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
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