It is an important finding that fish considered to be a typical marine stenohaline organism could maintain ion and water balance as low as the isosmotic point, and exhibit survival and positive growth rates in salinities as dilute as 6 ‰. Segmental linear regression analyses revealed that the calculated isosmotic point for wolf eel of ~ 10.6 ‰ was a critical limit for maintaining growth performance and osmoregulatory homeostasis. Muscle water content increased with increasing salinity dilution (77.9% water in 30 ‰ 79.8% water in 6 ‰), and plasma osmolality (~ 320 mOsm kg −1) was maintained in salinities as dilute as 9 ‰ but was significantly lower (~ 280 mOsm kg −1) in the most dilute salinity of 6 ‰. Specific growth rate was maintained above 3.0% mass day −1 at salinities of 30 and 14 ‰, but was significantly reduced at 9 (2.9% mass day −1) and 6 ‰ (2.0% mass day −1).
Growth rate remained positive in all salinities throughout the 8-week trial. At the conclusion of the growth study, fish were sampled for analysis of gill and intestine enzyme activity, plasma ion content, and muscle moisture.
#Juvenile wolf eel series
This study examined growth performance and osmoregulation in juvenile wolf eel ( Anarrhichthys ocellatus) held in a series of dilute salinities (30, 14, 9, and 6 ‰) over an 8-week trial.
Members of wolf fish family Anarhichadidae have emerged as potential cold-water marine aquaculture species.
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