17 research outputs found
Frequency of Injuries from Line Entanglements, Killer Whales, and Ship Strikes on Bering-Chukchi-Beaufort Seas Bowhead Whales
We analyzed scarring data for Bering-Chukchi-Beaufort (BCB) Seas bowhead whales (Balaena mysticetus) harvested by Alaska Native hunters to quantify the frequency of line entanglement, ship strikes, and killer whale-inflicted injuries. We had 904 records in our database for whales landed between 1990 and 2012, and after data quality screening, we found 521 records containing information on scarring. Logistic regression was used to evaluate different combinations of explanatory variables (i.e., body length, sex, year, year-group) to develop a prediction model for each scar type. We also list bowhead whales that were harvested, found dead, or observed alive entangled in commercial line/fishing gear. Our findings suggest that about 12% of harvested bowheads show entanglement scars. Their frequency is highly correlated with body length and sex: about 50% of very large bowheads (> 17 m) show such scars, while whales under 9 m rarely do, and males show a significantly higher rate than females. Scars associated with ship strikes are infrequent and occur on ~2% of all harvested whales; body length, sex, and year were not significant factors. Scarring from attempted killer whale predation was evident on ~8% of landed whales. As with entanglement injuries, the frequency of killer whale scars was much higher (> 40%) on whales more than 16 m in length and statistically more frequent in the second half of the study (2002 â 12). Increased killer whale injuries in the recent decade are consistent with studies conducted on bowheads of the Eastern Canada-West Greenland population. The findings presented here reflect the most thorough analysis of injury rates from entanglement, ships, and killer whales for the BCB bowheads conducted to date. They indicate that (1) entanglement rates primarily from pot fishing gear (crab or cod or both) are relatively high for very large and presumably older bowheads, (2) collisions with ships are infrequent at present, and (3) scarring from killer whales is frequent on very large adult whales (> 17 m). Considering that bowhead habitat is changing rapidly (e.g., sea ice reduction), industrial ship traffic in the Arctic is increasing, and commercial fishing operations are expanding to the north, we strongly recommend that monitoring of scarring and injuries on harvested bowheads continue into the future as a means of documenting change.Nous avons analysĂ© les donnĂ©es sur les cicatrices que portent les baleines borĂ©ales (Balaena mysticetus) des mers de BĂ©ring, des Tchouktches et de Beaufort capturĂ©es par des chasseurs autochtones de lâAlaska afin de quantifier la frĂ©quence dâemmĂȘlements dans des filets de pĂȘche, de collisions avec des navires et de blessures infligĂ©es par des Ă©paulards. Notre base de donnĂ©es contenait 904 enregistrements portant sur des baleines prises entre 1990 et 2012 et, aprĂšs une sĂ©lection des donnĂ©es selon leur qualitĂ©, nous avons trouvĂ© 521 enregistrements comptant de lâinformation sur des cicatrices. Une mĂ©thode de rĂ©gression logistique a Ă©tĂ© utilisĂ©e pour Ă©valuer diffĂ©rentes combinaisons de variables explicatives (longueur corporelle, sexe, annĂ©e et annĂ©e-groupe, par exemple) afin de concevoir un modĂšle prĂ©dictif pour chaque type de cicatrice. Nous Ă©numĂ©rons Ă©galement les baleines borĂ©ales retrouvĂ©es emmĂȘlĂ©es dans des engins ou des filets de pĂȘche commerciale qui ont Ă©tĂ© capturĂ©es, trouvĂ©es mortes ou observĂ©es vivantes. Nos dĂ©couvertes suggĂšrent quâenviron 12 % des baleines borĂ©ales capturĂ©es portent des cicatrices causĂ©es par lâemmĂȘlement. La frĂ©quence des cicatrices est Ă©troitement liĂ©e Ă la longueur corporelle et au sexe : environ 50 % des baleines borĂ©ales de trĂšs grande taille (> 17 m) montrent de telles cicatrices, tandis que les baleines mesurant moins de 9 m portent rarement de telles cicatrices. Par ailleurs, les mĂąles affichent beaucoup plus de cicatrices que les femelles. Les cicatrices reliĂ©es Ă des collisions avec des navires sont rares et nâapparaissent que sur environ 2 % de toutes les baleines capturĂ©es; la longueur corporelle, le sexe et lâannĂ©e nâĂ©taient pas des facteurs importants. Les cicatrices causĂ©es par des tentatives de prĂ©dation par les Ă©paulards Ă©taient apparentes sur environ 8 % des baleines prises. Comme pour les blessures causĂ©es par lâemmĂȘlement, la frĂ©quence des cicatrices causĂ©es par des Ă©paulards Ă©tait beaucoup plus Ă©levĂ©e(> 40 %) sur les baleines mesurant plus de 16 m de longueur et statistiquement plus frĂ©quente dans la deuxiĂšme partie de lâĂ©tude (2002â2012). Lâaugmentation des blessures causĂ©es par des Ă©paulards au cours de la derniĂšre dĂ©cennie concorde avec les Ă©tudes rĂ©alisĂ©es sur la population des baleines borĂ©ales de lâest du Canada et de lâouest du Groenland. Les rĂ©sultats prĂ©sentĂ©s dans cette Ă©tude reflĂštent lâanalyse la plus profonde du taux de blessures causĂ©es par lâemmĂȘlement, les navires et les Ă©paulards sur les baleines borĂ©ales des mers de BĂ©ring, des Tchouktches et de Beaufort Ă avoir Ă©tĂ© rĂ©alisĂ©e jusquâĂ prĂ©sent. Les observations indiquent que : 1) le taux dâemmĂȘlement dĂ©coulant principalement des engins ou casiers de pĂȘche (crabe ou morue ou les deux) est relativement Ă©levĂ© chez les baleines borĂ©ales de trĂšs grande taille et probablement plus vieilles, 2) les collisions avec les navires sont rares en ce moment, et 3) les cicatrices causĂ©es par des Ă©paulards sont frĂ©quentes chez les baleines adultes de trĂšs grande taille (> 17 m). Ătant donnĂ© le changement rapide de lâhabitat de la baleine borĂ©ale (diminution des glaces marines, par exemple), lâaugmentation de la circulation maritime industrielle dans lâArctique et lâintensification des opĂ©rations de pĂȘche commerciale au nord, nous recommandons fortement de continuer de surveiller les cicatrices et les blessures des baleines borĂ©ales capturĂ©es afin de documenter les changements
Spectral reflectance of whale skin above the sea surface: a proposed measurement protocol
Great whales have been detected using veryâhighâresolution satellite imagery, suggesting this technology could be used to monitor whales in remote areas. However, the application of this method to whale studies is at an early developmental stage and several technical factors need to be addressed, including capacity for species differentiation and the maximum depth of detection in the water column. Both require knowledge of the spectral reflectance of the various whale species just above the sea surface, as when whales bodies break the surface of the water to breath, log or breach, there is, at times, no sea water between the whale's skin and the satellite sensor. Here we tested whether such reflectance could be measured on dead whale tissue. We measured the spectral reflectance of fresh integument collected during the bowhead subsistence harvest, and of thawed integument samples from various species obtained following strandings and stored at â20°C. We show that fresh and thawed samples of whale integument have different spectral properties. The reflectance of fresh samples was higher than the reflectance of thawed samples, as integument appears to darken after death and with time, even under frozen conditions. In this study, we present the first whale reflectance estimates (without the influence of sea water and for dead tissue). These provide a baseline for additional work, needed to advance the use of satellite imagery to monitor whales and facilitate their conservation
Environmental change and potential impacts: applied research priorities for Alaska\u27s North Slope
Long-Term Cold Acclimation Extends Survival Time at 0°C and Modifies the Metabolomic Profiles of the Larvae of the Fruit Fly Drosophila melanogaster
Drosophila melanogaster is a chill-susceptible insect. Previous studies on this fly focused on acute direct chilling injury during cold shock and showed that lower lethal temperature (LLT, approximately -5°C) exhibits relatively low plasticity and that acclimations, both rapid cold hardening (RCH) and long-term cold acclimation, shift the LLT by only a few degrees at the maximum.We found that long-term cold acclimation considerably improved cold tolerance in fully grown third-instar larvae of D. melanogaster. A comparison of the larvae acclimated at constant 25°C with those acclimated at constant 15°C followed by constant 6°C for 2 d (15°Câ6°C) showed that long-term cold acclimation extended the lethal time for 50% of the population (Lt(50)) during exposure to constant 0°C as much as 630-fold (from 0.137 h to 86.658 h). Such marked physiological plasticity in Lt(50) (in contrast to LLT) suggested that chronic indirect chilling injury at 0°C differs from that caused by cold shock. Long-term cold acclimation modified the metabolomic profiles of the larvae. Accumulations of proline (up to 17.7 mM) and trehalose (up to 36.5 mM) were the two most prominent responses. In addition, restructuring of the glycerophospholipid composition of biological membranes was observed. The relative proportion of glycerophosphoethanolamines (especially those with linoleic acid at the sn-2 position) increased at the expense of glycerophosphocholines.Third-instar larvae of D. melanogaster improved their cold tolerance in response to long-term cold acclimation and showed metabolic potential for the accumulation of proline and trehalose and for membrane restructuring
Lichen species across Alaska produce highly active and stable ice nucleators
Forty years ago, lichens were identified as extraordinary biological ice nucleators (INs) that enable ice formation at temperatures close to 0 °C. By employing INs, lichens thrive in freezing environments that surpass the physiological limits of other vegetation, thus making them the majority of vegetative biomass in northern ecosystems. Aerosolized lichen INs might further impact cloud glaciation and have the potential to alter atmospheric processes in a warming Arctic. Despite the ecological importance and formidable ice nucleation activities, the abundance, diversity, sources, and role of ice nucleation in lichens remain poorly understood. Here, we investigate the ice nucleation capabilities of lichens collected from various ecosystems across Alaska. We find ice-nucleating activity in lichen to be widespread, particularly in the coastal rainforest of Southeast Alaska. Across 29 investigated lichen, all species show ice nucleation temperatures above â15 °C and ~30 % initiate freezing at temperatures above â6 °C. Concentration series of lichen ice nucleation assays in combination with statistical analysis reveal that the lichens contain two subpopulations of INs, similar to previous observations in bacteria. However, unlike the bacterial INs, the lichen INs appear as independent subpopulations resistant to freeze-thaw cycles and against temperature treatment. The ubiquity and high stability of the lichen INs suggest that they can impact local atmospheric processes and that ice nucleation activity is an essential trait for their survival in cold environments
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Whale reflectance spectra
A list of whale reflectance spectra, pre-processed (see publication) with information about the species, collection method, and the set up.MAVA Foundation (project 16035 âStudying whales from spaceâ), NERC, BB Roberts Fund, the Cambridge Philosophical Society (S54/104/18) and Prescott Stranding grants to UNCW. The samples of whale integument were collected under the following permit: Stranding Agreements between the NOAA, National Marine Fisheries Service and network participants: IFAW and UNCW, NOAA stranding Letter of Authorization to UNCW, NOAA Marine Mammal Health and Stranding Response Permits 932-1489, 932-1905, 17355, 18786, and 18786, Authorization from the NOAA NMFS NE Regional Office, NE and SE US NMFS MMPA Regional Letters of Authorization, under NMFS permit to Dr Teri Rowles. The integument samples from the bowhead subsistence harvest used to measure the reflectance were under the NMFS Permit No. 21386, however, samples were not retained