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Tuna Regional Fishery Management Organizations (tRFMOs) are increasingly interested in spatiotemporal management as a tool to reduce interaction rates with vulnerable species. We use blue shark (Prionace glauca) as a case study to demonstrate the critical first steps in the implementation process, highlighting how predictions of global habitat for vulnerable life stages can be transformed into a publicly-accessible spatial bycatch mitigation tool. By providing examples of possible management goals and an associated threshold to identify essential habitats, we show how these key areas can represent a relatively low percentage of oceanic area on a monthly basis (16–24% between 50°S and 60°N), yet can have relatively high potential protection efficiency (∼ 42%) for vulnerable stages if fishing effort is redistributed elsewhere. While spatiotemporal management has demonstrable potential for blue sharks to effectively mitigate fishing mortality on sensitive life stages, we identify inherent challenges and sequential steps that require careful consideration by tRFMOs as work proceeds. We also discuss how our single-species framework could be easily extended to a multispecies approach by assigning relative conservation risk before layering habitat model predictions in an integrated analysis. Such broader application of our approach could address the goals of tRFMOs related to reducing the ecosystem effects of fishing and pave the way for efficient fisheries co-management using an ecosystem-based approach. [ABSTRACT FROM AUTHOR]

During the 2010 Deepwater Horizon incident, the continuous release of crude oil from the damaged Macondo 252 wellhead on the ocean floor contaminated surface water habitats for pelagic fish for more than 12 weeks. The spill occurred across pelagic, neritic and benthic waters, impacting a variety of ecosystems. Chemical components of crude oil are known to disrupt cardiac function in juvenile fish, and here we investigate the effects of oil on the routine metabolic rate of chub mackerel, Scomber japonicus . Mackerel were exposed to artificially weathered Macondo 252 crude oil, prepared as a Water Accommodated Fraction (WAF), for 72 or 96 h. Routine metabolic rates were determined pre- and post-exposure using an intermittent-flow, swim tunnel respirometer. Routine energetic demand increased in all mackerels in response to crude oil and reached statistical significance relative to unexposed controls at 96 h. Chemical analyses of bile from exposed fish revealed elevated levels of fluorescent metabolites, confirming the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in the exposure WAF. The observed increase in metabolic demand is likely attributable to the bioenergetic costs of contaminant detoxification. These results indicate that short-term exposure (i.e. days) to oil has sub-lethal toxicity to mackerel and results in physiological stress during the active spill phase of the incident. [ABSTRACT FROM AUTHOR]

Abstract: Bluefin tuna (Thunnus spp.) are recently evolved teleosts with exceptional physiological and morphological specializations, whose aquaculture has become an increasing sector of the bluefin fishery. We studied the molecular expression of target gene transcripts in respect to experimental chronic cold and warm exposure in Pacific bluefin tuna liver, spleen, kidney and gill. The genes of interest were chosen as representative “biomarkers”, shown to change in fish exposed to temperature challenges: chaperon molecules (Hsp70); proteins engaged in active transport (Na+/K+ ATP-ase); oxygen-dependent genes (HIF-1α); and cytokines (IL-1β, TNF-α). In captive Pacific bluefin tuna, these genes showed constitutive expression in all organs examined. A seven-week chronic exposure to cold temperature resulted in shifts in expression levels of oxygen-dependent HIF transcripts in spleen and gill, and Hsp70 in spleen, while other gene transcripts remain unaffected. The results indicate that a long-term exposure to cold imposes physiological pressure on this endothermic fish species, especially on haemaotopoietic and gas-exchange organs. We suggest that these two genes can be considered as potential biomarkers for thermal shifts in captive bluefin. [Copyright &y& Elsevier]

Tagging of Pacific pelagics (TOPP) is a pilot program of the Census of marine life (CoML) that will lead to understanding of pelagic habitat use by marine vertebrates and large squid in the North Pacific. Taking a multispecies approach, the TOPP project will use a range of electronic tag technologies to put the distribution and behavior of pelagic organisms in the context of the oceanography of the North Pacific. Tag-bearing animals will be used as autonomous ocean profilers to enhance sparse oceanographic observations for vast ocean regions. These autonomous ocean samplers will provide unprecedented coverage of the water column structure of the North Pacific. The temporal and spatial data generated by this project will provide an “organism-eye” view of several interactive oceanic regimes in the North Pacific. Twenty target species, including tunas, sharks, pinnipeds, cetaceans, seabirds, and marine turtles, will be monitored with electronic tags. Animal-collected oceanic data will be assimilated into global ocean databases, complement traditional methodologies and be used to help validate nearshore, regional, and basin scale ocean models. As more environmental information is gathered and delivered from the tagged animals, new insights will be obtained about their individual behaviors, as well as how diverse species have separately evolved to forage, reproduce, and survive in the vast pelagic environment. This multi-disciplinary approach will allow a novel merger of biological and physical data to provide a new understanding of the relationship between the movements and behaviors of marine organisms and oceanographic processes in the eastern North Pacific. [Copyright &y& Elsevier]

A numerical model which simulates the adsorption of radionuclides by migrating bluefin tuna in the Mediterranean Sea is described, in order to determine the level of contamination of these fish after a hypothetical nuclear accident and thus be able to assess the possible impact on human consumption. A 4–species foodweb model is incorporated into a Lagrangian model describing physical transport (advection, mixing, radioactive decay and interactions of radionuclides with sediments). Tuna is the last trophic level in the foodweb model and the equation providing the temporal evolution of radionuclide concentration in its flesh is solved along the fish trajectories, which were obtained through electronic tagging of fishes. The model was applied to the western Mediterranean, where several worst–case hypothetical accidents were simulated, both from a coastal nuclear power plant and from a vessel. Resulting 137Cs concentrations in migrating tuna were similar, or slightly higher, than reported background concentrations in these fishes and well below established safety levels. Maximum calculated concentrations in tuna flesh is in the order of 1 Bq/kg (wet weight). This is due to the rapid movement of the fishes, which spend only limited time over the most contaminated spots. • Marine Lagrangian radionuclide transport model developed for the western Mediterranean Sea • A foodweb model included within it, bluefin tuna is the highest trophic level • Tuna model equations solved along tuna tracks, obtained through electronic tagging of fishes • Accidents simulated in a coastal nuclear power plant and nuclear submarine • Wild tuna would not be significantly affected by a nuclear accident in the western Mediterranean • The tool can be applied to other marine regions and species of interest [ABSTRACT FROM AUTHOR]

Ecological data are being opportunistically synthesised at unprecedented scales in response to the global biodiversity and climate crises. Such syntheses are often only possible through large-scale, international, multidisciplinary collaborations and provide important pathways for addressing urgent conservation questions. Although large collaborative data syntheses can lead to high-impact successes, they can also be plagued with difficulties. Challenges include the standardisation of data originally collected for different purposes, integration and interpretation of knowledge sourced across different disciplines and spatio-temporal scales, and management of differing perspectives from contributors with distinct academic and cultural backgrounds. Here, we use the collective expertise of a global team of conservation ecologists and practitioners to highlight common benefits and hurdles that arise with the development of opportunistic collaborative syntheses. We outline a framework of "best practice" for developing such collaborations, encompassing the design, implementation, and deliverable phases. Our framework addresses common challenges, highlighting key actions for successful collaboration and emphasizing the support requirements. We identify funding as a major constraint to sustaining the large, international, multidisciplinary teams required to advance collaborative syntheses in a just, equitable, diverse, and inclusive way. We further advocate for thinking strategically from the outset and highlight the need for reshaping funding agendas to prioritize the structures required to propel global scientific networks. Our framework will advance the science needed for ecological conservation and the sustainable use of global natural resources by supporting proto-groups initiating new syntheses, leaders and participants of ongoing projects, and funders who want to facilitate such collaborations in the future. • Increasingly complex global environmental challenges call for speed up research. • Large collaborative data syntheses lead to high-impact successes. • Bottom-up, opportunistic collaborative syntheses can address global wicked problems. • Despite their value, opportunistic syntheses are plagued with challenges. • We provide a framework for 'best practice' of such collaborative projects. [ABSTRACT FROM AUTHOR]

Abstract: The thermal sensitivity of metabolic performance in vertebrates requires a better understanding of the temperature sensitivity of cardiac function. The cardiac sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2) is vital for excitation–contraction (E–C) coupling and intracellular Ca2+ homeostasis in heart cells. To better understand the thermal dependency of cardiac output in vertebrates, we present comparative analyses of the thermal kinetics properties of SERCA2 from ectothermic and endothermic vertebrates. We directly compare SR ventricular microsomal preparations using similar experimental conditions from sarcoplasmic reticulum isolated from cardiac tissues of mammals and fish. The experiments were designed to delineate the thermal sensitivity of SERCA2 and its role in thermal sensitivity Ca2+ uptake and E–C coupling. Ca2+ transport in the microsomal SR fractions from rabbit and bigeye tuna (Thunnus obesus) ventricles were temperature dependent. In contrast, ventricular SR preparations from coho salmon (Onchorhychus kisutch) were less temperature dependent and cold tolerant, displaying Ca2+ uptake as low as 5°C. As a consequence, the Q 10 values in coho salmon were low over a range of different temperature intervals. Maximal Ca2+ transport activity for each species occurred in a different temperature range, indicating species-specific thermal preferences for SERCA2 activity. The mammalian enzyme displayed maximal Ca2+ uptake activity at 35°C, whereas the fish (tuna and salmon) had maximal activity at 30°C. At 35°C, the rate of Ca2+ uptake catalyzed by the bigeye tuna SERCA2 decreased, but not the rate of ATP hydrolysis. In contrast, the salmon SERCA2 enzyme lost its activity at 35°C, and ATP hydrolysis was also impaired. We hypothesize that SERCA2 catalysis is optimized for species-specific temperatures experienced in natural habitats and that cardiac aerobic scope is limited when excitation–contraction coupling is impaired at low or high temperatures due to loss of SERCA2 enzymatic function. [Copyright &y& Elsevier]

Abstract: The movements, behavior, and habitat utilization of yellowfin tuna, Thunnus albacares, in the eastern Pacific Ocean off Baja California, Mexico, are described from analyses of 31,357 days of day-log and 28,835 days of time-series data, downloaded from 126 archival tags recovered from yellowfin (57–162cm in length and 1.2–5.2 years of age) at liberty from 90 to 1161 d (), collected during 2002–2010. An unscented Kalman filter model with sea-surface temperature measurements integrated (UKFsst) was used to process the archival tag data sets in order to obtain improved estimates of geographic positions and most probable tracks (MPTs) and parameters. The median parameter estimates from the UKFsst model for errors in longitude (σ x ) and latitude (σ y ) were 0.32° and 1.36°, respectively, for directed movements (u and v) were 0.27 and 0.77nm/d, respectively, and for dispersive movement (D) was 144.3nm2/d. The MPTs for 120 (95%) of the yellowfin remained within 1358km of their release locations, indicating restricted horizontal utilization distributions, and fidelity to this area of high biological productivity. There are observed differences in the movement patterns and parameters for fish released in different areas. Analyses of daily timed depth and temperature records resulted in the classification of the data into four distinct behaviors. When exhibiting type-1 diving behavior (82.9% of all days at liberty) the fish remained at depths of less than 50m at night and did not dive to depths greater than about 100m during the day. Type-2 diving behavior (17.1% of all days at liberty) was characterized by 10 or more dives in excess of 150m during the day. Spatial and temporal patterns are evident in the distributions of type-1 and type-2 diving behaviors. Surface-oriented behavior, defined as the time fish remained at depths less than 10m for more than 10min, was also evaluated. The mean number and duration of daytime surface-oriented events per day, for all fish, were 7.6 and 24.2min, respectively. There are significant differences among ages in the percentages of days classified as type-1 and type-2 behaviors, durations of those events, and in the numbers and durations of surface-oriented events. Yellowfin tuna exhibited occasional deep-diving behavior, and some dives were to depths exceeding 1000m, where ambient temperatures were less than 5°C. There are significant differences among ages in the nighttime and daytime average depths. The differences are the result of the fish of ages greater than 3 years showing greater daytime average depths and lesser nighttime average depths. [Copyright &y& Elsevier]

• Large Atlantic bluefin tuna tagged off the coast of Ireland utilize the warm North Atlantic Current to access foraging areas in the North Atlantic Ocean. • Five hotspots of Atlantic bluefin tuna occur in the central and eastern North Atlantic Ocean. Each are in regions with long-lived, quasi-stationary anticyclonic features (i.e., eddies or recirculation). • Daily maximum depth and time at mesopelagic depths (i.e., greater than 200 m) are positively correlated with absolute dynamic topography in the open ocean. • In the Winter, a majority of Atlantic bluefin tuna tagged in Irish waters travel to the Newfoundland Basin, a region with intense mesoscale eddy activity and high mesopelagic fish biomass. • Some Atlantic bluefin tuna migrated in the Spring to the Mediterranean Sea, an important spawning ground for this species. Electronic tagging of Atlantic bluefin tuna (ABT; Thunnus thynnus) has shaped our understanding of their movements and migrations throughout the Atlantic basin. In this study, we used pop-up satellite archival tagging data to examine the movements of 51 large (CFL µ ± σ: 215 ± 15 cm) ABT tagged off the coast of Ireland. When combined with satellite oceanographic data, we found that ABT take advantage of the warm North Atlantic Current to access foraging areas in the North Atlantic Ocean. We identified four potential foraging regions: (1) off the coast of Ireland, (2) the Bay of Biscay, (3) the Newfoundland Basin, and (4) the West European Basin. In addition, 14 ABT migrated to their spawning grounds in the Mediterranean Sea, entering by May 16 and exiting by July 7, on average. In all five regions, anticyclonic ocean features (i.e., eddies or recirculation) were present. In the open ocean, these features often co-occurred with areas where the daily maximum depth of tuna exceeded 400 m and tuna spent extended time at mesopelagic depths (i.e., greater than 200 m). We hypothesize that ABT exploit anticyclonic structures to forage on the abundant mesopelagic fish communities. Additionally, our results suggest that ABT are travelling across the North Atlantic Ocean in a directed migration to the Newfoundland Basin to reach what may be one of the best mesopelagic feeding grounds in the world. [ABSTRACT FROM AUTHOR]

Abstract Bluefin tunas are highly specialized fish with unique hydrodynamic designs and physiological traits. In this study, we present results in a captive population that demonstrate strong effects of ambient temperature on the tail beat frequency and swimming speed of a pelagic fish in both pre- and post-prandial states. We measured the responses of a ram ventilator, the Pacific bluefin tuna (Thunnus orientalis), after digestion of a meal to explore the impacts of the metabolic costs of digestion on behavior and respiration. A combination of respirometry, physiological biologging of visceral temperatures, and activity monitoring with accelerometry were used to explore the metabolic costs of digestion and the impacts on ventilation and swimming speed. Experiments were conducted at temperatures that are within the metabolic optimum for Pacific bluefin tuna (17 °C), and at a second temperature corresponding to the upper distributional limit of the species in the California Current (24 °C). Warmer temperatures resulted in higher tail-beat frequency and greater elevation of body temperature in pre-prandial Pacific bluefin tuna. Specific dynamic action (SDA) events resulted in a significant postprandial increase in tail-beat frequency of ~0.2 Hz, compared to pre-prandial levels of 1.5 Hz (17 °C) and 1.75 Hz (24 °C), possibly resulting from ventilatory requirements. Data of fish exercised in a swim-tunnel respirometer suggest that the observed increase in tail-beat frequency comprise 5.5 and 6.8% of the oxygen demand during peak SDA at 24 °C and 17 °C respectively. The facultative increase in swimming speed might increase oxygen uptake at the gills to meet the increasing demand by visceral organs involved in the digestive process, potentially decreasing the available energy of each meal for other metabolic processes, such as growth, maturation, and reproduction. We hypothesize that these post-prandial behaviors allow tuna to evacuate their guts more quickly, ultimately permitting fish to feed more frequently when prey is available. Highlights • Pacific bluefin tuna display temperature dependence in volitional activity. • Specific Dynamic Action (SDA) elevates volitional swimming speed. • SDA linked increases in activity only comprise minor portion of total oxygen consumption. • Temperature driven changes in activity are important considerations for bioenergetics models. [ABSTRACT FROM AUTHOR]

• Species-specific quantitative PCR assays were developed for two reef shark species. • Environmental DNA samples were taken from a remote archipelago in the Indian Ocean. • Both species were detected consistently around a highly protected atoll. • There was sporadic detection around atolls experiencing illegal fishing activity. • eDNA detection did not correlate with concurrent visual survey results or with historical telemetry hotspots. Environmental DNA (eDNA) methods are being increasingly used in proof-of-concept studies to detect shark species, many populations of which are experiencing severe declines. These methods are widely seen as the future of biodiversity monitoring, but they have yet to become established as routine monitoring techniques for elasmobranch species. Here, we developed species-specific quantitative PCR assays for the detection of grey reef shark (Carcharhinus amblyrhynchos) and silvertip shark (Carcharhinus albimarginatus). We assessed whether species-specific eDNA methods could infer the distribution of the two species around the atolls of the Chagos Archipelago, which, despite being surrounded by a large marine protected area, experience contrasting levels of illegal fishing leading to heterogeneity in shark population densities. We found that eDNA detections were significantly reduced and sporadic around the northern atolls, which are under high pressure from illegal fishing. By contrast eDNA detections of both species were ubiquitous and consistent around the highly protected atoll Diego Garcia. We postulate that current levels of illegal, unreported and unregulated (IUU) fishing is having a significant impact on the shark community in the northern atolls and suppressing local reef shark populations. In the northern atolls we also employed visual and acoustic telemetry techniques to reveal the distribution of reef sharks. We found that despite eDNA samples being taken directly after visual surveys, detection results did not correlate, suggesting a need for further optimisation of eDNA methods for detecting sharks. However, both species were detected by eDNA in sites where they were not observed, highlighting that the scale of the sampling environment must be considered when inferring eDNA results and showing that eDNA methods can be used to fill gaps in data from more established monitoring techniques. We conclude that eDNA methods should be used in combination with other techniques to provide a complete picture of shark distribution so that threatened species can be better protected. [ABSTRACT FROM AUTHOR]

Large marine protected areas (MPAs) have recently been established throughout the world at an unprecedented pace, yet the value of these reserves for mobile species conservation remains unclear. Reef shark populations continue to decline even within some of the largest MPAs, fueling unresolved debates over the ability of protected areas to aid mobile species that transit beyond MPA boundaries. We assessed the capacity of a large MPA to conserve grey reef sharks - a Near Threatened species with a widespread distribution and poorly understood offshore movement patterns - using a combination of conventional tags, satellite tags, and an emerging vessel tracking technology. We found that the 54,000 km 2 U.S. Palmyra Atoll National Wildlife Refuge in the central Pacific Ocean provides substantial protection for grey reef sharks, as two-thirds of satellite-tracked sharks remained within MPA boundaries for the entire study duration. Additionally, our analysis of > 0.5 million satellite detections of commercial fishing vessels identified virtually no fishing effort within the refuge and significant effort beyond the MPA perimeter, suggesting that large MPAs can effectively benefit reef sharks and other mobile species if properly enforced. However, our results also highlight limitations of place-based conservation as some of these reef-associated sharks moved surprising distances into pelagic waters (up to 926 km from Palmyra Atoll, 810 km beyond MPA boundaries). Small-scale fishermen operating beyond MPA boundaries (up to 366 km from Palmyra) captured 2% of sharks that were initially tagged at Palmyra, indicating that large MPAs provide substantial, though incomplete, protection for reef sharks. [ABSTRACT FROM AUTHOR]

Specific dynamic action (SDA), the increase in metabolic expenditure associated with consumption of a meal, represents a substantial portion of fish energy budgets and is highly influenced by ambient temperature. The effect of temperature on SDA has not been studied in yellowfin tuna ( Thunnus albacares , Bonnaterre 1788), an active pelagic predator that occupies temperate and subtropical waters. The energetic cost and duration of SDA were calculated by comparing routine and post-prandial oxygen consumption rates. Mean routine metabolic rates in yellowfin tuna increased with temperature, from 136 mg O 2 kg − 1 h − 1 at 20 °C to 211 mg O 2 kg − 1 h at 24 °C. The mean duration of SDA decreased from 40.2 h at 20 °C to 33.1 h at 24 °C, while mean SDA coefficient, the percentage of energy in a meal that is consumed during digestion, increased from 5.9% at 20 °C to 12.7% at 24 °C. Digestion in yellowfin tuna is faster at a higher temperature but requires additional oxidative energy. Enhanced characterization of the role of temperature in SDA of yellowfin tuna deepens our understanding of tuna physiology and can help improve management of aquaculture and fisheries. [ABSTRACT FROM AUTHOR]

Hemoglobin–oxygen (Hb–O 2 ) binding properties are central to aerobic physiology, and must be optimized for an animal's aerobic requirements and environmental conditions, both of which can vary widely with seasonal changes or acutely with diving. In the case of tunas, the matter is further complicated by large regional temperature differences between tissues within the same animal. This study investigates the effects of thermal acclimation on red blood cell Hb–O 2 binding in Pacific bluefin tuna ( T. orientalis ) and yellowfin tuna ( T. albacares ) maintained in captive tanks at acclimation temperatures of 17°, 20° and 24 °C. Oxygen binding properties of acclimated tuna isolated red blood cells were examined under varying experimental temperatures (15°–35 °C) and CO 2 levels (0%, 0.5% and 1.5%). Results for Pacific bluefin tuna produced temperature-independence at 17 °C- and 20 °C-acclimation temperatures and significant reverse temperature-dependence at 24 °C-acclimation in the absence of CO 2 , with instances of reverse temperature-dependence in 17 °C- and 24 °C-acclimations at 0.5% and 1.5% CO 2 . In contrast, yellowfin tuna produced normal temperature-dependence at each acclimation temperature at 0% CO 2 , temperature-independence at 0.5% and 1.5% CO 2 , and significant reverse temperature-dependence at 17 °C-acclimation and 0.5% CO 2 . Thermal acclimation of Pacific bluefin tuna increased O 2 binding affinity of the 17 °C-acclimation group, and produced a significantly steeper oxygen equilibrium curve slope (n H ) at 24 °C-acclimation compared to the other acclimation temperatures. We discuss the potential implications of these findings below. [ABSTRACT FROM AUTHOR]

Tuna bioenergetics can be described by the following relationship: the energy available for growth is equal to the food energy minus all metabolic costs. These costs include routine metabolic rate, specific dynamic action, increased activity level, eliminated waste, and gonadal development. Captive populations of Pacific bluefin tuna ( Thunnus orientalis ) were held at ~ 20 °C in fiberglass tanks and fed on a regular schedule with a diet formulated to achieve an energetic content of 176 ± 36 kJ · kg − 1 of biomass · day − 1 (mean ± s.d.). To conduct a bioenergetic study, growth rates during the captive period and tissue energy values post-mortem were empirically determined. Daily growth rates were obtained from a von Bertalanffy growth function based on curved fork length (CFL) measurements of live fish and post-mortem morphometrics. The parameters obtained for the captive bluefin growth function were 225.13 cm straight fork length (SFL), 0.173, and − 0.497 years for L ∞ , k , and t o , respectively. The growth equation, SFL = 225.13 · (1 − e (− 0.173(t-(− 0.497))) ) in conjunction with the length-mass regression (where body mass M = 4.98 × 10 − 6 × SFL 3.3186 ) gave a daily growth increase of 32.60 ± 2.40 g · day − 1 for Pacific bluefin tuna of 2.2 years of age and 11.4 ± 1.0 kg (the average age and mass of a fish in the study). The average tissue energy value from four sampled tuna was 7.66 ± 0.40 kJ · g − 1 , and applying the daily growth increase estimate provides a daily energy gain of 249.7 kJ, which is 12.4% of an ingested meal's total energy content. A food conversion ratio of 17.8:1 is estimated for a meal consisting solely of sardines and 22.6:1 for a mixed diet consisting of sardines, squid, and a gelatin-vitamin mixture at the stated feeding regimen. This paper presents the first data on actual food conversion ratios and bioenergetic utilization for Pacific bluefin tuna. [ABSTRACT FROM AUTHOR]

Highlights: [•] MC252 and Alaskan crude oils produced highly similar developmental toxicity in zebrafish embryos. [•] Both types of crude oil produced canonical petrogenic PAH cardiotoxicity manifested as reduced ventricular contractility. [•] Both types of crude oil produced non-cardiac effects on cranial vasculature and finfolds, including phototoxicity. [•] As for ANSCO, toxicity of MC252 oil based on units of ∑PAC was linked to the relative proportion of tricyclic PACs. [ABSTRACT FROM AUTHOR]

Abstract: In this study, 253 Pacific bluefin tuna were archivally tagged off the coast of California, USA and Baja California, Mexico between August 2002 and August 2005. One hundred and fifty-seven fish were recaptured and 143 datasets were obtained and analyzed, yielding electronic tag datasets of up to 1203days. Mean days at large for the 143 fish was 359±248 (SD) days. A total of 38,012 geolocations were calculated from light-based longitude and SST-based latitude estimates, allowing us to examine the seasonal movement of juvenile bluefin tuna off the west coast of North America. Electronic tagged bluefin tuna showed repeatable seasonal movements along the west coast of North America. Bluefin tuna were found farthest south in the spring when they were located off southern Baja California, Mexico and farthest north in the fall when fish were found predominately off central and northern California. Fish showed latitudinal movement patterns that were correlated with peaks in coastal upwelling-induced primary productivity. Interannual variation in the locality of these productivity peaks was linked with a corresponding movement in the distribution of tagged fish. Overall geographical area occupied by tagged bluefin varied with primary productivity, with fish being more tightly clustered in areas of high productivity and more dispersed in regions of low productivity. In the spring through fall, bluefin tuna were located in areas with the highest levels of primary productivity available in the California Current ecosystem. However, in the winter months, tagged bluefin tuna were found in areas with lower productivity compared to other regions along the coast at that time of year suggesting that during the winter, bluefin tuna are feeding on aggregations of pelagic red crabs, sardines and anchovies that preferentially spawn in areas of reduced coastal upwelling. [Copyright &y& Elsevier]

Abstract: We analyzed some of the primary biological and physical dynamics within the eastern Pacific leatherback turtle (Dermochelys coriacea) migration area in relation to ENSO and leatherback nesting ecology at Parque Nacional Marino Las Baulas (PNMB), Costa Rica. We used data from remote sensing to calculate resource availability via a net primary production (NPP) model, and to analyze the physical dynamics of the migration area via sea surface temperature fronts. Within the migration area, NPP north of 15°S was highly governed by interannual variability as indicated by the Multivariate ENSO Index while south of 15°S, production had a more seasonal signal. Nesting peaks of leatherbacks at PNMB were associated with cool, highly productive La Niña events and with large-scale equatorial phytoplankton blooms encompassing 110°W that were induced by iron enrichment following the termination of El Niño events. Resource availability in the northern migration area (eastern equatorial Pacific) appeared to determine the nesting response for the population at PNMB, Costa Rica. We suggest that ENSO significantly influences the nesting ecology of leatherbacks at PNMB because the majority of the population consists of pelagic foragers that strictly rely on the eastern equatorial Pacific for prey consumption prior to the nesting season. Coastal foragers may be a minority in the population because of high mortality rates associated with coastal gillnet fisheries along Central and South America. [Copyright &y& Elsevier]

Abstract: Tunas have an extraordinary physiology including elevated metabolic rates and high cardiac performance. In some species, retention of metabolic heat warms the slow oxidative swimming muscles and visceral tissues. In all tunas, the heart functions at ambient temperature. Enhanced rates of calcium transport in tuna myocytes are associated with increased expression of proteins involved in the contraction-relaxation cycle. The cardiac SR Ca2+-ATPase (SERCA2) plays a major role during cardiac excitation–contraction (E-C) coupling. Measurements of oxalate-supported Ca2+-uptake in atrial SR vesicles isolated from four species of tunas indicate that bluefin have at least two fold higher Ca2+-uptake than all other tunas examined between 5 and 30 °C. The highest atrial Ca2+-uptake was measured in bluefin tuna at 30 °C (23.32±1.58 nmol Ca2+/mg/min). Differences among tunas in the temperature dependency of Ca2+-uptake were similar for ATP hydrolysis. Western blot analysis revealed a significant increase in SERCA2 content associated with higher Ca2+ uptake rates in the atrial tissues of bluefin tuna and similar RyR expression across species. We propose that the expression of EC coupling proteins in cardiac myocytes, and the higher rates of SERCA2 activity are an important evolutionary step for the maintenance of higher heart rates and endothermy in bluefin tuna. [Copyright &y& Elsevier]

: ObjectiveIn some women, a decline in sexual interest accompanies a relative androgen insufficiency after menopause. We sought to characterize the hormonal effects of the combination of oral esterified estrogens and methyltestosterone and to investigate whether this regimen improves hypoactive sexual desire.: DesignDouble-blind randomized trial.: SettingHealthy volunteers in a multicenter research environment.: Patient(s)Postmenopausal women taking estrogen therapy who were experiencing hypoactive sexual desire.: Intervention(s)4 months of treatment with 0.625 mg of esterified estrogens (n = 111) or the combination of 0.625 mg of esterified estrogens and 1.25 mg of methyltestosterone (n = 107).: Main outcome measure(s)Baseline and end-of-study measurements of total and bioavailable testosterone and sex hormone–binding globulin (SHBG), and mean change in level of sexual interest or desire as rated on the Sexual Interest Questionnaire.: Result(s)Treatment with the combination of esterified estrogens and methyltestosterone significantly increased the concentration of bioavailable testosterone and suppressed SHBG. Scores measuring sexual interest or desire and frequency of desire increased from baseline with combination treatment and were significantly greater than those achieved with esterified estrogens alone. Treatment with the combination was well tolerated.: Conclusion(s)Increased circulating levels of unbound testosterone and suppression of SHBG provide a plausible hormonal explanation for the significantly improved sexual functioning in women receiving the combination of esterified estrogen and methyltestosterone. [Copyright &y& Elsevier]

The yellowfin tuna (Thunnus albacares) is a widely distributed, migratory species that supports valuable commercial fisheries throughout their range. Management of migratory species requires knowledge of movement, mixing and key life history parameters such as growth rate, natural and fisheries mortality. Current management is based on the assumptions that the species is highly migratory and populations are well mixed, but these assumptions have been questioned by recent studies. Since November 2015, yellowfin tuna have been tagged with conventional, archival and pop-up satellite tags (PSAT) in the South Atlantic Ocean around St Helena, with the goal of better understanding their movement patterns and ecology in this region. Conventional tags were attached to 4049 yellowfin tuna (size range 24–158 cm fork length, FL), PSAT tags were deployed on 15 yellowfin in inshore St Helena waters (size range 95–138 cm FL) and 7 yellowfin (size range 125–140 cm FL) at Cardno Seamount, and archival tags were deployed on 48 yellowfin tuna in inshore St Helena waters (size range 69–111 cm FL). Most yellowfin tuna remained within 70 km of their release location, suggesting a degree of retention to the region. Although displacement of yellowfin was generally low, the furthest distance travelled between release and recapture location was 2755 km, with other tuna also displaying large-scale movements. Tagging revealed connections between inshore regions and seamounts, as well as links between St Helena waters and key fishing regions and putative spawning grounds in the Gulf of Guinea. [ABSTRACT FROM AUTHOR]

Determining population trends is critical for evaluating management actions and prioritizing species protections. In this study, we used empirical data to produce an estimate of the population trend for sub-adult and adult white sharks in central California. We used the unique dorsal fin morphology to build a mark-recapture data set in a modified Jolly-Seber model (POPAN formulation) to estimate annual abundance and then investigate population growth rates using parametric bootstrapping methods for sub-adult and adult sharks (males and females). For all demographic groups combined, we found equivocal evidence for a positive regional population growth (λ = 1.07 (95% CI = 0.91 to 1.23)). However, sex- and size-specific population growth rate estimates provided some evidence of population increases for reproductively mature males (λ = 1.06 (95% CI = 0.99 to 1.13)) and females (λ = 1.06 (95% CI = 0.95 to 1.17)). For sub-adult male and female white sharks, point estimates of λ were positive but uncertainty prevents strong inference (λ = 1.07 (95% CI = 0.85 to 1.29)) and (λ = 1.08 (95% CI = 0.88 to 1.28)), respectively. Our findings of a potential increase in reproductive-aged white sharks in central California may be a result of regional fluxes in density or attributed in part to current protection efforts and subsequent increase in abundance of pinnipeds as well as reduced gill-net fisheries mortality of juveniles. A trend estimate for the entire northeastern Pacific will require obtaining similar data across known aggregation areas along the west coast of North America. [ABSTRACT FROM AUTHOR]