From Coral to Catch: Coral Reef Fisheries in the Red Sea

Despite covering just 0.1% of the ocean's surface, coral reefs provide critical habitats for at least a quarter of the world’s fish species . Catches from coral reef fisheries provide essential protein and mineral intake for over 400 million people worldwide[1]. In the Red Sea, they contribute to food security and livelihoods for communities in the most populous countries bordering it, in particular Egypt, Saudi Arabia and Yemen[2].

This article discusses the ecological, economic, and cultural importance of coral reef fisheries in the Red Sea. It also highlights their role in local communities, the challenges they face from overfishing and habitat destruction, and potential sustainable practices and technologies to mitigate these impacts.

The Ecosystem Engineers: Corals

Corals are soft-bodied marine animals (called polyps) which live in large colonies. Some corals (hard or stony corals) produce a rigid skeleton of calcium carbonate (limestone) structures which form reefs that can stretch hundreds or even thousands of kilometers. The limestone structures built by corals constitute a base upon which their ecosystems rely. Some reef-associated fish species depend on live corals for food (feeding directly on coral polyps) and shelter (as juveniles or adults)[4],[5],[6]. Once corals die, they get colonised by turfs of algae (filamentous dense algae) which get grazed by herbivorous fish species1. Another important role of coral reefs is that they serve as sites for spawning aggregations where fish assessable in large numbers at specific times and specific locations with the aim of reproduction[7] .

As ecosystem engineers, coral reefs recycle nutrients within their ecosystems, allowing them to sustain high productivity even in areas with low productivity, such as the Red Sea[3].

The Unique Environment of the Red Sea

The Red Sea, nestled between Africa and the Arabian Peninsula, is characterized by high air and sea temperatures, high salinity and high evaporation rate and low precipitation. The Red Sea is also characterized by low productivity due to a lack of nutrients runoff from land and limited vertical mixing in the water column. Despite these challenging environmental conditions, the Red Sea boasts a remarkable diversity of fish species (more than 1,400 fish species), thanks to its connection to the Indian Ocean through Bab Al Mandab strait in the south3. Although the Red Sea covers only 0.12 % of the global ocean, it accounts for 6.2 % of global coral reefs[8].

Artisanal Fisheries: A Way of Life

Fisheries in coral reef areas target several different fish species rather than specific species due to the high diversity of fish in those areas. Coral reef fisheries are artisanal (traditional) in nature utilising:

• Small and mostly motorised boats 6-10m long which can easily navigate shallow coral reef areas up to 20m of depth; and

• Traditional fishing gear including hook and lines, gillnets, traps, longlines and spears.

Fisheries statistical data for the entire Red Sea from 1950 to 2010 show that artisanal fisheries were the dominant sector accounting for 49% of the total catch compared to industrial fisheries (large fishing vessels using trawls and purse seines) which only accounted for 22%[3].

Traditional fisheries in the Red Sea catch commercially important species associated with coral reefs, such as groupers (Serranidae), emperors (Lethrinidae), snappers (Lutjanidae), jacks and trevallies (Carangidae), parrotfishes (Scaridae), surgeonfishes (Acanthuridae), and kingfish Carangidae). Other types of fisheries that could be found in the Red Sea are demersal (targeting fishes living and feeding on the sea floor such as snappers) and pelagic (targeting fishes living in the open sea such as tuna and mackrell). Figure 2 shows two examples of two commercially-important coral reef fish groups in the Red Sea namely groupers and parrotfishes.

Coral reef fisheries in the Red Sea are deeply intertwined with the history, traditions and cultures of local communities located along the Red Sea coasts. There is a strong tradition, shared by the maritime cultures of Red Sea countries, where part of the catch is expected to be given freely to family, friends and people who need assistance[3]. Also, traditional fishing methods and knowledge about the reefs and fish aggregations are passed down through generations. At the Farasan Islands in the southern Red Sea of Saudi Arabia, local islanders and tourists gather for several days every year to celebrate the annual arrival of large aggregations of Longnose Parrotfish (locally known as ‘Hareed’ fish) which migrate from the entrance of the Red Sea towards the north. They stop in the shallow waters around Farasan Islands for spawning and those who are not trapped or harvested continue their journey northwards along the Saudi coast to somewhere near Jeddah[7]. The Hareed festival attracts visitors to the Island and showcases the rich history and culture of the Farasan Islands and gives an opportunity for residents to sell their traditional handicrafts. 

Sustainability Challenges

Coral reef fisheries worldwide are facing significant threats due to growing human populations and the corresponding overfishing pressures and the use of unsustainable fishing methods. A study in 2023 estimated that most coral reef fish stocks (accessible to exploitations) were currently compromised in comparison to reference points. These studies were aimed at maximising long-term production[9]. Other major threats facing coral reef fisheries are habitat destruction (due to coastal development and pollution) and the global decline of coral reefs due to coral bleaching[10].

To assess the sustainability of coral reef fisheries, it is important to assess the status of their fish stocks. A ‘stock’ is defined as a set of exploitable fishery resources at a certain instant or period of time[11]. Fish stock assessments provide essential data required to estimate the optimum fishing levels or Maximum Sustainable Yield (MSY), which is the largest fish biomass that can be taken (caught) from a fishery stock without causing irreversible harm to the fish stock. Status assessment of a particular fishery stock and the MSY status involves estimating two main components:

• Exploitation rate: using catch data which is the amount of fish exploited by the fisher. This includes amounts unloaded at a dock (landings) and the amounts discarded at sea (discards); and

• Growth rate: using biological data about fish species caught such as age and length. This information is used to estimate reproduction rates (increase in numbers) and growth rates (increase in size).

Excessive exploitation rates for specific fish species (above certain reference points set for each species), indicate fishing pressure[12]. However, maximising exploitation rates is often required to maintain employment and economic growth. It is therefore crucial to achieve the right balance between the maximum exploitation rate which does not compromise the ability of a fish stock to replenish itself.

The unsustainable fishing practice of catching juveniles (i.e. sexually immature individuals) in coral reef fisheries has led to a rapid decline in body size and abundance of commercially-important species such as groupers[13], [14]. Fish market surveys carried out at the largest fish market on the Egyptian Red Sea coast ‘Sakkala Market’[15] and the two large fish markets of Thuwal and Jeddah in Saudi Arabia[16] collected data about coral reef fishes abundance, biomass, size, price, and potential revenue. Results indicated that both markets are characterised by high diversity and abundance of commercial fish species especially groupers, emperors and parrotfishes. However, higher prices and average sizes are often smaller than lengths at maturity which indicate fishing pressures on those groups of fishes in particular groupers. Figure 3 shows two grouper species displayed at a fish market in Thuwal, Saudi Arabia.

Mitigating the impacts of overfishing should always take into account the impacts on the livelihood of local communities. For example, creation of new economic activities in areas where coral reefs are suffering significant pressures from fisheries can indirectly reduce the impacts of overfishing. A study in the Lingayen Gulf, Philippines shows that promoting eco-tourism and low capital investment aquaculture (e.g. seaweed and sea cucumber) can reduce the pressure on coral reefs as local fishers were willing to switch to these alternative livelihoods[17].

Increasing coral reef protection measures, through restriction of fishing activities, often results in an increase in fish biomass. A study[18] quantified this increase by studying approx. 2,600 tropical reef locations across the world (including the Red Sea) which were subject to different levels of management ranging from Marine Protected Areas (MPAs) where fishing is completely prohibited to areas where fishing is restricted (periodic closures, type of gear and species) and at the other end of the scale, sites that are completely open to fishing. They revealed that management efforts to date have led to an approx. 10% increase in fish biomass and management of sites currently open to fishing could result in additional approx. 10% increase. They also acknowledged that full fishing bans on coral reefs were not feasible because of their detrimental cultural, economic and nutritional effects on local communities.

Current Fishing Technologies and Future Development 

Fisheries in coral reef areas rely on traditional relatively less destructive fishing gear compared to other types of fisheries which use more environmentally damaging methods (such as bottom trawling). It is reported that approx. 75% of artisanal fishing boat landings in the Red Sea are attributed to handlines and gillnets methods[19], [20]. Although they are selective of targeted fish size (mesh size dependent), gillnets are not species selective, and several other species get caught in these nets as ‘by-catch’ including sea turtles, dolphins, sharks, sea birds, dugongs and other species. Another negative impact of gillnets (especially bottom gillnets) is that parts of the net such as weights or anchors, leadline (the bottom line of the net) and the net itself can damage coral reefs and sea bottom habitats. Also the mesh itself can get entangled with coral structures and damage them upon retrieval[21]. Gillnets can become lost in the sea or when damaged they get deliberately discarded in the sea by fishers. This can lead to ‘ghost fishing’ where nets continue to catch fish after being lost or discarded[22].

Technologies and simple gillnet modifications have been developed to mitigate the aforementioned environmental impacts related to gillnets without compromising fish catches. The following are a few examples:

• Research conducted in Manado Bay in Sulawesi, Indonesia [21] showed that the use of bridle line and strapping bands on bottom gillnets can prevent the leadline to be in direct contact with the sea bottom. It was suggested that this modification could drive fish upward and potentially increase catches.

• Modifying the top part of the gillnet using highly visible white multifilament twine as well as adding pingers to gillnets (acoustic alarms) can deter sea birds and accordingly reduce sea birds by-catch without significant reduction in target fish catch[23].

• Acoustic alarms can significantly reduce the chance of marine mammals getting entangled in gillnets.  An experiment[24] conducted at the Bay of Fundy in Canada revealed that installing pingers along the gillnet floatline (upper part of the net) reduces the by-catch rate of the harbour porpoise (dolphin-like marine mammal) by 77% without compromising the catch rates of Atlantic cod fisheries in the area.

• Research and development of biodegradable fishing nets is still ongoing. In order to solve the global issues of ghost fishing. Scientists, engineers, and fishing industry stakeholders are working collaboratively to develop biodegradable polymers with good strength, elongation and stiffness that could replace nylon-based non-biodegradable fishing nets[25].

The advancements and technologies above are based on local conditions and will vary among locations, however, they are likely to be applicable to the gillnet fisheries in The Red Sea.

Conclusions

The sustainability of coral reef fisheries in the Red Sea is crucial for the ecological balance, economic stability, and cultural heritage of the region. While these fisheries provide essential resources and livelihoods, they face significant threats from overfishing, habitat destruction, and climate change. Effective management strategies, including the promotion of alternative livelihoods, the establishment of Marine Protected Areas, and the adoption of innovative fishing technologies, are vital to ensure the long-term health and productivity of these ecosystems. By balancing exploitation with conservation, we can protect the rich biodiversity of the Red Sea and support the communities that depend on its resources.

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