Dr Louw Claassens, formerly from the Knysna Basin Project has relocated to Palau and is now a Researcher/Science Officer for the Palau International Coral Reef Center. (Click here to read previous article)
However, Louw is still leading the Estuarine Pipefish research project.
Below is an update on their research work. It is a fascinating read and we are privileged to have critically endangered pipefish in both of our estuaries.
Louw says ‘Our findings have been written up as a scientific journal article and will be published in the Journal of Aquatic Conservation: Marine and Freshwater Ecosystems’.
‘It has been over a year since our last update of our Estuarine pipefish research work and a lot has happened! Since the last update in March 2020, we conducted another survey in July 2020, despite Covid-19 and all the related obstacles. During this third field trip we repeated surveys in the Boesmans, Kariega, Kasouga, Kleinemonde West and Kleinemonde East estuaries. We sampled the same 15 sites in the Boesmans and Kariega estuaries and 3 sites in the Kasouga, Kleinemonde West and Kleinemonde East as the previous surveys in October 2019 and March 2020. This provided us with comparable data sets across three different time periods which allows a robust estimate of the status of the Estuarine pipefish populations in these estuaries. Having longer term data is especially important, seeing that population numbers and habitat extent are dynamic and can change quite a bit over time.
Image 1. Estuarine pipefish abundance in the Boesmans (left) and Kariega (right) estuaries during October 2019, March 2020 and July 2020.
We also received the results from our environmental DNA (eDNA) samples! As a reminder – eDNA refers to DNA that is found within the water and comes from skin cells, mucus and faeces from animals that live in the water. By collecting and filtering large amounts of water, we are able to collect eDNA which can then tell us which species are present in the environment. We wanted to find out if eDNA can be used to detect the Estuarine pipefish and if this sampling approach would be better at detecting pipefish, compared to conventional seine net sampling.
To do this we also collected eDNA samples at 15 sites in the Boesmans and Kariega estuaries and at 3 sites in the Kasouga, Kleinemonde West and Kleinemonde East estuaries during our October 2019 survey. The samples travelled to Australia with our collaborator and after a long wait we finally have some results! Firstly, we determined that eDNA can detect the Estuarine pipefish and that this is a good additional sampling approach to use to monitor the pipefish. Additionally, we found that eDNA is much better at detecting the pipefish compared to seine netting! In fact, eDNA detected the pipefish at 15 of the 30 sites (50%) sampled in the Kariega and Boesmans estuaries. In comparison, seine netting detected the pipefish at a total of five sites (16.6%) across the two estuaries.
Image 2. Successful detection of the Estuarine pipefish using seine netting and eDNA.
As we continue our efforts to conserve the Estuarine pipefish, we are developing various educational resources that will be shared with the Kenton-on-Sea community. The Recovery Action Plan for the pipefish will be developed within the next few months and will hopefully provide a roadmap for the successful conservation of this iconic species. In addition, we are planning to get back to the field in the next year! This time we will venture up the east coast to survey additional estuaries using both seine netting and eDNA. The aim here is to see if the Estuarine pipefish might be found in additional estuaries along the South African coast.
In addition – Louw has develop an educational overview of their research. Click here.