That is a pair of green, rather large diameter 'mooring ropes' that are permanently attached to the white buoy,, and the other end is transferred to the containership's bow bollards, when the containerships of length more than 350 m are moored alongside the berth :-))
When a large containership is not at the berth, the other end of the green mooring ropes is gathered & tied on the quay (as can be seen on this photo).

Emmanuel,, I do hope to have well explained the "line/wire" you have mentioned in your comment;
Remaining with very best regards,
Jadran

Lovely sunny weather, clear blue sky, but "autumnly cold" temperature (9 °C)... picture taken at 9:37 LT morning hours :-))

Many thanks for your well observation of this photo and for your kind comment, Clyde!
Greetings from the autumn Rijeka,
Jadran

What is that line/wire between the famous white buoy and the quay Jad?
regards
Emmanuel.L.(Malta)

Lovely reflections on the lee side Jadran. And beautiful middle of the day (?) blue sea.

.... yes, she's of medium size (166 m length) let so be said ... and I much like her "fresh" green tone hull colour (compared to the "weird" red-brownish hull colour of AS Venus - IMO 9127514);
Many thanks for the really nice comment, Volker my friend!
Cheers /Jadran

PS: .... "and in the foreground" .... is the *famous* big White Buoy... hehehe

Hello Jadran.Fine shot of this medium sized vessel.And in the foreground the ......... Cheers Volker