transparent gif


Ej inloggad.

Göteborgs universitets publikationer

Development in a trawl-damaged coral habitat (Tisler reef, NE Skagerrak) during four years of trawl protection

Författare och institution:
Tomas Lundälv (Institutionen för marin ekologi, Tjärnö marinbiologiska laboratorium); Jan Helg Fosså (-); Pål Buhl Mortensen (-); Lisbeth G. Jonsson (Institutionen för marin ekologi); Martin White (-); Damien Guihen (-); Vikram Unnithan (-)
Publicerad i:
4th International Symposium on Deep-Sea Corals, Wellington, New Zealand, December 2008,
Konferensbidrag, refereegranskat
Sammanfattning (abstract):
The Tisler reef is a relatively large (c. 0.25 km-2 live reef, c. 0.5 km-2 total) inshore reef dominated by the hermatypic scleractinian cold-water coral Lophelia pertusa. The reef was first documented by ROV in 2002 and has later been mapped in detail. The mapping revealed that large parts of the reef had been damaged by trawling. The Tisler reef and a small buffer zone around it was protected from fishery with bottom-impacting fishing gear in late 2003. Quite a number of Scandinavian cold-water coral reefs have been protected against bottom-impact fisheries during the last decade. To our knowledge, however, there have been no previous studies to demonstrate the effectiveness of such protection or the rate of recovery in damaged coral habitats after protection. To study these issues, a bottom transect (weighted line with markers) was established through a trawl-damaged part of the Tisler reef in 2005. The development in the coral habitat surrounding the transect was then documented regularly by ROV (video, still photography and video mosaics) over a period of 3 years. Great care was taken to prevent impact of the ROV used on the coral habitat studied. The studies have revealed frequent re-location of smaller coral colonies and fragments. In part of the transect, smashing and re-location of larger colonies was also observed. In a few larger and stable colonies growth rates (increase in polyp length) of c. 6-7 mm-year were measured from time-lapse photographs with laser markers. Our findings indicate that during the study period there was no net recovery in the coral population studied, but instead a net loss and further fragmentation of live coral tissue. It seems likely that part of the negative development was related to continued illegal fishery with bottom-impacting gear, which was further indicated by loss or displacement of bottom-mounted recording instruments deployed withinin the protected area. Also natural factors, such as occasional occurrence of very strong bottom currents (as measured in the area by recording instruments), might contribute to hinder re-establishment of smaller coral fragments created by physical disturbance, due to frequent re-location of the fragments.
Ämne (baseras på Högskoleverkets indelning av forskningsämnen):
Biologiska vetenskaper ->
Ekologi ->
Marin ekologi
Cold-water corals, coral reef, Lophelia pertusa, marine ecology, Skagerrak, Tisler
Ytterligare information:
Oral presentation and abstract
Postens nummer:
Posten skapad:
2009-01-14 13:25
Posten ändrad:
2010-01-26 10:52

Visa i Endnote-format

Göteborgs universitet • Tel. 031-786 0000
© Göteborgs universitet 2007