scholarly journals Beaked whales demonstrate a marked acoustic response to the use of shipboard echosounders

2017 ◽  
Vol 4 (12) ◽  
pp. 170940 ◽  
Author(s):  
Danielle Cholewiak ◽  
Annamaria I. DeAngelis ◽  
Debra Palka ◽  
Peter J. Corkeron ◽  
Sofie M. Van Parijs
Keyword(s):  
Linear Models ◽  
Anthropogenic Impacts ◽  
Benthic Habitat ◽  
Acoustic Response ◽  
Marine Animals ◽  
Sea State ◽  
Detection Rates ◽  
Ecosystem Studies ◽  
Primary Driver ◽  
Beaked Whales

The use of commercial echosounders for scientific and industrial purposes is steadily increasing. In addition to traditional navigational and fisheries uses, commercial sonars are used extensively for oceanographic research, benthic habitat mapping, geophysical exploration, and ecosystem studies. Little is known about the effects of these acoustic sources on marine animals, though several studies have already demonstrated behavioural responses of cetaceans to shipboard echosounders. Some species of cetaceans are known to be particularly sensitive to acoustic disturbance, including beaked whales. In 2011 and 2013, we conducted cetacean assessment surveys in the western North Atlantic in which a suite of Simrad EK60 echosounders was used to characterize the distribution of prey along survey tracklines. Echosounders were alternated daily between active and passive mode, to determine whether their use affected visual and acoustic detection rates of beaked whales. A total of 256 groups of beaked whales were sighted, and 118 definitive acoustic detections were recorded. Regression analyses using generalized linear models (GLM) found that sea state and region were primary factors in determining visual sighting rates, while echosounder state was the primary driver for acoustic detections, with significantly fewer detections (only 3%) occurring when echosounders were active. These results indicate that beaked whales both detect and change their behaviour in response to commercial echosounders. The mechanism of this response is unknown, but could indicate interruption of foraging activity or vessel avoidance, with potential implications for management and mitigation of anthropogenic impacts.

scholarly journals MAPPING OF THE SEAGRASS COVER ALONG THE MEDITERRANEAN COAST OF TURKEY USING LANDSAT 8 OLI IMAGES

2016 ◽  
Vol XLI-B8 ◽  
pp. 1103-1105 ◽  
Author(s):  
T. Bakirman ◽  
M. U. Gumusay ◽  
I. Tuney
Keyword(s):  
Accuracy Assessment ◽  
Mediterranean Coast ◽  
Environmental Data ◽  
Benthic Habitat ◽  
Landsat 8 ◽  
Landsat 8 Oli ◽  
Carbon Dioxide Absorption ◽  
Landsat Images ◽  
Marine Animals ◽  
Seagrass Cover

Benthic habitat is defined as ecological environment where marine animals, plants and other organisms live in. Benthic habitat mapping is defined as plotting the distribution and extent of habitats to create a map with complete coverage of the seabed showing distinct boundaries separating adjacent habitats or the use of spatially continuous environmental data sets to represent and predict biological patterns on the seafloor. Seagrass is an essential endemic marine species that prevents coast erosion and regulates carbon dioxide absorption in both undersea and atmosphere. Fishing, mining, pollution and other human activities cause serious damage to seabed ecosystems and reduce benthic biodiversity. According to the latest studies, only 5–10% of the seafloor is mapped, therefore it is not possible to manage resources effectively, protect ecologically important areas. In this study, it is aimed to map seagrass cover using Landsat 8 OLI images in the northern part of Mediterranean coast of Turkey. After pre-processing (e.g. radiometric, atmospheric, water depth correction) of Landsat images, coverage maps are produced with supervised classification using in-situ data which are underwater photos and videos. Result maps and accuracy assessment are presented and discussed.

scholarly journals Regional Assessment of the Conservation Status of Snubfin Dolphins (Orcaella heinsohni) in the Kimberley Region, Western Australia

2021 ◽  
Vol 7 ◽  
Author(s):  
Phil J. Bouchet ◽  
Deborah Thiele ◽  
Sarah A. Marley ◽  
Kelly Waples ◽  
Frank Weisenberger ◽  
...  
Keyword(s):  
Western Australia ◽  
Conservation Status ◽  
Regional Scale ◽  
Indigenous Communities ◽  
Multiple Sources ◽  
Marine Animals ◽  
Cetacean Species ◽  
Detection Rates ◽  
Area Of Occupancy ◽  
Kernel Approach

Implementing conservation measures for data-limited species is a fundamental challenge for wildlife managers and policy-makers, and proves difficult for cryptic marine animals occurring in naturally low numbers across remote seascapes. There is currently scant information on the abundance and habitat preferences of Australian snubfin dolphins (Orcaella heinsohni) throughout much of their geographical range, and especially within the Kimberley region of northern Western Australia. Such knowledge gaps curtail rigorous threat assessments on both local and regional scales. To address this and assist future conservation listings, we built the first comprehensive catalog of snubfin dolphin sightings for the Kimberley. We used these data to estimate the species’ extent of occurrence (EOO) and area of occupancy (AOO) along the region’s 7,000 km coastline, following a simple Bootstrap bivariate kernel approach to combine datasets of varying quality and quantify uncertainty. Our catalog consists of 1,597 visual detections of snubfin dolphins made over a period of 17 years (2004–2020) and collated from multiple sources, including online biodiversity repositories, peer-reviewed scientific articles, citizen science programs, as well as dedicated marine wildlife surveys with local Indigenous communities and Ranger groups. Snubfin dolphins were consistently encountered in shallow waters (<21 m depth) close to (<15 km) freshwater inputs, with high detection rates in known hotspots (e.g., Roebuck Bay, Cygnet Bay) as well as in coastal habitats suspected to be suitable (e.g., Prince Regent River and surrounds, King Sound, Doubtful Bay, Napier Broome Bay and the upper Cambridge Gulf). Bootstrap estimates of EOO and AOO were 38,300 (95% CI: 25,451–42,437) km2 and 700 (656–736) km2 respectively, suggesting that snubfin dolphins in the Kimberley are likely Vulnerable under IUCN criteria B2 at a regional scale, in keeping with their global classification. Our study offers insights into the distribution of a vulnerable coastal cetacean species and demonstrates the value of integrating multiple data sources for informing conservation assessments in the face of uncertainty.

scholarly journals Multispectral Multibeam Echo Sounder Backscatter as a Tool for Improved Seafloor Characterization

Geosciences ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 126 ◽  
Author(s):  
Craig Brown ◽  
Jonathan Beaudoin ◽  
Mike Brissette ◽  
Vicki Gazzola
Keyword(s):  
Habitat Mapping ◽  
Benthic Habitat ◽  
Underwater Video ◽  
Acoustic Response ◽  
Acoustic Measurements ◽  
Seabed Classification ◽  
Seafloor Characterization ◽  
Ground Validation ◽  
Dredge Spoil ◽  
Mapping Systems

The establishment of multibeam echosounders (MBES), as a mainstream tool in ocean mapping, has facilitated integrative approaches towards nautical charting, benthic habitat mapping, and seafloor geotechnical surveys. The combined acoustic response of the seabed and the subsurface can vary with MBES operating frequency. At worst, this can make for difficulties in merging the results from different mapping systems or mapping campaigns. However, at best, having observations of the same seafloor at different acoustic wavelengths allows for increased discriminatory power in seabed classification and characterization efforts. Here, we present the results from trials of a multispectral multibeam system (R2Sonic 2026 MBES, manufactured by R2Sonic, LLC, Austin, TX, USA) in the Bedford Basin, Nova Scotia. In this system, the frequency can be modified on a ping-by-ping basis, which can provide multi-spectral acoustic measurements with a single pass of the survey platform. The surveys were conducted at three operating frequencies (100, 200, and 400 kHz), and the resulting backscatter mosaics revealed differences in parts of the survey area between the frequencies. Ground validation surveys using a combination of underwater video transects and benthic grab and core sampling confirmed that these differences were due to coarse, dredge spoil material underlying a surface cover of mud. These innovations offer tremendous potential for application in the area of seafloor geological and benthic habitat mapping.

scholarly journals Limnological Characteristics and Diatom Dominants in Lakes of Northeastern Poland

Diversity ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 374
Author(s):  
Monika Eliasz-Kowalska ◽  
Agata Z. Wojtal
Keyword(s):  
Human Impact ◽  
Linear Models ◽  
Human Impacts ◽  
Anthropogenic Impacts ◽  
Hierarchical Cluster ◽  
P Value ◽  
Diatom Assemblages ◽  
Large Area ◽  
Mean Values ◽  
Dominance Structure

Determination of the relationships between environmental factors and diatom assemblages is usually made for several hundred lakes spread over a large area. However, the analysis of several lakes located near Lake Wigry also gives interesting results. Lakes in Wigry National Park (Poland) with broad similarity of geological origin show clear limnological, physical, and chemical differences. Here, we report on an investigation into how these dissimilarities influence diatom assemblages. Hierarchical Cluster Analysis showed that the studied lakes can be divided into three groups: (1) disharmonic, (2) harmonious with greater human impact on the environment, and (3) harmonious with a more limited human impact. The harmonious lakes could be divided into two groups that are mainly in line with the contents of the chloride and sulfates ions taken as indicative of human impacts on the environment. Overall, the three groups had different dominance structures, as reference to the Dominance Index (DI) made clear (mean values being: (1) −70.54%, (2) −72%, and (3) −54.58%, Generalized Linear Models with the categorical independent variable (group) showed significant differences between groups (for 1–3, 2–3) p value < 0.05). Lakes impacted by anthropopressure and disharmonic ones had the strongest dominance structure. More broadly, DI differences between the groups are consistent with the Species Pool Hypothesis (SPH), while studied differences can be said to result from natural geological dissimilarities, as well as disparate anthropogenic impacts.

scholarly journals Precision in bycatch estimates: the case of tuna purse-seine fisheries in the Indian Ocean

2012 ◽  
Vol 69 (8) ◽  
pp. 1501-1510 ◽  
Author(s):  
Monin J. Amandè ◽  
Emmanuel Chassot ◽  
Pierre Chavance ◽  
Hilario Murua ◽  
Alicia Delgado de Molina ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Linear Models ◽  
Purse Seine ◽  
Reliable Estimate ◽  
Routine Practice ◽  
Marine Animals ◽  
Trade Offs ◽  
The Indian Ocean ◽  
Current Sampling ◽  
Tropical Tuna

Abstract Amandè, M. J., Chassot, E., Chavance, P., Murua, H., Delgado de Molina, A., and Bez, N. 2012. Precision in bycatch estimates: the case of tuna purse-seine fisheries in the Indian Ocean. – ICES Journal of Marine Science, 69: . Estimating bycatch, i.e. the incidental catch of non-target marine animals and undersized individuals of target species, by raising observer data to the whole fishery is routine practice. The annual bycatch of the European tropical tuna purse-seine fishery over the period 2003–2009 was estimated at 11 590 t [95% confidence interval: (8165–15 818 t)], corresponding to 4.7% of the tuna landings. An analysis of the variability in the precision of this estimate, based on generalized linear models and Monte Carlo simulations, showed that the current sampling coverage of the tropical tuna fishery observer programme, which is 4.6% of the fishing trips, resulted in large uncertainties in bycatch estimates by species, i.e. none of the estimates have a relative root mean square error smaller than 50%. Although the overall magnitude of bycatch of the fishery appeared to be small, the current sampling coverage was insufficient to give any reliable estimate for low-occurring species, such as marine turtles, some oceanic pelagic sharks, and some billfishes. Increasing the sampling coverage would likely improve bycatch estimates. Simulation outputs were produced to help define (i) trade-offs between the priority species to be monitored, (ii) the estimation precision, (iii) expected accuracy, and (iv) the associated sampling costs.

scholarly journals Ichthyofauna of the Mata de Itamacaoca, an urban protected area from the upper Munim River basin, Northern Brazilian Cerrado

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Elioenai da Silva Oliveira ◽  
Erick Cristofore Guimarães ◽  
Pâmella Silva de Brito ◽  
Lucas de Oliveira Vieira ◽  
Rafael Ferreira de Oliveira ◽  
...  
Keyword(s):  
Species Richness ◽  
River Basin ◽  
Fish Species ◽  
Fish Community ◽  
Linear Models ◽  
Anthropogenic Impacts ◽  
Sampling Site ◽  
Abundant Species ◽  
Diversity Indices ◽  
Alien Invasive Species

Abstract: The Munim River basin is one of the main river drainages of the Hydrological unit Maranhão, but there are few published studies which focus on ichthyological surveys and taxonomic work within this basin. The present study aims to provide a fish species inventory of the Mata da Itamacaoca, one of the few urban protected areas from the upper Munim River basin, comparing the ichthyofauna with other lists by conducted at the upper Munim River basin. A total of 42 collection expeditions were conducted, the sampling was conducted at five collecting sites distributed within the boundaries of Mata de Itamacaoca, upper Munim River basin. Diversity indices were calculated and generalised linear models (GLMs) were employed to assess differences in species richness, diversity and evenness depending on season and location in relation to the reservoir dam wall. In order to visualize fish community differences, non-metric multidimensional scaling (nMDS) and a one-way PERMANOVA was used to understand whether factors of site, season and location to the dam wall had an effect on fish community compositions. A total of six orders, 13 families, and 23 fish species were found, and the order with the highest species richness, considering all reaches, was Characiformes followed by Cichliformes. The most abundant species was Nannostomus beckfordi, while Pimelodella parnahybae and Hoplerythrinus unitaeniatus were the rarer species sampled. There were no alien invasive species collected within the study area. Species richness was significantly higher below the dam wall, but there were no other significant differences in diversity indices with regards to season or location. Fish community composition was significantly different above and below the dam wall and was significantly affected by sampling site. Season did not have an effect on fish community. This study corroborates other studies conducted in the Unidade Hidrológica Maranhão sensu Hubbert and Renno (2006), that the ichthyofaunal composition and taxonomy of species within this region face major data deficits, anthropogenic impacts, this study may be a baseline for comparing similar environments throughout the region.

scholarly journals Using passive acoustic monitoring to document the distribution of beaked whale species in the western North Atlantic Ocean

2017 ◽  
Vol 74 (12) ◽  
pp. 2098-2109 ◽  
Author(s):  
Joy E. Stanistreet ◽  
Douglas P. Nowacek ◽  
Simone Baumann-Pickering ◽  
Joel T. Bell ◽  
Danielle M. Cholewiak ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Anthropogenic Impacts ◽  
Acoustic Monitoring ◽  
Latitudinal Gradients ◽  
Beaked Whale ◽  
Passive Acoustic Monitoring ◽  
Beaked Whales ◽  
Passive Acoustic

Little is known about the ecology of many beaked whale species, despite concerns raised by mass strandings linked to certain sources of anthropogenic noise. Here, we used passive acoustic monitoring to examine spatial and temporal patterns in beaked whale occurrence at six locations along the continental slope in the western North Atlantic Ocean. We analyzed 2642 days of recordings collected between 2011 and 2015, and identified echolocation signals from northern bottlenose whales (Hyperoodon ampullatus), Cuvier’s (Ziphius cavirostris), Sowerby’s (Mesoplodon bidens), Gervais’, (Mesoplodon europaeus), and Blainville’s (Mesoplodon densirostris) beaked whales, and one signal type of unknown origin. We recorded multiple species at each site, with detections generally occurring year-round, and observed latitudinal gradients and site-specific variation in relative species occurrence. Notably, we regularly detected Cuvier’s beaked whales in a region where they have not been commonly observed, and discovered potential habitat partitioning among Cuvier’s and Gervais’ beaked whales within their overlapping ranges. This information on the distribution and seasonal occurrence of North Atlantic beaked whale species offers new insight into patterns of habitat use, and provides a year-round baseline from which to assess potential anthropogenic impacts.

Validating acoustic monitors for marine animals: Field experience with beaked whales and digital acoustic monitors (DMONs).

2009 ◽  
Vol 125 (4) ◽  
pp. 2587-2587
Author(s):  
Mark Johnson ◽  
Tom Hurst ◽  
Anton Arias ◽  
Natacha Aguilar de Soto
Keyword(s):  
Field Experience ◽  
Marine Animals ◽  
Beaked Whales

scholarly journals Ontogenetic Habitat Use and Density of the Green Lizard (Lacerta bilineata) in Contrasted Landscapes in France and Italy

Conservation ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 1-16
Author(s):  
Lorenzo Rugiero ◽  
Massimo Capula ◽  
Massimiliano Di Vittorio ◽  
Daniele Dendi ◽  
Roger Meek ◽  
...  
Keyword(s):  
Population Ecology ◽  
Linear Models ◽  
Anthropogenic Impacts ◽  
Central Italy ◽  
Temporal Stability ◽  
Habitat Modification ◽  
Italian Population ◽  
Lizard Species ◽  
Contingency Table Analysis ◽  
Fragmented Habitat

Habitat modification is a major factor in the decline of reptile populations. The degree of the decline has been shown to be directly related to the intensity of habitat modification. Farming practices and urbanization are just two of the factors involved indicating that the development of practices that minimize or cancel anthropogenic impacts is urgently needed to prevent further declines. This requires knowledge of population ecology of reptiles in both disturbed and pristine habitats. In this paper, we describe aspects of green lizard (Lacerta bilineata) population ecology in a forest–pasture relatively pristine mosaic habitat in central Italy and a fragmented habitat in western France. In Italy, habitat niche overlap was very high between males and females but very low between males and juveniles. For male and female abundances, general linear models showed that the adult abundances increased with the increase of Rubus bushes, whereas juvenile abundance increased with the increase of Spartium bushes. Contingency table analysis showed that juveniles were also much more frequently observed in grasslands than adults of either sexes. The observed ontogenetic structural niche pattern was likely due to intraspecific competition avoidance, competition interference, and cannibalism. The persistence of the same patterns across years demonstrates a temporal stability of the ontogenetic structural niche pattern. Over the length of the study period, population densities were stable in the Italian population, but densities were much higher by around five times in the hedgerow in the fragmented habitat in France. In the hedgerow, monthly lizard presence was uneven, with the greatest number of sightings in June and July. Overall, our study provided no support for the notion that lizard abundance/density should be lower in modified compared to unmodified habitats, and clearly revealed that a careful management of the hedgerows is crucial for the conservation of this lizard species in agro-forest ecosystems.

scholarly journals Hydrological modeling of freshwater discharge into Hudson Bay using HYPE

Elem Sci Anth ◽  
2020 ◽  
Vol 8 ◽  
Author(s):  
Tricia A. Stadnyk ◽  
Matthew K. MacDonald ◽  
Andrew Tefs ◽  
Stephen J. Déry ◽  
Kristina Koenig ◽  
...  
Keyword(s):  
Hydrological Modeling ◽  
Drainage Basin ◽  
Anthropogenic Impacts ◽  
Frozen Soil ◽  
Freshwater Discharge ◽  
Regulated River ◽  
The Arctic ◽  
Hudson Bay ◽  
Ecosystem Studies ◽  
Climate Interactions

This study details the enhancement and calibration of the Arctic implementation of the HYdrological Predictions for the Environment (HYPE) hydrological model established for the BaySys group of projects to produce freshwater discharge scenarios for the Hudson Bay Drainage Basin (HBDB). The challenge in producing estimates of freshwater discharge for the HBDB is that it spans over a third of Canada’s continental landmass and is 40% ungauged. Scenarios for BaySys require the separation between human and climate interactions, specifically the separation of regulated river discharge from a natural, climate-driven response. We present three key improvements to the modelling system required to support the identification of natural from anthropogenic impacts: representation of prairie disconnected landscapes (i.e., non-contributing areas), a method to generalize lake storage-discharge parameters across large regions, and frozen soil modifications. Additionally, a unique approach to account for irregular hydrometric gauge density across the basins during model calibration is presented that avoids overfitting parameters to the densely gauged southern regions. We summarize our methodologies used to facilitate improved separation of human and climate driven impacts to streamflow within the basin and outline the baseline discharge simulations used for the BaySys group of projects. Challenges remain for modeling the most northern reaches of the basin, and in the lake-dominated watersheds. The techniques presented in this work, particularly the lake and flow signature clusters, may be applied to other high latitude, ungauged Arctic basins. Discharge simulations are subsequently used as input data for oceanographic, biogeochemical, and ecosystem studies across the HBDB.

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