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More informations : science, papers, general ...

En français : cette page vous fournit certaines informations ou des articles, la plupart du temps scientifiques, en lien direct ou indirect avec le projet de recherche. Pour des informations plus détaillées, il vous est nécessaire d'avoir un compte pour bénéficier des avantages des partenaires en crowdfunding.

The purpose of this page is to provide readers some informations or articles, often linked to the research project, such as : science topics about sharks and the marine area under investigation,  hyperlinks to scientific and relevant papers, general informations about the work in progress (but, for more detailed informations, you should be a crowdfunder supporting SHARK RESEARCH Opal & Silver Coasts (EU), hence having a personal account for this web site - in other words, to benefit from the counterparts), and so on.

TO READ -> Global shark attack hotspots: Identifying underlying factors behind increased unprovoked shark bite incidence

Authors: Blake K.Chapman & DarylMcPhee

 

Received: October 22, 2015

Received in revised form: August 31, 2016

Accepted:September 15, 2016

Avilable online: September 24, 2016


DOI: http://dx.doi.org/10.1016/j.ocecoaman.2016.09.010

Ocean & Coastal Management 133 (2016) 72-84

Abstract

Unprovoked shark bite remains a rare, unlikely occurrence; however, shark bite incidence is increasingworld-wide. In an effort to understand why shark bite incidence is increasing, we examine recent trendsin unprovoked shark bite statistics and other media from the six global shark bite“hotspots”, the UnitedStates, South Africa, Australia, Brazil, Reunion Island and the Bahamas, and review recent literature thatidentifies potential causative factors that may contribute to rising shark bite incidence. Increases in sharkbite incidence are likely attributable to rises in human population, as well as other causative factors,including habitat destruction/modification, water quality, climate change and anomalous weather pat-terns and the distribution/abundance of prey. Our analysis shows that increases are likely the result of aset of conditions that disrupts the natural balance of an area at a local or regional level and increases theprobability of shark-human interaction. We also present recommendations for future management ofshark-human interaction.

URL: https://reader.elsevier.com/reader/sd/pii/S0964569116302058?token=C5F15256B6A1F07A2B13F5AD7A67868D123A1259A1A1D0A1C83410D3AC2EB379347F2D0C6912A012C7267F1E58363ED8

TO READ -> Sharks, rays and abortion: The prevalence of capture-induced parturition in elasmobranchs

Authors: Kye R. Adams, Lachlan C. Fetterplace, Andrew R. Davis, Matthew D. Taylor, Nathan A. Knott

 

Received: March 11, 2017

Revised: September 08, 2017

Accepted: October 09, 2017

Avilable online: October 28, 2017


DOI: https://doi.org/10.1016/j.biocon.2017.10.010

Biological Conservation, Vol. 217, January 2018, pp. 11-27

Abstract

The direct impacts of fishing on chondrichthyans (sharks, rays and chimeras) are well established. Here we review a largely unreported, often misinterpreted and poorly understood indirect impact of fishing on these animals — capture-induced parturition (either premature birth or abortion). Although direct mortality of discarded sharks and rays has been estimated, the prevalence of abortion/premature birth and subsequent generational mortality remains largely unstudied. We synthesize a diffuse body of literature to reveal that a conservative estimate of > 12% of live bearing elasmobranchs (n = 88 species) show capture-induced parturition. For those species with adequate data, we estimate capture-induced parturition events ranging from 2 to 85% of pregnant females (average 24%). To date, capture-induced parturition has only been observed in live-bearing species. We compile data on threat-levels, method of capture, reproductive mode and gestation extent of premature/aborted embryos. We also utilise social media to identify 41 social-media links depicting a capture-induced parturition event which provide supplementary visual evidence for the phenomenon. The mortality of embryos will have implications for elasmobranch populations, and there are limited options to deal with this problem. This review is the first to synthesize available data on capture-induced parturition in sharks and rays, and highlights an important ethical and management issue for fishers and managers deserving of much greater attention.

URL: http://www.sciencedirect.com/science/article/pii/S0006320717303634

TO READ -> The Effect of Background Music in Shark Documentaries on Viewers' Perceptions of Sharks

Authors : Andrew P. Nosal, Elizabeth A. Keenan, Philip A. Hsatings, Avelet Gneezy

 

Published: August 3, 2016
DOI: https://doi.org/10.1371/journal.pone.0159279

PLOS ONE, 2016, 11 (8) e015927

Abstract

Despite the ongoing need for shark conservation and management, prevailing negative sentiments marginalize these animals and legitimize permissive exploitation. These negative attitudes arise from an instinctive, yet exaggerated fear, which is validated and reinforced by disproportionate and sensationalistic news coverage of shark ‘attacks’ and by highlighting shark-on-human violence in popular movies and documentaries. In this study, we investigate another subtler, yet powerful factor that contributes to this fear: the ominous background music that often accompanies shark footage in documentaries. Using three experiments, we show that participants rated sharks more negatively and less positively after viewing a 60-second video clip of swimming sharks set to ominous background music, compared to participants who watched the same video clip set to uplifting background music, or silence. This finding was not an artifact of soundtrack alone because attitudes toward sharks did not differ among participants assigned to audio-only control treatments. This is the first study to demonstrate empirically that the connotative attributes of background music accompanying shark footage affect viewers’ attitudes toward sharks. Given that nature documentaries are often regarded as objective and authoritative sources of information, it is critical that documentary filmmakers and viewers are aware of how the soundtrack can affect the interpretation of the educational content.

URL: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0159279

TO READ -> Potential role of predators on carbon dynamics of marine ecosystems as assessed by a Bayesian belief network

Authors : Elisabeth K.A. Spiers a,1, Richard Stafford a,b,⁎,1, Mery Ramirez b, Douglas F. Vera Izurieta b,
Mariaherminia Cornejo b, Johnny Chavarria

Received: 5 April 2016
Received in revised form: 4 September 2016
Accepted: 14 October 2016
Available online: 17 October 2016

DOI: http://dx.doi.org/10.1016/j.ecoinf.2016.10.003

Ecological informatics, Volume ,36, November 2016, pp. 77-83

Abstract

While the effects of climate change on top predators are well documented, the role of predation on ecosystem level carbon production is poorly developed, despite it being a logical consequence of trophic dynamics. Trophic cascade effects have shown predator mediated changes in primary production, but we predict that predators should lower the overall biomass capacity of any system with top down control. Through a simple Bayesian belief network model of a typical marine foodweb, we show that predator removal, as is common through activities such as fishing and shark finning, results in higher biomasses of lower trophic level fish and zooplankton, resulting in higher net carbon production by the system. In situations common throughout much of the ocean, where activities such as shark finning and over fishing reduce the highest tropic levels, the probability of net carbon production increasing in the model was ~ 60%, and unlike previous studies on simple food chains, trophic cascade effects were not present. While the results are preliminary, and sources of uncertainty in data and models are acknowledged, such results provide even more strength to the argument to protect open sea fish stocks, and particularly large predators such as sharks, cetaceans and game fish.

URL: http://www.sciencedirect.com/science/article/pii/S1574954116301820

TO READ -> Patterns and ecosystem consequences of shark declines in the ocean

Authors : Francesco Ferretti, Boris Worm, Gregory L. Britten, Michael R. Heithaus, Heike K. Lotze

First published : 26 May 2010

DOI: 10.1111/j.1461-0248.2010.01489.x

Ecology Letters (2010) 13: 1055–1071

Abstract

Whereas many land predators disappeared before their ecological roles were studied, the decline of marine apex predators is still unfolding. Large sharks in particular have experienced rapid declines over the last decades. In this study, we review the documented changes in exploited elasmobranch communities in coastal, demersal, and pelagic habitats, and synthesize the effects of sharks on their prey and wider communities. We show that the high natural diversity and abundance of sharks is vulnerable to even light fishing pressure.

The decline of large predatory sharks reduces natural mortality in a range of prey, contributing to changes in abundance, distribution, and behaviour of small elasmobranchs, marine mammals, and sea turtles that have few other predators. Through direct predation and behavioural modifications, top-down effects of sharks have led to cascading changes in some coastal ecosystems. In demersal and pelagic communities, there is increasing evidence of mesopredator release, but cascading effects are more hypothetical. Here, fishing pressure on mesopredators may mask or even reverse some ecosystem effects. In conclusion, large sharks can exert strong top-down forces with the potential to shape marine communities over large spatial and temporal scales. Yet more empirical evidence is needed to test the generality of these effects throughout the ocean.

URL: http://onlinelibrary.wiley.com/doi/10.1111/j.1461-0248.2010.01489.x/abstract

TO READ -> 2000 years of frequent turbide activity in the Capbreton Canyon (Bay of Biscay)

Authors : S. Brocheray, M. Cremer, S. Zaragosi, S. Schmidt, F. Eynaud, L. Rossignol, H. Gillet

Received : 14 January 2013 ; Received in revised form: 4 November 2013 ; Accepted: 12 November 2013 ; Available online: 20 November 2013

DOI:

Marine Geology 347 (2014) 136-152

Abstract

Capbreton Canyon extends from 200 m water depth near the Aquitanian coast to 3000 m water depth before abruptly turning northward and merging with the Cap-Ferret systems. The Capbreton Canyon has been disconnected from the Adour River input since 1310 AD. Despite this situation, modern sedimentary activity is evident in the first kilometres from the head. Present sedimentation in the Capbreton Canyon was studied by combined analysis of acoustic data and cores. Cores from the topographic highs document moderate hemipelagic sedimentation and record the global climatic signal of the Bay of Biscay.Within the canyon, at±80 km from the head, on terraces bordering the thalweg at 1600 mwater depth, cores attest to recent turbidite activity. Massive medium sand is restricted to the thalweg floor, where sediment transfer dominates. Fine-grained turbidites are preferentially accumulated on the shallower terraces near the thalweg (the accumulation rate is 3 and 1 cm/year at 75 m and 125 m above the thalweg, respectively). On a higher terrace (225 m), turbidite sequences are absent or too thin to be preserved from bioturbation. The sedimentation rate is lower (approximately 0.17 cm/year) but still 10 times higher than the hemipelagic sedimentation outside the Capbreton Canyon. We demonstrate that frequent turbidity currents (1/year) are currently responsible for very high accumulation of dominantly fine-grained sediments on the terraces that are the nearest from the thalweg. We assume an impact of nepheloid layers on the sedimentation of the highest terraces. Looking for any impact on sediment supply of the disconnection of the Capbreton Canyon head from the Adour Rivermouth, it appears that the impact on the sedimentation affected the nature of the particles, which are less carbonate-rich, rather than the quantity of sediments. This result suggests that the longshore drift at the canyon head and hydrodynamic events are major factors in the sedimentation
of Capbreton Canyon.

URL: http://www.sciencedirect.com/science/article/pii/S0025322713002491

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