Bruinvissen hebben grote en vette vissen nodig : Promotieonderzoek Mardik Leopold (Wageningen University)
Leopold, Mardik - \ 2015
phocoenidae - phocoena - causes of death - starvation - north sea - fish feeding - cetacea
Blue whale sightings in Antarctica west of the Greenwich meridian, Januart 2015
Geelhoed, S.C.V. ; Feij, B. ; Franeker, J.A. van; Herr, H. ; Janinhoff, N. ; McKay, S.J. ; Muller, S. ; Thomisch, K. ; Verdaat, J.P. ; Viquerat, S. - \ 2015
[s.l.] : International Whaling Commission - 9
whales - surveying - observation - cetacea - antarctica - walvissen - karteren - observatie - cetacea - antarctica
During the RV Polarstern PS 89 (ANT-XXX/2) expedition from Cape Town to Atka Bay and back, 20 sightings of 26 individual blue whales (Balaenoptera musculus) were recorded in Antarctic waters west of the Greenwich Meridian between 16-20 January 2015. These observations suggest a more westerly extension of a reported hot spot between the Greenwich Meridian and 20°E.
User guide: Handheld hydrophone for recording cetaceans at sea (version 1.0)
Verdaat, J.P. ; Lucke, K. - \ 2014
Den Helder : IMARES (Report / IMARES ) - 18
handleidingen - geluidsopnames - cetacea - marien milieu - opnameapparatuur - guide books - recordings - cetacea - marine environment - recording instruments
Marine mammals spend most of their time underwater which sometimes makes it difficult to detect them from the surface. At the same time, most cetaceans (toothed and baleen whales) produce a variety of sounds underwater and since sound travels easily in water, these sounds can normally be picked up even at distances beyond those of visual detection. Several studies have shown that the analysis of underwater sound recordings can complement the existing research efforts to assess the presence and distribution of cetacean species in the Caribbean waters and elsewhere. We hope the system will be easy to use even by untrained personnel and robust enough to withstand the strain of being used in the marine environment. This user’s guide is intended to serve as a practical illustrated step by step users guide useful information in addition to the manual provided with every recording system.
Noise logger overview
Lucke, K. - \ 2014
IJmuiden : IMARES (Report / IMARES ) - 44
marien milieu - caribische zee - geluidsopnames - opnameapparatuur - zeezoogdieren - cetacea - marine environment - caribbean sea - recordings - recording instruments - marine mammals - cetacea
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.
Elusive marine mammals explored : charting under-recorded areas to 160699 and distribution of cetaceans using multi-method approaches and platforms of opportunity
Boer, M.N. de - \ 2013
Wageningen University. Promotor(en): Peter Reijnders, co-promotor(en): Marten Scheffer. - Wageningen : Wageningen UR - ISBN 9789461737168 - 282
cetacea - zeezoogdieren - zeedieren - geografische verdeling - methodologie - dierecologie - aquatische ecologie - gegevens verzamelen - zoögeografie - cetacea - marine mammals - marine animals - geographical distribution - methodology - animal ecology - aquatic ecology - data collection - zoogeography
Survey for small cetaceans over the Dogger Bank and adjacent areas in summer 2011
Gilles, A. ; Peschko, V. ; Scheidat, M. ; Siebert, U. - \ 2012
Galway : ASCOBANS
mariene gebieden - noordzee - cetacea - populatiedynamica - marine areas - north sea - cetacea - population dynamics
Review of New Information on Population Size, Distribution, Structure and Causes of Any Changes. The distribution of small cetaceans in the offshore areas of the North Sea has been in the interest of researchers for many years. Information on abundance and distribution is essential to assess the impact of bycatch and other anthropogenic threats, and as basis for management plans to ensure the favourable conservation status of these species. In 2011 we conducted a dedicated aerial line transect survey of the Dogger Bank and adjacent areas (UK, NL, DK, GE waters) in order to investigate the importance of this marine feature as summer habitat for marine mammals.
Shortlist Masterplan Wind Ship-based monitoring of seabirds and cetaceans
Bemmelen, R.S.A. van; Geelhoed, S.C.V. ; Leopold, M.F. - \ 2011
Den Helder : IMARES (Report / IMARES Wageningen UR C099/11) - 90
zeevogels - zeezoogdieren - cetacea - monitoring - offshore - noordzee - sea birds - marine mammals - cetacea - monitoring - offshore - north sea
During April 2010 – February 2011, monthly surveys of seabirds and marine mammals were conducted aboard ships engaged in plankton surveys. After many years of little or no effort in far offshore areas of the DCS, this series of surveys provided the first recent ship-based data on seabirds, covering a large area (the entire Dutch Continental Shelf (DCS), including some Belgian and British waters) almost yearround. Due to changes in the design of the survey grid, the use of several ships, spells of bad weather conditions and seasonal differences in the number of daylight hours, the resulting coverage is not evenly spread in space and time. Still, both in terms of areas covered and detailed data gathered, this series of surveys complement the aerial surveys carried out under the same programme Shortlist Masterplan Wind. By surveying beyond the designated areas for round II offshore wind farms on the DCS, areas that might be targeted for round III, such as the shallow Dogger Bank area, got a first boost in T-zero survey effort. From April 2010 till February 2011 11 surveys, totalling to 48 at-sea days, 4610 5-minute counts were conducted over a distance of 9021 km. At a counting strip width of mostly 300 m (200 m over a very small percentage of the counts), this amounts to a total surveyed area of 2706 km2. The surveys have provided rough data on seabird distribution in far offshore areas. In total, 54,593 individuals of 90 bird species were recorded, from which 15,003 individuals of 36 species were recorded within the counting strip. Marine mammals were represented by 616 individuals of seven species, of which 389 individuals of six species were seen within the counting strip. Flying heights were noted for 5044 clusters of individuals, covering 75 species. Behaviour was noted for 1790 (clusters of) individuals. Apart from birds and marine mammals, 352 balloons were counted (of which 164 were within the counting strip) and proved omnipresent in periods of offshore winds. These surveys have identified several issues that should be taken into account in future planning of wind farms. Divers, which are the highest ranked species in terms of sensitivity to wind farms, can be encountered migrating anywhere in offshore waters and sightings of White-billed Divers at the Dogger Bank suggest the existence of a small wintering population of this near-threatened species. In relation to this, potential effects of wind farms on offshore species, such as Northern Fulmars, Atlantic Puffins, Little Auks and cetaceans, are unknown as current wind farms are located near shore where these species do not occur in large numbers.
Stomach Content of a Juvenile Bolivian River Dolphin (Inia geoffrensis boliviensis) from the Upper Madeira Basin, Bolivia
Aliaga-Rossel, E. ; Beerman, A.S. ; Sarmiento, J. - \ 2010
Aquatic Mammals 36 (2010)3. - ISSN 0167-5427 - p. 284 - 287.
cetacea - iniidae
The article presents a study about the stomach content of a juvenile Bolivian river dolphin (Inia geoffrensis boliviensis), an endemic subspecies of the Amazon River dolphin, found in the upper Madeira River basin in Bolivia. The study finds that the stomach of Bolivian river dolphin contained a mixture of partially digested fish remains and a nematode. It says that the diet of adult Bolivian river dolphins include crabs and unidentified fish species, including members of the Characidae family.
Annual Report of the Netherlands to the European Commission on the implementation of Council regulation 812/2004 on cetacean bycatch
Couperus, A.S. - \ 2010
IJmuiden : IMARES (CVO report / Centre for Fishery Research (CVO) 10.006) - 15
visserij - cetacea - monitoring - pelagische visserij - bijvangst - fisheries - cetacea - monitoring - pelagic fishery - bycatch
This report contains the results of the ongoing monitoring programme on the incidental bycatch of cetaceans in Dutch pelagic fisheries in 2009.
Annual Report of the Netherlands to the European Commission on the implementation of Council Regulation 812/2004 on cetacean bycatch
Couperus, A.S. - \ 2009
IJmuiden : IMARES (CVO report / Centre for Fishery Research (CVO) 09.006) - 24
visserij - cetacea - dolfijnen - vangstsamenstelling - netten - bemonsteren - inventarisaties - pelagische visserij - vismethoden - bijvangst - fisheries - cetacea - dolphins - catch composition - nets - sampling - inventories - pelagic fishery - fishing methods - bycatch
This report contains the results of the ongoing monitoring programme on the incidental bycatch of cetaceans in Dutch pelagic fisheries in 2008. Further, this report presents the results of a pilot observer study in set net fisheries. In the Netherlands about 90 vessel are known to land fish caught by set nets. The main target species is sole, which is fished with tangle nets.
Cetaceans stranded in the Netherlands from 1998 to 2007
Camphuysen, C.J. ; Smeenk, C. ; Addink, M. ; Grouw, H. van; Jansen, O.E. - \ 2008
Lutra 51 (2008)2. - ISSN 0024-7634 - p. 87 - 122.
cetacea - megaptera novaeangliae - dolfijnen - phocoena - balaenopteridae - megaptera - physeter - tursiops truncatus - lagenorhynchus - kustwateren - strandgronden - noordzee - cetacea - megaptera novaeangliae - dolphins - phocoena - balaenopteridae - megaptera - physeter - tursiops truncatus - lagenorhynchus - coastal water - beach soils - north sea
Between 1998 and 2007, 2063 cetaceans were found stranded in the Netherlands, representing at least 14 species. Two species, humpback whale (Megaptera novaeangliae) and Blainville's beaked whale (Mesoplodon densirostris), are additions to the Dutch list. Apart from the first humpback whales, relatively many balaenopterid whales were found in comparison with previous decades. Range extension of recovering populations may explain part of this trend. However, the decline in strandings frequency in sperm whales (Physeter macrocephalus), another species with a slowly recovering Atlantic population but with a distinct peak in strandings in the 1990s, suggests that the factors underlying these changes are complex. During the 20th century, the strandings frequency of some dolphin species regularly occurring in the North Sea has changed markedly. Bottlenose dolphins (Tursiops truncatus) disappeared in the 1960s, common dolphins (Delphinus delphis) were fairly numerous during some decades in the mid-20th century, and white-beaked dolphins (Lagenorhynchus albirostris) became abundant and virtually replaced bottlenose dolphins in the strandings records since the 1970s. Numbers of stranded harbour porpoises (Phocoena phocoena) continued to increase over the years. All individual cases other than harbour porpoises are listed in this paper, reporting species, (late, locality, reporter, sex, total length (TL), collected remains, and remarks. A total of 1968 reports of stranded harbour porpoises were received, ranging from 59 in 1998 to 539 in 2006. It is estimated that along the North Sea coast at least 19% more porpoises were washed ashore than were actually recorded. On the Wadden Sea islands, this discrepancy is estimated as at least 30%. The mean length of porpoises declined gradually with time and the sex ratio was male-biased in all subregions. From measurements (TL) it is concluded that circa 72% were juveniles, with small proportions of adults (15.5%; unsexed and male male animals of TL > 150cm, female female animals of TL > 145 cm) and neonates or stillborns (12.4%; all porpoises of TL <90 can). The predominance of males is evident only in juveniles (62.8%), whereas the sex ratio in adults and neonates is not significantly skewed. 20.2% of the females and 12.1% of the males are large enough to tie regarded as sexually mature. The overall strandings pattern of the harbour porpoise is bimodal, with peaks in strandings in March-April and August. Presumed adults were proportionally numerous in winter (December-January) and in June, whereas about a quarter of all porpoises found in July, August and September were neonates or stillborn. At least ten porpoises were very large (TL estimated or measured > 170 cm) and a minimum of 14 females were either pregnant or had recently given birth. It should be noted, however, that only a small proportion of the porpoises was checked for reproductive status. Foetuses ranged in length Prom 22 cm (December 2006) to 75 cm (May 2004). Many porpoises were decomposed when found and these were buried or removed and destroyed. At least 38 cases were reported with evident external signs of by-catches, another 17 carcasses had been heavily mutilated with knives. A combination of histopathology and gross pathology of 255 harbour porpoises found in the period 1990-2000 and in 2006 and 2007 suggested that between 50 and 60% of the animals showed signs of definite or probable by-catch in fishing gear.Many of the stranded porpoises found had come into conflict with fisheries and had (lied, as several of the lrger (baleen) whales did. A dialogue with fisheries organisations is proposed to explore the issue further and to try and mitigate the problem.
The influenze of signal parameters on the sound source localization ability of a harbor popoise (Phocoena phocoena)
Kastelein, R.A. ; Haan, D. de; Verboom, W.C. - \ 2007
Journal of the Acoustical Society of America 122 (2007)2. - ISSN 0001-4966 - p. 1238 - 1248.
bottle-nosed-dolphin - acoustic alarms - tursiops-truncatus - toothed whales - floating pen - lower bay - cetacea - mortality - gillnets - behavior
It is unclear how well harbor porpoises can locate sound sources, and thus can locate acoustic alarms on gillnets. Therefore the ability of a porpoise to determine the location of a sound source was determined. The animal was trained to indicate the active one of 16 transducers in a 16-m-diam circle around a central listening station. The duration and received level of the narrowband frequency-modulated signals (center frequencies 16, 64 and 100 kHz) were varied. The animal's localization performance increased when the signal duration increased from 600 to 1000 ms. The lower the received sound pressure level (SPL) of the signal, the harder the animal found it to localize the sound source. When pulse duration was long enough (1 s) and the received SPLs of the sounds were high (34¿50 dB above basic hearing thresholds or 3¿15 dB above the theoretical masked detection threshold in the ambient noise condition of the present study), the animal could locate sounds of the three frequencies almost equally well. The porpoise was able to locate sound sources up to 124° to its left or right more easily than sounds from behind it.
Monitoring of incidental catches of cetaceans by Dutch pelagic trawlers in 2006
Couperus, A.S. - \ 2007
IJmuiden : Centrum voor Visserijonderzoek (CVO report 07.004) - 17
cetacea - visserij - monitoring - nederland - visvangsten - cetacea - fisheries - monitoring - netherlands - fish catches
Incidental catches of pelagic megafauna by the Dutch pelagic fleet in the Mauritanian Exclusive Economic Zone during the years 1999 - 2003
Hofstede, R. ter; Zeeberg, J.J. ; Haan, D. de; Couperus, A.S. ; Mantingh, I.T. - \ 2004
IJmuiden : RIVO (RIVO report C032/04) - 20
pelagische visserij - visserij - vangstsamenstelling - bijvangst - cetacea - haaien - raja - xiphias gladius - maanvissen - cheloniidae - mauritanië - pelagic fishery - fisheries - catch composition - bycatch - cetacea - sharks - raja - xiphias gladius - sunfishes - cheloniidae - mauritania
This report presents all registered catches of pelagic megafauna by the Dutch pelagic fleet in the Mauritanian Exclusive Economic Zone during the years 1999-2003. ‘By-catches’ incidentally include large species, notably cetaceans, sea turtles, sharks, rays, and some large pelagic fish such as swordfish and ocean sunfish. All observations were made in the framework of different projects of the Netherlands Institute for Fisheries Research (RIVO B.V.) in the area, financed by the Dutch Ministry of Agriculture, Nature Management, and Fisheries (LNV) and partly by the Redersvereniging voor Zeevisserij, part of the Pelagic Freezer-Trawler Association (PFA): “Assessment of Sardinella and other small pelagics in West Africa” (313-1230001), “Application of remote sensing data to analyse the distribution and recruitment of sardinella” (313-1230002), and “Preventing by-catches of protected or endangered species in the pelagic trawl fishery in West Africa” (313-1230003). The sampling procedures of incidentally caught pelagic megafauna on board of Dutch pelagic freezer-trawlers in Mauritania throughout the period 1999-2003 are evaluated in this report. The collected raw data on this by-catch of large species is whenever possible validated with an observation factor, shortcomings are discussed, and recommendations for improvements are given. This report presents raw data and explicitly avoids extrapolations up to mission or even fleet level.