Kelp Survey Sept 25

Gerrans Bay Marine Group report

The group has been quiet over the summer months. However, we conducted two citizen science surveys on September 10th taking advantage of a very low tide. The first was the Big Seaweed Search, which is an annual survey that is now in its 9th year. We combined with Wild Roseland members, and were 10 surveyors in all. We survey the same part of the rocky shore at Porthcurnick every year to chart changes over time in the presence and abundance of 13 species of seaweed chosen to be indicators of ocean warming, ocean acidification and the spread of invasive species. This year we noted that bladder wrack is much less abundant than in previous years and harpoon weed (an invasive species) is more abundant. The Big Seaweed Search is a nation-wide survey coordinated by the Museum of Natural History.

We also conducted a kelp survey at Porthcurnick on September 10th. This is also coordinated by the Natural History Museum and looks at the status of kelp around British shores. At the moment we can only access kelp on the shore, and even that is only uncovered at very low water. We measure four, meter square patches of kelp, recording the number of plants and the length of the longest plant in each patch. Most of the kelp seen during the survey was oarweed, but we also saw a few plants of furbelows kelp. Our next kelp survey is at Porthcurnick on Friday November 7th. We will meet at the Rosevine slipway at 1215, ready to start the survey at low tide at 12.30. Volunteers are welcome.

The next meeting of the Gerrans Bay Marine Group will be held at Gerrans Memorial Hall Meeting Room from 6pm on Thursday 6th November. Anyone interested in the natural wellbeing of Gerrans Bay is welcome to come.