Conjoined harbour porpoise twins found


Conjoined North Sea harbour porpoise twins

From Deinsea, Online Journal of the Natural History Museum Rotterdam in the Netherlands:

The first case of conjoined twin harbour porpoises Phocoena phocoena (Mammalia, Cetacea)

7 June 2017

ABSTRACT

The harbour porpoise (Phocoena phocoena) is the smallest and most abundant cetacean in NW European continental shelf waters. Their global abundance numbers at least ~700,000 individuals. Within the North Sea, total abundance has recently been estimated at approximately 345,000 animals. The species reproduces at a rate of one offspring every 1-2 years. In this article we describe a case of conjoined twins in the harbour porpoise: a parapagus dicephalus bycaught in the Southern North Sea in May 2017. Reports of conjoined twins in wild mammals are extremely scarce.

This case concerns the second known case of twinning and the first case of conjoined twins in P. phocoena, the fourth known case of parapagus dicephalus in any cetacean species and the tenth known case of conjoined twinning in a cetacean species.

Marine biology at gas platform


In this Dutch 14 February 2016 video, marine biologist Joop Coolen investigates marine life at a gas platform in the North Sea with an airlift sampler.

Coolen’s research indicates that concrete structures in the sandy North Sea bottom environment increase biodiversity. So, it would be better not to remove platforms after work at them stops.

North Sea coast birds video


This is a 19 January 2017 North Sea coast birds video from the Netherlands.

Including sanderling, purple sandpiper, red-breasted merganser, red-throated diver, razorbill and others.

Cuckoo wrasse, new fish species for the Netherlands


This is a male cuckoo wrasse video, made in an aquarium.

Translated from the Dutch Stichting Anemoon ichthyologists:

21 December 2016 – On the Cleaver Bank, 150 kilometers northwest of Texel island, using an ROV, an underwater vehicle operated remotely, a cuckoo wrasse has been observed. This is the first report of this species in Dutch waters.

What people ate when North Sea was land


Doggerland people, reconstruction

Translated from Historiek.net in the Netherlands:

Archaeologists discover menu of the hunter-gatherers of ‘Doggerland

Editors – November 1, 2016, 15:51

Some 8000 years ago mainly freshwater fish was on the menu of the hunter-gatherers of Doggerland “the drowned landscape between the Netherlands, England and Denmark. This conclude Dutch archaeologists based on isotopic analysis of prehistoric human skeletal remains from the North Sea.

The discovery gives clues about the occupation of this vast landscape drowned in the middle Stone Age (Mesolithic) and the effects of climate change on earlier societies.

Preferring fish

The isotopic study was conducted by the University of Groningen, the National Museum of Antiquities, Stone Foundation and the National Cultural Heritage Authority. It shows that for the Doggerland residents in a period of 4000 years the menu, between 9500 and 6000 BC., gradually changed from mostly meat to mostly fish. Especially freshwater fish was eaten a lot, as well as small animals such as otter, beaver and waterfowl.

The study is based on measurements of stable isotopes. These are variations of atoms having a certain value. The value of some isotopes, such as nitrogen and carbon, changes according to the position in the food chain. A real meat-eater has a different isotopic signature than someone who eats seafood or someone in a fresh water wetland.

The detected change in the composition of the Doggerland menu is associated with the drowning landscape between the Netherlands, England and Denmark, after the last ice age. Between 9500 and 6000 BC. the climate warmed and sea levels rose on average about two meters per century. That is about ten times faster than today.

The low-lying North Sea basin was filled with water. Previously it was thought that this drowning of land and the rising waters forced residents further inland, or forced them to specialize in a marine diet. The isotopic measurements showed that they were eating more fresh water fish. This suggests, according to the researchers, that the people were not scared away, but rather continued to live in the vast wetlands which then arose in the deltas of Meuse, Rhine and Thames. Precisely because it was a nice place and one could find enough food.

Treasury of our coast

The bone material which is used for the isotope analysis is taken from the North Sea. Since the last few years there have been many prehistoric findings there. The material is not only retrieved with fishing nets but is mainly found in the reclaimed sand for coastal defenses and major projects such as the Second Maasvlakte and the Zandmotor. This sand comes from the North Sea floor and contains the remains of a vast and largely unexplored prehistoric landscape. Although research on the spot is awkward, the results show that there is a wealth of data.

Scientists have reconstructed in detail the collapse of the Eurasian ice sheet at the end of the last ice age. The big melt wreaked havoc across the European continent, driving home the original Brexit 10,000 years ago: here.

Breakthrough in studying ancient DNA from Doggerland that separates the UK from Europe: here.

Great cormorant flock


This video from the jetty in IJmuiden in the Netherlands shows a great cormorant flock on the North Sea.

Dutch North Sea reef underwater wildlife, video


This 16 September 2016 is about the Dutch North Sea reef Borkumse Stenen, its fish, tube worms, soft coral, sea anemones and other underwater wildlife.

Humpback whale near Dutch coast, video


This video is about the humpback whale, swimming near a pilot boat off the Hook of Holland Dutch coast, on 1 January. The whale continued its journey to the north-east.

Orcas in the North Sea, video


This video says about itself:

11 October 2015

Ship in North Sea surrounded by Killer Whales.

Young sturgeon found again in North Sea


This video shows Atlantic sturgeons (Acipenser sturio) in the Trocadéro aquarium in Paris, France.

Translated from the ARK conservationists in the Netherlands:

Thursday, September 10th, 2015

Almost three months after having been released in the Rhine one of the marked sturgeons was captured by a shrimp trawler in the North Sea. The shrimpers have reported their catch to Sportvisserij Nederland, WWF and ARK Nature. The rare sturgeon after the catch was put back in the water alive.

Marked sturgeon

The European sea sturgeon (Acipenser sturio), 78 centimeters in size, was caught on Thursday September 3 about four o’clock off the coast of Goeree-Overflakkee, about 15 kilometers from the Haringvliet sluices. The sturgeon was equipped with a mark with contact data in case of being caught. After measuring, recording of data and taking a picture, the sturgeon was put overboard in good condition by the crew of the VLI-7 Eben Haëzer from Flushing.