Transcript SOME ECOLOGICAL PARAMETERS OF AND THEIR USED IN RESOURCE EXPLOITATION

SOME ECOLOGICAL PARAMETERS OF
ARTEMIA PARTHENOGENETICA GAHAI
AND THEIR USED IN RESOURCE
EXPLOITATION
• Author:
Sun Jingxian
Dalian Fisheries University
Dr. Jia Qinxian
Research Center for Salt
Lakes,Chinese Academy of
Geological Sciences
Academician. Zheng Mianpin
Research Center for Salt
Lakes,Chinese Academy of
Geological Sciences
SOME ECOLOGICAL PARAMETERS OF
ARTEMIA PARTHENOGENETICA GAHAI
AND THEIR USED IN RESOURCE
EXPLOITATION
Theme:
• Brine shrimp eggs is the indispensable ringent bait for the
marine animal breeding .Gahai Salt Lake has an abundant
Artemia resource, which should be utilized under reasonable
exploitation.
• Based on the annual water temperature regime of Gahai Saltlake，
forecasting the productivity of the population, estimating the
potentiality of the resource exploitation.
MATERIALS
• Brine shrimp eggs – collected from Gahai Salt Lake.
• The adults and larvae of Artemia – hatched from
dormant eggs.
• Bait – Dunaliella sp., Phaeodactylum tricornutum
and marine Chlorella sp.
• Salt water – 60‰ salinity.
METHODS AND FORMULAE
• The setting of the experimental conditions: Except for
temperature, the conditions(salinity, bait or etc) were consistent with the
nature.
– Temperature: Between 16 and 34℃ at intervals of
2℃,with errors of ±0.3 (the temperature was controlled
by ICL-216 temperature controller*, ”*” see remark).
– Salinity:
Fixed at 60‰.
– Illumination: Natural light.
– Breed density: 1000 nauplii were added to each culture
chamber filled with 2 liters of salt water (60‰).
Methods and Formulae (con.)
Threshold temperature of development(C)
Constant of effective accumulative temperature(K)
• Based on K=N(T-C),finding the roots by using least square method.The
equations are as follows:
Vj = 1/Nj
Vi =（∑Vj/n）=1/（∑Nj/n）= n/∑Nj
k = ( m r∑ViTi∑Vi∑Ti) /m r∑Vi2 (∑Vi)2
C = (∑Vi2∑Ti∑Vi∑ViTi) / m r∑Vi2 (∑Vi)2
R = (∑TiVi∑Ti∑Vi/m r) / SQR [(∑Ti2(∑Ti)2/m r)(∑Vi2(∑Vi)2/m r)]
i = 1,2,…,mr
Degrees of freedom (df) = mrr2 ) = 15222 = 26
where:
Nj -- development time (d) of the jth sample;
Vi -- mean development rate (d-1) ;
Ti -- experimental temperature (℃);
k -- constant of effective accumulative temperature of a generation (C
degree-days);
r -- times of repetition at m experimental temperatures;
C -- threshold temperature of development (℃);
R -- correlation coefficient;
n -- number at each temperature.
Methods and Formulae (con.)
TEST OF LIFE TABLE
• Mean generation time (T), population net reproduction
rate(Ro) ,intrinsic rate of natural increase (rm) , infinite rate of
increase () and doubling population time (t) were calculated
by the following equations (Wu et al.1991) :
T = (∑lxmxX)/ (∑lxmx)
Ro = ∑lxmx
rm = loge Ro / T
 = exp(rm)
t = loge 2/ rm
where:
X -- age (day);
lx -- survival rate at X age;
mx -- output female offspring number per female
adult at X age.
Methods and Formulae (con.)
THE DEFINITION FOR GENERATIONS
• Y = f(X):
– The distributing time (X,day) as abscissa,the water temperature
(Y,℃) as ordinate, getting the regression equation f(X).
– Counting the temperature above the threshold temperature of
development for larvae ,calculating the range of effective time [0,t]
b
•
 f (X )  A :
a
– Object function (A)
– The lower limit (a)
– The upper limit (b)
Or set a=0, get b; set a=b, get new b; if b>t, the calculation is finished,
otherwise repeat calculation.
where: X= distributing time (day)
b
•  f (X )  A
a
Using the mean effective accumulative temperature of a
generation as an object function (A). The growth initiation
time of the first generation as the lower limit. The upper
limits were calculated with a definite integral equation.
Subsequently, using the upper limit as the lower limit of
the next generation, we calculated upper limits repeatedly
to the time of the borderline of each generation in the range
of [0,t]:
RESULTS
•
Temperature adaptability and requirement of the
quantity of heat for development
•
Life Table on Age Character
•
Ecological Parameters and Water Temperature
•
Population Productive Potential and Water
Temperature
– Generations and Water Temperature
– Population Productive Potential
Result (con.)
Temperature adaptability and requirement of the
quantity of heat for development
Table1: Influence of temperature on the mean development rate of Artemia
The larva(d)
Whole life time(d)
Mean generation
time(d)
3.87±2.04
47.13±9.90
112.13±42.70
85.66
19
2.95±1.65
30.31±5.75
96.31±28.89
71.94
22
2.04±0.58
22.47±2.40
76.17±14.47
60.70
25
1.52±0.59
17.80±1.42
61.05±11.60
48.98
28
1.29±0.32
14.33±1.00
57.53±6.78
38.44
31
1.12±0.22
12.01±0.90
50.11±5.51
25.53
34
0.97±0.15
11.80±1.12
42.60±7.26
21.17
r
0.998
0.992
0.967
C(℃)
9.94
10.33
10.28
K(℃•d)
22.91±2.08
Temperature
(℃)
Hatching(d)
12
12.04±7.82
16
261.26±24.10
458.68±57.6
• r -- correlation coefficient
• C -- Threshold temperature of development
• K -- Constant of effective accumulative temperature
Temperature adaptability and requirement of the
quantity of heat for development
• We recorded the development rate on each development
stage of Artemia at 8 temperatures, as Table 1 shows. The
close relationship between the mean development rates and
temperature was shown by their correlation coefficient.
• We can clearly see that the development rates for hatching,
nauplius, larvae, and adults were obviously shortened with
elevated water temperature and so did the mean generation
time.
• By calculations, the threshold temperature of development
(C) and the effective accumulative temperature(K) for
hatching were 9.94℃ and 22.91℃·d, respectively. for the
larva were 10.33 ℃ and 261.26℃·d, respectively, and for a
whole generation were 10.28℃ and 458.68℃·d,
respectively.
Result (con.)
Life Table on Age Character
Table 2: Life table of Artemia on age character
Temperature(℃)
eggs
larvae
hypo-adults
adults
male
reproductive rate
population
reproductive times
death rate before
adult
16
1000
371.25
108.5
84.00
0
65.21
5.481
19
1000
461.00
185.75
147.25
0
79.08
11.658
22
1000
582.75
352.75
281.50
3
86.65
24.13
25
1000
642.75
340.00
285.75
4
160.09
45.10
28
1000
728.25
413.00
322.25
7
157.70
49.55
31
1000
514.50
232.50
206.00
6
129.70
25.94
34
1000
347.00
67.00
56.25
6.25
38.5
1.925
91.6
85.275
71.85
71.425
67.775
79.40
94.375
Table 3: Daily reproductive rate of Artemia
19 ℃
25℃
34℃
mean generation time(d)
71.9
49.0
21.2
reproductive rate
79.1
160.1
38.5
daily reproductive rate
1.10
3.27
1.81
Life table on age character
• Constructing a life table of Artemia at seven temperatures.
The amount of eggs, larvae, adults were counted, and the
survival rate, reproductive rate were recorded. (As Table2
shows)
• The death rate before adult marked the adaptability of the
population to the environment. The death rate was high at
either the higher or lower test temperature,low at the range
of 22-28℃. Fitting the death rate with temperature,we got
the temperature range for development from larvae to
adults.The range is 10.10-39.56℃.
Life table on age character
• The population reproductive times reflected the population
potentiality of reproduction. Fitting the population
reproductive times with temperature,we got that the
population have potentialities of increase at the range of
13.95-35.75 ℃. The maximal potentialities of increase is at
24.85 ℃.
• Putting the mean generation time and reproductive rate of
each female Artemia together, we get daily reproduction.
(As Table3 shows) Because of shorter generation time at
higher temperature, daily reproduction was higher, and
both total reproductive rate and daily reproduction reached
the highest values at the optimum temperature.
Result (con.)
Some Ecological Parameters of Artemia and Water
Temperature
Table 4 Main ecological parameters of Artemia in different temperature
Temperature
rm(ind.／♀.d)
T(d)
Ro(Nt／No)
λ(/d)
t(d)
16
0.01774
85.66
4.572
1.0179
39.073
19
0.02999
71.938
8.652
1.0304
23.112
22
0.05091
60.702
21.995
1.0522
13.616
25
0.08578
48.980
66.811
1.0896
8.081
28
0.10842
38.444
64.602
1.1202
6.393
31
0.12749
27.530
33.441
1.13597
5.437
34
0.07643
21.171
5.043
1.0794
9.069
Regression
equations
Ro＝ exp(-16.15491十1.56271X－0.03028X2 )
rm ＝ exp(-11.13956十0.59790X－0.01005X2 )
λ＝ exp(－0.32958十0.02827X－0.00046X2 )
t ＝ 170.0153—11.3905X十0.1962X2
T ＝ 37.4685X exp(－0.1197X)
F(2.4)=13.99
F(2,4)=57.49
F(2.4)=9.20
F(2,4)=298.58
F(1,5)=2447.7
Some Ecological Parameters of Artemia and
Water Temperature
• Based on the observation of the process from
hatching of eggs to death of adults, the life table of
Artemia at seven temperatures were set up. The
intrinsic rate of natural increase (rm) , mean
generation time (T),the reproduction rate (Ro),
finite rate of increase () and the doubling time of
population increase (t) of Artemia under different
temperature were calculated. The results obtained
are as Table4.
•
The regression equations of the 5 parameters
with temperature were listed in the table.
Result (con.)
Generations and Water Temperature
• Water temperature data from Gahai Saltlake,during
1993-1994 and Jul-Aug in 1997.
• The total effective accumulate temperature is
1225.66 ℃·d
• Mean accumulate temperature of generation is
458.6857.6 ℃ -- as an object function value(A)
• The theoretical number of generations is 2.67±0.34
per year.
• The threshold temperature is 10℃.
Generations and Water Temperature
• Fitting time distribution with water temperature and got equation:
Y= 0.3066X0.001179X2
Y= -10+0.3066X0.001179X2
(F(2,6)=99.94**)
(F(2,6)=99.94**)
(1)
(2)
where: Y= temperature(℃) ; X= generation time(d)
e(℃)
Temperature( ℃
)
• Dividing the generation time:
25
20
15
10
Ⅰ
25/4
5
Ⅲ
26/8 Ⅲ’
Ⅱ
10/7
23/10
10/8
0
0
17/3
50
100
150
Generation time (d)
200
250
30/11
300
Fig.1 The generations of Artemia and environmental temperature in Gahai Salt Lake
Ⅰ~ Ⅲ = 1st to 3rd generations ; Ⅲ’= last whole generation
–
The beginning time of each generation:
GenerationⅡ,Jul 10; Generation Ⅲ ,Aug 26; The last whole generation,
Aug 10.
Generations and Water Temperature
In order to determine the time borderlines for each generation,
we further fit time distribution with water temperature and got
equation 1,when water temperature was above 10℃ got equation
2.
The definition of the border line of each generation time
calculated from the definitive integral equation was shown in
Figure 1
When the temperature was over 0℃ in equation 1, the range
of time was from 0 to 260(or from March 17 to November 30).
The 2nd ~3rd generation began on Jul 10, Aug 26,
respectively. The last whole generation began on Aug 10.
Generations and Water Temperature
Time of Reproductive Peak
Temperature( ℃ )
25
20
Ⅱ
Ⅲ
17/7
3/8
Ⅰ
15
18/6
Ⅳ’
Ⅳ
1/9 12/9
10
20/4
5
27/10
30/11
0
17/3
0
50
100
150
200
250
300
Fig.2 The reproductive peak time of Artemia in Gahai Salt Lake
Ⅰ~ Ⅴ = 1st to 5th reproductive peak ; Ⅴ’= reproductive peak in last whole generation
– The reproductive peak number is 4.69±0.43 per year.
– Peak of nauplii in first generation was on April 20th~28th.
– Last reproductive peak on September 12th~17th.
– * Reproductive peak in last whole generation on september 1st. The
nauplii hatched after September 1st can not complete the development
from nauplii to adult, because of insufficient habitat effective
accumulative temperature. (”*” see remark)
Result (con.)
Population Productive Potential
BASED ON
• The changes of water temperature with time(Eq.1)
• The relationships between parameters and temperature(Table.4)
The rm ，Ro， T ， and t were converted into the relation of time
distribution.
THE RESULT INDICATE：
July 11th to September 20th
• t <30d
• rm >0.02 d-1.
high productivity
July 11th to September 20th
the best season for
commercial exploitation
CONCLUSIONS
• These methods of estimating the potentialities for
exploitation are only available to the lake(like Gahai
Saltlake) with broad area and deep depth.
• The generation of Artemia were closely in relation to
water temperature.
• The diapause eggs of the last generation after the
middle Sep can only be exploited appropriately.
• The eggs before the middle of Jul should be banned.
How to establish the strategy of exploitation
• Banning the exploitation of Artemia eggs -- before the
middle of Jul
– The first generation in a year comes from the overwintered
eggs,and the population size is limit without complementary until
sex-mature. In first generation,the peak of nauplii was on April
20th~28th,the sex maturation was during the first twenty days of
Jun. In order to keep the quantity of the population for
sustainable increase,the eggs before the middle of Jul should be
banned.
• Exploiting the diapause eggs appropriately -- after the
middle of Sep
– The last reproductive peak was on September 12th~17th.
Because the last generation provides the basis of producing first
generation of next year,to assure enough eggs for the
population of next year, the diapause eggs of the last generation
after September 12th~17th can only be exploited appropriately.
• We also limit the time for exploitation by the
environmental variation model,which reflected the
annual variations of water temperature,salinity
and baits in Gahai Saltlake.(the model will soon be
published)
Thank you