University of Southampton OES Undergraduate Falmouth Field Course 2016 - Group 3 databank and initial findings.
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Van Veen Grab
The Van Veen Grab gave a partial ground-truthing
for a small area of zone 3. The grab retrieved
Saccharina latissimi among coarse sediments
chiefly composed of crushed shell. These are the
two principle characteristics of Zone 3. Grab fauna
included
- Leocarcinus spp. from the swimming crabs
- Nucula nucleus, a small saltwater clam
- Tapes Decusstus; the grooved carpet shell (a commonly aquacultured clam and important bio-indicator
However, the majority of bivalve indiviuduals identified (Nucula nucleus & Tapes decusstus) were deceased.
Our findings showed us that the area we surveyed was very uniform in terms of the habitat. It showed the substrate in Zone 3 as being composed of coarse sand and shell fragments with a medium density of Maerl. The seafloor was also scattered with Saccharina latissimi, a large fucoid kelp. Zone 2 was dominated by rocky outcrops, however these were not distinct areas and it was hard to identify boundaries from the side scanner prints. The green area, named Zone 1, is likely a high density kelp bed. Zone 1 would have been a good area for video survey or grab to provide a ground-truthing for the area. However, due to time constraints, additional grabs and video surveys were not possible.
Video Footage
The video footage collected showed benthic substrate to be composed of mostly coarse sand, Maerl and shell debris. Larger rock bedforms were present providing an attachment site for the main kelp present (Saccharina latissima). This was viewed within both video transects. Lack of living organisms was significant with mollusc and bivalve shells dominating the area viewed. Exceptions included two Raja Clavata, a Marthasterias Glacialis and macro-algae species including Saccharina latissima, Plocamium cartilagineum and Desmarestia sp.
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Habitat Mapping - Observations
Groundtruths proved adequate in confirming Zone 3 habitat. Unfortunately, because groundtruthing in Zone 1 and 2 was prevented due to time constraints, the side scan was the only means of defining zones in the Habitat Track Plot.
Fig. 1. Benthic Habitat track plot West of Black Rock, Falmouth. (21/06/2016)
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