986 research outputs found
A Proposal Towards a Dutch Caribbean Marine Mammal Sanctuary
Based on the goals set forth in the Dutch Biodiversity Policy Programme, The Netherlands has a traditionally strong commitment to protect biodiversity and marine mammals both internationally and in its own national and Kingdom waters. Last year the responsible ministry, namely the Netherlands Ministry of Economic Affairs, Agriculture and Innovation (EL&I), developed a management plan for the biological resources of the recently declared Dutch Caribbean Exclusive Economic Zone. The Dutch Caribbean EEZ was formally declared on June 10, 2010, and amounts to more than 90.000 km2 of diverse tropical marine habitats. One of the key ambition coming forth from that plan was to develop a Dutch Caribbean Marine Mammal Sanctuary (MMS). This report provides the necessary review and background on which to base such an endeavour. Our updated review establishes beyond doubt that the Dutch Caribbean EEZ has a rich and diverse marine mammal fauna which merits more extensive protection. Even though the fauna is only poorly known, based almost exclusively on incidental sightings and strandings, it amounts to a minimum of 19 marine mammal species, and possibly up to more than 30. Without exception, all documented species appear on protected species lists of one or more treaties ratified by the Kingdom, and/or its constituent countries. Large differences are apparent between the leeward and windward sectors of the Dutch Caribbean EEZ, both in terms of species composition and conservation issues. Throughout the region, cetaceans are playing an increasingly important role in island economies as an important natural attraction for eco-based recreation and tourism, and in this respect the Dutch Caribbean also possesses major potential. We here propose the establishment of a MMS as the cornerstone to sustainable conservation and management of these charismatic animals. Ecological arguments for the establishment of habitat protection by means of the concept of sanctuaries are outlined, as are the many environmental issues that would eventually need to be addressed within the sanctuary. Legal designation of a marine mammal sanctuary (MMS) would form the first and most important step which provides the framework for all broader (international cooperation) and in depth (knowledge and conservation development) initiatives. Once established, the fuller implementation of a marine mammal sanctuary should be seen as a gradual process, involving development of knowledge, policy, rules and regulations, public and stakeholder participation. In this the Netherlands would follow and importantly reinforce the efforts of other nations who have already established MMS’s within the region. Favourable pre-conditions for the establishment of a MMS in the Dutch Caribbean include the fact that a) all cetaceans are already have a legal status in the Dutch Caribbean EEZ which calls for actual protection, b) the most deleterious fishing practices are already significantly limited and controlled within Kingdom waters, c) the key enforcer, namely the Coastguard, is already strongly present (largely due to other reasons), d) the islands generally have a strong tradition of marine protected areas in coastal habitat, e) the incremental costs for research and enforcement needed to establish a sanctuary is modest, f) public support is high, thanks to the generally high level of development and awareness of the public, g) indigenous fishery practices do not conflict with cetacean conservation, and h) whale watching interests are only in their infancy. We conclude our review by proposing the following key action points to establishing a MMS: a) Legal designation of the EEZ (one or both sectors) as MMS, along with establishment of legal guidelines for interacting with cetaceans (whale watching). b) Establish bonds of cooperation with sister sanctuaries in the region (France, USA, Dominican Republic), (e.g. regional stranding and sightings data network). c) Conduct baseline quantitative surveys of cetacean distribution and assessments in light of sources of deleterious sound sources and risks of vessel strikes. d) Review and adapt existing national and insular legal frameworks to improve these, preferably by developing separate and standardized marine mammals legislation. e) Develop information systems to promote the development of a whale (cetacean) watching industry. f) Train and equip marine parks and island veterinarians to conduct elementary autopsies and collect basic stranding specimens for analysis of causes of mortality, contamination levels and genetics, and link them to international academic institutions who will accept and analyse the specimens in regional context. g) Develop species action plans (e.g. humpback). h) Conduct cetacean surveys and management reviews every 5 years to assess marine mammal status and conservation progress
Noise logger overview
In our attempt to monitor the presence of marine mammals, especially cetaceans, their acoustic activity opens the opportunity for us to eavesdrop and to study their behaviour passively through listening and detecting their sounds and vocalisations. This overview of underwater sound recording systems which can be used to study the life of the mainly cryptic marine mammal species is intended to facilitate researchers, potential funding bodies and finally regulators with information on the potential of this technique, its limitations and most importantly with technical details and a market overview
Pilotproject voor het gebruik van onderwater-geluidloggers voor het monitoren van omgevingsfactoren
Om onderwatergeluid op te kunnen nemen, zijn in de winter van 2011/2012 voor een periode van meer dan drie maanden twee geluidsloggers geplaatst in de Eems. De locaties zijn zo gekozen dat één van de recorders vlakbij de ingang van de Eemshaven hangt, terwijl de andere vlakbij de zandbank Hond & Paap gesitueerd is. Het doel van dit pilotproject is het testen van de bruikbaarheid van de techniek om geluidsuitstoot, van zowel bouwgerelateerde activiteiten bij de Eemshaven als niet aan de bouw gerelateerde activiteiten, te identificeren en deze te koppelen aan de gerapporteerde tijdsinformatie van de bouwactiviteiten. De opnames lieten zien dat het niveau van het achtergrondgeluid in de Eems vooral vanwege de sterke stroming relatief hoog is. Passerende Scheepvaart op de Eems bleek de grootste bijdrage te leveren aan het totale onderwatergeluid ter plaatse van de geluidsloggers, waarbij dit geluid verschillende keren bouwgerelateerde activiteiten maskeerde. Het resultaat laat zien dat verschillende typen geluidsbronnen, naast de scheepvaart op de Eems, met zekerheid konden worden geïdentificeerd
New Constraints on the Energetics, Progenitor Mass, and Age of the Supernova Remnant G292.0+1.8 Containing PSR J1124-5916
We present spatially resolved spectroscopy of the supernova remnant (SNR)
G292.0+1.8 with the Chandra X-ray observatory. This SNR contains the 135 ms
pulsar, J1124-5916. We apply non-equilibrium ionization (NEI) models to the
data. By comparing the derived abundances with those predicted from
nucleosynthesis models, we estimate a progenitor mass of 30-40 solar masses. We
also derive the intrinsic parameters of the supernova explosion such as its
energy, the age of the SNR, the blast wave velocity, and the swept-up mass. In
the Sedov interpretation, our estimated SNR age of 2,600 years is close to the
pulsar's characteristic age of 2,900 years. This confirms the pulsar/SNR
association and relaxes the need for the pulsar to have a non-canonical value
for the braking index, a large period at birth or a large transverse velocity.
We discuss the properties of the pulsar wind nebula (PWN) in the light of the
Kennel and Coroniti model and estimate the pulsar wind magnetization parameter.
We also report the first evidence for steepening of the power law spectral
index with increasing radius from the pulsar.Comment: 5 pages, 3 figures. To appear in ApJL, Feb 1 2003 (submitted Oct 9
2002, accepted Dec 19 2002
X-ray Observation and Analysis of The Composite Supernova Remnant G327.1-1.1
Based on the data from the observation of the SNR G327.1-1.1 by ASCA and
ROSAT, we find that G327.1-1.1 is a composite remnant with both a nonthermal
emission component and a diffuse thermal emission component. The nonthermal
component is well fitted by a power-law model with photon index about 2.2. This
component is attributed to the emission from the synchrotron nebula powered by
an undiscovered central pulsar. The thermal component has a temperature of
about 0.4 keV. We attribute it to the emission from the shock-heat swept-up
ISM. Its age, explosion energy and density of ambient medium are derived from
the observed thermal component. Some charactistics about the synchrotron nebula
are also derived. We search for the pulsed signal, but has not found it. The
soft X-ray(0.4 - 2 keV) and hard X-ray(2 - 10 keV) images are different, but
they both elongate in the SE-NW direction. And this X-ray SE-NW elongation is
in positional coincidence with the radio ridge in MOST 843MHz radio map. We
present a possibility that the X-ray nonthermal emission mainly come from the
trail produced by a quickly moving undiscoverd pulsar, and the long radio ridge
is formed when the pulsar is moving out of the boundary of the plerionic
structure.Comment: 20 pages, 4 Postscript figures, aasms4.sty and psfig.sty, to be
published in Astrophysical Journal, January 20, 1999, Vol. 51
Telemetry studies in harbour porpoises - An overview of the technical and practical state of the art
Information on the life functions and ecology of harbour porpoises is still scarce. Only a limited number of animals are available for research in controlled situations. Satellite tracking allows to gather information on individual movements of harbour porpoises, hence providing direct insight into the individual lifestyle of a free-ranging animal. Moreover, satellite telemetry is a powerful method for directly identifying the cause-effect relationship between anthropogenic activities and the animal’s behaviour. Harbour porpoises have been tagged with satellite transmitters already for almost two decades. This document is intends to provide a comprehensive overview of the relevant aspects of telemetry studies in harbour porpoises in Dutch waters and also give an overview of the latest technical developments in this field. Based on this information the strategy for further development and use of telemetry in harbour porpoises can be shaped
Neurologic phenotype of Schimke immuno-osseous dysplasia and neurodevelopmental expression of SMARCAL1
Schimke immuno-osseous dysplasia (OMIM 242900) is an uncommon autosomal-recessive multisystem disease caused by mutations in SMARCAL1 (swi/snf-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a-like 1), a gene encoding a putative chromatin remodeling protein. Neurologic manifestations identified to date relate to enhanced atherosclerosis and cerebrovascular disease. Based on a clinical survey, we determined that half of Schimke immuno-osseous dysplasia patients have a small head circumference, and 15% have social, language, motor, or cognitive abnormalities. Postmortem examination of 2 Schimke immuno-osseous dysplasia patients showed low brain weights and subtle brain histologic abnormalities suggestive of perturbed neuron-glial migration such as heterotopia, irregular cortical thickness, incomplete gyral formation, and poor definition of cortical layers. We found that SMARCAL1 is highly expressed in the developing and adult mouse and human brain, including neural precursors and neuronal lineage cells. These observations suggest that SMARCAL1 deficiency may influence brain development and function in addition to its previously recognized effect on cerebral circulation
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