全 文 ：渤 海 生 态 通 道 模 型 初 探 3
仝　龄 3 3 　唐启升　(中国水产科学研究院黄海水产研究所 ,青岛 266071)
Daniel Pauly 　(加拿大卑诗大学渔业研究中心)
【摘要】　生态通道模式 ( Ecopath Model)是一种较为方便地研究生态系统结构 ,特别是水域生态系统结构的工
具. 它根据能量平衡原理 ,用线性齐次方程组描述生态系统中的生物组成和能量在各生物组成之间的流动过
程 ,定量某些生态学参数 ,如生物量、生产量/ 生物量、消耗量/ 生物量、营养级和生态营养效率 ( EE , Ecotrophic
Efficiency)等. 它能够给出能量在生态通道上的流动量 ,便于对生态系统的特征和变化作深入的研究. 本文主要
根据 1982～1983 年渤海生态系统综合调查的渔业资源基础数据 ,建立了渤海生态系统初步生态通道模型. 根
据食性关系特点 ,渤海生态系统 Ecopath 模型由 13 个功能组 (Box) 构成. 它们是小型浮游动物、大型浮游动物、
小型软体动物、大型软体动物、小型甲壳类、大型甲壳类、草食性鱼类、小型中上层鱼类、底层鱼类、底栖鱼类、中
上层顶级捕食鱼类、浮游植物和有机碎屑. 功能组的划分 ,基本上可以覆盖渤海生态系统中生物能量的主要流
动过程. 模型采用每平方公里吨/ 年为主要参数单位 ,大部分功能组的生产量与生物量比值 ( P/ B) 和消耗量与生
物量比值 (Q/ B)参数主要是根据相同纬度水域 Ecopath 模型中类似的功能组估算得到. 在调试渤海生态通道模
型时 ,考虑渤海生态系统是一个生态转换利用充分的水域 ,生态营养效率 ( EE) 的值均取在 0. 808 以上. 模型估
算出渤海可利用经济种类的生物量达到 95 ×105 t (每平方公里 12. 3t·km - 2) ,其中鱼类资源生物量为 33. 8 ×
105 t . 上述数值比渤海生态系统综合调查结果数据和其它有关文章发表的渤海资源生物量 (多根据拖网调查资
料)的数值要高 ,其中小型中层鱼类生物量为渤海综合调查生物量的 1. 8 倍. 考虑到拖网调查方法往往对生物
资源量估计偏低 ,可以认为渤海生态通道模型对生物量的评估数据是合理的.
关键词 　生态通道模型 　营养动力学模式 　渤海生态系统 　生物资源评估
A preliminary approach on mass2balance ecopath model of the Bohai Sea. TON G Ling , TAN G Qisheng ( Yellow
Sea Fisheries Research Institute , Chinese Academy of Fisheries Sciences , Qingdao 266071) , Daniel Pauly ( Fisheries
Cent re , U niversity of B ritish Columbia 2204 M ain M all , V ancouver , B . C. , V 6 T 1 Z4 , Canada) . 2Chin. J . A p2
pl . Ecol . ,2000 ,11 (3) :435～440.
A Bohai Sea mass2balance ecopath model is constructed on the basis of fisheries resources data from the ecosystem sur2
vey conducted from April 1982 to May 1983. It is the first ecopath model which consists of 13 function groups (box2
es) , and only covers the main trophic flow in the Bohai Sea ecosystem. P/ B and Q/ B parameters ( P :production , B :
biomass , Q :consumption) for most groups were estimated from similar function groups in other ecopath models of the
same latitude regions around. The value of EE ( Ecotrophic Efficiency) is the main parameter to check the equilibration
of the model. The EE parameters in the model are of high value ( > 0. 808) for most groups , because the fishing pres2
sure was very high and small living organisms were being heavily preyed upon in the ecosystem. The biomass density of
the species commercially utilized estimated by the model is 12. 33 ton·km - 2 . Even though the value is low compared
with the density in other ecosystems , such as Caribbean coral reef ecosystem and the Southern B. C. shelf model , it is
higher than the value published by some papers on the Bohai Sea using other methods. Considering the lower value es2
timated by the stock assessment using bottom trawl survey data , the output here is reasonable. It is concluded that the
biomass of commercial fishing species in the sea is 950 thousand metric tons , and 338 thousand tons are fish species in
the value.
Key words 　Ecopath model , Trophic dynamics modeling , Bohai Sea ecosystem , Stock assessment .
　　3 国家自然科学基金重大资助项目 (497901001) . The research was
supported by the Key Project ,No. 49790100 ,National Natural Science Foun2
dation of China.
　　3 3 通讯联系人. Corresponding author.
　　Received 1999 - 06 - 28 ,Accepted 1999 - 12 - 21.
1 　Introduction
The Bohai Sea is a semi2closed continental sea of
China , which is nearly encircled by land only with a
mouth about 90 km at the eastern apex that connects it
to the Yellow Sea ( Fig. 1) . The area of the sea is 77000
km2 and the average depth of 18. 7 m. Water tempera2
ture changes a lot resulting from the impact of the land
climate. The highest SST is 26～ 30 ℃ in September
and the lowest one is 1. 2～4 ℃in February. The sea is
an ocean space with distinct productivity , st rong fishing
activity and complicated relationship of food web. It is
also polluted heavily by industry and living sewage re2
cently.
　　The Bohai Sea ecosystem depends on the amount of
应 用 生 态 学 报 　2000 年 6 月 　第 11 卷 　第 3 期 　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　
CHIN ESE JOURNAL OF APPL IED ECOLO GY ,J un. 2000 ,11 (3)∶435～440
Fig. 1 Map showing the Bohai Sea ecosystem region.
solar energy input and the organisms imported from sev2
eral rivers. NO -3 2N and PO +4 2P are basic nutrients sup2
porting the primary productivity in the sea. The organic
carbon is 112gC·m - 2·yr - 1 . The productivity is charac2
terized by a seasonal and spatial variety with high level
in spring and fall in the sea , but no much change be2
tween years. In the Bohai Sea , dominant small zoo2
plankton are neritic brackishwater species , such as
S agit ta crassa , L abi docera euchaeta and Cent ropages
mcm urrichi [3 ]. The fishing effort in the sea has been
increasing more and more since 1962 , which led to a
significant variation in the abundance and dist ribution of
the most species in the area. The resources composition
in the Bohai Sea changed a lot along with the increase of
fishing effort to multi2species fish communities after
1962. The CPU E (catch per horse power) was 7. 61
ton in 1962 , but it went down to 0. 88 ton in 1983.
The traditional species fished in the area , such as small
yellow croaker , slender shad , cutlasfish , were high
valuable in the market , but the biomass of them de2
clined then. The small pelagic fish and small crustacean
species appeared much more in the landings and fluctu2
ated much annually. The highest annual landing of
A cetes reached 100 hundred metric tons (1. 3 t·km - 2)
in the sea. The highest catch of jelly fish was 280 hun2
dred tons during the 1970s. This reflects a gradual t ran2
sition in catch from long2lived , high trophic level , pis2
civotous bottom species toward short2lived , low trophic
level invertebrates and planktivorous pelagic species[12 ] .
The sea is an example of the ecosystem overfished to2
ward smaller , high2turnover species exploited. It is a
remark of Bohai Sea that small pelagic fish and jellyfish
replaces large table fish as an over2exploited ecosys2
tem[13 ] .
2 　Methodology and Ecopath Model
The approach of Ecopath model was originally de2
scribed on coral reef ecosystem by Polovina[14 ] and was
further developed by V. Christensen and D. Pauly[1 ] to
make it available in a well2documented software running
widely. Lately the Ecopath model developed to a new
integrated Ecopath with Ecosim software for dynamic
simulation modeling based on mass2balanced model by
C. Walter [17 ] . In Ecopath model it is assumed that the
ecosystem modeled is in steady state for each of the liv2
ing groups , which implies that input equals output , i . e.
Q = P + R + U , where Q is consumption , P pro2
duction , R respiration , and U unassimilated food. The
above equation can be structured around a system of lin2
ear equations for expressing mass2balance with the sim2
plest form. It can be expressed for an arbit rary time pe2
riod and for each element i of an ecosystem by the for2
mula :
B i·( P/ B ) i·EEi = ∑
k
j = 1
B j·( Q/ B) j·DCij - EX i
where B i is the biomass of function group i during the
period covered (conventionally , a year) ; ( P/ B ) i pro2
duction/ biomass rate ; EEi ecotrophic efficiency , i. e. ,
the f raction of the production that is utilized within the
system for predation or export ; Ci , the fish catch ; B j ,
the biomass of the predator j to prey i ; ( Q/ B ) i , the
relative food consumption ratio of i ; and DCij is the
f raction of prey i in the diet of predator j . The simulta2
neous linear equations using in Ecopath model states that
the production and consumption are balance within an e2
cosystem.
The Ecopath model allows rapid construction and
verification of a mass2balance model on ecosystem. The
result of the model does not only verify the previously
published biomass estimates , but also identify the
biomass required for assessment of marine carrying ca2
pacity. To construct an Ecopath model can consist main
of the following steps. (1) Identification of the area and
period for which the model will be constructed on an e2
cosystem ; (2) Definition of all functional groups ( box2
es) , f rom primary producers to top predators in the e2
cosystem , to be included for the thermodynamic bal2
634 应 　用 　生 　态 　学 　报 　　　　　　　　　　　　　　　　　　　11 卷
ance ; (3) Setting parameters of production/ biomass ra2
tio ( P/ B ) , consumption ratio ( Q/ B ) , biomass ( B )
and ecotrophic efficiency ( EE) for each function group ,
but only three of them are necessary as the basic input
parameters in the model and also entry of the catches to
every fishing species ; (4) Entry of a diet consumption
matrix ( DC) expressing the diet f raction of predator/
prey relationship in the model ; (5) Modify the entries of
P/ B , Q/ B , EE or the biomass to balance the Ecopath
model ( repeating above ( 3) and ( 4) steps) until the
mass input equals output for each box.
The Kyoto Conference held in Japan in 1995 pro2
moted a strengthened scientific basis for multi2species
and ecosystem management to fisheries. Probably the
most comprehensive of the approaches is Multi2Species
Virtual Population Analysis ( MSVPA) , but the major
drawback of MSVPA is that it requires a large amount
data for application , including long time series of age in2
formation. Ecopath model relies on much less data and
hence to be applicable in a much wider range of fisheries
systems[11 ] . In recent years , several workshops on Eco2
path approach were held , which led to nearly 100 Eco2
path models applied in the world. The Ecopath with the
latter category of Ecosim and Ecospace has a potential
uses in ecosystem management [10 ] .
3 　The Bohai Sea Ecopath Model and Its Results
The Ecopath model of the Bohai Sea is going to
construct a quantitative description of t rophic st ructure
on the ecosystem. The model can be used to estimate
some important biological parameters and the relation2
ship among the different groups in the Bohai Sea. The
model is based on the month data f rom the bottom
trawling of the Bohai Sea ecosystem survey project com2
pleted during April 1982 to May 1983 [4 ] . It only pre2
sents a preliminary revelation of the trophic st ructure
and flow in the sea between different function groups.
The function group determination , like other Ecopath
models , is based on the species feeding behavior ,dist ri2
bution and the function in the ecosystem. The function
definition is little different with the taxonomy and the
group name is only the designation in the model. All
groups in the model cover the main trophic flows among
the living marine groups and detritus.
The Ecopath model is the first mass2balance model
in the Bohai Sea. It only has 13 function groups based
on stomach contents inspection of 54 species f rom 1863
samples f rom the Bohai Sea survey[5 ] . The definition of
function group is very rough because of the limited type
of survey data available in the region. One primary pro2
ducer of phytoplankton was identified. Zooplankton was
split into two groups , microzooplankton and macrozoo2
plankton. The former includes small herbivorous and
carnivorous zooplankton and the latter mainly consists of
jellyfish and A cetes . Benthic invertebrates were divided
into small mollusca , large mollusca , small crustacean
and large crustacean , most of which were commercial
harvest in the sea but landing data were not well avail2
able. No biomass data for the species in the small inver2
tebrate groups so the biomass was estimated by the
model using the fixed ecotrophic efficiency ( EE =
0. 95) . Biomass for the two large groups were obtained
by summing up the biomass data f rom the survey[6 ] .
Five fish function groups were identified in the model on
the basis of 31 fish species which hold about 90 % of to2
tal biomass for the fish community in the Bohai Sea.
Herbivorous feeders group includes mainly M ugil
cephal us and L iz a haem atocheila. Other four groups
were small pelagic fish , demersal fish , benthic feeders
and top pelagic feeders , which were important commer2
cial fishing target [7 ] . The details of 13 function groups
(box) in the Bohai Sea Ecopath model are summarized
in the Table 1.
　　It is hard to find P/ B and Q/ B f rom one species
to the whole group because many species are included in
one function group in the model. We set the P/ B and
Q/ B parameters in Bohai Sea model based on the ones
f rom similar function group in the models of the Strait
of Georgia by Dalsgaard , the Brunei Darussalam , South
China Sea[16 ] and the Georges Bank[15 ] . The basic pa2
rameters of biomass (wet weight t·km - 2 ) , P/ B , Q /
B , EE and harvest for the 1982～1983 Ecopath model
of the Bohai Sea ecosystem are presented in the Table 2 ,
while the Table 3 shows the corresponding diet matrix.
The detritus is estimated on the basis of the primary
production of Carbon by the equation A5 of the empiri2
cal relationship method[9 ] . Phytoplankton is estimated
from the Bohai Sea primary productivity of 112 gC·m - 2
·yr - 1 , which were converted to g wet weight phyto2
plankton m - 2·yr - 1 by a wet weight :carbon ratio of 10∶
1. The ratio is used by several papers on Ecopath model ,
like Alaska gyre Ecopath model[10 ] .
　　To balance import to and out f rom every box , the
EE values are leading check parameters for equilibration
7343 期 　　　　　　　　　　　　　　　　　　仝 　龄等 :渤海生态通道模型初探 　　　　　　　　　
Table 1 Main species checklist of function groups in the Bohai Sea ecopath
model
Microzooplankton
　　Copepoda ( L abidocera euchaeta , Calanus sinicus , Paracalanus
parv us) , Mysidacea , S agitta sp . , Fish eggs
Macrozooplankton
　　Acetes chinensis , Jellyfish
Small mollusca
　　A rca subcrenata , Phili ne kinglipini , Chlamys f arreri
Large mollusca
　　 Sepiella maindroni , Octopus ocellat us , Octopus variabilis , L oligo
japonica , L oligo beka
Small crustacea
　 　 Trachypenaeus curvi rost ris , A lpheus japoncus , Oratosquilla
oratoria , Palaemon gravieri , Crangon sp .
Large crustacea
　　 Penaeus chinensis , Port unus t rit uberculat us , Charybdis japonica
Herbivorous feeders
　　 M ugil cephal us , L iza haem atocheila
Small pelagic f ish
　　 Engraulis japonicus , Setipinna taty , Coilia myst us , Harengula
z unasi , Thrissa kam m alensis , Clupanodon punctat us
Demersal f ish
　 　 Pseudosciaena polyactic , L ateolabrax japonicus , Collichthys
lucidus , Collichthys niveat us , S t romateoides argenteus , A rgyrosom us
A rgentat us , Nibea albif lora , Johni us belengeri , A pogonichthys li neat us
Benthic feeders
　　 Raja porsa , Raja pulchra , Cynoglossua joyneri , Enchelyopus
elongat us , Pseudopleuronectes yokohamae , Cynoglossus semilaevis ,
Chaet urichthys stigmatias , Chaet urichthys hexanema
Top pelagic feeders
　 　 Scomberomorus niphonius , Paralichthys olivaceus , Pagrosom us
major , Platycephal us i ndicus , S phyraena pinguis , S aurida elongata ,
Miichthys miiuy
Table 2 Parameter estimation for the group from the mass2balance model
of the Bohai Sea 3
Group Catches
(t·km - 2)
Biomass
(t·km - 2)
P/ B
(yr)
Q/ B
(yr)
EE
Microzooplankton - 4. 40 36. 0 186. 0 (0. 961)
Macrozooplankton 1. 40 2. 80 3. 00 12. 0 (0. 964)
Small mollusca 0. 78 (2. 76) 6. 85 27. 4 0. 950
Large mollusca 1. 50 0. 24 2. 00 7. 0 (0. 890)
Small crustacea 0. 20 (2. 01) 8. 00 30. 0 0. 950
Large crustacea 0. 20 0. 37 1. 50 11. 60 (0. 823)
Herbivorous feeders 0. 10 0. 56 3. 00 15. 0 (0. 903)
Small pelagic fish 0. 50 2. 14 2. 37 7. 9 (0. 927)
Demersal fish 0. 22 0. 62 2. 10 8. 7 (0. 808)
Benthic feeders 0. 10 0. 68 0. 80 4. 6 (0. 902)
Top pelagic feeders 0. 15 0. 59 0. 46 4. 1 (0. 553)
Phytoplankton - 15. 70 71. 20 - (0. 457)
Detritus - 43. 00 - - (0. 386)3 Values in brackets were calculated by the Ecopath program and dashes
mean no entry.
of a model when running the ECOPA TH software. The
EE value should be between 0 and 1. Here , a value of
zero indicates that the group is not consumed by any
other groups in the system , nor is it exported. Con2
versely , a value near or equal to 1 indicates that the
group is being heavily preyed or fished , leaving no indi2
viduals to die of old age[2 ] . Part of the original biomass
data f rom the Bohai Sea trawling survey in 1982～1983
are considered too low , which leads to make no equilib2
rium of the model with the high value of EE. This re2
sults f rom the survey data mainly connected with com 2
Table 3 Diet matrix for interacting groups in the Bohai Sea ecopath model
Prey Predator
1 2 3 4 5 6 7 8 9 10 11
1. Microzooplankton 0. 10 0. 40 0. 35 0. 30 0. 40 - 0. 15 0. 30 - - -
2. Macrozooplankton - - 0. 05 0. 05 - 0. 10 - 0. 15 - - -
3. Small mollusca - - - 0. 30 0. 15 0. 40 - 0. 20 0. 35 0. 20 0. 20
4. Large mollusca - - - - - - - - - 0. 05 0. 05
5. Small crustacea - - 0. 05 0. 20 0. 05 0. 20 - 0. 25 0. 35 0. 40 -
6. Large crustacea - - - - - - - - - - 0. 05
7. Herbivorous feeders - - - - - - - - 0. 10 - 0. 15
8. Small pelagic fish - - - 0. 05 - 0. 10 - 0. 10 0. 15 0. 15 0. 35
9. Demersal fish - - - - - - - - - 0. 15 0. 15
10. Benthic feeders - - - - - - - - 0. 05 - 0. 05
11. Top pelagic feeders - - - - - - - - - - -
12. Phytoplankton 0. 60 0. 20 0. 15 - - 0. 10 0. 30 - - - -
13. Detritus 0. 30 0. 40 0. 40 0. 10 0. 40 0. 10 0. 55 - - 0. 05 -
Total 1. 00 1. 00 1. 00 1. 00 1. 00 1. 00 1. 00 1. 00 1. 00 1. 00 1. 00
mercial species f rom bottom trawling , but the function
groups in the model cover more living marine species.
According to the result obtained by different resource
assessment methods[8 ] ,biomass value estimated by bot2
tom trawling survey is much lower than one from other
stock assessment methods. It is necessary to modify
thebiomass data to equilibrate the model. The biomass
of small pelagic fish group in the model is estimated to
2. 14 t·km - 2 instead of 1. 2 t·km - 2 in the Bohai Sea
survey. The biomass of benthic fish group is set to 0. 68
t·km - 2 instead of 0. 32 t·km - 2 in the survey.
4 　Discussion
A flow chart showing trophic interactions and ener2
gy flow in the Bohai Sea is seen in Fig. 2. It presents
the estimated trophic level of the 13 functional groups ,
the biomass and production , and the relative amounts of
energy that flow in and out of each box. The energy
834 应 　用 　生 　态 　学 　报 　　　　　　　　　　　　　　　　　　　11 卷
flow to detritus , respiration and catch are also seen in
the chart . The chart shows the two food paths , plank2
ton path and benthic community path. That is the food
web characteristic in the Bohai Sea ecosystem. The
model explores a matrix of direct and indirect impact of
competition and predation on species in the Bohai Sea
( Fig. 3) , which assesses how an increase in the biomass
of one group affects the biomass of other groups. The
figure shows the relative impacts but to be comparable
between groups. It can also give some insight into the
stability of the ecosystem in terms of its ability to with2
stand changes. The groups of lower trophic level impact
st rong to the Bohai Sea ecosystem. The great fishing ef2 fort in the sea leads to the decrease of high value livingmarine resources , which can be seen by the negative im2pacts to the ecosystem from fishery.The model estimated the biomass density of thespecies commercially utilized is 12. 33 t·km - 2 and thedensity for all fish species only 4. 4 t·km - 2 in the BohaiSea. We conclude that the total biomass of commerciallyfishing species in the sea is 950 thousand tons and 338thousand tons are fish species in the value. The densityin the Ecopath model is relatively lower compared withthe density in other ecosystem , such as Caribbean coralreef ecosystem and the Southern B. C. shelf model , butit is higher than the result published by the papers on
Fig. 2 Flow chart of trophic interactions in the Bohai Sea ecopath model.
All flows are in t·km - 2yr - 1. The size of each box is roughly proportional to the biomass therein (B :Biomass , P : Production) .
the Bohai Sea. Considering the weakness of other assess
methods depended mainly on the trawling data , the pa2
rameter estimation and energy flow from the Bohai Sea
ecosystem model ( 1982 ～ 1983 ) could be reasonable
even though they are only a preliminary assessment on
the ecosystem.
It is the first Ecopath model in the sea , so some
problems concerned with the input data have to be taken
into account in future Ecopath model. Firstly the func2
tion group should be split further to make more precise
input parameters of P/ B and Q/ B for each box. Second2
ly the diet data for some species is needed to be study
further to let diet consumption matrix be more reason2
able. Thirdly , it is better to consider the habitat for dif2
9343 期 　　　　　　　　　　　　　　　　　　仝 　龄等 :渤海生态通道模型初探 　　　　　　　　　
Fig. 3 Mixed trophic showing mix trophic impacts for the each groups in the Bohai Sea ecosystem.
Increasing the abundance of species on the Y2axis has positive (black bar) , negative (grey bar) or no effect on species listed on the X2axis.
ferent species in the Ecopath model.
Acknowledgements
We are grateful for the help from the Fisheries
Centre , University of British Columbia , in where a lot
of suggestion and encourage coming from the faculty and
the graduate students , specially to Prof . Tony J . Pitch2
er , Thomas A. Okey and Johanne Dalsgaard.
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of Aquatic Ecosystems. ICLARM , Conf . Proc. 26 :300～306
17 　Walters CJ , Christensen V and Pauly D. 1997. Structuring dynamic
model of exploited ecosystems from trophic mass2balance assessments.
Rev Fish Biol Fish ,7 :139～192
18 　Yang J2M , Yang W et al . 1990. The fish species biomass assessment
in the Bohai Sea. Acta Oceanol S in ,12 (3) :359～365
Author introduction 　Tong Ling ,male ,born in 1953 ,associate re2
search professor , who is involved recently in the studies on marine
fishery assessment model and ecosystem trophic dynamics model2
ing. 16 papers are published. E2mail :ysfri @public. qd. sd. cn
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