Pacific herring respond to simulated odontocete echolocation sounds

2002 ◽  
Vol 59 (3) ◽  
pp. 542-553 ◽  
Author(s):  
Ben Wilson ◽  
Lawrence M Dill
Keyword(s):  
Water Column ◽  
Swimming Speed ◽  
High Frequency ◽  
Marine Mammals ◽  
Major Part ◽  
Pacific Herring ◽  
Selective Forces ◽  
Sea Cage ◽  
Clupeoid Fish ◽  
Behavioural Repertoire

There has been a long-running debate as to if and how clupeoid fish, such as herring (Clupea sp.), respond to anthropogenic sound. Anatomical and physiological investigations have shown that members of the clupeoid suborder have highly developed hearing extending into ultrasonic frequencies and behavioural studies suggest that they respond to many sounds. However, only recently have the selective forces that have driven the evolution of this keen sense and behavioural repertoire played a major part in the debate. One explanation is the adaptation to predation from echolocating cetaceans. In this study, we investigate the responses of adult Pacific herring (Clupea pallasii) to broadband biosonar-type sounds with high-frequency similarities to those produced by odontocete cetaceans. Exposures to these sounds in an indoor tank and sea cage caused feeding fish to cease, drop in the water column, and begin to school actively. Fish already schooling dropped in the water column and increased their swimming speed. Exposures to electronic silence and an acoustic deterrent device for marine mammals did not elicit such responses. We discuss the potential suitability of the observed manoeuvres for avoidance of foraging odontocetes and consider their relevance for human-related fishing activities.

scholarly journals Rapid observations of ocean dynamics and stratification along a steep island coast during Hurricane María

2021 ◽  
Vol 7 (20) ◽  
pp. eabf1552
Author(s):  
Olivia M. Cheriton ◽  
Curt D. Storlazzi ◽  
Kurt J. Rosenberger ◽  
Clark E. Sherman ◽  
Wilford E. Schmidt
Keyword(s):  
Puerto Rico ◽  
Water Column ◽  
High Frequency ◽  
Coastal Communities ◽  
Ocean Dynamics ◽  
Sea Surface ◽  
Hurricane Intensity ◽  
Island Coast ◽  
New Framework ◽  
Insular Shelf

Hurricanes are extreme storms that affect coastal communities, but the linkages between hurricane forcing and ocean dynamics remain poorly understood. Here, we present full water column observations at unprecedented resolution from the southwest Puerto Rico insular shelf and slope during Hurricane María, representing a rare set of high-frequency, subsurface, oceanographic observations collected along an island margin during a hurricane. The shelf geometry and orientation relative to the storm acted to stabilize and strengthen stratification. This maintained elevated sea-surface temperatures (SSTs) throughout the storm and led to an estimated 65% greater potential hurricane intensity contribution at this site before eye passage. Coastal cooling did not occur until 11 hours after the eye passage. Our findings present a new framework for how hurricane interaction with insular island margins may generate baroclinic processes that maintain elevated SSTs, thus potentially providing increased energy for the storm.

scholarly journals Selective sweep near the In(2L)t inversion breakpoint in an African population of Drosophila melanogaster

2000 ◽  
Vol 76 (2) ◽  
pp. 149-158 ◽  
Author(s):  
FRANTZ DEPAULIS ◽  
LIONEL BRAZIER ◽  
SYLVAIN MOUSSET ◽  
ANNE TURBE ◽  
MICHEL VEUILLE
Keyword(s):  
Drosophila Melanogaster ◽  
High Frequency ◽  
Selection Effect ◽  
West African ◽  
African Population ◽  
Inversion Breakpoint ◽  
Major Haplotype ◽  
Selective Forces ◽  
Significant Deficit ◽  
Proximal Breakpoint

Chromosomal inversions largely inhibit recombination and may be associated with selective forces, such as hitch-hiking effects: the effect of positive selection on linked loci. A West African population of Drosophila melanogaster showed a high frequency (0·61) of the In(2L)t inversion. Departure from neutrality statistically associated with the inversion polymorphism was previously recorded at Su(H), a locus distant from the proximal breakpoint of the inversion. These results were consistent with hitch-hiking effects with recombination. The present sequence polymorphism survey involves a 1 kb fragment of the Vha68-1 locus located closer to the proximal breakpoint of the inversion. It shows a significant deficit of polymorphism with respect to divergence when compared with other loci studied in the same population, thus suggesting selective effects. Only 11 polymorphic sites are present in a sample of 20 chromosomes and these sites present a significant excess of rare-frequency variants. The major haplotype shows an unexpectedly high frequency. Our estimate of the background selection effect is not sufficient to account for the observed reduction of polymorphism. Intraspecific variation is structured between inverted and standard chromosomes; there are no shared polymorphisms but also no fixed differences between them. This pattern, together with that found on other loci previously studied near this inversion breakpoint, suggests hitch-hiking effects enhanced by the inversion.

High‐frequency Acoustic Recording Package (HARP) for long‐term monitoring of marine mammals

2006 ◽  
Vol 120 (5) ◽  
pp. 3015-3015
Author(s):  
Sean M. Wiggins ◽  
Chris Garsha ◽  
Greg Campbell ◽  
John A. Hildebrand
Keyword(s):  
High Frequency ◽  
Marine Mammals ◽  
Long Term Monitoring ◽  
Acoustic Recording ◽  
Term Monitoring

Economic Factors in Catch Fluctuations

1955 ◽  
Vol 12 (1) ◽  
pp. 85-92
Author(s):  
H. Scott Gordon
Keyword(s):  
Statistical Analysis ◽  
Major Part ◽  
Economic Factors ◽  
Pacific Herring ◽  
Atlantic Herring ◽  
Pacific Halibut ◽  
Correlation Methods ◽  
Commercial Species

Correlation methods were employed in a statistical analysis of the relation between catch fluctuations and economic factors for the principal Canadian commercial species of the Atlantic and Pacific coasts. The results indicate that the major part of catch fluctuations are ascribable to economic factors in the cases of Atlantic herring, "sardines", and cod (tentative), and Pacific herring. Economic factors appear to have had no significant effect on the catches of Atlanta lobsters and Pacific halibut and salmon.

Faecal testosterone concentrations and the acoustic behaviour of two captive male Australian fur seals

2009 ◽  
Vol 31 (2) ◽  
pp. 117 ◽  
Author(s):  
Joy S. Tripovich ◽  
Tracey L. Rogers ◽  
Geoff Dutton
Keyword(s):  
High Frequency ◽  
Seasonal Changes ◽  
Marine Mammals ◽  
Breeding Period ◽  
Testosterone Concentration ◽  
Acoustic Behaviour ◽  
Future Studies ◽  
Preliminary Information ◽  
Fur Seals ◽  
Hormonal Fluctuations

Seasonal changes in reproductive and acoustic behaviour are potentially affected by hormonal fluctuations; however, as it is difficult to routinely sample marine mammals, these associations are mostly inferred. Australian fur seals are vocal marine mammals that have a highly synchronous breeding season. The present study collected information on the testosterone concentration in faeces, vocalisations and behaviour of two captive male Australian fur seals to determine whether there are any associations between these variables. Positive associations were evident between the non-interactive agonistic behaviours (Head sway, Lay down and Head up) and an increase in calling rate of the bark calls in males. Barks were highest during August through to October, corresponding to the breeding period, while faecal testosterone levels peaked in September, coinciding with the high frequency in the calling rates of barks. Guttural threat calls were rarely heard throughout the year, but peaked in August. This call was not frequently heard but was associated with specific behaviours that were produced during more intense fighting interactions. This study presents preliminary information on the vocalisations, behaviour and hormone profiles for two captive Australian fur seals. Future studies with increased sample sizes from both wild and captive animals would clarify the intricate association between these factors.

scholarly journals Freshwater discharges drive high levels of methylmercury in Arctic marine biota

2015 ◽  
Vol 112 (38) ◽  
pp. 11789-11794 ◽  
Author(s):  
Amina T. Schartup ◽  
Prentiss H. Balcom ◽  
Anne L. Soerensen ◽  
Kathleen J. Gosnell ◽  
Ryan S. D. Calder ◽  
...  
Keyword(s):  
Water Column ◽  
Marine Mammals ◽  
River Mouth ◽  
Ecological Impacts ◽  
Trophic Levels ◽  
Indigenous Populations ◽  
Marine Biota ◽  
Terrestrial Organic Matter ◽  
Water Column Stratification ◽  
Freshwater Inputs

Elevated levels of neurotoxic methylmercury in Arctic food-webs pose health risks for indigenous populations that consume large quantities of marine mammals and fish. Estuaries provide critical hunting and fishing territory for these populations, and, until recently, benthic sediment was thought to be the main methylmercury source for coastal fish. New hydroelectric developments are being proposed in many northern ecosystems, and the ecological impacts of this industry relative to accelerating climate changes are poorly characterized. Here we evaluate the competing impacts of climate-driven changes in northern ecosystems and reservoir flooding on methylmercury production and bioaccumulation through a case study of a stratified sub-Arctic estuarine fjord in Labrador, Canada. Methylmercury bioaccumulation in zooplankton is higher than in midlatitude ecosystems. Direct measurements and modeling show that currently the largest methylmercury source is production in oxic surface seawater. Water-column methylation is highest in stratified surface waters near the river mouth because of the stimulating effects of terrestrial organic matter on methylating microbes. We attribute enhanced biomagnification in plankton to a thin layer of marine snow widely observed in stratified systems that concentrates microbial methylation and multiple trophic levels of zooplankton in a vertically restricted zone. Large freshwater inputs and the extensive Arctic Ocean continental shelf mean these processes are likely widespread and will be enhanced by future increases in water-column stratification, exacerbating high biological methylmercury concentrations. Soil flooding experiments indicate that near-term changes expected from reservoir creation will increase methylmercury inputs to the estuary by 25–200%, overwhelming climate-driven changes over the next decade.

scholarly journals Development of a Fish-Like Robot with a Continuous and High Frequency Snap-Through Buckling Mechanism Using a Triangular Cam

2021 ◽  
Vol 33 (2) ◽  
pp. 400-409
Author(s):  
Daisuke Nakanishi ◽  
Shoya Kobayashi ◽  
Kiichi Obara ◽  
Shotaro Matsumura ◽  
Yuichiro Sueoka ◽  
...  
Keyword(s):  
Thin Plate ◽  
Swimming Speed ◽  
High Frequency ◽  
Single Peak ◽  
Driving Mechanism ◽  
Drive Mechanism ◽  
Elastic Thin Plate ◽  
The Relationship

This study focuses on the high maneuverability of fish in water to design a fish-like robot via snap-through buckling. The aim of this study is to improve swimming speed by increasing the frequency at which snap-through buckling occurs. Here, we propose a novel drive mechanism using a triangular cam that can continuously generate snap-through buckling at a high frequency. In addition, we developed a fish-like robot via the proposed mechanism and analyzed the influence of the frequency of snap-through buckling on swimming speed. The results obtained indicate that swimming speed is improved and that the relationship between frequency and swimming speed exhibits a single peak. In other words, the swimming speed is reduced when the frequency is significantly increased. We also determined that swimming speed was improved using a wide elastic thin plate as the driving mechanism.

scholarly journals Drivers of nitrogen and phosphorus dynamics in a groundwater-fed urban catchment revealed by high frequency monitoring

2020 ◽  
Author(s):  
Liang Yu ◽  
Joachim C. Rozemeijer ◽  
Hans Peter Broers ◽  
Boris M. van Breukelen ◽  
Jack J. Middelburg ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Column ◽  
High Frequency ◽  
Water Bodies ◽  
Organic N ◽  
Hydrological Process ◽  
Nitrogen And Phosphorus ◽  
Urban Catchment ◽  
Event Scale ◽  
Frequency Monitoring

Abstract. Eutrophication of water bodies has been a problem causing severe degradation of water quality in cities. To gain mechanistic understanding of the temporal dynamics of nitrogen and phosphorus in a groundwater fed low-lying urban polder, we applied high frequency monitoring in Geuzenveld, a polder in the city of Amsterdam. The high frequency monitoring equipment was installed at the pumping station where water leaves the polder. From 2016 March to 2017 June, total phosphorus (TP), ammonium (NH4), turbidity, electrical conductivity (EC), and water temperature were measured at intervals smaller than 20 minutes. This paper discusses the results at three time scales: annual scale, rain event scale, and single pumping event scale. Mixing of upwelling groundwater and runoff was the dominant hydrological process and governed the temporal pattern of the EC, while N and P fluxes from the polder were also significantly regulated by primary production and iron transformations. The mixing of groundwater and runoff water governed water quality through variation of the intensity and duration of the events. For NH4, the dominant form of N in surface water originating from groundwater seepage, we observed low concentrations during the algae growing season, while concentrations were governed by mixing of groundwater and precipitation inputs in the late autumn and winter. The depletion of dissolved NH4 in spring suggests uptake by primary producers, consistent with high chlorophyll-a, O2, and suspended solids during this period. Total P and turbidity were high during winter, due to the release of reduced iron and P from anoxic sediment to the water column. Rapid Fe2+ oxidation in the water column is the major cause of turbidity. In the other seasons, P is retained in the sediment by iron oxides. Nitrogen is exported from the polder to the downstream water bodies throughout the whole year, mostly in the form of NH4, but as organic N in spring. P leaves the polder mainly during winter, primarily associated with Fe(OH)3 colloids and as dissolved P. Based on this new understanding of the dynamics of N and P in this low lying urban catchment, it is possible to formulate management strategies that can effectively control and reduce eutrophication situation in urban polders and receiving downstream waters.

Methylmercury biogeochemistry: a review with special reference to Arctic aquatic ecosystems

2014 ◽  
Vol 22 (3) ◽  
pp. 229-243 ◽  
Author(s):  
Igor Lehnherr
Keyword(s):  
Food Webs ◽  
Water Column ◽  
Human Health ◽  
Bottom Sediments ◽  
Aquatic Ecosystems ◽  
Marine Mammals ◽  
Primary Source ◽  
The Arctic ◽  
Arctic Biota

There has been increasing concern about mercury (Hg) levels in marine and freshwater organisms in the Arctic, due to the importance of traditional country foods such as fish and marine mammals to the diet of Northern Peoples. Due to its toxicity and ability to bioaccumulate and biomagnify in food webs, methylmercury (MeHg) is the form of Hg that is of greatest concern. The main sources of MeHg to Arctic aquatic ecosystems, the processes responsible for MeHg formation and degradation in the environment, MeHg bioaccumulation in Arctic biota and the human health implications for Northern Peoples are reviewed here. In Arctic marine ecosystems, Hg(II) methylation in the water column, rather than bottom sediments, is the primary source of MeHg, although a more quantitative understanding of the role of dimethylmercury (DMHg) as a MeHg source is needed. Because MeHg production in marine waters is limited by the availability of Hg(II), predicted increases in Hg(II) concentrations in oceans are likely to result in higher MeHg concentrations and increased exposure to Hg in humans and wildlife. In Arctic freshwaters, MeHg concentrations are a function of two antagonistic processes, net Hg(II) methylation in bottom sediments of ponds and lakes and MeHg photodemethylation in the water column. Hg(II) methylation is controlled by microbial activity and Hg(II) bioavailability, which in turn depend on interacting environmental factors (temperature, redox conditions, organic carbon, and sulfate) that induce nonlinear responses in MeHg production. Methylmercury bioaccumulation–biomagnification in Arctic aquatic food webs is a function of the MeHg reservoir in abiotic compartments, as well as ecological considerations such as food-chain length, growth rates, life-history characteristics, feeding behavior, and trophic interactions. Methylmercury concentrations in Arctic biota have increased significantly since the onset of the industrial age, and in some populations of fish, seabirds, and marine mammals toxicological thresholds are being exceeded. Due to the complex connection between Hg exposure and human health in Northern Peoples—arising from the dual role of country foods as both a potential Hg source and a nutritious, affordable food source with many physical and social health benefits—-reductions in anthropogenic Hg emissions are seen as the only viable long-term solution.

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