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#FridayScience 1

Tous on Fridays, we popularize one or more studies on microplastics in the Mediterranean.

Comparison of the bioaccumulation of microplastics by two major filter-feeding organisms: the fin whale and the basking shark


The basking shark ( Cetorhinus maximus ) ingests  more micro-plastics per day than the fin whale ( Balaenoptera physalus ) ?


Although it may seem incredible due to the size difference, the shark ingests 3.6 times more water (which contains micro-plastic) than the whale. However, the whale accumulates more plastic in its organism. Indeed, the whale ingests large quantities of small crustaceans containing high concentrations of plastic additives, while the shark is less efficient at retaining both nutrients and contaminants.


Physiological comparison between these 2 organisms:

Dessin de rorqual communde méditerraneé

fin whale

20m long


Filtration 5893 m3/day

Plankton ingested 913 kg/day

Desin de requin pèlerin

basking shark

7m long


Filtration 21,144 m3/day

Plankton ingested 31 kg/day

Amount of micro-plastics absorbed per day:

Graphique de comparaison de l'ingeston de micoplastique entre une baleine (rorqual commun) et un requin (requin pèlerin)

However, we find more tracers of micro-plastics in the whale than in the shark... 

Graphes de comparaison de l'absorption de phtalates et d'organochlorines entre une baleine et un requin

Therefore, the bioaccumulation is greater in the whale even if it ingests less micro-plastic.



The two organisms do not have the same capacity to retain the particles they filter.  Thus, the filtration system of the basking shark is much less efficient than that of the whale.

In addition, the fin whale targets krill-rich areas while the basking shark swims with its mouth open continuously. Thus, the fin whale ingests much larger quantities of krill  (913 kg/day) with non-negligible concentrations of plastic additives. 

Bibliography :  

[1] Fossi, MC, et al., Large filter feeding marine organisms as indicators of microplastic in the pelagic environment: The case studies of the Mediterranean basking shark (Cetorhinus maximus) and fin whale (Balaenoptera physalus), Marine Environmental Research (2014 )

Synthesis: Aitor Fernandez, Benjamin Pannetier 

GUI:  Benjamin Pannetier


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