Surfacers change their dive tactics depending on the aim of the dive: evidence from simultaneous measurements of breaths and energy expenditure

Anthropogenic disturbance of farmed animals can be detrimental by adversely affecting behaviours and metabolic rate, potentially reducing their commercial value. However, relatively little is known about the normal behavioural time budgets and associated metabolism of many such species, particularly for example pectinid bivalves, which use anaerobic metabolism during periods of short-burst activity. In the present study, we used the accelerometry technique to measure scallop overall dynamic body acceleration in combination with respirometry in order to obtain and compare the behavioural time budgets and associated metabolism of 10 scallops, Pecten maximus , in an aquaculture hatchery and 10 in the wild. Scallops in the wild typically spent only 0.1 per cent of the time moving (less than 2 min d −1 ), yet, on average, the estimated metabolism of such movement represented 16.8 per cent of daily energy expenditure. Furthermore, owing to their reliance on anaerobic pathways during such activity, movement resulted in the wild scallops having a raised metabolic rate for, on average, an estimated 7.8 per cent of the time, during which oxygen debts accumulated during movement were paid off. Hatchery scallops also typically spent only 0.1 per cent of the time moving but estimated metabolism of such movement represented 41.8 per cent of daily energy expenditure. Estimated mean daily metabolism of scallops in the hatchery was significantly higher than scallops in the wild (169.1 versus 120.7 mg O 2 d −1 ) because anthropogenic disturbance in the hatchery caused energetically costly non-feeding behaviours. Consequently, hatchery scallops also spent a far greater amount of time with a raised metabolic rate (an estimated 26.6% of the time) than wild scallops. While short-term bursts of movement in pectinid bivalves may appear innocuous, they result in large expenditures of energy and an oxygen debt that is paid off over long periods of time that together limit further movement. These findings have implications for the farming industry; mitigating anthropogenic disturbances to farmed colonies may minimize non-feeding behaviours and hence maximize growth rates by reducing the costs of such movements and increasing the opportunity to feed.

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Colour vision of green turtle (Chelonia mydas) hatchlings: Do they still prefer blue under water?

10.7287/peerj.preprints.26642v1 ◽

2018 ◽

Author(s):

Rebecca Jehne Hall ◽

Simon KA Robson ◽

Ellen Ariel

Keyword(s):

Choice Experiment ◽

Colour Vision ◽

Chelonia Mydas ◽

Light Sources ◽

Anatomical Studies ◽

Green Turtles ◽

Colour Plate ◽

In The Wild ◽

Behavioural Experiments ◽

Colour Saturation

Background. Several anatomical studies have concluded that green turtles (Chelonia mydas) possess the necessary anatomy for colour vision. Behavioural experiments were conducted with newly emerged hatchlings, testing their attraction towards light sources of different colours on their journey into the ocean. It was concluded that they are attracted to shorter wavelengths compared to longer ones, suggesting a possible attraction towards blue. Methods. Forty-one green turtles at six months of age were tested for their colour discrimination capabilities during a three-choice experiment under water. Three colours were selected for experimentation: blue, yellow, and red. Four different saturations (25, 50, 75, and 100%) of each of these colours were created, in total 12 colours were tested. The colour stimuli was printed and laminated paper colour blocks with food attached to force an interaction. Turtles were individually placed into their housing tanks with three different colours in front of them, from the same level saturation. The colour of the colour plate first approached and bitten by the turtle was noted. Results. The colour of the plate significantly influenced the likelihood that one food plate was selected more than another. Overall blue was selected 66.1%, yellow 18.2% and red 15.7%. There was also a significant interaction between the colour plate selected and the colour of the housing tank. Discussion.The findings of this study are consistent with previous research, concluding that green turtles are attracted to shorter wavelength colours, blue, compared to longer wavelength colours such as yellow or red. As the colour saturation changed and the colours became darker, turtles still chose food from the blue plates compared to the other options. These results indicate an attraction towards the colour blue, and as these research animals have never been in the wild, it is suggested that this attraction be an innate behavioural characteristic for green turtles.

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The energetic cost of copulation in a polygynandrous millipede

Journal of Experimental Biology ◽

10.1242/jeb.201.11.1847 ◽

1998 ◽

Vol 201 (11) ◽

pp. 1847-1849

Author(s):

SR Telford ◽

PI Webb

Keyword(s):

Oxygen Consumption ◽

Energy Expenditure ◽

Physical Restraint ◽

Cost Of Reproduction ◽

Energetic Cost ◽

Significant Cost ◽

Mating Patterns ◽

Invertebrate Species ◽

Rate Of Oxygen Consumption ◽

In The Wild

We determined the energetic cost of copulation in both sexes of Alloporus uncinatus, a polygynandrous millipede in which copulation can last for several hours and involves physical restraint of the female by the male. We found an elevation in the rate of oxygen consumption by males and a depression in the rate of oxygen consumption by females during copulation. The rate of oxygen consumption of females, but not of males, was elevated immediately after copulation, indicating that females had built up and were repaying an oxygen debt. On this basis, we estimated energy expenditure during copulation to be 30 % above resting levels in males and 14 % above resting levels in females. As matings are frequent in this species in the wild throughout the 4 month breeding season, we suggest that the energetic demands of copulation are a previously overlooked potentially significant cost of reproduction in this species and in other invertebrate species with similar mating patterns.

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Incubation temperature, energy expenditure and hatchling size in the green turtle (Chelonia mydas), a species with temperature-sensitive sex determination

Australian Journal of Zoology ◽

10.1071/zo01006 ◽

2001 ◽

Vol 49 (4) ◽

pp. 389 ◽

Cited By ~ 62

Author(s):

David T. Booth ◽

Katherine Astill

Keyword(s):

Oxygen Consumption ◽

Production Cost ◽

Incubation Temperature ◽

Chelonia Mydas ◽

Temperature Sensitive ◽

Barrier Reef ◽

Body Dimensions ◽

Green Turtles ◽

The Difference ◽

Hatchling Size

Eggs from the Heron Island, Great Barrier Reef, nesting population of green turtles (Chelonia mydas) were incubated at all-male-determining (26˚C) and all-female-determining (30˚C) temperatures. Oxygen consumption and embryonic growth were monitored throughout incubation, and hatchling masses and body dimensions were measured from both temperatures. Eggs hatched after 79 and 53 days incubation at 26˚C and 30˚C respectively. Oxygen consumption at both temperatures increased to a peak several days before hatching, a pattern typical of turtle embryos, and the rate of oxygen was higher at 30˚C than 26˚C. The total amount of energy consumed during incubation, and hatchling dimensions, were similar at both temperatures, but hatchlings from 26˚C had larger mass, larger yolk-free mass and smaller residual yolks than hatchlings from 30˚C. Because of the difference in mass of hatchlings, hatchlings from 30˚C had a higher production cost.

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Energy expenditure of freely swimming adult green turtles (Chelonia mydas) and its link with body acceleration

Journal of Experimental Biology ◽

10.1242/jeb.062943 ◽

2011 ◽

Vol 214 (23) ◽

pp. 4010-4020 ◽

Cited By ~ 40

Author(s):

M. R. Enstipp ◽

S. Ciccione ◽

B. Gineste ◽

M. Milbergue ◽

K. Ballorain ◽

...

Keyword(s):

Energy Expenditure ◽

Chelonia Mydas ◽

Body Acceleration ◽

Green Turtles

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Colour vision of green turtle (Chelonia mydas) hatchlings: Do they still prefer blue under water?

10.7287/peerj.preprints.26642 ◽

2018 ◽

Author(s):

Rebecca Jehne Hall ◽

Simon KA Robson ◽

Ellen Ariel

Keyword(s):

Choice Experiment ◽

Colour Vision ◽

Chelonia Mydas ◽

Light Sources ◽

Anatomical Studies ◽

Green Turtles ◽

Colour Plate ◽

In The Wild ◽

Behavioural Experiments ◽

Colour Saturation

Background. Several anatomical studies have concluded that green turtles (Chelonia mydas) possess the necessary anatomy for colour vision. Behavioural experiments were conducted with newly emerged hatchlings, testing their attraction towards light sources of different colours on their journey into the ocean. It was concluded that they are attracted to shorter wavelengths compared to longer ones, suggesting a possible attraction towards blue. Methods. Forty-one green turtles at six months of age were tested for their colour discrimination capabilities during a three-choice experiment under water. Three colours were selected for experimentation: blue, yellow, and red. Four different saturations (25, 50, 75, and 100%) of each of these colours were created, in total 12 colours were tested. The colour stimuli was printed and laminated paper colour blocks with food attached to force an interaction. Turtles were individually placed into their housing tanks with three different colours in front of them, from the same level saturation. The colour of the colour plate first approached and bitten by the turtle was noted. Results. The colour of the plate significantly influenced the likelihood that one food plate was selected more than another. Overall blue was selected 66.1%, yellow 18.2% and red 15.7%. There was also a significant interaction between the colour plate selected and the colour of the housing tank. Discussion.The findings of this study are consistent with previous research, concluding that green turtles are attracted to shorter wavelength colours, blue, compared to longer wavelength colours such as yellow or red. As the colour saturation changed and the colours became darker, turtles still chose food from the blue plates compared to the other options. These results indicate an attraction towards the colour blue, and as these research animals have never been in the wild, it is suggested that this attraction be an innate behavioural characteristic for green turtles.

Download Full-text