IJA-2018v8n17 - page 7

International Journal of Aquaculture, 2018, Vol.8, No.17, 127-136
128
for studies in which fish are needed to be sampled and sacrificed for later laboratory analyses (e.g., dietary or
reproductive analysis) (Fernandes et al., 2017). The MS-222 chemical name is tricaine methanesulfonate. It is sold
as Tricaine-S and Finquel. It comes as a white, crystalline powder that can be dissolved in water at up to an 11%
solution and characterized by rapid sedation induction (Shawn et al., 2004).
2-Phenoxyethanol (2-PE) (1-hydroxy-2-phenoxyethane) is a moderately water-soluble, colourless, oily, aromatic
liquid often used as a topical anesthetic and commonly used in closed fish transport systems. It is suitable for
aquaculture operations because of its easy preparation, low cost, rapid induction and rapid uneventful recovery,
and has bactericidal and fungicidal properties (Tsantilas et al., 2006). Nevertheless, there are some indications that
2-Phenoxyethanol may be a probable hazard to the handler causing fatigue and drowsiness (Velisek et al., 2007).
Mugil cephalus
and
Sparus aurata
are of the foremost preferable fish species by the local Egyptian consumers.
Marine fish farming in Egypt began in 1976 with the culture of gilthead sea bream. The main source of cultured
sea bream in Egypt is the extensive and semi-intensive commercial earthen ponds, which are estimated at 8,000 ha
(Sadek, 2000). Mullets are also an important component of Egyptian fisheries and are considered as one of the
most important cash crops from artisanal fisheries in the numerous lagoons throughout the country. Mullet are
cultured in a large number of countries worldwide, usually in extensive and semi-intensive pond systems. Egypt
has a long history of mullet aquaculture, which was traditionally practiced in the “hosha” system in the Nile Delta
region for centuries (Eisawy and El-Bolok, 1975). Currently, Egypt is a leading country in mullet aquaculture
with a record production of 156,400 tonnes in 2005 (Saleh, 2008).
The objective of the current study was to examine the efficacy of different doses of clove oil, Tricaine
methanesulfonate (MS-222) and 2-Phenoxyethanol as a calming agent in order to determine the optimal dose for
short time fish handling of juveniles and adults
Mugil cephalus
and
Sparus aurata
as an example of a common
highly economic species in the Egyptian market.
1 Materials and Methods
The current study was carried out starting from October 2013 to February 2014 in El Max research station located
in Alexandria Governorate affiliated to the National Institute of Oceanography and Fisheries, Egypt. Juveniles and
adults of both
M. cephalus
and
S. aurata
were chosen as test animals based on their high economic value in the
Egyptian market.
1.1 Maintenance of test animals
Fish were maintained in circular fiberglass tanks (1000 L
3
). Water quality parameters were as follows: pH 7.55,
Do 6.25 mg/L, ammonia 0.22 mg/L, nitrite 0.07 mg/L, alkalinity 600 mg/L, water temperature 22±1°C and total
hardness 780 mg/L.
Mugil cephalus
fish average weight (mean ±SD) was 39 ±15 g for juveniles, while average
weight was 329 ±31 g for adults.
Sparus aurata
fish average weight (mean ±SD) was 52 ±12 g for juveniles,
while average weight 358 ±21 g for adults.
1.2 Experimental design and procedure
Fish had been starved for 24 hrs prior to the experiment. Three types of anesthetics clove oil, Tricaine
methanesulfonate (MS-222) and 2-Phenoxyethanol were used. Fish were exposed to (5, 10, 15 mL
-1
for juvenile)
and (15, 20, 25 mL
-1
for adults) concentration of clove oil, (50, 75, 100 mL
-1
for juvenile) and (100, 125, 150 mL
-1
for adults) concentrations of MS-222, (200, 250, 300 mL
-1
for juvenile) and (300, 350, 400 mL
-1
for adults)
concentrations of 2-Phenoxyethanol. The stock solution of clove oil was prepared according to (Ghanawi et al.,
2013) as clove oil is poorly soluble in water so it was mixed with Ethanol 96% (1 : 9) then concentrations were
prepared. MS-222 is readily soluble in water so different concentrations were easily prepared; however,
2-Phenoxyethanol was added directly into the anesthetic tank (Shaik, 1999).
The fish were exposed to anesthetics till stage 3 for full induction time and full recovery time. The induction and
recovery times were recorded using a stopwatch for each fish species as (mean ±SD). Each fish was let until it
reached S3 and kept in the same aquarium until it starts the recovery stage (Table 1). The time of induction was
1,2,3,4,5,6 8,9,10,11,12,13,14,15,16
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