Were Multiple Stressors a \u27Perfect Storm\u27 for Northern Gulf of Mexico Bottlenose Dolphins (Tursiops truncatus) in 2011?

An unusual number of near term and neonatal bottlenose dolphin (Tursiops truncatus) mortalities occurred in the northern Gulf of Mexico (nGOM) in 2011, during the first calving season after two well documented environmental perturbations; sustained cold weather in 2010 and the Deepwater Horizon oil spill (DWHOS). Preceding the stranding event, large volumes of cold freshwater entered the nGOM due to unusually large snowmelt on the adjacent watershed, providing a third potential stressor. We consider the possibility that this extreme cold and freshwater event contributed to the pattern of perinatal dolphin strandings along the nGOM coast. During the 4-month period starting January 2011, 186 bottlenose dolphins, including 46% perinatal calves (nearly double the percentage for the same time period from 2003-2010) washed ashore from Louisiana to western Florida. Comparison of the frequency distribution of strandings to flow rates and water temperature at a monitoring buoy outside Mobile Bay, Alabama (the 4th largest freshwater drainage in the U. S.) and along the nGOM coast showed that dolphin strandings peaked in Julian weeks 5, 8, and 12 (February and March), following water temperature minima by 2-3 weeks. If dolphin condition was already poor due to depleted food resources, bacterial infection, or other factors, it is plausible that the spring freshet contributed to the timing and location of the unique stranding event in early 2011. These data provide strong observational evidence to assess links between the timing of the DWHOS, other local environmental stressors, and mortality of a top local predator. Targeted analyses of tissues from stranded dolphins will be essential to define a cause of death, and our findings highlight the importance of considering environmental data along with biological samples to interpret stranding patterns during and after an unusual mortality event

Addition of Passive Acoustic Telemetry Mitigates Lost Data From Satellite-Tracked Manatees

Satellite-tracked manatees routinely lose satellite tags or tag functionality, resulting in the loss of valuable data on migration and habitat use patterns. Fortunately, some movement data from these animals remain salvageable because manatees typically retain a peduncle belt containing an acoustic transmitter that can be detected with a submersible hydrophone. We deployed an array of moored datalogging hydrophones at key locations in our study area to detect manatee belt-embedded acoustic transmitters, a technique not typically used to track manatees. Our array was successful in detecting five tagged manatees, and concurrently detected compatible acoustic tags of other estuarine fauna (e.g. Bull Sharks) tagged by local researchers. Moored datalogging hydrophones, therefore, provided a method to mitigate the loss of satellite tags from estuarine megafauna, and enhanced collaborative opportunities with researchers who tagged other species using compatible equipment

Convergence of marine megafauna movement patterns in coastal and open oceans

Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences of the United States of America 115 (2018): 3072-3077, doi:10.1073/pnas.1716137115.The extent of increasing anthropogenic impacts on large marine vertebrates partly depends on the animals’ movement patterns. Effective conservation requires identification of the key drivers of movement including intrinsic properties and extrinsic constraints associated with the dynamic nature of the environments the animals inhabit. However, the relative importance of intrinsic versus extrinsic factors remains elusive. We analyse a global dataset of 2.8 million locations from > 2,600 tracked individuals across 50 marine vertebrates evolutionarily separated by millions of years and using different locomotion modes (fly, swim, walk/paddle). Strikingly, movement patterns show a remarkable convergence, being strongly conserved across species and independent of body length and mass, despite these traits ranging over 10 orders of magnitude among the species studied. This represents a fundamental difference between marine and terrestrial vertebrates not previously identified, likely linked to the reduced costs of locomotion in water. Movement patterns were primarily explained by the interaction between species-specific traits and the habitat(s) they move through, resulting in complex movement patterns when moving close to coasts compared to more predictable patterns when moving in open oceans. This distinct difference may be associated with greater complexity within coastal micro-habitats, highlighting a critical role of preferred habitat in shaping marine vertebrate global movements. Efforts to develop understanding of the characteristics of vertebrate movement should consider the habitat(s) through which they move to identify how movement patterns will alter with forecasted severe ocean changes, such as reduced Arctic sea ice cover, sea level rise and declining oxygen content.Workshops funding granted by the UWA Oceans Institute, AIMS, and KAUST. AMMS was supported by an ARC Grant DE170100841 and an IOMRC (UWA, AIMS, CSIRO) fellowship; JPR by MEDC (FPU program, Spain); DWS by UK NERC and Save Our Seas Foundation; NQ by FCT (Portugal); MMCM by a CAPES fellowship (Ministry of Education)

Self-grooming response of meadow voles to the odor of opposite-sex conspecifics in relation to the dietary protein content of both sexes

Many animals self-groom when they encounter the scent marks of opposite-sex conspecifics. Self-grooming transmits odiferous substances that contain information about the groomer\u27s condition, which is affected by its nutritional state. We tested the hypothesis that the amount of time that individuals self-groom to opposite-sex conspecifics is affected by the amount of protein in their diet and that of the scent donor. We did so by feeding meadow voles (Microtus pennsylvanicus) a diet containing 9%, 13%, or 22% dietary protein for 30 d and observing their self-grooming behavior when they were exposed to bedding scented by an opposite-sex conspecific (odor donor) fed one of the three diets, or fresh cotton bedding (control). The hypothesis was partially supported. We found that the protein content of the diet of male and female groomers did not affect the amount of time they self-groomed. However, the protein content of the diet of male odor donors affected the amount of time that female voles spent self-grooming. Female voles self-groomed more in response to male odor donors fed a 22% protein-content diet than to those produced by male odor donors fed either a 9% or a 13% protein-content diet. Interestingly, the amount of time males self-groomed was not affected by the protein content of the diet of the female odor donor. These results may, in part, be explained by the natural history of free-living meadow voles, sex differences in costs associated with mate attraction and reproduction, and the direct or indirect benefits that females receive from males fed a diet high in protein content. © 2008 The Authors

Were multiple stressors a 'perfect storm' for northern Gulf of Mexico bottlenose dolphins (Tursiops truncatus) in 2011?

An unusual number of near term and neonatal bottlenose dolphin (Tursiops truncatus) mortalities occurred in the northern Gulf of Mexico (nGOM) in 2011, during the first calving season after two well documented environmental perturbations; sustained cold weather in 2010 and the Deepwater Horizon oil spill (DWHOS). Preceding the stranding event, large volumes of cold freshwater entered the nGOM due to unusually large snowmelt on the adjacent watershed, providing a third potential stressor. We consider the possibility that this extreme cold and freshwater event contributed to the pattern of perinatal dolphin strandings along the nGOM coast. During the 4-month period starting January 2011, 186 bottlenose dolphins, including 46% perinatal calves (nearly double the percentage for the same time period from 2003-2010) washed ashore from Louisiana to western Florida. Comparison of the frequency distribution of strandings to flow rates and water temperature at a monitoring buoy outside Mobile Bay, Alabama (the 4(th) largest freshwater drainage in the U.S.) and along the nGOM coast showed that dolphin strandings peaked in Julian weeks 5, 8, and 12 (February and March), following water temperature minima by 2-3 weeks. If dolphin condition was already poor due to depleted food resources, bacterial infection, or other factors, it is plausible that the spring freshet contributed to the timing and location of the unique stranding event in early 2011. These data provide strong observational evidence to assess links between the timing of the DWHOS, other local environmental stressors, and mortality of a top local predator. Targeted analyses of tissues from stranded dolphins will be essential to define a cause of death, and our findings highlight the importance of considering environmental data along with biological samples to interpret stranding patterns during and after an unusual mortality event

Total bottlenose dolphin strandings by state (1 January – 30 April 2011).

<p>LA  =  Louisiana, MS  =  Mississippi, AL  =  Alabama, FL  =  Florida. NMFS independently validated Marine Mammal Health and Stranding Response Program data up to 2008, and data from February 2010 through August 2011 have been audited by NMFS. Data are subject to change prior to NMFS validation.</p

Dolphin strandings compared to water temperature through time.

<p>Total biweekly bottlenose dolphin strandings reported in Louisiana (LA), Mississippi (MS), Alabama (AL), and Florida (FL) from January 2003 through April 2011 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041155#pone.0041155-NOAA2" target="_blank">[12]</a> compared to biweekly mean surface water temperature at Mobile Bay, AL. Potential stressors: I  =  Winter 2010, II  =  DWHOS in the nGOM, III  =  spring freshet.</p

Gulf of Mexico coastal SST in 2011.

<p><b>A</b>) Weekly mean sea surface temperature (SST) for near shore areas in the nGOM from 1 January - 30 April 2011. The dashed line is the high-frequency temperature data from Mobile Bay (DPHA1 buoy) shown in Fig. 3A. <b>B</b>) 1° longitude×2° latitude grid boxes in which NOAA Weekly Global Sea Surface Temperature SST Model Outputs from OIV2 Optimum Interpolation Analysis (<a href="http://www.cpc.ncep.noaa.gov/products/GIS/GIS_DATA/sst_oiv2/index.php" target="_blank">http://www.cpc.ncep.noaa.gov/products/GIS/GIS_DATA/sst_oiv2/index.php</a>) were averaged. Inset dots in <b>B</b> indicate sites from which high-frequency local water flow (1) and surface water temperature and salinity (2) data were collected at Mobile Bay, AL. Site 2 is the DPHA1 buoy.</p

Dolphin strandings in 2011.

<p><b>A</b>) Total weekly bottlenose dolphin strandings for each state compared to surface water temperature (30 min intervals), flow (15 min intervals), and salinity (30 min intervals) measured at Mobile Bay, AL. <b>B</b>) Weekly perinatal dolphin strandings, separated by state (following the same legend as panel A). <b>C</b>) Total weekly bottlenose dolphin strandings, separated by carcass condition on the day of response in 2011. Carcass condition is reported using NMFS standard 5-point code in which 1 is live stranded, 2 is freshly dead, and 5 is most highly decomposed. NR  =  Not reported.</p

Comparison of peak dolphin strandings to peak water flow and temperature declines during January – March 2011.

<p>AL  =  sites near Mobile Bay, Alabama during January – March 2011 and correspond to data in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041155#pone-0041155-g003" target="_blank">Fig. 3A</a>. GOM  =  Gulf-wide (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041155#pone-0041155-g005" target="_blank">Fig. 5</a>) for the same period.</p