lthough the destruction of coral reefs and mangroves are significant causes
of declines in fish catch, probably the biggest cause is simply too much
fishing effort or overfishing. It has been shown that progressive changes
in the reef fish community composition will result from sustained fishing
with a variety of relatively unselective fishing gear. This effect is
made worse by using selective fishing gear such as spear or by focusing
on species easily caught. The end result of these pressures will be an
exploited community composed largely of the least catchable or desired
species of fishes and in which the most prized are extinct or nearly so.
Fisheries scientists have defined overfishing from both biological and
economic viewpoints. Biological overfishing may be one of three forms
(Pauly 1990). The first form, growth overfishing,
occurs when fish are caught before they have a chance to grow or when
immature fish below the required age for reproduction and harvest are
gathered. When the adult fish population is caught in large numbers so
that fish reproduction is gravely impaired and recruitment of young fish
to replenish stocks is compromised, a second form of overfishing called
recruitment overfishing results. If the decline in a once
abundant fish stock due to fishing is not compensated for by an increase
in the stocks of other species, on the other hand, the consequence is
referred to as ecosystem overfishing.
many fishers with more efficient gear
are chasing after fewer and fewer fish.
Overfishing is also sometimes described as Malthusian overfishing,
which fisheries expert Daniel Pauly of the University of British Columbia
Fisheries Centre defines as a condition that arises when poor fishermen,
faced with declining catches and lacking any other alternative, initiate
wholesale resource destruction in their effort to maintain their incomes.
Malthusian overfishing, according to Pauly, may involve in order
of seriousness, and generally in temporal sequence: 1) use of gear and
mesh sizes not sanctioned by the government; 2) use of gear not sanctioned
within the fisherfolk communities and/or catching of fish reserved
for a certain segment of the community; 3) use of gear that destroy the
resource base; and 4) use of gear such as dynamite or sodium
cyanide that do all of the above and even endanger the fisherfolks themselves.
When incomes of fisherfolk continually decline, the condition is described
as economic overfishing. This condition has far-reaching implications
on the value of fishery resources to society in general and to particular
fishing communities and fishers (Copes 1972; Anderson
1986). It includes the following features:
- Overcapitalization and oversupply of labor. There are too many boats
and too many fishers chasing a declining fish stock. Money used to buy
boats and other equipment should have been used for other investment
opportunities outside of the fishery sector. Labor should also be applied
outside of fishing, assuming there are alternatives.
- Dissipation of economic rent from excess fishing effort and not levying
license fees and market controls. Society loses because of an absence
of user fees, licenses, and other limits to entry required to increase
the cost of fishing. The low cost of entry attracts too many participants
in an open-access regime.
- Loss of consumers and producers surplus (their benefits)
as prices go up for consumers and profits decline for producers. Consumers
are plagued with high prices and producers experience declining profits
and eventually losses.
- Depreciation of asset value of the resource. In the Philippines, we
are losing more than US$400 million a year to overfishing of demersal
and small pelagic species (Dalzell et al. 1987).
Meanwhile, total net present value of quantifiable loss from overfishing
1 km2 of coral reef over a 25-year period and discounted at 10 percent
is US$108,900. Overexploitation in the Lingayen Gulf fisheries has resulted
in depreciation of PhP390 million/year from the time maximum economic
yield was reached during the mid-1980s (Trinidad
et al. 1993; Padilla et al. 1997; White
and Cruz-Trinidad 1998).
Signs of an overfished area
Without some knowledge of the history of the area and its catch characteristics,
it is sometimes difficult to determine how severely an area is overfished.
But there are a few basic questions that, when answered, will indicate
that an area is overfished even if the extent of overfishing requires
more research to evaluate accurately. Following are some manifestations
- Changes in species composition
- Increasing incidence of trash fish (less valuable fish)
- Increasing incidence of squid
- Decreasing incidence of targeted species such as: groupers, snappers
(Lutjanidae), breams, flatfish (Psettodidae), and others
- Decreasing incidence of specialty species such as stingrays (Dasyatidae),
manta rays, sharks, and others
- Change in average size of fish
- Typically large-backed fish such as jacks or groupers are less than
- Fish are found to be smaller than its known size at maturity
- Change in total fish catch
- Decrease in catch determined by comparing catches over a time series
that includes at least a 10 year time span using informal or formal
data sets of catch records
- Change in catch-per-unit effort (CPUE)
- Determine an appropriate measure of fishing effort, i.e., number of
fishers, number and/or tonnage or horsepower of boat, time spent, etc.
- Compute for CPUE by dividing total fish catch by the selected measure
of effort; compare past and present data with same fishing area or other
- Decline in average income of fishers
- Compare average income over time after accounting for price changes
- More boats not going out to fish or not used as frequently
- More fishers in area due to lack of employment or migration to area
- Absence of seabirds hunting for schools of fish
All of the above indicators used to determine the presence and extent
of overfishing depend on some type of historical records or memories.
There must be a base point in the past from which recent or present data
can be compared. Time series analysis cannot be pursued without some data
from the past in credible form. Oftentimes the only reliable source of
such data is through interviews with people who have lived and worked
in the area for 15 or more years and are able to recollect the way it
was before. Fishers who have used the same methods for many years in the
same area are excellent sources because they measure their catch every
time they fish.
Causes of overfishing
In the Philippines, the direct cause of overfishing - excessive fishing
effort - is easy enough to explain, but the underlying causes of overfishing
and the conditions that encourage it are far more complex. Clearly, excessive
effort occurs in an open-access fishing regime, but what controls the
number of fishers in the first place?
Human population growth that doubles in about 35 years is a major factor,
but the endless influx of people to coastal areas reflects not only the
countrys weak population program - it also reflects the failure
of other economic sectors to provide sustained employment. The economic
context and availability of alternative employment determine who decides
to fish. A weak economy and the lack of economic opportunities result
in unemployment and increased poverty. Poverty increases the number of
fishers - landless and having nowhere to go, the unemployed are pushed
to the coastal zone and many turn to fishing for a living. As their numbers
increase, poor fishers become a major factor in the mass destruction of
fish habitats through the use of destructive fishing methods and the application
of too much fishing effort. Lack of law enforcement then enters the equation
because most destructive fishing practices have long been illegal! And,
without instruments to limit access, the influx of fishers continues.
Excessive fishing effort is linked to other issues as well. Government
policy has certainly contributed to overfishing in the Philippines. During
the 1960s and 1970s, the government encouraged capital investment in fisheries
and full exploitation of fish stocks, luring fishers with the prospect
of earning profits from very little investment. In fact, however, the
fishing industry has been operating largely on government studies. Cost
and returns studies indicate that more than 90 percent of the production
cost in the fishing business is actually operating cost, and that fixed
costs such as licenses, taxes and fees are very minimal (DAP
The Lingayen Gulf experience provides a classic example of how the explosion
of fisher population - and the corresponding increase in the number, power,
and efficiency of fishing gear - can deplete fishery stocks to alarming
levels. Fig. 1 shows how demersal biomass in the Gulf decreased steadily
as fisher population increased between 1950 and 1980, and then plummeted
when the population exploded in the 1980s (Silvestre
1990). The trend may well be projected to a national scale: nationwide,
during a 40-year period beginning in 1948, the total number of vessels
in the municipal sector has grown from an estimated 20,000 (83 percent
of which were non-motorized) to 500,000 units (with a higher portion of
motorized boats) (Dalzell and Corpuz 1990).
1. Relative indices of demersal biomass, number of fishers, and number
of commercial trawlers in Lingayen Gulf, from the 1930s to the 1980s (Silvestre
Tragedy of the commons
Open access explains why fishing effort has consistently increased in
the Philippines. ArticleXII, Section II of the Philippine Constitution
states that fisheries are owned by the general public and guarantees use
of the resource for all citizens. Indeed, Philippine fisheries have all
the features of the open-access model described by RJ Oakerson in a 1985
paper (Oakerson 1985):
- No exclusivity of use. Not only are coastal dwellers entitled to use
the resource but also fishers from contiguous municipalities, those
from distant municipalities, and those from the agricultural communities
and uplands as well.
- No limits to use. Each fisher decides on where to fish, how many hours
to fish, and what gear to use.
- Indeterminate physical boundaries. The difficulty of excluding potential
users is exacerbated by the inability to apportion areas to selected
users. If this problem is surmounted by legal means, the difficulty
of enforcing the rule becomes the corollary concern.
- In an open access regime, an individual fisher is viewed as a rational
economic being who engages in an optimizing behavior, that is, to catch
the greatest number of fish possible. Knowing that the resource is accessible
to everybody, the individuals rational reaction would be to harvest
as much as one can for today, because tomorrow it might be on another
fishers plate! The aggregate effect of all fishers thinking in
the same manner is disastrous to the resource. This is what we call
the tragedy of the commons (Hardin 1968).
The tragedy affects us all. Fishers lose out because fish catch is dwindling,
less valued species are being caught, cost of fishing is higher, and earnings
are depressed. Consumers lose out because fish prices. ø
Anabelle Cruz-Trinidad - Policy Advisor,
Coastal Resource Management Project
Alan T. White - Deputy Chief of Party, Coastal Resource
Mary Gleason - Consultant, Tetra Tech EM Inc.
Leo Pura -- Policy Research Assistant, Coastal Resource
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