product after it leaves the farm is controlled by other
authorities (provincial agencies for environment and food
safety). The LCA described in this paper therefore stopped
at the farm exit-gate and did not include processes further
downstream.
In the days following the workshop, the study team
further refined the resulting cradle-to-gate assessment so
that it focused on pond farming and excluded production in
cages, fences, and nets as these systems have become
relatively unimportant (see Fig. 1). Extensive pond production
of fresh catfish for local markets has also become of
minor importance and was therefore not considered
separately. Home-made feed was excluded because this
sub-system is difficult to quantify and less than 10% of the
farmers regularly used such feed (Lam et al. 2009). The
functional unit for this study was set at one metric ton
(1,000 kg) of fresh fish at the farm’s exit-gate (ready for
delivery).
Inventory analysis in LCA, i.e. life cycle inventory (LCI)
analysis, quantifies the cradle-to-gate inputs and outputs of
the production processes in the product system (see Fig. 2).
The study team decided to use a questionnaire to collect
primary data about grow-out farming and feed-milling and
to extract other data from the EcoInvent®2.0 database and
from related research projects managed by team members
and from the literature. The quality requirements for data
collection were set according to type and importance of the