Search bioRxiv⌕ Search

bioRxiv · 10.1101/2021.05.13.444019

Distant water industrial fishing in developing countries: A case study of Madagascar

Abstract

As industrial vessels continue to expand in both extractive capacity and spatial range, concerns have grown over foreign industrial fishing occurring within the marine territories of developing countries, both legally and illegally. Madagascars status as a "least developed country", coupled with its high marine biodiversity, makes its waters particularly susceptible to fishing by distant water fishing nations (DWFNs). However, given constraints in management and research, it is unclear how foreign industrial fishing, both legal via foreign agreements and illegal, may impact local marine resources that many coastal communities depend on for food security, cultural meaning and livelihoods. We used satellite-derived fishing effort data from 2012-2020, via Global Fishing Watch, to analyze industrial fishing effort occurring within Madagascars Exclusive Economic Zone (EEZ). We documented 907,643 hours of industrial fishing within the Madagascar EEZ across 277 vessels from 17 different countries. We found that Taiwanease vessels (39.8%) using drifting longlines and Malagasy (17.2% shrimp trawlers were the most prevalent. Fishing effort was highly seasonal (68% of effort between October and February) and increased with higher global fish prices and the Indian Ocean Dipole, which is a measure of regional water temperature cycles. We also found a number of instances (17.6% of the fishing effort for 170,726 total hours) of foreign fishing vessels operating close to shore and within a number of marine protected areas. These results highlight the need for increased transparency surrounding foreign fishing agreements and unauthorized fishing within the waters of developing countries. Increases in industrial fishing effort and encroachment into near-shore areas has the potential to severely threaten current sustainable fisheries management initiatives by conservation organizations and coastal communities. HighlightsO_LIDistant water fishing nations dominated fishing efforts within Madagascars EEZ. C_LIO_LILonglining by foreign nations was the dominant fishing mode and increased from October-February. C_LIO_LIMalagasy vessels focused on trawling for shrimp. C_LIO_LIFishing effort increased during positive Indian Ocean Dipoles and with higher fish prices. C_LIO_LIDistant water fishing nations frequently fished close to shore and sometimes within MPAs. C_LI

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

White, E. R., Baker-Medard, M., Vakhitova, V. K., Farquhar, S., Ramaharitra, T. T.. 2021-05-15. Distant water industrial fishing in developing countries: A case study of Madagascar. https://doi.org/10.1101/2021.05.13.444019

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

KEEP EXPLORING

Related preprints

Phenotypic variation in divergent mitochondrial haplotypes in migratory three-spined stickleback

Mitochondria are essential components in life-sustaining organismal processes. The mitochondrial genome can be influenced by selection, and divergent mitochondrial haplotypes have substantial potential to affect interspecies variation in life-history and physiology, yet little is known about whole organism phenotypic changes that might accompany mitochondrial genomic divergence. Three-spined stickleback on the Scottish island of North Uist provide a model to study this as their populations exhibit a well-mixed nuclear genome, yet two highly diverged mitochondrial haplotypes ( trans-Atlantic and European). Three-spined stickleback were sampled from six lochs to investigate associations between mitochondrial haplotype and phenotypic traits including organ size, body size, and ovule volume/clutch size, as well as citrate synthase enzyme activity. Results showed that mitochondrial haplotype has an influence on male gonadosomatic index (GSI) and potentially citrate synthase (CS) enzyme activity. Differences in male GSI may be explained by the timing of male spermatogenesis or potentially a need for larger testes in European haplotype fish. While no other phenotypic trait showed differences between mitochondrial haplotypes, there were many differences between sexes and populations e.g. in body size and organ/muscle size.

ecology↗

Gregariousness can promote invasion success of pest insects while higher environmental heterogeneity decreases it

Climate change and environmental homogenization are expected to facilitate the expansion of many forest pest insect species and increase the vulnerability of forest ecosystems to insect outbreaks. At present, we lack empirical data on how the antipredator defence traits of pest insects interact with the local environmental conditions and shape outbreak risk. Here we study this and ask 1) how the antipredator defence strategy of pest insects shapes survival under naturally varying predator community, and 2) how is predation risk shaped by the diversity and structure of forests? We tested these questions by conducting a field predation experiment with artificial prey system (prey items made from edible dough) where we manipulated the gregariousness, unpalatability and defensive colouration of prey and tested their effects on prey survival. Additionally, we measured environmental variables and invertebrate predator community structure along the prey transects to analyse how they shape overall predation risk. Our results show that the predation risk was always lowest for gregarious prey irrespective of other defence strategies. Furthermore, our results indicate that predation pressure was lower in more homogenously structured forest areas or areas with a weak quality deadwood continuum in comparison to locations with more natural state forests and good quality deadwood continuum. Altogether, our results suggest that gregariousness can facilitate pest insects to form outbreaks by increasing their survival against generalist predators. However, by maintaining higher heterogeneity in forests, it is possible to ensure higher predation pressure to regulate their population growth.

ecology↗

Two decades of EU pesticide substitution have not reduced impacts on stream invertebrates

Chemical regulation assumes that withdrawing hazardous substances and replacing them with alternatives reduces environmental harm. We tested this premise within the EU pesticide regulatory framework using a 23-year record of event-driven pesticide exposure and stream-invertebrate communities from 152 German agricultural streams sampled between 1998 and 2021. Neither pesticide toxic pressure nor pesticide-related invertebrate impairment showed a detectable decline over time, and an improvement equivalent to one ecological status class can be excluded. Dominant toxicity drivers shifted from organophosphates to neonicotinoids and subsequently to pyrethroids, yet the relationship between toxic pressure and community effects remained consistent despite their distinct modes of action. Sustained toxic pressure reflected three mechanisms: successive chemical substitution, prolonged approval periods, and continued exposure to substances no longer authorised as plant protection products. Substitution thus changed which chemicals harm streams, not how much. Measured field outcomes must become the benchmark of pesticide regulation.

ecology↗