Ground Off Research Articles

New Tudivasum Rosenberg & Petit, 1987 (Mollusca: Vasidae) from Queensland and the first report of sinistralism in that genus

Five new Tudivasum species are described from Queensland, Australia. Currently, only Tudivasum armigerum (Adams, 1856) and Tudivasum rasilistoma (Abbott, 1959) are recognized from the east Australian Coast, and are of comparable in size to the new species. An additional species, Tudivasum kurtzi (Macpherson, 1964) from northwestern Australia is included in this study as it is also of comparable size to the new species described here, although it is not found in the same biogeographical area. A coastal species, Tudivasum annettae n. sp. is described from Shoal Point, Central Queensland, where it has been found on intertidal sand/mud flats and near shore reefs. Tudivasum barbaracollinsae n. sp. is described from the far northern region of Queensland off the Cairns coastal trawler grounds. Tudivasum glendae n sp. is described from the northern Queensland trawling grounds off Townsville. Tudivasum amandacantamessae n. sp. is described from the central Queensland trawler grounds off Bowen. Tudivasum variabilis n. sp. is taken from the southern Queensland trawler grounds off Yeppoon. The first example of a sinistral Tudivasum from Australia is also presented.

Tracking nest-rescued green sea turtles in oceanic currents sheds light on eastern Caribbean “lost years”

Although sea turtles are well-studied charismatic marine species, little is known about the juvenile stage, especially the oceanic phase between hatching on their natal beaches and their adult lives. To collect data on these “lost years,” six juvenile green turtles were equipped with satellite tags, released from southwestern Dominica in the eastern Caribbean, and tracked for up to 3 months. Mapping turtle movement to ocean currents reveals that juvenile green turtles spent most of their travel time within the Caribbean Sea, passively riding the prevailing currents before actively directing themselves toward distant coastal waters. Half of the tagged turtles traveled to coastal foraging grounds off of Colombia and Venezuela, while one traveled north past Puerto Rico. These findings provide novel data for the movements of juvenile green turtles hatched in the Eastern Caribbean region.

The first aerial survey to estimate abundance of humpback whales (Megaptera novaeangliae) in the breeding ground off Brazil (Breeding Stock A)

In the Southern Hemisphere, humpback whales (Megaptera novaeangliae) were heavily exploited from both coastal stations and in pelagic waters in all major ocean basins. About 200,000 whales were taken after 1900, causing declines of populations to small percentages of their pre-exploitation levels. The study presented here aimed to investigate humpback whale abundance in the Brazilian coastal breeding ground, in order to provide information to support further analysis of the population recovery. Between 25 August and 2 September 2001, a fixed wing, flat window, aircraft was used to survey transect lines along the northern limit of Bahia State (12°10’S), to the southern limit of Espírito Santo State (20°42’S). All on-effort sightings were recorded and abundance was estimated according to standard distance sampling methodology (Burnham et al., 1980; Buckland et al., 1993). Group sizes of humpback whales ranged between 1-5 and the mean group size was 1.52 (±0.06). The model that best fitted the perpendicular distance data, based on the minimum Akaike Information Criterion, was the hazard rate model. The population size estimated using uncorrected data was 1,493 (CV=0.21) whales. Surface time was used to correct the estimates for gˆ(0), resulting in a correction factor of 0.67 (±0.15). The corrected analysis for each block and combined result, increased the population size estimate to 2,229 (CV=0.31) individuals. The data from this study could be used to identify new areas appropriate for whalewatching, to monitor the status and dynamics of the humpback whale population off the Brazilian coast and to provide information for the establishment of new protected areas.

A photographic match of a western gray whale between Sakhalin Island, Russia, and Honshu, Japan: the first link between the feeding ground and a migratory corridor

Between 2005 and 2007, four female western gray whales were accidentally entrapped and died in Japanese set nets while migrating along the Pacific coast of Honshu, Japan. Photographs of these animals were compared to a photo-identification catalogue of western gray whales from their feeding ground off Sakhalin Island, Russia, to look for matches of individuals between the two areas. Although useable quality photographs were available for only one of the four whales from Japan, a confirmed match was made to a whale photographed off Sakhalin Island. This match represents the first link between the feeding ground and a migratory corridor and highlights the importance of multinational research collaboration in the formation of range-wide conservation measures to protect this critically endangered population.

Bayesian estimation of the abundance of northern fur seals Callorhinus ursinus in the wintering and feeding ground off Sanriku on the Pacific coast of northern Japan

Bayesian estimation of the abundance of northern fur seals Callorhinus ursinus in the wintering and feeding ground off Sanriku on the Pacific coast of northern Japan

Chilean blue whales off Isla Grande de Chiloe, 2004-2010: distribution, site-fidelity and behaviour

A collaborative research program (the Alfaguara Project) has collected information on Chilean blue whales (Balaenoptera musculus) off Isla Grande de Chiloe, in southern Chile, through eight aerial and 85 marine surveys. A total of 363 individual blue whales was photo-identified from 2004 to 2010. Approximately 20% of all catalogued individuals were resighted within the same season and 31% were resighted between years. Recaptures of photo-identified individuals from other areas to the north and south of the main study area support the hypothesis that the feeding ground off southern Chile is extensive and dynamic. The high overall annual return and sighting rates highlight the waters off northwestern Isla de Chiloe and northern Los Lagos as the most important aggregation areas currently known for this species in Chile and one of the largest in the Southern Hemisphere. Observations on feeding and social behaviour also were recorded. These results provide important information on the conservation status of Chilean blue whales and highlight the necessity that long-term photographic identification research and line-transect surveys to monitor health conditions and population trends be continued off northwestern Isla de Chiloe. The high frequency of large vessels in the mouth of the Chacao Channel (along the north side of Isla de Chiloe) and the high number of blue whales in the area raises the possibility of vessel collisions. Therefore, it is necessary to develop and implement a conservation plan for these whales to address this and other potential threats.

Photo-identification comparison of humpback whale (Megaptera novaeangliae) flukes from Antarctic Area IV with fluke catalogues from East Africa, Western Australia and Eastern Australia

Early ‘Discovery mark’ data together with recent photo-identification, acoustic, genetic and satellite-radio tag data revealed linkages between humpback whales migrating from breeding grounds (C) off East Africa and the Area III feeding area, from Western Australian breeding grounds (D) and the Antarctic Area IV feeding area and the East Australian breeding grounds (E1) and Antarctic Area V feeding area. These data also revealed low levels of intermingling between (E1) and (D) humpback whales in the Antarctic Area IV feeding area consistent with these being separate populations. Greenpeace photographed the ventral tail flukes of 30 individual humpback whales in the Antarctic Area IV feeding area (70°E–130°E) from 2 to 9 January 2008, between 62°47’S and 64°14’S latitude and 80°00’E and 112°57’E longitude. Comparisons of the Antarctic Area IV Greenpeace fluke catalogue (n = 30) with existing reconciled fluke catalogues from East Africa (n = 842), Western Australia (n = 1,558) and Eastern Australia (n = 1,964), yielded no photo-identification matches. An analysis of the frequencies of whales seen and not seen in Antarctica, East Africa, Western Australia and Eastern Australia relative to the frequencies expected to have been seen and not seen, based on the estimated population sizes and the sizes of the catalogues, provided evidence that the Antarctic whales photographed are from a different population to the East African and East Australian populations. There was weak evidence supporting the hypothesis that the Antarctic whales are from the Western Australian population but insufficient data were available to determine a clear outcome. A comparison of the Antarctic Area IV Greenpeace catalogue (n = 30) with other existing African, Indian Ocean, Western and Eastern Australian and/or Antarctic catalogues, together with increased sampling across the humpback whale feeding season in Antarctica and along the Western and Eastern Australian coastline during their winter migration, is likely to provide further evidence of the migratory destination of these humpback whales. It will also add to our limited knowledge of the extent of population overlap within the Antarctic Area III, IV and V feeding areas.

Effect of Cr3C2 Content on the Microstructure and Wear Resistance of Fe3Al/Cr3C2 Composites

In this paper, an engine piston ring coating comprising composite material of Fe3Al and Cr3C2 mixed powder was prepared by laser cladding onto carbon structural steel. The microstructure and tribological properties of the cladding materials were investigated through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and wear tests. The influence mechanism of the Cr3C2 content in cladding powder was studied. During the process of wear, the soft Fe3Al/Fe2AlCr matrix is first ground off, and the hard Cr7C3 phase initially supports the abrasive surface before being worn away into hard particles, resulting in abrasive wear. With the increase in Cr3C2 content, the hardness of the cladding layer increases, the proportion of the Cr7C3 phase increases, and the morphology changes from a sparse network to a dense floccule. Of the cladding layers with different Cr3C2 content, the 15 wt.% Cr3C2 cladding layer had the lowest friction coefficient, and the 25 wt.% Cr3C2 cladding layer had the lowest wear rate. The low wear rate of the 25 wt.% Cr3C2 cladding layer can be attributed to the fact that adhesive wear does not easily occur and the fine microstructure of the strengthening phase, which facilitates better separation in the grinding surfaces.

Western gray whales on their summer feeding ground off Sakhalin Island in 2015: who is foraging where?

In the face of cumulative effects of oil and gas activities on the endangered western gray whale, informed management decisions rely on knowledge of gray whale spatial use patterns as a function of demographic group and prey energy. In particular, the gray whale foraging ground off Sakhalin Island consists of two distinct areas (nearshore and offshore) with the offshore feeding area exhibiting markedly high prey energy content. Based on photo-identification data collected from 2002 to 2015, we determined that gray whale use of the offshore feeding area increased with age. Pregnant females were more likely to be sighted only nearshore when nearshore prey energy and the proportion of nearshore energy from amphipods were higher. Likewise, females arriving with calves were less likely to be sighted offshore when the proportion of nearshore energy from amphipods was higher. Photo-identification effort in 2015 was increased substantially, with the intent of maximizing resighting data of individual whales to determine the relative proportion of different demographic groups utilizing the nearshore and offshore feeding areas. Comparing sighting data collected in 2015 with data from all previous years combined, mothers arriving with calves were sighted in the offshore feeding area earlier in 2015, with no evidence that they returned to forage nearshore later in the season. Other reproductive females constituted a higher proportion of the animals foraging nearshore prior to 2015, while juveniles were a higher proportion during 2015. Thus, the offshore feeding area is an important component of the gray whales’ annual life cycle, particularly if nearshore prey energy continues to decline, and offshore anthropogenic activities need to be monitored and addressed.

Bacterial and fungal pathogens in granulomatous lesions of Chelonia mydas in a significant foraging ground off southern Brazil.

The green sea turtle Chelonia mydas inhabit near-shore areas exposed to threatening anthropogenic activities. The granulomatous lesions in these animals may indicate infectious diseases that can be associated with environmental contamination and hazards to human health. This study aimed to characterize the granulomatous inflammation associated with bacterial and fungal infection in C. mydas off Paraná state. From September 2015 to February 2019, systematic monitoring was performed by the Santos Basin Beach Monitoring Project for sea turtles'carcasses recovery, necropsy, and cause of death diagnosis. The tissue samples were fixed in buffered formalin 10% for histochemical analysis and frozen for molecular analysis to fungi detection (Internal Transcribed Spacer region of the nuclear rDNA) and bacteria detection (16S ribosomal gene). From a total of 270 C. mydas, granulomatous lesions were observed in different organs of 63 (23.3%) individuals. The histological analysis indicated lesions in 94 organs, affecting most respiratory and digestive systems. Bacteria were identified in 25 animals, including an acid-fast bacteria detected in one animal, and fungi in 24 C. mydas. The fungi species included the genus Candida (Candida zeylanoides, n = 3), Yarrowia (Yarrowia lipolytica, n = 9; Yarrowia deformans, n=5; and Yarrowia divulgata, n = 1), and Cladosporium anthropophilum (n = 1). No species of bacteria was identified by molecular testing. All fungi species identified are saprobic, some are important to food and medical industries, but are also pathogens of humans and other animals. Therefore, long-term monitoring of these pathogens and the C. mydas health may indicate changes in environmental quality, possible zoonotic diseases, and their effects.

Long‐term interannual variability in larval dispersal and connectivity of the Norway lobster (Nephrops norvegicus) around Ireland: When supply‐side matters

AbstractDispersal of meroplankton larvae in the ocean is a key process which determines larval supply to areas of suitable habitat and enables connectivity between populations, particularly for nonmigratory species. Our objective was to use a biophysical larval transport model to create a time series (2000–2019) of larval retention, dispersal distance and connectivity estimates for the commercially important Norway lobster (Nephrops norvegicus) on mud grounds off Ireland. Where time series of population estimates were sufficiently long to conduct analysis, we also investigated if larval dispersal indices could be used to predict variations in adult density, after a lag period, hypothesising that this would only apply to grounds with consistently low larval supply. Grounds off Ireland had varying characteristics related to their ability to retain and exchange larvae which was influenced by the local hydrodynamic regime and spatial isolation from other grounds. Larval supply was consistently low on the Aran grounds to the west of Ireland, which have experienced abundance declines in the past. The time series of modelled larval dispersal indices at the Aran grounds was linked to empirical adult burrow densities with a 3‐year lag. Whereas the western Irish Sea, which has consistently high larval supply, showed no such relationship. Models can provide important larval recruitment information early in the life cycle for species of commercial or conservation importance.

Contribution to unravel variability in bowhead whale songs and better understand its ecological significance

Since the first studies on bowhead whale singing behaviour, song variations have been consistently reported. However, there has been little discussion regarding variability in bowhead whale singing display and its ecological significance. Unlike the better studied humpback whales, bowhead whales do not appear to share songs at population level, but several studies have reported song sharing within clusters of animals. Over the winter season 2013–2014, in an unstudied wintering ground off Northeast Greenland, 13 song groups sharing similar hierarchical structure and units were identified. Unit types were assessed through multidimensional maps, showing well separated clusters corresponding to manually labelled units, and revealing the presence of unit subtypes. Units presented contrasting levels of variability over their acoustic parameters, suggesting that bowhead whales keep consistency in some units while using a continuum in values of frequency, duration and modulation parameters for other unit types. Those findings emphasise the need to account for variability in song analysis to better understand the behavioural ecology of this endangered species. Additionally, shifting from song toward units or phrase-based analysis, as it has been suggested for humpback whales, offers the opportunity to identify and track similarities in songs over temporal and geographical scales relevant to population monitoring.

Ontogenetic changes in energy expenditure and resting behaviour of humpback whale mother–calf pairs examined using unmanned aerial vehicles

Context Baleen whale calves rapidly increase in size and improve locomotion abilities, while on their low-latitude breeding ground, allowing them to undertake a successful migration to high-latitude feeding grounds. Aims We investigated energy expenditure and resting behaviour of humpback whale (Megaptera novaeangliae) mother–calf pairs in regard to changes in calf length on an undisturbed breeding/resting ground off Exmouth Gulf, Western Australia. Methods Data were collected from August to October in 2018 and 2019 on lactating mothers that were predominantly resting on the surface with their calf. Focal follows on mother–calf pairs (n = 101) were conducted using an unmanned aerial vehicle to obtain detailed video of behaviours and respirations (23.7 h). Body length measurements of individual whales were calculated from aerial still frames. Key results Results on calves ranging in length from ~4–8 m demonstrated that calf respiration rate decreased with an increase in calf length and increased with presence of activity (P < 0.001). Calf inter-breath intervals became longer in duration with an increase in calf length (P < 0.01). Calf activity level and resting behaviour remained constant, with calves logging for 53% of the time their mothers were logging. Maternal respiration rate remained low and did not differ with respect to maternal or calf length. Conclusions Results highlighted the importance of resting grounds for energy preservation, which benefits the calves’ rapid growth before migration to polar waters. Implications Findings from the present largely undisturbed population serve as a baseline for understanding the impacts of anthropogenic disturbance on resting behaviour and energy expenditure in humpback whale mother–calf pairs globally.

Movements and behaviour of blue whales satellite tagged in an Australian upwelling system

Knowledge about the movement ecology of endangered species is needed to identify biologically important areas and the spatio-temporal scale of potential human impacts on species. Blue whales (Balaenoptera musculus) are endangered due to twentieth century whaling and currently threatened by human activities. In Australia, they feed in the Great Southern Australian Coastal Upwelling System (GSACUS) during the austral summer. We investigate their movements, occupancy, behaviour, and environmental drivers to inform conservation management. Thirteen whales were satellite tagged, biopsy sampled and photo-identified in 2015. All were genetically confirmed to be of the pygmy subspecies (B. m. brevicauda). In the GSACUS, whales spent most of their time over the continental shelf and likely foraging in association with several seascape variables (sea surface temperature variability, depth, wind speed, sea surface height anomaly, and chlorophyll a). When whales left the region, they migrated west and then north along the Australian coast until they reached West Timor and Indonesia, where their movements indicated breeding or foraging behaviour. These results highlight the importance of the GSACUS as a foraging ground for pygmy blue whales inhabiting the eastern Indian Ocean and indicate the whales’ migratory route to proposed breeding grounds off Indonesia. Information about the spatio-temporal scale of potential human impacts can now be used to protect this little-known subspecies of blue whale.

Behavioural Responses of Humpback Whales (Megaptera novaeangliae) to Two Acoustic Deterrent Devices in a Northern Feeding Ground off Iceland

Behavioural Responses of Humpback Whales (Megaptera novaeangliae) to Two Acoustic Deterrent Devices in a Northern Feeding Ground off Iceland

Changing patterns of habitat use by southern right whales (Eubalaena australis) on their nursery ground at Península Valdés, Argentina, and in their long-range movements

Southern right whales (Eubalaena australis) have been studied on their nursery ground at Península Valdés, Argentina, every year since 1970. Since 1990, 1,208 individuals have been identified from photographs taken during annual aerial surveys; 618 whales were seen in two or more years. Patterns of habitat use have changed during the study in ways which suggest that right whales may be capable of substantial behavioral and ecological flexibility. One male and three females from Península Valdés have been sighted on other nursery grounds (Tristan da Cunha and southern Brazil). Three individuals from Península Valdés were sighted on feeding grounds off Shag Rocks and South Georgia. Some right whales from Península Valdés showed carbon and nitrogen isotope ratios very similar to those seen in right whales off South Africa, while others showed distinctive isotope ratios indicating that they fed in a different area. Whales of all ages and both sexes moved frequently between three major regions of concentration on the Península Valdés nursery ground. Subadults and adult females with calves were resighted at higher rates than adult males and females in non-calf years. Changes in the geographic distribution of whales at the Península include: (1) abandonment of a major region of concentration; (2) establishment of a nursery area adjacent to thecentre of a growing whalewatching industry; and (3) small-scale shifts in distribution, possibly in response to natural and human disturbances.

Nonlinear dynamics and noise actuated by the cycle of gene inactivation in stochastic transcription

Gene transcription is a stochastic process with random switching between gene off and on states. In this paper, we established a cycle of gene inactivation consisting of two off states. External signals trigger the random transition from the “ground off” (I1) state to the “excited off” (I2) state, which in turn either jumps forward to the on state or recycles back to I1 state. By integrating inactivation cycle with mRNA birth and death processes, we focus on how the recycling efficiency λ21 from I2 to I1 influences dynamical mRNA mean m(t) and the stationary noise strength Φ*. We first reveal a bidirectional regulation of λ21 on m(t): Increase of λ21 can either induce the monotonic dynamics of m(t) to the non-monotonic behavior or suppress non-monotonic dynamics to monotonicity for m(t). For Φ*, we observe two regulation scenarios that the increase of λ21 can significantly up-regulate Φ* and weaken the non-monotonic dependence of Φ* on the other parameter rates. The robustness of these results is further tested against experimental data in E.coli, yeast and mammalian cells. Taken together, we show that the cycle of gene inactivation can provide a more comprehensive mechanism on gene regulation.

Special Report: Racism and Inequities in Health Care for Black Americans

<i>Special Report:</i> Racism and Inequities in Health Care for Black Americans

Vessel noise levels drive behavioural responses of humpback whales with implications for whale-watching.

Disturbance from whale-watching can cause significant behavioural changes with fitness consequences for targeted whale populations. However, the sensory stimuli triggering these responses are unknown, preventing effective mitigation. Here, we test the hypothesis that vessel noise level is a driver of disturbance, using humpback whales (Megaptera novaeangliae) as a model species. We conducted controlled exposure experiments (n = 42) on resting mother-calf pairs on a resting ground off Australia, by simulating whale-watch scenarios with a research vessel (range 100 m, speed 1.5 knts) playing back vessel noise at control/low (124/148 dB), medium (160 dB) or high (172 dB) low frequency-weighted source levels (re 1 μPa RMS@1 m). Compared to control/low treatments, during high noise playbacks the mother's proportion of time resting decreased by 30%, respiration rate doubled and swim speed increased by 37%. We therefore conclude that vessel noise is an adequate driver of behavioural disturbance in whales and that regulations to mitigate the impact of whale-watching should include noise emission standards.

Marine plastic litter in certain trawl grounds along the peninsular coasts of India

Non-biodegradable marine debris such as derelict fishing gears and their parts, polythene covers, carry bags, synthetic packaging materials etc., cause serious damages to the benthic ecosystem including the marine biota. We report here the monthly variation in the marine plastic litter (MPL) and its relative percentage to the quantity of fish caught from the trawling grounds off Cochin, Ratnagiri, Mumbai and Veraval along the west coast as well as Visakhapatnam from the east coast of India. The mean values of MPL from the fishing grounds registered the maximum of 55.2 ± 16.52 kg/km2 off Veraval and the minimum of 2.11 ± 0.55 kg/km2 off Visakhapatnam, registering a national average of 10.95 ± 3.05 kg/km2. The relative percentage of MPL over the fish catch remained highest (3.83%) at Veraval and lowest from Visakhapatnam (0.33%) while, the national average was 1.89 ± 0.28. Monsoon season registered maximum MPL in the fishing grounds of all the coastal regions we studied. Depth of the trawling grounds also influenced the quantity of MPL that 20 m depth registered quantity (24.25 ± 9.16 kg/km2) and the overall mean at 10 m and 40 m depth zone are significantly different from that of 20 m. The database created through this study are discussed in the light of increasing deleterious effects of plastic pollution in the active fishing areas in coastal region and the urgent need to save the sea for sustainable use of its resources.