Transcript Data_Workshop29630June2009

Stakeholder worskshop
DEEPFISHMAN
Brussels
29-30 June 2009
Data availability
DEEPFISHMAN Stakeholder workshop Brussels, 29-30 June 2009
Type of Data
Problems
Fishing
Times series of fleet, catch and effort
Start time of time-series, resolution,
completeness
Biology (biological parameters, stock
structure)
Uncertainty
Biodiversity
By-catch, benthos, VMEs, fishing impact,
Often limited, observation data provide bycatch, not all fleet covered
Economy
See G. Haraldsson’s presentation
Social
See G. Haraldsson’s presentation
Assessment methodologies
Most assessment exploratory, not validated
even for redfish “data rich” stock
Management
Data on management procedure,regulation
available
Impact on fleet poorly known
DEEPFISHMAN Stakeholder workshop Brussels, 29-30 June 2009
More data allow more realistic
assessment and management
Example 1:
Tally book data provide haul by haul catch and effort
The view of the fishery is different for that for EU logbook
data (hauls aggregated per day and statistical rectangle)
Tally books allow : - better estimates of CPUEs
- account of fishing strategies on
trends in landings and CPUEs
DEEPFISHMAN Stakeholder workshop Brussels, 29-30 June 2009
Example 2.
-the effect on fishing on both exploited species
and other species in the ecosystem is primarily
a matter of mortality
- for benthos mortality can be assessed from
the frequency of trawling
DEEPFISHMAN Stakeholder workshop Brussels, 29-30 June 2009
Example 2.
-the effect on fishing on both exploited speices and
other species in the ecosystem is primarily a matter
of mortality
- for benthos mortality can be assessed from the
fequency of trawling
From Piet and Quirijns (2009). The importance of scale for fishing impact estimations. can. J. Fish. Aquat. Sci.
When data resolution increases a large proportion of the seabed appears
no to be fished:
% of unfished bottom (% unimpacted benthos) estimated lower from VMS
No
change inStakeholder
estimated
fishing
mortality
for target species
DEEPFISHMAN
workshop
Brussels,
29-30 June 2009
Questions
Which data can be made available for stock and ecosystem
assessment
- VMS data:
which are available?
what can de done with?
- Tally book data: main use might be stock assessment?
- Data availability in the future (e.g. electronic logbook)
DEEPFISHMAN Stakeholder workshop Brussels, 29-30 June 2009