). Although vessels only slow down when mandated, they change their routing voluntarily. Compliance rates with voluntary recommended routes steadily increased during this period, from 43% prior to rulemaking, to 52% during the first year, 84% in the second year, and 96% in the final year of the study. Combining reduced speeds with recommended routes reduces the probability of right whale mortality from ships by 71.9% from the pre-implementation period. These results support long-term implementation of both vessel-speed reduction and restricted vessel routes for the survival and recovery of the North Atlantic right whale.
Recent surveys of wind energy areas offshore of Massachusetts and Rhode Island (USA) have demonstrated that they encompass habitat used by the Endangered North Atlantic right whale Eubalaena glacialis. Prior to 2011, little systematic survey effort had been conducted in the area. The Bureau of Ocean Energy Management and the state of Massachusetts supported 3.5 yr of twice-monthly aerial surveys by the Northeast Large Pelagic Survey Collaborative (NLPSC). Additional survey teams including the Northeast Fisheries Science Center and the Center for Coastal Studies have collected sightings data in the region. Data systematically collected by the NLPSC allowed analyses of monthly sightings rates, sightings per unit effort, and hot spots which provided information on current temporal and spatial use patterns. Abundance estimates for each season-year (i.e. a 3 mo period within a given survey year) were calculated. Behaviors observed included feeding and surface active groups. Photo-identification of whales since 2010 yielded a minimum count of 196 unique individuals (annual average = 35), or over one-third of the current population estimate. Analyses of demographics of these individuals revealed that 34 known calving females (30% of the total currently presumed alive) visited the study area. These results demonstrate consistent annual use of this area by a significant portion of the E. glacialis population, with a strong correlation between season and presence. These findings can inform management activities and development planning, and be used as a baseline dataset for assessing long-term impacts to the species.
Effective conservation of endangered North Atlantic right whales Eubalaena glacialis requires information about their spatio-temporal distribution. Understanding temporal distribution is particularly important, because a portion of the population migrates between high-latitude summer feeding grounds off the northeastern US and Canadian Maritimes coasts and lower-latitude calving and wintering grounds off the southeastern US coast (SEUS). Here, we modeled SEUS residence patterns using photo-identification data from coastal South Carolina, Georgia, and Florida from 7 winter seasons (2004/2005-2010/2011). We used multistate open robust design models to evaluate effects of reproductive status, demographic group, and environmental conditions on SEUS residence. Model estimates accounted for temporal variation and imperfect detection and provided probabilities of entering the SEUS, staying in the SEUS, and being sighted in the SEUS. We also derived estimates for residence time and seasonal abundance. We observed staggered arrival and departure patterns and demographic differences in residence patterns that are characteristic of a differential migration strategy. Calving females arrived ear liest and, in most seasons, had mean residence periods more than twice as long as other demographic groups. Conversely, adult males arrived the latest and had the shortest residence times. Within-season detection was positively influenced by survey effort, and overall seasonal mean (± SE) detection rate estimates ranged from 0.83 ± 0.08 for non-calving adult females to 0.98 ± 0.02 for calving females. Results provide insights into right whale behavior, biology, and temporal distribution in the SEUS and can be used to evaluate spatially and temporally dynamic management measures.
North Atlantic right whales (Eubalaena glacialis) are critically endangered, and recent changes in distribution patterns have been a major management challenge. Understanding the role that environmental conditions play in habitat suitability helps to determine the regions in need of monitoring or protection for conservation of the species, particularly as climate change shifts suitable habitat. This study used three species distribution modeling algorithms, together with historical whale abundance data (1993–2009) and environmental covariate data, to build monthly ensemble models of past E. glacialis habitat suitability in the Gulf of Maine. The model was projected onto the year 2050 for a range of climate scenarios. Specifically, the distribution of the species was modeled using generalized additive models, boosted regression trees, and artificial neural networks, with environmental covariates that included sea surface temperature, bottom water temperature, bathymetry, a modeled Calanus finmarchicus habitat index, and chlorophyll. Year-2050 projections used downscaled climate anomaly fields from Representative Concentration Pathway 4.5 and 8.5. The relative contribution of each covariate changed seasonally, with an increase in the importance of bottom temperature and C. finmarchicus in the summer, when model performance was highest. A negative correlation was observed between model performance and sea surface temperature contribution. The 2050 projections indicated decreased habitat suitability across the Gulf of Maine in the period from July through October, with the exception of narrow bands along the Scotian Shelf. The results suggest that regions outside of the current areas of conservation focus may become increasingly important habitats for E. glacialis under future climate scenarios.
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