Applied Ecophysiology: An Integrative Form to Know How Culture Environment Modulates the Performance of Aquatic Species from an Energetic Point of View - Aquaculture and the Environment: A Shared Destiny - page 163

This chapter will dedicated to show some examples that illustrate how applied
ecophysiology have been solving some questions related with culture organisms and its
consequences on production. In this chapter an integrative perspective related with immune
condition is included taking into account that many of healthy problems observed on
cultured animals are derived from immune problems provoked by inappropriate culture
environments. Finally, some aspects related with experimental designs that must be
considered in studying of applied ecophysiology are proposed. To exemplify, two species
groups were formed: molluscs and crustaceans. Into the mollusks, examples with bivalves,
gastropods and cephalopods are presented. Into the crustacean, examples with crabs and
shrimp are used to illustrate how applied ecophysiology can improve aquaculture. In the
case of fish a new encyclopaedia of fish physiology (from genome to environment) was
published recently (Farrell, 2011). For that reason fish were not included in this chapter.
3. Molluscs ecophysiology
3.1 The case of bivalve Argopecten purpuratus
Bivalve filter feeders are capable of ingesting living and inert particles suspended in the
water column that are responsible for the energetic input. In some species was
demonstrated that detritus may contribute to the diet during periods in which the
environmental offering of phytoplankton is unable to satisfy their energetic requirements.
Although organic materials from discarded feed and faeces from salmon culture contributes
to the diet of pectinids maintained in culture in southern Chile, phytoplankton is the main
nutrient source for bivalves aquaculture (Farias & Uriarte, 2006). As pointed out, the shell
growth and biochemical composition of larvae give clear indications about changes in the
quality of the environment that are basic to determine how water nutrients and
phytoplankton modulates the biomass production of bivalves (Ferreiro et al . , 1990).
Studying pectinid A. purpuratus several ecophysiological parameters were investigated to
find the best conditions to cultivate this bivalve species. In a first step biochemical
composition of larvae and spat was used to evaluate the energy metabolism and the
nutritional condition of hatchery reared bivalves (Farías et al . , 1998). Adults from
commercial long lines were stimulated to spawn using temperature shock and total lipids,
soluble protein and total carbohydrates of eggs, larvae and spat were evaluated.
From that result was evident that lipids were the main source of energy while protein is
deposited into the biomass. At the same time, an increment on carbohydrates was observed
suggesting that the metabolic pathways related with transformation of lipids into glucose
could be activated during larvae development and putting in evidence that quality of food
used during larvae culture greatly influenced the storing of reserves and the survival of the
resulting spat (Fig. 1).
These results were confirmed latter when the effect of dietary protein content on
biochemical composition of postlarvae, spat and gonadal development of A . purpuratus was
tested (Uriarte & Farías, 1999; Farías & Uriarte, 2001). From that results it was evident that
pectinid, and other bivalves production depends on the quality of the diet and the
environment in which they inhabit (Fig. 2). Results on reproductive conditioning of adults
showed that feed quality affect the quality of eggs depending of the species, so for
A. purpuratus an increase in micro algal protein produce an increase in fertility and growth rate