Pakistan J. Zool., vol. 42(2), pp. 169-176, 2010.
Reproductive Biology of Sailfin Molly, Poecilia latipinna (Lesueur,
1821) in Wadi Haneefah Stream, Riyadh, Saudi Arabia
Ali S. Al-Akel*, Fahad Al-Misned, Hmoud F. Al-Kahem-Al-Balawi, Khalid A. Al-Ghanim, Zubair
Ahmad and H. Annazri
Zoology Department, Science college, King Saudi University, P. O. Box 2455, Riyadh, 11451, Kingdom of
Saudi Arabia
Abstract.- The reproductive biology of Poecilia latipinna inhabiting Wadi Haneefah stream, Riyadh, Saudi
Arabia was studied. The fish (P. latipinna) were found reproductively active round the year. The highest reproductive
activity occurred from February to May and August to November which defined two distinct annual periods of
reproduction. There was a monthly variation in sex ratio. More females than males were registered during the whole
period of study. Males mature at the total body length of 51 mm, while the female maturity was attained at 48 mm.
Fifty percent male and female population achieved maturity at the length of 67 mm and 65 mm body length,
respectively. The absolute fecundity of P. latipinna ranged from 35 to 161 eggs, the value of co-relation coefficient (r)
indicates that the fish's fecundity has stronger relation with weight than with the length.
Key words: Poecilia latipinna, reproductive biology, maturity, sex ratio, fecundity
INTRODUCTION
Reproduction is the process which occurs
for the continuity of the gender. It differs according
to fish type and environment; cold water fish
reproduce once a year and have a short reproductive
season, while warm water fish (tropical and subtropical) usually have a longer reproductive season
which may extend from 7 to 9 months every year
(Qasim, 1973). Reproduction of bony fish has
attracted many researchers around the world
(Ruzyeki, 1998; Pusey et al., 2001; Aday et al.,
2002; Heibo and Vollestad, 2002; Machado et al.,
2002; Privitera, 2002; Arlinghaus and Wolter, 2003;
Orlando et al., 2007; Dominguez-Petit et al., 2008).
Poecilia latipinna is an ornamental fish,
originally occurring in North- Eastern area of USA
and South America. It is widely distributed around
the world and is a protein source (food) in some
countries (Al-Ghanim, 2005) inspite of its small
size. Besides that it serves as biological control for
insects. P. latipinna was first record in Saudi Arabia
in 1983 in Ank, the Eastern Sector (Ross, 1985), and
*
Corresponding author: zahmed@ksu.edu.sa or
halkaham@ksu.edu.sa)
0030-9923/2010/0002-0169 $ 8.00/0
Copyright 2010 Zoological Society of Pakistan
in Wadi Haneefah stream, Riyadh (central sector) by
Siddiqui and Al-Harbi (1995).
Many previous studies carried out on P.
latipinna (an exotic species) in Wadi Haneefah
stream have focused on its genetic nature and some
biological aspects like feeding, age and growth
besides the effects of salinity and temperature on
behaviors of this species (Abrahams, 1988). The
reproductive biology of this species, introduced in
this environment, has not yet been studied. The
present work aims at studing the reproduction of P.
latipinna which includes sex ratio, monthly
variations in gonado-somatic index , variations in
the maturity stages and the relation between
fecundity and total body weight and total length of
the fish.
MATERIALS AND METHODS
Fish sampling and biological data:
Monthly samples of P. latipinna were collected
from Wadi Haneefah stream by cast net. A total of
360 specimens of P. latipnna were collected over a
period of 15 months. Morphometric characteristics
viz., wet weight and total length of each fish were
recorded. All specimens were dissected, sexed and
their gonads were removed and weighed to the
nearest mg. Stage of maturity of each individual fish
was determined and classified into following five
170
A.S. AL-AKEL ET AL.
stages depending on its morphological conditions
(Pusey et al., 2001).
Stage I (Resting or Immature): Gonads look
gray in color, small in size and stripe shape.
Stage II (Early developing-stage): Ovary is
pale or orange in color with few eggs. The testis
extends inside a white casing.
Stage III (Developing-stage): Ovary is orange
in color with red spots; eggs are dark, can be seen
by naked eyes and there were also droplets in the
eggs. Testis is of white gray color.
Stage IV (Late developing-stage): Ovary is of
orange color and eggs are clearly visible. There are
oily spots in a larger scale of the egg. Testes are of
dark color between gray and white, no sperms are
seen.
Stage V (Gravid-stage): Color of ovaries
tends to appear between yellow and orange and eggs
are round and full of yolk, form small single drop.
The testes are transparent and white; sperms are
ejected by pressing the aperture genitals.
Gonado-somatic index
The monthly gonado-somatic index (GSI) was
calculated from the following formula:
These indices were expressed as the monthly
averages and plotted against months.
Sex ratio (SR)
The sex ratio was calculated from the formula
given below:
Length at first maturation and 50% maturation
The length of smallest matured fish is
considered as length at first maturity. To estimate
the size at 50% maturity (the size at which 50%
fishes got matured) the fishes were grouped in 1mm
group. The percentage of mature fishes were plotted
against their corresponding lengths. The Lt 50, the
length at which 50% fishes were mature, was then
calculated as described by Caputo et al. (2003).
Fecundity
Fecundity was estimated by counting all the
eggs found in the female ovary during the spawning
season. Fish ovary was taken and put in small petri
dish and the ova were separated from the ovarian
tissue with the aid of dissecting needle, and all ripe
ova were counted under the binocular microscope.
Fish length and total weight were recorded
separately for individual fish and plotted graphically
against fecundity. The relationship between these
variables and fecundity were estimated according to
the following formula: F= aXb, Where F is
fecundity, X is body weight in g or body length in
mm, ‘a’ is intercept and ‘b’ is slope (Lagler, 1978).
This equation became linear when transformed in
logarithm as follows: Log F = log a + b log X.
RESULTS
Monthly variation in sexual maturity stages
Data of monthly changes in the stages of
sexual maturity is presented in Table I. It has been
observed that part of P. latipinna population in
Wadi Haneefah stream is reproductively active
round the year. The highest reproductive activities
seem to be occurring from February to May and
August to November defining two distinct annual
period of reproduction coinciding with the period of
reduced water current and high availability of food
(Lower water level and high planktonic population
was reported by Al-Ghanim, 2005 in these months
period). An irregular pattern of distribution of
different maturity stages (I-V) was observed
(Table I).
Variations in gonado-somatic index (GSI)
The monthly changes in GSI are presented in
Figure 1. Male GSI remained lower as compared
with females. GSI started to increase from February
and attained the maximal value in May, decreased in
June corresponding to their spawning season (Table
I). The second spawning season was prolonged; it
started from August till November with the peak
value of gonado-somatic index in September.
GONAD’S DEVELOPMENT AND FECUNDITY OF SAILFIN MOLLY
171
Table I.-
Frequency of occurrence (percent) of different maturation stages for male and female of P.1latipinna in different
months.
2
Months
No. of
fishes
I
12
9
7
6
6
13
8
7
8
6
7
10
9
9
7
16.67
0.00
0.0
0.00
16.67
23.08
12.50
0.00
0.00
0.00
71.43
10.00
0.00
11.11
14.29
3
Feb 2003
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan 2004
Feb
Mar
Apr
Maturity stages in male
II
III
IV
25.00
0.00
0.00
0.00
66.67
30.77
0.00
0.00
0.00
0.00
28.57
40.00
0.00
11.11
14.29
25.00
22.22
0.00
0.00
16.67
38.46
12.50
14.29
25.00
16.67
0.00
40.00
44.44
22.22
14.29
16.67
222.22
42.86
0.00
0.00
7.69
12.50
14.29
25.00
16.67
0.00
0.00
22.22
22.22
28.57
V
No. of
fishes
I
16.67
55.56
57.14
100.00
0.00
0.00
62.50
71.43
50.00
66.67
0.00
10.00
33.33
33.33
28.57
10
13
15
16
16
9
14
15
14
16
15
13
14
13
15
20.00
0.00
33.33
0.00
62.50
33.33
7.14
0.00
0.00
6.25
40.00
61.54
0.00
0.00
20.00
Maturity stages in female
II
III
IV
70.00
38.46
0.00
6.25
12.50
11.11
0.00
13.33
0.00
0.00
13.33
0.00
35.71
15.38
13.33
0.00
7.69
13.33
6.25
6.25
22.22
7.14
6.67
21.43
12.50
6.67
15.38
42.86
7.69
13.33
0.00
23.08
13.33
12.50
6.25
33.33
28.57
6.67
28.57
25.00
20.00
15.38
14.29
30.77
20.00
V
10.00
30.77
40.00
62.50
6.25
0.00
57.14
73.33
50.00
56.25
20.00
7.69
7.14
38.46
33.33
4
Sex ratio
Data of monthly changes in the sex ratio are
presented in Figure 2. Generally, the females were
higher in numbers than males during the whole
period of the study except in February and July.
Length at first maturation and 50% maturation
The total length of smallest specimens of P.
latipinna netted from Wadi Haneefah Stream was
39 mm (male) and 45 mm (female). They achieved
the first maturity at total length of 51 mm and 48
mm (male and female, respectively). It is registered
that 50% of the fish matured at the length of 65 mm
(male) and 67 mm (female). Both male and female
fish at around 80 mm of body length showed 100%
maturation in active reproductive periods (Fig. 3A
and B).
Fecundity
The observed and calculated fecundity of P.
latipinna, on the basis of length, ranged between 35
- 161 and 29.03 - 185.95 eggs respectively. The
relative fecundity in relation to length ranged
between 0.55 - 2.05 (egg/mm), whereas the range in
relation to weight was 2.10 - 13.30 (eggs/g).
Logarithmic relationship between the mean
length and absolute or calculated fecundity is
represented in Figure 4 A & B. The relationship
obtained was as follows: Log F = - 3.112 + 2.721
Log L, whereas the correlation coefficient (R) is
0.67 which showed a significant relationship.
Similarly, Figure 5 A and B shows the
relationship between wet body weight of the fish
and absolute fecundity as follows: Log F= 1.049
+1.11 Log W, with significant correlation
coefficient (R = 0.85).
The relationship between mean weight and
calculated fecundity is as follows: Log F = 1.049 +
1.114 log W. This relationship is highly significant
(correlation coefficient, R = 1.0).
Regression analysis of total weight with
absolute fecundity and relative fecundity of P.
latipinna indicated that absolute fecundity has a
good relation with total weight (r=0.64) and total
length (r=0.56).
DISCUSSION
Limitations of breeding to a particular season
was postulated for temperate zone fishes where the
habitat is dominated by pronounced annual cycles of
photoperiodicity, thermal variations and food
availability (Bagenal and Erich,1978; Scott, 1979).
Continuity of breeding seems well suited the
tropical freshwater fishes where the stability of
essential conditions tend to prevail for most of the
year.
A.S. AL-AKEL ET AL.
172
Spring
(Male)
Summer
Fall
(Female)
Winter
(Combined)
Gonadosomatic index
30
25
20
15
10
5
0
0
Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr
Months
1
Fig. 1. Monthly changes in gonadosomatic indeces of males, females and combined sexes of P2
.
Wadi Haneefah stream,Riyadh.
3
4
Spring
Male
100
Summer
Fall
latipinna in
Winter
Female
Sex ratio (%)
80
60
40
20
0
0
Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr
Months
Fig. 2. Sex ratio in (percent) of P. latipinna in Wadi Haneefah stream, Riyadh.
5
6
7
GONAD’S DEVELOPMENT AND FECUNDITY OF SAILFIN MOLLY
173
8
100
2.50
(A) Lt50 =67mm
2.25
Log10 observed fecundity
percent maturation
90
80
70
60
50
40
Log F = - 3.112 + 2.721 Log L , R = 0.67
(A)
2.00
1.75
1.50
1.25
1.6
30
45 50 55 60 65 70 75 80 85 90 95 100
1.7
1.8
1.9
2.0
2.1
2.0
2.1
Log10 mean length (mm)
Total Length (mm)
2.50
100
(B) Lt50=69mm
Log10 calculated fecundity
90
percent maturation
80
70
60
50
40
30
2.25
(B)
2.00
1.75
1.50
1.25
1.6
20
Log F = - 3.112 + 2.721 Log L , R =1.0
1.7
1.8
1.9
Log10 mean length (mm)
10
45
50
55
60
65
70
75
80
85
90
Total length (mm)
Fig. 3. Relationship between total length
and percentage of matured females (A) and
males (B) of P. latipinna.
Fish ovaries showed periodic seasonal
changes in weight. In the present work, the monthly
changes in gonado-somatic-index indicated two
prolonged seasons; the first spawning season
extended from February till May, the GSI started to
increase from February, attained the maximal value
in May and then decreased sharply in June. The
second spawning season was longer; it started from
July till November with a peak in September. This
observation coincides well with stage V (mature
fish) found from February to May and August to
November, and corresponds to the period of reduced
water level and high availability of food (Al-Kahem
et al., 2007).
Fig. 4. Logarithmic relationship between
length and observed (A) and calculated
fecundity (B) of P. latipinna in Wadi Haneefah
stream, Riyadh.
Welcomme (1979), Tomasson et al. (1984)
and Townshend and Wooton (1984) have studied
the spawning of P. latipinna and suggested that
flooding, water current, elevated silting, lower
visibility and availability of breeding ground as well
as food may trigger or induce breeding in fishes.
The reduced reproductive activities of Poecilia
latipinna in June, July , December and January is
probably related to above mentioned factors. A
concentrated reproductive efforts in the months
which witnesses minimum discharge is reported for
subtropical stream dwelling fishes (Milton and
Arthington, 1985) and this is acceptable in the sense
that larvae produced at this time were less likely to
experience high mortality than during elevated flow
(Pusey et al., 2001).
A.S. AL-AKEL ET AL.
174
Log10 observed fecundity
2.50
2.25
Log F = 1.049 + 1.114 Log L , R = 0.85
(A)
2.00
1.75
1.50
1.25
0.25
0.50
0.75
1.00
1.25
1.00
1.25
Log10 mean weight (gm)
Log10 calculated fecundity
2.50
2.25
Log F = 1.049 + 1.114 Log L , R = 1.0
(B)
2.00
1.75
1.50
1.25
0.25
0.50
0.75
Log10 mean weight (gm)
Fig. 5. Logarithmic relationship between
weight and observed (A) and calculated
fecundity (B) of P. latipinna in Wadi Haneefah
stream, Riyadh.
The sex ratio indicates the proportion of
males with females in the population which is
expected to be 1:1 in nature. This type of study
indicates segregation or aggregation of sexes
according to feeding, breeding and migratory
behaviour. Previous studies indicate that the females
dominate over males (Bhatt, 1972; Thompson and
Munro, 1978; Ghorab et al., 1986; Zabala et al.,
1997). Equal number of males and females were
reported by Yabe (1954). Disparities in assumed sex
ratio (1:1) were also reported by Marr (1948), Wade
(1950) and Raju (1963). Domination of females
over males in all the months except in the peak
spawning period was reported by Hashim and
Salamah (1985) and Coleman et al. (1996). Tamaru
et al. (1996) have reported that male of Epinephelus
microdon dominates (4:1) over female. In the
present study females outnumber males in all the
months of the year. The variations in the sex ratios
depend mainly upon the size of the samples
analyzed, spawning migration, exploitation, weather
condition at the time of catch, gear used and sex
reversal (Batts, 1972; Thomson and Munro, 1978;
Hashim and Salamah, 1985; Ghorab et al., 1986).
Majority of fishes are oviparous but few like
sharks and guppies (live bearer) are ovo-viviparous.
Parental care is apparent in ovo-viviparous fishes as
they produce little number of eggs. On the other
hand, oviparous fishes are more fecund (produce
more eggs) probably because of the less survival
chance due to environmental hazards. The
detrimental effect of this low fecundity is probably
mitigated by parental care behaviour which is a
common feature of molly, P. latipinna (Moyle and
Cech, 1982). This parental care behaviour and low
fecundity was also reported in gobiis,
Economidichthys pygmaeus and Crystallogobius
linearis by Daoulas et al. (1993) and Caputo et al.
(2003), respectively, and extend considerable
support to present investigation.
Hence, the energetic investment in
reproduction tends to be higher, where the smaller
fishes spend more energy on growth thus producing
less and smaller eggs (Moyle and Cech, 1982; AlDhahi, 2000). Results of Ghorab et al. (1986) and
Al-Dhahi (2000) indicate that the environmental
conditions also affect the fecundity of fishes as E.
chlorostigma have different fecundity in two
different environments (Red Sea and Arabian Gulf).
ACKNOWLEDGEMENT
The Center of Excellence in Biodiversity
Research (CEBR), College of Science, King Saud
University is greatly appreciated for extending the
financial support for the execution of this research
work.
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(Received 14 April 2009, revised 28 July 2009)
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