bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2021.01.14.426682

Local ecological knowledge, catch characteristics and evidence of elasmobranch depletions in Western Ghana

Seidu, I.·Brobbey, L. K.·Danquah, E.·Oppong, S. K.·Beuningen, D. v.·Dulvy, N. K.
View original source ↗Export metadata ↓

Abstract

Local Ecological Knowledge has the potential to improve fishery management by providing new data on the fishing efforts, behavior, and abundance trends of fish and other aquatic animals. Here, we relied on local knowledge of fishers to investigate ecological factors that affect elasmobranch fishers" operations and the changes in stock status of sharks and rays from 1980 to 2020 in five coastal communities in Ghana. Data were gathered from fishers using participant observation, interviews, focus group discussions, and participatory rural appraisal techniques. The results revealed fisher"s understanding of six main ecological variables, which are mostly applied to enhance their fishing operations: season and weather conditions, lunar phase, bait type, presence of seabirds and fish movement, color of seawater, and sea current. These ecological features have been applied over the years to enhance fishing operations as well as maximize fisher catch. Fishers reported a profound decline in shark and ray catch from 1980 to 2020 and attributed the decline in size, number, and composition of their catch to overfishing and Illegal, Unreported and Unregulated (IUU) fishing operations. In general, most shark and ray species were abundant in 1980 but have been severely depleted as of 2020, with the exception of Blue Shark (Prionace glauca) and Devil rays (Mobula spp), which were reported to be common by the interviewed fishers. The first species depleted were the Thresher sharks (Alopiidae), Tiger Shark (Galeocerdo cuvier), Blackchin Guitarfish (Glaucostegus cemiculus), and Lemon Shark (Negaprion brevirostris), which were depleted early in the 2000s. The next depletions of Hammerhead sharks (Sphyrnidae), Bull Shark (Carcharhinus leucas), Sand Tiger Shark (Carcharias taurus), Stingrays (Fontitrygon spp), and Spineback Guitarfish (Rhinobatos irvinei) occurred in the 2010s. We found Local Ecological Knowledge of fishers to be surprisingly consistent with scholarly knowledge and call for their inclusion in research, decision-making and management interventions by biologists and policy makers.

Explore related subjects

zoologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Seidu, I., Brobbey, L. K., Danquah, E., Oppong, S. K., Beuningen, D. v., Dulvy, N. K.. 2021-01-16. Local ecological knowledge, catch characteristics and evidence of elasmobranch depletions in Western Ghana. https://doi.org/10.1101/2021.01.14.426682

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

A baseline for aquatic parasite diversity in West African mangroves: host-parasite records, DNA barcodes, and an experimental design for future use

Macroparasites represent a major fraction of biodiversity and biomass in marine ecosystems, yet remain substantially underrepresented in ecological surveys and food-web models, particularly in the Global South. This study addresses this geographic bias by providing the first comprehensive ecological survey of macroparasite communities of fishes in a West African Marine Protected Area (MPA) and adjacent Open-Access Area (OAA) characterised by mangrove forests. We collected 5,020 parasite specimens from 10 fish and one crab species in the Saloum Delta, Senegal, identifying 27 parasite species across all major taxa. Our findings include 15 new records for Senegal of which 11 are also new for West Africa. Additionally, 64% of host-parasite combinations constitute new host records. We provide 208 DNA barcodes, offering the first molecular data for 31% of these species globally and establishing a reference library for future DNA metabarcoding efforts in the region. Using sample size-corrected biodiversity indices and mixed-model analyses, we detected significant variations in parasite infracommunities and component communities between the MPA and OAA, demonstrating the feasibility of using comparative study designs to monitor fisheries impacts on parasite diversity in the Saloum Delta. Furthermore, the identification of trophically transmitted parasites provided evidence of unstudied food-web connections, e.g. predator-prey linkages between fishes and higher-trophic-level definitive hosts including birds and elasmobranchs. By integrating morphological identification, molecular data, and archiving of voucher specimens into publicly accessible, curated collections, this study establishes a new baseline for marine parasite biodiversity in West Africa and provides a methodological blueprint for surveying understudied regions.

zoology↗
bioRxiv2026

Sea slugs unplugged: Review of subpopulation sampling in phylogeographic studies of nudibranchs and their allies

Nudibranchs and other sea slugs include many cryptic species groups with unknown phenotypic and ecological diversity. How broadly and deeply should researchers sample those cryptic species pairs to capture the genetic variation within each species and potential adaptive differences between species? Fast and inexpensive surveys of genetic diversity that sample a single well-known locus across the geographical range ("phylogeography unplugged") have long been used to identify structured populations and guide choice of sampling localities for subsequent comparative genomic or phenotypic studies of the same species. Results from such studies might also be used to better understand the expected relationships between sampling and population structure in future comparative studies in other species (including many marine gastropods) for which an unplugged phylogeographic survey is not available or impractical. We reviewed analyses of molecular variance that used mitochondrial barcode sequences from marine sea slugs, and we asked whether there are characteristic patterns of subpopulation sampling that are associated with the magnitude and geographical scale of differentiation. We found wide variation in sampling designs: studies with both many and few samples discovered significant population differentiation or broadly similar distribution of haplotypes on both large and small spatial scales, in species from different higher taxonomic groups and oceans. We found two significant associations between sampling variables and population genetic variables, and we suggest using those associations to help guide (or understand the consequences of) sampling design in future studies.

zoology↗
bioRxiv2026

A novel methodology for assessing reinforcement choice in primates under human care

Positive Reinforcement Training is a technique commonly employed in zoological collections to elicit a desired behaviour from an animal under human care. Typically, a food item is offered as a reward for performing that behaviour. Three non-human primate species (Mandrillus sphinx, Pan troglodytes, and Hylobates lar) were offered four different foods (banana, grape, apple, and sweet potato) in a series of choice experiments. Latent variable models were employed to investigate which foods were the best selection to use as reinforcement items. Results show that food preference varies between the three primate species. Pan troglodytes and H. lar showed strong preferences for grape and banana, whereas M. sphinx showed a very strong preference for sweet potato. This study indicates that foraging ecology might play an important part in fruit selection and preference in primates. The findings highlight that understanding a species' natural behaviour and dietary preferences is key to informing reinforcement and training decisions.

zoology↗