Stock and
ecosystem assessments rely heavily on abundance indices and other data products
from surveys using a variety of observation methods, including egg sampling,
trawling, acoustics, and video. In Europe and elsewhere an extensive
coordinated survey programme has been put into place to collect these data. Recently
assessment methods have been evolving rapidly, leading to the need for a wider
range of information, as well as new methods for data use.
For a number
of stocks the weight given to survey indices in the assessment model is rather
low compared to commercial landings, which raises questions of potential
mismatch between models and survey coverage or designs, lack of understanding
of survey catchability and its variability, or issues with other data inputs.
Thus, new approaches may be required for treating survey data, or even how the
surveys are run (design, parameters) to improve their usefulness in assessments.
Another major
challenge and emerging field for surveys is obtaining abundance indices for
species that require multiple surveys or survey methods to cover the full
extent of their distribution. This happens when stocks are distributed across
multiple countries and surveyed by multiple national surveys, stocks are found
across multiple habitats and require habitat specific survey methods, vertical
distribution requires sampling with trawls and acoustics, different life stages
require different methods, and survey methodologies such as gears, vessels or
sampling designs change through time. These cases likely encompass most commercial
species.
Ecosystem
assessments have their own set of requirements for survey derived data
products. As this field develops, the need for standardized survey data
treatment methods, defining best practice guidelines and more fundamentally
evaluating whether survey products are fit for purpose arises.
To review
issues and explore solutions for improving the usefulness of survey products,
papers are welcome on the following topics based on empirical data or
simulation studies:
- Evaluation of the performance of survey products for current stock and ecosystem assessment methods and potential improvements
- Survey designs for improved survey products (precision, cost efficiency)
- New models for including survey products in stock and ecosystem assessments
- Impact of survey and sampling designs on abundance indices, biological parameters and ultimately stock and/or ecosystem assessment results
