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Jurgenne H. Primavera

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Jurgenne H. Primavera, senior scientist of the Aquaculture Department of the Southeast Asian FisheriesDevelopment Center based in Iloilo, central Philippines, for more than two decades has been a tirelesschampion of replacing unsustainable aquaculture practices with sustainable ones. In her early researchcareer, in the 1970s, her studies of the early phases of the shrimp life cycle contributed to aquacultureknow-how and practice, enabling this food-producing strategy to flourish in the world’s mangrove areas,

including some in her own country. As she learned first-hand about the environmental and socioeconomic perils that poorly managedand overextended aquaculture can bring, she began to investigate and develop mangrove-friendly aquafarming methods in order tomove toward a sustainable industry that provides food and jobs while also preserving the environment.Trained in zoology and marinescience,Primavera has published and lectured extensively on aquaculture and mangrove issues. Among her numerous awards and hon-ors are her induction as a foreign member into the Swedish Royal Academy of Agriculture and Forestry and an honorary doctoral degreefrom Stockholm University. Earlier this year, she was chosen as a Pew Fellow in that organization’s program in marine conservation.

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57

As I write on this late June afternoon, myheart grieves amid news that a youngcouple, dearly loved former research

colleagues living in the north of Panay Islandin the Philippines where I work, had been shotover a fishpond dispute. The owner, it seems,did not want them to use a shortcut on his prop-erty that led to the pond the couplewas renting from him. Bullets shat-tered the jaw, collarbone, and colonof the husband, a marine biologistwho miraculously survived, butthey proved fatal to his wife, anaquaculture nutritionist and univer-sity instructor.

The incident takes me backdecades to my home island of Min-danao when rifle bullets strafed ourcampus cottage during a short-lived rebellion. My family anda neighbor crouched inside thebathroom, while the battle betweenrebels and government soldiersraged for 4 long hours. The growing insur-gency forced me to give up my teaching job atMindanao State University and flee to the quietof the Visayas, in the central Philippines,where I accepted a research position with theAquaculture Department of the South-east Asian Fisheries Development Center(SEAFDEC/AQD).

Fast forward to the present, to anotherpotential conflict elsewhere in northern Panay.This one is centered on the small-scale cutting

of trees in and near a magnificent mangrovestand of Avicennia rumphiana trees, some ofthem up to 8 m in circumference. This locationhas been among our study sites since 1997.But to make an official complaint would placemy colleagues and me in harm’s way fromthose who earn income by planting the cleared

area with Nypa palm or convertingit to ponds.

Troubles like these come withthe mission of protecting theworld’s mangroves—the lushlyforested environmental bufferzones by which the sea meets landin so many places around theworld—even as these areas be-come ever more exploited foraquaculture and other uses. It is amission that teeters on the always-difficult negotiation by whichecological and environmentalgoals, on the one hand, and eco-nomic, social, and immediate

human needs, on the other, are adjudicated.I have observed this difficult dynamic

firsthand since the mid-1970s when thefield of aquaculture, the farming of aquaticand marine plants and animals, was gettingstarted. Indeed, my first studies in this area—on the growth and survival of shrimp inearthen ponds and production of breeders forhatcheries—contributed to the foundation onwhich increasingly efficient shrimp farmingdeveloped, so often, as it has turned out, to

the detriment ofmangrove habitats.

Mangroves at RiskAquaculture ranks as a phenomenal successstory in global food production. In 1975,when I joined the SEAFDEC/AQD, aqua-culture contributed 8% to the overall yieldof the world’s fish harvest; now it providesmore than one-third of the yield of theworld’s fisheries. Total aquaculture produc-tion in 2003 was 54.8 million metric tons,valued at $67.3 billion in U.S. dollars. Morethan 90% of this output comes from Asia,where aquaculture has its origins.

As with land-based agriculture, all of thisaquatic food production and economic activ-ity has come with environmental problemsand social conflicts. Foremost among theseis the loss or modification of habitat inplaces where aquafarmers clear mangrovesfor ponds and where they install cages or pensabove seagrass beds and coral reefs. Otherenvironmental effects include the loss ofbycatch (unwanted fish and invertebratespecies) during the collection of wild “seed”used for stocking in ponds and of adult brood-stock for hatcheries, introduction of exoticspecies, spread of parasites and diseases, inter-actions of escapees from ponds or pens withwild populations, misuse of chemicals andantibiotics, salinization of soil and water, andcoastal pollution. Many of these ecologicalimpacts of shrimp aquaculture have brought

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GLOBAL VOICES OF SCIENCE

Mangroves, Fishponds, and the

Quest for SustainabilityJurgenne H. Primavera

ESSAY

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along social problems, among them privati-zation of public lands and waterways, thedecline of open-sea fisheries, rural unem-ployment, and social disruption.

Even the seemingly reasonable assump-tion that aquaculture is an efficient way toproduce new protein is undermined by thedependence of shrimp, salmon, and other cul-tured aquatic carnivores on raw fish and onfish meal and oil in pelleted feeds. Carefulcalculations indicate that some culturedspecies actually are net consumers of fish.

In the 1980s, I began to ring warning bellsabout the perils of runaway shrimp farming.

At the time, aquaculture was perceived as thecoming Blue Revolution that would help solveworld hunger, provide jobs, and fight poverty.Because of my cautionary views, I becamemarginalized in aquaculture circles. At somemeetings I was ostracized and my researchpapers sometimes seemed harder to getthrough editorial decision-makers than thereviewers’ comments would have suggested.Even so, other researchers would subse-quently confirm my conclusions on, for exam-ple, the boom-and-bust nature of unplannedand poorly managed shrimp culture. And inrecent years, momentum to develop sustain-able aquaculture practices has been building.

For my part, I have received invitationsfrom foreign groups, including the GlobalWetlands Economics Network and theInternational Foundation for Science, toexpose the plight of mangroves and share myideas about aquaculture sustainability. Attimes, I have done so in high-profile mediaoutlets, such as a BBC documentary in 2002.Although I had always been confident thateven my early alarmist attitude was justified, Ireceived my final peer vindication last yearwhen Stockholm University presented mewith a Ph.D. in science honoris causa forshowing “… that mangroves are key areas for

recruitment of fish and shrimp and that devel-opment of conventional shrimp farming mayhave far-reaching negative economic andsocial implications… .”

For greater sustainability, the aquacultureindustry must acknowledge its interdepend-ence with fisheries and other stakeholders.Ecologically damaging practices need to bereplaced with ecologically sound ones, such aslocating culture ponds outside mangroveswhere possible, using native species whoseinevitable escapes into nearby waters would berelatively innocuous, and stocking hatchery fryrather than wild seed whose collection entails

the loss of bycatch.Because surrounding water-

ways can be the source as wellas recipient of contaminants andpathogens, systems of low waterexchange between ponds and thesurrounding environment canminimize such risks. Levels ofsuspended solids or sediment arereduced if pipes that provide aera-tion are set on the pond bottom,rather than on the surface, and alsoby means of settling ponds. Waterquality can be maintained withnatural biofilters such as clams andother bivalves. Probiotics are com-mercial suspensions of appropriatetypes of bacteria added to the pondthat operate on the principle ofcompetitive exclusion (of harmful

bacteria). The so-called greenwater techniqueenhances shrimp growth and survival bymeans of a combination of phytoplankton andthe presence of herbivorous fish in the pond.Finally, lower stocking densities of shrimpand their polyculture with suitable fishspecies can minimize waste levels and pro-duce synergistic benefits.

Already, the culture of seaweeds and fish incages in subtidal bays and rivers is compatiblewith adjoining mangroves and suitable forfamily-level operations.

But there remains aneed for mangrove-frien-dly aquaculture technol-ogy in intertidal forests,in which mangrove treesspend high tides withtheir roots submergedand low tides with theirroots exposed. That’s whyone of my current proj-ects, funded by the Euro-pean Commission, is todevelop sustainable so-called aquasilviculture. Anapproach I have developed,which combines the rear-ing of mud crabs inside

intertidal pen enclosures, has been replicated bylocal people’s organizations in the Philippines.Meanwhile, several studies have shown thatmangrove estuaries can process nutrients, suchas those from fertilizers, in aquaculture pondeffluents at least over short spatial and temporalscales. That opens up the possibilities of inte-grating intensive aquaculture with natural orconstructed mangrove wetlands in a way thatcould be sustainable through careful manage-ment and planning.

A Menagerie of Mangroves My earliest training was in zoology, and whenI began studying the taxonomy of mangroves,I found the diversity of these habitats chal-lenging. On a trip to the Mai Po, Hong Kong,mangroves in 1993, experts from Thailandand Vietnam effortlessly called off the scien-tific names of mangrove species—Avicenniamarina, Kandelia candel, Aegiceras cornicu-latum, etc. Feeling ignorant, I vowed to masterthe Indo-Pacific species of mangroves. Indeedit took me 10 years to write and publish, withUNESCO support, the Handbook of Man-groves in the Philippines—Panay, whichcame out last year. The diversity of mangrovesand their wide distribution in the archipelagoin the past are reflected in the names of manycoastal towns and villages. The name of thecountry’s premier city, Manila, derives fromMaynilad, meaning there is nilad, referring tothe mangrove Scyphiphora hydrophyllacea,which grew profusely along Manila Bay inpre-Hispanic times.

Mangroves, seagrass beds, and coral reefsbordering the 7150 Philippine islands havecontributed appreciably to the livelihood andwell-being of coastal communities over thecenturies through their provision of variousgoods and services. Foremost among man-grove products are fish, shellfish, and otherinvertebrates that provide the most availableand inexpensive protein in the Filipino diet.Other natural benefits afforded by mangrovesinclude coastal protection, erosion control,

sediment trapping, andrecycling of nutrientsfrom terrestrial run-offand river discharges.

Latest estimates, asof 2000, have placedthe global coverage ofmangroves at 15 millionhectares (ha), a drasticdecline from 18 millionha in the 1990s. Thelosses have been partic-ularly heavy in South-east Asia, which hosts athird of total mangrovearea. The anthropogeniccauses of such losses

Water world. Boys swim in this creek bya healthy intertidal mangrove duringhigh tide.

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Vanishing mangroves. The expanse of fish and shrimp pens inthe foreground of this aerial view of Dagupan in the Philippineprovince of Pangasinan used to be filled with mangroves.

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include overexploitation of mangrovesand conversion of mangroves to settle-ments, rice fields, salt beds, touristresorts, and industrial facilities. Butbrackishwater pond culture, whichdates back to 1400 in Java, has alsotaken its toll. Many thousands ofhectares of culture ponds in the Philip-pines and Indonesia were carved outof mangrove swamps because thesehabitats were considered ideal forgrowing milkfish (Chanos chanos), afood fish favored by local people.Around half of the 279,000 ha ofPhilippine mangroves that disappearedbetween 1951 and 1988 were convertedinto ponds mainly for milkfish, butalso for shrimp.

Aggressive mangrove and wet-lands development became nationalpolicy in the Philippines in the 1950s.Some of these policies supportedaquaculture development by enforc-ing a form of rent control on the man-groves. The original fee for leasing apond was PhP50, or about $2/ha peryear. This fee was way out of line with theestimated values of $538/ha per year and $42to $156/ha per year, respectively, for fish andwood harvests from Philippine mangroves.By underpricing the rights to harvest publicforests and by not penalizing low pond pro-ductivity, these policies and practices encour-aged rampant conversion of mangroves toaquaculture ponds.

Both a 1991 decree and one in 1992 man-dated an increase in the rental to PhP1000, orabout $20/ha per year, but its implementationwas delayed indefinitely on both occasions bya strong fishpond industry lobby. In the past 2years, the government presented a series ofexpert witnesses, including myself, who citedpublished valuations from the mangrove litera-ture and aquaculture studies of mangroves andfishponds to justify the pond rental increase.The court is expected to rule within the year.

Actually, numerous laws, decrees, andordiances aim to protect remaining mangroveareas. These include guidelines for mangrove-pond conversion and reversion of abandonedponds to forest. Ownership policies, such asthe Mangrove Stewardship Agreement thatlegitimizes de facto claims of local communi-ties over coastal resources, improve the successrate of replanting programs. Even so, coordi-nation is lacking between the national forestryand fisheries agencies tasked to administermangroves and ponds. Legislation to con-serve, protect, and rehabilitate Philippine man-groves has not been wanting—it is their imple-mentation that is generally weak, hampered byinadequate manpower and resources, and over-all lack of political will to enforce the laws.

Consider the re-quirement by a num-ber of “greenbelt” pro-mulgations that a man-grove strip of 20 to50 m along riverbanksand one of 50 to 100 mfacing the open seasbe maintained regard-less of the economicactivity in the area.Today, an aerial viewof the Philippine coast-line will show a mono-tonous succession ofponds with hardly anygreen signs of suchmangroves.

As the December2004 tsunami hasshown, this is notmerely a matter ofaesthetics. Man-madestructures such asshrimp/fish farms andtourist resorts along

the coastline are no match for rampagingwaters. It is time to enforce these greenbelt andother mangrove-preserving laws, because onlya solid wall of trees can slow down a movingwall of water. More than ever, there is a need topreserve or rehabilitate mangrove-beach for-ests and coral reefs to serve as natural barriersthat diminish the tremendous wave energy gen-erated by tsunamis, as well as by typhoons.Tsunamis appear every 20 to 50 years in thePhilippines, but in a single year 20 typhoonsmay devastate the country by inflicting massivelosses of life and property.

Mangrove SenseOnly a fifth of the 500,000 ha of Philippinemangroves at the turn of the 20th centuryremain, whereas brackishwater ponds haveincreased almost fourfold, from 61,000 hain 1940 to 230,000 ha at present. Many ofthese ponds have no associated legalpapers—either the lease has expired or theapplication is pending. Often single fami-lies own up to hundreds of hectares of pondarea. Twenty hectares is the most that aFilipino pond operator can realisticallymanage by himself, so many ponds areunderutilized or abandoned, and productiv-ity is low compared to that of Thai shrimpfarms, which average 2 ha or less. By reduc-ing farm sizes, Filipino aquaculturists canincrease pond yields and afford to pay thestill modest lease fee of PhP1000/ha peryear. The remaining areas, especially thosefacing waterways, could be reverted togreenbelts, finally coming into compliancewith Philippine laws. Also, by redressing

the present imbalance between the respec-tive areas of mangroves and ponds, aqua-culturists can embrace the more holisticapproach, known as Integrated CoastalZone Management, which incorporates anunderstanding of the complementary ratherthan competing roles of aquaculture andmore traditional open-sea fisheries.

My environmental bias goes back to achildhood imprinted with mangoes, avocados,and a dozen other tropical species of backyardfruit trees, as well as yearly floods due to ram-pant logging that had denuded the forests inmy home province. The floods were particu-larly bad and had downed many bridges in1961 when, as a high school student, I took thegovernment science examinations. To travel tothe testing center in the next province, myfather and I had to cross rivers on coconuttrunks or bamboo poles. A decade later, mypassion to work for a sustainable environmentwas greatly reinforced by my participation inthe historic 1972 U.N. Conference on theHuman Environment in Stockholm.

I am determined to continue mentoringyounger researchers in sustainable aquacul-ture and mangroves. Sadly, most Filipino stu-dents of marine biology prefer the “glam-orous” coral reefs and seagrass beds tomuddy, mosquito-infested mangroves. This isunfortunate because, given a chance, man-groves can be thoroughly enchanting, the mudand insects notwithstanding. Imagine numer-ous white filaments of Sonneratia alba flow-ers gently falling from the canopy in the earlymorning breeze, or the unspeakable beauty ofthousands of fireflies lighting up Sonneratia

caseolaris trees on a moonless night. We scientists in developing countries need

to come down from the Ivory Tower and dis-seminate results not only in peer-reviewedjournals but also through advocacy and thepopular media. We must not forget our heartseven as we apply our minds. We do science notin a vacuum but against the grinding povertyand environment-unfriendly character ofmodern times, and we can use our scientificknowledge to reduce suffering and make lifemore full for fellow humans and creatures.With a Pew Fellows grant in marine conserva-tion, I will pursue initiatives in mangrovemanagement and rehabilitation through edu-cation and local governance. Success will behad on the day my grandchildren walk withme through these habitats, understanding theirimportance, appreciating their diversity, andcaptivated by their magic.

The author is with the Aquaculture Department,Southeast Asian Fisheries Development Center,Tigbauan, Iloilo 5021, Philippines. E-mail: jhprima@aqd.saefdec.org.ph

10.1126/science.1115179

Postharvest portrait. Milkfish,and perhaps some shrimp andcrabs, have just been harvestedfrom this drained milkfish pondin Iloilo Province, central Philip-pines. With mangrove stumpsnow visible, it will be dried,filled, and restocked with “seed”organisms for the next crop.

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