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Richard W Brill - One of the best experts on this subject based on the ideXlab platform.
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temperature sensitivity of cardiac function in pelagic fishes with different vertical mobilities yellowfin Tuna thunnus albacares bigeye Tuna thunnus obesus mahimahi coryphaena hippurus and swordfish xiphias gladius
Physiological and Biochemical Zoology, 2009Co-Authors: Gina L J Galli, Holly A Shiels, Richard W BrillAbstract:Abstract We measured the temperature sensitivity, adrenergic sensitivity, and dependence on sarcoplasmic reticulum (SR) Ca2+ of ventricular muscle from pelagic fishes with different vertical mobility patterns: bigeye Tuna (Thunnus obesus), yellowfin Tuna (Thunnus albacares), and mahimahi (Coryphaena hippurus) and a single specimen from swordfish (Xiphias gladius). Ventricular muscle from the bigeye Tuna and mahimahi exhibited a biphasic response to an acute decrease in temperature (from 26° to 7°C); twitch force and kinetic parameters initially increased and then declined. The magnitude of this response was larger in the bigeye Tuna than in the mahimahi. Under steady state conditions at 26°C, inhibition of SR Ca2+ release and reuptake with ryanodine and thapsigargin decreased twitch force and kinetic parameters, respectively, in the bigeye Tuna only. However, the initial inotropy associated with decreasing temperature was abolished by SR inhibition in both the bigeye Tuna and the mahimahi. Application of ...
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Effects of open- and closed-system temperature changes on blood O_2-binding characteristics of Atlantic bluefin Tuna (Thunnus thynnus)
Fish Physiology and Biochemistry, 2006Co-Authors: Richard W Brill, P. G. BushnellAbstract:We investigated the effects of open- and closed-system temperature changes on the O_2 affinity of Atlantic bluefin Tuna ( Thunnus thynnus ) blood using in vitro methods essentially identical to those previously employed on tropical Tuna species. Bluefin Tuna blood has a general O_2 affinity ( P _50 = 2.6–3.1 kPa or 19–23 mm Hg at 0.5% CO_2) similar to that of skipjack Tuna, yellowfin Tuna, and kawakawa blood ( P _50 = 2.8–3.1 kPa at 0.5% CO_2) but significantly above that of bigeye Tuna blood ( P _50 = 1.6–2.0 kPa at 0.5% CO_2). We therefore hypothesize that bluefin Tuna are less tolerant of hypoxia than bigeye Tuna. Further, we found the P _50 of bluefin Tuna blood to be slightly reduced by a 10°C open-system temperature increase (e.g., from 4.83 kPa at 15°C to 3.95 kPa at 25°C) and to be completely unaffected by a 10°C closed-system temperature change. Bluefin Tuna blood, therefore, had a significantly reduced Bohr effect when subjected to the inevitable changes in P CO _2 and plasma pH that accompany closed-system temperature shifts (0.04–0.09 Δlog P_50ΔpH^−1) compared with the effects of changes in plasma pH accomplished by changing P CO _2 alone (0.81–0.94 Δlog P_50 Δ pH^−1). This response is similar to that of skipjack Tuna blood, but different from yellowfin or bigeye Tuna blood. During closed-system temperature changes at oxygen levels above P _50, however, bluefin Tuna blood showed a reversed temperature effect (i.e., P O _2 decreased in response to an increase in temperature). Unlike in other Tuna species, temperature effects on O_2 affinity of bluefin Tuna whole blood were similar to those previously reported for hemoglobin solutions, suggesting that red cell-mediated ligand changes are not involved.
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blood oxygen binding characteristics of bigeye Tuna thunnus obesus a high energy demand teleost that is tolerant of low ambient oxygen
Marine Biology, 2000Co-Authors: T. E. Lowe, Richard W Brill, K L CousinsAbstract:We found blood from bigeye Tuna (Thunnus obesus) to have a significantly higher O2 affinity than blood from other Tunas. Its P50 (partial pressure of oxygen, PO2 required to reach 50% saturation) was 1.6 to 2.0 kPa (12 to 15 mmHg) when equilibrated with 0.5% CO2. Previous studies employing similar methodologies found blood from yellowfin Tuna (T. albacares), skipjack Tuna (Katsuwonus pelamis), and kawakawa (Euthynnus affinis) to have a P50 of 2.8 to 3.1 kPa (21 to 23 mmHg). These observations suggest that bigeye Tuna are more tolerant of low ambient oxygen than other Tuna species, and support similar conclusions derived from laboratory whole-animal studies, depth-of-capture data, and directly-recorded vertical movements of fish in the open ocean. We also found the O2 affinity of bigeye Tuna blood to be essentially unaffected by a 10 C° open-system temperature change (as is the blood of all Tuna species studied to date). The O2 affinity of bigeye Tuna blood was, however, more affected by a 10 C° closed-system temperature change than the blood of any Tuna species yet examined. In other words, bigeye Tuna blood displayed a significantly enhanced Bohr effect (change in log P50 per unit change in plasma pH at P50) when subjected to the inevitable changes in partial pressure of carbon dioxide (PCO2) and plasma pH that accompany closed-system temperature shifts, than when subjected to changes in plasma pH accomplished by changing PCO2 alone. In vivo, the resultant large decrease in O2 affinity (i.e. the increase in P50) that occurs as the blood of bigeye Tuna is warmed during its passage through the vascular counter-current heat exchangers ensures adequate rates of O2 off-loading in the swimming muscles of this high-energy-demand teleost.
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Cardiac physiology in Tunas. I. In vitro perfused heart preparations from yellowfin and skipjack Tunas
Canadian Journal of Zoology, 1992Co-Authors: Anthony P. Farrell, Peter S. Davie, Craig E. Franklin, J. A. Johansen, Richard W BrillAbstract:An in situ heart preparation perfused with oxygenated saline was used to examine cardiac performance at 25 °C in yellowfin Tuna (Thunnus albacares) and skipjack Tuna (Katsuwonus pelamis). Heart rates (91–172 bpm in skipjack Tuna and 101–157 bpm in yellowfin Tuna) were comparable to those measured in vivo, and physiological stroke volumes were possible in yellowfin Tuna with subambient filling pressures. In yellowfin Tuna, maximum stroke volume and cardiac output were similar to the values obtained in vivo with spinally blocked animals; mean output pressures (up to 145 cmH2O, 1 cmH2O = 0.098 kPa) could exceed in vivo values without a major decrease in the resting cardiac output (homeometric regulation). In contrast, saline-perfused skipjack Tuna hearts could not develop physiological output pressures without compromising cardiac output, with cardiac output being only 63% of the in vivo value at an output pressure near the in vivo ventral aortic pressure. The poor performance of the skipjack Tuna heart is a...
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cardiorespiratory responses of skipjack Tuna katsuwonus pelamis yellowfin Tuna thunnus albacares and bigeye Tuna thunnus obesus to acute reductions of ambient oxygen
Canadian Journal of Zoology, 1990Co-Authors: P. G. Bushnell, Richard W Brill, Robert E BourkeAbstract:Cardiorespiratory responses to acute reductions of ambient oxygen were measured in skipjack Tuna (Katsuwonus pelamis), yellowfin Tuna (Thunnus albacares), and bigeye Tuna (Thunnus obesus). Prevente...
M J Williams - One of the best experts on this subject based on the ideXlab platform.
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a cost comparison of medical management and transurethral needle ablation for treatment of benign prostatic hyperplasia during a 5 year period
The Journal of Urology, 2005Co-Authors: Michael J Naslund, A. M. Carlson, M J WilliamsAbstract:ABSTRACT Purpose: We performed an analysis comparing the cost of medical management with Tuna® therapy for a 5-year period. Materials and Methods: Published costs for tamsulosin, finasteride, transurethral needle ablation (Tuna®, Medtronic, Inc., Minneapolis, Minnesota) and transurethral resection of the prostate were used to construct a cost analysis model comparing medication with Tuna. The model analyzed monotherapy with an α-blocker (tamsulosin) and a 5α-reductase inhibitor (finasteride), combination therapy using both medications, and a mixed scenario using monotherapy and combination therapy. Published data were used to estimate the rate of surgical intervention in patients initially treated with medications or Tuna. Results: Tamsulosin monotherapy was less expensive than Tuna for 5 years ($3,485 for tamsulosin vs $4,811 for Tuna year 5). Finasteride monotherapy reaches a break-even point with Tuna during year 5 ($4,867 for finasteride vs $4,811 for Tuna). Combination therapy reaches a break-even point with Tuna after approximately 2 years 7 months of treatment ($4,515 for combination therapy vs $4,572 for Tuna) and the mixed scenario breaks even with Tuna at approximately year 4 ($4,696 for medical management vs $4,645 for Tuna). Conclusions: The Tuna procedure compares favorably to combination medical therapy for the treatment of benign prostatic hyperplasia on a cost basis. α-Blocker monotherapy is less costly than Tuna while 5α-reductase inhibitor monotherapy is approximately equivalent to Tuna for 5 years. The Tuna procedure is less expensive than combination medical management for 5 years, with a break-even point at approximately 2 years 7 months.
Shane P Griffiths - One of the best experts on this subject based on the ideXlab platform.
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Longtail Tuna, Thunnus tonggol (Bleeker, 1851): a global review of population dynamics, ecology, fisheries, and considerations for future conservation and management
Reviews in Fish Biology and Fisheries, 2020Co-Authors: Shane P Griffiths, Duncan Leadbitter, Demian Willette, Farhad Kaymaram, Mohammed MoazzamAbstract:Longtail Tuna ( Thunnus tonggol ) is a neritic species that supports commercial, artisanal and recreational fisheries throughout the Indo-Pacific region. Historically receiving little attention by commercial fisheries, the global annual catch of longtail Tuna has steadily risen from around 30,000 t in the early 1980s to exceeding 200,000 t since 2004, reaching a peak of 291,264 t in 2007, and was 281,613 t in 2017. Catches of longtail Tuna in the Indian Ocean now exceed catches of principal commercial target species, such as albacore and bigeye Tunas. A sequence of stock assessments undertaken throughout the species’ range since the late 1980s persistently indicated that at least three of the four stocks defined in this paper are likely to have been, and most likely are currently, subject to overfishing and overfished as a result of excess fishing effort on this relatively slow-growing and long-lived Tuna species. As the spawning biomass of principal Tuna target species continue to decline in both the Indian and western and central Pacific Oceans, the increasing catches of longtail Tuna, other neritic Tunas, and seerfishes is worrisome. Few conservation and management measures (CMMs) are currently in place specifically for longtail Tuna, although in recent years some coastal States, Regional Fishery Bodies, and Tuna Regional Fisheries Management Organisations have begun to develop initiatives to improve the catch and biological data quality for longtail Tuna and sympatric species of neritic Tunas and Tuna-like species. This paper provides a global review of biological, ecological and fishery information to provide researchers, fishery managers and policy makers with the most current information from which to begin to guide future stock assessment and the development of CMMs for longtail Tuna.
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temporal and size related variation in the diet consumption rate and daily ration of mackerel Tuna euthynnus affinis in neritic waters of eastern australia
Ices Journal of Marine Science, 2009Co-Authors: Shane P Griffiths, Petra M Kuhnert, Fiona J MansonAbstract:Griffiths, S. P., Kuhnert, P. M., Fry, G. F., and Manson, F. J. 2009. Temporal and size-related variation in the diet, consumption rate, and daily ration of mackerel Tuna (Euthynnus affinis) in neritic waters of eastern Australia. - ICES Journal of Marine Science, 66: 720-733.The diet, food consumption, and ration of mackerel Tuna (Euthynnus affinis) were studied in Australian neritic waters. Overall, 43 prey taxa were identified from 271 stomachs. The diet was primarily pelagic clupeoids (78% by wet weight, WW; 71% by frequency of occurrence, FO) and demersal fish (19% WW; 32% FO). Multivariate regression tree analysis revealed that temporal differences, followed by fish size, explained most of the variation in the diet composition. Autumn diets differed from those in other seasons because Tuna ate virtually only engraulids then. During other seasons, engraulids were still the dominant taxon in the diet, but fish also consumed a greater variety of other prey. Small Tuna seemed to target small pelagic crustaceans and teleosts, and medium and large Tuna to consume larger pelagic and demersal teleosts. Prey consumption increased with Tuna size from 26.42 to 108.03 g d −1 for small and large Tuna, respectively. Conversely, daily ration decreased with increasing Tuna size from 4.10 to 1.95% body weight per day for medium and large Tuna, respectively. Mackerel Tuna consumed an estimated 25 036 t year −1 in the study region (170 990 km 2 ). Diet studies are becoming increasingly important in informing ecosystem models, and this study confirmed the need for sampling regimes to capture temporal and size-related variation in diet composition, to maximize the utility of data for use in such models.
Fiona J Manson - One of the best experts on this subject based on the ideXlab platform.
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temporal and size related variation in the diet consumption rate and daily ration of mackerel Tuna euthynnus affinis in neritic waters of eastern australia
Ices Journal of Marine Science, 2009Co-Authors: Shane P Griffiths, Petra M Kuhnert, Fiona J MansonAbstract:Griffiths, S. P., Kuhnert, P. M., Fry, G. F., and Manson, F. J. 2009. Temporal and size-related variation in the diet, consumption rate, and daily ration of mackerel Tuna (Euthynnus affinis) in neritic waters of eastern Australia. - ICES Journal of Marine Science, 66: 720-733.The diet, food consumption, and ration of mackerel Tuna (Euthynnus affinis) were studied in Australian neritic waters. Overall, 43 prey taxa were identified from 271 stomachs. The diet was primarily pelagic clupeoids (78% by wet weight, WW; 71% by frequency of occurrence, FO) and demersal fish (19% WW; 32% FO). Multivariate regression tree analysis revealed that temporal differences, followed by fish size, explained most of the variation in the diet composition. Autumn diets differed from those in other seasons because Tuna ate virtually only engraulids then. During other seasons, engraulids were still the dominant taxon in the diet, but fish also consumed a greater variety of other prey. Small Tuna seemed to target small pelagic crustaceans and teleosts, and medium and large Tuna to consume larger pelagic and demersal teleosts. Prey consumption increased with Tuna size from 26.42 to 108.03 g d −1 for small and large Tuna, respectively. Conversely, daily ration decreased with increasing Tuna size from 4.10 to 1.95% body weight per day for medium and large Tuna, respectively. Mackerel Tuna consumed an estimated 25 036 t year −1 in the study region (170 990 km 2 ). Diet studies are becoming increasingly important in informing ecosystem models, and this study confirmed the need for sampling regimes to capture temporal and size-related variation in diet composition, to maximize the utility of data for use in such models.
Thierry Grard - One of the best experts on this subject based on the ideXlab platform.
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development of a qpcr method for the identification and quantification of two closely related Tuna species bigeye Tuna thunnus obesus and yellowfin Tuna thunnus albacares in canned Tuna
Journal of Agricultural and Food Chemistry, 2017Co-Authors: Daline Bojolly, Perine Doyen, Urania Christaki, Veronique Verrezbagnis, Thierry GrardAbstract:Bigeye Tuna (Thunnus obesus) and yellowfin Tuna (Thunnus albacares) are among the most widely used Tuna species for canning purposes. Not only substitution but also mixing of Tuna species is prohibited by the European regulation for canned Tuna products. However, as juveniles of bigeye and yellowfin Tunas are very difficult to distinguish, unintentional substitutions may occur during the canning process. In this study, two mitochondrial markers from NADH dehydrogenase subunit 2 and cytochrome c oxidase subunit II genes were used to identify bigeye Tuna and yellowfin Tuna, respectively, utilizing TaqMan qPCR methodology. Two different qPCR-based methods were developed to quantify the percentage of flesh of each species used for can processing. The first one was based on absolute quantification using standard curves realized with these two markers; the second one was founded on relative quantification with the universal 12S rRNA gene as the endogenous gene. On the basis of our results, we conclude that our ...
