Bañón, R., Maño, T., and Mucientes, G. 2016. Observations of newborn blue sharks Prionace glauca in shallow inshore waters of the north‐east Atlantic Ocean. Journal of Fish Biology,
Mejuto, J., García-Cortés, B., Ramos-Cartelle, A., and Abuin, E. 2014. Note on the observation of recruits of blue shark, Prionace glauca,in near coastal areas of Galicia (NW Spain)
during the summer of 2013. Collect. Vol. Sci. Pap. ICCAT, 70: 2452-2461.
@gmucientes @Fanequeiro @ecologiaazul @FisheriesIIM#coastalsharks #sharkscience #Galicia
OF BLUE SHARKS IN
COASTAL WATERS OF
Blue shark, Prionace glauca (L.1758), is an oceanic
epipelagic and fringe littoral species with a worldwide
distribution in temperate and tropical oceans. It is one of
the most abundant, fecund and fastest growing sharks.
The Blue shark is also one of the most exploited shark
species in global and European waters.
What is the reason behind the anomalous occurrence of
juvenile blue sharks in Galician coastal waters, NW Spain,
during the last summers?
With the aim of elucidating the main factors explaining the
anomalous presence of juveniles of P. glauca in coastal
waters off Galicia, we launched a monitoring program of
new records following a citizen science approach.
Reported data included date, position, size or sex.
Photographs and/or videos are usually provided to confirm
During 2016 and 2017 a total of 65 observations, totalizing 106 individuals, were
reported and data uploaded to apublic online platforms via shiny app.
Most records were registered during summer months (specially July), confirming
previous results (Bañón et al.2016).
Mean size of individuals was 70±26 cm total length.
The anomalous presence of numerous blue shark neonates and juveniles in
shallow inshore waters off Galicia was first observed in summer 2013 (Mejuto et al.
2014). This unusual phenomenon has been posteriorly confirmed with multiple
observations during 2014 and 2015 (Bañón et al. 2016) and this monitoring
program also confirm this phenomenon during 2016-2017.
Changes in oceanographic conditions, high recruitment events or changes in the
nursery area are the most probable causes of this unusual behavior. However, to
reach solid conclusions an exhaustive follow-up of new observations are needed.
Figure 3. Distribution of Blue shark records 2016-2017. Scan qR code to see the shiny app.
La presencia anómala de juveniles de tiburón azul,
Prionace glauca (L.1758), en aguas costeras poco
profundas de Galicia se observó por primera vez en el
verano de 2013. Este fenómeno inusual ha sido confirmado
posteriormente en los veranos de 2014 y 2015. El presente
trabajo amplía los registros de P. glauca en Galicia durante
el periodo 2016-2017 en 106 individuos.
R. Bañón, A. Maño,
D. Villegas-Ríos and
Figure 2. Blue sharks in Galicia (Picture: Toño Maño, 2015). Scan qR code to see youtube video.
Figure 1. Frequency of blue shark records during 2016-2017
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