FAO Fisheries Circular No. 920 FIRM/C920
REVIEW OF THE STATE OF WORLD FISHERY RESOURCES: MARINE FISHERIES
Marine Resources Service,
Fishery Resources Division,
FAO, Rome, Italy
15. SOUTHEAST PACIFIC
FAO Statistical Area 87
This Statistical Area has a total extension of 30.02 million km2 off the western coast of South America, from northern Colombia to southern Chile, and includes a total continental shelf surface of 0.57 million km2 (Figure B15.1). The continental shelf is rather narrow with a steep slope throughout most of the Area, except for some limited zones off southern Ecuador, northern Peru and southern Chile, where the shelf might reach a maximum width of 120 km. The main oceanic islands in this Area are the Galapagos Islands off Ecuador and Juan Fernandez and Easter Islands off Chile. Areas suitable for bottom trawling can be found off northern Colombia, Ecuador, northern Peru and central and southern Chile, but the best and most productive trawling areas are in northern Peru and southern Chile.
The northern part of the Area, off Colombia and Ecuador, has a tropical climate typical of low latitudes, with mean sea surface temperatures and salinity around 28oC and 33 respectively, and relatively low productivity. Further south, off Peru and northern and central Chile, the coastal areas are dominated by the Humboldt-Peru eastern boundary current system, which generates the cold nutrient-rich coastal upwelling that makes this region so productive. Even if close to the Equator, water masses close to these coastal upwelling areas have low sea surface temperature, usually ranging from 14 to 20oC, with surface salinity in the order of 35. Further south, off southern Chile, water masses are much colder and turbulent but still highly productive, with sea surface temperatures well below 14oC and high salinity, around 44.
The distribution and abundance of fishery resources and the development of fisheries are strongly influenced by the prevailing environmental conditions. While shrimps, small coastal pelagics and large tropical migratory pelagics sustain the main fisheries off Colombia and Ecuador, small pelagics are by far the dominant species off Peru and northern and central Chile, with demersals becoming the most important fisheries further south.
The impact of changing environmental conditions is particularly noted in this area, causing large year-to-year fluctuations as well as longer-term changes in fish abundance and total production of the main exploited species. Well known are the adverse effects of the "El Niño" phenomenon on the abundance of the Peruvian anchoveta (Engraulis ringens), the once depleted and now recovering largest single-species fishery of the world. The not always negative impact of the "El Niño" phenomenon on other marine populations, including other small pelagics, hakes, shrimps, cephalopods, shellfish, sea birds and marine mammals are also worth noting.
Recent resource changes of particular relevance in this area are the severe depletion of the South American sardine (or pilchard) (Sardinops sagax sagax) and the impressive recovery of the Peruvian anchoveta, that, after the record low catch of 94 000 t in 1984, is again yielding total catches that are closer to the "pre-collapse" 8 to 10 million t per year. Worth noting are also the increases in total catches of Chilean jack mackerel (Trachurus symmetricus murphy) and squids (mostly jumbo flying squid, Dosidicus gigas) that are the other major contributors to the most recent overall increase in total production in the area.
PROFILE OF CATCHES
Fish production in the Southeast Pacific has experienced large changes and fluctuations over the past four decades. From 167 000 t in 1950, total fish production increased to 13.8 million t in 1970, declined to 3.2 million t in 1973, and increased to a new record of 19.8 million t in 1994. All this with large year-to-year fluctuations and major shifts in the species composition of mostly small pelagics, such as anchovies, sardines, herrings, and jack and chub mackerels (Figure B15.2) (Table XV). While small pelagics clearly dominate the fishery scenario in this area, noticeable changes have also occurred in other species groups, particularly hakes and other demersals, and more recently squids. To a great extent, the reported variability in the abundance and species composition in this area is caused by changing environmental conditions, often associated with changes in the "El Niño" Southern Oscillation (ENSO).
Total production in this area was and is still dominated by the Peruvian anchoveta, the major component of ISSCAAP Group 35 (herrings, sardines, anchovies, etc.) in Area 87 and world- wide. Until the early 1970s most of the year-to-year reported fluctuation in total production from this area has been due to changes in the abundance and resulting catches of this species.
After reaching the record high of 13.1 million t in 1970, the total catch of Peruvian anchoveta fell to a record low of 1.7 million t in 1973 and to a further low of 94 000 t in 1984. Since then the stock has been recovering, and the total catches have increased again to 11.9 million t in 1994 (Figure B15.3). Other small pelagics, such as the South American sardine (pilchard), the Chilean jack mackerel, and the chub mackerel (Scomber japonicus), that were producing previously negligible catches (of the order of tens of thousand tonnes per year), started increasing after the Peruvian anchoveta fishery collapsed in 1972-73. Since then, the South American sardine (pilchard) and, more recently, the Chilean jack mackerel, became major components of the total fish production in this area.
The South American sardine (pilchard) is the second contributor to the total production of ISSCAAP Group 35 after the Peruvian anchoveta (Figure B15.3). Catches of the South American sardine increased from less than 10 000 t per year prior to 1970 to 3.3 million t in 1979 and to a maximum of 6.5 million t in 1985. Then catches declined to 1.6 and 1.8 million t in 1993 and 1994 respectively, apparently as a consequence of heavy fishing combined most likely with an environmentally-driven long-term "regime change" in abundance (see also Special Topic section on Global synchrony in fish populations).
Other main species in ISSCAAP Group 35 are the Araucanian herring (Strangomera benticki) and the Pacific thread herring (Ophisthonema libertate). Catches of these species have also been highly variable. The Araucanian herring had two distinguishable periods of high production, one between the mid-1960s and mid-1970s, with peak catches of 159 000 t and 183 000 t in 1971 and 1974, and a more recent one that started in 1989 and a record high catch of 584 000 t in 1991.
The increase in the abundance and distribution range of the Chilean jack mackerel (ISSCAAP Group 34) is also worth mentioning. Prior to 1970 there was no evidence of this stock being so abundant, and the annual catches were hardly over 30 000 t per year (Figure B15.4). However, in the early 1970s this species started to appear consistently as by-catch in local artisanal and industrial fisheries, and then more specialized Chilean, Peruvian and ex-USSR fishing fleets began targeting on it in the mid 1970s and 1980s. Catches increased to almost 4.0 million t by 1990 and to more than 4.2 million t in 1994. Another main small pelagic in this area is the chub mackerel in ISSCAAP Group 37 (Figure B15.4). Catches of this species were in the range of 10 to 30 000 t per year prior to 1970, had a rapid increase to 836 000 t in 1978, to decrease to 79 000 t in 1994.
Although grouped here with the larger highly migratory tunas within ISSCAAP Group 36 (Figure B15.5), the Eastern Pacific bonito (Sarda chiliensis) also used to support an important coastal small pelagic fishery in the area. Catches of this species were on the order of 60 000 t per year in the 1950s and 1960s, with a peak catch of 109 000 t in 1961. Following the collapse of the Peruvian anchoveta (its main food source), catches of Eastern Pacific bonito dropped to 4 300 t in 1976 but are now recovering to almost 50 000 t in 1994. Catches of yellowfin tuna (Thunnus albacares) were also increasing in the area, to 88 000 t in 1990, but then dropped to 53 000 t by 1994. Catches of skipjack tuna (Katsuwonus pelamis) have been variable, between 10 000 t (in 1972) and 69 000 t (in 1992) per year, with 23 000 t in 1994.
|Figure B15.6||Figure B15.7|
A major increase has also been reported in the total catches of squids in ISSCAAP Group 57 (Figure B15.7). Catches of this species group increased from less than 10 000 t prior to 1989 to almost 200 000 t in 1994, mostly due to increased catches by Korean, Japanese and Peruvian fleets. The individual squid species are not always identified in the official catch records from this area but there are indications that most of it is the jumbo flying squid (Dosidicus gigas).
RESOURCE STATUS AND MANAGEMENT
As mentioned before, this area is well known for experiencing large changes in the abundance and species composition of the main exploited fish resources. This tends to have major social and economic impacts at national and regional level and, moreover, since the area is a major contributor to world fish production (almost 22% of the 1994 world marine production came from the Southeast Pacific), the effects of these changes are usually evident even when more general world fisheries trends and projections are considered.
Within the region, the Peruvian anchoveta, the South American sardine and the Chilean horse mackerel complex provide a most striking example of how these changes in abundance and species composition can affect local fisheries and national economies. Within this group the most studied species is the Peruvian anchoveta, and it is estimated that, while highly variable, at times it has reached peak total biomass levels of well over 20 million t. Based on an over-optimistic perception of fish abundance provided by peak non-sustainable catch rates, the fishery expanded rapidly and, during several consecutive years, managed to remove a total annual catch of this single species well in excess of the recommended ceiling of 8 to 9 million t per year, with peak catches of 13.1 and 11.2 million t in 1970 and 1971, just prior to its collapse.
While it is recognized that heavy fishing did play a major role in the collapse of the Peruvian anchoveta fishery in the early 1970s, it is also true that the 1972-73 "El Niño" was a primary cause of recruitment failure and stock decline. The lack of adequate management action to drastically reduce fishing pressure did the rest, contributing to aggravate and prolong the decline. The anchoveta stock was already depleted and catches were already fairly low when the much stronger 1982-83 "El Niño" hit the area. That's why the 1982-83 "El Niño" didn't have such a severe impact on the total regional fish production, although it did reduce the Peruvian anchoveta stock to its historical minimum. The fortunate coincidence of favorable environmental conditions and controlled fishing allowed the stock to recover and catches to increase. The two sub-stocks of Peruvian anchoveta are now reported to be fully to heavily exploited and, given their known high natural variability and poor resilience to heavy fishing, particular monitoring and control measures need to be adopted to prevent overfishing.
The South American sardine (pilchard) is considered to be fully exploited, although it might have been over-exploited in part of its distribution range and had virtually disappeared from some areas. Total biomass and total production of this species has been going down since the mid 1980s, and all seems to indicate that this is due to a combination of heavy fishing and an environmentally-driven long-term "regime change" in overall abundance (see also Special Topic section on Global synchrony in fish populations).
Fishing pressure on the Chilean jack mackerel has been building up fairly rapidly in part of its distribution range and, although fishing in other areas is still limited and total biomass levels are reportedly high, the stock can be considered to be moderately to fully exploited, with increased probability of becoming over-exploited if the expansion of fishing in some areas is not controlled. Due to its extended coastal and oceanic distribution, proper management of this fishery might require some kind of tighter regional cooperation.
The eastern Pacific bonito seems to be recovering and is probably moderately exploited in most of its distribution range. Yellowfin tuna is probably fully exploited, while most of the other tunas and the chub mackerel are moderately exploited. Other small pelagics, such as the Araucanian herring and Pacific thread herring are most likely fully to heavily exploited in most of their distribution range.
Amongst the demersals, the South Pacific hake has also shown large recruitment variability associated with "El Niño" type of changes in environmental conditions. Catches of South Pacific hake have been increasing over the past few years as a consequence of environmental factors and increased fishing pressure, and the stocks are considered to be fully to heavily exploited. Other demersals such as the Patagonian grenadier, the Patagonian hake and some toothfishes and congers are most likely fully to heavily exploited, with some of them giving signs of over-exploitation.
Catches and fishing pressure on squids, particularly on jumbo flying squid, has also been building up rapidly in the area but, due to its ample distribution range, the stock is probably still moderately exploited. Amongst the other invertebrates, tropical as well as more temperate water shrimps tend to be fully to heavily exploited, while sea urchins, clams, scallops and other shellfishes have been over-exploited and even depleted in some areas, while they are moderately or very lightly exploited in other areas.
Except for tunas and other highly migratory species, and for the Chilean jack mackerel prior to 1992, all the main fish stocks in this area are exploited by national fleets operating within their own EEZs or by land-based foreign fleets operating under some kind of licence or fisheries agreement with a coastal state. This to some extent simplifies the assessment and management of fisheries as well as the allocation of responsibilities for the conservation and use of living marine resources in the area. In fact, while there is a more regional approach as far as the assessment and management of tuna fisheries is concerned, all other major fisheries in the area are assessed and managed at national level. Nevertheless, there is a well-established tradition of regional cooperation regarding general fisheries research issues, and coastal states might cooperate with neighboring and/or distant-water fishing countries on a case-by-case basis when dealing with the assessment and management of fish stocks that extend well beyond their own EEZs.
Most of the tuna fisheries in the area are assessed and managed by the Inter-American Tropical Tuna Commission (IATTC) that applies a combined scheme of fishing effort controls, catch quotas and close seasons to regulate fishing in its area of influence, which includes and extends well beyond the north-western part of Area 87. Together with the IATTC, other regional organizations such as the Permanent Commission for the Southeast Pacific (CPPS) and the Latin American Organization for the Development of Fisheries (OLDEPESCA) have been exploring alternatives to modify and expand the existing arrangements for the assessment and management of tunas and other highly migratory species in the wider eastern Pacific area.
The CPPS, of which the four coastal states facing Area 87 are members, plays an active role in dealing with regional marine issues, including coordinating activities regarding regional and international legislation, research and training, oil pollution, environment preservation, oceanography and fisheries. Other international, regional or sub-regional organizations such as the EC, FAO, IATTC and OLDEPESCA also support or have supported regional or sub-regional efforts on research, assessment and management of fisheries in the region.
Most of the main fisheries in the area are under some kind of national fisheries management scheme, although their efficacy and the amount of research and administrative efforts devoted to their implementation vary greatly with the type of fishery and from country to country. Limiting access through fishing licences or fishing permits, the setting of total annual catch quotas, closed seasons, closed areas and limiting the minimum size of fish caught are amongst the most frequent management tools that are used and are frequently combined by national fisheries management authorities to regulate fishing in their areas of influence.