Image #1 of sequence. Advanced Very High Resolution Radiometer SST and SeaWiFS chlorophyll comparisons for January 1998 and July 1998.

Image #2 of sequence. SST anomalies in January were close to the highest observ ed during the most recent El Nino. There is little or no evidence of the equato rial cold tongue or of enhanced chlorophyll along the equator.

Image #3 of sequence. In sharp contrast, by July 1998, a dramatic recovery had taken place. There is a well-developed cold tongue and a dramatic bloom of phytoplankton along the equator. High chlorophyll concentrations had not previously been observed over such a large area.

On average, FAO statistical area 87 provides around 45 per cent of the World's catch of small pelagic species.

Fishing gear in the Southeast Pacific Ocean from left to right: a Chilean purse seiner; a tuna purse seiner in tropical waters of the northern part of Area 87; a Peruvian purse seiner; a trawler; and a small purse seiner.

Normally an oceanographic phenomenon known as upwelling keeps the surface waters of the southeast Pacific Ocean cold and teeming with small pelagics that are fished by purse seiners. Upwelling occurs in this zone when southeasterly trade winds , produced by the South Pacific anti-cyclone, along with other facto rs drive coastal waters out to sea, forcing deep nutrient-rich waters to rise.

The result of changes of water temperature on fisheries is significant. As water temperatures rise and nutrient levels decline, shoals of cold-water-loving small pelagics scatter and descend to depths of 150 to 200 meters, where they are not accessible to traditional surface purse seiners, or they migrate south.

For reasons not completely understood, in some years the anti-cyclone is less powerful than normal. The weaker winds it produces fail to draw cold waters up to the ocean's surface, thus opening the way for warm, nutrient-poor tropical waters. These changes in water temperature and climatic conditions are known as "El Nino".

The Mediterranean is a semi-enclosed sea relatively low in nutrients and fishery productivity. It has become increasingly polluted owing to runoff by nutrients from waste disposal and agriculture. Catch of key species such as Black Sea anchovy has fallen, relecting environmental degradation. High exploitation levels have also depleted important stocks such as blue fin tuna and swordfish.

The Mediterranean and Black Seas fall within the same FAO statistical area (Area 37) but, apart from some migratory species, their fisheries and resources are mostly separate. The total catch from Area 37 showed a generally positive trend until the mid-1980's, reaching about 2 million tons.

Currents and Temperature - Atlantic waters enter the Mediterranean through the Straits of Gibraltar and flow east along the North African coast, becoming more saline as evaporation exceeds freshwater inflows. Thus, the Mediterranean is mor e saline than the Atlantic. Strong temperature, salinity, and available nutrien t gradients lead to high biodiversity reflected by regional faunal differences.

A wide variety of fish and shellfish species support a mostly small-scale fisher y, operating near to the coast. Over 40 types of gear are used in the Mediterran ean. Most common type is trawlgear for benthic species; coastal purse seiners for small pelagics; trammel and gillnets for inshore species; and purse seines, long surface gill nets, and longlines are used for large pelagic fish.

High seas fisheries: Ocean pelagic resources living near the surface are exploit ed by purse seiners and surface long-liners . Top: Italian purse seiner fishing in the central Adriatic. Middle: Bluefin tuna caught in the South Tyrrh enian by a purse seiner. Bottom:Distant-water surface longliner operating in the Mediterranean.

Coastal Pelagic Fisheries: Small coastal pelagic species are exploited by coast al purse seiners. Top: Coastal purse seiners in the harbor of Fuengirola, Spain . Bottom: Anchovies caught in the Alboran Sea by coastal purse seiners and landed in Fuengirola, Spain.

Demersal Fisheries: Species living near the bottom are exploited by trawlers. Top: Landings from trawlers in the market of Mazara del Vallo (Sicily), Italy. Bottom: Spanish trawler in the northwestern Mediterranean.

Littoral Fisheries: Coastal species are exploited by small-scale gear (gill nets , trammel nets, bottom longlines and traps). Top: Small scale gear boat. Acitr ezza (Sicily), Italy. Lower left: Landings of small-scale vessel. Gallipoli ( Gulf of Taranto), Italy. Lower right: Trammelnetters. Porto Cesareo (Gulf of Taranto), Italy.

"Caballitos de totora", small one-man fishing boats.

Peruvian purse seiners.

Young fisherman preparing nets

Fisherman in Liberia

Ghana Boat in Liberia

Boy mending net

Boy and women preparing fish

Sao Tomean artisanal fishing boat

Sao Tomean artisanal fishing boat

Sao Tomean artisanal fishing boat

Sao Tomean artisanal fishing boat

Sao Tomean artisanal fishing boat

Sao Tomean artisanal fishing boat

Sao Tomean artisanal fishing boat

Sao Tomean artisanal fishing boat

Sao Tomean artisanal fishermen obtaining gasoline for boats.

Sao Tomean artisanal fishing boats

Sao Tomean artisanal fishing boats

Sao Tomean artisanal fishing boats

Fish for sale at Sao Tomean street market

Fish for sale at Sao Tomean street market

Fish for sale at Sao Tomean street market

Artisinal fisherman selling a barracuda on the roadside

Shark being carried to the market

Shark being carried to the market

Shark being prepared for Sao Tomean market

Sao Tomean's posing with shark

Fish drying on rack in artisinal fishing village

Fish drying on rack in artisinal fishing village

Fish drying on rack in artisinal fishing village

Fish drying on rack in artisinal fishing village

Fish drying on rack in artisinal fishing village

Fish drying on rack in artisinal fishing village

Dried fish in Sao Tomean market