Project description:An 8X15k oligonucleotide microarray was developed consisting of 2334 E. glacialis probes and 2166 Tursiops truncatus probes and used to measure the transcriptome level effects of right whale kidney fibroblast cells exposed to cadmium. Cells were exposed to three concentrations of cadmium chloride (CdCl2) for three exposure times. Cells exposed to 10-6M CdCl2 for 4 hours and 24 hours showed upregulated genes involved in protection from metal toxicity, oxidative stress, protein renaturation, apoptosis inhibition, and several regulators of cellular processes. Downregulated genes represented a suite of functions including cell proliferation, transcription regulation, actin polymerization, and stress fiber synthesis. The collection of differentially expressed genes in this study support proposed mechanisms of cadmium-induced apoptosis such as mitochondrial membrane potential collapse, reactive oxygen species (ROS) influx, and cell cycle arrest. The results confirm the right whale microarray as a reproducible tool in measuring differentiated gene expression and should be a valuable asset for transcriptome analysis of other baleen whales and potential health assessment protocols.
Project description:An 8X15k oligonucleotide microarray was developed consisting of 2334 E. glacialis probes and 2166 Tursiops truncatus probes and used to measure the transcriptome level effects of right whale kidney fibroblast cells exposed to cadmium. Cells were exposed to three concentrations of cadmium chloride (CdCl2) for three exposure times. Cells exposed to 10-6M CdCl2 for 4 hours and 24 hours showed upregulated genes involved in protection from metal toxicity, oxidative stress, protein renaturation, apoptosis inhibition, and several regulators of cellular processes. Downregulated genes represented a suite of functions including cell proliferation, transcription regulation, actin polymerization, and stress fiber synthesis. The collection of differentially expressed genes in this study support proposed mechanisms of cadmium-induced apoptosis such as mitochondrial membrane potential collapse, reactive oxygen species (ROS) influx, and cell cycle arrest. The results confirm the right whale microarray as a reproducible tool in measuring differentiated gene expression and should be a valuable asset for transcriptome analysis of other baleen whales and potential health assessment protocols. 35 Samples were analyzed representing 3 biological replicates for each treatment and corresponding controls except treatment 4hour_0.01uMCdCl2 had only two biological replicates due to spot intensity values. There are 3 spot replicates/probe on the array, along with Agilent control grid specific for 8X15K arrays, and 4 Karenia brevis sequences used as a negative control (K.brevis.chlorophyllA/Bbindingprotein, K.brevis.flavodoxin,K.brevis.photolyase,K.brevis.photosystemcoreprotein).
Project description:North Atlantic right whales (Eubalaena glacialis) feed during the spring and early summer in marine waters off the northeast coast of North America. Their food primarily consists of planktonic copepods, Calanus finmarchicus, which they consume in large numbers by ram filter feeding. The coastal waters where these whales forage are turbid, but they successfully locate copepod swarms during the day at depths exceeding 100 m, where light is very dim and copepod patches may be difficult to see. Using models of E. glacialis visual sensitivity together with measurements of light in waters near Cape Cod where they feed and of light attenuation by living copepods in seawater, we evaluated the potential for visual foraging by these whales. Our results suggest that vision may be useful for finding copepod patches, particularly if E. glacialis searches overhead for silhouetted masses or layers of copepods. This should permit the whales to locate C. finmarchicus visually throughout most daylight hours at depths throughout their foraging range. Looking laterally, the whales might also be able to see copepod patches at short range near the surface.This article is part of the themed issue 'Vision in dim light'.
Project description:North Atlantic right whales (NARW), Eubalaena glacialis, were nearly exterminated by historical whaling. Their abundance slowly increased up until 2010, to a maximum of fewer than 500 whales, and since then they have been in decline. We assessed the extent to which the relatively slow increase demonstrated by NARW was intrinsic, and how much could be due to anthropogenic impacts. In order to do so, we first compared calf counts of three populations of Southern right whales (SRW), E. australis, with that of NARW, over the period 1992-2016. By this index, the annual rate of increase of NARW was approximately one-third of that of SRW. Next we constructed a population projection model for female NARW, using the highest annual survival estimates available from recent mark-resight analysis, and assuming a four-year calving interval. The model results indicated an intrinsic rate of increase of 4% per year, approximately twice that observed, and that adult female mortality is the main factor influencing this rate. Necropsy records demonstrate that anthropogenic mortality is the primary cause of known mortality of NARW. Anthropogenic mortality and morbidity has limited the recovery of NARW, and baseline conditions prior to their recent decline were already jeopardizing NARW recovery.
Project description:The coastal waters off the southeastern United States (SEUS) are a primary wintering ground for the endangered North Atlantic right whale (Eubalaena glacialis), used by calving females along with other adult and juvenile whales. Management actions implemented in this area for the recovery of the right whale population rely on accurate habitat characterization and the ability to predict whale distribution over time. We developed a temporally dynamic habitat model to predict wintering right whale distribution in the SEUS using a generalized additive model framework and aerial survey data from 2003/2004 through 2012/2013. We built upon previous habitat models for right whales in the SEUS and include data from new aerial surveys that extend the spatial coverage of the analysis, particularly in the northern portion of this wintering ground. We summarized whale sightings, survey effort corrected for probability of whale detection, and environmental data at a semimonthly resolution. Consistent with previous studies, sea surface temperature (SST), water depth, and survey year were significant predictors of right whale relative abundance. Additionally, distance to shore, distance to the 22°C SST isotherm, and an interaction between time of year and latitude (to account for the latitudinal migration of whales) were also selected in the analysis presented here. Predictions from the model revealed that the location of preferred habitat differs within and between years in correspondence with variation in environmental conditions. Although cow-calf pairs were rarely sighted in the company of other whales, there was minimal evidence that the preferred habitat of cow-calf pairs was different than that of whale groups without calves at the scale of this study. The results of this updated habitat model can be used to inform management decisions for a migratory species in a dynamic oceanic environment.