Basic Life Science Research Associate, Oceans
- Pop-up archival tags reveal environmental influences on the vertical movements of silvertip sharks Carcharhinus albimarginatus MARINE ECOLOGY PROGRESS SERIES 2023; 717: 85-105
- Seasonal and diel habitat use of blue marlin Makaira nigricans in the North Atlantic Ocean ICES JOURNAL OF MARINE SCIENCE 2023
Diving into the vertical dimension of elasmobranch movement ecology.
2022; 8 (33): eabo1754
Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements.
View details for DOI 10.1126/sciadv.abo1754
View details for PubMedID 35984887
- Global habitat loss of a highly migratory predator, the blue marlin (Makaira nigricans) DIVERSITY AND DISTRIBUTIONS 2022
- First insights into the movements and vertical habitat use of blue marlin (Makaira nigricans) in the eastern North Atlantic ANIMAL BIOTELEMETRY 2022; 10 (1)
- Shark movement strategies influence poaching risk and can guide enforcement decisions in a large, remote marine protected area JOURNAL OF APPLIED ECOLOGY 2020
- Energetic savings when switching from a whole-fish type diet to a commercial pelleted diet in California yellowtail (Seriola dorsalis) AQUACULTURE 2020; 516
- Estimating Space Use of Mobile Fishes in a Large Marine Protected Area With Methodological Considerations in Acoustic Array Design FRONTIERS IN MARINE SCIENCE 2019; 6
- Temperature dependent pre- and postprandial activity in Pacific bluefin tuna (Thunnus orientalis) COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY 2019; 231: 131–39
Direct measurement of swimming and diving kinematics of giant Atlantic bluefin tuna (Thunnus thynnus)
ROYAL SOCIETY OPEN SCIENCE
2019; 6 (5): 190203
Tunas possess a range of physiological and mechanical adaptations geared towards high-performance swimming that are of considerable interest to physiologists, ecologists and engineers. Advances in biologging have provided significant improvements in understanding tuna migrations and vertical movement patterns, yet our understanding of the locomotion and swimming mechanics of these fish under natural conditions is limited. We equipped Atlantic bluefin tuna (Thunnus thynnus) with motion-sensitive tags and video cameras to quantify the gaits and kinematics used by wild fish. Our data reveal significant variety in the locomotory kinematics of Atlantic bluefin tuna, ranging from continuous locomotion to two types of intermittent locomotion. The tuna sustained swimming speeds in excess of 1.5 m s-1 (0.6 body lengths s-1), while beating their tail at a frequency of approximately 1 Hz. While diving, some descents were entirely composed of passive glides, with slower descent rates featuring more gliding, while ascents were primarily composed of active swimming. The observed swimming behaviour of Atlantic bluefin tuna is consistent with theoretical models predicting such intermittent locomotion to result in mechanical and physiological advantages. Our results confirm that Atlantic bluefin tuna possess behavioural specializations to increase their locomotory performance, which together with their unique physiology improve their capacity to use pelagic and mesopelagic habitats.
View details for DOI 10.1098/rsos.190203
View details for Web of Science ID 000470127300046
View details for PubMedID 31218059
View details for PubMedCentralID PMC6549966
Temperature dependent pre- and postprandial activity in Pacific bluefin tuna (Thunnus orientalis).
Comparative biochemistry and physiology. Part A, Molecular & integrative physiology
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 ventilator 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.
View details for PubMedID 30735702
- Potential detection of illegal fishing by passive acoustic telemetry ANIMAL BIOTELEMETRY 2019; 7 (1)
The effect of temperature on postprandial metabolism of yellowfin tuna (Thunnus albacares)
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY
2016; 195: 32-38
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 136mgO2kg(-1)h(-1) at 20°C to 211mgO2kg(-1)h at 24°C. The mean duration of SDA decreased from 40.2h at 20°C to 33.1h 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.
View details for DOI 10.1016/j.cbpa.2016.01.005
View details for Web of Science ID 000373410500005
View details for PubMedID 26794613
Exposure to Deepwater Horizon weathered crude oil increases routine metabolic demand in chub mackerel, Scomber japonicus.
Marine pollution bulletin
2015; 98 (1-2): 259-266
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 12weeks. 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 96h. 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 96h. 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.
View details for DOI 10.1016/j.marpolbul.2015.06.039
View details for PubMedID 26210587
Hearing thresholds of swimming Pacific bluefin tuna Thunnus orientalis
JOURNAL OF COMPARATIVE PHYSIOLOGY A-NEUROETHOLOGY SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY
2015; 201 (5): 441-454
Pacific bluefin tuna (Thunnus orientalis) is a highly migratory, commercially valuable species potentially vulnerable to acoustic noise generated from human activities which could impact behavior and fitness. Although significant efforts have been made to understand hearing abilities of fishes, the large size and need to continuously swim for respiration have hindered investigations with tuna and other large pelagic species. In this study, Pacific bluefin tuna were trained to respond to a pure tone sound stimulus ranging 325-800 Hz and their hearing abilities quantified using a staircase psychophysical technique. Hearing was most sensitive from 400 to 500 Hz in terms of particle motion (radial acceleration -88 dB re 1 m s(-2); vertical acceleration -86 dB re 1 m s(-2)) and sound pressure (83 dB re 1 μPa). Compared to yellowfin tuna (Thunnus albacares) and kawakawa (Euthynnus affinis), Pacific bluefin tuna has a similar bandwidth of hearing and best frequency, but greater sensitivity overall. Careful calibration of the sound stimulus and experimental tank environment, as well as the adoption of behavioral methodology, demonstrates an experimental approach highly effective for the study of large fish species in the laboratory.
View details for DOI 10.1007/s00359-015-0991-x
View details for Web of Science ID 000353353700002
View details for PubMedID 25732931
Growth and Maximum Size of Tiger Sharks (Galeocerdo cuvier) in Hawaii
2014; 9 (1)
Tiger sharks (Galecerdo cuvier) are apex predators characterized by their broad diet, large size and rapid growth. Tiger shark maximum size is typically between 380 & 450 cm Total Length (TL), with a few individuals reaching 550 cm TL, but the maximum size of tiger sharks in Hawaii waters remains uncertain. A previous study suggested tiger sharks grow rather slowly in Hawaii compared to other regions, but this may have been an artifact of the method used to estimate growth (unvalidated vertebral ring counts) compounded by small sample size and narrow size range. Since 1993, the University of Hawaii has conducted a research program aimed at elucidating tiger shark biology, and to date 420 tiger sharks have been tagged and 50 recaptured. All recaptures were from Hawaii except a single shark recaptured off Isla Jacques Cousteau (24°13'17″N 109°52'14″W), in the southern Gulf of California (minimum distance between tag and recapture sites = approximately 5,000 km), after 366 days at liberty (DAL). We used these empirical mark-recapture data to estimate growth rates and maximum size for tiger sharks in Hawaii. We found that tiger sharks in Hawaii grow twice as fast as previously thought, on average reaching 340 cm TL by age 5, and attaining a maximum size of 403 cm TL. Our model indicates the fastest growing individuals attain 400 cm TL by age 5, and the largest reach a maximum size of 444 cm TL. The largest shark captured during our study was 464 cm TL but individuals >450 cm TL were extremely rare (0.005% of sharks captured). We conclude that tiger shark growth rates and maximum sizes in Hawaii are generally consistent with those in other regions, and hypothesize that a broad diet may help them to achieve this rapid growth by maximizing prey consumption rates.
View details for DOI 10.1371/journal.pone.0084799
View details for Web of Science ID 000329862500170
View details for PubMedID 24416287
View details for PubMedCentralID PMC3885620
- Stingray life history trade-offs associated with nursery habitat use inferred from a bioenergetics model MARINE BIOLOGY 2013; 160 (12): 3181-3192
- Age, growth and maturity of the brown stingray (Dasyatis lata) around Oahu, Hawai'i MARINE AND FRESHWATER RESEARCH 2012; 63 (6): 475-484