My past twenty years of research work at sea involved taking along bins of equipment -glassware, chemicals, oceanographic instruments, batteries and spares for everything. So, walking down to the Keurbooms Estuary for this month’s seahorse survey with all my sampling gear inside a small rucksack, feels minimalistic to say the least.
The 50m Research vessel has now been replaced by a canoe, and with my family as crew we set off on an ebbing tide to search for Knysna seahorses, albeit in the Keurbooms Estuary. This is one of the few localities other than Knysna, that this endangered species calls home.
Figure 1: The Keurbooms seahorse team paddling to a sampling site.
Four sites have been chosen based on previous research studies in the Keurbooms River system, local knowledge and my own exploration. Sampling at these sites began in February 2018 and will continue monthly over the next year. Additional spot surveys along the whole system are carried out to establish the distribution of the Knysna seahorse within the estuary.
Figure 2: The surveys are done at low tide in water shallow enough for snorkelling.
This work is being done under the auspices of the Knysna Basin Project and will complement studies in the Knysna Estuary by Dr Louw Claasens, our resident seahorse expert, who inspired me to start this work under her knowledgeable guidance. Thanks to her dedicated work which makes use of the latest technologies including remote cameras and VIFE tagging we now know more than ever before about this species.
Figure 3: Basic measurements such as length, sex and habitat of the seahorses is recorded during the surveys.
Figure 4: Camouflage is an effective way of avoiding predators, here a seahorse is well hidden in a patch of dead eelgrass.
The aim of the Keurbooms study is to extend the scientific database on the distribution of seahorses within the Keurbooms River Estuary, and on their relative abundance and home range at specific sites. This information is required as a basis for recommendations on management measures such as seahorse reserves within the Keurbooms Estuary. The answers we need don’t come easily or quickly as the river system is very dynamic as demonstrated by the 2007 flood. Hopefully this project will contribute to the understanding and conservation of this red data species.
Post written by Kathie Peard
