The global phenomenon of climate change, including its repercussions on Yemen, has undeniably left a lasting imprint on the marine environment, endangering the rich array of marine species that define the unique ecosystem of the Red Sea. Bassel Obaid, a seasoned 39-year-old fisherman hailing from the picturesque shores of Al Hodeida Governorate, candidly shares his observations with Khuyut on how environmental transformations have impacted the time-honored fishing profession. With rising temperatures triggering coral bleaching, the ripple effect is keenly felt by both local fishermen and the marine life they rely on for sustenance.
"The consequences of coral bleaching on migratory species like barracuda and sedentary residents such as grouper have become starkly noticeable. The surge in temperatures is instigating profound shifts in the underwater landscape, directly influencing the abundance of fish in our customary fishing zones," articulates Obaid, drawing attention to the intricate balance disrupted by environmental stressors.
Coral reef habitats are celebrated for their remarkable biodiversity, serving as vital sanctuaries for a diverse array of marine species. These underwater ecosystems are home to more than 25% of the global marine species diversity
Urgent Environmental Challenges
This environmental impact is not the sole challenge facing fishermen in Al Hodeida. There are urgent environmental challenges, such as the threat posed by the giant oil tanker Safer, which has caused significant concern, according to Obaid, due to oil leaks and petroleum waste from it. "We have witnessed a noticeable decrease in the Arabian fish population in the area surrounding Safer, to the extent that they have completely disappeared, as evidenced by the red color of the sea water, a result of the petroleum waste that has spread to affect a wide marine area."
In a related context, Ja'afar Ba Omer, Assistant Professor of Coral Reef Environment at the College of Environmental Sciences and Marine Biology at Hadramout University, states that coral reef environments are among the most biodiverse ecosystems on Earth, containing over 25% of marine biodiversity. Ba Omer further explains to Khuyut: "Coral colonies play a vital role in providing food and shelter for many fish and invertebrates, as well as serving as an ideal location for mating and reproduction. Therefore, the impact on coral reefs and colonies threatens marine life in general, causing marine organisms to migrate to other environments in search of shelter and food."
Moreover, Rashidi Mahmoud, an esteemed specialist in fish research and guidance studies at the Ministry of Agriculture, Irrigation, and Fisheries Wealth, underscores the critical role of coral reefs as they provide intricate structures that not only offer secure shelters for a diverse range of reef fish and large predators but also serve as vital ecosystems supporting marine life. These reefs play a crucial role in maintaining biodiversity by providing a safe haven for various species and contributing to the overall health of the marine environment.
In a conversation with Khuyut, Rashidi elaborates: "Fish choose to lay their eggs in the tranquil and protected environment of coral reefs, facilitating successful reproduction and the growth of juvenile fish. The coral reefs not only support a rich marine ecosystem but also play a significant role in enhancing the diversity of fishery resources. They serve as habitats for over 25% of all marine fish species, which are fundamental for ensuring the long-term sustainability of fisheries."
Despite covering only 1% of the vast marine expanse, coral reefs are home to over 25% of marine biodiversity, thriving in shallow waters within tropical and subtropical regions between the latitudes of 30 degrees north and 30 degrees south, as confirmed by Dr. Ba Omer. He highlights the intricate symbiotic relationship between the coral animal, responsible for reef construction, and single-celled algae known as zooxanthellae. The coral provides a sanctuary for the algae, supplying them with carbon dioxide and nitrogenous waste from metabolic processes, while the algae, through photosynthesis, provide the coral with organic matter as a food source and contribute to building the coral's calcareous structure.
Moreover, Dr. Ba Omer underscores the vulnerability of coral animals to environmental changes, thriving within a specific thermal range of 15°C to 36°C, with the most favorable temperature range for growth and reproduction being 24°C to 28°C. Coral reefs flourish in clear, nutrient-poor waters, typically found at depths that permit sunlight penetration while avoiding turbidity caused by sediment runoff from rivers. This strategic positioning ensures the optimal conditions necessary for the health and vitality of these intricate marine ecosystems.
The occurrence of coral bleaching arises when coral animals endure harsh and precarious environmental circumstances, notably substantial temperature fluctuations that surpass the coral's threshold of tolerance.
The Phenomenon of Coral Bleaching
In light of the uncertainty surrounding the specific effects of climate change on local ecosystems, scientists have commended the resilience of coral reefs in adapting to varying water temperatures. Dr. Ba Omer explains: "Coral bleaching occurs when coral animals are subjected to severe and critical environmental conditions, primarily notable temperature fluctuations that exceed the coral's tolerance limits. These changes affect the symbiotic relationship with zooxanthellae algae, responsible for the coral's vibrant color. As the algae depart from the coral colony due to adverse environmental conditions, the coral turns stark white, leading to bleaching and eventual coral death due to food scarcity."
In addition, Ba Omer confirms the presence of six genetic strains of zooxanthellae algae that coexist symbiotically with coral, each strain differing in its resilience to challenging environmental conditions. Consequently, the coral's capacity to endure temperature variations varies depending on the genetic strain of the associated algae
Ba Omer further remarks: "Coral reef environments have experienced a notable decline in coral populations, with a 14% decrease over the past decade attributed to bleaching. Nonetheless, the Red Sea reefs demonstrate remarkable resilience to environmental shifts, despite high salinity and summer temperatures. The incidence of coral bleaching in the Red Sea is significantly lower compared to other marine regions. This has sparked growing interest in the potential of Red Sea reefs to serve as a sanctuary for preserving coral reefs in other seas if global coral environments continue to degrade."
The study conducted by the Regional Organization for Marine Environmental Protection, titled "Adaptation of Coral Reefs to Climate Change for the Year 2023," underscores the escalating threat posed to coral reefs in shallow coastal marine areas due to rising temperatures, increasing the susceptibility to bleaching events. Additionally, the study highlights the adverse impact of local pressures from activities such as desalination, wastewater discharge, and coastal construction on the resilience of corals. These factors contribute to heightened heat stress, degradation of coastal water quality, and elevated turbidity levels, further endangering the delicate balance of marine ecosystems.
Moreover, the study emphasizes the dynamic challenges faced by central and outer marine regions, fueled by the influences of seasonal winds, upwelling currents, and the amplified occurrence of hurricanes. These environmental factors significantly impact the coral's ability to withstand such changes. The study warns of the severe consequences of intensified wind and wave forces, depletion of dissolved oxygen in water, increasing acidity levels, and the proliferation of harmful algae, all of which collectively pose a substantial threat to the survival and well-being of these vital coral reef habitats.
The disposal of domestic and industrial wastewater, which includes waste materials and chemical residues like coal, anti-fouling paint, and other chemical compounds, into the sea, is a detrimental factor that has serious repercussions on the health and well-being of coral reefs.
Additional Human-Induced Stressors
The study highlights that coral reefs face not only the impacts of climate change but also additional human pressures that coincide with these changes. These combined pressures result in direct coral loss and hinder their ability to adapt to the challenges posed by climate change.
Dr. Yahya Falous, an esteemed Associate Professor at the Faculty of Marine Sciences and Environment, specializing in Marine Biology and Fisheries at Al Hodeida University, underscores the significant factors that gravely affect coral reefs amidst rapid urban development and expansion. Of these factors, the discharge of domestic and industrial wastewater containing harmful substances like coal, anti-fouling paint, and various chemical compounds into the sea emerges as a notable threat.
In his discussions with Khuyut, Falous further emphasizes, "Overfishing presents yet another formidable threat, leading to the depletion of crucial species within the ecosystem, disrupting the delicate environmental equilibrium and ultimately harming the coral reefs. Indiscriminate harvesting of marine organisms, without due consideration for the potential harm inflicted upon coral reefs, can precipitate their decline."
"The utilization of unsustainable fishing practices, such as employing dynamite and sodium cyanide (a potent and rapidly lethal substance that hampers cellular respiration and oxygen utilization), directly inflicts severe damage upon coral reefs. Regarded as one of the most perilous activities jeopardizing marine ecosystems, these methods not only endanger fish but also result in the demise of coral, fish larvae, and various other invertebrates. Over the past two decades, more than a million kilograms (equivalent to 1100 tons) of sodium cyanide have been utilized, a quantity substantial enough to cause the demise of approximately 500 million individuals on the planet" as detailed by Falous.
Thus, it is essential to recognize that bleached coral reefs are not entirely lifeless but are vulnerable to diseases and malnutrition. Should water temperatures swiftly revert to their natural levels, there is a potential for recovery through the restoration of symbiotic algae residing within their tissues, unless prolonged bleaching persists and recurs.
The decline of coral reefs in the Red Sea can be attributed to the phenomena of bleaching and the adverse effects of fishing activities. Numerous vessels operating in the region contribute to the fragmentation of coral reefs by employing anchors to moor the boats, alongside congregating boats in reef zones, resulting in their destruction and ultimate demise.
Coral bleaching presents a significant danger to the economic well-being of coastal communities, especially impacting fishermen whose livelihoods suffer as they are compelled to venture farther distances in search of fish.
Coral Bleaching Threatens Coastal Communities in the Red Sea
The marine environment in the Red Sea is facing an increasing danger. The coral reefs there are likened to rainforests due to their astonishing biological diversity. Coral bleaching signifies the destruction of this diversity and the loss of habitats for countless organisms, including a variety of fish species like groupers and snappers, as well as invertebrates such as shrimp, sea cucumbers, sea urchins, and turtles.
The repercussions of this threat exacerbate the economic crisis in Yemen. "Coral bleaching poses a serious threat to the livelihoods of coastal communities, particularly impacting fishermen who are forced to travel long distances to find fish, leading to increased fuel and labor costs. Additionally, it poses a danger to industries reliant on coral reefs," says Falous.
In conclusion, and in order to preserve biodiversity and coral reefs in the Red Sea, environmental professors, advisors, and experts in the field suggest the necessity of reducing climate change factors. This includes enhancing efforts to cultivate coral strains that can withstand high temperatures, rehabilitating deteriorating marine environments, improving water quality, and implementing sustainable fishing practices through careful planning and zoning to minimize negative impacts. Effective management of marine protected areas is also recommended to allow coral groups to recover, along with the utilization of techniques like coral gardening and cultivation to enhance reef recovery.
