Artisanal fisheries catch highlights hotspot for threatened sharks and rays in the Republic of the Congo

Abstract

Global catch rates of sharks and rays from artisanal fisheries are underreported, leading to a lack of data on population status. This forms a major barrier to developing effective management plans, such is the case in Central and West Africa. Over 3 years, we undertook the first systematic quantitative assessment of sharks and rays landed by an artisanal fishery in the Republic of the Congo. During 507 sampling days (mean 14 surveys per month), we recorded 73,268 individuals. These comprised 42 species, of which 81% are considered at an elevated risk of extinction. Landings were dominated by immature individuals, especially for species of conservation concern. Presence of species thought to have largely disappeared from the region such as the African wedgefish (Rhynchobatus luebberti) and smoothback angelshark (Squatina oculata) suggest Congolese waters are a potential stronghold for these species—warranting increased protection. We identified seasonality of catch within years, but not across years. Both inter‐ and intra‐annual trends varied by species, signifying annual fluctuations in catch of each species but consistent catch of all species year‐on‐year. Analysis showed increased catch between the short‐wet and the long‐wet, and the long‐dry seasons (January–February and August–September). Lowest catch was shown to occur during the short‐wet and the short‐dry seasons (October–December), which may provide an opportunity for seasonal closures or gear restrictions.

First records of Mobula hypostoma (Bancroft, 1831), Atlantic Pygmy Devil Ray, (Myliobatiformes, Mobulidae) and other devil rays in shallow waters of the Republic of the Congo, Gulf of Guinea (West Africa)

“…Mobula thurstoni was photographed in September 2005 in the Republic of the Congo (Pointe Noire), and M. mobular was photographed in August 2004 at the surface in deep offshore waters on the border of Angola/ Democratic Republic of Congo (Weir et al 2012). A recent study analysing artisanal fisheries highlighted that the Republic of the Congo is a hotspot for threatened sharks and rays (Doherty et al 2023). Although the catches mainly involved endangered sharks, five species of Mobula were identified: these were mainly M. thurstoni and M. mobular, but they also included M. hypostoma, M. tarapacana, and M. birostris (Doherty et al 2023).…”

“…A recent study analysing artisanal fisheries highlighted that the Republic of the Congo is a hotspot for threatened sharks and rays (Doherty et al 2023). Although the catches mainly involved endangered sharks, five species of Mobula were identified: these were mainly M. thurstoni and M. mobular, but they also included M. hypostoma, M. tarapacana, and M. birostris (Doherty et al 2023). However, there was no information on the natural habitat of the captured species available without positional data to certify as to where the rays had been caught.…”

“…Couturier et al 2012), it is likely that populations in the northern part of its range have been heavily impacted and have been fished to near extinction. The Congolese government is currently planning the creation of three new marine protected areas (representing 12% of its EEZ; Doherty et al 2023). The government is also revising current fisheries laws (Doherty et al 2023), which will aid the protection of marine biodiversity and fisheries resources.…”

“…The distribution of the East Atlantic population of M. hypostoma is poorly known, and the population is likely substantially depleted by overfishing (e.g. Ward-Paige et al 2013;Doherty et al 2023). The species has been confirmed for Angola, Cape Verde, The Gambia, Guinea, Guinea-Bissau, Mauritania, Sao Tome and Principe, Senegal, Sierra Leone, and Western Sahara (Marshall et al 2022).…”

Fisher perceptions of catch and trade of sharks and rays in Angolan small‐scale fisheries

“…Momballa, 2020;Seidu et al, 2022b). Furthermore, a systematic quantitative assessment of sharks and rays landed by an artisanal fishery in the Republic of the Congo highlights that this region is a hotspot for threatened sharks and rays (Doherty et al, 2023).…”