Dear MARMAM community,
My co-authors and I are very pleased to share with you our most recent paper
published in the Ocean and Coastal Management journal. The manuscript presents
information on the competition for food between dolphins and fisheries of small
pelagic fishes in North Aegean Sea (Eastern Mediterranean Sea). The paper is
freely available online for the next 50 days (until January 19, 2021) at
https://authors.elsevier.com/c/1c9~M3RKK-nkh3. Feel free to read and share the
paper with your colleagues and peers.
Tsagarakis, K., Panigada, S., Machias, A., Giannoulaki, M., Foutsi, A.,
Pierantonio, N., & Paximadis, G. (2020). Trophic interactions in the “small
pelagic fish - dolphins - fisheries” triangle: Outputs of a modelling approach
in the North Aegean Sea (Eastern Mediterranean, Greece). Ocean & Coastal
Management 105474.
Abstract – The aim of this work is to assess potential effects on dolphins
caused by fishing Small Pelagic Fish (SPF) in the North Aegean Sea (Eastern
Mediterranean, Greece) ecosystem due to competition for food. To this end, an
existing Ecopath ecosystem model was updated with dolphins' abundance estimates
derived from a recent dedicated aerial survey. The approach included the
quantification of trophic impacts and the estimation of the fraction of
production of SPF that is consumed by dolphins and their main competitor, the
purse seine (PS) fishery. Overall, competition for resources (i.e., SPF)
between purse seines and dolphins was at relatively low levels as revealed by
the analyses of flows in the "small pelagic fish - dolphins - fisheries"
triangle, despite the relatively high abundance of dolphins in the NAS compared
to adjacent areas. Specifically, the consumption of anchovy's production by
dolphins was very low (3.6%) while consumption by the PS fleet was almost four
times higher (13.1%). A much larger fraction (71.8%) of consumption of
anchovy's production was attributed to other predators. The competition for
sardine was at slightly higher levels than for anchovy (4.6% consumption by
dolphins and 20.4% removals by the PS fleet). Even when different SPF abundance
estimates were assumed to take into account uncertainty and historical records
from acoustic surveys, food competition didn't seem to be an important issue.
Nevertheless, as anchovy (and to a lower extent sardine) was found to be a key
forage species in the North Aegean Sea ecosystem according to two food web
indices (SURF and Connectance indices) estimated, special attention should be
placed to ensure that the dolphins' populations are not threatened by food
depletion in the future.
Please feel free to email with any questions.
On behalf of all authors,
Nino
--
Research Associate
Tethys Research Institute
www.tethys.org
ORCID: https://orcid.org/0000-0002-1210-8831
Mobile: +44 (0)7581737669
Phone: +44 (0)1249813815
Skype: pierantonio_nino
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