Bite marks on early Holocene Tursiops truncatus fossils from the North Sea indicate scavenging by rays (Chondrichthyes, Rajidae)

2009 ◽  
Vol 88 (3) ◽  
pp. 169-175
Author(s):  
H.H. van Netten ◽  
J.W.F. Reumer
Keyword(s):  
Natural History ◽  
North Sea ◽  
Tursiops Truncatus ◽  
Marine Mammals ◽  
Real Life ◽  
Early Holocene ◽  
History Museum ◽  
Bite Marks ◽  
The North ◽  
The North Sea

AbstractA number of Tursiops truncatus mandibles in the collection of fossil marine mammals in the Rotterdam Natural History Museum have marks consisting of several parallel linear grooves. These marks are also found on four atlas complexes, a scapula and on one vertebra. The hypothesis that they are bite marks and were caused by scavenging rays (Rajidae, Chondrichthyes) was tested with a real-life experiment using different shark and ray species, allowing them to scavenge on cow ribs as proxies for the dolphin bones. The bite marks of these animals were compared with the fossil marks and show that the fossil marks are most likely caused by scavenging rays.

scholarly journals On the Occurrence of Squilla desmaresti in the North Sea

1902 ◽  
Vol 6 (3) ◽  
pp. 387-388 ◽  
Author(s):  
F. Jeffrey Bell
Keyword(s):  
Natural History ◽  
North Sea ◽  
Natural History Museum ◽  
History Museum ◽  
Dogger Bank ◽  
The North ◽  
The North Sea

So far as I have been able to discover, there is no record of the presence of this or any other Squilla in the North Sea; to make sure I inquired of Dr. Hoek, whose experience is unrivalled, and he assures me that the only record is that of an Erichtheus stage, discovered on the Dogger Bank during the cruise of the Pommerania (1872). Early in May (1901) I received through the Director of the Natural History Museum a specimen of Squilla, as to the rarity of which in the Channel he called my attention.

Status of marine mammals in the North sea

1990 ◽  
Vol 26 (2-4) ◽  
pp. 427-435 ◽  
Author(s):  
P.J.H. Reijnders ◽  
K. Lankester
Keyword(s):  
North Sea ◽  
Marine Mammals ◽  
The North ◽  
The North Sea

Sources and Fate of PCBs in the North Sea: A Review of Available Data

1991 ◽  
Vol 24 (10) ◽  
pp. 77-85 ◽  
Author(s):  
J. Klamer ◽  
R. W. P. M. Laane ◽  
J. M. Marquenie
Keyword(s):  
Adverse Effects ◽  
North Sea ◽  
German Bight ◽  
Marine Mammals ◽  
Wadden Sea ◽  
Annual Basis ◽  
The North ◽  
Total Input ◽  
Seal Population ◽  
The North Sea

From literature data it is calculated that on an annual basis, 11 to 17 tonnes of PCBs enter the North Sea. Largest sources are the Atlantic Ocean and the atmosphere: together they account for 60-79% of the total input. Sources with greatest impact are the rivers, sewers and sludge. Highest concentrations are found close to the Dutch shore and in the German Bight. The PCB levels result in adverse effects on the seal population in the Wadden Sea. Of the total world PCB production, at least 57% is still in use and their future dispersal into the oceans cannot easily be controlled. If the increase in ocean PCB concentration continues, it may ultimately result in the extinction of fish-eating marine mammals.

scholarly journals Ecosystem-based management objectives for the North Sea: riding the forage fish rollercoaster

2013 ◽  
Vol 71 (1) ◽  
pp. 128-142 ◽  
Author(s):  
M. Dickey-Collas ◽  
G. H. Engelhard ◽  
A. Rindorf ◽  
K. Raab ◽  
S. Smout ◽  
...  
Keyword(s):  
North Sea ◽  
Marine Mammals ◽  
Management Strategies ◽  
Ecosystem Approach ◽  
Integral Approach ◽  
Forage Fish ◽  
Ecosystem Based Management ◽  
The North ◽  
Management Objectives ◽  
The North Sea

Abstract Dickey-Collas, M., Engelhard, G. H., Rindorf, A., Raab, K., Smout, S., Aarts, G., van Deurs, M., Brunel, T., Hoff, A., Lauerburg R. A. M., Garthe, S., Haste Andersen, K., Scott, F., van Kooten, T., Beare, D., and Peck, M. A. Ecosystem-based management objectives for the North Sea: riding the forage fish rollercoaster. – ICES Journal of Marine Science, 71: . The North Sea provides a useful model for considering forage fish (FF) within ecosystem-based management as it has a complex assemblage of FF species. This paper is designed to encourage further debate and dialogue between stakeholders about management objectives. Changing the management of fisheries on FF will have economic consequences for all fleets in the North Sea. The predators that are vulnerable to the depletion of FF are Sandwich terns, great skua and common guillemots, and to a lesser extent, marine mammals. Comparative evaluations of management strategies are required to consider whether maintaining the reserves of prey biomass or a more integral approach of monitoring mortality rates across the trophic system is more robust under the ecosystem approach. In terms of trophic energy transfer, stability, and resilience of the ecosystem, FF should be considered as both a sized-based pool of biomass and as species components of the system by managers and modellers. Policy developers should not consider the knowledge base robust enough to embark on major projects of ecosystem engineering. Management plans appear able to maintain sustainable exploitation in the short term. Changes in the productivity of FF populations are inevitable so management should remain responsive and adaptive.

Sign in / Sign up

Export Citation Format

Share Document