Vulnerable marine megafauna in the ECAO region
REDUCE focuses on the Eastern Central Atlantic Ocean (ECAO), a region encompassing diverse ecosystems and high biodiversity. This area is critical for numerous threatened marine megafauna species and serves as a vital resource for local and international fisheries.
Types of Fisheries
REDUCE addresses a variety of fisheries operating in the Eastern Central Atlantic Ocean (ECAO). These fisheries use different methods and target diverse species, each with unique bycatch challenges:
1. Pelagic Trawl
Midwater cone-shaped nets towed by a single vessel. The nets are kept open by otter boards and rigging, allowing for large catches.
Target Species: Small pelagics like sardines, mackerels, and horse mackerels.
Bycatch Risks: Sharks (e.g., hammerheads, makos), rays, sunfish, marine mammals (e.g., dolphins, pilot whales), sea turtles, and seabirds.
Fleet: Predominantly EU fleets from Lithuania, Latvia, the Netherlands, Germany, and Poland.
Fishing Zones: Primarily waters off Morocco under CECAF agreements.
2. Purse Seiner
Trapezoid-shaped nets used to encircle and capture schooling species. Nets can reach up to 2,000 meters in length and 300 meters in depth.
Target Species: Tuna species (e.g., skipjack, yellowfin, bigeye).
Bycatch Risks: Larger fish, rays, sharks (e.g., silky sharks, hammerheads), sea turtles (e.g., olive ridley, loggerhead), and seabirds (minimal interaction).
Fleet: Primarily operated by Spain and France
Fishing Zones: Gulf of Guinea, West Africa, and CECAF waters.
3. Drifting Pelagic Longline
A float line suspends a mainline with secondary lines and hooks targeting pelagic and semi-pelagic species.
Target Species: Swordfish and blue shark.
Bycatch Risks: Protected sharks (e.g., shortfin mako, thresher), minimal marine mammal interaction, and occasional sea turtles (e.g., loggerhead, leatherback).
Fleet: Operated by Spain and Portugal.
Fishing Zones: ICCAT and CECAF waters.
4. Demersal Trawl
Cone-shaped nets towed along the seabed, targeting fish and crustaceans living near the ocean floor.
Target Species: Hake, horse mackerel, octopus, and shrimp.
Bycatch Risks: Deep-water sharks, rays, minimal interaction with sea turtles and seabirds.
Fleet: Predominantly Spanish vessels.
Fishing Zones: CECAF waters off Angola, Morocco, Mauritania, Senegal, and Guinea-Bissau.
1. Pelagic Trawl
Midwater cone-shaped nets towed by a single vessel. The nets are kept open by otter boards and rigging, allowing for large catches.
Target Species: Small pelagics like sardines, mackerels, and horse mackerels.
Bycatch Risks: Sharks (e.g., hammerheads, makos), rays, sunfish, marine mammals (e.g., dolphins, pilot whales), sea turtles, and seabirds.
Fleet: Predominantly EU fleets from Lithuania, Latvia, the Netherlands, Germany, and Poland.
Fishing Zones: Primarily waters off Morocco under CECAF agreements.
2. Purse Seiner
Trapezoid-shaped nets used to encircle and capture schooling species. Nets can reach up to 2,000 meters in length and 300 meters in depth.
Target Species: Tuna species (e.g., skipjack, yellowfin, bigeye).
Bycatch Risks: Larger fish, rays, sharks (e.g., silky sharks, hammerheads), sea turtles (e.g., olive ridley, loggerhead), and seabirds (minimal interaction).
Fleet: Primarily operated by Spain and France
Fishing Zones: Gulf of Guinea, West Africa, and CECAF waters.
3. Drifting Pelagic Longline
A float line suspends a mainline with secondary lines and hooks targeting pelagic and semi-pelagic species.
Target Species: Swordfish and blue shark.
Bycatch Risks: Protected sharks (e.g., shortfin mako, thresher), minimal marine mammal interaction, and occasional sea turtles (e.g., loggerhead, leatherback).
Fleet: Operated by Spain and Portugal.
Fishing Zones: ICCAT and CECAF waters.
4. Demersal Trawl
Cone-shaped nets towed along the seabed, targeting fish and crustaceans living near the ocean floor.
Target Species: Hake, horse mackerel, octopus, and shrimp.
Bycatch Risks: Deep-water sharks, rays, minimal interaction with sea turtles and seabirds.
Fleet: Predominantly Spanish vessels.
Fishing Zones: CECAF waters off Angola, Morocco, Mauritania, Senegal, and Guinea-Bissau.
Taxons
REDUCE focuses on mitigating the impact of bycatch on four key taxonomic groups in the Eastern Central Atlantic Ocean (ECAO). These groups are particularly vulnerable to fishing activities, and their conservation is essential for maintaining marine biodiversity and ecosystem balance.
Sea Turtles
Sea turtles, including the loggerhead (Caretta caretta), green (Chelonia mydas), and leatherback (Dermochelys coriacea), are among the most affected species by bycatch in the ECAO. These marine reptiles face significant threats from interactions with fishing gear such as gillnets, pelagic longlines, and artisanal equipment. Bycatch often targets juveniles and adult females, which are vital for reproduction, severely compromising the long-term survival and population viability of these species.
Marine Mammals
Marine mammals, such as dolphins (Stenella frontalis, Tursiops truncatus) and larger cetaceans like the sperm whale (Physeter macrocephalus), are also significantly impacted by bycatch. Entanglement in drifting nets and purse seines leads to injuries and fatalities, while underwater noise from fishing operations disrupts their feeding, migration, and reproduction behaviors. These combined threats pose serious challenges to their recovery and the ecological roles they play in marine ecosystems.
Seabirds
Seabirds, including shearwaters (Calonectris edwardsii, Puffinus puffinus) and the northern gannet (Morus bassanus), are particularly vulnerable to pelagic longlines. Attracted by baited hooks, they often become entangled, leading to high mortality rates. This decline in seabird populations not only threatens their survival but also disrupts the balance of marine food webs, where they play a crucial role as predators.
Sharks and Rays
Sharks and rays, such as short fin mako (Isurus oxyrinchus), silky shark (Carcharhinus falciformis) and various demersal rays, can be affected by bycatch, depending on the fishery, the area and the season, due to their high mobility. These species may be by-caught and with high discard rates, what can exacerbate the population decline. As apex predators,
their loss causes significant disruptions to marine ecosystems and trophic dynamics.