Biology and population dynamics of rainbow prawn, Parapenaeopsis sculptilis (Heller, 1862), in coastal waters of Terong, Perak, Malaysia
Taxonomy, morphometry, food and feeding habits, reproduction and population parameters of Parapenaeopsis sculptilis Heller 1862 in the coastal waters of Terong, Perak, Peninsular Malaysia were studied between February 2012 and January 2013. A total of 120 specimens of P. sculptilis were used f...
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| Format: | Thesis |
| Language: | English |
| Published: |
2015
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/71267/1/IB%202015%2035%20IR.pdf http://psasir.upm.edu.my/id/eprint/71267/ |
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| Summary: | Taxonomy, morphometry, food and feeding habits, reproduction and population
parameters of Parapenaeopsis sculptilis Heller 1862 in the coastal waters of Terong,
Perak, Peninsular Malaysia were studied between February 2012 and January 2013. A
total of 120 specimens of P. sculptilis were used for morphometric studies and they
were collected from four different locations viz. Perak, Penang, Port Dickson and
Malacca. The morphometric characteristics investigated include the total length,
standard length, carapace length, carapace height, rostral length, second pleon segment
height, sixth pleon segment length, telson length, telson width, eye wide and eye
length. The morphometric study is aimed to investigate on the possibility of differences
in body morphometric characteristics amongst the different P. sculptilis populations in
Peninsular Malaysia waters.The result showed that all morphometric characters of
P. sculptilis from four different areas in the west coast of Peninsular Malaysia were
significantly (P < 0.05) different at 5% level except for CL, CH, RL and TEW (P >
0.50) not significant at 5% level. Feeding process particularly feeding items is one of
the important biological characteristics for species that has aquaculture potential. The
observation of the stomach contents of 360 specimens from coastal waters of Terong
Perak, found only 10.14% of empty stomachs of the P. sculptilis while 89.84% of the
stomachs filled up with foods. The highest percentages of full stomachs, 3/4 full, 1/2
full and 1/4 full were found in January, June, May and March respectively. The diet
compositions of P. sculptilis were grouped into nine different categories viz.
phytoplankton, zooplankton, mollusca, fish scales, polychaetes, appendages of
crustacean, detritus, sand and unidentified items. According to the Index of Relative
Importance (%IRI), the main food items of P. sculptilis graded as first rank was
molluscs (64.73%), and this was followed by appendages of crustacean (17.88%),
zooplankton (7.49%), detritus (2.64%), sand (2.27 %), phytoplankton (2.20%), fish
scales (1.84 %), unidentified items (1.19 %) and polychaetes (0.69%). The various composition of food items proved that the P. sculptilis is an omnivorous bottom feeder.
A study was also included to examine the sex ratio in the population of Terong coastal
waters and the annual results for the ratio was found to be 1:3.4 (Males: Females).
Consecutively, a study on the reproductive biology was carried out on 50 female
individuals each month. Samples were examined monthly and the peak Gonadosomatic
Index (GSI) of female P. sculptilis was very apparent during the months of April,
August and October in the study area. The first sexual maturity of female was attained
at a total length of 9.30 cm. The highest GSI value (5.89) was observed in April, where
the females were a mature stage. The lowest GSI (0.63) was obtained in November,
where the females were at an early active and immature phase. Relative condition
factor (Kn) values ranged from 0.99 to 1.064 (1.013±0.005, mean ±SD). Kn values
changes in various months: the highest peak was in March-April indicating the
spawning period and small peaks indicated the cycle of gonadal development. A total
of 3110 specimens of prawn were used for the works on the population dynamics of P.
sculptilis. The estimated mean total lengths for males and females were 9.13(±0.83)
and 11.96 (±2.2) cm. Length-weight relationship (LWR) parameters of both sexes was
estimated at W = 0.00027TL2.80. The estimated relative growth coefficient (b) was 2.80
for the both sexes which indicated that growth pattern of P. sculptilis was negative
allometric in the investigated area. Monthly length–frequency data were analysed by
using FiSAT (FAO ICLARM Stock Assessment Tools) software. The von Bertalanffy
growth (VBGF) parameters were estimated as asymptotic length (L) = 17.69 cm and
growth coefficirent (K) = 2 yr-1. The total mortality (Z), natural mortality (M) and
fishing mortality (F) were found to be 6.71, 1.77 and 4.94 yr-1 respectively. The
exploitation (E) rate was calculated as E = 0.74 which is higher than optimum level of
exploitation (E= 0.50). It is revealed that the status of the stock of P. sculptilis is over
exploited the in the coastal waters of Terong, Perak, Peninsular Malaysia. |
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