A review of long-distance movements by marine turtles, and the possible role of ocean currents

Sea turtle movements often occur in open-sea unsheltered areas, and are therefore likely to be influenced by major oceanographic processes. Only recently has work started to examine the possible relationships of these movements with dynamic oceanic features, and consequently a clear picture of such interaction is only available in a few cases. Newborn sea turtles are thought to rely on oceanic currents to reach their pelagic nursery habitats. The actual extent and timing of these developmental migrations are known for only a few populations, but these movements probably last several years and range over thousands of km. Large juveniles that have been tracked during their pelagic stage were found to make long-distance movements, sometimes swimming against the prevailing currents. Older juveniles of most species leave the pelagic habitat to recruit to neritic developmental habitats. This is a very poorly documented phase of the sea turtle life-cycle, and the few available indications show that turtles may have to swim actively for enormous distances to counterbalance their previous drift with the current. The course and extent of adult postnesting migrations vary greatly among different turtle species, but two main patterns are evident. Some species, like green, hawksbill and loggerhead turtles, shuttle between the nesting beach and a specific feeding area used for the entire inter-reproductive period. In these cases, individuals swim, rather than drift, to complete their journeys, with possible advection due to currents sometimes helping them to quickly reach their target, but sometimes providing navigational challenges. Other species such as the olive ridley and the leatherback turtle, leave the coastal nesting areas to reach the pelagic environment where they forage, and perform wandering movements. Major oceanographic processes (such as main currents and eddies) have been recently shown to have a remarkable influence on leatherback movements, making it questionable whether these journeys are to be considered migrations or, rather, prolonged stays in vast feeding areas.

Long-term satellite telemetry of the movements and habitat utilisation by green turtles in the Mediterranean

There is a relative paucity of data regarding the at-sea distribution and behaviour of marine turtles. This is especially true for the critically endangered green turtle Chelonia mydas population in the Mediterranean. Six adult female green turtles were equipped with satellite transmitters and tracked for periods of between 28 and 293 d following their final nesting of the season in northern Cyprus. Data elucidated hitherto unknown migratory pathways and highlighted the importance of North African coastal waters as feeding habitat for adults of this species. For three individuals, instruments transmitted detailed information on dive depth, dive duration and water temperature which afforded novel insights into behaviour during different stages of migration, feeding in the foraging grounds and most remarkably, during a period of midwinter diapause when water temperatures were generally below 25°C. Turtles showed fidelity to specific shallow inshore feeding areas and moved offshore to deeper wintering sites.

Meta-analysis of movements in Atlantic leatherback turtles during the nesting season : conservation implications

Despite decades of conservation efforts on the nesting beaches, the critical status of leatherback turtles shows that their survival predominantly depends on our ability to reduce at-sea mortality. Although areas where leatherbacks meet fisheries have been identified during the long distance movements between 2 consecutive nesting seasons, hot-spots of lethal interactions are still poorly defined within the nesting season, when individuals concentrate close to land. Here we report movements of satellite-tracked gravid leatherback turtles during the nesting season in Western Central Africa, South America and the Caribbean Sea, which account for about 70% of the world population. We show that during and at the end of the nesting season, leatherback turtles have the propensity to remain over the continental shelf, yet sometimes perform extended movements and may even nest in neighbouring countries. Leatherbacks exploit coastal commercial fishing grounds and face substantial accidental capture by regional coastal fisheries (e.g. at least 10% in French Guiana). This emphasises the need for regional conservation strategies to be developed at the ocean scale—both at sea and on land—to ensure the survival of the last leatherback turtles.

Vertical movements of North Sea Cod

Various air-breathing marine vertebrates such as seals, turtles and seabirds show distinct patterns of diving behaviour. For fish, the distinction between different vertical behaviours is often less clear-cut, as there are no surface intervals to differentiate between dives. Using data from acoustic tags (n = 23) and archival depth recorders attached to cod Gadus morhua (n = 92) in the southern North Sea, we developed a quantitative method of classifying vertical movements in order to facilitate an objective comparison of the behaviour of different individuals. This method expands the utilisation of data from data storage tags, with the potential for a better understanding of fish behaviour and enhanced individual based behaviour for improved ecosystem modelling. We found that cod were closely associated with the seabed for 90% of the time, although they showed distinct seasonal and spatial patterns in behaviour. For example, cod tagged in the southern North Sea exhibited high rates of vertical movement in spring and autumn that were probably associated with migration, while the vertical movements of resident cod in other areas were much less extensive and were probably related to foraging or spawning behaviours. The full reasons underlying spatial and temporal behavioural plasticity by cod in the North Sea warrant further investigation.

Thermal niche, large-scale movements and implications of climate change for a critically endangered marine vertebrate

Climate change is expected to have a number of impacts on biological communities including range extensions and contractions. Recent analyses of multidecadal data sets have shown such monotonic shifts in the distribution of plankton communities and various fish species, both groups for which there is a large amount of historical data on distribution. However, establishing the implications of climate change for the range of endangered species is problematic as historic data are often lacking. We therefore used a different approach to predict the implications of climate change for the range of the critically endangered planktivourous leatherback turtle (Dermochelys coriacea). We used long-term satellite telemetry to define the habitat utilization of this species. We show that the northerly distribution limit of this species can essentially be encapsulated by the position of the 15°C isotherm and that the summer position of this isotherm has moved north by 330 km in the North Atlantic in the last 17 years. Consequently, conservation measures will need to operate over ever-widening areas to accommodate this range extension.

Flexible foraging movements of Leatherback turtles across the North Atlantic Ocean

Some marine species have been shown to target foraging at particular hotspots of high prey abundance. However, we show here that in the year after a nesting season, female leatherback turtles (Dermochelys coriacea) in the Atlantic generally spend relatively little time in fixed hotspots, especially those with a surface signature revealed in satellite imagery, but rather tend to have a pattern of near continuous traveling. Associated with this traveling, distinct changes in dive behavior indicate that turtles constantly fine tune their foraging behavior and diel activity patterns in association with local conditions. Switches between nocturnal vs. diurnal activity are rare in the animal kingdom but may be essential for survival on a diet of gelatinous zooplankton where patches of high prey availability are rare. These results indicate that in their first year after nesting, leatherback turtles do not fit the general model of migration where responses to resources are suppressed during transit. However, their behavior may be different in their sabbatical years away from nesting beaches. Our results highlight the importance of whole-ocean fishing gear regulations to minimize turtle bycatch.

Building movements: directed improvisation performances : conversing with buildings; assisted falling

For these performances, the new Design Hub building will play the role of architectural surrounds used as spatial research devices, architectural agent and collaborator – by giving the building our attention we aim to bring it and its affordances explicitly into the collective body. In exploring the set of interlinked spaces in the Hub (with an emphasis, we propose, on the stairs) as “elaborately structured pretexts for action” , we anticipate that the beginnings of an approach may emerge and allow us to understand that when a person “flexes her muscles, a person [also] flexes her surroundings”. Arakawa and Gins offer ways to assist us in approaching architecture as a tentative constructing toward a holding in place – in which all modes of sensing and scales of action are exercised – through their notions of ‘architectural surround’ and ‘architectural body’ garnered from chapters ‘Notes for an Architectural Body’ and ‘Architectural Surround’ (Gins and Arakawa, 2002).

Building movements : installations : space-time twister; the rub

The two collaborative installations are part of the Building Movements event and aim to generate a shared ‘body of actions’. We are proposing to emphasise attention to constructed environments (buildings, clothes, landscapes…) as active participants in ecologies of lived experience, with particular interest in how we can more explicitly approach our environments as spatial research devices, i.e. how constructed environments can offer key questions and provocations in any research enquiry.

Spawning season movements of Macquarie perch (Macquaria australasica) in the Yarra River, Victoria

The Macquarie perch (Macquaria australasica) is a threatened fish species that inhabits rivers and impoundments in south-eastern Australia. Previous studies have shown that Macquarie perch in impoundments exhibit synchronised upstream spawning migrations to shallow, fast-flowing habitats in the lower reaches of inflowing streams. There has been little study of movement behaviours of entirely riverine populations of Macquarie perch despite this being the species’ natural habitat. Here, radio-telemetry is used to test the hypothesis that riverine populations exhibit synchronised migrations during the spawning season. Thirty Macquarie perch in the Yarra River, Victoria, a translocated population outside of the species’ natural range, were radio-tagged before the late spring–early summer spawning season and their movements followed over a 10-month period (May 2011 to February 2012). Tagged fish typically occupied restricted reaches of stream (<450 m). Sixteen of the fish undertook occasional upstream or downstream movements (~250–1000 m) away from their usual locations, particularly associated with large flow variations during the spawning season. There was no evidence of synchronised migratory behaviour or movement of multiple fish to specific locations or habitats during the spawning season. Whilst further research over more years is needed to comprehensively document the spawning-related behaviours of riverine Macquarie perch, our study demonstrates that management of riverine populations of this threatened species cannot necessarily be based on the model of spawning behaviour developed for lacustrine populations.

A possible anatomical and biomechanical explanation of the 10% rule used in the clinical assessment of prehensile hand movements and handed dominance

Abstract
A current doctrine in the dynamometric approach to determine lateralization of hand function states that in 10% of cases, the non-dominant hand will be stronger than the dominant hand. In this study, a novel MRI based modelling approach was applied to the first dorsal introsseus muscle (FDI), to determine whether the 10% rule may be applied to the FDI and may be partially explained by the arrangement of the anatomical components of the FDI.

Methods
Initially the force generated by the thumb segment during an isometric pushing task in the horizontal plane was measured from 25 strongly right-handed young males. Nine of these participants then had structural magnetic resonance imaging (sMRI) of the thumb and index osseous compartment. A modelling technique was developed to extract the muscle data and quantify the muscle line of action onto to the first metacarpal bone segment in order to quantify the muscle force at the point of momentary rotation – equilibrium.

Results
Eight of 25 subjects exhibited stronger force from the left hand. Six out of nine subjects from the MRI possessed significantly greater angles of attachment of the index osseous compartment on the left (non-dominant) hand. These six subjects also generated greater maximal isometric forces from the FDI of the left side. There was a significantly greater muscle volume for the right FDI muscle as compared to the left as measured from the reconstructed MRI slice data.

Conclusions
The calculated force produced by the muscle is related to the angle of attachment of the muscle to bone in the index osseous compartment. The MRI findings indicate that the 10% rule may be anatomically and biomechanically explained.

Validation of a trunk-mounted accelerometer to measure peak impacts during team sport movements

This study assessed the validity of an accelerometer to measure impacts in team sports. 76 participants completed a team sport circuit. Accelerations were collected concurrently at 100 Hz using an accelerometer and a 36-camera motion analysis system. The largest peak accelerations per movement were compared in 2 ways: i) pooled together and filtered at 13 different cut-off frequencies (range 6-25 Hz) to identify the optimal filtering frequency, and ii) the optimal cut-off frequency split into the 7 movements performed (n=532). Raw and 25-16 Hz filtering frequencies significantly overestimated and 6 Hz underestimated motion analysis peak accelerations (P <0.007). The 12 Hz filtered accelerometer data revealed the strongest relationship with motion analysis data (accuracy - 0.01±0.27 g, effect size - 0.01, agreement - 0.55 to 0.53 g, precision 0.27 g, and relative error 5.5%; P=1.00). The accelerometer underestimated peak accelerations during tackling and jumping, and overestimated during walking, jogging, sprinting and change of direction. Lower agreement and reduced precision were associated with sprinting, jumping and tackling. The accelerometer demonstrated an acceptable level of concurrent validity compared to a motion analysis system when filtered at a cut-off frequency of 12 Hz. The results advocate the use of accelerometers to measure movements in team sport.

Risk factors for coronary heart disease among Asian Indians living in Australia

The aim of this study was to assess the coronary heart disease risk factors in the Asian Indian community living in a large city in Australia. A cross-sectional survey was conducted at the Australia India Friendship Fair in 2010. All people of Asian Indian descent who attended the Fair and visited the health promotion stall were eligible to participate in the study if they self-identified as of Asian Indian origin, were aged between 18 and 80 years, and were able to speak English. Blood pressure, blood glucose, waist circumference, height, and weight were measured by a health professional. Smoking, cholesterol levels, and physical activity status were obtained through self-reports. Data were analyzed for 169 participants. More than a third of the participants under the age of 65 years had high blood pressure. Prevalence of diabetes (16%) and obesity (61%) was significantly higher compared with the national average. Ten women identified themselves as smokers. Physical activity patterns were similar to that of the wider Australian population. The study has provided a platform for raising awareness among nurses and promoting advocacy on the cardiovascular risk among Asian Indians. Strategies involving Asian Indian nurses and other Asian Indian health professionals as well as support from the private and public sectors can assist in the reduction of the coronary heart disease risk factors among this extremely susceptible population.