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By Alexander NyarkoYeboah – GITFIConline.com
The United Nations Environment has warned that fishing trawlers, seaweed farming, and tourism is threatening the survival of seagrassesoff the coast of Kenya.
This means that the about 12 species of seagrasses distributed along the Kenyan coast covering an area of about 317 km2 faced depletion if care was not taken.
This was made known to the gitficonline.com when it came across an interview Lillian Daudi, a Scientist of Kenya Marine and Fisheries Research Institute (KMFRI), granted to Moina Spooner from The Conversation Africa about the state of seagrasses along Kenyan seacoasts.
Madam Daudi observed that disturbing the sediment on the seabedaffected the meadows, which suffocated the seagrass, or they damaged the seagrass by trampling it, indicating that there were also natural disturbances, such as grazing by sea urchins, which had led to the total loss of seagrasses in some areas.
She added that, “Overgrazing, in particular by the collector sea urchin, has been a major factor in how seagrass is distributed along the Kenyan coast. This is because there’s been a fast rise in sea urchin populations which I believe is due to overfishing. Fish, such as the parrot fish, are the natural predators of sea urchins,”
Madam Daudi informed that when urchin populations were high, they moved in aggregations and could clear seagrass shoots at the rate of five shoots per day per urchin, and that in Kenya, they had been reported to have moved in aggregations of up to 137 urchins per 10m², consuming huge amounts of seagrass.
The scientist saidKenya lost about 21% of its seagrass cover between 1986 and 2016 with the intensity and frequency of seagrass loss varies along the coastline. “Some areas show signs of natural recovery while others have become altered habitats with a different composition of seagrass species,” she said.
Madam Daudi said the disturbance of seagrass meadows had caused fragmentation of continuous seagrass beds and that these shallow ecosystems supported most artisanal fishermen along the Kenyan coast, providing important habitats for fish, including rabbit and seagrass parrot fish.
She said that these losses might, in the long term, affect the dynamics of the food webs, especially the fish supported by these meadows, such as parrot fish.
Madam Daudihowever observed that several efforts were being made to protect seagrasses by indicating that the KMFRI had been conducting research on seagrasses over the last decade, which supported the activities of various organizations responsible for the protection of seagrasses.
“For five years, there have been efforts to protect seagrasses through restoration trials carried out by the Kenya Marine and Fisheries Research Institute. These trials provided data on the best species to use, the most cost effective ways and implications of restoration efforts. These trials are important to recolonize areas that have lost grass and increasing meadows. So far, the one that’s shown the greatest success involved planting seagrass seedlings in punched holes in large bags on the ocean floor.
“Kenya’s seagrass rehabilitation efforts are commendable and contributed to the development of seagrass ecosystem restoration guidelines for the Western Indian Ocean region, supported by the United Nations Environment Programme.There are also encouraging signs from government as there are currently efforts to review and implement the national coral reef and seagrass conservation and management strategy.”
She however observed that there were still some challenges when it came to managing and protecting seagrasses, “because we’re still not sure of the distribution and actual cover estimates of seagrass along the coast. This requires sound techniques such as remote sensing and remotely operated vehicles that are now underway to enable mapping and monitoring of changes to seagrass beds over time. Until this happens, there’s no certainty about which conservation strategies do or don’t work.”
That notwithstanding, she indicated that the future was bright since the capacity in seagrass research had grown over the years, especially as more scientists had developed passion for exploring these unique habitats.
Seagrasses are flowering marine plants that have adapted to survive in marine conditions. They are mostly found in shallow sandy bottom habitats and can form dense extensive meadows.
There are about 72 seagrass species distributed across the world’s temperate and tropical oceans. These meadows trap sediment, absorb nutrients and give us clear waters.
They are a source of food, shelter and nursery areas for many organisms, including commercially important fish. This means that they provide food security for coastal communities by supporting artisanal fisheries and are an integral part of coastal livelihoods. They also support a number of endangered species such as dugongs, sea turtles and sea horses.
Seagrass meadows are also important carbon sinks, capable of trapping carbon from the atmosphere 40 times faster than tropical rainforests and storing it for hundreds of years.