42 
Fishery Bulletin 1 13(1) 
5700E 
Figure 2 
Map of the study area, showing the movement of 11 tagged and 
released banana prawns ( Fenneropenaeus merguiensis) in 2010 
between the release site (•) and recapture sites ( X ) in coastal 
waters of Hormozgan Province, Iran, in the Strait of Hormuz, 
the opening that connects the Persian Gulf and the Arabian Sea. 
vate hatchery center. A florescent elastomeric 
liquid injection was used to mark 50,000 juve- 
nile banana prawns weighing 1 g each. Injec- 
tions were made just beneath the skin tissue 
along a straight path several millimeters long 
with a 1-cc insulin syringe and a 25-gauge 
needle (Neal, 1969). Marked prawns were held 
in fiberglass tanks for 48 hours to observe in- 
dividuals that may have been injured during 
marking. Marked prawns were transported by 
small boats to the sea in fiberglass tanks. The 
release area was close to the hatchery (about 
20 min in travel time by boat). The use of these 
tanks kept fluctuations in water temperatures 
from the farm to the release area low, so that 
the temperatures measured in both areas were 
similar. Prawns were released through the use 
of a pumping system. 
The mortality rate that resulted from 
marking and handling of prawn was less 
than 3%. Dead and moribund prawns were 
removed before tagged prawns were released 
to the sea. To prohibit transfer of disease to 
wild prawn, some specimens of the juvenile 
cultured shrimps were randomly subsampled 
to test for the presence of white spot syn- 
drome disease, and prawns were released 
when no disease was found. Before the re- 
lease of prawns, the study area was investi- 
gated by gill net for shrimp predators; fur- 
ther, releases were made at night to reduce 
the threat of bird predation. Juvenile prawns 
were released in mangrove areas, which are 
nursery grounds of the banana prawn (Staples, 1985; 
Meager, 2003), in June and July 2010. 
Education and outreach efforts to raise public 
awareness of the release and recapture of prawns for 
this study included descriptive posters distributed to 
local persons. In addition, announcements were made 
in magazines and on national television broadcasts 
before, and during, the fishing season. A monetary re- 
ward program was established that paid the equiva- 
lent of USD 10 for the return of each marked prawn. 
This reward was twice as large as the reward offered 
in a successful study of tagged and recaptured sailfish 
(Hoolihan, 2003) that was conducted in the region dur- 
ing 2003-2004. 
Costs were estimated for hatchery operation, grow- 
out, and release on the basis of data from private- 
sector hatcheries. The hatchery component comprised 
the brood stock and the hatched larvae. We estimated 
mean actual costs using the detailed prawn hatchery 
model, with options for the use of either wild or domes- 
ticated brood stock, developed by Preston et al. (1999). 
The total cost (Q/i) of operations from hatchery produc- 
tion to the point when prawn larvae were 15 days old 
was calculated with the following equation: 
( 1 ) 
where q = cost per larvae for growth from nauplii to 
15-day-old postlarvae (PL15); 
Q = the number of larvae produced; and 
(p = a parameter describing the economy of scale 
(i.e., when the scale of production in- 
creases, the unit cost of production will 
decrease). For the present study, (p was 
calculated at USD 0.0024 per PL15. 
The total production (Tp) cost of grow-out of juve- 
niles from PL15 to a weight of 1 g, including prawn 
feed, employee salaries, and pumping as a part of 
the operating cost, was calculated using Hannesson’s 
(1993) formula, with some modifications: 
Tp = ( Cp ) + (Be - Bi) yt, (2) 
where Cp is the cost of pumping per square meter of 
raceway in the week, Bi and Be are the initial and end 
total biomasses of prawns, y is the cost of feed per ki- 
logram, and x is the conversion ratio of food to growth 
in biomass. In the present study, 6.5 million PL15 were 
produced and 4.7 million juveniles ranging in average 
weight from 0.98 to 1.2 g were released into the study 
area. This weight of approximately 1 g was used for 
released prawns to reduce mortality. For the purpose 
Qh = qQ'P, 
