These tend to be adhoc arrangements around Barbate and south and several boats have come a cropper in them. They are not marked on the charts as they vary each year.
The nets are laid in the same places every year. The are marked by cardinal buoys, with lights, and the RCC Atlantic Spain and Portugal gives the positions of the more important ones, such as Barbate. The rest may be avoided be keeping about 5 miles offshore.
Navtext advises of their deployment and withdrawal, and the first withdrawal of the year has been posted, presumably because the efficiency of the system has killed most of the fish already.
Station: SPAIN TARIFA
Message type: Navigation warnings covering the station's area
Message id: GA03
24 1209 UTC MAY 07
COASTAL WARNING
NR1270/2007
IMPORTANT
GIBRALTAR STRAIT
ENSENADA DE CEUTA.- FOLLOWING LIGHTBUOYS MARKING AGUAS DE CEUTA TUNNY
NET, RE-ESTABLISHED:1.- E CARDINAL LIGHTBUOY (NUMBER 72400), IN PSN: 35-52.8N 005-18.8W.
2.- S CARDINAL LIGHTBUOY (NUMBER 72405), IN PSN: 35-52.4N 005-18.7W.
Station: SPAIN TARIFA
Message type: Navigation warnings covering the station's area
Message id: GA73
29 1113 UTC JUN 07
COASTAL WARNING
NR1555/2007
IMPORTANT
GIBRALTAR STRAIT
TUNNY NET ENSENADA DE BARBATE, ESTABLISHED TO COLLECT FROM EAST, MARKE
D BY FOLLOWING LIGHTBUOYS:1.-E CARDINAL LIGHTBUOY (NUMBER 20016), IN PSN: 36-09.9N 005-55.4W.
2.-N CARDINAL LIGHTBUOY (NUMBER 20017), IN PSN: 36-10.7N 005-55.5W.
3.-W CARDINAL LIGHTBUOY (NUMBER 20018), IN PSN: 36-09.3N 005-56.0W
4.-S CARDINAL LIGHTBUOY (NUMBER 20019), IN PSN: 36-08.2N 005-55.6W.
Station: SPAIN TARIFA
Message type: Navigation warnings covering the station's area
Message id: GA46
19 1032 UTC JUN 07
COASTAL WARNING
NR1475/2007
IMPORTANT
SPAIN SW COAST
EL PALMAR TUNNY NET, REMOVE WORKS IN PROGRESS, IN VICINITY PSN: 36-14
.5N 006-08.5W.---------------------------------------
And these ones are from Straits Sailing handbook 2007, positions are for 2005 so not this years positions:
2Nm south of Cabo Rocha
West Cardinal 36deg14.3'N 006deg08.8'W
south cardinal 36deg14.0'N 006deg08.5'W
marks are small vessels with vertical poles identifiable as cardinals - this looks like the one with remove works in process from navtex.
Zahara Atun, 5Nm SE of Barbate
West Cardinal at 36deg07.4N 005deg52.3W.
Perpendicular to shore.
Net at Anse Bolonia
SOuth Cardinal at 36deg03.8'N 05deg46.8'W
Not lit.
0.6Nm NW of Tarifa.
west cardinal at 36deg00.7N 5deg37.2W.
Haven't included any east of Gibraltar. Which part of Morroco are you thinking of? I'm thinking about a trip to Tanger in the near future (Chipiona today), may catch you there.
They are supposed to be marked with cardinal bouys and lights, not all are. Earlier this year, the Barbate one, for example, was missing a light when we were there earlier this year. There was also just up the coast was a substantial collection of yellow bouys around an fishing research area. The swell made it hard to see until almost on top of it. Nowt on the chart, but it did show up on the plotter. Makes night passages fun doesn't it!