Scott D. Kraus

Evidence that ship noise increases stress in right whales

Baleen whales (Mysticeti) communicate using low-frequency acoustic signals. These long-wavelength sounds can be detected over hundreds of kilometres, potentially allowing contact over large distances. Low-frequency noise from large ships (20–200 Hz) overlaps acoustic signals used by baleen whales, and increased levels of underwater noise have been documented in areas with high shipping traffic. Reported responses of whales to increased noise include: habitat displacement, behavioural changes and alterations in the intensity, frequency and intervals of calls. However, it has been unclear whether exposure to noise results in physiological responses that may lead to significant consequences for individuals or populations. Here, we show that reduced ship traffic in the Bay of Fundy, Canada, following the events of 11 September 2001, resulted in a 6 dB decrease in underwater noise with a significant reduction below 150 Hz. This noise reduction was associated with decreased baseline levels of stress-related faecal hormone metabolites (glucocorticoids) in North Atlantic right whales (Eubalaena glacialis). This is the first evidence that exposure to low-frequency ship noise may be associated with chronic stress in whales, and has implications for all baleen whales in heavy ship traffic areas, and for recovery of this endangered right whale population.

Acoustic alarms reduce porpoise mortality

The most serious danger to dolphins and porpoises around the world is the threat from various forms of gill-net fishing. One potential way to reduce the number of deaths of marine mammals is the use of active acoustic alarms to warn animals about the presence of nets. Until now, acoustic alarms have not been tested in field experiments with sufficient statistical power. Here we describe a field experiment showing that acoustic alarms are effective at reducing the number of deaths of harbour porpoises (Phocoena phocoena) in sink gill-nets.

Satellite-monitored movements of the northern right whale

The northern right whale, Eubalaena glacialis, remains the most critically endangered of the large cetaceans despite international protection since 1936. We used satellite-monitored radiotags to identify the late-summer and fall habitat use patterns of right whales in the western North Atlantic. We tagged 9 whales in the Bay of Fundy (BOF) and successfully tracked them for a total of 13,910 km (x = 1,546 km) in 195 whale-tracking days (range 7-42 days each, x = 21.7 days). Individuals tracked for more than 12 consecutive days (N = 6 whales) left the BOF at least once and had higher average speeds (x = 3.5 km/hr) than those that stayed within the bay (x = 1.1 km/hr). Three of the tagged whales not only left the BOF, but traveled more than 2,000 km each before returning to the general tagging area. One adult female with a calf went to New Jersey and back to the BOF (3,761 km) in 42 days. Most locations were along bank edges, in basins or along the continental shelf. Eighty percent of locations were in water <182 m (100 fathoms [F]) deep. All of the tagged whales were located in or near shipping lanes. Right whale distribution coincided with areas intensively used by humans for fishing, shipping, and recreation. Individuals moved rapidly among areas previously identified as right whale habitat. Whale locations plotted on sea surface temperature (satellite infrared) images suggest that one whale spent time at the edge of a warm core ring and others spent extended periods in upwellings. Observations of whales surfacing with mud on their heads suggest that these whales fed near the BOF seafloor. Satellite telemetry is a useful means of tracking cetacean species that are difficult to view, move long distances, and might be too expensive to monitor by other means.

Overcoming the challenges of studying conservation physiology in large whales: a review of available methods

A description and comparison of the four major methods available for studying conservation physiology of large whales, namely analysis of faecal, respiratory vapour, and skin/blubber biopsy samples, and photographs.

Evaluating the effects of historic bottleneck events: an assessment of microsatellite variability in the endangered, North Atlantic right whale

Commercial exploitation reduced the North Atlantic right whale (Eubalaena glacialis) population from c. 12 000 in the 11th century to around 300 by the 21st century. We examine the effect of this population decline on levels of genetic variation at 16 microsatellite loci and contrast levels of variability to that in a closely related species (E. australis). Of the 13 loci developed from the E. glacialis genome, 100% were polymorphic in E. australis. In contrast, nine loci were polymorphic in E. glacialis and four were fixed. Both allelic diversity (A) and heterozygosity (H) were significantly lower in E. glacialis than E. australis (A = 3.2 ± 2.6 vs. A= 6.9 ± 3.3, P < 0.001; H= 0.31 ± 0.25 vs. H= 0.72 ± 0.23, P < 0.001, respectively). Bottleneck anlayses indicate that the population is in mutation‐drift equilibrium and that a genetic bottleneck did not occur during the most recent decline (18th–20th centuries). Nevertheless, low frequency alleles are relatively uncommon in E. glacialis, suggesting that genetic variability has been reduced in this population. Possible origins of low genetic variability are discussed, including the slow but continual erosion of alleles during the 800‐year period of decline.

Fishing Techniques to Reduce the Bycatch of Threatened Marine Animals

Methodology We attempted to document all available information on fishing techniques that have been used to reduce non-target wildlife species bycatch in world fisheries. Information on bycatch reduction methods is highly diffuse and for this review we consulted various sources including journal articles, unpublished government reports, and experts in the field. A number of reviews have examined bycatch reduction for particular fisheries (e.g., Broadhurst, 2000; Hall, 1995) or for wildlife groups within particular fisheries (e.g., Gilman et al., 2005), but the scope of this study is all commercial fishing methods and multiple wildlife groups. The decision to pursue a more comprehensive treatment was motivated by an interest in identifying bycatch reduction approaches that might find application in more than one fishing method, and to better appreciate the potential impacts on species or wildlife groups apart from the one targeted. Excluded from consideration were recreational fishing, target species bycatch (i.e., juvenile fish), and strategies for mitigating the consequences of ghost fishing, a serious and widespread form of bycatch in which fishing gear can continue to catch and kill animals after it has been lost, discarded, or abandoned by fishers. Depredation, or the predation of fishing bait or catch by non-target species, was considered in this review. This meant that some techniques mainly used in aquaculture operations became part of the final list. Generally, in categorizing bycatch reduction approaches the tendency was to be inclusive. For example, Turtle Excluder Devices and Sea Lion Excluder Devices were combined as one approach, under “excluders”, because they fundamentally work the same way. Both existing and proposed bycatch mitigation techniques were considered, and organized according to whether they represented an approach (1) intended to avert contact with a fishing operation and gear altogether, (2) intended to facilitate escape from temporary capture, or (3) that required release post-capture. For each technique we identified the fishing method (gillnet, surrounding net, trap/ pot, trawl, dredge, and hook-and-line) in which it was or could be used, and identified studies undertaken to evaluate its efficacy for various wildlife groups. The studies compiled consisted mainly of ones that directly reported on a scientific field trial as opposed to papers summarizing general findings or synthesizing responses from fishers. Occasionally, however, reports of lab studies or third-party papers reporting on original field research were included. Wildlife group classifications were selected somewhat arbitrarily and represent broad categories (sea birds, for example) in order to keep this review at a manageable scale. Certainly the number of categories could be M Introduction illions of dollars are spent each year in the research and development of fishing techniques to reduce unintended injuries and fatalities to non-target marine species that forms a major component of “bycatch.” The vast majority of this investment in conservation occurs in economically developed countries (principally the United States, Canada, Australia, and Europe) although the problem is global in scale. Taken as a whole, bycatch is one of the major threats to the survival of many endangered marine populations and species. This paper describes both proposed and existing fishing techniques for reducing nontarget species bycatch, and reviews their focus across different fisheries and wildlife groups. The intent of this inventory was to gain a better understanding of the range of techniques available and to highlight priorities for research and development. The bycatch reduction methods summarized in this paper are all intended to accommodate continued fishing of target species. Other strategies that can lead to lowered bycatch levels include fishing area closures, temporal closures, reductions in fishing effort, and cessation of fishing altogether. In some cases, applying one or more of these other measures may represent a better strategy for solving a particular bycatch challenge than altering fishing methods, though they often face resistance from the fishing industry.

Patterns of male reproductive success in a highly promiscuous whale species: the endangered North Atlantic right whale

Parentage analyses of baleen whales are rare, and although mating systems have been hypothesized for some species, little data on realized male reproductive success are available and the patterns of male reproductive success have remained elusive for most species. Here we combine over 20 years of photo‐identification data with high‐resolution genetic data for the majority of individual North Atlantic right whales to assess paternity in this endangered species. There was significant skew in male reproductive success compared to what would be expected if mating was random (P < 0.001). The difference was due to an excess of males assigned zero paternities, a deficiency of males assigned one paternity, and an excess of males assigned as fathers for multiple calves. The variance in male reproductive success was high relative to other aquatically mating marine mammals, but was low relative to mammals where the mating system is based on resource‐ and/or mate‐defence polygyny. These results are consistent with previous data suggesting that the right whale mating system represents one of the most intense examples of sperm competition in mammals, but that sperm competition on its own does not allow for the same degree of polygyny as systems where males can control access to resources and/or mates. The age distribution of assigned fathers was significantly biased towards older males (P < 0.05), with males not obtaining their first paternity until ~15 years of age, which is almost twice the average age of first fertilization in females (8 years), suggesting that mate competition is preventing younger males from reproducing. The uneven distribution of paternities results in a lower effective population size in this species that already has one of the lowest reported levels of genetic diversity, which may further inhibit reproductive success through mate incompatibility of genetically similar individuals.

Organochlorine levels in North Atlantic right whale (Eubalaena glacialis) blubber

Polychlorinated biphenyls (PCBs), total DDT (DDT+DDE+DDD), dieldrin, heptachlor epoxide, chlordanes, and hexachlorobenzene (HCB) were found in blubber biopsies from endangered North Atlantic right whales (Eubalaena glacialis) in the Bay of Fundy and on Browns-Baccaro Banks. Analyses included four sex and age class composite samples from 1988, and 21 individual samples from 1989. Generally, PCBs demonstrated the highest wet weight residue levels (up to 1.9 μg/g), followed by total DDT (DDT+DDE+DDD) (trace to 0.47 μg/g). Relatively low residue levels in adult females suggest that transmammary organochlorine (OC) residue transfer occurs during lactation. The actual blubber residue loads may have been under-estimated, because the samples were taken when the whales were depositing fat reserves and the samples may not have been representative of the remainder of the blubber.

Particulate hexavalent chromium is cytotoxic and genotoxic to the North Atlantic right whale (Eubalaena glacialis) lung and skin fibroblasts.

Hexavalent chromium compounds are present in the atmosphere and oceans and are established mutagens and carcinogens in human and terrestrial mammals. However, the adverse effects of these toxicants in marine mammals are uncertain. Previously, we reported that North Atlantic right whales, one of the most endangered great whales, have tissue chromium levels that are high, levels that may pose a risk to the whales health. Furthermore, the study suggested that inhalation may be an important exposure route. Exposure to chromium through inhalation is mainly because of particulate compounds. However, the toxicity of particulate chromium compounds in marine mammal cells is unknown. Accordingly, in this study, we tested the cytotoxic and genotoxic effects of particulate hexavalent chromium in primary cultured lung and skin fibroblasts from the endangered North Atlantic right whale. Cytotoxicity was measured by clonogenic survival assay, and genotoxicity was measured as production of chromosome aberrations. Particulate hexavalent chromium induced cytotoxicity and genotoxicity in a concentration‐dependent manner in both right whale lung and skin fibroblasts. Lung fibroblasts were more resistant to chromium cytotoxicity, but presented with more chromosome damage than skin fibroblasts. These data further support the hypothesis that chromium may be a health concern for the endangered North Atlantic right whale. Environ. Mol. Mutagen. 2009.

Using hierarchical bayes to understand movement, health, and survival in the endangered north atlantic right whale.

Body condition is an indicator of health, and it plays a key role in many vital processes for mammalian species. While evidence of individual body condition can be obtained, these observations provide just brief glimpses into the health state of the animal. An analytical framework is needed for understanding how health of animals changes over space and time.Through knowledge of individual health we can better understand the status of populations. This is particularly important in endangered species, where the consequences of disruption of critical biological functions can push groups of animals rapidly toward extinction. Here we built a state-space model that provides estimates of movement, health, and survival. We assimilated 30+ years of photographic evidence of body condition and three additional visual health parameters in individual North Atlantic right whales, together with survey data, to infer the true health status as it changes over space and time. We also included the effect of reproductive status and entanglement status on health. At the population level, we estimated differential movement patterns in males and females. At the individual level, we estimated the likely animal locations each month. We estimated the relationship between observed and latent health status. Observations of body condition, skin condition, cyamid infestation on the blowholes, and rake marks all provided measures of the true underlying health. The resulting time series of individual health highlight both normal variations in health status and how anthropogenic stressors can affect the health and, ultimately, the survival of individuals. This modeling approach provides information for monitoring of health in right whales, as well as a framework for integrating observational data at the level of individuals up through the health status of the population. This framework can be broadly applied to a variety of systems – terrestrial and marine – where sporadic observations of individuals exist.