Ecosystem modelling in the western North Pacific from1994 to 2013 using Ecopath with Ecosim (EwE): somepreliminary results
HIROTO MURASE1, TSUTOMU TAMURA2, TAKASHI HAKAMADA2, SHINGO WATARI3, MAKOTO OKAZAKI3,
HIDETADA KIYOFUJI4 SHIROH YONEZAKI1 AND TOSHIHIDE KITAKADO5
1
National Research Institute of Far Seas Fisheries (Yokohama Laboratory), Fisheries Research Agency(FRA), 2-12-4 Fukuura, Kanazawa, Yokohama, Kanagawa 236-8648, Japan
2
The Institute of Cetacean Research, 4-5, Toyomi-cho, Chuo-ku, Tokyo 104-0055, Japan
3
National Research Institute of Fisheries Science, Fisheries Research Agency (FRA), 2-12-4 Fukuura,
Kanazawa, Yokohama, Kanagawa 236-8648, Japan
4
National Research Institute of Far Seas Fisheries (Shimizu Laboratory), Fisheries Research Agency (FRA),
5-7-1 Orido, Shimizu-ku, Shizuoka-shi, Shizuoka-ken 424-8633, Japan
5
Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo 108-8477, Japan

ABSTRACT
Marine ecosystem of the western North Pacific mainly focusing of top predators and forage fish is modelled as a part ofexercises under JARPNII using the ecosystem modelling framework, “Ecopath with Ecosim (EwE)”. Firstly, Ecopath in2013 is constructed as available data for the modelling is relatively rich. Ecopath in 1994 is then constructed based on themodel in 2013. Finally, Ecosim is constructed based on Ecopath in 1994 using available time series data from 1994 to 2013.
Regime of the period is relative stable in comparison with previous periods. A series of pre-balance diagnostics, “PREBAL”(Link, 2010) is conducted for both the 2013 and 1994 models to evaluate the initial satanic energy budget of Ecopath. An
ecosystem network analysis indicator, mixed trophic impact (MTI) is used to assess the positive or negative effect ofchanges in the biomass of a species/group on the biomass of the other species/groups in the steady state ecosystem. Orderof Trophic level (TL) of baleen whales is as follows (from high to low): common minke (4.1), Bryde’s (3.9), sei (3.7),
humpback (3.5), fin (3.3) and blue (3.2) whales. These species are in intermediate TL in the ecosystem. MTIs suggested
that changes in biomass of forage fish impact most of species/groups from low to high trophic levels. Baleen whales impact
forage fish negatively but the magnitude is weak. The Ecosim model with forced biomass time series of 4 forage fish
species (Japanese sardine and anchovy, and chub and spotted mackerels) having 10 predator and prey search blocks attains
the lowest AIC. Estimated time series of biomasses and total mortality by using the model are reasonably fitted to input
time series data especially for cetaceans targeted by JARPNII. The result might indicate strong linkage between cetaceans
and forage fish. Overall results appear to be reasonable but it is still preliminary largely because of incompleteness of input
data. The followings are points to be improved in the further excises: (1) consistency of spatial resolution of input data, (2)development of regional models within our EwE area, (3) collection of diet composition data in regular interval, (4)resolution and quality of data on non-commercial and lower trophic level species and (5) evaluation of the sensitivity of
Ecopath models to input data.

INTRODUCTION
The western North Pacific around Japan serves as an important fisheries ground for various species (Yatsu
et al., 2013). The Oyashio (a subarctic western boundary current with cold, low-salinity water) influences
the northern part while the Kuroshio (the subtropical western boundary current with warm high-salinity
water) influences the southern part (Fig. 1). The area between the Oyashio and the Kuroshio is called theKuroshio-Oyashio transition (inter-frontal) zone (area). The zone is also called as the subarctic-subtropicaltransition zone. Small pelagic fish such as Japanese sardine, Japanese anchovy, chub and spotted mackerels
and Pacific saury play important role in the ecosystem of the western North Pacific as they transfer energy
from lower to higher trophic levels. In addition, they are important target of commercial fisheries. Such an
ecosystem can be termed as “wasp-waist ecosystem” where many species exist at the top and the bottom
but a few dominant species (mostly small pelagic fishes) occupied the middle (analogous to body shape of
wasp in terms of number of species in an ecosystem) (Bakun, 2006; Cury et al., 2000). Small pelagic fish
also called as forage fish and their roles in marine ecosystems is actively studied in recent years by using
whole ecosystem models such as Ecopath with Ecosim (EwE) (Christensen and Walters, 2004) in recent
years (Pikitch et al., 2012; Pikitch et al., 2014). The Working Group on Ecosystem Modelling (EM) of the
Scientific Committee of the International Whaling Commission (IWC/SC) reviewed the related work withfocus on relationship between forage fish and whales (IWC, 2014). The Working Group recognized theecosystem models used in the studies to date were useful for their broad-scale strategic conclusions, butwere not suitable guides for short-term tactical management decisions.

1Spawning area of Japanese sardine and anchovy in the western North Pacific is located in the
coastal area of southern part of Japan where the influence of Kuroshio is strong. They are mainly distributedin the coastal area but it is well documented that they expand their distribution area to as far as 180°
longitude when the stocks are abundant (Giannoulaki et al., 2014). They are transported from the spawningarea to the Kuroshio-Oyashio transition zone by the Kuroshio and its extension. The transition zone serves
as their feeding ground but they also subject to predation by top predators including whales. They thenreturn to the spawning area. Chub and spotted mackerels and Pacific saury have same kind of migration
patterns. Spatial heterogeneity has to be considered when ecosystem models targeting on forage fish in thisarea are constructed because they utilize large area as their habitat.
These forage fish species showed drastic fluctuation and quasi-decadal species alterations socalled species replacement or biological regime shift from 1956 to 2012 (Fig. 2). Notably, rapid increase
and decrease in abundance of Japanese sardine was observed in 1980’s and the magnitude of the change
was an order of magnitude larger than previous and subsequent periods of 1980’s.The study group offisheries and ecosystem responses to recent regime shift under PICES defined regime shift as “a relative
rapid change from one decadal-scale period of a persistent state to another decadal-scale period of persistentstate” (King, 2005). Climate indices such as the Pacific Decadal Oscillation (PDO) indicated that significant
climatic regime shifts were occurred around 1976, 1989 and 1998 in recent decades (Overland et al., 2008).
No assessment on the regime after 1998 has been available. It was indicated that the species replacement
was related to the climate regime shift (Takasuka et al., 2008; Tian et al., 2004; Yatsu et al., 2008). Simple
interpretation of interaction between climatic and biological regime shifts was provided based on spawningtemperature optima theory among forage fish (Takasuka et al., 2008) but the exact mechanism is yet to be
determined. These studies focused on interaction among forage fish, their prey and climate, and interaction
between predators and forage fish has not been considered fully although changes in prey compositions of
top predators in response to the species replacement have been documented (Kasamatsu and Tanaka, 1992;
Ohizumi et al., 2000; Yonezaki et al., 2015b).
Ecosystem modelling in the western North Pacific using EwE was attempted as a part ofexercises under “the second phase of the Japanese Whale Research Program under Special Permit in the
North Pacific (JARPN II)” (Mori et al., 2009) and it was reviewed in the “Expert Workshop to review theongoing JARPN II Programme” held by IWC/SC in 2009 (IWC, 2010). The Panel provided a number of
constructive suggestions to improve the modelling work (Table 1).
In this paper, some preliminary results of EwE modelling in the western North Pacific arepresented. We mainly focus on interaction between forage fish and their predators including target speciesof JARPNII (common minke, sei, Bryde’s and sperm whales). Firstly, Ecopath in 2013 is constructed asavailable data for the modelling is relative rich. Ecopath in 1994 is then constructed based on the model in
2013. Finally, Ecosim is constructed based on Ecopath in 1994 using available time series data from 1994
to 2013. Initially, we intended to construct Ecopath in 1980’s when abundance of Japanese sardine wasenormously high to capture ecosystem regime shift since then. However, it was proved that such an excise
was difficult at this stage because of lack of basic input parameters. Instead, we focus on the period (19942013) when the regime appears to be stable but changes in biomass of forage fish are still observed (Fig.
3). The suggestions provided by the Panel is considered fully in the present model (Table 1).
MATERIALS AND METHODSIn this modelling exercise, the western North Pacific is divided into 3 geographical blocks consideringbottom topography and oceanography: coastal Oyashio (OYC), coastal Kuroshio (KC) and offshore (OF)(Fig. 1). OYC is mainly under the influence of Oyashio while KC is under the influence of Kuroshio. OYC
and KC is corresponding to the areas where offshore bottom trawl fisheries are conducted and the catch
statistics are available. OF is corresponding to the Oyashio-Kuroshio transition zone. Species/groups
considered in the modelling are summarized in Table 2. It is assumed that some species are endemic to a
block (e.g. bottom fish) while migrating species are distributed 2 or 3 blocks. The blocks are connected bythese migrating species. Similar approach attempted in the Mediterranean Sea (Piroddi et al., 2015) is
adopted in the study.
EwE mainly consists of two modules: Ecopath and Ecosim. Ecopath deals with mass balance
modelling while Ecosim deals with time-dynamic modelling based on the result of Ecopath. Initially, a2

mass balance model in 2013 is constructed by using Ecopath. Ecopath has two basic equations. The firstequation describes production term which ensure mass balance in the ecosystem:

Pi  Yi  M 2i  Bi  Ei  BAi  Pi  1  EEi (1)where Pi is the total production rate of species i, Yi is the total fishery catch rate of i, M2i is the total predation
rate for i, Bi it the biomass of i, Ei is the net migration rate (emigration and immigration) of i, BAi is thebiomass accumulation rate for i and Pi(1-EEi) is the other mortality rate for i (M0i). EEi is ecotrophic
efficiency of i which can be described as the proportion of the production utilized in the ecosystem. M2ilinks between predator j of i:n

M 2i   Q j DC ji
j 1

(2)
where n is a total number of j feeding on i, Qj is the total consumption rate for j and DCji is proportion i as
the diet of j. Equation (1) can be re-expressed as:
n
P
Q
Bi     EEi   B j     DC ji  Yi  Ei  BAi  0 B i B jj 1(3)
where (P/B)i is the ratio of production and biomass ratio and (Q/B)j is the ratio of consumption and biomass.
Production and biomass ratio (P/B) is generally corresponding to total mortality rate, Z (fishing mortality
rate [F] plus natural mortality rare [M]) (Allen, 1971). If either 3 parameters from following 4 parameterare supplied along with DC to Ecopath, rest of a parameter is estimated by Ecopath: B, P/B, Q/B and EE.
The second basic equation ensures balances within each species/groups:

Qi  Pi  Ri  GSi  Qi
(4)where Ri is respiration for i, GSi is proportion of food that is not assimilated for i. Wet weight (t) is used as
currency in the modelling. Another mass balance model in 1994 is then constructed based on the 2013
model. Basic input parameters for the 2013 and 1994 models are summarized in Table 3 and 4 Diet
compositions are summarized in Table 5. Same diet compositions are assumed in both 2013 and 1994
models. Fishery landings used in the models are summarized in Table 6. No fleet type is considered.
Proportion of unassimilated consumption is set as 0.2 for all species/groups. No detritus import is assumed.
Details of input parameters are described in Appendix 1. A series of pre-balance diagnostics, “PREBAL”(Link, 2010) is conducted for both the 2013 and 1994 models to evaluate the initial satanic energy budgetof Ecopath. A ecosystem network analysis indicator, mixed trophic impact (MTI) (Ulanowicz and Puccia,
1990), calculated by Ecopath based on the balanced models is used to assess the positive or negative effectof changes in the biomass of a species/group on the biomass of the other species/groups in the steady stateecosystem. Both direct and indirect effect are taken account by the MTI. The MTI for species/groups iscalculated by constructing an n by n matrix where the ith and jth elements representing the interaction
between the impacting group i and the impacted group j:

MTI i , j  DCi , j  FC j ,i(5)where DCi,j is the diet composition term expressing how much j contributes to the diet of i, and FCj,i is ahost composition term giving the proportion of the predation on j that is due to i as a predator.
Various times series from 1994 to 2013 are fitted to the balanced Ecpath model in 1994 by using
Ecosim. Biomass dynamics are expressed through a series of coupled differential equations in Ecosim andthe equations are derived from the first basic equation of Ecopath:3

dBi
 g i  Q ji   Qij  I i  M 0i  Fi  ei Bi
dt
j
j
(6)
where dBi/dt is the biomass growth rate during the time interval dt of i, gi is the net growth efficiency(production/consumption ratio), Fi is fishing mortality rate for i, ei is emigration rate for i, Ii is immigration
rate for i, (hence ei·Bi- Ii is the net migration rate). The first summation is the first expressing the total
consumption by i, and the second is the predation by all predators on i. Consumption rate, Qji, in Ecosim isbased on the foraging arena theory (Ahrens et al., 2012) and expressed as:

Qij 

aij  vij  Bi  Pj  Ti  T j  S ij  M ij / D jvij  vij  Ti M ij  aij  M ij  Pj  S ij  T j / D j(7)

where, aij is the effective search rate for predator i feeding on prey j, vij is base vulnerability expressing therate with which prey move between being vulnerable and not vulnerable, Bi is biomass of prey, Pj is biomassof j, Ti is prey relative feeding time, Tj is predator relative feeding time, Sij is user-defined seasonal or longterm forcing effects, Mij mediation forcing effects, and Dj represents effects of handling time of predator.
Parameters v, T, S, M and D can be set by modellers but it is assumed that v has the strongest effect on
biomass dynamics in Ecosim. High value of v indicates top-down control while the low value indicatesbottom-up control. Direct assessment of vulnerability based on field observation is difficult for most of
species. Instead, it can be estimated through time series fitting implemented in Ecosim. Goodness of fit totime series is measured by a weighted sum of squared deviations (SS) of log biomasses from log predictedbiomasses, scaled in the case of relative abundance data by the maximum likelihood estimate of the relative
abundance scaling factor q in the equation y=qB (y=relative abundance, B=absolute abundance). In thispaper, biomass dynamics from 1994 to 2013 (20 years) are modelled based on Ecopath in 1994. A total of
29 time series data are used in the analysis (Table 7). Equal weight is assigned to all time series. Proceduresfor the time series fitting are as follows. Firstly, sensitives of SS to v by predator and prey blocks are
determined by changing each one slightly (1%) then rerunning the model to see how much SS is changed.
Secondly, v estimates that give better fits to the time series data (lower SS) with vulnerabilities blocks issearched. Number of predator and prey blocks which are used to estimate v are increased from 5 until thesmallest AIC (Akaike information criteria). Default value of v is set as 2. In this exercise, effect of changes
in biomass of small forage fish (Japanese sardine, Japanese anchovy and, chub and spotted mackerel) on
changes in biomass of top predators is mainly investigated. The model attained the smallest AIC isconsidered as the best model.
RESULTS AND DISCUSSION
Estimated basic parameters for Ecopath in 2013 and 1994 are summarized in Tables 8 and 9. The results ofPREBAL are summarized in Appendices 2 and 3. The balanced models are considered to be reasonable
based on the results of PREBAL although some parameters might need to be revisited in the future forfurther check. The food webs in 2013 and 1994 estimated by Ecopath are shown in Figs. 4 and 5. Baird’s
beaked whale attains the highest trophic level (TL) followed by sperm and pilot whales, mesopelagic sharks
and tunas in both 2013 and 1994. Order of TL of baleen whales is as follows (from high to low): common
minke (4.1), Bryde’s (3.9), sei (3.7), humpback (3.5), fin (3.3) and blue (3.2) whales. These species are inintermediate TL. MTIs in 2014 and 1993 are shown in Figs. 6 and 7. MTIs suggested that changes inbiomass of forage fish impact most of species/groups from low to high trophic levels. Baleen whales impact
forage fish negatively but the magnitude is weak. Overall, outputs from Ecopath between 2013 and 1994
are similar. The results are not surprising as both years are under similar regime.
Results of time series fitting from 1994 to 2013 are summarized in Table 10. The model withforced biomass time series of 4 forage fish species (Japanese sardine and anchovy, and chub and spottedmackerels) having 10 predator and prey search blocks attain the lowest AIC (model number 19 in Table
10). Estimated vulnerability parameters for the selected model are summarized in Table 11. Strong topdown controls are expected for the following predator/prey in the modelled period: blue shark/Japanese
anchovy, Japanese anchovy/zooplankton (OF), chub mackerel (all)/Japanese anchovy (all), chub mackerel(all)/krill (OF), chub mackerel (all)/zooplankton (OF), spotted mackerel (all)/krill (OF) and spotted4mackerel (all)/zooplankton (OF). The vulnerability parameters for the rest of predator and prey blocks are
estimated as 2 and this suggested intermediate interactions between predator and prey. Estimated time seriesof biomass, total mortality and catch are shown in Figs. 8-10. Estimated time series for the model without
forcing on biomass time series of 4 forage fish species (model number 7 in Table 1) are also shown in the
figures for comparison. Reasonable results of time series fitting for biomass and total mortality are obtained
especially for cetaceans if the biomass time series of forage fish are forced. The result might indicate strong
linkage between cetaceans and forage fish. There are discrepancies for catch data even if the biomass timeseries of forage fish are forced.
We consider that results obtained by this exercises are reasonable but it is still preliminary largely
because of incompleteness of input data. Following are points to be improved:(1) Consistency of spatial resolution of input data
Spatial resolutions of input data are varied from data to data. Some data are recorded within our EwE area
(e.g. JAPRNII) but some are not. For instance, biomass of highly migrating fish (e.g. tunas) are estimatedin much wider area than our EwE area for the purpose of the stock assessment (e.g. the entire Pacific). It is
assumed that biomass density is same for these two areas. However, the assumption might not be valid
because spatial heterogeneity of spatial distribution of target species is expected. Such inconsistencies ofspatial resolutions are also occurred within our EwE area. Only a point estimate of biomass is available formost of species. Spatial estimation of biomass of some of the species in our EwE area are undergoing byusing either statistical models (e.g. generalized additive model, GAM) (Murase et al., 2016: SC/F16/JR7)
or spatial ecosystem models such as individual based ecosystem models (Okunishi et al., 2012) andSEAPODYM (Lehodey et al., 2011). Integration or coupling with these models could be one of the future
solutions along with preparation of appropriate raw data.
(2) Development of regional models within our EwE area
Regional details are largely overlooked in our EwE model because it covers quite large area. The Ecopath
model developed in the southern part of the OYC block (Yonezaki et al., 2015a) acts as a good source ofbasic input of our EwE. Development of regional EwE models especially in the coastal area of Japan (e.g.
northern part of OYC and KC blocks) will be helpful to improve our EwE model.
(3) Collection of diet composition data in regular interval
Some of the diet composition data used in our model are old qualitative data and/or obtained outside of themodelled area. Collection of diet composition data especially for top predators in the area in regular intervalmust be conducted to improve the model performance. It is especially true if the aim of the modelling is toinvestigate mechanism of regime shift in the area.
(4) Resolution and quality of data on non-commercial and lower trophic level species
Resolution (in terms of number of species/groups) and quality of data on non-commercial and lower trophic
level species are not satisfactory in our model. Effort on assembling existent data and collection of new
data (if necessary) should be made further.
(5) Evaluation of the sensitivity of Ecopath models to input data
Although the initial satanic energy budget of Ecopath was evaluated in this paper applying a series of prebalance diagnostics, sensitivity of Ecopath models to input data (Essington, 2007) should also be evaluatedin the future excises.
ACKNOWLEDGEMENT
Data used in the paper were assemble in collaboration with following scientists: Dr. Yu Kanaji at National
Research Institute of Far Seas Fisheries (Yokohama Laboratory), Drs. Mikihiko Kai, Seiji Ohshimo,
Kazuhiro Oshima and Yasuko Senba at National Research Institute of Far Seas Fisheries (Shimizu
Laboratory), Drs. Kazuya Nashida, Kyohei Segawa and Akinori Takasuka at National Research Instituteof Fisheries Science, Dr. Toshikazu Yano at Tohoku National Fisheries Research Institute and Dr. Takahiko
Kameda at Sekai National Fisheries Research Institute. The authors express their thanks the collaborators.
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Table 1. Suggestions by the Panel of the expert workshop to review the ongoing JARPNII programme (IWC, 2010)
to improve Ecopath and Ecosim modelling in the western North Pacific (left column). Improvement in themodelling in this paper based on these suggestions are also listed (right column).
Suggestion
Considerably more resources must be allocated to themodelling work – without this, the likelihood that theobjective of the programme will be reached in a reasonable
timeframe will be minimal. The models developed should be
used to identify the areas of uncertainty with the greatest
impact on model outputs of relevance to management, andhence to guide the prioritisation of future data collection andthe associated sample size/sampling design.
A wider range of models needs to be considered if theobjectives of the programme are to be met. Further work
should aim towards fitting dynamic models to time series ofdata, especially abundance indices.
The area covered by JARPN II is not spatially homogeneous,and serious consideration should be given to developing
separate models for three regions distinguished by theinshore or shelf region, the sub-Arctic oceanic region of the
Oyashio current and the sub-tropical region of the Oyashio
and Kuroshio transition zone.
There is a need to take much wider account of uncertainty at
all stages of the modelling process, including that associatedwith the prey consumption rates of whales
The importance, ultimately, of developing models which
incorporate natural variability in dynamic processes wasemphasised, although it was recognised that this might not
be possible for certain ecosystem modelling ‘packages’. This
is in addition to taking account of uncertainty in model
structure and parameter values. The complexity of
ecosystems and the difficulty of modelling species
interactions adequately might mean that management actions
based on such models are more likely to induce unexpected
instabilities than current single-species based approaches;
this suggests a more cautious approach will be needed on thepart of decision makers.
It is important to concentrate first on improving the Ecopath
component of this EwE analysis before moving on to thenext step of extending the modelling effort from a static to a
dynamic model such as Ecosim.
The species included in the Ecopath analysis should be
reviewed giving attention to Ecopath models developed forother regions; in particular the inclusion of gelatinous
zooplankton should be considered. Furthermore the values ofthe parameters of this Ecopath analysis should be comparedwith values for those others, with attention directed towards
any instances of major discrepancies.
The need to rebalance the Ecopath model. Alternative
approaches to doing so should be considered. For example,
rather than use values for some parameters drawn from otherregions, placing a bound on some relationship (e.g. P/C<0.6)
may lead to an improved result overall.
Further analyses must take full account of the uncertainties
associated with model inputs e.g. using Ecoranger

8

Improvement in response to the suggestion
Collaboration with specialists in other disciplines (e.g.
oceanography, pelagic fish and highly migratory fish [sharks
and tunas]) has been strengthened for EwE modelling.

Time series data from 1994 to 2013 is fitted in Ecosim toestimate vulnerability parameters which is one of importantparameters in the model
A quasi sub-model structure is established in EwE
considering bottom topography and oceanography themodelled area.

Uncertainty is not addressed fully in EwE althoughvulnerability parameters is estimated in Ecosim.
A climate index, the Pacific the Pacific Decadal Oscillation(PDO) index, is initially considered whether it can be used
as forcing function in Ecosim. However, it is not consideredin actual modelling because it appear that influence of PDO
on biomass dynamics in the modelling period (1994-2013) is
not strong. But it is still on the to-do list in the further
modelling especially if the modelling period is expanded tothe past.

A series of pre-balance diagnostics, “PREBAL” (Link,
2010) is conducted for both the 2013 and 1994 models toevaluate the initial satanic energy budget of Ecopath before
Ecosim modelling is conducted.
Because EwE mainly focuses on offshore instead of nearshore area, it appears that gelatinous zooplankton is not key
species in the modeled area. In addition, such data scarce sofar. Presented EwE modelling mainly focus on interaction
between forage fish and their predators and the number of
predators in the model is increased from the previous one.
Values of basic parameters are compared with other models
qualitatively.
A series of pre-balance diagnostics, “PREBAL” (Link,
2010) is conducted for both the 2013 and 1994 models toevaluate the initial satanic energy budget of Ecopath before
Ecosim modelling is conducted.
Ecoranger is not used in the modelling as the development islittle so far.

Table 2. Species/groups considered in Ecopath and Ecosim in the western North Pacific in 2013 and 1994.
Allocations to the 3 geographic blocks (OYC, KC and OF) are also shown. Migrating species are allowed to be
distributed in 2 or 3 blocks.
Allocation to the geographical blocks
Category

Baleen whales

Toothed whales

Seabirds
Elasmobranch
Tunas
BillfishMiscellaneous piscivores

Small pelagic fish

Bottom fish

Mesopelagic fish

SquidsBenthos
Krill

Miscellaneous zooplankton

Phytoplankton

Detritus

CoastalOyashio(OYC)

Species/group

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

Blue whale (OYC, OF)
Fin whale (OYC, OF)
Sei whale (OYC, OF)
Bryde's whale (OYC, OF)
Common minke whale (OYC, OF)
Humpback whale (OYC, OF)
Sperm whale (all)Killer whale (all)Large dolphins (all)Small dolphins (all)Dall's porpoise (OYC, OF)
Pilot whale (all)Baird’s beaked whale (OYC)
Beaked whales (all)Seabirds (all)Blue shark (all)Mesopelagic sharks (OYC)
Tunas (all)Skipjack (all)Swordfish (all)Miscellaneous piscivores (all)Japanese sardine (all)Japanese anchovy (all)Pacific saury (all)Chub mackerel (all)Spotted mackerel (all)Righteye flounders (OYC)
Alaska pollock (OYC)
Miscellaneous bottom fish (OYC)
Righteye flounders (KC)
Seabreams (KC)
Miscellaneous bottom fish (KC)
Mesopelagic fish (OYC)
Mesopelagic fish (KC)
Mesopelagic fish (OF)Surface squids (all)Mesopelagic squids (all)Benthos (OYC)
Benthos (KC)
Krill (OYC)
Krill (OF)
Zooplankton (OYC)
Zooplankton (KC)
Zooplankton (OF)Phytoplankton (OYC)
Phytoplankton (KC)
Phytoplankton (OF)
Detritus (OYC)
Detritus (KC)
Detritus (OF)9

CoastalKuroshio(KC)

Offshore(OF)OYC/OFAll
blocks

x
x
x
x
x
x
x
x
x
x
x
X
x
x
x
X
x
x
x
x
x
x
x
x
x
X
X
X
x
x
x
X
x
x
x
x
X
x
X
x
X
x
x
X
x
x
X
x
X

Table 3. Basic input parameters for Ecopath in the western North Pacific in 2013. OYC: coastal Oyasio block, KC:coastal Kuroshio block, OF: offshore block, B in habitat: biomass (t/km2) in distributed blocks, P/B:
production/biomass ratio, Q/B: consumption/biomass ratio EE: ecotrophic efficiency and P/Q:
production/consumption ratio.
Species/group
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

Blue whale (OYC, OF)
Fin whale (OYC, OF)
Sei whale (OYC, OF)
Bryde's whale (OYC, OF)
Common minke whale (OYC, OF)
Humpback whale (OYC, OF)
Sperm whale (OYC, OF)
Killer whale (all)Large dolphins (all)Small dolphins (all)Dall's porpoise (OYC, OF)
Pilot whales (all)Baird's beaked whale (OYC)
Beaked whales (all)Seabirds (all)Blue shark (all)Mesopelagic sharks (OYC)
Tunas (all)Skipjack (all)Swordfish (all)Miscellaneous piscivores (all)Japanese sardine (all)Japanese anchovy (all)Pacific saury (all)Chub mackerel (all)Spotted mackerel (all)Righteye flounders (OYC)
Alaska pollock (OYC)
Miscellaneous bottom fish (OYC)
Righteye flounders (KC)
Seabreams (KC)
Miscellaneous bottom fish (KC)
Mesopelagic fish (OYC)
Mesopelagic fish (KC)
Mesopelagic fish (OF)Surface squids (all)Mesopelagic squids (all)Benthos (OYC)
Benthos (KC)
Krill (OYC)
Krill (OF)
Zooplankton (OYC)
Zooplankton (KC)
Zooplankton (OF)Phytoplankton (OYC)
Phytoplankton (KC)
Phytoplankton (OF)
Detritus (OYC)
Detritus (KC)
Detritus (OF)

Habitatarea(fraction)
0.950
0.950
0.950
0.950
0.950
0.950
0.950
1.000
1.000
1.000
1.000
0.950
0.050
1.000
1.000
1.000
0.050
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
0.050
0.050
0.050
0.050
0.050
0.050
0.050
0.050
0.900
1.000
1.000
0.050
0.050
0.050
0.900
0.050
0.050
0.900
0.050
0.050
0.900
0.050
0.050
0.900

B in
habitat
0.022
0.053
0.034
0.035
0.006
0.009
0.160
0.002
0.003
0.025
0.002
0.002
0.049
0.004
0.003
0.089
0.107
0.036
0.027
0.001
0.446
1.156
0.851
1.240
1.009
0.946
4.889
14.138
0.001
0.003
0.025

64.534114.489
23.39229.7308.067
11.643
13.55510.0129.036
47.91130.18447.499

10

P/B

Q/B

EE

0.040
0.052
0.099
0.087
0.120
0.072
0.061
0.100
0.120
0.143
0.138
0.147
0.105
0.100
0.120
0.464
0.330
0.326
0.458
0.490
2.250
0.517
2.180
1.523
0.513
0.486
0.446
0.840
0.393
0.446
0.490
0.346
1.500
1.500
1.500
2.555
2.979
3.030
2.530
2.555
2.555
23.16023.16023.160153.776
128.274
153.776

4.220
4.548
4.384
7.372
4.581
4.634
8.696
4.381
7.778
10.777
11.49214.2874.872
7.855
36.667
1.325
2.900
6.754
16.200
2.500
7.700

0.950

P/Q

0.200
0.200
0.200
0.200
0.200
2.893
2.212
3.182
2.893
2.450
2.832

7.300
13.641
10.1028.430
12.04512.04545.35045.35045.350

0.900
0.900
0.900
0.950
0.938
0.915

0.250
0.250
0.250

Table 4. Basic input parameters for Ecopath in the western North Pacific in 1994. OYC: coastal Oyasio block, KC:coastal Kuroshio block, OF: offshore block, B in habitat: biomass (t/km2) in distributed blocks, P/B:
production/biomass ratio, Q/B: consumption/biomass ratio EE: ecotrophic efficiency and P/Q:
production/consumption ratio. Parameters changed from the 2013 model are in italic with underline.
Species/group
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

Blue whale (OYC, OF)
Fin whale (OYC, OF)
Sei whale (OYC, OF)
Bryde's whale (OYC, OF)
Common minke whale (OYC, OF)
Humpback whale (OYC, OF)
Sperm whale (OYC, OF)
Killer whale (all)Large dolphins (all)Small dolphins (all)Dall's porpoise (OYC, OF)
Pilot whales (all)Baird's beaked whale (OYC)
Beaked whales (all)Seabirds (all)Blue shark (all)Mesopelagic sharks (OYC)
Tunas (all)Skipjack (all)Swordfish (all)Miscellaneous piscivores (all)Japanese sardine (all)Japanese anchovy (all)Pacific saury (all)Chub mackerel (all)Spotted mackerel (all)Righteye flounders (OYC)
Alaska pollock (OYC)
Miscellaneous bottom fish (OYC)
Righteye flounders (KC)
Seabreams (KC)
Miscellaneous bottom fish (KC)
Mesopelagic fish (OYC)
Mesopelagic fish (KC)
Mesopelagic fish (OF)Surface squids (all)Mesopelagic squids (all)Benthos (OYC)
Benthos (KC)
Krill (OYC)
Krill (OF)
Zooplankton (OYC)
Zooplankton (KC)
Zooplankton (OF)Phytoplankton (OYC)
Phytoplankton (KC)
Phytoplankton (OF)
Detritus (OYC)
Detritus (KC)
Detritus (OF)

Habitatarea(fraction)
0.950
0.950
0.950
0.950
0.950
0.950
0.950
1.000
1.000
1.000
1.000
0.950
0.050
1.000
1.000
1.000
0.050
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
0.050
0.050
0.050
0.050
0.050
0.050
0.050
0.050
0.900
1.000
1.000
0.050
0.050
0.050
0.900
0.050
0.050
0.900
0.050
0.050
0.900
0.050
0.050
0.900

B in
habitat
0.022
0.053
0.024
0.038
0.006
0.009
0.136
0.002
0.003
0.025
0.002
0.002
0.049
0.004
0.003
0.077
0.107
0.051
0.037
0.001
1.276
0.920
0.851
0.494
0.494
0.946
4.889
14.138
0.001
0.003
0.025

64.534114.489
23.39223.4508.487
11.643
13.55510.0129.036
47.91130.18447.499

11

P/B

QB

EE

0.040
0.052
0.099
0.087
0.120
0.072
0.061
0.100
0.120
0.143
0.138
0.147
0.105
0.100
0.120
0.727
0.330
0.299
0.468
0.490
2.250
0.613
2.019
1.523
0.497
0.497
0.446
0.840
0.393
0.446
0.490
0.346
1.500
1.500
1.500
2.555
2.979
3.030
2.530
2.555
2.555
23.16023.16023.160153.776
128.274
153.776

4.220
4.548
4.384
7.372
4.581
4.634
8.696
4.381
7.778
10.777
11.49214.2874.872
7.855
36.667
1.325
2.900
6.754
16.200
2.500
7.700

0.950

P/Q

0.200
0.200
0.200
0.200
0.200
2.893
2.212
3.182
2.893
2.450
2.832

7.300
13.641
10.1028.430
12.04512.04545.35045.35045.350

0.900
0.900
0.900
0.950
0.938
0.915

0.250
0.250
0.250

Table 5. Diet compositions (DCs, expressed in proportions) for Ecopath in the western North Pacific in 2013 and1994. OYC: coastal Oyasio block, KC: coastal Kuroshio block, OF: offshore block
Sperm whale (OYC, OF)

4

5

6

7

8
0.001
0.001
0.001
0.001
0.001
0.001
0.001

Dall's porpoise (OYC, OF)

Humpback whale (OYC, OF)

3

Small dolphins (all)Common minke whale (OYC, OF)

2

Large dolphins (all)Bryde's whale (OYC, OF)

1

Killer whale (all)Sei whale (OYC, OF)Blue whale (OYC, OF)
Fin whale (OYC, OF)
Sei whale (OYC, OF)
Bryde's whale (OYC, OF)
Common minke whale (OYC, OF)
Humpback whale (OYC, OF)
Sperm whale (OYC, OF)
Killer whale (all)Large dolphins (all)Small dolphins (all)Dall's porpoise (OYC, OF)
Pilot whales (all)Baird's beaked whale (OYC)
Beaked whales (all)Seabirds (all)Blue shark (all)Mesopelagic sharks (OYC)
Tunas (all)Skipjack (all)Swordfish (all)Miscellaneous piscivores (all)Japanese sardine (all)Japanese anchovy (all)Pacific saury (all)Chub mackerel (all)Spotted mackerel (all)Righteye flounders (OYC)
Alaska pollock (OYC)
Miscellaneous bottom fish (OYC)
Righteye flounders (KC)
Seabreams (KC)
Miscellaneous bottom fish (KC)
Mesopelagic fish (OYC)
Mesopelagic fish (KC)
Mesopelagic fish (OF)Surface squids (all)Mesopelagic squids (all)Benthos (OYC)
Benthos (KC)
Krill (OYC)
Krill (OF)
Zooplankton (OYC)
Zooplankton (KC)
Zooplankton (OF)Phytoplankton (OYC)
Phytoplankton (KC)
Phytoplankton (OF)
Detritus (OYC)
Detritus (KC)
Detritus (OF)Fin whale (OYC, OF)

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

Blue whale (OYC, OF)

Prey/Predator

9

10

11

0.011
0.028
0.011
0.010
0.010
0.010
0.030
0.048
0.000
0.000
0.000
0.020
0.020
0.030
0.002
0.730
0.020
0.020

0.010
0.056
0.010
0.010
0.010

0.001
0.016
0.001
0.002
0.002

0.001
0.001
0.001
0.001
0.001
0.001

0.010
0.050
0.020
0.010
0.010

0.010
0.424
0.043
0.048
0.048

0.010
0.726
0.017
0.017

0.013
0.010
0.407
0.315
0.002
0.002

0.009

0.052
0.948

0.034
0.616
0.013

0.009
0.157
0.013

0.237

0.238

12

0.030
0.004

0.012
0.209

0.019
0.001
0.977

0.010
0.010
0.180
0.001
0.494

0.010
0.300
0.070
0.010
0.010

0.107
0.010

0.010

0.003

0.001
0.001
0.010
0.010
0.010
0.020
0.022
0.076
0.022
0.040
0.040
0.010
0.010
0.020

0.005
0.088

0.021
0.379
0.010

0.007

0.190

0.020
0.226

0.000
0.016
0.016
0.292
0.003
0.330
0.011
0.010

0.044
0.044
0.792
0.001
0.077

Table 5. (Continued)

Beaked whales (all)Seabirds (all)Blue shark (all)Mesopelagic sharks (OYC)

Tunas (all)Skipjack (all)Swordfish (all)Miscellaneous piscivores (all)Japanese sardine (all)Blue whale (OYC, OF)
Fin whale (OYC, OF)
Sei whale (OYC, OF)
Bryde's whale (OYC, OF)
Common minke whale (OYC, OF)
Humpback whale (OYC, OF)
Sperm whale (OYC, OF)
Killer whale (all)Large dolphins (all)Small dolphins (all)Dall's porpoise (OYC, OF)
Pilot whales (all)Baird's beaked whale (OYC)
Beaked whales (all)Seabirds (all)Blue shark (all)Mesopelagic sharks (OYC)
Tunas (all)Skipjack (all)Swordfish (all)Miscellaneous piscivores (all)Japanese sardine (all)Japanese anchovy (all)Pacific saury (all)Chub mackerel (all)Spotted mackerel (all)Righteye flounders (OYC)
Alaska pollock (OYC)
Miscellaneous bottom fish (OYC)
Righteye flounders (KC)
Seabreams (KC)
Miscellaneous bottom fish (KC)
Mesopelagic fish (OYC)
Mesopelagic fish (KC)
Mesopelagic fish (OF)Surface squids (all)Mesopelagic squids (all)Benthos (OYC)
Benthos (KC)
Krill (OYC)
Krill (OF)
Zooplankton (OYC)
Zooplankton (KC)
Zooplankton (OF)Phytoplankton (OYC)
Phytoplankton (KC)
Phytoplankton (OF)
Detritus (OYC)
Detritus (KC)
Detritus (OF)

Baird's beaked whale (OYC)

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

Pilot whales (all)Prey/Predator

12

13

14

15

16

17

18

19

20

21

22

0.079
0.010
0.040
0.010
0.020
0.020

0.100

0.000
0.005
0.005
0.090
0.001
0.620

0.956

0.001
0.043

0.008
0.010
0.070
0.067
0.010
0.010

0.005
0.010
0.371
0.010
0.010
0.010

0.017
0.017
0.299
0.001
0.335

0.001
0.001
0.026
0.001
0.535

0.004
0.072
0.004
0.004
0.072

0.001
0.019

0.074

0.000
0.009
0.009
0.158
0.001
0.699
0.025
0.025

13

0.001
0.007
0.001
0.001
0.001
0.139
0.039
0.503

0.011

0.044
0.167
0.080
0.006

0.002
0.001

0.001
0.001

0.000
0.013

0.001
0.001

0.242
0.010
0.139
0.090
0.090
0.090

0.077
0.010
0.104
0.070
0.070
0.070

0.001
0.010
0.126
0.100
0.100
0.100

0.005
0.005
0.020
0.010
0.005
0.005

0.007
0.007
0.121
0.001
0.184

0.009
0.009
0.158
0.001
0.302

0.003
0.003
0.050
0.001
0.412

0.016
0.016
0.284
0.001
0.315

0.001
0.007
0.001
0.001
0.006

0.003
0.056
0.003
0.003
0.053

0.002
0.038
0.002
0.002
0.037

0.008
0.150
0.008
0.008
0.142

0.002
0.004
0.025
0.025
0.447
0.025
0.025
0.447

Table 5. (Continued)

0.001
0.032

0.002
0.019
0.688

Mesopelagic fish (OYC)

0.001
0.013

Miscellaneous bottom fish (KC)

(all)

0.006

Seabreams (KC)

0.001
0.003
0.001
0.001
0.001
0.002
0.010
0.041

Righteye flounders (KC)

0.010
0.226

25

Miscellaneous bottom fish (OYC)

0.010
0.242

24

Alaska pollock (OYC)

Righteye flounders (OYC)
27

23

Spotted mackerel
26

Chub mackerel (all)Blue whale (OYC, OF)
Fin whale (OYC, OF)
Sei whale (OYC, OF)
Bryde's whale (OYC, OF)
Common minke whale (OYC, OF)
Humpback whale (OYC, OF)
Sperm whale (OYC, OF)
Killer whale (all)Large dolphins (all)Small dolphins (all)Dall's porpoise (OYC, OF)
Pilot whales (all)Baird's beaked whale (OYC)
Beaked whales (all)Seabirds (all)Blue shark (all)Mesopelagic sharks (OYC)
Tunas (all)Skipjack (all)Swordfish (all)Miscellaneous piscivores (all)Japanese sardine (all)Japanese anchovy (all)Pacific saury (all)Chub mackerel (all)Spotted mackerel (all)Righteye flounders (OYC)
Alaska pollock (OYC)
Miscellaneous bottom fish (OYC)
Righteye flounders (KC)
Seabreams (KC)
Miscellaneous bottom fish (KC)
Mesopelagic fish (OYC)
Mesopelagic fish (KC)
Mesopelagic fish (OF)Surface squids (all)Mesopelagic squids (all)Benthos (OYC)
Benthos (KC)
Krill (OYC)
Krill (OF)
Zooplankton (OYC)
Zooplankton (KC)
Zooplankton (OF)Phytoplankton (OYC)
Phytoplankton (KC)
Phytoplankton (OF)
Detritus (OYC)
Detritus (KC)
Detritus (OF)

Pacific saury (all)

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

Japanese anchovy (all)Prey/Predator

28

29

30

31

32

33

0.003
0.010
0.003
0.003
0.003
0.004
0.004
0.035

0.001
0.003
0.000
0.001
0.001

0.003
0.010
0.003
0.003
0.003

0.001
0.000
0.001

0.001
0.001
0.001

0.005

0.188

0.153
0.029

0.002
0.102
0.566

0.006

0.166

0.002
0.019

0.002
0.102
0.250

0.688
0.015
0.285
0.033
0.033
0.604
0.01
0.01
0.01

0.010
0.190
0.040
0.040
0.720

0.018
0.352
0.018
0.018
0.328

14

0.019
0.365
0.017
0.017
0.313

0.001

0.166

0.159

0.488

0.043

0.066

0.137

0.056

0.600

0.566
0.500
0.250

0.277

0.399

0.139

Table 5. (Continued)

Surface squids (all)Mesopelagic squids (all)Benthos (OYC)

Benthos (KC)

Krill (OYC)

Krill (OF)

Zooplankton (OYC)

Zooplankton (KC)

Zooplankton (OF)Blue whale (OYC, OF)
Fin whale (OYC, OF)
Sei whale (OYC, OF)
Bryde's whale (OYC, OF)
Common minke whale (OYC, OF)
Humpback whale (OYC, OF)
Sperm whale (OYC, OF)
Killer whale (all)Large dolphins (all)Small dolphins (all)Dall's porpoise (OYC, OF)
Pilot whales (all)Baird's beaked whale (OYC)
Beaked whales (all)Seabirds (all)Blue shark (all)Mesopelagic sharks (OYC)
Tunas (all)Skipjack (all)Swordfish (all)Miscellaneous piscivores (all)Japanese sardine (all)Japanese anchovy (all)Pacific saury (all)Chub mackerel (all)Spotted mackerel (all)Righteye flounders (OYC)
Alaska pollock (OYC)
Miscellaneous bottom fish (OYC)
Righteye flounders (KC)
Seabreams (KC)
Miscellaneous bottom fish (KC)
Mesopelagic fish (OYC)
Mesopelagic fish (KC)
Mesopelagic fish (OF)Surface squids (all)Mesopelagic squids (all)Benthos (OYC)
Benthos (KC)
Krill (OYC)
Krill (OF)
Zooplankton (OYC)
Zooplankton (KC)
Zooplankton (OF)Phytoplankton (OYC)
Phytoplankton (KC)
Phytoplankton (OF)
Detritus (OYC)
Detritus (KC)
Detritus (OF)

Mesopelagic fish (OF)

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

Mesopelagic fish (KC)Prey/Predator

34

35

36

37

38

39

40

41

42

43

44

0.005
0.036
0.005
0.005
0.005

0.015
0.015
0.270
0.004
0.005

0.015
0.015
0.270
0.005
0.005

0.003

0.015
0.285
0.017
0.017
0.301

0.015
0.285
0.019
0.019
0.352

0.003

0.001
0.143

0.250

0.001
0.143

0.300
0.750
0.700

0.003
0.099

0.200

0.100

0.102

0.100
0.200

0.121

0.500

0.100
0.600

0.121

0.600
0.500

0.630

0.300
0.630

15

0.600
0.300
0.300

Table 6. Fishery landings in the western North Pacific in 2013 and 1994 used in Ecopath. Values changed fromthe 2013 to 1994 are in italic with underline.
Species/groups
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

Blue whale (OYC, OF)
Fin whale (OYC, OF)
Sei whale (OYC, OF)
Bryde's whale (OYC, OF)
Common minke whale (OYC, OF)
Humpback whale (OYC, OF)
Sperm whale (OYC, OF)
Killer whale (all)Large dolphins (all)Small dolphins (all)Dall's porpoise (OYC, OF)
Pilot whales (all)Baird's beaked whale (OYC)
Beaked whales (all)Seabirds (all)Blue shark (all)Mesopelagic sharks (OYC)
Tunas (all)Skipjack (all)Swordfish (all)Miscellaneous piscivores (all)Japanese sardine (all)Japanese anchovy (all)Pacific saury (all)Chub mackerel (all)Spotted mackerel (all)Righteye flounders (OYC)
Alaska pollock (OYC)
Miscellaneous bottom fish (OYC)
Righteye flounders (KC)
Seabreams (KC)
Miscellaneous bottom fish (KC)
Mesopelagic fish (OYC)
Mesopelagic fish (KC)
Mesopelagic fish (OF)Surface squids (all)Mesopelagic squids (all)Benthos (OYC)
Benthos (KC)
Krill (OYC)
Krill (OF)
Zooplankton (OYC)
Zooplankton (KC)
Zooplankton (OF)Phytoplankton (OYC)
Phytoplankton (KC)
Phytoplankton (OF)
Detritus (OYC)
Detritus (KC)
Detritus (OF)16

Landing (t/km^2/year)
2013
1994
0.000500.000180.00009
0.000030.000020.000030.00004
0.000020.000030.000020.000260.000030.00004
0.00005
0.00005
0.000520.000620.00006
0.000100.002470.001800.000500.00104
0.00006
0.00006
0.018900.11300
0.062700.02900
0.12080
0.08600
0.045400.03100
0.042800.01900
0.000410.000440.083130.110900.00647
0.002350.00001
0.00001
0.00004
0.00004
0.000370.00037
0.025160.025160.000020.000020.000020.000020.00699
0.00699-

Table 7. Time series data used for time series fitting in Ecosim in the western North Pacific from 1994 to 2013.
Species/group
Sei whale

Bryde's whale

Common minke whale

Sperm whale

Blue shark

Tunas

Skipjack

Japanese sardine

Japanese anchovy

Pacific saury

Chub mackerel

Time series
Biomass
CatchFishing mortality
Biomass
CatchFishing mortality
Biomass
CatchFishing mortality
Biomass
CatchFishing mortality
Biomass
CatchFishing mortality
Total mortality
Biomass
CatchFishing mortality
Total mortality
Biomass
CatchFishing mortality
Total mortality
Biomass
CatchFishing mortality
Total mortality
Biomass
CatchFishing mortality
Total mortality
Biomass
Catch
Biomass
CatchFishing mortality
Total mortality
Biomass

Spotted mackerel

Alaska pollock

Zooplankton (OYC)
Zooplankton (KC)
Phytoplankton (OYC)
Phytoplankton (KC)
Phytoplankton (OF)CatchFishing mortality
Total mortality
Biomass
CatchFishing mortality
Total mortality
Biomass
Biomass
Biomass
Biomass
BiomassYear
1994-2013 (20 years)

1994-2013 (20 years)

1994-2013 (20 years)

1994-2013 (20 years)

1994-2013 (20 years)*Same value as in 2012 was allocated to 2013

1994-2013 (20 years)*Same value as in 2012 was allocated to 2013

1994-2013 (20 years)*Same value as in 2012 was allocated to 2013

1994-2013 (20 years)

1994-2013 (20 years)

2003-2013 (11 years)
1994-2013 (20 years)

1994-2013 (20 years)

1994-2013 (20 years)*Same value as chub mackerel in 1994 was allocated to 1994
1994-2013 (20 years)
1994-2013 (20 years)*Same value as chub mackerel in 1994 was allocated to 1994

1994-2013 (20 years)

1994-2013 (20 years)
1994-2013 (20 years)
2003-2013 (11 years)
2003-2013 (11 years)
2003-2013 (11 years)

17

Table 8. Estimated basic parameters for Ecopath in the western North Pacific in 2013. OYC: coastal Oyasio block,
KC: coastal Kuroshio block, OF: offshore block, B in habitat: biomass (t/km2) in distributed blocks, B: biomass(t/km2) in the entire modelled area, P/B: production/biomass ratio, Q/B: consumption/biomass ratio, EE:
ecotrophic efficiency and P/Q: production/consumption ratio.
Species/group

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

Blue whale (OYC, OF)
Fin whale (OYC, OF)
Sei whale (OYC, OF)
Bryde's whale (OYC, OF)
Common minke whale (OYC, OF)
Humpback whale (OYC, OF)
Sperm whale (OYC, OF)
Killer whale (all)Large dolphins (all)Small dolphins (all)Dall's porpoise (OYC, OF)
Pilot whales (all)Baird's beaked whale (OYC)
Beaked whales (all)Seabirds (all)Blue shark (all)Mesopelagic sharks (OYC)
Tunas (all)Skipjack (all)Swordfish (all)Miscellaneous piscivores (all)Japanese sardine (all)Japanese anchovy (all)Pacific saury (all)Chub mackerel (all)Spotted mackerel (all)Righteye flounders (OYC)
Alaska pollock (OYC)
Miscellaneous bottom fish (OYC)
Righteye flounders (KC)
Seabreams (KC)
Miscellaneous bottom fish (KC)
Mesopelagic fish (OYC)
Mesopelagic fish (KC)
Mesopelagic fish (OF)Surface squids (all)Mesopelagic squids (all)Benthos (OYC)
Benthos (KC)
Krill (OYC)
Krill (OF)
Zooplankton (OYC)
Zooplankton (KC)
Zooplankton (OF)Phytoplankton (OYC)
Phytoplankton (KC)
Phytoplankton (OF)
Detritus (OYC)
Detritus (KC)
Detritus (OF)TL

Habitatarea(fraction)

B inhabitat

B

P/B

Q/B

EE

P/Q

3.222
3.285
3.742
3.920
4.106
3.558
4.464
4.395
4.389
4.347
4.183
4.464
4.633
4.368
4.106
4.292
4.445
4.426
4.221
4.259
3.945
2.560
3.111
3.133
3.418
3.429
3.388
3.594
3.640
3.291
3.232
3.565
3.216
3.161
3.144
3.525
3.470
2.310
2.310
2.222
2.222
2.111
2.111
2.111
1.000
1.000
1.000
1.000
1.000
1.000

0.950
0.950
0.950
0.950
0.950
0.950
0.950
1.000
1.000
1.000
1.000
0.950
0.050
1.000
1.000
1.000
0.050
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
0.050
0.050
0.050
0.050
0.050
0.050
0.050
0.050
0.900
1.000
1.000
0.050
0.050
0.050
0.900
0.050
0.050
0.900
0.050
0.050
0.900
0.050
0.050
0.900

0.022
0.053
0.034
0.035
0.006
0.009
0.160
0.002
0.003
0.025
0.002
0.002
0.049
0.004
0.003
0.089
0.107
0.036
0.027
0.001
0.046
0.446
1.156
0.851
1.240
1.009
0.946
4.889
14.138
0.001
0.003
0.025
11.423
3.009
2.935
0.042
0.846
64.5344.181
114.489
23.39229.7308.067
11.643
13.55510.0129.036
47.91130.18447.499

0.021
0.050
0.032
0.033
0.006
0.009
0.152
0.002
0.003
0.025
0.002
0.002
0.002
0.004
0.003
0.089
0.005
0.036
0.027
0.001
0.046
0.446
1.156
0.851
1.240
1.009
0.047
0.244
0.707
0.000
0.000
0.001
0.571
0.150
2.642
0.042
0.846
3.227
0.209
5.724
21.0531.487
0.403
10.479
0.678
0.501
8.132
2.396
1.509
42.749

0.040
0.052
0.099
0.087
0.120
0.072
0.061
0.100
0.120
0.143
0.138
0.147
0.105
0.100
0.120
0.464
0.330
0.326
0.458
0.490
2.250
0.517
2.180
1.523
0.513
0.486
0.446
0.840
0.393
0.446
0.490
0.346
1.500
1.500
1.500
2.555
2.979
3.030
2.530
2.555
2.555
23.16023.16023.160153.776
128.274
153.776

4.220
4.548
4.384
7.372
4.581
4.634
8.696
4.381
7.778
10.777
11.49214.2874.872
7.855
36.667
1.325
2.900
6.754
16.200
2.500
7.700
2.585
10.900
7.615
2.565
2.430
2.893
2.212
3.182
2.893
2.450
2.832
6.000
6.000
6.000
7.300
13.641
10.1028.430
12.04512.04545.35045.35045.350
0.000
0.000
0.000

0.010
0.003
0.159
0.065
0.144
0.014
0.003
0.000
0.108
0.008
0.104
0.139
0.228
0.022
0.000
0.013
0.039
0.327
0.134
0.301
0.950
0.454
0.733
0.169
0.202
0.256
0.576
0.491
0.653
0.614
0.592
0.865
0.900
0.900
0.900
0.950
0.938
0.706
0.915
0.189
0.286
0.751
0.398
0.529
0.758
0.177
0.330
0.728
0.104
0.190

0.009
0.011
0.023
0.012
0.026
0.016
0.007
0.023
0.015
0.013
0.012
0.010
0.022
0.013
0.003
0.350
0.114
0.048
0.028
0.196
0.292
0.200
0.200
0.200
0.200
0.200
0.154
0.380
0.124
0.154
0.200
0.122
0.250
0.250
0.250
0.350
0.218
0.300
0.300
0.212
0.212
0.511
0.511
0.511

18

Table 9. Estimated basic parameters for Ecopath in the western North Pacific in 1994. OYC: coastal Oyasio block,
KC: coastal Kuroshio block, OF: offshore block, B in habitat: biomass (t/km2) in distributed blocks, B: biomass(t/km2) in the entire modelled area, P/B: production/biomass ratio, Q/B: consumption/biomass ratio, EE:
ecotrophic efficiency and P/Q: production/consumption ratio.
Species/group

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50

Blue whale (OYC, OF)
Fin whale (OYC, OF)
Sei whale (OYC, OF)
Bryde's whale (OYC, OF)
Common minke whale (OYC, OF)
Humpback whale (OYC, OF)
Sperm whale (OYC, OF)
Killer whale (all)Large dolphins (all)Small dolphins (all)Dall's porpoise (OYC, OF)
Pilot whales (all)Baird's beaked whale (OYC)
Beaked whales (all)Seabirds (all)Blue shark (all)Mesopelagic sharks (OYC)
Tunas (all)Skipjack (all)Swordfish (all)Miscellaneous piscivores (all)Japanese sardine (all)Japanese anchovy (all)Pacific saury (all)Chub mackerel (all)Spotted mackerel (all)Righteye flounders (OYC)
Alaska pollock (OYC)
Miscellaneous bottom fish (OYC)
Righteye flounders (KC)
Seabreams (KC)
Miscellaneous bottom fish (KC)
Mesopelagic fish (OYC)
Mesopelagic fish (KC)
Mesopelagic fish (OF)Surface squids (all)Mesopelagic squids (all)Benthos (OYC)
Benthos (KC)
Krill (OYC)
Krill (OF)
Zooplankton (OYC)
Zooplankton (KC)
Zooplankton (OF)Phytoplankton (OYC)
Phytoplankton (KC)
Phytoplankton (OF)
Detritus (OYC)
Detritus (KC)
Detritus (OF)TL

Habitatarea(fraction)

B inhabitat

B

P/B

Q/B

EE

P/Q

3.222
3.285
3.742
3.920
4.106
3.558
4.464
4.395
4.389
4.347
4.183
4.464
4.633
4.368
4.106
4.292
4.445
4.426
4.221
4.259
3.945
2.560
3.111
3.133
3.418
3.429
3.388
3.594
3.640
3.291
3.232
3.565
3.216
3.161
3.144
3.525
3.470
2.310
2.310
2.222
2.222
2.111
2.111
2.111
1.000
1.000
1.000
1.000
1.000
1.000

0.950
0.950
0.950
0.950
0.950
0.950
0.950
1.000
1.000
1.000
1.000
0.950
0.050
1.000
1.000
1.000
0.050
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
0.050
0.050
0.050
0.050
0.050
0.050
0.050
0.050
0.900
1.000
1.000
0.050
0.050
0.050
0.900
0.050
0.050
0.900
0.050
0.050
0.900
0.050
0.050
0.900

0.022
0.053
0.024
0.038
0.006
0.009
0.136
0.002
0.003
0.025
0.002
0.002
0.049
0.004
0.003
0.077
0.107
0.051
0.037
0.001
0.064
1.276
0.920
0.851
0.494
0.494
0.946
5.211
14.138
0.001
0.003
0.025
11.413
2.897
2.822
0.039
0.790
64.5344.030
114.489
23.39223.4508.487
11.643
13.55510.0129.036
47.91130.18447.499

0.021
0.050
0.023
0.036
0.006
0.009
0.129
0.002
0.003
0.025
0.002
0.002
0.002
0.004
0.003
0.077
0.005
0.051
0.037
0.001
0.064
1.276
0.920
0.851
0.494
0.494
0.047
0.261
0.707
0.000
0.000
0.001
0.571
0.145
2.539
0.039
0.790
3.227
0.201
5.724
21.0531.173
0.424
10.479
0.678
0.501
8.132
2.396
1.509
42.749

0.040
0.052
0.099
0.087
0.120
0.072
0.061
0.100
0.120
0.143
0.138
0.147
0.105
0.100
0.120
0.727
0.330
0.299
0.468
0.490
2.250
0.613
2.019
1.523
0.497
0.497
0.446
0.840
0.393
0.446
0.490
0.346
1.500
1.500
1.500
2.555
2.979
3.030
2.530
2.555
2.555
23.16023.16023.160153.776
128.274
153.776

4.220
4.548
4.384
7.372
4.581
4.634
8.696
4.381
7.778
10.777
11.49214.2874.872
7.855
36.667
1.325
2.900
6.754
16.200
2.500
7.700
3.065
10.095
7.615
2.485
2.485
2.893
2.212
3.182
2.893
2.450
2.832
6.000
6.000
6.000
7.300
13.641
10.1028.430
12.04512.04545.35045.35045.350
0.000
0.000
0.000

0.010
0.003
0.004
0.003
0.057
0.014
0.001
0.000
0.135
0.011
0.974
0.175
0.228
0.022
0.000
0.011
0.062
0.240
0.150
0.301
0.950
0.217
0.587
0.158
0.542
0.493
0.578
0.588
0.636
0.614
0.592
0.865
0.900
0.900
0.900
0.950
0.938
0.706
0.915
0.182
0.240
0.896
0.374
0.518
0.677
0.186
0.331
0.677
0.108
0.190

0.009
0.011
0.023
0.012
0.026
0.016
0.007
0.023
0.015
0.013
0.012
0.010
0.022
0.013
0.003
0.549
0.114
0.044
0.029
0.196
0.292
0.200
0.200
0.200
0.200
0.200
0.154
0.380
0.124
0.154
0.200
0.122
0.250
0.250
0.250
0.350
0.218
0.300
0.300
0.212
0.212
0.511
0.511
0.511

19

Table 10. Results of time series fitting using Ecosim in the western North Pacific from 1994 to 2013. Number of
predator/prey blocks
Searchcategory

Assignment of time series data

Base case(v=2),
time series
loadedAll relative biomass and catch time series are used as reference
All but biomass of anchovy is used as forced time series
All but biomass of anchovy and sardine is used as forced time series
All but biomasses of anchovy, sardine and chub mackerel are used as forced time series
All but biomasses of anchovy, sardine and, chub and spotted mackerel are used as forced time series
All relative biomass and catch are used as reference

All but biomass of anchovy is used as forced time series

Search bypredator/prey

All but biomass of anchovy and sardine is used as forced time series

All but biomasses of anchovy, sardine and chub mackerel are used as forced time series

All but biomasses of anchovy, sardine and, chub and spotted mackerel are used as forced time series

20

Model
numberNumber of
predator/preyblocks

SS

AIC

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

5
10
20
5
10
20
5
10
20
5
10
20
5
10
20

93.4
74.8
47.6
36.8
34.1
66.4
63.3
63.0
64.9
61.8
60.9
37.5
37.4
36.5
30.6
29.1
27.1
27.4
22.9
22.0

438
443.1
462.6
435.7
440.6
459.1
379.8
389.5
407
359
363.9
376.6
347.8
339.2
355.2

Table 11. Estimated vulnerability parameters (v) based on model number 19 in Table 10.
Predator / prey
Blue shark (all) / Japanese anchovy (all)Blue shark (all) / Mesopelagic squids (all)Skipjack (all) / Mesopelagic squids (all)Japanese anchovy (all) / Zooplankton (OF)Chub mackerel (all) / Japanese anchovy (all)Chub mackerel (all) / Krill (OF)Chub mackerel (all) / Zooplankton (OF)Spotted mackerel (all) / Japanese anchovy (all)Spotted mackerel (all) / Krill (OF)Spotted mackerel (all) / Zooplankton (OF)21

Estimated v
>10
1
1
>10
>10
>10
>10
1
>10
>10

Fig. 1. Schematic map of Ecopath with Ecosim modelling area in the western North Pacific.

22

Fig. 2. Annual mean of Pacific Decadal Oscillation (PDO) index from 1956 to 2012 (top) and landing of small
pelagic fish (Japanese sardine, Japanese anchovy, mackerels and Pacific saury) from 1956 to 2012 (bottom).
Monthly PDO data available from “http://research.jisao.washington.edu/pdo/” (accessed on 6 October 2015) areused to calculate annual mean. Landing data are extracted from “Statistics of Agriculture, Forestry and Fisheries”(available http://www.e-stat.go.jp; accessed on 28 November 2015). Climate regime shift indicated in several
published papers are also shown in the figure as black lines. Sea surface temperature in the eastern Pacific is highin the positive phase while that in the western Pacific is low. Vice versa is true for the negative phase. Scales oflanding are different from Japanese anchovy and Pacific saury (left axis) and Japanese sardine and mackerels (rightaxis).

23

Fig. 3. Annual mean of Pacific Decadal Oscillation (PDO) index from 1994 to 2013 (top) and landing of small
pelagic fish (Japanese sardine, Japanese anchovy, mackerels and Pacific saury) from 1994 to 2013 (bottom).
Monthly PDO data available from “http://research.jisao.washington.edu/pdo/” (accessed on 6 October 2015) areused to calculate annual mean. Landing data in the stock assessment report (Fisheries Agency and Fisheries
Research Agency of Japan, 2015) are used.

24

5

Baird's beaked whale (OYC)
Pilot whales (all)Sperm whale (OYC, OF)
Large dolphins (all)Killer whale (all)Beaked whales (all)Mesopelagic sharks (OYC)

Tunas (all)Small dolphins (all)Blue shark (all)Dall's porpoise (OYC, OF)

Skipjack (all)Common minke whale (OYC, OF)

Swordfish (all)Seabirds (all)4
Miscellaneous piscivores (all)Bryde's whale (OYC, OF)
Sei whale (OYC, OF)
Alaska pollock (OYC)

Miscellaneous bottom fish (OYC)

Humpback whale (OYC, OF)
Surface squids (all)Mesopelagic squids (all)Righteye flounders (OYC)
Blue whale (OYC, OF)

Chub mackerel (all)Fin whale (OYC, OF)

Seabreams (KC)

Mesopelagic fish (OYC)
3

Miscellaneous bottom fish (KC)
Sptted chub mackerel (all)Mesopelagic fish (OF)

Pacific saury (all)Righteye flounders (KC)
Mesopelagic fish (KC)Japanese anchovy (all)Japanese sardine (all)Benthos (KC)
Benthos (OYC)
2

Krill (OYC)

Zooplankton (OYC)
Zooplankton (OF)

Zooplankton (KC)

Krill (OF)1
Phytoplankton (OYC)

Phytoplankton (KC)

Detritus (OYC)

Phytoplankton (OF)

Detritus (KC)

Detritus (OF)Fig. 4. Food web of the western North Pacific in 2013 estimated by Ecopath. Numbers (1-5) in the left indicate trophic levels. Size of bubbles represents biomass of eachspecies/group. Colours of bubble indicate allocation of spatial blocks for species/groups. Blue: coastal Oyashio block, red: coastal Kuroshio block, light green: offshore block(OF), purple: OYC and OF blocks and sky blue: all blocks.

25

.
5

Baird’s beaked whale (OYC)
Pilot whales (all)Sperm whale (OYC, OF)
Large dolphins (all)Killer whale (all) Beaked whales (all)Mesopelagic sharks (OYC)

Tunas (all)Small dolphins (all)Blue shark (all)Dall's porpoise (OYC, OF)

Skipjack (all)Common minke whale (OYC, OF)

Swordfish (all)Seabirds (all)4
Miscellaneous piscivores (all)Bryde's whale (OYC, OF)
Sei whale (OYC, OF)
Alaska pollock (OYC)

Miscellaneous bottom fish (OYC)

Humpback whale (OYC, OF)
Surface squids (all)Mesopelagic squids (all)Righteye flounders (OYC)
Bue whale (OYC, OF)

Sptted chub mackerel (all)Chub mackerel (all)Fin whale (OYC, OF)

Seabreams (KC)

Mesopelagic fish (OYC)
3

Miscellaneous bottom fish (KC)

Mesopelagic fish (OF)

Pacific saury (all)Righteye flounders (KC)
Mesopelagic fish (KC)Japanese anchovy (all)Japanese sardine (all)Benthos (KC)
Benthos (OYC)
2

Krill (OYC)

Zooplankton (OYC)
Zooplankton (OF)

Zooplankton (KC)

Krill (OF)1
Phytoplankton (OYC)

Phytoplankton (KC)

Detritus (OYC)

Phytoplankton (OF)

Detritus (KC)

Detritus (OF)Fig. 5. Food web of the western North Pacific in 1994 estimated by Ecopath. Numbers (1-5) in the left indicate trophic levels. Size of bubbles represents biomass of eachspecies/group. Colours of bubble indicate allocation of spatial blocks for species/groups. Blue: coastal Oyashio block, red: coastal Kuroshio block, light green: offshore block(OF), purple: OYC and OF blocks and sky blue: all blocks.

26

Fig. 6. Mixed trophic impact (MTI) relationships between species/groups in the western North Pacific in 2013.
Values represents by colours indicated positive or negative impact by impacting species/groups on impacted
species/groups.

27

Fig. 7. Mixed trophic impact (MTI) relationships between species/groups in the western North Pacific in 1994.
Values represents by colours indicated positive or negative impact by impacting species/groups on impacted
species/groups.

28

Fig. 8. Input time series data (circles) and estimated time series (lines) for biomass (B) by Ecosim in the western
North Pacific from 1994 to 2013. Results of models with (model number 19 in Table 10; top) or without (model
number 7 in Table 10; bottom) forcing on biomass time series of forage fish are shown.

29

Fig. 9. Input time series data (circles) and estimated time series (lines) for total mortality (Z) by Ecosim in thewestern North Pacific from 1994 to 2013. Results of models with (model number 19 in Table 10; top) or without(model number 7 in Table 10; bottom) forcing on biomass time series of forage fish are shown.

30

Fig. 10.

Fig. 10. Input time series data (circles) and estimated time series (lines) of catch (C) by Ecosim in the western
North Pacific from 1994 to 2013. Results of models with (model number 19 in Table 10; top) or without (model
number 7 in Table 10; bottom) forcing on biomass time series of forage fish are shown.

31

Appendix 1
Details of basic input parameters for Ecopath with
Ecosim (EwE) in the western North Pacific in 2013 and1994
This is Appendix 1 of “SC/F16/JR28. Murase, H., Tamura, T., Hakamada, T., Watari, S., Okazaki, M.,
Kiyofuji, H, Yonezaki, S and Kitakado, T. 2015 Ecosystem modelling in the western North Pacific from1994 to 2013 using Ecopath with Ecosim (EwE): some preliminary results. Paper SC/F16/JR28 presented
to the JARPNII special permit expert panel review workshop, Tokyo, February 2016 (unpublished)”.
1. BLUE WHALE
Species
One species, blue whale (Balaenoptera musculus), is considered.
Distribution blocks
It is assumed that this species is distributed in OYC and OF.
Biomass (B)Biomass is calculated using the latest abundance estimate (615 individuals) in JARPNII area (Hakamada
and Matsuoka, 2016a: SC/F16/JR13) and mean body weight (102,737 kg) from Trites and Pauly (1998).
Weighted mean (by number of month) of abundance estimates in early season (May-June) in 2011 and2012, and late season (July-September) in 2008 is used. The same value is assumed in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Mean of M1 and M2 (0.040) in the North Pacific in Table 2 of Ohsumi (1979) is used. There is no fishingmortality between 1994 and 2013. The same value is assumed in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The calculation method described in Tamura et al. (2016:SC/F16/JR15) are adopted. For this paper, meanof standard metabolic rate (SMRs) calculated by using 3 equations (Boyd, 2002; Perez et al., 1990;
Sigurjonsson and Vikingsson, 1997) is calculated. The same value is assumed in 2013 and 1994.
Diet compositions
It is assumed that this species feeds exclusively on krill. The same compositions are assumed in 2013 and
1994.
Catch
There is no catch from 1994 to 2013.
2. FIN WHALE
Species
One species, fin whale (Balaenoptera physalus), is considered.
Distribution blocks
It is assumed that this species is distributed in OYC and OF.

32

Biomass (B)Biomass is calculated using the latest abundance estimate (2,731 individuals) in JARPNII area (Hakamada
and Matsuoka, 2016a: SC/F16/JR13) and mean body weight (55,590 kg) from Trites and Pauly (1998).
Weighted mean (by number of month) of abundance estimates in early season (May-June) in 2011 and2012, and late season (July-September) in 2008 is used. The same value is assumed in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Mean of M1 and M2 (0.052) in the Northern Hemisphere in Table 2 of Ohsumi (1979) is used. There is no
fishing mortality between 1994 and 2013. The same value is assumed in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The methods described in Tamura et al. (2016: SC/F16/JR15) are adopted. For this paper, mean of standard
metabolic rate (SMRs) calculated by using 3 equations (Boyd, 2002; Perez et al., 1990; Sigurjonsson andVikingsson, 1997) is calculated. The same value is assumed in 2013 and 1994.
Diet compositions
The standardized diet compositions for this species described in Pauly et al. (1998) are used as the basic
information. Specific diet compositions based on the information are then assigned based on the authors’expert knowledge. The same compositions are assumed in 2013 and 1994.
Catch
There is no catch from 1994 to 2013.
3. SEI WHALE
Species
One species, sei whale (Balaenoptera borealis), is considered.
Distribution blocks
It is assumed that this species is distributed in OYC and OF.
Biomass (B)Biomass in 2013 is calculated using the latest abundance estimate (5,185 individuals) in JARPNII area
(Hakamada and Matsuoka, 2016c: SC/F16/JR12) and mean body weight (18,715 kg) in JARPNII area
(Tamura et al., 2016). Weighted mean (by number of month) of abundance estimates in early season (MayJune), and late season (July-September) from 2008 to 2014 is used. Time series of abundance in JARPNII
area from 1994 to 2013 is estimated applying Hitter-Fitter model using abundance estimates from JARPNII
and POWER (Hakamada, unpublished data). One stock scenario is assumed. Biological parameters used in
the model are as followed: age of maturity = 6.0 years old, natural mortality = 0.08/year, MSY level = 60%(of K). MSYR (mature) = 4% is assumed in the model. The time series estimated by Hitter-Fitter model isthen scaled to size of JARPNII area. Above mentioned mean body weight is used to calculate biomass inthe time series
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
M = 0.08 is used assuming that the value is same as Bryde’s whale (IWC, 2008). F in 2013 is calculatedusing JARPNII data. The same P/B is assumed in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The methods described in Tamura et al. (2016: SC/F16/JR15) are adopted. For this paper, mean of standard
metabolic rate (SMRs) calculated by using 3 equations (Boyd, 2002; Perez et al., 1990; Sigurjonsson andVikingsson, 1997) is calculated. The same value is assumed in 2013 and 1994.

33

Diet compositions
The diet compositions described in Tamura et al. (2016) are used but the species is allowed to feed onJapanese sardine in proportion of 0.01. The same compositions are assumed in 2013 and 1994.
Catch
There are no catch from 1994 to 2001. Catch data from JARPNII are used onward. Above mentioned mean
body weight is used to calculate the catch biomass.
4. BRYDE'S WHALE
Species
One species, Bryde’s whale (Balaenoptera edeni in the sense of IWC), is considered.
Distribution blocks
It is assumed that this species is distributed in OYC and OF.
Biomass (B)Biomass in 2013 is calculated using the latest abundance estimate (7,644 individuals) in JARPNII area
(Hakamada and Matsuoka, 2016c: SC/F16/JR12) and mean body weight (13,078 kg) in JARPNII area
(Tamura et al., 2016). Weighted mean (by number of month) of abundance estimates in early season (MayJune), and late season (July-September) from 2008 to 2014 is used. Time series of abundance in JARPNII
area in from 1994 to 2013 is estimated applying Hitter-Fitter model using abundance estimates by Kitakado
et al. (2008) (Hakamada, unpublished data). One stock in sub-area 1 is assumed. Biological parameters
used in the model are as followed: age of maturity = 6.0 years old, natural mortality = 0.08/year, MSY level= 60% (of K). MSYR (mature) = 4% is assumed in the model. The time series estimated by Hitter-Fittermodel is then scaled to size of JARPNII area. Above mentioned mean body weight is used to calculatebiomass in the time series.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
M = 0.08 is used (IWC, 2008). F in 2013 is calculated using JARPNII data. The same P/B is assumed in2013 and 1994.
Consumption/biomass ratio (Q/B)
The methods described in Tamura et al. (2016: SC/F16/JR15) are adopted. For this paper, mean of standard
metabolic rate (SMRs) calculated by using 3 equations (Boyd, 2002; Perez et al., 1990; Sigurjonsson andVikingsson, 1997) is calculated. The same value is assumed in 2013 and 1994.
Diet compositions
The diet compositions described in Tamura et al. (2016) are used but the species is allowed to feed onJapanese sardine in proportion of 0.01. The same compositions are assumed in 2013 and 1994.
Catch
There are no catch from 1994 to 1999. Catch data from JARPNII are used onward. Above mentioned mean
body weight is used to calculate the catch biomass.
5. COMMON MINKE WHALE
Species
One species, common minke whale (Balaenoptera acutorostrata), is considered.
Distribution blocks
It is assumed that this species is distributed in OYC and OF.

34

Biomass (B)Biomass in 2013 is calculated using the latest abundance estimate (3,435 individuals) in JARPNII area
(Hakamada and Matsuoka, 2016c: SC/F16/JR12) and mean body weight (4,766 kg) in JARPNII area
(Tamura et al., 2016). Weighted mean (by number of month) of abundance estimates in early season (MayJune), and late season (July-September) from 2008 to 2014 is used. Time series of abundance in JARPNII
area from 1994 to 2013 based on Hitter-Fitter model is used. The methods described in Hakamada (2009)is used. The time series of O-stock and J-stock are combined in this paper. The time series is then scalded
to JARPNII area. Above mentioned mean body weight is used to calculate biomass in the time series.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
M = 0.1 is used taking mean of M for 4 years old and 20+ years old (IWC, 2014). F in 2013 is calculatedusing JARPNII data. The same P/B is assumed in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The methods described in Tamura et al. (2016: SC/F16/JR15) are adopted. For this paper, mean of standard
metabolic rate (SMRs) calculated by using 3 equations (Boyd, 2002; Perez et al., 1990; Sigurjonsson andVikingsson, 1997) is calculated. The same value is assumed in 2013 and 1994.
Diet compositions
The diet compositions described in Tamura et al. (2016) are used but the species is allowed to feed onJapanese sardine in proportion of 0.01. The same compositions are assumed in 2013 and 1994.
Catch
Catch data from JARPN and JARPNII (1994 to 2013) are used. Above mentioned mean body weight isused to calculate the catch biomass.
6. HUMPBACK WHALE
Species
One species, humpback whale (Megaptera novaeangliae), is considered.
Distribution blocks
It is assumed that this species is distributed in OYC and OF.
Biomass (B)Biomass is calculated using the latest abundance estimate (847 individuals) in JARPNII area (Hakamada
and Matsuoka, 2016a: SC/F16/JR13) and mean body weight (30,408 kg) from Trites and Pauly (1998).
Weighted mean (by number of month) of abundance estimates in early season (May-June) in 2011 and2012, and late season (July-September) in 2008 is used. The same value is assumed in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Mean of M1 and M2 (0.072) in the Northern Pacific in Table 2 of Ohsumi (1979) is used. There is no
fishing mortality between 1994 and 2013. The same value is assumed in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The methods described in Tamura et al. (2016: SC/F16/JR15) are adopted. For this paper, mean of standard
metabolic rate (SMRs) calculated by using 3 equations (Boyd, 2002; Perez et al., 1990; Sigurjonsson andVikingsson, 1997) is calculated. The same value is assumed in 2013 and 1994.
Diet compositions
The standardized diet compositions for this species described in Pauly et al. (1998) are used as the basic
information. Specific diet compositions based on the information are then assigned based on the authors’expert knowledge. The same compositions are assumed in 2013 and 1994.

35

CatchThere is no catch from 1994 to 2013.
7. SPERM WHALE
Species
One species, sperm whale (Physeter macrocephalus), is considered.
Distribution blocks
It is assumed that this species is distributed in OYC and OF.
Biomass (B)Biomass is calculated using the latest abundance estimate (14,088 individuals) in JARPNII area (Hakamada
and Matsuoka, 2016b: SC/F16/JR14) and mean body weight (30,408 kg) from Trites and Pauly (1998).
Weighted mean (by number of month) of abundance estimates in early season (May-June) in 2011 and2012, and late season (July-September) in 2008 is used. Time series of abundance from 1994 to 2013 isestimated using a method described in Whitehead (2002). Abundance estimate described in Kato andMiyashita (1998) and catch data within the estimated area are used in the method. In contrast to the original
method, data from other regions (e.g. Atlantic) are not considered in this paper. The time series is thenscaled to JARPNII area. Above mentioned mean body weight is used to calculate the biomass in the timeseries.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
M=0.061 is used taking mean of female and male (IWC, 1983). F in 2013 is calculated based on JARPNII
data. The same value is assumed in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The methods described in Tamura et al. (2016: SC/F16/JR15) are adopted. For this paper, mean of standard
metabolic rate (SMRs) calculated by using 3 equations (Boyd, 2002; Perez et al., 1990; Sigurjonsson andVikingsson, 1997) is calculated. The same value is assumed in 2013 and 1994.
Diet compositions
The standardized diet compositions for this species described in Pauly et al. (1998) are used as the basic
information. Specific diet compositions based on the information are then assigned based on the authors’expert knowledge. The same compositions are assumed in 2013 and 1994.
Catch
There are no catch from 1994 to 1999. Catch data from JARPNII are used onward. Above mentioned mean
body weight is used to calculate the biomass
8. KILLER WHALE
Species
One species, killer whale (Orcinus orca), is considered.
Distribution blocks
It is assumed that this species is distributed in all blocks.
Biomass (B)Abundance within the EwE modelling area is estimated by using a generalized additive model (GAM)
based density surface model (Kanaji, unpublished data). Sighting data from 1983 and 2006 collected by
National Research Institute of Far Seas Fisheries are used in the analysis. Mean body weight (2,280 kg)
from Trites and Pauly (1998) is multiplied by abundance to calculate biomass. The same biomass is
assumed in 2013 and 1994.

36

Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
M=0.1 is assumed for this species as no information is available. There is no fishing mortality between
1994 and 2013. The same value is assumed in 2013 and 1994. It is assumed that this species
Consumption/biomass ratio (Q/B)
The calculation method described in Tamura et al. (2016: SC/F16/JR15) are adopted but it is assumed that
this species stays in the modelled area for 180 days. For this paper, mean of standard metabolic rate (SMRs)
calculated by using 3 equations (Boyd, 2002; Perez et al., 1990; Sigurjonsson and Vikingsson, 1997) is
calculated. The same value is assumed in 2013 and 1994.
Diet compositions
The standardized diet compositions for this species described in Pauly et al. (1998) are used as the basic
information. However, diet compositions for “high vertebrates” are reduced accordingly to balance Ecopath.
Specific diet compositions based on the information are then assigned based on published qualitative
information (Ohizumi, 2008) and the authors’ expert knowledge. The same compositions are assumed in2013 and 1994.
Catch
There is no catch from 1994 to 2013.
9. LARGE DOLPHINSSpecies
Bottlenose (Tursiops truncates) and Risso's (Grampus griseus) dolphins are included in the group.
Distribution blocks
It is assumed that this group is distributed in all blocks.
Biomass (B)Abundance within the EwE modelling area is estimated by using a generalized additive model (GAM)
based density surface model (Kanaji, unpublished data). Sighting data from 1983 and 2006 collected by
National Research Institute of Far Seas Fisheries are used in the analysis. Mean body weight from Trites
and Pauly (1998) weighted by biomass of each species (216 kg) is multiplied by abundance to calculatebiomass. The same biomass is assumed in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Mean of M1 and M2 (0.133) for bottlenose dolphin in the North Pacific in Table 2 of Ohsumi (1979) isused for this group as natural mortality for Risso's dolphin has not been documented. There is no fishingmortality between 1994 and 2013. The same value is assumed in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The calculation method described in Tamura et al. (2016: SC/F16/JR15) are adopted but it is assumed that
this group stays in the modelled area for 180 days. For this paper, mean of standard metabolic rate (SMRs)
calculated by using 3 equations (Boyd, 2002; Perez et al., 1990; Sigurjonsson and Vikingsson, 1997) is
calculated. The same value is assumed in 2013 and 1994.
Diet compositions
The standardized diet compositions described in Pauly et al. (1998) are used as the basic information. The
mean of compositions is calculated taking biomass as weight. Specific diet compositions based on theinformation are then assigned based on published qualitative information (Ohizumi, 2008) and the authors’expert knowledge. The same compositions are assumed in 2013 and 1994.

37

CatchCatch in 2013 is derived from Fisheries Agency and Fisheries Research Agency of Japan (2015a) while
Catch in 1994 is derived from Kasuya (2011).
10. SMALL DOLPHINSSpeciesRough-toothed (Steno bredanensis), spinner (Stenella longirostris), spotted (Stenella attenuata), striped(Stenella coeruleoalba), Delphinus spp. and Pacific white-sided (Lagenorhynchus obliquidens) dolphins
are included in this group.
Distribution blocks
It is assumed that this group is distributed in all blocks.
Biomass (B)Abundance within the EwE modelling area is estimated by using a generalized additive model (GAM)
based density surface model (Kanaji, unpublished data). Sighting data from 1983 and 2006 collected by
National Research Institute of Far Seas Fisheries are used in the analysis. Mean body weight from Trites
and Pauly (1998) weighted by biomass of each species (94 kg) is multiplied by abundance to calculatebiomass. The same biomass is assumed in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Mean (weighted by biomass) of M1 and M2 (0.137) for spinner, spotted and striped dolphins in the North
Pacific in Table 2 of Ohsumi (1979) is used for this group. Natural mortality for other species has not been
documented. Mean F (weighted by biomass) is estimated using biomass and catch data. Catch in 2013 isderived from Fisheries Agency and Fisheries Research Agency of Japan (2015a). The same value isassumed in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The calculation method described in Tamura et al. (2016: SC/F16/JR15) are adopted but it is assumed that
this group stays in the modelled area for 180 days. For this paper, mean of standard metabolic rate (SMRs)
calculated by using 3 equations (Boyd, 2002; Perez et al., 1990; Sigurjonsson and Vikingsson, 1997) is
calculated. The same value is assumed in 2013 and 1994.
Diet compositions
Mean standardized diet compositions (weighted by biomass) for this group is calculated using data in Paulyet al. (1998). It is used as the basic information. Specific diet compositions based on the information arethen assigned based on published qualitative information (Ohizumi, 2008) and the authors’ expert
knowledge. The same compositions are assumed in 2013 and 1994.
Catch
Catch in 2013 is derived from Fisheries Agency and Fisheries Research Agency of Japan (2015a) while
Catch in 1994 is derived from Kasuya (2011).
11. DALL'S PORPOISE
Species
One species, Dall's porpoise (Phocoenoides dalli), is considered. Types (Dalli- and Truei- types) are treatedcollectively.
Distribution blocks
It is assumed that this species is distributed in OYC and OF blocks.

38

Biomass (B)Abundance within the EwE modelling area is estimated by using a generalized additive model (GAM)
based density surface model (Kanaji, unpublished data). Sighting data from 1983 and 2006 collected by
National Research Institute of Far Seas Fisheries are used in the analysis. Mean body weight (61 kg) from
Trites and Pauly (1998) is multiplied by abundance to calculate biomass. The same biomass is assumed in2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Mean of M1 and M2 (0.138) for Dall's porpoise in the North Pacific in Table 2 of Ohsumi (1979) is used.
F in 2013 is calculated using biomass and catch data. Catch in 2013 is derived from Fisheries Agency and
Fisheries Research Agency of Japan (2015a). The same P/B is assumed in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The calculation method described in Tamura et al. (2016: SC/F16/JR15) are adopted but it is assumed that
this species stays in the modelled area for 180 days. For this paper, mean of standard metabolic rate (SMRs)
calculated by using 3 equations (Boyd, 2002; Perez et al., 1990; Sigurjonsson and Vikingsson, 1997) is
calculated. The same value is assumed in 2013 and 1994.
Diet compositions
The standardized diet compositions for this species described in Pauly et al. (1998) are used as the basic
information. Specific diet compositions based on the information are then assigned based on publishedqualitative information (Ohizumi, 2008) and the authors’ expert knowledge. The same compositions are
assumed in 2013 and 1994.
Catch
Catch in 2013 is derived from Fisheries Agency and Fisheries Research Agency of Japan (2015a) while
Catch in 1994 is derived from Kasuya (2011).
12. PILOT WHALESSpecies
False killer (Pseudorca crassidens), short-finned pilot (Globicephala macrorhynchus) and melon-headed(Peponocephala electra) whales are included in this group.
Distribution blocks
It is assumed that this species is distributed in all blocks.
Biomass (B)Abundance within the EwE modelling area is estimated by using a generalized additive model (GAM)
based density surface model (Kanaji, unpublished data). Sighting data from 1983 and 2006 collected by
National Research Institute of Far Seas Fisheries are used in the analysis. Mean body weight from Trites
and Pauly (1998) weighted by biomass of each species (616 kg) is multiplied by abundance to calculatebiomass. The same biomass is assumed in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Mean of M1 and M2 (0.111) for pilot whale in the North Atlantic in Table 2 of Ohsumi (1979) is used. F
in 2013 is calculated using biomass and catch data. Catch in 2013 is derived from Fisheries Agency and
Fisheries Research Agency of Japan (2015a). The same P/B is assumed in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The calculation method described in Tamura et al. (2016: SC/F16/JR15) are adopted but it is assumed that
this species stays in the modelled area for 180 days. For this paper, mean of standard metabolic rate (SMRs)
calculated by using 3 equations (Boyd, 2002; Perez et al., 1990; Sigurjonsson and Vikingsson, 1997) is
calculated. The same compositions are assumed in 2013 and 1994.

39

Diet compositions
The standardized diet compositions for this species described in Pauly et al. (1998) are used as the basic
information. The mean of compositions is calculated taking biomass as weight. Specific diet compositions
based on the information are then assigned based on published qualitative information (Ohizumi, 2008) andthe authors’ expert knowledge. The same compositions are assumed in 2013 and 1994.
Catch
Catch in 2013 is derived from Fisheries Agency and Fisheries Research Agency of Japan (2015a) while
Catch in 1994 is derived from Kasuya (2011).
13. BAIRD’S BEAKED WHALE
Species
One species, Baird’s beaked whale (Berardius bairdii), is considered.
Distribution blocks
It is assumed that this species is distributed in OYC block.
Biomass (B)Abundance estimated by Okamura et al. (2012) is used. Mean body weight (3136 kg) from Trites and Pauly(1998) is multiplied by abundance to calculate biomass. The same biomass is assumed in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Mean of M1 and M2 (0.083) for Baird’s beaked whale in the North Pacific in Table 2 of Ohsumi (1979) isused. F in 2013 is calculated using biomass and catch data. Catch in 2013 is derived from Fisheries Agency
and Fisheries Research Agency of Japan (2015a). The same P/B is assumed in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The calculation method described in Tamura et al. (2016: SC/F16/JR15) are adopted but it is assumed that
this species stays in the modelled area for 180 days. For this paper, mean of standard metabolic rate (SMRs)
calculated by using 3 equations (Boyd, 2002; Perez et al., 1990; Sigurjonsson and Vikingsson, 1997) is
calculated. The same value is assumed in 2013 and 1994.
Diet compositions
The standardized diet compositions for this species described in Pauly et al. (1998) are used as the basic
information. Specific diet compositions based on the information are then assigned based on publishedqualitative information (Ohizumi, 2008) and the authors’ expert knowledge. The same compositions are
assumed in 2013 and 1994.
Catch
Catch in 2013 is derived from Fisheries Agency and Fisheries Research Agency of Japan (2015a) while
Catch in 1994 is derived from Kasuya (2011).
14. BEAKED WHALESSpeciesSpecies belonging to Ziphiidae (beaked whales, apart from Baird’s beaked whale) are included in the group.
Distribution blocks
It is assumed that this group is distributed in all blocks.
Biomass (B)Abundance within the EwE modelling area is estimated by using a generalized additive model (GAM)
based density surface model (Kanaji, unpublished data). Sighting data from 1983 and 2006 collected by
National Research Institute of Far Seas Fisheries are used in the analysis. Mean body weight (216 kg) of40

following species from Trites and Pauly (1998) is multiplied by abundance to calculate biomass:
Longman’s (Indopacetus pacificus), Blainville’s (Mesoplodon densirostris), Stejneger’s (Mesoplodon
stejnegeri), Ginkgo-toothed (Mesoplodon gingkodens), . Hubb’s (Mesoplodon carlhubbsi) and Cuvier’s(Ziphius cavirostris) beaked whales. The same biomass is assumed in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
M=0.1 is assumed for this species as no information is available. There is no fishing mortality between
1994 and 2013. The same value is assumed in 2013 and 1994. It is assumed that this species.
Consumption/biomass ratio (Q/B)
The calculation method described in Tamura et al. (2016: SC/F16/JR15) are adopted but it is assumed that
this species stays in the modelled area for 180 days. For this paper, mean of standard metabolic rate (SMRs)
calculated by using 3 equations (Boyd, 2002; Perez et al., 1990; Sigurjonsson and Vikingsson, 1997) is
calculated. The same value is assumed in 2013 and 1994.
Diet compositions
The standardized diet compositions described in Pauly et al. (1998) are used as the basic information. The
mean of compositions of above mentioned species is calculated. Specific diet compositions based on theinformation are then assigned based on published qualitative information (Ohizumi, 2008) and the authors’expert knowledge. The same compositions are assumed in 2013 and 1994.
Catch
There is no catch from 1994 to 2013.
15. SEABIRDS
Species
Black-footed (Phoebastria nigripes) and Lysan (Phoebastria immutabilis) Albatross, sooty (Puffinus
griseus), short-tailed (Puffinus tenuirostris) and Buller's (Bulweria bulwerii) and flesh-footed (Puffinus
carneipes) shearwaters are included in this species.
Distribution blocks
It is assumed that this group is distributed in all blocks.
Biomass (B)Biomass of these species in Hunt et al. (2000) is used.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value in the Central Gulf of Alaska Ecopath model described in Ruzicka et al. (2013) is used as nosuch a value is available in our modelled area.
Consumption/biomass ratio (Q/B)
Consumption of these species in Hunt et al. (2000) is divided by the biomass.
Diet compositions
Mean (weighted by biomass) of standardized diet compositions of these species in Hunt et al. (2000) is
used as the basic information. Specific diet compositions based on the information are then assigned basedon the authors’ expert knowledge. The same compositions are assumed in 2013 and 1994.
Catch
There is no catch from 1994 to 2013.

41

16. BLUE SHARK
Species
One species, blue shark (Prionace glauca), is considered.
Distribution blocks
It is assumed that this species is distributed in all blocks.
Biomass (B)Biomass from 1994 to 2012 reported in ISC (2014c) is scaled to our modelled area.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Natural mortality rate and fishing mortality rate reported in ISC (2014c) are used.
Consumption/biomass ratio (Q/B)
The ratio reported in Cox et al. (2002) is used but it is assumed that this species stays in the modelled areafor 180 days.
Diet compositions
Unpublished diet compositions (Ohshimo, unpublished data) are used as the basic information. Specificdiet compositions based on the information are then assigned based on the authors’ expert knowledge. The
same compositions are assumed in 2013 and 1994.
Catch
Catch data used in ISC (2014c) is scaled to our modelled area.
17. MESOPELAGIC SHARKS
Species
Mesopelagic sharks distributed in OYC block such as spiny dogfish (Squalus suckleyi) are assumed in thegroup.
Distribution blocks
It is assumed that this group is distributed in OYC block.
Biomass (B)The value reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The value reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Diet compositions
Diet compositions in Yonezaki et al. (2015) are used as the basic information. Specific diet compositions
based on the information are then assigned based on the authors’ expert knowledge. The same compositions
are assumed in 2013 and 1994.
Catch
Catch of spiny dogfish in 2013 is extracted from catch statistics of offshore bottom trawl fisheries. The
same catch is assumed in 1994.

42

18. TUNAS
Species
Bigeye (Thunnus obesus), yellowfin (Thunnus albacares) and bluefin (Thunnus orientalis) tunas andalbacore (Thunnus alalunga) are included in the group.
Distribution blocks
It is assumed that this group is distributed in all blocks.
Biomass (B)Biomass of bigeye, yellowfin and bluefin tunas and albacore from 1994 to 2012 reported in the references
are scaled to our modelling area (Davies et al., 2014; Harley et al., 2014; ISC, 2014b; d).
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Mean (weighted by biomass) of the values from 1994 to 2013 reported in the references is used (Davies etal., 2014; Harley et al., 2014; ISC, 2014b; d)Consumption/biomass ratio (Q/B)
Mean (weighted by biomass) of the values in the references (Cox et al., 2002; Essington, 2003; Olson andWatters, 2003) is used but it is assumed that these species stay in the modelled area for 180 days.
Diet compositions
Mean (weighted by biomass) diet compositions in Olson and Watters (2003) are used as the basic
information. Specific diet compositions based on the information are then assigned based on the authors’expert knowledge. The same compositions are assumed in 2013 and 1994.
Catch
Catch data used in the references (Davies et al., 2014; Harley et al., 2014; ISC, 2014b; d) are scaled to ourmodelled area.
19. SKIPJACK
Species
One species, skipjack (Katsuwonus pelamis), is considered.
Distribution blocks
It is assumed that this species is distributed in all blocks.
Biomass (B)Biomass from 1994 to 2012 reported in Rice et al. (2014) is scaled to our modelling area.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value reported in Rice et al. (2014) is used.
Consumption/biomass ratio (Q/B)
The value reported in Essington (2003) is used but it is assumed that this species stays in the modelled areafor 180 days.
Diet compositions
Diet compositions in Olson and Watters (2003) are used as the basic information. Specific diet compositions
based on the information are then assigned based on the authors’ expert knowledge. The same compositions
are assumed in 2013 and 1994.

43

CatchCatches used in Rice et al. (2014) are scaled to our modelled area.
20. SWORDFISH
Species
One species, swordfish (Xiphias gladius), is considered.
Distribution blocks
It is assumed that this species is distributed in all blocks.
Biomass (B)Biomass from 2013 reported in ISC (2014a) is scaled to our modelled area. The same value is used in 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value in 2013 reported in ISC (2014a) is used. The same value is used in 1994.
Consumption/biomass ratio (Q/B)
The value reported in Cox et al. (2002) is used but it is assumed that this species stays in the modelled areafor 180 days.
Diet compositions
Diet compositions in Olson and Watters (2003) are used as the basic information. Specific diet compositions
based on the information are then assigned based on the authors’ expert knowledge. The same compositions
are assumed in 2013 and 1994.
Catch
Catch in 2013 used in ISC (2014a) are scaled to our modelled area. The same value is used in 1994.
21. MISCELLANEOUS PISCIVORESSpeciesThough no specific target species is considered, various piscivores such as dolphinfish (Coryphaena
hippurus) and Pacific pomfret (Brama japonica) are assumed to be categorized in the group.
Distribution blocks
It is assumed that this group is distributed in all blocks.
Biomass (B)Biomass is estimated by Ecopath. To estimate the biomass, ecotrophic efficiency (EE) for this group in
Olson and Watters (2003) is used. The same value is used in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value reported in Olson and Watters (2003) is used. The same value is used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The value reported in Olson and Watters (2003) is used. The same value is used in 2013 and 1994.
Diet compositions
Diet compositions are assigned based on the authors’ expert guess. The same compositions are assumed in2013 and 1994.
Catch
No catch is assumed for this group.

4422. JAPANESE SARDINE
Species
One species, Japanese sardine (Sardinops melanostictus), is considered.
Distribution blocks
It is assumed that this species is distributed in all blocks.
Biomass (B)Biomass from 1994 to 2013 reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b)
is increased as the same factor applied to Japanese anchovy (See below).
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b) is used but F isscaled down based on the factor mentioned above..
Consumption/biomass ratio (Q/B)
It is assumed that production and consumption ratio (P/Q) for this species is 0.2. Q/B is calculated in
Ecopath based on other basic input parameters.
Diet compositions
Based on qualitative information in Garrido and Van der Lingen (2014), specific diet compositions are thenassigned based on the authors’ expert knowledge. The same compositions are assumed in 2013 and 1994.
Catch
Catch data reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b) are used.
23. JAPANESE ANCHOVY
Species
One species, Japanese anchovy (Engraulis japonicus), is considered.
Distribution blocks
It is assumed that this species is distributed in all blocks.
Biomass (B)Biomass from 1994 to 2013 reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b)
is estimated by cohort analysis using commercial catch data and an egg production method using asystematic net sampling data set. The estimates of abundance and biomass are only available in the coastal
waters because the cohort analysis and egg production data are restricted to those obtained near coastal
waters. However, biomass estimates in offshore using echosounder data reveal that considerable numberof Japanese anchovy is distributed offshore (Murase et al., 2012). The biomass reported in Fisheries Agency
and Fisheries Research Agency of Japan (2015b) is increased as the factor of biomass reported in Murase
et al. (2012) considering size of the modelling area. The same factor is applied to Japanese sardine andchub and spotted mackerels.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b) is used but F isscaled down based on the factor mentioned above.
Consumption/biomass ratio (Q/B)
It is assumed that production and consumption ratio (P/Q) for this species is 0.2. Q/B is calculated in
Ecopath based on other basic input parameters.

45

Diet compositions
Based on qualitative information in Garrido and Van der Lingen (2014), specific diet compositions are thenassigned based on the authors’ expert knowledge. The same compositions are assumed in 2013 and 1994.
Catch
Catch data reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b) are used.
24. PACIFIC SAURY
Species
One species, Pacific saury (Cololabis saira), is considered.
Distribution blocks
It is assumed that this species is distributed in all blocks.
Biomass (B)Biomass from 2003 to 2013 reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b)
is used.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b) is used.
Consumption/biomass ratio (Q/B)
It is assumed that production and consumption ratio (P/Q) for this species is 0.2. Q/B is calculated in
Ecopath based on other basic input parameters.
Diet compositions
Based on qualitative information in references (Hotta and Odate, 1956; Odate, 1977), specific dietcompositions are then assigned based on the authors’ expert knowledge. The same compositions are
assumed in 2013 and 1994.
Catch
Catches from 1994 to 2013 reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b)
are used.
25. CHUB MACKEREL
Species
One species, chub mackerel (Scomber japonicus), is considered.
Distribution blocks
It is assumed that this species is distributed in all blocks.
Biomass (B)Biomass from 1994 to 2013 reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b)
is increased as the same factor applied to Japanese anchovy (see above).
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b) is used but F isscaled down based on the factor mentioned above..
Consumption/biomass ratio (Q/B)
It is assumed that production and consumption ratio (P/Q) for this species is 0.2. Q/B is calculated in
Ecopath based on other basic input parameters.

46

Diet compositions
Based on information in Nakatsuka et al. (2010), specific diet compositions are then assigned based on theauthors’ expert knowledge. The same compositions are assumed in 2013 and 1994.
Catch
Catch data reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b) are used.
26. SPOTTED MACKEREL
Species
One species, spotted (blue) mackerel (Scomber australasicus; also known as blue mackerel), is considered.
Distribution blocks
It is assumed that this species is distributed in all blocks.
Biomass (B)Biomass from 1995 to 2013 reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b)
is increased as the same factor applied to Japanese anchovy (See abobe).
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b) is used but F isscaled down based on the factor mentioned above..
Consumption/biomass ratio (Q/B)
It is assumed that production and consumption ratio (P/Q) for this species is 0.2. Q/B is calculated in
Ecopath based on other basic input parameters.
Diet compositions
Based on information in Nakatsuka et al. (2010), specific diet compositions are then assigned based on theauthors’ expert knowledge. The same compositions are assumed in 2013 and 1994.
Catch
Catch data reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b) are used.
27. RIGHTEYE FLOUNDERS IN OYC BLOCK
SpeciesSpecies belonging to Pleuronectidae (righteye flounders) distributed in OYC block are included in the group.
Distribution blocks
It is assumed that this group is distributed in OYC block.
Biomass (B)The values reported in Yonezaki et al. (2015) is used in 2013 and 1994. The biomass is doubled to balance
Ecopath.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Mean (weighted by biomass) of the values reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
Mean (weighted by biomass) of the values reported in Yonezaki et al. (2015) is used in 2013 and 1994 .

47

Diet compositions
Mean Diet compositions (weighted by biomass) in Yonezaki et al. (2015) are used as the basic information.
Specific diet compositions based on the information are then assigned based on the authors’ expert
knowledge. The same compositions are assumed in 2013 and 1994.
Catch
Catch of righteye flounders in 2013 is extracted from catch statistics of offshore bottom trawl fisheries. The
same catch is assumed in 1994.
28. ALASKA POLLOCK IN OYC BLOCK
Species
One species, Alaska pollock (Theragra chalcogramma; also known as walleye pollock), is considered.
Distribution blocks
It is assumed that this group is distributed in OYC block.
Biomass (B)The values in 2013 and 1994 reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b)
is used.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The value reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Diet compositions
Diet compositions in Yonezaki et al. (2015) are used as the basic information. Specific diet compositions
based on the information are then assigned based on the authors’ expert knowledge. The same compositions
are assumed in 2013 and 1994.
Catch
Catches reported in Fisheries Agency and Fisheries Research Agency of Japan (2015b) from 1994 to 2013
are used.
29. MISCELLANEOUS BOTTOM FISH IN OYC BLOCK
Species
Bottom fish in OYC block described in Yonezaki et al. (2015) other than righteye flounders and Alaska
pollock are included in the group.
Distribution blocks
It is assumed that this group is distributed in OYC block.
Biomass (B)The values reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Mean (weighted by biomass) of the value reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
Mean (weighted by biomass) of the value reported in Yonezaki et al. (2015) is used in 2013 and 1994.

48

Diet compositions
Mean Diet compositions (weighted by biomass) in Yonezaki et al. (2015) are used as the basic information.
Specific diet compositions based on the information are then assigned based on the authors’ expert
knowledge. The same compositions are assumed in 2013 and 1994.
Catch
Catch of miscellaneous bottom fish in 2013 is extracted from catch statistics of offshore bottom trawl
fisheries. The same catch is assumed in 1994.
30. RIGHTEYE FLOUNDERS IN KC BLOCK
SpeciesSpecies belonging to Pleuronectidae (righteye flounders) distributed in KC block are included in the group.
Distribution blocks
It is assumed that this group is distributed in KC block.
Biomass (B)Biomass is calculated based on catch statistics of offshore bottom trawl fisheries in 2013 assuming harvest
rate = 0.2. The same value is used in 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The same values for righteye flounders in OYC block is used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The same values for righteye flounders in OYC block is used in 2013 and 1994.
Diet compositions
Mean Diet compositions (weighted by biomass) for righteye flounders in OYC block in Yonezaki et al.
(2015) are used as the basic information. Specific diet compositions based on the information are thenassigned based on the authors’ expert knowledge. The same compositions are assumed in 2013 and 1994.
Catch
Catch of righteye flounders in KC block in 2013 is extracted from catch statistics of offshore bottom trawl
fisheries. The same catch is assumed in 1994.
31. SEABREAMS
Species
Seabreams and seabream-like species (e.g. Pagrus major, red seabream) are included in the group.
Distribution blocks
It is assumed that this group is distributed in KC block.
Biomass (B)Biomass is calculated based on catch statistics of offshore bottom trawl fisheries in 2013 assuming harvest
rate = 0.2. The same value is used in 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
M and F of red seabream for 2012 reported in Fisheries Agency and Fisheries Research Agency of Japan(2015b) are used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
Consumption/biomass ratio (Q/B) is assumed as 0.2 of P/B.

49

Diet compositions
Based on qualitative information in Fisheries Agency and Fisheries Research Agency of Japan (2015b),
specific diet compositions are then assigned based on the authors’ expert knowledge. The same
compositions are assumed in 2013 and 1994.
Catch
Catch of seabreams in KC block in 2013 is extracted from catch statistics of offshore bottom trawl fisheries.
The same catch is assumed in 1994.
32. MISCELLANEOUS BOTTOM FISH IN KC BLOCK
Species
Bottom fish other than righteye flounders and seabreams in KC block recorded in catch statistics of offshore
bottom trawl fisheries are included in the group.
Distribution blocks
It is assumed that this group is distributed in KC block.
Biomass (B)Biomass is calculated based on catch statistics of offshore bottom trawl fisheries in 2013 assuming harvest
rate = 0.2. The same value is used in 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The same value for miscellaneous bottom fish in OYC block is used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The same value for miscellaneous bottom fish in OYC block is used in 2013 and 1994.
Diet compositions
The same diet compositions of miscellaneous bottom fish in OYC block are used but they are adjusted
based on the authors’ expert knowledge. The same compositions are assumed in 2013 and 1994.
Catch
Catch of miscellaneous bottom fish in 2013 is extracted from catch statistics of offshore bottom trawl
fisheries. The same catch is assumed in 1994.
33. MESOPELAGIC FISH IN OYC BLOCK
SpeciesThough no specific target species is considered, various myctophids are assumed to be categorized in thegroup.
Distribution blocks
It is assumed that this group is distributed in OYC block.
Biomass (B)Biomass is estimated by Ecopath. To estimate the biomass, ecotrophic efficiency (EE) for this group in
Yonezaki et al. (2015) is used. The same value is used in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The value reported in Yonezaki et al. (2015) is used in 2013 and 1994.

50

Diet compositions
Diet compositions in Yonezaki et al. (2015) are used as the basic information. Specific diet compositions
based on the information are then assigned based on the authors’ expert knowledge. The same compositions
are assumed in 2013 and 1994.
Catch
No catch is assumed for this group.
34. MESOPELAGIC FISH IN KC BLOCK
SpeciesThough no specific target species is considered, various myctophids are assumed to be categorized in thegroup.
Distribution blocks
It is assumed that this group is distributed in KC block.
Biomass (B)Biomass is estimated by Ecopath. To estimate the biomass, ecotrophic efficiency (EE) for this group in
Yonezaki et al. (2015) is used. The same value is used in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The value reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Diet compositions
Diet compositions in Yonezaki et al. (2015) are used as the basic information. Specific diet compositions
based on the information are then assigned based on the authors’ expert knowledge. The same compositions
are assumed in 2013 and 1994.
Catch
No catch is assumed for this group.

35. MESOPELAGIC FISH IN OF BLOCK
SpeciesThough no specific target species is considered, various myctophids are assumed to be categorized in thegroup.
Distribution blocks
It is assumed that this group is distributed in OF block.
Biomass (B)Biomass is estimated by Ecopath. To estimate the biomass, ecotrophic efficiency (EE) for this group in
Yonezaki et al. (2015) is used. The same value is used in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The value reported in Yonezaki et al. (2015) is used in 2013 and 1994.
51

Diet compositions
Diet compositions in Yonezaki et al. (2015) are used as the basic information. Specific diet compositions
based on the information are then assigned based on the authors’ expert knowledge. The same compositions
are assumed in 2013 and 1994.
Catch
No catch is assumed for this group.
36. SURFACE CEPHALOPODS
SpeciesThough no specific target species is considered, surface squids, such as Japanese flying squid (Todarodes
pacificus) and spear squid (Heterololigo bleekeri) are assumed to be categorized in the group.
Distribution blocks
It is assumed that this group is distributed in all blocks.
Biomass (B)Biomass is estimated by Ecopath. To estimate the biomass, ecotrophic efficiency (EE) for the two species
in Yonezaki et al. (2015) is used. Mean (weighted by biomass) of the values is calculated. The same value
is used in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Mean (weighted by biomass) of the values of the two species reported in Yonezaki et al. (2015) is used in2013 and 1994.
Consumption/biomass ratio (Q/B)
Mean (weighted by biomass) of the values of the two species reported in Yonezaki et al. (2015) is used in2013 and 1994.
Diet compositions
Mean (weighted by biomass) diet compositions of the two species in Yonezaki et al. (2015) are used as thebasic information. Specific diet compositions based on the information are then assigned based on theauthors’ expert knowledge. The same compositions are assumed in 2013 and 1994.
Catch
Catch of Japanese flying squid in 2013 reported in Fisheries Agency and Fisheries Research Agency ofJapan (2015b) is used. Same value is used in 1994.
37. MESOPELAGIC CEPHALOPODS
Species
Various mesopelagic cephalopods are assumed to be categorized in the group.
Distribution blocks
It is assumed that this group is distributed in all blocks.
Biomass (B)Biomass is estimated by Ecopath. To estimate the biomass, ecotrophic efficiency (EE) fromesopelagic
cephalopods in Yonezaki et al. (2015) is used. Mean (weighted by biomass) of the values is calculated. The
same value is used in 2013 and 1994.

52

Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Mean (weighted by biomass) of the values of the mesopelagic cephalopods reported in Yonezaki et al.
(2015) is used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
Mean (weighted by biomass) of the values of mesopelagic cephalopods reported in Yonezaki et al. (2015)is used in 2013 and 1994.
Diet compositions
Mean (weighted by biomass) diet compositions of the mesopelagic cephalopods in Yonezaki et al. (2015)
are used as the basic information. Specific diet compositions based on the information are then assigned
based on the authors’ expert knowledge. The same compositions are assumed in 2013 and 1994.
Catch
No catch is assumed for this group.
38. BENTHOS IN OYC BLOCK
SpeciesThough no specific target species is considered, crabs, shrimps and macrobenthos are assumed to be
categorized in the group.
Distribution blocks
It is assumed that this group is distributed in OYC block.
Biomass (B)Biomass of benthos in Yonezaki et al. (2015) is used. The same value is used in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Mean (weighted by biomass) of the values of the benthos reported in Yonezaki et al. (2015) is used in 2013
and 1994.
Consumption/biomass ratio (Q/B)
Mean (weighted by biomass) of the values of benthos reported in Yonezaki et al. (2015) is used in 2013
and 1994.
Diet compositions
Mean (weighted by biomass) diet compositions of the benthos in Yonezaki et al. (2015) are used as thebasic information. Specific diet compositions based on the information are then assigned based on theauthors’ expert knowledge. The same compositions are assumed in 2013 and 1994.
Catch
Catch of crabs in 2013 is extracted from catch statistics of offshore bottom trawl fisheries. The same catchis assumed in 1994.
39. BENTHOS IN KC BLOCK
SpeciesThough no specific target species is considered, shrimps and macrobenthos are assumed to be categorized
in the group.
Distribution blocks
It is assumed that this group is distributed in KC block.

53

Biomass (B)Biomass is estimated by Ecopath. To estimate the biomass, mean (weighted by biomass) of ecotrophic
efficiency (EE) for benthos in Yonezaki et al. (2015) is used. The same value is used in 2013 and 1994.

Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Mean (weighted by biomass) of the values of the benthos reported in Yonezaki et al. (2015) is used in 2013
and 1994.
Consumption/biomass ratio (Q/B)
Mean (weighted by biomass) of the values of benthos reported in Yonezaki et al. (2015) is used in 2013
and 1994.
Diet compositions
Mean (weighted by biomass) diet compositions of the benthos in Yonezaki et al. (2015) are used as thebasic information. Specific diet compositions based on the information are then assigned based on theauthors’ expert knowledge. The same compositions are assumed in 2013 and 1994.
Catch
Catch of shrimps in 2013 is extracted from catch statistics of offshore bottom trawl fisheries. The samecatch is assumed in 1994.
40. KRILL IN OYC BLOCK
SpeciesSpecies belonging to Euphausiidae (krill) are assumed to be categorized in the group.
Distribution blocks
It is assumed that this group is distributed in OYC block.
Biomass (B)Mean biomass around OYC block estimated by Murase et al. (2007) is used. The same value is used in2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The value reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Diet compositions
Diet compositions in Yonezaki et al. (2015) are used as the basic information. Specific diet compositions
based on the information are then assigned based on the authors’ expert knowledge. The same compositions
are assumed in 2013 and 1994.
Catch
Catch of Euphausia pacifica in 2013 is extracted from catch statistics. The same catch is assumed in 1994.
41. KRILL IN OF BLOCK
SpeciesSpecies belonging to Euphausiidae (krill) are assumed to be categorized in the group.

54

Distribution blocks
It is assumed that this group is distributed in OF block.
Biomass (B)Minimum biomass in OF block estimated by Murase et al. (2007) is used. The same value is used in 2013
and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The value reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Diet compositions
Diet compositions in Yonezaki et al. (2015) are used as the basic information. Specific diet compositions
based on the information are then assigned based on the authors’ expert knowledge. The same compositions
are assumed in 2013 and 1994.
Catch
No catch is assumed for this group.
42. ZOOPLANKTON IN OYC BLOCK
SpeciesThough no specific target species is considered, various planktons such as copepods and chaetognaths are
assumed to be categorized in the group.
Distribution blocks
It is assumed that this group is distributed in OYC block.
Biomass (B)Mean biomass from 1994 to 2013 is calculated using NORPAC (North Pacific standard net) data (Takasuka,
unpublished data). The biomass is doubled to balance Ecopath in 2013 and 1994.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value of copepods reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The value of copepods reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Diet compositions
Diet compositions of copepods in Yonezaki et al. (2015) are used as the basic information. Specific dietcompositions based on the information are then assigned based on the authors’ expert knowledge. The same
compositions are assumed in 2013 and 1994.
Catch
No catch is assumed for this group.
43. ZOOPLANKTON IN KC BLOCK
SpeciesThough no specific target species is considered, various planktons such as copepods and chaetognaths are
assumed to be categorized in the group.

55

Distribution blocks
It is assumed that this group is distributed in KC block.
Biomass (B)Mean biomass from 1994 to 2013 is calculated using NORPAC (North Pacific standard net) data (Takasuka,
unpublished data).
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value of copepods reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The value of copepods reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Diet compositions
Diet compositions of copepods in Yonezaki et al. (2015) are used as the basic information. Specific dietcompositions based on the information are then assigned based on the authors’ expert knowledge. The same
compositions are assumed in 2013 and 1994.
Catch
No catch is assumed for this group.
44. ZOOPLANKTON IN OF BLOCK
SpeciesThough no specific target species is considered, various planktons such as copepods and chaetognaths are
assumed to be categorized in the group.
Distribution blocks
It is assumed that this group is distributed in OF block.
Biomass (B)A mean biomass in the block is calculated using all NORPAC (North Pacific standard net) data from 1978
to 2013 as sampling coverage is not sufficient (Takasuka, unpublished data).
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The value of copepods reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Consumption/biomass ratio (Q/B)
The value of copepods reported in Yonezaki et al. (2015) is used in 2013 and 1994.
Diet compositions
Diet compositions of copepods in Yonezaki et al. (2015) are used as the basic information. Specific dietcompositions based on the information are then assigned based on the authors’ expert knowledge. The same
compositions are assumed in 2013 and 1994.
Catch
No catch is assumed for this group.
45. PHYTOPLANKTON IN OYC BLOCK
Species
No s species is assumed.

56

Distribution blocks
It is assumed that this group is distributed in OYC block.
Biomass (B)Annual means of chlorophyll-a volume concentrations (mg/m3) from 2003 to 2013 obtained by Moderate
Resolution Imaging Spectroradiometer aboard the Aqua satellite (Aqua MODIS) are firstly converted tosurface concentrations (mg/m2) based on Morel and Berthon (1989). The surface chlorophyll-aconcentrations are multiplied by a conversation factor, 400, described in Link et al. (2006) to convert towet weight (mg/ m2).
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Annual means of primary production around OYC block (Kameda, unpublished data) are used as P.
Consumption/biomass ratio (Q/B)
Not applicable.
Diet compositions
Not applicable.
Catch
No catch is assumed for this group.
46. PHYTOPLANKTON IN KC BLOCK
Species
No species is assumed.
Distribution blocks
It is assumed that this group is distributed in KC block.
Biomass (B)Annual means of chlorophyll-a volume concentrations (mg/m3) from 2003 to 2013 obtained by Moderate
Resolution Imaging Spectroradiometer aboard the Aqua satellite (Aqua MODIS) are firstly converted tosurface concentrations (mg/m2) based on Morel and Berthon (1989). The surface chlorophyll-aconcentrations are multiplied by a conversation factor, 400, described in Link et al. (2006) to convert towet weight (mg/ m2).
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Annual means of primary production around KC block (Kameda, unpublished data) are used as P.
Consumption/biomass ratio (Q/B)
Not applicable.
Diet compositions
Not applicable.
Catch
No catch is assumed for this group.
47. PHYTOPLANKTON IN OF BLOCK
Species
No species is assumed.

57

Distribution blocks
It is assumed that this group is distributed in KC block.
Biomass (B)Annual means of chlorophyll-a volume concentrations (mg/m3) from 2003 to 2013 obtained by Moderate
Resolution Imaging Spectroradiometer aboard the Aqua satellite (Aqua MODIS) are firstly converted tosurface concentrations (mg/m2) based on Morel and Berthon (1989). The surface chlorophyll-aconcentrations are multiplied by a conversation factor, 400, described in Link et al. (2006) to convert towet weight (mg/ m2).
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
The same Annual means of primary production in OYC block are used as P.
Consumption/biomass ratio (Q/B)
Not applicable.
Diet compositions
Not applicable.
Catch
No catch is assumed for this group.
48. DETRITUS IN OYC BLCOK
Species
Not applicable.
Distribution blocks
It is assumed that this group is distributed in OYC block.
Biomass (B)Biomass is calculated based on Pauly et al. (1993) using phytoplankton data in the block.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Not applicable.
Consumption/biomass ratio (Q/B)
Not applicable.
Diet compositions
Not applicable.
Catch
No catch is assumed for this group.
49. DETRITUS IN KC BLOCK
Species
Not applicable.
Distribution blocks
It is assumed that this group is distributed in KC block.

58

Biomass (B)Biomass is calculated based on Pauly et al. (1993) using phytoplankton data in the block.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Not applicable.
Consumption/biomass ratio (Q/B)
Not applicable.
Diet compositions
Not applicable.
Catch
No catch is assumed for this group.
50. DETRITUS IN OF BLOCK
Species
Not applicable.
Distribution blocks
It is assumed that this group is distributed in OF block.
Biomass (B)Biomass is calculated based on Pauly et al. (1993) using phytoplankton data in the block.
Production/biomass ratio (P/B) or total mortality (Z; natural mortality rate, M, plus fishingmortality rate, F)
Not applicable.
Consumption/biomass ratio (Q/B)
Not applicable.
Diet compositions
Not applicable.
Catch
No catch is assumed for this group.
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Ruzicka, J.J., Steele, J.H., Ballerini, T., Gaichas, S.K. and Ainley, D.G. 2013. Dividing up the pie: Whales, fish, and humans ascompetitors. Prog. Oceanogr. 116: 207-19.
Sigurjonsson, J. and Vikingsson, G.A. 1997. Seasonal abundance of and estimated food consumption by cetaceans in Icelandic andadjacent waters. J. North. Atl. Fish. Sci. 22: 271-87.
Tamura, T., Konishi, K. and Isoda, T. 2016. Updated estimation of prey consumption by sei, Bryde's and common minke whales in
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Trites, A.W. and Pauly, D. 1998. Estimating mean body masses of marine mammals from maximum body lengths. Canadian Journalof Zoology 76: 886-96.
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61

Appendix 2
Results of pre-balance diagnostics for Ecopath in 2013
based on Link (2010)
This is Appendix 2 of “SC/F16/JR28. Murase, H., Tamura, T., Hakamada, T., Watari, S., Okazaki, M., Kiyofuji,
H, Yonezaki, S and Kitakado, T. 2015 Ecosystem modelling in the western North Pacific from 1994 to 2013 using
Ecopath with Ecosim (EwE): some preliminary results. Paper SC/F16/JR28 presented to the JARPNII special
permit expert panel review workshop, Tokyo, February 2016 (unpublished)”.
Table A2-1. Summary of results of pre-balance diagnostics for Ecopath in in the western North Pacific in 2013
based on Link (2010).The diagnostics are based on the authors’ judgment.
Diagnostic criterion

Results

Class of diagnostic: Biomasses across taxa/TLs
1
Biomass should span 5–7 orders of magnitude2
Slope (on log scale) should be ∼5–10% decline
3
Taxa notably above or below slope-line may need more attention
Class of diagnostic: Biomass ratios
4Compared across taxa, predators biomass should be less than that of (1 relative to) their prey5
Number of zeroes indicates potential trophic difference between predators and prey
6Compared across taxa, ratios indicate major pathways of trophic flows (e.g. benthic vs pelagic)
Class of diagnostic: Vital rates across taxa/TLs
7
Normal biomass decomposition of C/B, P/B and R/B (exception for homeotherms at upper TLs)
8
Taxa notably above or below trend merit further attention
Class of diagnostic: Vital rate ratios
9Compared across taxa, predators' C/B, P/B and R/B should be less than 1 relative to their prey10
Number of zeroes indicates potential trophic difference between predators and prey
11
P and B relative to PP approximate TL
12Compared across vital rates; P/Cs or P/Rs near 1 merit reevaluating
Class of diagnostic: Total production and removals
13
Total, scaled values of P, C and R should again follow a decomposition with increasing TL
14Consumption of a taxa should be less than production by that taxa
15
Consumption by a taxa should be more than production by that taxa
16
Total human removals should be less than total production of a taxa
17
Total human removals should be compared to consumption of a taxa

Fig.A2-1

Good

Diagnostics
Acceptable

Cautionxxxx

TableA2-2xxxx

Fig.A2-2xx

TableA2-3
Fig.A2-3
Fig.A2-4xxx

Fig.A2-5

Fig.A2-6xxxx

Table A2-2. Biomass ratio which are corresponding to the diagnostic criterions 4-5 in Table A2-1. PP: primary
producers, ZP: zooplankton and HMF: highly migratory fish.
Pelagic/mesopelagics:PP
ZP:PP
Pelagic/mesopelagics:ZP
Baleen whales:ZP
Demersal:Pelagic/mesopelagics
HMF:Pelagic/mesopelagics
Toothed whales:Pelagic/mesopelagics

Biomass
ratio
0.901
4.204
0.214
0.005
0.082
0.127
0.019

Pelagic fish:all fish
Mesopelagic gish:all fish
Demersal fish:all fish
HMF: all fish

0.368
0.426
0.081
0.124

TL4:<TL3

0.02425

Prey/Predator

Table A2-3. Vital rate ratio which are corresponding to the diagnostic criterions 9-10 in Table A2-1. PP: primary
producers, ZP: zooplankton and HMF: highly migratory fish.
Prey/predator
Pelagic/mesopelagics:ZP
ZP:PP
Pelagic/mesopelagics:PP
Demersal:Pelagic/mesopelagics
HMF:Pelagic/mesopelagics
Toothed whales:Pelagic/mesopelagics
Baleen whales:ZP

62

C/B
0.287
0.453
0.797
1.380
0.226

P/B
0.158
0.059
0.009
0.352
0.298
0.053
0.008

R/B
0.214
4.134
0.559
0.930
0.102

Fig. A2-1. Trophic decomposition (trend line), showing variously declining levels of biomass with increasing
trophic level (log scale). Trophic level increases from right to left. OYC: coastal Oyashio block, KC: coastal
Kuroshio block and OF: offshore block. This figure corresponds to the diagnostic criterions 1-3 in Table A2-1.

Fig. A2-2. Vital rates (log scale) that expresses trophic decomposition (trend line) with the exception of
consumption and respiration for homeotherms. Trophic level increases from left to right. OYC: coastal Oyashio
block, KC: coastal Kuroshio block and OF: offshore block. This figure corresponds to the diagnostic criterions 78 in Table A2-1.

63

Fig. A2-3. Vital rate ratios (log scale), as compared to the primary producers. Trophic level increases from rightto left. OYC: coastal Oyashio block, KC: coastal Kuroshio block and OF: offshore block. This figure corresponds
to the diagnostic criterion 11 in Table A2-1.

Fig. A2-4. Vital rate ratios, as compared across rates for each taxa. Trophic level increases from right to left. OYC:
coastal Oyashio block, KC: coastal Kuroshio block and OF: offshore block. This figure corresponds to thediagnostic criterion 12 in Table A2-1.

64

Fig. A2-5. Total production and removals, scaled to the full ecosystem, comparing internal flows. Trophic level
increases from right to left. OYC: coastal Oyashio block, KC: coastal Kuroshio block and OF: offshore block. This
figure corresponds to the diagnostic criterions 13-15 in Table A2-1.

Fig. A2-6. Flows relative to external removals. Trophic level increases from right to left. OYC: coastal Oyashio
block, KC: coastal Kuroshio block and OF: offshore block. This figure corresponds to the diagnostic criterions 1617 in Table A2-1.
REFERENCES
Link, J.S. 2010. Adding rigor to ecological network models by evaluating a set of pre-balance diagnostics: A plea for PREBAL. Ecol. Model.
221: 1580-91.

65Appendix 3
Results of pre-balance diagnostics for Ecopath in 1994
based on Link (2010)
This is Appendix 3 of “SC/F16/JR28. Murase, H., Tamura, T., Hakamada, T., Watari, S., Okazaki, M., Kiyofuji,
H, Yonezaki, S and Kitakado, T. 2015 Ecosystem modelling in the western North Pacific from 1994 to 2013 using
Ecopath with Ecosim (EwE): some preliminary results. Paper SC/F16/JR28 presented to the JARPNII special
permit expert panel review workshop, Tokyo, February 2016 (unpublished)”.
Table A3-1. Summary of results of pre-balance diagnostics for Ecopath in in the western North Pacific in 2013
based on Link (2010). The diagnostics are based on the authors’ judgment.
Diagnostic criterion

Results

Class of diagnostic: Biomasses across taxa/TLs
1
Biomass should span 5–7 orders of magnitude2
Slope (on log scale) should be ∼5–10% decline
3
Taxa notably above or below slope-line may need more attention
Class of diagnostic: Biomass ratios
4Compared across taxa, predators biomass should be less than that of (1 relative to) their prey5
Number of zeroes indicates potential trophic difference between predators and prey
6Compared across taxa, ratios indicate major pathways of trophic flows (e.g. benthic vs pelagic)
Class of diagnostic: Vital rates across taxa/TLs
7
Normal biomass decomposition of C/B, P/B and R/B (exception for homeotherms at upper TLs)
8
Taxa notably above or below trend merit further attention
Class of diagnostic: Vital rate ratios
9Compared across taxa, predators' C/B, P/B and R/B should be less than 1 relative to their prey10
Number of zeroes indicates potential trophic difference between predators and prey
11
P and B relative to PP approximate TL
12Compared across vital rates; P/Cs or P/Rs near 1 merit reevaluating
Class of diagnostic: Total production and removals
13
Total, scaled values of P, C and R should again follow a decomposition with increasing TL
14Consumption of a taxa should be less than production by that taxa
15
Consumption by a taxa should be more than production by that taxa
16
Total human removals should be less than total production of a taxa
17
Total human removals should be compared to consumption of a taxa

Fig.A3-1

Good

Diagnostics
Acceptable

Cautionxxxx

TableA3-2xxxx

Fig.A3-2xx

TableA3-3
Fig.A3-3
Fig.A3-4xxx

Fig.A3-5

Fig.A3-6xxxx

Table A3-2. Biomass ratio which are corresponding to the diagnostic criterions 4-5 in Table A3-1. PP: primary
producers, ZP: zooplankton and HMF: highly migratory fish.
Pelagic/mesopelagics:PP
ZP:PP
Pelagic/mesopelagics:ZP
Baleen whales:ZP
Demersal:Pelagic/mesopelagics
HMF:Pelagic/mesopelagics
Toothed whales:Pelagic/mesopelagics

Biomass
ratio
0.872
4.173
0.209
0.004
0.125
0.021
0.021

Pelagic fish:all fish
Mesopelagic gish:all fish
Demersal fish:all fish
HMF: all fish

0.472
0.381
0.119
0.02

TL4:<TL3

0.007

Prey/Predator

Table A3-3. Vital rate ratio which are corresponding to the diagnostic criterions 9-10 in Table A3-1. PP: primary
producers, ZP: zooplankton and HMF: highly migratory fish.
Prey/predator
Pelagic/mesopelagics:ZP
ZP:PP
Pelagic/mesopelagics:PP
Demersal:Pelagic/mesopelagics
HMF:Pelagic/mesopelagics
Toothed whales:Pelagic/mesopelagics
Baleen whales:ZP

66

C/B
0.290

1.540
0.956
1.379
0.232

P/B
0.162
0.059
0.010
2.071
0.366
0.054
0.008

R/B
0.418

1.335
1.184
1.892
0.455

Fig. A3-1. Trophic decomposition (trend line), showing variously declining levels of biomass with increasing
trophic level (log scale). Trophic level increases from right to left. OYC: coastal Oyashio block, KC: coastal
Kuroshio block and OF: offshore block. This figure corresponds to the diagnostic criterions 1-3 in Table A3-1.

Fig. A3-2. Vital rates (log scale) that expresses trophic decomposition (trend line) with the exception of
consumption and respiration for homeotherms. Trophic level increases from left to right. OYC: coastal Oyashio
block, KC: coastal Kuroshio block and OF: offshore block. This figure corresponds to the diagnostic criterions 78 in Table A3-1.

67

Fig. A3-3. Vital rate ratios (log scale), as compared to the primary producers. Trophic level increases from rightto left. OYC: coastal Oyashio block, KC: coastal Kuroshio block and OF: offshore block. This figure corresponds
to the diagnostic criterion 11 in Table A3-1.

Fig. A3-4. Vital rate ratios, as compared across rates for each taxa. Trophic level increases from right to left. OYC:
coastal Oyashio block, KC: coastal Kuroshio block and OF: offshore block. This figure corresponds to thediagnostic criterion 12 in Table A3-1.

68

Fig. A3-5. Total production and removals, scaled to the full ecosystem, comparing internal flows. Trophic level
increases from right to left. OYC: coastal Oyashio block, KC: coastal Kuroshio block and OF: offshore block. This
figure corresponds to the diagnostic criterions 13-15 in Table A3-1.

Fig. A3-6. Flows relative to external removals. Trophic level increases from right to left. OYC: coastal Oyashio
block, KC: coastal Kuroshio block and OF: offshore block. This figure corresponds to the diagnostic criterions 1617 in Table A3-1.
REFERENCES
Link, J.S. 2010. Adding rigor to ecological network models by evaluating a set of pre-balance diagnostics: A plea for PREBAL. Ecol. Model.
221: 1580-91.

69