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A boat throttles through thick sargassum in Owia in July 2018. (iWN photo)
A boat throttles through thick sargassum in Owia in July 2018. (iWN photo)
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By Kimani Wiseman

Climate change and the massive invasion of sargassum seaweeds are “villains” to the fisheries sector. They partner like Two-Face and The Riddler in the movie “Batman Forever”, with a mission to destroy. Climate change refers to significant changes in global temperature, precipitation, wind patterns, and other measures of climate that occur over several decades or longer.

Climate change is accelerated when there is an increase of greenhouse gases in the atmosphere — such as carbon dioxide, nitrous oxide, methane, sulphur dioxide — that warm the earth. The ocean absorbs more than 90% of the heat trapped on earth from increased green house gases, and a study published in January 2019 in the journal science, reports that the oceans are warming 40% faster on average than the UN predicted five years earlier, and ocean temperatures continue to break records year after year.

Warmer waters can make some fisheries smaller by putting metabolic stress on fish, making it harder for them to reproduce or find food. It can also cause zooplankton, essential fish food, to decline. It also threatens to cause mass migration of marine species in search of the right conditions for feeding and spawning. This would have a negative impact on fisher folks because it would cost them more gasoline to go further out in the sea.

The largest reef in the world, the Great Barrier Reef, is experiencing coral bleaching. Coral Bleaching refers to the process in which a coral colony loses zooxanthellae, the microscopic algae, when under some form of environmental stress. As zooxanthellae is expelled, the coral colony appears white, hence the term “bleached”. A CNN news article on Aug. 8, 2018, states that in 2016 and 2017, marine heat waves caused by climate change resulted in mass bleaching which killed about half of the Great Barrier Reef. Ocean acidification also occurs as a result of an increase in carbon dioxide in the ocean. The more acidic the ocean is, it is harmful to sea creatures like oysters, corals, plankton, and shellfish that grow hard shells made of a chalky mineral called calcium carbonate. If ocean water becomes too acidic, it can begin dissolving those shells.

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Here are some solutions for climate change:

  • Plant more trees: Trees remove carbon dioxide from the atmosphere during photosynthesis.
  • Use more renewable energy such as solar, wind, etc., and less fossil fuel.
  • Purchase energy saving bulbs and electrical appliances.
  • More recycling and composting should be done. This would alleviate a lot of garbage going to the landfill, which would mitigate a lot of methane emitted.

Methane absorbs the sun’s heat, warming the atmosphere hence the reason it is considered a green house gas. Methane is particularly problematic as its impact is 34 times greater than carbon dioxide over a 100-year period.

  • Fuel efficiency vehicles should be utilised more, and they should be made more affordable to attract people to use them.

Sargassum is a genus of large brown seaweed (a type of algae) that floats in the ocean and never attaches to the sea floor. Sargassum is invading a lot of beaches in the Caribbean and it is causing a crisis on the fisheries sector. Scientists have some theories about the invasion of the sargassum seaweeds in the Caribbean. These include the rise of water temperature and the change of sea currents due to climate change. Also, nutrients from agricultural fertilisers and wastewater from cities that end up in the sea could also make the algae flourish.

An invasion of sargassum smother sea grasses and coral reefs, it tangles up fishermen motors, engines, nets, and their lines. Nesting sites for turtles can be blocked. In 2015, over 40 sea turtles died in Barbados after they became “entangled” in large mats of seaweeds.

Here are some solutions for sargassum:

  • In Indonesia a man name David Christian has invented biodegradable food packaging made from seaweed.
  • In St. Lucia, one entrepreneur is turning seaweed into plant tonic, while in Barbados a fertiliser project is already taking place. Sargassum has a nutrient content of about 1- 1.5% nitrogen, 0.5 – 1.5% phosphorous, and 1- 2% potassium. It can also be used as mulch and for compost. It must be noted that before using seaweeds: it must be washed properly to remove all the salt, and also tractors should not be used to remove the seaweed. Using tractors would remove a lot of the sand from the beach. Seaweed is very important for the marine ecosystem, it provides food, refuge and breeding grounds for animals such as fishes, sea turtles, marine birds, crabs, shrimp, but when there is a massive invasion, it causes problems.
  • Composting can be done which would alleviate the usage of synthetic fertilizers. Sargassum seaweeds have essential nutrients that plants need; this can also help to mitigate some of the synthetic fertilizers that are used.
  • Wastewater can be treated and reused for irrigation in farming; households can use it for bathing, flushing toilet, etc., in the event there is a water shortage from a drought.

Don’t you think in the Caribbean, more persons should get on board and turn all these seaweed into something profitable, instead of having it destroying all these pristine beaches?

4 replies on “The effects of sargassum, climate change on fisheries”

  1. Ricardo Francis says:

    Where are the ships and or boats coming from, that is dumping this stuff in our waters at nights?

    Where are the seaweeds coming from?

    Did it just come out of the water?

    Where in our living history have we ever had this type of seaweed before? Tell Me!

    Please think outside of the box!

    Is it not the same way that Mayreau was separated?

    It is believed that the sand in Mayreau was mined at nights.

    Climate change is a hoax and those who advocate it, will do anything to make us believe that it is real.

    God save us all!

    I am very fearless and courage.

    Ricardo Francis, Prime Minister of St. Vincent and the Grenadines in Waiting and in the Making

  2. More and more reports keep coming out that the climate is mainly driven by the sun’s activity, (even though this has been known or suspected for over 500 years). Last week NASA came out with a very revealing study that has already been announced by other scientific entities that the wobble, or tilt of the earth is also more of a cause of Climate Change lately than it normally has been. NASA and other entities say the Climate cycles normally last approximately 11 years.
    There has never been a realistic study that provides any evidence that CO2 has any effect whatsoever on the climate. I challenge the author to provide any REAL evidence whatsoever on how CO2 effects the climate. Until the author of this article can do that he is just propagating misinformation put out by the Global Establishment, (those greedy politicians, bankers and the fossil fuel industry that fund the Climate Change Agenda).
    Anyone reading this article and my comment is encouraged to do thier own research and not be a “useful idiot” of those wanting to get more of your money under the guise of “saving the planet” while at the same time destroying the environment. CO2 is a vital molecule needed to sustain life on earth. If the CO2 levels were quadrupled it would still have NO NEGATIVE effect on the climate. Instead we have to reject the GMO trend that contributes to destroying the bee populations (they have known this since the 1970s) and we have to reduce real pollution.

  3. The Caribbean Sea is overused. Pollution caused by excessive tourism will result in another Mediterraneanlike phenomenon. Over harvesting of the marine life will make it unsustainable. We are witnessing rise in the ocean level and temperature. There is a need to protect the Caribbean Sea ecosystem.

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