Marine Research Findings of the VECTORS Project

This website provides access to the research results of the VECTORS project, which can be used to support marine management decisions, policies and governance as well as future research and investment. VECTORS was a large scale project that brought together more than 200 expert researchers from 16 different countries. It examined the significant changes taking place in European seas, their causes, and the impacts they will have on society.

The impact of jellyfish on fisheries and tourism in the Catalan coast

Along the Catalan coast, there has been a perceived increase in the occurrence of jellyfish in coastal waters and beach strandings. The principal drivers of this change, are a combination of increased water temperature (climate change), and reduction in predators and competitors (overfishing)1. This has become of concern to beach managers and local authorities who suppose that tourism could be negatively affected by the strandings. Similarly, recent evidence has demonstrated the predation of jellyfish (Pelagia noctiluca) upon small pelagic larvae2 which could potentially negatively impact the local fisheries’ landings and profits. Given the best available data and modeling techniques, a social-ecological simulation model was constructed to investigate these interactions for various future scenarios over a short term period (10 years) as well as for the medium term (in 2050).


The impact of an increase in Pelagia noctiluca on small pelagic fisheries along the Catalan coast will be low.

A comparison of three scenarios over a decade demonstrate the impact of changes in Pelagia noctiluca blooms on the anchovy (Engraulis encrasicolus) fishery. Compared to the “Expected blooms” (historic data taken from 2000-2010), the “No blooms” scenario landings (as an average over the decade) would be increased by around 294 tonnes per year (5.1%) or approximately 0.19 M€ in profits per year (4.5 %). In the case of “Frequent blooms”, landings are predicted to decrease by around 147 tonnes per year (2.5%) (averaged over 10 years) and decrease profits by 0.10 M€ per year (2.3%). However, it should be highlighted that this finding does not include the impact of Pelagia noctiluca (or other abundant jellyfish) on the sardines (Sardina pilchardus) fishery due to the lack of data regarding predation rates.


The impact of an increase in Pelagia noctiluca on tourism along the Catalan coast will be low.

A comparison of three scenarios over a decade demonstrate the impact of changes in Pelagia noctiluca blooms on summertime strandings. Compared to the “Expected blooms” (historic data taken from 2000-2010), the “No blooms” scenario, strandings would decrease by 49% (averaged over 10 years) from an average 199 to 102 events where at least one beach is affected. In the case of “Frequent blooms”, strandings would increase by 32% per year (averaged over 10 years). According to Nunes et al. (pers. comm.), this would not have a sufficiently large impact on the decision of tourists to change beach, thus the overall economic impact would be zero. However, it should be noted that there are many other non-stinging jellyfish species that become stranded on beaches and this cumulative effect might be enough to pass the threshold in which tourists choose to visit other beaches with fewer jellyfish. Given the paucity in data regarding population, life-cycles and strandings of both Pelagia noctiluca and other jellyfish, further research is recommended.


Medium term (circa 2040) scenario analysis reveals that the “National enterprise” scenario (A2 in the Special Report on Emissions Scenario (SRES)3 would maintain fisheries profits similar to current levels. Whereas “Global community” (B1 in SRES) would reduce profits almost to zero.

A medium term economic analysis, given current levels of in Pelagia noctiluca (“Expected blooms”), was undertaken for various scenarios for the decade 2040-2050. The “National enterprise” scenario (A2 in SRES) supposes a world of independently operating self-reliant nations, an increasing population, and a regionally oriented economic development. Fish prices would be expected to rise by 47% and fuel price by 114%. This would result in an increase in profits of around 8% to small pelagic fisheries in the Catalan sea.

The “Global community” scenario (B1 in SRES) supposes a more integrated, ecologically friendly world with a stable population, and reduction in use of fossil fuels and material goods. Fish prices are predicted to fall by 20% (due to increased importations) and fuel price increase by 76%. This would result in a collapse in profits to around 6% of current levels for small pelagic fisheries in the Catalan sea.

Relevance for Policy:
  • Common Fisheries Policy
  • ICZM Protocol to the Barcelona Convention
  • Integrated European Maritime Policy (IMP)
  • Marine Strategy Framework Directive
  • Water Framework Directive


Lead Author:

Ben Tomlinson
Agrocampus Ouest (AGRO)
Date of research: October 2014

Related articles:

Population dynamics of sprat in the Baltic Sea 

Changes in the upper trophic level: impact on fish

Changes on stocks and management in saithe fishery 

Early life stage survival of Baltic cod

Extreme ecological events and jellyfish outbreaks

Growth model for jellyfish Pelagia noctiluca 

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This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 266445
© Vectors 2015. Coordinated by Plymouth Marine Laboratory.