Thinlip Grey Mullet | European Tracking Network

Thinlip Grey Mullet

Chelon ramada

 

©Esmeralda Pereira

 

Species description and statusThe thinlip grey mullet Chelon ramada (Risso 1827) is a catadromous species distributed along the Northeast Atlantic, from the Norwegian coastline to Mauritania, on the African coast, and it includes the British Isles, North Sea, Barents Sea, Bay of Biscay, Mediterranean Sea, and the offshore islands of the Canaries (Fig.1)1. This species is frequently observed in large shoals throughout coastal areas, brackish water and entering also freshwater2,3,4,5. According to the IUCN red list of threatened species is classified as least concern6. The wide distribution and success of this species is attributed to their high euryhaline capacity, feeding plasticity (detritivorous) and trophic position, that allows them to occupy diverse environments and explore extensive feeding areas5,7.

Among the mugilidae family, is known to perform the furthest upstream trophic migration into freshwater feeding grounds8 and during their life cycle, display a complexity of habitat use and movement patterns. Adults migrate to offshore spawning areas were eggs are fertilized and larvae use selective tidal stream transport to aid migration within and through estuaries to reach nursery areas9.  Juveniles are to some extent euryhalines and capable of joining adult movements. Adults can either stay in the estuarine zone, where movements and feeding rhythm follows the flood - ebb tide, with a minimum effort2, or migrate further upstream reaching freshwater habitats located as far as 350 km upstream of tidal influence8. Thus, beyond their growing contribution to fisheries economy of many Mediterranean countries10, C. ramada play an important ecological role in trophic webs by promoting fluxes of energy and organic matter along the aquatic system (biological vector)2.

Figure 1: Distribution of the thin-lipped grey mullet in the North-East Atlantic Ocean, Mediterranean and Black Sea ( From: Freyhof and Kottelat, 2018).

Knowledge gaps:

  • Population trend remain unknown and monitoring programs are absent. Species-specific stock assessment and time-series data do not exist11;
  • Deeper comprehension of migration patterns, individual behavioral profiles and their implication at the population level;
  • Understand the drivers supporting the migrations to freshwater habitats and along the marine environment.
  • Impact of river fragmentation by dams, intensification of fishing effort and climate change.

 

Region of interest: Central to Western Europe, including the Mediterranean region.

Telemetry tools: The studies conducted with biotelemetry targeting the thin-lipped grey mullet are relatively scarce. Acoustic and transponder tags (associated to PIT antennas installed in fishways) are being applied to study the migratory patterns covering both freshwater and marine habitats. Radio telemetry can be an option if the objective of the study is to focus on the freshwater movements. Data storage tags can complement the acoustic telemetry to evaluate the habitat (depth) use at sea.

Benefits: By enlarging the coverage of the acoustic receiver arrays with the ETN it will be possible to infer the migratory plasticity of the species along the latitudinal gradient of distribution. On the long term, data gather with the ETN network can be used as a starting point to answer large scale questions under the scope of climate change. Namely, identify possible distribution shifts, the main drivers, the migratory strategies and define possible management actions.  

Contacts: Esmeralda Pereira (ecpereira@fc.ul.pt); Bernardo Quintella (bsquintella@fc.ul.pt) and Pedro Raposo de Almeida (pmra@uevora.pt).

References:

1Turan, C. 2015. Biogeography and distribution of Mugilidae in the Mediterranean and the Black Sea, and North-East Atlantic. In Biology, Ecology and Culture of Grey Mullet (Mugilidae), pp. 116–127. Ed. by D. Crosetti, and S. Blaber. CRC Press, Taylor & Francis Group, Florida. 529 pp.

2 Almeida, P.R. (1996). Estuarine movement patterns of adult thin-lipped grey mullet, Liza ramada (Risso) (Pisces: Mugilidae), observed by ultrasonic tracking. Journal of Experimental Marine Biology and Ecology 202: 137–150.

3Laffaille, P., E. Feunteun and J.-C. Lefeuvre. 2000. Composition of fish communities in a European macrotidal salt marsh (the Mont Saint-Michel Bay, France). Estuarine, Coastal and Shelf Science 51: 429–438

4 França, S., Costa, M. J, and Cabral, H. N. 2011. Inter- and intra-estuarine fish assemblage variability patterns along the Portuguese coast. Estuarine, Coastal and Shelf Science 91: 262–271.

5 Whitfield, A.K., Elliott, M., Basset, A., Blaber, S.J.M and West, R.J. 2012. Paradigms in estuarine ecology–a review of the Remane diagram with a suggested revised model for estuaries. Estuar. Cost. Shelf Sci. 97: 78–90.

6 Freyhof, J. and Kottelat, M. 2018. Chelon ramada (amended version of 2008 assessment). The IUCN Red List of Threatened Species 2018: e.T135714A136554014. https://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T135714A136554014.en. Downloaded on 13 February 2020.

7  Cardona, L. (2016). Food and Feeding of Mugilidae. In: Crosett, D. and S. Blaber, S. (eds.). Biology, Ecology and Culture of Grey Mullet (Mugilidae). CRC Press, Boca Raton, USA.

8 Sauriau, P-G., Robin, J-P., and Marchand, J. 1994. Effects of the excessive organic enrichment of the Loire Estuary on the downstream migratory patterns of the amphihaline grey mullet (Liza ramada) (Pisces: Mugilidae). In Changes in Fluxes in Estuaries: Implications from Science to Management, pp. 349–356. Ed. by K. R. Dyer, and R. J. Orth. Olsen & Olsen, Fredensborg, Denmark. 485 pp

9 Trancart, T., Lambert, P., Rochard, E., Daverat, F., Coustillas, J., and Roqueplo, C. 2012.Alternative flood tide transport tactics in catadromous species: Anguilla anguilla, Liza ramada and Platichthys flesus. Estuarine, Coastal and Shelf Science, 99: 191–198.https://doi.org/10.1016/j.ecss.2011.12.032

10 Crosetti, D. 2015. Current state of grey mullet fishery  and culture. In Biology, Ecology and Culture of Grey Mullet (Mugilidae), pp. 398–450. Ed. by D. Crosetti, and S. Blaber. CRC Press, Taylor & Francis Group, Florida. 529 pp.

11 Wilson, K., and Veneranta, L. (Eds). 2019. Data-limited diadromous species – review of European status. ICES Cooperative Research Report No. 348. 273 pp.