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Douglas B Noltie - One of the best experts on this subject based on the ideXlab platform.
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group holding impedes compensatory growth of hybrid Sunfish
Aquaculture, 2000Co-Authors: Robert S Hayward, Ning Wang, Douglas B NoltieAbstract:An earlier study with a repeating no-feed/refeed schedule (D2 schedule) elicited compensatory growth (CG) in age-0 hybrid Sunfish (F1: female green Sunfish, Lepomis cyanellus×male bluegill L. macrochirus) held individually and fed ad libitum on feeding days. Weight gain under these conditions exceeded that of daily-fed controls. The present study sought to determine whether similar growth improvement would result when hybrid Sunfish were held in groups and fed to satiation on the D2 schedule. In Experiment 1, age-0 hybrid Sunfish were held in groups of 10 fish per 25-l chamber at 24°C and fed four times daily to apparent satiation on feeding days. Under this regime, fish fed according to the D2 schedule gained less weight than the controls (P<0.10). Experiment 2 was run in an effort to duplicate the results of the previous study. When age-0 fish were held individually at 24°C and fed ad libitum on feeding days, those fed on the D2 schedule gained significantly more weight (P<0.10) than the controls. These results indicate that group holding in combination with satiation feeding impedes the full expression of the CG capacity of hybrid Sunfish. The major impediment under group holding may be the negative effects of social interactions on food consumption and growth efficiency.
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effect of feeding frequency on food consumption growth size variation and feeding pattern of age 0 hybrid Sunfish
Aquaculture, 1998Co-Authors: Ning Wang, Robert S Hayward, Douglas B NoltieAbstract:Four treatment groups of age-0 hybrid Sunfish (female green Sunfish Lepomis cyanellus×male bluegill L. macrochirus) were fed to satiation at one of four frequencies (one, two, three or four meals per day) for 30 days. Fish fed three and four times daily showed the greatest consumption and growth rates; food conversion ratios did not differ among the four treatments (P>0.05). Because growth and food conversion were not enhanced when feeding was increased from three to four times daily, the optimal feeding frequency for growth was considered to be three times per day. However, the extent of inter-individual size variation (% change in CV) declined with increasing number of daily feedings (P<0.05), suggesting that more frequent feeding may produce fish of more uniform sizes. Daily feeding patterns also changed in response to feeding frequency, indicating that when fish are fed at a particular frequency, knowledge of feeding pattern is necessary so that appropriate food amounts can be supplied at each provisioning. Our results suggest that an optimal feeding frequency should be determined not only on the basis of growth and food conversion efficiency, but also according to influences of daily feeding pattern and the desire to achieve size uniformity.
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effect of feeding frequency on food consumption growth size variation and feeding pattern of age 0 hybrid Sunfish
Aquaculture, 1998Co-Authors: Ning Wang, Robert S Hayward, Douglas B NoltieAbstract:Abstract Four treatment groups of age-0 hybrid Sunfish (female green Sunfish Lepomis cyanellus×male bluegill L. macrochirus) were fed to satiation at one of four frequencies (one, two, three or four meals per day) for 30 days. Fish fed three and four times daily showed the greatest consumption and growth rates; food conversion ratios did not differ among the four treatments (P>0.05). Because growth and food conversion were not enhanced when feeding was increased from three to four times daily, the optimal feeding frequency for growth was considered to be three times per day. However, the extent of inter-individual size variation (% change in CV) declined with increasing number of daily feedings (P
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use of compensatory growth to double hybrid Sunfish growth rates
Transactions of The American Fisheries Society, 1997Co-Authors: Robert S Hayward, Douglas B Noltie, Ning WangAbstract:Abstract We studied the use of compensatory growth (CG) to grow fish larger than control fish that were fed every day without restriction. Five treatment groups of 10 juvenile hybrid Sunfish (F1 hybrid of female green Sunfish Lepomis cyanellus × male bluegill L. niacrochirus) received repeating cycles of no feeding and refeeding; fixed no-feed periods of either 2, 4, 6, 10, or 14 d distinguished the treatment groups. No-feed periods elicited the CG state and were immediately followed by days of ad libitum refeeding. Refeeding periods within each treatment group (D2, D4, D6, D 10, or D14) were continued until mean daily food consumption by fish no longer exceeded that of controls fed ad libitum every day (i.e., ad libitum refeeding was continued for as long as hyperphagia persisted, then another no-feed period began). Fish in two groups, D2 and D 14, consumed more food and significantly outgrew controls by 2 and 1.4 times, respectively, in 105-d experiments. Gross growth efficiency (GGE, fish weight gained...
Ning Wang - One of the best experts on this subject based on the ideXlab platform.
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group holding impedes compensatory growth of hybrid Sunfish
Aquaculture, 2000Co-Authors: Robert S Hayward, Ning Wang, Douglas B NoltieAbstract:An earlier study with a repeating no-feed/refeed schedule (D2 schedule) elicited compensatory growth (CG) in age-0 hybrid Sunfish (F1: female green Sunfish, Lepomis cyanellus×male bluegill L. macrochirus) held individually and fed ad libitum on feeding days. Weight gain under these conditions exceeded that of daily-fed controls. The present study sought to determine whether similar growth improvement would result when hybrid Sunfish were held in groups and fed to satiation on the D2 schedule. In Experiment 1, age-0 hybrid Sunfish were held in groups of 10 fish per 25-l chamber at 24°C and fed four times daily to apparent satiation on feeding days. Under this regime, fish fed according to the D2 schedule gained less weight than the controls (P<0.10). Experiment 2 was run in an effort to duplicate the results of the previous study. When age-0 fish were held individually at 24°C and fed ad libitum on feeding days, those fed on the D2 schedule gained significantly more weight (P<0.10) than the controls. These results indicate that group holding in combination with satiation feeding impedes the full expression of the CG capacity of hybrid Sunfish. The major impediment under group holding may be the negative effects of social interactions on food consumption and growth efficiency.
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effect of feeding frequency on food consumption growth size variation and feeding pattern of age 0 hybrid Sunfish
Aquaculture, 1998Co-Authors: Ning Wang, Robert S Hayward, Douglas B NoltieAbstract:Four treatment groups of age-0 hybrid Sunfish (female green Sunfish Lepomis cyanellus×male bluegill L. macrochirus) were fed to satiation at one of four frequencies (one, two, three or four meals per day) for 30 days. Fish fed three and four times daily showed the greatest consumption and growth rates; food conversion ratios did not differ among the four treatments (P>0.05). Because growth and food conversion were not enhanced when feeding was increased from three to four times daily, the optimal feeding frequency for growth was considered to be three times per day. However, the extent of inter-individual size variation (% change in CV) declined with increasing number of daily feedings (P<0.05), suggesting that more frequent feeding may produce fish of more uniform sizes. Daily feeding patterns also changed in response to feeding frequency, indicating that when fish are fed at a particular frequency, knowledge of feeding pattern is necessary so that appropriate food amounts can be supplied at each provisioning. Our results suggest that an optimal feeding frequency should be determined not only on the basis of growth and food conversion efficiency, but also according to influences of daily feeding pattern and the desire to achieve size uniformity.
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effect of feeding frequency on food consumption growth size variation and feeding pattern of age 0 hybrid Sunfish
Aquaculture, 1998Co-Authors: Ning Wang, Robert S Hayward, Douglas B NoltieAbstract:Abstract Four treatment groups of age-0 hybrid Sunfish (female green Sunfish Lepomis cyanellus×male bluegill L. macrochirus) were fed to satiation at one of four frequencies (one, two, three or four meals per day) for 30 days. Fish fed three and four times daily showed the greatest consumption and growth rates; food conversion ratios did not differ among the four treatments (P>0.05). Because growth and food conversion were not enhanced when feeding was increased from three to four times daily, the optimal feeding frequency for growth was considered to be three times per day. However, the extent of inter-individual size variation (% change in CV) declined with increasing number of daily feedings (P
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use of compensatory growth to double hybrid Sunfish growth rates
Transactions of The American Fisheries Society, 1997Co-Authors: Robert S Hayward, Douglas B Noltie, Ning WangAbstract:Abstract We studied the use of compensatory growth (CG) to grow fish larger than control fish that were fed every day without restriction. Five treatment groups of 10 juvenile hybrid Sunfish (F1 hybrid of female green Sunfish Lepomis cyanellus × male bluegill L. niacrochirus) received repeating cycles of no feeding and refeeding; fixed no-feed periods of either 2, 4, 6, 10, or 14 d distinguished the treatment groups. No-feed periods elicited the CG state and were immediately followed by days of ad libitum refeeding. Refeeding periods within each treatment group (D2, D4, D6, D 10, or D14) were continued until mean daily food consumption by fish no longer exceeded that of controls fed ad libitum every day (i.e., ad libitum refeeding was continued for as long as hyperphagia persisted, then another no-feed period began). Fish in two groups, D2 and D 14, consumed more food and significantly outgrew controls by 2 and 1.4 times, respectively, in 105-d experiments. Gross growth efficiency (GGE, fish weight gained...
Robert S Hayward - One of the best experts on this subject based on the ideXlab platform.
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group holding impedes compensatory growth of hybrid Sunfish
Aquaculture, 2000Co-Authors: Robert S Hayward, Ning Wang, Douglas B NoltieAbstract:An earlier study with a repeating no-feed/refeed schedule (D2 schedule) elicited compensatory growth (CG) in age-0 hybrid Sunfish (F1: female green Sunfish, Lepomis cyanellus×male bluegill L. macrochirus) held individually and fed ad libitum on feeding days. Weight gain under these conditions exceeded that of daily-fed controls. The present study sought to determine whether similar growth improvement would result when hybrid Sunfish were held in groups and fed to satiation on the D2 schedule. In Experiment 1, age-0 hybrid Sunfish were held in groups of 10 fish per 25-l chamber at 24°C and fed four times daily to apparent satiation on feeding days. Under this regime, fish fed according to the D2 schedule gained less weight than the controls (P<0.10). Experiment 2 was run in an effort to duplicate the results of the previous study. When age-0 fish were held individually at 24°C and fed ad libitum on feeding days, those fed on the D2 schedule gained significantly more weight (P<0.10) than the controls. These results indicate that group holding in combination with satiation feeding impedes the full expression of the CG capacity of hybrid Sunfish. The major impediment under group holding may be the negative effects of social interactions on food consumption and growth efficiency.
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effect of feeding frequency on food consumption growth size variation and feeding pattern of age 0 hybrid Sunfish
Aquaculture, 1998Co-Authors: Ning Wang, Robert S Hayward, Douglas B NoltieAbstract:Four treatment groups of age-0 hybrid Sunfish (female green Sunfish Lepomis cyanellus×male bluegill L. macrochirus) were fed to satiation at one of four frequencies (one, two, three or four meals per day) for 30 days. Fish fed three and four times daily showed the greatest consumption and growth rates; food conversion ratios did not differ among the four treatments (P>0.05). Because growth and food conversion were not enhanced when feeding was increased from three to four times daily, the optimal feeding frequency for growth was considered to be three times per day. However, the extent of inter-individual size variation (% change in CV) declined with increasing number of daily feedings (P<0.05), suggesting that more frequent feeding may produce fish of more uniform sizes. Daily feeding patterns also changed in response to feeding frequency, indicating that when fish are fed at a particular frequency, knowledge of feeding pattern is necessary so that appropriate food amounts can be supplied at each provisioning. Our results suggest that an optimal feeding frequency should be determined not only on the basis of growth and food conversion efficiency, but also according to influences of daily feeding pattern and the desire to achieve size uniformity.
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effect of feeding frequency on food consumption growth size variation and feeding pattern of age 0 hybrid Sunfish
Aquaculture, 1998Co-Authors: Ning Wang, Robert S Hayward, Douglas B NoltieAbstract:Abstract Four treatment groups of age-0 hybrid Sunfish (female green Sunfish Lepomis cyanellus×male bluegill L. macrochirus) were fed to satiation at one of four frequencies (one, two, three or four meals per day) for 30 days. Fish fed three and four times daily showed the greatest consumption and growth rates; food conversion ratios did not differ among the four treatments (P>0.05). Because growth and food conversion were not enhanced when feeding was increased from three to four times daily, the optimal feeding frequency for growth was considered to be three times per day. However, the extent of inter-individual size variation (% change in CV) declined with increasing number of daily feedings (P
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use of compensatory growth to double hybrid Sunfish growth rates
Transactions of The American Fisheries Society, 1997Co-Authors: Robert S Hayward, Douglas B Noltie, Ning WangAbstract:Abstract We studied the use of compensatory growth (CG) to grow fish larger than control fish that were fed every day without restriction. Five treatment groups of 10 juvenile hybrid Sunfish (F1 hybrid of female green Sunfish Lepomis cyanellus × male bluegill L. niacrochirus) received repeating cycles of no feeding and refeeding; fixed no-feed periods of either 2, 4, 6, 10, or 14 d distinguished the treatment groups. No-feed periods elicited the CG state and were immediately followed by days of ad libitum refeeding. Refeeding periods within each treatment group (D2, D4, D6, D 10, or D14) were continued until mean daily food consumption by fish no longer exceeded that of controls fed ad libitum every day (i.e., ad libitum refeeding was continued for as long as hyperphagia persisted, then another no-feed period began). Fish in two groups, D2 and D 14, consumed more food and significantly outgrew controls by 2 and 1.4 times, respectively, in 105-d experiments. Gross growth efficiency (GGE, fish weight gained...
L Sousa - One of the best experts on this subject based on the ideXlab platform.
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integrated monitoring of mola mola behaviour in space and time
PLOS ONE, 2016Co-Authors: L Sousa, Nuno Queiroz, Francisco Lopezcastejon, Javier Gilabert, Paulo Relvas, Ana Rita Couto, Renato Caldas, Paulo Sousa Dias, Hugo DiasAbstract:Over the last decade, ocean Sunfish movements have been monitored worldwide using various satellite tracking methods. This study reports the near-real time monitoring of fine-scale (< 10 m) behaviour of Sunfish. The study was conducted in southern Portugal in May 2014 and involved satellite tags and underwater and surface robotic vehicles to measure both the movements and the contextual environment of the fish. A total of four individuals were tracked using custom-made GPS satellite tags providing geolocation estimates of fine-scale resolution. These accurate positions further informed Sunfish areas of restricted search (ARS), which were directly correlated to steep thermal frontal zones. Simultaneously, and for two different occasions, an Autonomous Underwater Vehicle (AUV) video-recorded the path of the tracked fish and detected buoyant particles in the water column. Importantly, the densities of these particles were also directly correlated to steep thermal gradients. Thus, both Sunfish foraging behaviour (ARS) and possibly prey densities, were found to be influenced by analogous environmental conditions. In addition, the dynamic structure of the water transited by the tracked individuals was described by a Lagrangian modelling approach. The model informed the distribution of zooplankton in the region, both horizontally and in the water column, and the resultant simulated densities positively correlated with Sunfish ARS behaviour estimator (rs = 0.184, p<0.001). The model also revealed that tracked fish opportunistically displace with respect to subsurface current flow. Thus, we show how physical forcing and current structure provide a rationale for a predator’s fine-scale behaviour observed over a two weeks in May 2014.
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dna barcoding identifies a cosmopolitan diet in the ocean Sunfish
Scientific Reports, 2016Co-Authors: L Sousa, Raquel Xavier, Vânia Costa, Nicolas E Humphries, Clive N Trueman, Rui Rosa, David W SimsAbstract:The ocean Sunfish (Mola mola) is the world’s heaviest bony fish reaching a body mass of up to 2.3 tonnes. However, the prey M. mola consumes to fuel this prodigious growth remains poorly known. Sunfish were thought to be obligate gelatinous plankton feeders, but recent studies suggest a more generalist diet. In this study, through molecular barcoding and for the first time, the diet of Sunfish in the north-east Atlantic Ocean was characterised. Overall, DNA from the diet content of 57 individuals was successfully amplified, identifying 41 different prey items. Sunfish fed mainly on crustaceans and teleosts, with cnidarians comprising only 16% of the consumed prey. Although no adult fishes were sampled, we found evidence for an ontogenetic shift in the diet, with smaller individuals feeding mainly on small crustaceans and teleost fish, whereas the diet of larger fish included more cnidarian species. Our results confirm that smaller Sunfish feed predominantly on benthic and on coastal pelagic species, whereas larger fish depend on pelagic prey. Therefore, Sunfish is a generalist predator with a greater diversity of links in coastal food webs than previously realised. Its removal as fisheries’ bycatch may have wider reaching ecological consequences, potentially disrupting coastal trophic interactions.
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environmental influence on the seasonal movements of satellite tracked ocean Sunfish mola mola in the north east atlantic
Animal Biotelemetry, 2016Co-Authors: L Sousa, Nicolas E Humphries, David W Sims, Nuno Queiroz, Gonzalo MucientesAbstract:Determining the habitat use of mobile marine species is important for understanding responses to climate change and aids the implementation of management and conservation measures. Inference of preferred habitat use has been greatly improved by combining satellite-based oceanographic data with animal tracking techniques. Although there have been several satellite-tracking studies on ocean Sunfish Mola mola, limited information is available about either horizontal or vertical environmental preferences. In this study, both geographical movements and diving behaviour of ocean Sunfish were explored together with the environmental factors influencing this species’ space use in the north-east Atlantic. Habitat selection of electronic-tagged Sunfish (n = 22 individuals; 0.6–1.4 m total length, TL) was investigated using geolocations from Argos-linked and pop-up satellite archival transmitters. Satellite tracking (up to 171 days, mean 66 days) revealed seasonal movements: northward in spring–summer and southward in cooler months. Sunfish spent extended periods in three focal areas, the Gulf of Cadiz, north-east Iberia and the Alboran gyre, which are characterised by the presence of frontal features with elevated primary production. Habitat modelling revealed that sea surface temperature and thermal gradients significantly influenced Sunfish distribution. Diving profiles, extending from the surface to a maximum depth of 704 m, revealed different depth-use patterns not linked to geographical region or water column stratification. Overall, a size-related movement pattern was detected with larger individuals (>0.92 m TL) travelling further, exploiting greater depth ranges and spending more time at depth than smaller fish. Ocean Sunfish in the north-east Atlantic displayed seasonal movements, primarily driven by thermal preferences, extending into higher latitudes in summer. Moreover, fish also occupied productive frontal areas for long periods, presumably for improved foraging opportunities. Lastly, Sunfish showed considerable variability in diving patterns which likely reflect the tracking of planktonic prey distributions.
David W Sims - One of the best experts on this subject based on the ideXlab platform.
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dna barcoding identifies a cosmopolitan diet in the ocean Sunfish
Scientific Reports, 2016Co-Authors: L Sousa, Raquel Xavier, Vânia Costa, Nicolas E Humphries, Clive N Trueman, Rui Rosa, David W SimsAbstract:The ocean Sunfish (Mola mola) is the world’s heaviest bony fish reaching a body mass of up to 2.3 tonnes. However, the prey M. mola consumes to fuel this prodigious growth remains poorly known. Sunfish were thought to be obligate gelatinous plankton feeders, but recent studies suggest a more generalist diet. In this study, through molecular barcoding and for the first time, the diet of Sunfish in the north-east Atlantic Ocean was characterised. Overall, DNA from the diet content of 57 individuals was successfully amplified, identifying 41 different prey items. Sunfish fed mainly on crustaceans and teleosts, with cnidarians comprising only 16% of the consumed prey. Although no adult fishes were sampled, we found evidence for an ontogenetic shift in the diet, with smaller individuals feeding mainly on small crustaceans and teleost fish, whereas the diet of larger fish included more cnidarian species. Our results confirm that smaller Sunfish feed predominantly on benthic and on coastal pelagic species, whereas larger fish depend on pelagic prey. Therefore, Sunfish is a generalist predator with a greater diversity of links in coastal food webs than previously realised. Its removal as fisheries’ bycatch may have wider reaching ecological consequences, potentially disrupting coastal trophic interactions.
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environmental influence on the seasonal movements of satellite tracked ocean Sunfish mola mola in the north east atlantic
Animal Biotelemetry, 2016Co-Authors: L Sousa, Nicolas E Humphries, David W Sims, Nuno Queiroz, Gonzalo MucientesAbstract:Determining the habitat use of mobile marine species is important for understanding responses to climate change and aids the implementation of management and conservation measures. Inference of preferred habitat use has been greatly improved by combining satellite-based oceanographic data with animal tracking techniques. Although there have been several satellite-tracking studies on ocean Sunfish Mola mola, limited information is available about either horizontal or vertical environmental preferences. In this study, both geographical movements and diving behaviour of ocean Sunfish were explored together with the environmental factors influencing this species’ space use in the north-east Atlantic. Habitat selection of electronic-tagged Sunfish (n = 22 individuals; 0.6–1.4 m total length, TL) was investigated using geolocations from Argos-linked and pop-up satellite archival transmitters. Satellite tracking (up to 171 days, mean 66 days) revealed seasonal movements: northward in spring–summer and southward in cooler months. Sunfish spent extended periods in three focal areas, the Gulf of Cadiz, north-east Iberia and the Alboran gyre, which are characterised by the presence of frontal features with elevated primary production. Habitat modelling revealed that sea surface temperature and thermal gradients significantly influenced Sunfish distribution. Diving profiles, extending from the surface to a maximum depth of 704 m, revealed different depth-use patterns not linked to geographical region or water column stratification. Overall, a size-related movement pattern was detected with larger individuals (>0.92 m TL) travelling further, exploiting greater depth ranges and spending more time at depth than smaller fish. Ocean Sunfish in the north-east Atlantic displayed seasonal movements, primarily driven by thermal preferences, extending into higher latitudes in summer. Moreover, fish also occupied productive frontal areas for long periods, presumably for improved foraging opportunities. Lastly, Sunfish showed considerable variability in diving patterns which likely reflect the tracking of planktonic prey distributions.
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The biology and ecology of the ocean Sunfish Mola mola: a review of current knowledge and future research perspectives
Reviews in Fish Biology and Fisheries, 2010Co-Authors: Edward C. Pope, David W Sims, Graeme C Hays, Tierney M Thys, Nuno Queiroz, Thomas K. Doyle, Victoria J. Hobson, Lukas Kubicek, Jonathan D. R. HoughtonAbstract:Relatively little is known about the biology and ecology of the world’s largest (heaviest) bony fish, the ocean Sunfish Mola mola , despite its worldwide occurrence in temperate and tropical seas. Studies are now emerging that require many common perceptions about Sunfish behaviour and ecology to be re-examined. Indeed, the long-held view that ocean Sunfish are an inactive, passively drifting species seems to be entirely misplaced. Technological advances in marine telemetry are revealing distinct behavioural patterns and protracted seasonal movements. Extensive forays by ocean Sunfish into the deep ocean have been documented and broad-scale surveys, together with molecular and laboratory based techniques, are addressing the connectivity and trophic role of these animals. These emerging molecular and movement studies suggest that local distinct populations may be prone to depletion through bycatch in commercial fisheries. Rising interest in ocean Sunfish, highlighted by the increase in recent publications, warrants a thorough review of the biology and ecology of this species. Here we review the taxonomy, morphology, geography, diet, locomotion, vision, movements, foraging ecology, reproduction and species interactions of M. mola . We present a summary of current conservation issues and suggest methods for addressing fundamental gaps in our knowledge.
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satellite tracking of the world s largest bony fish the ocean Sunfish mola mola l in the north east atlantic
Journal of Experimental Marine Biology and Ecology, 2009Co-Authors: David W Sims, Nuno Queiroz, Thomas K. Doyle, Jonathan D. R. Houghton, Graeme C HaysAbstract:Abstract Satellite-linked archival transmitters were used to record the movements of three ocean Sunfish (Mola mola) in the North East Atlantic. Patterns of depth use and temperature experienced by individual fish were integrated into 4-hour intervals throughout the tracking period and relayed via the Argos system. Data were recorded for 42, 90 and 54 days respectively from the three fish. The first two were tagged off southern Portugal at the end of February 2007 and travelled principally northward, while the third fish was tagged off west Ireland in August 2007 and travelled southward. These patterns are consistent with seasonal migration of ocean Sunfish to high latitudes and their subsequent return south. Maximum depths recorded by the three fish were 432 m, 472 m and 320 m respectively. All three individuals showed a diel pattern in depth use, occurring deeper during the day and shallower at night, a pattern consistent with Sunfish tracking normally vertically migrating prey. Sunfish sometimes remained continuously at deeper (> 200 m) depths during the day, but at other times they showed extensive movement through the water column typically travelling between their maximum depth and the surface within each 4-h period. The overall pattern to emerge was that ocean Sunfish travel extensively in both horizontal and vertical dimensions, presumably in search of their patchily-distributed jellyfish prey.
