ALBERT

Description: Most countries require monitoring of marine mammals near seismic surveys in order to estimate potential impacts and/or to trigger appropriate mitigations measures. Typically, monitoring involves the use of visual observations by trained personnel, which are generally limited by periods of daylight with good visibility (e.g. not foggy etc.); even in perfect weather, marine mammal presence may be missed by the human observers. The ability to detect marine mammals missed by observers, as well as the ability to extend the observation period of marine mammals into the nightime and into other poor visibility conditions, would increase the activity time for industry and the accuracy of monitoring/mitigation compliance efforts. One technology for improving the effectiveness of monitoring is the use of infrared (IR) imaging devices. IR technology measures the heat radiated from an object, and the heat contrast between two juxtaposed objects. IR technology is well suited to marine mammal monitoring, since all marine mammals must come to the surface to breathe, and IR imaging often gives a clear temperature contrast between the animal and the water, making for easy detection through both visual and automated observations. An advanced IR camera system capable of simultaneously monitoring 360° around a vessel was tested during a two month seismic operation in the Alaskan Chukchi Sea in 2010. This particular installation allowed monitoring of 280° ahead and to the sides of the vessel with a picture refresh rate of 5 hertz (Hz). The IR pictures were displayed in real-time on two monitors, and video was recorded during marine mammal sightings for retrospective analyses. Approximately 180 whale blows were detected in the recorded IR imagery. Smaller whales (Dall’s porpoise) were detectable at distances of several hundred meters, while blows from large baleen whales were seen at distances of up to 8 kilometers (km). The IR camera was also able to detect walrus that surfaced within 1 km of the vessel, with some detection out to a maximum distance of 1.5 km. Sea state and visibility hampered the detectability for marine mammals similarly to human visual observations, but the IR camera offers excellent observations possibilities at nightime. In the tested configuration, the IR camera system showed substantial promise for improving the effectiveness of detecting marine mammals at the surface during daylight hours, and even more detection capabilities at night. In additiona, the IR camera also allows precise measurement of the distance of the marine mammal to the seismic vessel.

Description: Important processes of living cells, including intracellular transport, cell crawling, contraction, division, and mechanochemical signal transduction, are controlled by cytoskeletal (CSK) dynamics. CSK dynamics can be measured by tracking the motion of CSK-bound particles. Particle motion has been reported to follow a superdiffusive behavior that is believed to arise from ATP-driven intracellular stress fluctuations generated by polymerization processes and motor proteins. The power spectrum of intracellular stress fluctuations has been suggested to decay with 1/2 (Lau et al, Phys Rev Lett 91:198101). Here we report direct measurements of cellular force fluctuations that are transmitted to the extracellular matrix, and compared them with the spontaneous motion of CSK-bound beads. Fibronectin coated fluorescent beads (Ø 1 m) were bound to the CSK of confluent human vascular endothelial cells. Forces transmitted to the extracellular matrix (ECM) were quantified by plating these cells onto a collagen coated elastic polyacrylamide hydrogel, and measuring the gel deformation from the displacement of embedded fluorescent beads (Ø 0.5 m). Bead motion of both CSK-bound and ECM-bound beads were measured with nanometer-resolution and expressed as mean square displacement (MSD). The MSD of both CSK-bound and ECM-bound beads displayed a superdiffusive behavior that was well described by a power law: MSD = a*t^b. Surprisingly, we found an identical power law exponent for both CSK-bound and ECM-bound beads of b = 1.6. This finding suggests that the spontaneous motion of CSK-bound beads is driven by stress fluctuations with a 1/ b+1 power spectrum. This result is consistent with the notion that CSK dynamics and CSK stress fluctuations are closely coupled.

Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS 11 (2016): e0150660, doi:10.1371/journal.pone.0150660.

Description: Sperm whales are present in the Canary Islands year-round, suggesting that the archipelago is an important area for this species in the North Atlantic. However, the area experiences one of the highest reported rates of sperm whale ship-strike in the world. Here we investigate if the number of sperm whales found in the archipelago can sustain the current rate of ship-strike mortality. The results of this study may also have implications for offshore areas where concentrations of sperm whales may coincide with high densities of ship traffic, but where ship-strikes may be undocumented. The absolute abundance of sperm whales in an area of 52933 km2, covering the territorial waters of the Canary Islands, was estimated from 2668 km of acoustic line-transect survey using Distance sampling analysis. Data on sperm whale diving and acoustic behaviour, obtained from bio-logging, were used to calculate g(0) = 0.92, this is less than one because of occasional extended periods when whales do not echolocate. This resulted in an absolute abundance estimate of 224 sperm whales (95% log-normal CI 120–418) within the survey area. The recruitment capability of this number of whales, some 2.5 whales per year, is likely to be exceeded by the current ship-strike mortality rate. Furthermore, we found areas of higher whale density within the archipelago, many coincident with those previously described, suggesting that these are important habitats for females and immature animals inhabiting the archipelago. Some of these areas are crossed by active shipping lanes increasing the risk of ship-strikes. Given the philopatry in female sperm whales, replacement of impacted whales might be limited. Therefore, the application of mitigation measures to reduce the ship-strike mortality rate seems essential for the conservation of sperm whales in the Canary Islands.