marine and coastal areas -...

ENVIRONMENT OUTLOOK38

Marine and coastal areasThe oceans are the largest ecosystems on the planet.They are as rich and diverse as any land ecosystem,but remain practically unexplored. Although the deepseas are still, in general terms, unpolluted, there isalready evidence of environmental degradation insome areas as well as deterioration of many marinespecies.

39GEO - LATIN AMERICA AND THE CARIBBEAN

The marine coastal environment, by contrast, hasclearly been significantly affected by habitat trans-formation and destruction, by over-fishing, and bypollution, mostly resulting from land-based activi-ties far away from the sea.

More than one-third of the world population livesless than 100 kilometres from the coast (Cohen etal. 1997). In Latin America and the Caribbean, where60 of the 77 largest cities are on the coast, that fig-ure jumps to 60 per cent.

Marine and coastal systems in the region supportthe complex interactions of diverse ecosystems, withgreat biodiversity, and are among the most produc-tive in the world: they are the breeding grounds forcommercial species, they generate revenue fromtourism, and they act as protectors. Several of thelargest and most productive estuaries in the worldare located in this region, namely the Amazon andPlate rivers on the Atlantic coast and the Guayaquiland Fonseca on the Pacific coast. The coast of Be-lize has the second-largest coral reef in the world.The waters off the coasts of Chile and Peru containone of the five largest fisheries in the world, and thefastest-growing fisheries in the world can be foundnear the coast of Argentina and Uruguay (IDB 1995).

The region’s coast is 64 000 kilometres long andincludes 16 million square kilometres of maritimeterritory. This area plays a key role in the diversesub-regional and intra-regional dynamics. Thecoastal areas of the Greater Caribbean, for example,receive sediment from, in order of importance, theMississippi River (United States of America), theMagdalena River (Colombia), the Orinoco River(Venezuela) and other rivers in Mexico, CentralAmerica, the Antilles, Colombia and Venezuela(PNUMA 1999b). The Gulf of Fonseca, in CentralAmerica, is the setting for productive relations inthe fishing activities of Guatemala, El Salvador andNicaragua. Significant sedimentation has been de-tected in the Caribbean Basin and in the Orinocoand Amazon River basins. Also relevant are the cli-matic relations that exist between the coasts of theEastern and Western Pacific, such as those seen inthe El Niño condition (see section ‘Climate change’below). Lastly, it is important to stress that for coun-tries like the island states of the Caribbean, Panamaand Costa Rica, territorial waters represent more than50 per cent of their total area.

Marine fisheries

The total marine catch in the region reached a peakof 21 million tonnes in 1995 (about 20 per cent ofthe world catch). From 1985 to 1995, many SouthAmerican countries doubled or tripled their catch,while Colombia increased its catch fivefold. How-ever, the catch in later years has dropped consider-ably. For 1997, the decrease was around 14 per cent(FAO 2000).

The biggest decreases in catch occurred in Peru andChile: for 1993 this represented around 80 per centof the total catch and around 30 per cent of the totalincome, which was US$4.5 billion that year (Lemay1998). Two important reasons for this are the El Niño

The marine fishery catchgrew four-fold between1975 and 1995, but hasdecreased since then

because of over-exploitation and the El

Niño phenomenon.


The impact of Chilean fisheries on exploited species*

Species Abundance (1) Total biomass (1) Exploitation rate (2) Over-exploitationJuveniles Adults

Groundfish species (from deep waters)

Southern Hake 19 % 24 % 29 % — Severe (Merluccius australis)

Golden Conger Eel — 40 % 30 % — Severe (Genypterus blacodes) (females)

Nailon Shrimp — — — — Catch smaller(Heterocarpus reedi) than authorized

Pelagic species (feeding in surface waters)

Sardine — — — 80% Extensive (Sardinops sagax) (1994) depletion

Common Sardine — — — 58 % Significant biomass(Clupea Strangomera (1998) and recruitment

benticki) decrease since 1996

Anchoveta 30 % — — — Over-exploitation(Engraulis ringens) because of recruitment

(southern Peru andnorthern Chile, possibly

also central andsouthern Chile)

Yellow Tail Jack — — — 22 to 32 % Severe crisis: total(Trachurus simmetricus (1993-1996) allowable catch has

murphy) not been reached

* Expressed in terms of the original stock percentage reduction (groundfishes) or in exploitation rates (pelagic species)(1) Relative to the level existing before the commercial exploitation of the species.(2) As a proportion of the estimated stocks to the last reference year (see graphs below).

Source: Compiled from Moreno, 1999.

phenomenon and the over-exploitation of the fish-eries resource.

Between 1970 and 1983, the catch in Peru plum-meted from 12 million to 2 million tonnes due to theEl Niño events. Although in the following decadethe catch volume increased significantly, reaching8.9 million tonnes in 1995, it then dropped again to7.8 million tonnes in 1997 (IDB 1995; FAO 2000).It is likely that this latest decrease was caused by the1997–1998 El Niño.

The other key factor is over-exploitation of fisheryresources: 80 per cent of the commercially exploit-able stocks in the south-western Atlantic and 40 percent of those in the south-eastern Pacific are nowfully exploited, over-exploited or depleted (FAO1997c).

The Chilean case is a good example of this. Thecountry witnessed a steady increase in its catch overthe past few decades. In the period from 1990 to1998, the GDP of the Chilean fishing industry grewat an average annual rate of 10.7 per cent, while ex-ports grew 5.5 per cent from 1990 to 1996 (Chile,Central Bank 1998). However, the average catch in1998 decreased more than 43 per cent compared with1997, reaching its lowest point in the decade at 3.6million tonnes. Fish product exports dropped 31 percent compared with 1997, and the returns decreased10.6 per cent (Chile, Ministerio de Economía,Subsecretaría de Pesca 1998).

The dramatic fall in the Chilean catch is directly re-lated to a decrease in landings of yellow tail jack(Trachurus simmetricus murphy) and anchovy(Engraulis ringens), the major components of the


Over-fishing and the1997-1998 El Niño

phenomenon have causeda dramatic decline inChilean fish catch.


country’s catch. The quantity of yellow tail jack be-gan to decline in 1997 as a result of over-fishing in1994, 1995 and 1996, when landings exceeded theaverage of previous years, while the anchovy catchwas affected in 1998 by the El Niño conditions(Chile, Ministerio de Economía, Subsecretaría dePesca 1999a).

Aquaculture

Many fishing activities – industrial, artisanal andrecreational – co-exist in the Caribbean sub-region.Total catches by the principal fisheries increasedfrom approximately 189 000 tonnes in 1975 to amaximum of 268 000 tonnes in 1985, before declin-ing to around 146 000 tonnes in 1995. In 1996 and1997 the volume remained at a similar level, withminor oscillations. According to an FAO assessment,around 35 per cent of the Caribbean stocks are over-exploited (FAO 1997c). This sub-region also has thehighest percentage of waste, mainly as a result ofshrimp trawling.

Fish farming is less important in Latin America andthe Caribbean than it is in some other tropical re-gions, although it is growing, as are its environmen-tal impacts (Lemay 1998; PNUMA 1999b). In Ec-uador, Colombia and the Dominican Republic,shrimp farming has developed significantly, and in1995 the region as a whole produced 21.6 per centof the global harvest of this species.

Aquaculture in Chile is growing at more than 30 percent per annum compared with a global increase ofonly 9.5 per cent. These activities are focused onsalmon farming, induced by favourable export mar-kets, and they generate some US$450 million peryear in export revenue. Salmon exports in 1997reached 145 000 tonnes (Chile, Ministerio deEconomía, Subsecretaría de Pesca 1998). During1998, various forms of salmon exports represented43.7 per cent of total fish exports; the returns result-ing from salmonid exports grew 6.9 per cent; andthe volume shipped grew 13.5 per cent (Chile,Ministerio de Economía, Subsecretaría de Pesca1999b).

The conversion of mangroves affects several impor-tant ecological functions. Mangroves are the habitatof diverse organisms, including birds, crabs and oys-ters; they provide spawning and nursery areas forfish, shrimp, prawns and lobsters; and they protectthe coastline against wave erosion (PNUMA 1999c).Other important impacts include the enrichment ofhabitats with nitrogen and phosphorus; interactionwith the food chain; oxygen consumption; interac-tion between native and planted species; the intro-duction of exotic species; and the release of bioticcompounds (including pesticides and antibiotics),chemicals, hormones and growth enhancers(PNUMA 1999c).

Tourism

Tourism represents about 12 per cent of the grossdomestic product of Latin America and the Carib-bean, and is concentrated mainly along the coasts.Some 100 million tourists visit the Caribbean eachyear, contributing 43 per cent of the combined grossdomestic product of the Caribbean and one-third ofits export revenues (WTTC 1993). It is expected thatfor the year 2005, and just in the Caribbean, scuba-diving tourism alone could generate some US$1.2billion in income (OMT 1994). Aside from generat-ing employment (10 million people were employedin tourism-related jobs in 1993), investments in tour-ism have led to important changes in land use andlife-styles along the coasts, with many rural coastalareas experiencing a gradual shift from reliance onlocal agriculture and fishing to the provision of tour-ism services and related activities (WTTC 1993).


A Coastal Risk Index for Central America

Within the framework of the CIAT–World Bank–UNEPproject for rural sustainability indices, a Coastal Risk In-dex has been prepared based on a similar index devel-oped by the Global Resource Institute, with a geo-refer-enced example for Central America.

This Coastal Risk Index is based on a port’s ‘radius of in-fluence’. Port influence is considered to be high risk for aradius of influence of 60 kilometres for medium-sized portsand 100 kilometres for large ports. The influence of theinfrastructure and population centres serves as an approxi-mate measure of coastal development, rating it in accord-ance with how close it is to the maritime area: if two hoursor less, it is considered to be highly accessible, with a riskof intermediate impact. All other coastal areas are consid-ered to be low risk.

The map shows that the influence of infrastructure isgreater in the Central American Pacific coast, while portpressure is similar on both coasts. As a result of this, 40per cent of the regional coastlines are at high risk, 10 percent are at intermediate risk, and the remaining 50 percent are at low risk.

Trade

The region’s ports are the second most importantdestination for containerized goods exported fromthe United States, and the Panama Canal is a focalpoint for maritime trade. The overall tonnage goingthrough the ports in the region increased from 3.2per cent to 3.9 per cent of the world total between1980 and 1990, and a significant increase is expectedas a result of trade liberalization and the privatiza-tion of regional ports (UNCTAD 1995). Port expan-sion and maritime trade usually go hand in hand withexpansion of trade routes along the coastline, as isalready happening in Argentina, Brazil, Ecuador andUruguay.

All these activities cause a rapid and often drastictransformation of the marine coastal zones (see mapbelow for the case of Central America).

Sediment and pollution loads

In general, the main contributor to coastal marinehabitat degradation – including mangroves, estuar-ies and coral reefs – is the conversion of land foragricultural use, housing or tourism. Also important

are the impacts caused by surface transportation ac-tivities and by hydrocarbon production and process-ing.

Erosion, caused by deforestation and poor manage-ment of agricultural land (see ‘Land and food’ sec-tion above) is one of the principal agents of coastalshallow water degradation. In the Greater Caribbean,for example, the sediment load deposited in coastalwaters is estimated to be more than ten million tonnesper year (PNUMA 1999b). At the same time, theexcessive use of fertilizers in agriculture has fur-thered algal population growth and eutrophicationin coastal lagoons. There is little information on con-tamination of coastal waters from pesticides, butmean concentrations of heptachlorine of 10.12nanograms per litre and 6.85 nanograms of dieldrin(PNUMA 1999b) have been detected in surfacewaters at the port of Bluefields, Nicaragua. In suchcountries as Brazil, Ecuador, Guyana and Hondurasthese factors are worsened by people migrating tocoastal flood plains, not only increasing the pollu-tion of the coast but also causing over-fishing andconflicts related to access to traditional fishinggrounds (IDB 1995).


Coastal water quality has been declining region-widebecause of an increase in untreated municipal wastedischarges. For example, in the Greater Caribbean itis estimated that between 80 and 90 per cent of wastewaters are discharged directly into coastal waterswithout having been adequately treated first(PNUMA 1999b).

Particularly badly affected are the region’s mangroveecosystems, which have been rapidly disappearingover the last 20 years. In Mexico, for example, up to65 per cent of the mangroves have already been lost(Suman 1994). Moreover, important environmentalfunctions are also being compromised, includingcoastline stability, fish breeding grounds, recreationaluses and flood control.

Reef ecosystems provide another clear indicator ofthe severe damage being caused to the environment.The reefs in the Caribbean and adjacent waters rep-resent about 12 per cent of the global total: today,29 per cent of the reef areas of the sub-region (seemap) are considered to be at significant risk fromrunoff and sedimentation caused by deforestation,from nutrients coming from hotel and vessel sew-age, from construction projects along the coast, and

from mining activities (Bryant et al. 1998) as wellas from increases in sea surface temperatures (seebox on page 57).

The infrastructure required for the tourism industryand for coastal settlements is a major source ofcoastal water contamination (UNEP 1999b). In ad-dition to locally produced waste, it is estimated thatmore than 700 000 tonnes of waste are generated bythe 35 million tourists who visit the Greater Carib-bean each year (PNUMA 1999b). The growing popu-larity of the Greater Caribbean as a yacht and cruiseship destination has resulted in yet more waste be-ing disposed of directly into the environment. Portfacilities in general have inadequate collection sys-tems to deal with the solid waste produced by visit-ing vessels. In extensively developed coastal areasthere is high risk of sewage pollution due to the highwater table and to the soil’s high absorption capac-ity. In places like Barbados, Jamaica and Haiti, pro-tective reef systems have been degraded byeutrophication caused by faecal material in the wa-ter, contributing to soil erosion and to beach destruc-tion. Existing measurements for Havana Bay havefound concentrations of 70 micromoles per litre ofnitrogen from ammonia and between 0.7 and 2.5

Many of the region’s coralreefs are under threat: the

Caribbean sub-region is themost affected, with 29 per

cent of its reefs at high risk.


micromoles per litre of phosphorus, causing theeutrophication of certain areas (PNUMA 1999b).

Another significant source of water pollution andcoastal sedimentation is the extraction, processing,storage and transportation of natural gas and oil, aswell as the cross-boundary transfer of hazardous andtoxic wastes, including radioactive materials andchemicals. Although there is little up-to-date infor-mation about this, several studies carried out in theGreater Caribbean show hydrocarbon concentrationsin surface waters ranging from 1.0 to 5.98micrograms per litre in Bluefields (Nicaragua) and1.0 to 1.85 micrograms per litre in Puerto Limón(Costa Rica) to 0.36 to 1.27 milligrams per litre inHavana Bay (Cuba) (PNUMA 1999b). Concerningsediments, hydrocarbon concentrations found inBluefields (Nicaragua), Cartagena (Colombia),Yucatan and Veracruz (Mexico) and Havana (Cuba)range between 6 and 1 240 micrograms per gram,with averages varying between 26.6 and 994micrograms per litre, the lowest values being foundin Bluefields and the highest in Havana, accordingto data published in 1996 and 1997 (PNUMA1999b).

Hazardous substance spills in maritime accidentsinvolving oil tankers, freighters and other vesselsare only one risk factor in this field. Most such inci-dents are caused by accidents or human errors, al-though a few have been of a criminal nature, such asdischarging ballast waters near the coast. Between1975 and 1997 thirteen oil spills were recorded, rang-ing from 50 tonnes to 6 000 tonnes, with an annualmean of 2 000 tonnes. In 1999 (to October) eightcases were reported, showing a marked reduction inmagnitude, ranging between 10 and 4 000 litres, witha total of some 16 tonnes (Bezerra 1999). However,a 1 300 tonne oil spill occurred in January 2000 inthe Guanabara Bay, next to Rio de Janeiro, affectinghundreds of square kilometres of sea waters andmangroves (including a 14 000-hectare protectedarea), and all the beaches in the bay area. The state-owned oil company was fined US$28 million (thehighest fine to date for ecological damage) in com-pliance with the new Environmental Crime Law (seeChapter Three). Estimates are that one-third of theoil spilled from 1983 to 1999 went into the oceansince the spills were caused by accidents at port ter-minals or in refineries built along the coast.

Integrated management

Successful marine coastal resource managementimplies thoroughly understanding how ecosystemswork, including habitat distribution and species com-position. Species’ interactions and their responsesto human interventions are extremely relevant tocoastal resource management. The conservation ofthese resources demands an integrated and compre-hensive framework for policy-making, planning andmanagement.

The current situation and importance of coastal ma-rine resources demand urgent action, as well as in-ternational co-operation and agreements. For theseagreements to be successful, institutional capacity-building is needed among the regional governments,in addition to efforts to promote the design, moni-toring and assessment of marine coastal activities.

Careful, co-ordinated, simultaneous planning andmanagement of all sectoral activities will bring muchgreater overall benefits than the separate implemen-tation of individual sectoral development plans. Theintegrated coastal management approach is neces-sary, bringing together into one single administra-tive framework all the human, physical and biologi-cal aspects of coastal areas.

marine and coastal areas -...

Documents