Modelling of Taste-Taint in Fish ... 45However, gills are considered to be the predominant path of uptake because of
the reported relatively low octanol-water partition coefficient (KOW) of both
these two chemicals (Howgate, 2004).
A substantial amount of research has been undertaken to characterize the
problem and/or to find an effective control mechanism. Taste-taint in fish-
flesh due to GSM and/or MIB in RAS has been reported to include, but is not
limited to, barramundi (Lates calcarifer) (Hathurusingha and Davey, 2014),
Murray cod (Maccullochella peelii peelii) (Palmeri et al., 2008), rainbow trout
(Oncorhynchus mykiss) (Robertson et al., 2006), arctic charr (Salvelinus
alpinus) (Houle et al., 2011), largemouth bass (Micropterus salmoides), and;
white sturgeon (Acipenser transmontanus) (Schrader et al., 2005). This
problem is not unique however to vertebrate fish but also to other fish species,
such as shrimp and clams (Howgate, 2004).
Even though this problem directly impacts on the marketability of the fish
there are no reported associated health affects to the fish well-being or to
human consumers (Bai et al., 2013). A number of approaches to remove (or
inactivate) these chemicals have been investigated but effective practices to
control taste-taint in farmed fish apparently have not gained acceptance
(Howgate, 2004; Schrader et al., 2010).
Purging of RAS fish post-growth in clean water and prior to marketing is
widely practised to leach taste-taint chemicals (Tucker and van der Ploeg,
1999). Tucker (2000) showed that the time taken for purging is dependent on
factors such as the environmental conditions of the grow-out ponds, the nature
of the taste-taint chemicals and farming methods employed, and; the type of
fish farmed. The drawbacks with the double handling of fish required,
intensive labour, time taken for purging, higher water demand and separate
tanks for purging have led to the search for an attractive alternative. Widrig et
al. (1996) argued that an economically feasible means is yet to be found to
purge taint causing chemicals.
Elimination of taste-taint chemicals from growth water can be useful in
manipulating taint development in fish. Hathurusingha and Davey have
recently investigated the use of low concentration of hydrogen peroxide as a
benign biocide to control GSM and MIB in RAS growth water using a special
apparatus that can read-and-dose hydrogen peroxide concentration in growth
water in real-time (Hathurusingha and Davey, 2016 a). They have reported
promising results in pilot-scale studies and concluded that induced micro-
mixing is likely to be required to deliver better results in commercial-scales
studies (Hathurusingha, 2015).