Onder water in Leiden.nl
LightNews LightNews
banner
owinleiden.bsky.social
Onder water in Leiden.nl
@owinleiden.bsky.social
97 followers 46 following 94 posts
Posts Replies Media Videos
owinleiden.bsky.social
Interessant nieuws vd andere kant van de wereld! Zie ook het vergelijkbare Leidse rivierdonderpaddenhotel uit 2018-2019, www.rhotel.nl
@ravonnederland.bsky.social
@gemeenteleiden.bsky.social
#Leiden #bullhead @numenini.bsky.social @drfishsg.bsky.social
#Stadsgrachten #boostcartoon
a drawing by BoostCartoon depicts a wooden structurele, aka hotel, with various openings. A bullhead (small fish) is lying in front of the entrance and another is on the roof, viewing the scene from above. Small and big pebbles lie scattered around the hotel, to make the environment less muddy. Zebramussels have attached themselves to the roof of the hotel and to some pebbles. two children are feeding the protected bullheads after they have been released into the bullhead-hotel in an urban canal in Leiden, the Netherlands the bullhead hotel is depicted by an in situ photograph and schematic drawing in a text. Questions are asked about the design, function and other aspects about its goal. The questions are part of the CITO examination for 16-17 year old students, like a GCSE (or sophomore, GPA).
October 31, 2025 at 11:09 AM
owinleiden.bsky.social
Even though I don't know them, I feel like I know them! Such distinctive dorsal fins and patches. Thanks for sharing!
We study the same in our fish/reservation in #Leiden, NL.
onderwaterinleiden.nl/mediafotofil...
#smoelenboek
a Dutch newspaper article describes how many fish and other species have been recorded by the CanalCam, a livestream in the fishreservation in Leiden the tail of a big fish, pinkish grey and consisting of two big lobes, is photobombing this screenshot taken by the CanalCam, a livestream in an urban canal in Leiden, the Netherlands a greyish tench, a 65 cm long fish, part of the carp family, is nose down feeding in front of the CanalCam. Its large pectoral fins are spread wide, to give the animal some thrusting power to search deeper into the sediment for macrofauna. The city canal in the background is greenish blue and quite clear. a tench, a carp-like fish, known as Touché, in front of the CanalCam: that's a livestream camera in an urban canal in the fishreservation in Leiden. This individual has three torn up fins, of which the dorsal and anal fin are visible in the picture. the water is greenish blue, the fish a dark brown/grey color.
October 14, 2025 at 6:11 PM
owinleiden.bsky.social
Je boot hozen om hem winterklaar te maken mag *niet* in de gracht, singel, kanaal of rivier: vuil water met brandstof- en olieresten laat je (veelal gratis) afzuigen bij de bilgepomp van de gemeente of Passantenhaven. Koester het waterleven 🤗
September 26, 2025 at 1:50 PM
owinleiden.bsky.social
Zuidsingel Leiden, midden in het visreservaat en op de zoutkistenroute.nl!
#100bruggenloop #singelparkleiden
September 16, 2025 at 4:44 PM
owinleiden.bsky.social
Out of 8 juvenile female clarkii #crayfish, 4 showed visible cement glands (to stick eggs with to their swimming legs). Scary thought: growing numbers of teenage crayfish are getting ready to reproduce
#rivierkreeften @invasieveexoten.bsky.social
September 10, 2025 at 5:06 PM
owinleiden.bsky.social
full body treatment here in #Leiden, in the fishreservation! From april-juni, from perch, rudd an roach fry. And footmassages from adult tench, I kid you not!
September 3, 2025 at 10:33 PM
owinleiden.bsky.social
I have a copy🥳! Hoping to publish about this project (CanalCam Leiden) in the future 🤗
August 28, 2025 at 3:11 PM
owinleiden.bsky.social
...seeing quite a lot of fresh and healing wounds on tench and bream on the CanalCam Leiden right now, hence my interest. (They were all grabbed by a pike, but escaped.) Healing fast = 'clean water'. @hhrijnland.bsky.social @gemeenteleiden.bsky.social
@knnv2ehandsboek.bsky.social @knnv.bsky.social
a dark brown tench amongst yellow water lilly stalks, blind in his left eye, nabbed by a pike on the left flank and showing deep wounds in a whitish colour a dark grey bream showing two pinkish wounds - missing flesh and the subcutaneous fat layer - on his right flank, plus some other small wounds. The result of a pike attack, which this animal survived. the dark brown tench named 'Link' seen from above in the water, with fresh pinkish wounds on mostly the left side of his flank. Green leaves of the yellow water lilly are around and below the animal. a newspaper clipping in Dutch, explaining the lessons learned and some results after three months of livestreaming urban aquatic wildlife on the CanalCam Leiden in the Netherlands. Amongst others pictured by the CanalCam are a mute Swan, Louisiana crayfish and a slider turtle.
August 21, 2025 at 11:15 PM
owinleiden.bsky.social
big shoals of Abramis brama I've only watched from the surface - in the water they're too skittish. Asked around and largest bream caught here was 6kgs, 11y ago. My exp is they don't get larger than 65cm in #Leiden
August 17, 2025 at 12:59 PM
owinleiden.bsky.social
Also very handy for drinks, tools and your finds! Like extra nets, jars, even your phone (in a waterproof pouch). I also take a babybath with me, occasionally
August 16, 2025 at 4:47 PM
owinleiden.bsky.social
Should you maybe start wearing a diving buoy, Nicola? I know it's a hassle underneath the brush you swim through; the Beuchat is the most sturdy I could find. 1/2
August 16, 2025 at 4:44 PM
owinleiden.bsky.social
An adult rudd/rietvoorn/Scardinius erythrophtalmus standing upright for 45 sec. @numenini.bsky.social we only saw this in youngsters before, right?
There was no viz predator/ around.
@visdeurbel.bsky.social
@drfishsg.bsky.social
@knnv2ehandsboek.bsky.social
#CanalCamLeiden
July 17, 2025 at 7:12 PM
owinleiden.bsky.social
Great shots anyway of the snacking pike, Nicola! Well done. I managed it once in ten years of snorkelling; also a jack pike (here reenacted in an aquarium setting)
July 6, 2025 at 3:04 PM
owinleiden.bsky.social
'hanging' perch fry, seen on the CanalCam Leiden very early this morning. I couldn't spot a predator lurking about, but it could have easily been a bigger perch.
onderwaterinleiden.nl/mediafotofil...
July 2, 2025 at 12:04 PM
owinleiden.bsky.social
Does anyone have a suggestion what this growth on the rudd's throat area can be?
The footage was caught on the CanalCam Leiden, in the NL.
#fishreservation #CanalCam #Leidencity

youtu.be/93pSjh5XuGk?...
July 1, 2025 at 10:04 PM
owinleiden.bsky.social
June 30, 2025 at 6:46 AM
owinleiden.bsky.social
de meeste schildpadden in Leiden (centrum) zijn geelbuik, zaagrug/onechte landkaart en kruisingen 3/n
June 14, 2025 at 5:27 PM
owinleiden.bsky.social
ook al zijn het invasieve exoten, zich succesvol voortplanten doen ze nog niet (al zijn eitjes met embryo's wel in stadsparken aangetroffen) #ravon
@invasieveexoten.bsky.social 2/n
June 14, 2025 at 5:25 PM
owinleiden.bsky.social
It reminds me of the smaller, burrowing and chewing family members depicted in Primeval primeval.fandom.com/wiki/Sid_and...
June 10, 2025 at 4:49 PM
owinleiden.bsky.social
Tench Bami and André, and in the background Maid Marian and Amadeus (with the postules on his bum)
June 6, 2025 at 7:14 PM
owinleiden.bsky.social
here's a clip
June 4, 2025 at 3:30 PM
owinleiden.bsky.social
does someone recognise this goby? It's a first on CanalCam Leiden. We have seen: round, tubenosed and Caucasian dwarf
(and endemic bullheads, almost extinct).
June 4, 2025 at 3:27 PM
owinleiden.bsky.social
Lots more #fish spawn than in previous years in urban canal, thanks to frazzled feline lifelines and overhanging plants: space to lay eggs an hide from predators. #urbannature #CanalCamLeiden #Leiden
May 20, 2025 at 11:18 AM
owinleiden.bsky.social
Opgevist door onze kanoënde vrijwilliger Randalf, in de Oude Haven van Leiden: gehaakt kinderpopje met vleugels en folder over #DuurzaamVaren van de @gemeenteleiden.bsky.social 😁
#Leiden #duurzaamheid #grachtwacht #waaivuil
May 19, 2025 at 11:07 AM
owinleiden.bsky.social
Zeer schadelijk voor de onderwaterecologie, deze speedboot in het visreservaat in #Leiden.
#visreservaat #vaarveilig #stadswater #blauwestadsnatuur #ecologie @martinevanschaik.bsky.social
May 16, 2025 at 2:52 PM