus morhua ), and indirectly, metabolic rate (MO2) and (ii) measured the activity pattern of free-swimming cod carrying the DPT. All three methods yielded significant relationships with swim speed during a critical swimming speed (Ucrit) test. However, only the DPT was able to discern between swimming speed differences of 0.1 body lengths (BL)·s–1 and provide a strong relationship with MO2. Further, we found that free-swimming cod fitted with the DPT swam at an average speed of 0.33 BL·s–1, the speed previously reported to result in minimal cost of transport for this species. While the DPT has considerable potential for assessing the bioenergetics of marine fishes, the swimming economy of tagged Atlantic cod was lower above 0.4 BL·s–1 as compared with untagged fish, and Ucrit was reduced by 25%. These latter effects are likely related to the tag’s present size (39 g) and design.

SPONTANEOUS SWIMMING ACTIVITY OF ATLANTIC COD GADUS MORHUA EXPOSED TO GRADED HYPOXIA AT THREE TEMPERATURES

1994 ◽  
Vol 197 (1) ◽  
pp. 129-142 ◽  
Author(s):  
H Schurmann ◽  
J Steffensen
Keyword(s):  
Oxygen Saturation ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Swimming Activity ◽  
Activity Level ◽  
Effect Of Temperature ◽  
Hypoxic Environment ◽  
Animal Activity ◽  
Hypoxic Water ◽  
Computerized System

The spontaneous swimming activity of Atlantic cod Gadus morhua was investigated at graded levels of hypoxia at three temperatures (5, 10 and 15 °C) by using a computerized system monitoring animal activity. The fish were tested individually, and swimming distance was used as a measure of activity. No significant effect of temperature on swimming distance in normoxic water was found. At all temperatures, activity level decreased with decreasing oxygen saturation. Swimming behaviour at normoxia and 50 % and 25 % oxygen saturation is described. No apparent avoidance of hypoxic water was found based on the distribution of swimming speeds and turning angles. The possible benefits of a decreased activity level in a hypoxic environment are discussed.

Cardiac output as a predictor of metabolic rate in cod gadus morhua

1998 ◽  
Vol 201 (19) ◽  
pp. 2779-2789 ◽  
Author(s):  
DM Webber ◽  
RG Boutilier ◽  
SR Kerr
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Swimming Speed ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Rate Of Oxygen Consumption ◽  
Free Ranging ◽  
The Relationship ◽  
Fisheries Biology

Adult Atlantic cod (2 kg Gadus morhua) were fitted with Doppler ultrasonic flow-probes to measure ventral aortic outflow (i.e. cardiac output). The probes remained patent for upwards of 3 months, during which time detailed relationships between cardiac output (), heart rate (fh) and rate of oxygen consumption (O2) were determined as a function of swimming speed and temperature (5 degreesC and 10 degreesC). The rate of oxygen consumption increased linearly with and exponentially with swimming speed. A very good correlation was observed between O2 and (r2=0.86) compared with the correlation between O2 and fh (r2=0.50 for all 10 degreesC data and r2=0.86 for all 5 degreesC data). However, the O2 versus fh correlation gradually improved over approximately 1 week after surgery (r2=0.86). The relationship between O2 and was independent of temperature, while the relationship between O2 and fh changed with temperature. Hence, calculating O2 from is simpler and does not require that temperature be recorded simultaneously. Variations in cardiac output were determined more by changes in stroke volume (Vs) than by fh; therefore, fh was a less reliable predictor of metabolic rate than was . Given that can be used to estimate O2 so faithfully, the advent of a cardiac output telemeter would enable robust estimates to be made of the activity metabolism of free-ranging fish in nature, thereby strengthening one of the weakest links in the bioenergetic models of fisheries biology.

Rates of Gastric Emptying in Young Cod

1970 ◽  
Vol 27 (7) ◽  
pp. 1177-1189 ◽  
Author(s):  
A. V. Tyler
Keyword(s):  
Gastric Emptying ◽  
Food Intake ◽  
Intestinal Absorption ◽  
Gastric Volume ◽  
Acclimation Temperature ◽  
Rate Data ◽  
Time Intervals ◽  
Digestion Rate ◽  
Straight Line ◽  
Depletion Rate

Stomachs of young cod were opened at various time intervals after they had voluntarily eaten measured meals. More digested food left the stomach in the first few hours after the meal was given than towards the end of digestion. Instantaneous depletion rate increased rapidly with increase in acclimation temperature from 2 to 15 C. The rate was not increased at 19 C and was possibly depressed. Fish would not feed at 21 C. When meal size was varied, a straight-line relation was found between rate of gastric emptying and quantity of food in the stomach. This implies that in young cod intestinal absorption is coupled to food intake by regulation of the gastric volume. It is likely that digestion rate data could be used to estimate daily rations for fish in their own environment by measuring quantity of food in the stomach.

Glycogen and Lactic Acid Concentrations in Atlantic Cod (Gadus morhua) in Relation to Exercise

1968 ◽  
Vol 25 (5) ◽  
pp. 837-851 ◽  
Author(s):  
F. W. H. Beamish
Keyword(s):  
Lactic Acid ◽  
Swimming Speed ◽  
Muscle Glycogen ◽  
Similar Pattern ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Recovery Period ◽  
Strenuous Exercise ◽  
Before And After ◽  
Exercise Muscle

In Atlantic cod, muscle glycogen was reduced by about 50% at moderate swimming speeds and over 80% at higher speeds. Muscle glycogen for a given swimming speed was generally lower after 30 min exercise than after 15 min exercise. During the 8-hr period after strenuous exercise, muscle glycogen increased but remained well below the level for unexercised fish.At moderate swimming speeds, fish exhibited comparatively small amounts of muscle and blood lactic acid. At higher swimming speeds, fish accumulated significantly larger quantities of lactic acid in the muscle and blood. During the recovery period after strenuous exercise, muscle and blood lactic acid increased precipitously. Muscle lactic acid remained high for 1 hr after exercise and then decreased in 8 hr to levels similar to those of unexercised cod. Blood lactic acid followed a similar pattern except that it continued to increase for 1.5 hr after exercise.Serial samples of blood taken before and after 30 min strenuous exercise showed marked differences in lactic acid among individuals. Blood lactic acid usually continued to increase for 30–60 min after exercise, and decreased to the level for unexercised fish about 24 hr after exercise.No mortalities attributable to muscular fatigue occurred among cod.

Swimming Endurance of Some Northwest Atlantic Fishes

1966 ◽  
Vol 23 (3) ◽  
pp. 341-347 ◽  
Author(s):  
F. W. H. Beamish
Keyword(s):  
Swimming Speed ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Northwest Atlantic ◽  
Sea Raven ◽  
Longhorn Sculpin ◽  
Hemitripterus Americanus ◽  
Swimming Endurance

Endurance was determined in relation to swimming speed and temperature for Atlantic cod, Gadus morhua Linnaeus, redfish, Sebastes marinus (Linnaeus), winter flounder, Pseudopleuronectes americanus (Walbaum), and to swimming speed at 8 C for longhorn sculpin, Myoxocephalus octodecimspinosus (Mitchill), sea raven, Hemitripterus americanus (Gmelin), and ocean pout, Macrozoarces americanus (Block and Schneider).In an activity chamber at a swimming speed of 4 body lengths per second (BL/sec) Atlantic cod swam for about equally long periods at 5 and 8 C, and redfish and winter flounder each about equally long at 5, 8, and 11 C. The pattern was similar for higher speeds. At 14 C winter flounder swam longer at 6 BL/sec than at the lower temperatures. For swimming speeds less than 4 BL/sec all species swam longer at the higher temperatures. At 8 C, the only temperature at which all species were tested, endurance at comparable swimming speeds was greatest for winter flounder, followed by cod, redfish, longhorn sculpin, ocean pout, and sea raven.

Caudal differential pressure as a predictor of swimming speed of cod (Gadus morhua)

2001 ◽  
Vol 204 (20) ◽  
pp. 3561-3570
Author(s):  
D. M. Webber ◽  
R. G. Boutilier ◽  
S. R. Kerr ◽  
M. J. Smale
Keyword(s):  
Oxygen Consumption ◽  
Swimming Speed ◽  
Pressure Difference ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Activity Patterns ◽  
Total Body Length ◽  
Differential Pressure ◽  
Rate Of Oxygen Consumption ◽  
Highly Correlated

SUMMARY We report the results of an experiment designed to investigate the feasibility of using differential pressure to estimate the swimming speed and metabolic rate of Atlantic cod (Gadus morhua). Seven cod were fitted with a miniature differential pressure sensor mounted on one side of the caudal peduncle immediately anterior to the base of the caudal fin rays. Relationships between differential pressure, tailbeat frequency, tailbeat amplitude, swimming speed and rate of oxygen consumption (ṀO2) were determined as a function of the swimming speed of cod swimming at 5°C in a recirculating ‘Brett-style’ respirometer. Tailbeat differential pressure, tailbeat amplitude and tailbeat frequency were highly correlated with swimming speed. The average or integrated pressure ranged from 0 to 150 Pa for speeds up to 0.8 m s–1 (1.1 L s–1, where L is total body length), while the ‘pressure difference’ (maximum minus minimum pressure) ranged from 0 to 900 Pa. Small changes in swimming speed of less than 0.05 m s–1 were readily detected as differences in tailbeat pressure. Burst swimming in the respirometer resulted in huge pressure ‘bursts’ of up to 5000 Pa ‘pressure difference’. The rate of oxygen consumption increased exponentially and was highly correlated with swimming speed (r2=0.77). The rate of oxygen consumption was also correlated with tailbeat integrated pressure (r2=0.68) and with differential pressure (r2=0.43); regression correlations were always greater for individuals than for combined data from all cod. The results detailed in this study indicate that an ultrasonic differential pressure transmitter would enable accurate estimates of the swimming speed, rates of oxygen consumption and activity patterns of free-ranging fish in nature.

Swimming Speed and Swimming Metabolism of Atlantic Cod (Gadus morhua) in Relation to Available Food: A Laboratory Study

1993 ◽  
Vol 50 (12) ◽  
pp. 2542-2551 ◽  
Author(s):  
Björn Björnsson
Keyword(s):  
Food Intake ◽  
Laboratory Study ◽  
Swimming Speed ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Active Group ◽  
Energetic Cost ◽  
Live Fish ◽  
The Mean ◽  
Maintenance Ration

A laboratory study was performed on how young Atlantic cod (Gadus morhua) regulate their swimming speed according to available food. A circular tank 15 m in diameter was divided into six sectors, each containing two cod ranging in length from 29 to 42 cm. Live fish 5 cm long on average were used as prey. For the first 48 d food intake was changed every 1 or 2 wk equally for all six groups. During the last 31 d each group received different amounts of food. The mean swimming speed was highest (0.6 bl/s) when food intake was about half the maximum intake and lowest (0.2 bl/s) when food was unlimited or not available. Swimming metabolism was related to food intake in a similar way, but with a larger difference between the most active (50 mg O2∙kg−1∙h−1) and the least active group (10 mg O2∙kg−1∙h−1). Maximum sustained swimming metabolism was estimated to be about 0.6 times the standard metabolism. The estimated energetic cost of swimming as a percentage of energy obtained from the food decreased with food intake from 24% at maintenance ration to 2% at maximum food intake. On a log–log plot swimming speed decreased linearly with time after encounter of prey.

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