Sea Grass Survey

Conserving our Oceans with

For Universities, Researchers, Interns, Schools, Divers, Volunteers & Conservationists

The ethos behind Open Ocean Science Centres are ‘citizen science’ projects. Volunteers are drafted in to carry on research started by Universities and to continue with the data collection which will be fed back, thus carrying on the research which would otherwise be impeded by a lack of continuity. One such project, was to measure a sea grass bed which has recently grown in the Open Ocean House Reef, Abu Sauatir. We were asked if we would like to take on the sea grass project, and indeed we were, so me, Gerald Taylor and my 13 year old son, Finlay, began the planning. We both had the prerequisite diving skills – Finlay in fact, despite his age, came to Roots with 100 dives already under his belt. It was a month long exercise at Roots that would give Finlay, who has an exceptionally keen interest in the underwater world, real life experience working and living in a foreign country, and an understanding of marine biology project work. Coupled with the project, Finlay worked with the marine biologists at Open Ocean carrying out fish and coral ID and measuring / monitoring techniques. The objective of the project set was to measure the perimeter/extremities of the sea grass within the bay and to gain an understanding of its shape, distribution, density and what lives within it. Together we formulated a method by which we would be able to measure the perimeter of the sea grass. The starting point then was to undertake land based measuring techniques using 50 meter transects and quadrats, with the full knowledge that stretching a tape underwater to a distance of nearly 50 meters would have its complications. Two methods of measurement were undertaken. The first was a depth analysis – to assess the shallowest and deepest depths of the seagrass and range of its growth. This also incorporated the width of the sea grass at given depths. Following on from this, because a meter depth range is not the same as a linear meter in distance, we measured the linear distance between the depth markers to get the gradient. From the data collected, the shallowest sea grass occurred at 11.5 m depth on the given day of measurement; the deepest sea grass was at 17.5 m depth. Markers were placed at each meter depth interval in-between. The linear distance between the shallowest and deepest growth at 11.5 and 17.5 meters deep was 23 meters, and from this we found out that the greatest linear distance was between 13.5 and 12.5 depths - 10 meters long – not only the shallowest gradient but also the area of most growth. The width of the growth at 13.5 meters depth was 30 linear meters wide. Due to the natural inaccuracies associated with the use of depth, we approached our second measurement method. We started by using the widest part of the sea grass at the 13.5 m depth marker, determined from the previous study and used the centre of this to create an x-y axis. We marked out and laid a horizontal line (the x axis) and 90˚ to this we laid a vertical line (the y axis). We had now divided the sea grass patch into four quadrants, labelled Q1, Q2, Q3 and Q4. For each quadrant, we put markers in the ground at changes in direction – as our brief was to measure the perimeter / extremities of the sea grass. At each marker, we obtained dimensions on both the x and y axis, ensuring the measuring line was kept at 90˚ to the tape measure at all times to guarantee as much accuracy as possible. Once the data had been collected within the four quadrants – that is the position of markers at 70 different points, we could graphically represent each quadrant. Following on from this, we carried out a density analysis within each quadrant – placing quadrats in random positions, making notes of the positions for future comparison, and taking photographs. We also assessed the visible life within each quadrant. Amazingly, the sea grass, although perhaps only 25 mm tall, had already attracted ghost pipe fish, making it abundantly clear how ecologically important the grass is and how certain species are naturally drawn to habitat within it. With the exercise complete, this benchmark study was been forwarded to Open Ocean and the information is now accessible to all volunteers and visiting University students. The aim is for volunteers and researchers to compare and contrast this data over time and to ascertain whether the sea grass is expanding or contracting. In doing this, comparable data will be obtained over the years to monitor the health of the sea grass and the fauna that lives within it. Gerald Tayor 2nd Nov 2023 Summary of the depth method, which gave us an indication of the width of the sea grass and growth extremities.

Open Ocean @ Roots Red Sea, kilo 14 safaga Road, El Quseir, red Sea, Egypt info@openoceanproject.org