WP 2: Sampling program and methodology for trophic studies

To understand ecosystem functionality we need a comprehensive sampling program and exploration of new observational methods. This includes increasing our knowledge about the interactions between the most important plankton, fish and benthic species, and the fluxes of biomass and energy through the food webs (WPs 3-5) and up the food chain to main predators like cod (WP 6). An important part of this is increased competence for both technicians and researchers.

IMR and PINRO have regular sampling of stomachs of cod (since 1984), capelin and polar cod (since 2005), and IMR have sporadic/short time stomach sampling of blue whiting, Greenland halibut and haddock and a few other species. PINRO includes 10-15 additional fish species in their regular monitoring. The coordinated sampling has established long and valuable time series, and diet studies giving important input to management. This work has resulted in joint procedures and databases, and substantial dissemination of results in the form of stock assessments, reports, management plan and scientific publications (see Jakobsen and Ozhigin 2011).

The activity in WP 2 will be focused on covering the most important biological processes and address specific questions in the thematic work packages. This involves optimization of the spatial and temporal coverage and mapping trophic interactions (WPs 4 and 5), building a comprehensive food web topology (WP 5), and constructing energy flow through the food webs (WP 3).

The activity involves joint field effort with PINRO, development of a training program for technicians and establishing procedures for data handling. Coordination with the joint IMR-PINRO ecosystem surveys and other relevant activities is of particular importance for this WP and for the SI overall. In addition to information on feeding and diet, WP2 will also focus on providing data on biomass and biomass conversion factors which will allow estimates and construction of budgets for flow of energy and matter in the food webs, including production and food consumption by selected species, groups and trophic levels.

The experience gained during the period of the SI will be used to improve the monitoring program for the Barents Sea ecosystem, ensuring spatial and temporal coverage of trophic interactions and necessary process studies to understand trophic dynamics in the Barents Sea. To achieve this we need to target the following:

Specific tasks:

- Define the ecologically important plankton, fish and benthos species by three criteria 1) biomass dominance (typically important commercial species), 2) sensitive species due to life history or habitat (for, example arctic species) and 3) key representatives for bio-geographic groups (Boreal, Arctic etc).

- Define the vital stages/periods/areas when/where trophic interactions are most crucial and influence the population structure and/or abundance for plankton, fish and benthos.

- Evaluation of optimal diet analyses (stomach, isotope and fatty acid) will be done for each species/group.

- Decide the needed sampling precision level for diet analyses based on the output from previous points, from high (diet analyse in lab) to low (diet analyse on board) precision.

- Define sampling extent based on the output from the previous points and evaluate it by statistical analyses