Our 2015/2016 survey season finished at the end of April 2016 when Peter and Frances followed the swallows back to England.
By the end of April we had completed 2 full assessments on all 14 sites with the help of our willing volunteers – who are now nicknamed the mud larks after getting stuck in a couple of really muddy sites which didn’t dampen their enthusiasm one bit. We have continued to refine assessment methods as we gain more experience. We now take a quarter meter square quadrat for each of the different biota at each site in order to obtain detailed information on population numbers. We have found and identified over 200 species which shows the huge amount of life living in the Estuary and is great indicator of its health. We can now compare the results of two assessments at each site and Frances is spending much of her time in England sorting out the mass of data into some sort of order.
Interesting observations included an explosion in the numbers of shaggy sea hares (Buraetella leachi) in March many of which were found washed up on the shores all round the Estuary. The cause is not known but many were seen to be mating so this may have been one of the reasons for such large numbers. We accessed water data from the KEMP data recorders and found that oxygen levels had been lower than normal at that time and this could also have been a factor. Those who assessed the rock stack at Featherbed Bay were fascinated to watch a large octopus hunting for food along the water’s edge.
The most striking feature of the last year has been the effects of the sheets of sea lettuce (Ulva lactuca) which now cover large areas of the shores especially in the Ashmead Channel and its approaches. This is smothering the eelgrass and mud and affecting the species that normally live there – for example in some areas the mud prawns have almost disappeared. This is turn will reduce their value as nurseries for young fish. However we will have to learn to live with this as the recent paper by Dr Allanson et al, ‘Insights into the cause of an Ulva lactuca Linnaeus bloom in the Knysna Estuary’, suggests that the sea lettuce is unlikely to go away. We have also been dismayed to see the damage to the eelgrass beds in Kingfisher Creek caused by extensive digging by baiters. This is a major threat to Knysna’s environmentally important eelgrass beds which account for half of the eelgrass in South Africa.
Part of the routine of ShoreSearches now is to take plastic sacks with us and collect litter on the walk back from the assessment site which is particularly valuable in the more remote areas where official litter pickers do not reach. Sadly we usually find just as much litter when go back a few weeks later.
ShoreSearchers are fully involved in Knysna Basin Project’s education programme with local and visiting schools, public groups and visiting organisations such as WESSA. We have been particularly involved with Knysna Primary’s Eco Club and Riverwood Primary, and we spent a very worthwhile morning in April introducing new SANParks staff to the life of the Estuary. Our interaction with schools covers the shore and saltmarshes and includes classroom presentations and guided beach and shore walks where pupils are shown the many species living around the estuary and how important it is to treat the estuary and its inhabitants with care and respect. For many it is the first time they have seen how beautiful shaggy seahares are, the casings where moonshine worms live and the many other wonders of the Knysna Estuary.
We start assessments again in early October 2016 and we look forward to renewing contact with our volunteers and another successful ShoreSearch season. The good news is that SANParks have extended our research permit until 2019 which will enable us to further increase our data base of species diversity and frequency and to develop how best to present the data for the authorities and public.
What Is Shoresearch?
The ShoreSearch project started in 2013 with the joint objectives of recording and monitoring the rich diversity of the marine shoreline of the Knysna Estuary and of engaging the public in participating as volunteers in the monitoring programme and learning about the Estuary.
It aims to answer the questions; what is living on or washed up on the marine intertidal shores of the Estuary, how does it compare with what was recorded in the past and how is it changing now. The answers to these questions will help SANParks and the Municipality in their endeavours to preserve and protect the Estuary and contribute to the public’s awareness of its importance.
The project is led by Frances Smith, a graduate from Oxford University, England, and assisted by Peter Smith. The surveys are carried out with the help of volunteers from the general public who are given appropriate training to become ‘citizen scientists’. Engagement with the public started in 2012 with the publication of the booklet ‘A Brief Field Guide to The Common Shore Creatures of the Knysna Estuary’ by Frances and Peter Smith. The inspiration for ShoreSearch came from the Hampshire and Isle of Wight Wildlife Trust in England; Frances and Peter had taken part in Shoresearches organised by them along the coast of the Solent and have (cheekily) adopted their model and name which is ideally suitable for the Knysna estuary. For information on their projects, do visit www.hiwwt.org.uk
The documented information we collect will enable us to create a base line of data on the diversity and number of species that live on the Estuary’s shores now. By comparing it to the pioneering work led by Professor John Day in the late 1940’s and early 1950’s and the surveys carried out by Professor Brian Allanson in 2000 we will be able to show what has changed over the last 60 years. Ongoing monitoring will enable us to document changes as they occur in the future.
The survey will focus on what is visible on the surface of the intertidal zone and will add data to the body of current research and understanding of the Estuary. Current research includes studies by Knysna Basin Project and researchers from Rhodes University, Stellenbosch University, the University of Cambridge, England and the University of Jena, Germany.
Where and When Do We Survey?
We have established 14 sites around the Estuary from the Heads to the Point, including Leisure Isle, and on the western shore from Belvidere to Featherbed Bay. These cover a range of habitats or biota including rock pools, rocky shores, sand, mud, eelgrass and saltmarsh.
Our survey season runs from early October to end April. Surveys are always done close to spring low tide so as much of the shore is exposed as possible. It is hoped that our volunteers will continue surveys during the winter months May to September.
How Are Surveys Carried Out?
The surveys are very simple and easy to learn, take about 2 hours to complete and carried out at three levels:
- Firstly – a walkabout on the shore noting everything that is present to build up an overall picture of all the creatures and plants that are there.
- Secondly – transects across each habitat zone, e.g., rock, sand, eelgrass. We lay a line between low and high tide marks and record everything seen for 2 meters on either side or their frequency.
- Thirdly – we take a quarter meter square quadrat and count everything found in it at each different biome along the transect.
- Participants are provided with species lists and illustrated guides.
How Do I Get Involved?
You do not need to have any knowledge of marine life before taking part in a ShoreSearch survey as there will be experts on hand to help with identification, and you will gain marine biological knowledge of the habitats and species that live on the Estuary’s shores and contribute to building up a picture of the Estuary.
The current programme comprises an extensive range of studies by Knysna Basin Project staff and volunteers and researchers from universities in South Africa and overseas.
Projects include the Knysna seahorse project, ShoreSearch as described above, the eelgrass project – an intensive study programme carried out by Dr Richard Barnes from Cambridge University on the biodiversity of the sub-surface layer of the eelgrass beds with 5 or more papers published or in publication, studies carried out by Dr Alan Hodgson and students from Rhodes University into the truncated mangrove snail recently arrived in the Estuary and into the invasive Mediterranean mussel to name but two, Dr Allanson’s study of the endangered false limpet, Siphonaria compressa, the topically very important investigation into the recent invasion of sea lettuce (Ulva lactuca) – a joint project with the Nelson Mandela Metropolitan University in Port Elizabeth, Project KEMP which is monitoring the quality of water in the estuary through fixed data recording stations and a survey of baiting practices being undertaken by Dr Carol Simon and Alheit Du Toit from Stellenbosch University.
ShoreSearch Bollard Bay and Knysna Heads