sea – The Pearl Protectors

The Blue Dragon Species

The Pearl Protectors — Thu, 27 Apr 2023 11:04:40 +0000

By Janya Edirisinghe

Glaucus Atlanticus, commonly known as the blue dragon/blue glaucus are a species of nudibranches (sea slugs). However, unlike terrestrial sea slugs, these sea slugs are very brightly coloured. These colours have inspired a series of nicknames, such as blue dragon, sea swallow, and blue angel.

CHARACTERISTICS AND APPEARANCE

The Blue Dragon species is pelagic which means that they float on the water surface, due to the air stored inside their stomachs, which is not a common characteristic of most nudibranchs. The creature often floats on its backside, showing its brightly coloured underbelly to airborne predators. The bright and dark blue colour camouflage against the backdrop of ocean waves, and the animal’s silvery grey dorsal blends in with the bright sea surface, concealing it from predators below. The deep blue colour may also help reflect harmful UV rays. This phenomenon is called countershading where the animal is built in a way to help it avoid being attacked by both flying and swimming predators while floating in open water.

Additionally, the Blue Glaucus has a flattened, tapered body, along with six appendages that branch out into finger-like cerata – they almost look like horns. Cerata are long, slender structures that sting when hunting or when the Blue Glaucus feels threatened.

FOOD AND DIET

Like other sea slug species, the blue glaucus isn’t venomous by itself. They store venom in their bodies mostly derived as they feed on other pelagic, venomous creatures including the Portuguese Man o’ War and the Blue Button Jelly. These sea slugs will then store these toxins within their own tissues. The blue dragon has hard disks inside its skin and a protective layer of mucus that shields them against these stinging cells – of which it can accumulate a significant amount. This ability provides the blue glaucus with a defence mechanism against predation. Cannibalism is also very common between this species – these slugs won’t hesitate to eat other Blue Glaucus if they are unable to find other pelagic creatures to feast on.

HABITAT

Glaucus Atlanticus thrive in warm temperate climates and are usually found in tropical/subtropical waters. These sea slugs are passive swimmers which means that they are carried along by the winds and ocean currents. A group of blue glaucuses floating together is called a ‘blue fleet’. Since they float with the current, these ‘blue fleets’ can end up being stranded in beaches accidentally and they can be found in almost every ocean – there are several records of these creatures being found along Indian coastlines. Humans handling the slug may receive a very painful and potentially dangerous sting, hence it is not advisable to have close contact with these creatures. One thing to keep in mind is that the venom of the Blue Glaucus remains active even after it dies!

Interestingly, Blue Glaucus are now appearing in regions where they have never been seen before and scientists theorize that this may be due to the cyclical changes in the Portuguese Man o’ War populations, warming oceans and increased storm activity.

LIFESPAN AND REPRODUCTION

The life expectancy of the Blue Dragon is short and ranges from between one month to one year.

The Blue Glaucus, like all nudibranchs, is hermaphroditic – each individual produces both egg and sperm. An individual cannot fertilize its own eggs, however, and hence pairs must still mate. Long, spiral-shaped eggs are produced by both males and females and often float freely in the open water or stick to nearby surfaces.

THREATS

Many people want to add these creatures to aquariums all around the world, but keeping the Blue Glaucus in confinement is impractical because of its diet, as it is nearly impossible to obtain the required number of Portuguese Man o’ War, and those kept as pets often starve to death.

Moreover, ocean acidification caused by an increase in C02 levels due to global warming has led to a reduction of food that the Portuguese man o’ war eats (such as shrimp and small adult fish), eventually threatening Blue Glaucus populations.

Additionally, pollution represents an ongoing threat to the survival of Blue Glaucus. Harmful objects can be fatal to this sea slug as well as the toxins in the trash.

As mentioned above, cannibalism is common among this species, so other Blue Glaucus impose a threat to this sea slug. Few studies that have been conducted on the Blue Glaucus, show that loggerhead sea turtles may be one natural predator. A study on this species found that 42% of their stomachs contained remnants of blue dragons.

In conclusion, like most marine invertebrates, there is little information available regarding the conservation status of the Blue Glaucus, therefore, more research has to be done into this area, so that these creatures do not go into extinction.

Rs. 911 million received for X-Press Pearl Compensation

The Pearl Protectors — Fri, 16 Dec 2022 11:29:46 +0000

By Vidusha Sirimanne

On the 20th of May 2021, X-press Pearl, a cargo vessel sailing near the western coast of Sri Lanka caught fire due to a nitric acid leak. More than 50 billion plastic pellets were spilled into the Sri Lankan waters along with other hazardous chemicals, poisoning marine species and devastating the economy of the fisherman in the western coast. This became known as “Sri Lanka’s worst marine ecological disaster”. To prevent further harm, the government imposed an 80 km ban of fishing spanning from Negombo to Kalutara due to fears of contaminated fish entering the local market.

More than a year since the catastrophic incident, compensation payments have been made, initially covering a total of Rs.683 million. In addition, another Rs. 911 million was issued as compensation on 27th August 2022. The payment has been confirmed by the ministry of fisheries and will be distributed to the 15,032 fisherman who were affected by the X-Press Pearl disaster and fishing ban which caused a loss of daily income for months. So far, the money has been received by the impacted fisherman who were awarded a monetary sum of Rs.80,000 to Rs.240,000. However, this does not compensate for the environmental damage and the loss of marine life as there are irreversible consequences that cannot be entirely estimated.

Cover Image: Isuruhetti, Wikipedia

Impact of Climate Change on Fisheries and Aquaculture

The Pearl Protectors — Tue, 11 Oct 2022 10:58:59 +0000

By Nathasha Wickramasinghe

As we move towards the future, our world is changing both positively and negatively. In terms of positive changes, there are major technological advancements. On the other hand, our earth is facing rapid climatic changes resulting in global warming.

Climate change is a global phenomenon which is the long-term/prolonged changes in weather patterns around the world. Climate change is altering biological processes in marine and freshwater fish and their food webs thus having a big impact on fisheries and aquaculture. Aquaculture which is the farming of fish, shellfish, and aquatic plants, has been affected by climate change for over decades. Aquaculture is the fastest-growing food supply sector with an average growth rate of 6.7%. This sector is an integral part of providing basic nutrients for humans.

Image by Govindraj Javali

Rising Sea Temperature

Fish are poikilothermic, which means that their body temperature varies/fluctuates depending on the temperature of the environment. Therefore, temperature plays a vital role in the growth of aquatic animals.

Despite the Paris agreement that came into effect on 4th November 2016 which stated that the collective goal of all the 193 parties that signed the agreement should be to maintain a global temperature of 2c or more (preferably 1.5c), it has not happened yet. So, as the temperature of the water rises due to the accumulation of carbon dioxide, fish will no longer be able to breathe.

Rising sea temperatures also result in thermal stress. Thermal stress is stress that is caused by changes in temperature. Stress has a severe impact on the physiology of the fish which subsequently has a direct impact on their immune system. Corals lose their integral partner which is the marine algae that give the corals their colour and produce food for the coral due to thermal stress. This results in coral bleaching. The Great Barrier Reef, one of the 7 natural wonders of the World, is suffering from coral bleaching. This not only has a drastic impact on aquatic life but also on people who depend on tourism to live.

Changes in temperature also result in nutrient distribution alterations, thus convectional breeding/growing grounds have been altered. This makes it difficult for farmers to catch fish and many fish struggle to obtain the necessary nutrients to evolve and grow to their full capacity.

Rising Sea Levels

With the ongoing climatic crisis, the Intergovernmental Panel on climate change states that the sea level is expected to rise between 10 and 30 inches (i.e. 26 to 77 centimetres) with the temperature warming 1.5c by 2100. But this is expected to change as the magnitude and the rate of the rise depend on greenhouse gas emissions.

A sea level rise will change the composition of species and ecosystem productivity. This rise can also damage aquaculture facilities such as cages, tanks, and ponds, particularly those located in lowland regions.

Sea levels rising can also destroy coastal ecosystems such as mangroves, which are required to protect the coast from coastal erosion, and even salt marshes which are crucial for maintaining fish stock. Damage to these ecosystems could put local people under pressure to move their aquaculture farms elsewhere.

Italian Fish Farmers Association

Ocean Acidification

The ocean is very important to us, not just because it provides various habitats to an eclectic mix of exotic creatures but also because it is the biggest carbon sink to exist on earth. Oceans absorb 50 times more CO2 from the atmosphere than trees on the land. Seaweed (all types) is able to store CO2 for up to a whopping 800 years! Therefore, it is important to ensure the pH levels do not fall, which would result in ocean acidification.

Ocean acidification refers to a decline in pH levels in ocean water resulting from excessive CO2 uptake. A fall in pH level to a critical level will cause water to become too acidic for marine animals and plants to survive thus leading to death. The capacity of the ocean to store CO2 decreases as aquatic plants and other species such as phytoplankton (i.e. the biggest carbon sink) die, thereby exacerbating the state of global warming.

Moreover, a rise in ocean acidity results in a decrease in the availability of carbonate for corals (Carbonate is the building block of corals). Thus, growth declines resulting in the depletion of the natural habitat. This will place much of the aquatic way of life in danger.

Rising acidity can also have a negative impact on the physiology and metabolism of aquatic species but this depends on the adaptive capacity of the species.

Fisheries is a place where fish are grown for food/where they are caught for commercial purposes. The impact of climate change on fisheries can be segmented into two categories.

1. Direct effect

2. Indirect effect

Direct effects are seen in the physiology, reproduction, behavior, and development rates of the fish. Indirect effect act through changes in the ecosystem such as nutrient distribution and availability of species.

Fishery scientists use computer-based models to monitor water temperature/acidification levels. Based on recent data from the models, the carbon dioxide content has rapidly increased, resulting in many fish struggling to survive due to oxygen deprivation. Consequently, the fishery industry will also struggle to meet the demand for fish around the world (demand>supply), thereby resulting in food insecurity.

Image by Paul Einerhand

Poverty and Climate Change

Small-scale fisheries are extremely vulnerable to climate change. There are two factors affecting this:

1. Poverty

2. Location

Many small-scale fisheries are located on waterfronts and so they are exposed to natural hazards fueled by climate change such as coastal flooding, hurricanes, ocean acidification, and coastal erosion. And due to their low income, they are unable to build effective defense barriers to protect fish farms from disasters.

Therefore, many lose their source of income and cannot support their livelihoods. Livelihood strategies may have to be modified with changes in fish migration patterns. This could potentially impose social pressure and major occupational changes.