1 Factors Affecting the Efficiency of Tuna Fishing Vessels: Implications on Tuna Production Pedro A. Alviola IV* Associate Professor, School of Management University of the Philippines Mindanao Mintal, Davao City, Philippines Adjunct Faculty, University of Arkansas [email protected]Jon Marx P. Sarmiento Assistant Professor, School of Management University of the Philippines Mindanao Mintal, Davao City, Philippines [email protected]Larry N. Digal Professor, School of Management University of the Philippines Mindanao Mintal, Davao City, Philippines [email protected]Sherleen M. Comidoy School of Management University of the Philippines Mindanao Mintal, Davao City, Philippines [email protected]_____________________ * Corresponding Author: Pedro A. Alviola IV, PhD, School of Management University of the Philippines Mindanao, Mintal, Davao City, Philippines, 8022, Telefax: +6382 295 2750 [email protected]
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Factors Affecting the Efficiency of Tuna Fishing Vessels: Implications on Tuna Production and Improvement
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Factors Affecting the Efficiency of Tuna Fishing Vessels:
The Cobb-Douglas model in equation 1 specifies the input drivers of catch output2 such as gross
registered tonnage (GRT), effort in days (Eff), fuel and water consumption (Fuel and Water)
while the Translog specification (equation 2) in addition includes the square and interaction
terms of the inputs3. The terms �� !and ��! represent the random error and error associated with
technical inefficiency while *�!is the unobservable random variable in the technical inefficiency
effects model. The sources of technical inefficiency ��! in equation 3 include berthing days,
harbor and market type, fishing period and fishing grounds (Table 1). The technical inefficiency
term is measured through the error terms, and can be decomposed into statistical noise and
factors associated with inefficiency (Bakhsh, 2007).
2 We follow del Hoyo et al. (2004) and Esmaeili (2006) approach in measuring catch output, where the former
measures total volume in tonnes while the latter in kilograms. 3 While multicollinearity is expected among the independent drivers of catch output, a variance inflation factor
(VIF) benchmark value that is less than 10 imply that there is no degrading multicollinearity present. In this study,
the VIF among the explanatory variables were less than 10, (GRT :1.33, Effort :1.80, Fuel :2.61 and Water :2.14),
thus no degrading multicollinearity was observed.
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In this paper, we estimated the stochastic production function and technical inefficiency
equations using maximum likelihood estimation with the one-stage approach (Battese and Coelli,
1995). We used the FRONTIER (v.4.1) program developed by Coelli (1996) to estimate
equations 1-3 and performed the likelihood-ratio test of different null hypotheses in order to
identify the model that best fits the data. In addition, we obtained the critical values from the
mixed chi-squared distribution (Kodde and Palm, 1986) and calculated the test statistic using the
formula found in the paper of New (2012).
7� = !−2{ln [<=>?@
<!=>A@]} = !−2{ln[7=0@] − ln![7=0�@]} (4)
RESULTS AND DISCUSSION
Model Inference
The first hypothesis test verifies the assumption of exhibiting a half-normal distribution
(Coelli, 1996) or equivalently determining the absence of the constant term in the inefficiency
model (δ0=0). From Table 2, both the Cobb-Douglas and Translog specifications have likelihood
ratio (LR) statistics less than the critical values (0.21,-0.62 < 5.41). Thus, the assumption of
half-normal distribution was not rejected. Likewise, the two specifications were subjected to the
second hypothesis test of determining whether ɣ = 0. This involved examining the restriction on
variance parameter gamma, or equivalently testing the the absence of the technical inefficiency
effects by comparing the Ordinary Least Squares (OLS) and Maximum Likelihood Estimator
(MLE) estimates. In the Cobb-Douglas specification, the LR statistic was greater than the critical
value (30.58 > 27.03), thereby rejecting the null hypothesis whereas in the Translog model, we
failed to reject the null hypothesis (16.67 < 27.03). Therefore in this model, the OLS estimates
were preferred over those generated by the MLE procedure.
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Finally, we assumed the absence of squared and interaction terms and carried the
comparative test between Translog and Cobb-Douglas models. With the null hypothesis
validating the choice of the Cobb-Douglas function (-9.11 < 10.50), the final model resulted in a
Cobb-Douglas specification that contained the sources of inefficiency but lacked the constant
term in the inefficiency model. Also, we utilized the stochastic frontier production’s variance
parameters, gamma and sigma squared to validate the functional form of the model. The gamma
parameter represents the proportion of the composite error term characterised by the technical
inefficiency (New, 2012). From table 3, following Taru et al. (2011) paper, 74% of the variation
in the fishing vessels’ output levels was due to technical inefficiency. The model has a sigma-
squared value of 0.39 and is statistically significant at 1 percent level (Table 3).
Also from table 3, the estimated coefficients for each input in the Cobb-Douglas
specification were considered in the constant elasticity of the input. The model results suggest
that increasing the vessel size by 10 percent in terms of GRT, increases output by approximately
5.2 percent. Likewise, a 10 percent increase in fuel consumption and effort days increases output
by 3.9 percent and 2.5 percent, respectively. Also, if water consumption increases by 10 percent,
then output will increase approximately by 0.8 percent. Also, we observe the diminishing returns
to scale in the Cobb-Douglas function. Finally, inputs that significanly drive output responsivess
are vessel size, fuel consumption, effort days and water consumption in decreasing order.
Technical Efficiency Performance
The technical efficiency score for the sample vessels ranged from 0.12 to 0.95 with 0.79
as the mean value (Figure 1). The majority of the vessels (41.5%) had technical efficiency
indices greater than or equal to 0.9, while 29% belong to 0.8-0.9 indices and 12% into the indices
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equal to 0.7-0.8. This suggests that in 2012, almost half of the tuna fishing vessels in General
Santos City, operated close to the efficient frontier and only 10% performed below the 0.50
index level. In terms of GRT classification, vessels with less than 50 GRT had an average
technical efficiency score of 0.82, while vessels with GRT of 50 to 100 garnered an efficiency
score of 0.73. However, for vessels with above 100 GRT, the average score efficiency score was
lowest at 0.71. From the sample, the results indicate that larger vessels are less technically
efficient compared to smaller vessels.The presence of technical inefficiency is verified because
the gamma term is statistically significant. From the model, variables such as berthing days,
harbors and markets 1 and 3, and 1st quarter fishing period were significant at α=0.05 level of
significance (Table 5). In this case, a positive coefficient indicates diminishing technical
efficiency while negative values represent effciency improvements.
Berthing Days
The average tuna fishing vessel’s unloading period (days) showed a significant negative
relationship with technical inefficiency (positive relationship to technical efficiency). This
implies that increasing the berthing period by one day increases technical efficiency (decreases
technical inefficiency) by approximately 3%. This is possible because the longer the vessel’s
berthing days implies longer time to unload catches because of higher volume harvested.
Furthermore, longer berthing days would translate to relatively lower operational cost on a per
vessel basis. Tuna fishing vessels with berthing periods exceeding 10 days had an average
technical score of 0.93 while those with 5 to 10 days and less than 5 berthing days had lower
technical efficiency scores equal to 0.84 and 0.78 respectively. This is because when berthing
days are prolonged, input consumption of water and fuel become minimal. Furthermore, vessels
with more than 10 berthing days had the lowest input consumption per tonnage for water and
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fuel (0.28 and 13.91) but incurred the highest level of output per trip for the year 2012 (14 t)
(Table 4).
Harbors and Markets
The fishing port complex of General Santos City contains four harbors and two wharves.
Each harbor corresponds to the type of fishing vessel and tuna markets. Harbors and markets 1 to
3 and wharf 1 cater domestic fishing vessels while harbor and market 4 and wharf 2 accomodate
foreign operators. In this study, we consider the first three harbors and markets to be relevant.
We found using field observations and key informant interviews that harbor 1 deals with
handline tuna fishermen while harbors 2 and 3 transact with purse-seiners and mini purse seiners
or ring netters. Furthermore, harbor 1 is used for market transactions that involve export and
domestic market of Grade A whole, frozen and chilled yellowfin tuna and by products such as
blue marlin (market 1). On the other hand, market 2 deals with assorted fish types for the
domestic market while market 3 process tunas that are usually purchased by canning companies
such as skipjack.
The Cobb-Douglas technical inefficiency model suggests that fishing vessels that unload
in harbor and market 1 display a positive relationship with technical efficiency. This means that
handliners are more technically efficient compared to other tuna fishing vessels that discharge in
harbors and markets 2 and 3. In 2012, the average handline fishing vessel holds a gross tonnage
size of 15 GRT and usually unloads majority (84%) of its catch in harbor and market 1 (Table 5).
Also, the data indicate that the average handline vessel’s fuel consumption was 784 liters for 16
days of operation and unloaded its catch for two mooring days. In terms of gross tonnage, the
fuel consumption of handliners appear to be higher, but the daily fuel consumption was lower by
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49 liters per day compared to 77 liters and 82 liters for vessels unloading in harbors and markets
2 and 3 respectively. The berthing days were also shorter for handline tuna fishing vessels
because of frequent yearly trips. Also, the technical efficiency of tuna handliners is driven in
part by the usage of fish aggregating devices (FAD)4 or payaos, because handliners share the
technology with tuna purse seiners which target small pelagic tuna species such as skipjack. For
example, Aprieto (1995) found that this technology sharing enabled handline fishermen monitor
fish concentrations and guard fish clusters from intruders. In this manner, handliners can easily
catch tuna species such as yellowfin and bigeye because these are usually found at the bottom of
skipjack schools. Also, this arrangement enables handliners to generate capital savings from
purchasing additional aggregating devices.
The inefficiency model further suggests that tuna fishing vessels that unload in harbor
and market 3 are relatively technically inefficient (0.74 technical efficiency score) compared to
handline fishing vessels. An average purse seine vessel’s capacity is 88.5 GRT and ranges from
35 to 142 GRT. The purse seine vessels had longer berthing days and the daily fuel consumption
is higher. The less efficient purse seine tuna fishing vessels are usually cast-off vessels that were
bought or chartered from countries such as the United States, Taiwan and Japan (Aprieto, 1995).
Fishing Periods
In general, fishing operations are restricted during monsoon seasons. The season usually
starts from May to October (Southwest monsoon (SWM) or Habagat) and also from November
4 The usage of FADs has generated a number of studies that recommend either limiting, regulating or banning FADs
because of its effects on tuna sustainability. For example, Cabral, Aliño, and Lim (2014) propose to transform FADs
into fish enhancing devices (FEDs) because putting FADs into an already overfished area accelerates the decline of
tuna stocks. However, Davies, Mees, and Milner-Gulland (2014) recommends that FADs be actively managed
because small scale fishermen derive their livelihoods from operating these devices. Finally, Baske et al. (2012)
notes that assesment methods for FADs need to be improved in order to accurately measure the number of stocks so
that superior strategies in managing FADs can be introduced.
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to February (Northeast monsoon (NEM) or Amihan). The fishing months in Mindanao usually
coincides with monsoon months because it starts from February to June and from August to
October. Likewise, Aprieto (1995) revealed strong correlations between recorded peaks in catch
rates and SWM and the inter-monsoon periods. However, our technical inefficiency model
suggests that vessels operating in the first quarter of 2012 have an inverse relationship with
technical efficiency. The technical efficiency score for the first quarter is 0.79 and is the lowest
among the quarter periods (Table 6). From the total output sample, 27% (21 t) of the catch was
unloaded in the first quarter while the bulk were distributed among the remaining quarters. The
average fuel consumption and number of effort days did not vary across quarters. Similar trend
can be observed in the output levels of South Cotabato province. The total volume of tuna
landings in the province have been declining during the 1st quarter. There was a 9% decline from
the 4th quarter of 2011 to the 1st quarter of 2012 and another 11% decrease from the 1st quarters
of both years. This may provide evidence that during this period, tuna catch levels were low.
Fishing Grounds
The major tuna fishing grounds in Mindanao are found in Moro Gulf and those extending
in the North of Celebes sea (Aprieto, 1995). Because local stocks continue to decline
significantly, Philippine tuna fishing vessels started expanding fishing operations into Indonesia
particularly in the North Sulawesi waters (Yamashita, 2008). In this paper, we considered five
fishing grounds namely Moro Gulf, Sulawesi (Celebes Sea), Sarangani, Pacific Ocean and
Kalamansig. The bulk (95%) of the sampled vessels’ total annual catch were harvested in the
Moro Gulf while 1.7% were caught in Kalamansig, an adjacent fishing ground from Moro Gulf.
However, no statistically significant relationship existed between fishing grounds and the sample
fishing vessels’ technical efficiency.
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CONCLUSIONS AND RECOMMENDATIONS
The annual tuna catches from the Philippines have been declining while tuna imports
continue to increase. With this trend, there is a need to improve the efficiency of tuna vessels in
the Philippines. In this study, we utilized the technical efficiency approach by applying the
Stochastic Frontier Analysis. From the hypotheses tests and parameter values, we used a Cobb-
Douglas production function in specifying the technical inefficiency model. With an average
technical efficiency score of 0.79, our findings suggests that the efficiency levels of fishing
vessels operating in General Santos City can still be improved by approximately 21%. The likely
source of improvement may emanate from increasing the berthing days because this will shorten
effort days at sea. This implies that improvements in efficiency maybe gained if the effort days
of the vessels were restricted. In terms of vessel type, the focus of the improvement should target
the operations of purse seiners and ring netters which unload in harbor and market 3. Also, we
found that handline fishing vessels were more technically efficient than the other two types of
fishing vessels. Moreover, vessels operating in the first quarter of 2012 exhibited a negative
relationship with technical efficiency.
Also, we recommend that all other primary inputs that affect the technical efficiency of
tuna fishing vessels be validated through the use of primary data in surveying specific vessel
types (i.e. handline, ringnet or purse seine). This approach may provide more specific solutions
for each line of tuna fishery. Furthermore, we recommend that an ecological efficiency analysis
that considers the undesirable output of juvenile and undersize tuna catch as the dependent
variable be conducted in order to address the technical and ecological efficiency considerations
of the vessels. This may provide more policy options which the tuna industry can use in order to
sustain its catching operations.
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ACKNOWLEDGEMENT
This research was funded under the Higher Education Regional Research Center
(HERRC) - XI hosted by the University of the Philippines Mindanao and supported by the
Philippine Commission on Higher Education (CHED).
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