A
new model developed by scientists of the European Commission's Joint
Research Centre (JRC) allows the potential presence of bluefin tuna
to be tracked through daily updated maps, helping to protect
endangered stocks and fight illegal fishing. The model, based on
satellite remote sensing data, provides for the first time an overall
view of the preferred bluefin tuna habitats in the Mediterranean Sea,
as well as their changes over time. Satellite-based habitat mapping
can help identify more precisely areas to be inspected or to be
closed for fisheries and it can also help refine estimates of fish
stocks, thus contributing to a more effective fisheries management.
Máire
Geoghegan-Quinn
European
Commissioner
for Research and Innovation
 "This
model will help to ensure sustainable management of bluefin tuna,
actively contributing to two of the most pressing challenges for the
future: food security and protection of the environment. Another good
example of how science and research provide support to European Union
policies." |
European
Commissioner for Maritime Affairs and Fisheries, Maria Damanaki,
said"Responsible fisheries management decisions that ensure the
sustainable exploitation of fisheries resources and the availability
of fish for future generations worldwide rely on good science. New
findings, like the JRC's new model, will help us greatly in our
efforts to protect bluefin tuna and fight illegal fishing practices."
The
JRC habitat model allows the creation of near real-time maps of
feeding and spawning potential bluefin habitats in the Mediterranean
Sea, as well as habitat maps over a decade. The novelty of this model
is the use of satellite data on the concentration of chlorophyll on
the sea surface, as well as temperature, to track specific
oceanographic features, which play a key role on the fish
distribution.
The
results achieved through the model clearly highlighted that bluefin
tuna feeding and spawning is concentrated in some recurrent
locations. Areas most frequently chosen for nutrition are on the
northern side of the Mediterranean. Reproduction starts in May in the
eastern part of the Mediterranean and ends in July in the western
part.
However,
the results also displayed a strong seasonality in habitat size and
locations, as well as high year-to-year variations for the potential
spawning habitat depending on regional weather conditions. This
variability is key to evaluating the pertinence of Marine Protected
Areas (or sensitive areas) for this species.
Bluefin
tuna is a commercial fish of high market value which has been
strongly overexploited for 15 years, especially in the Mediterranean
Sea. The largest stock of adults which reproduce in the Mediterranean
Sea is now at its lowest on record, around 40% of late 1950s' level.
In
the past years the International Commission for the Conservation of
Atlantic Tunas (ICCAT) has set lower quotas, established a restricted
fishing period and recommended measures to enforce fisheries control.
However, there is a need to increase the knowledge about spawning
grounds for exploring additional management measures.
The
implementation of a habitat-guided management could help identify
spawning areas to be partially closed to fishing, thus protecting the
spawners and ensuring adequate repopulation. Moreover, by restricting
authorised fishing areas, control operations can be better targeted
to fight illegal fishing, which is estimated to account for more than
one-third of total catches in recent years.
The
JRC habitat model can be adapted to other species of commercial
interest. Potential habitat maps of fish at basin scale could help to
produce more reliable assessments of fish stocks and can contribute
to the planning of more efficient and sustainable use of limited
maritime space.
Source:
European
Commission, Joint Research Centre (JRC).
Journal
Reference:
JN
Druon, JM Fromentin, F Aulanier, J Heikkonen. Potential feeding and
spawning habitats of Atlantic bluefin tuna in the Mediterranean Sea.
Marine Ecology Progress Series, 2011; 439: 223 DOI: 10.3354/meps09321
SATELLITE DATA CAN HELP PROTECT BLUEFIN TUNA - WATERWAY NEWS - 04 DECEMBER 2011
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![Alex Villanueva Mechanical Engineer Virginiatech “Robojelly looks very similar to an actual jellyfish. Its geometry is copied almost exactly from a moon jellyfish [Aurelia aurita]. The robot is built out of silicone and uses shape memory alloy (SMA) actuators to swim. These results clearly demonstrate that the flap plays an important role in the propulsion mechanism of Robojelly and provides an anatomical understanding of natural jellyfish."](../../WATERWAYS%20PEOPLE/021211%20Alex%20Villanueva.jpg "Alex Villanueva Mechanical Engineer Virginiatech “Robojelly looks very similar to an actual jellyfish. Its geometry is copied almost exactly from a moon jellyfish [Aurelia aurita]. The robot is built out of silicone and uses shape memory alloy (SMA) actuators to swim. These results clearly demonstrate that the flap plays an important role in the propulsion mechanism of Robojelly and provides an anatomical understanding of natural jellyfish.\"")
