Document(s) 8 de 11

Carlos A. R. M. Araujo-Lima
Instituto Nacional de Pesquisas da Amazônia (INPA)
Manaus, AM, Brazil

Mauro Luis Ruffino
ProVárzea – MMA/IBAMA/PPG7
Manaus, AM, Brazil

CHARACTERISTICS OF THE BASIN

Geography

The Amazon drainage basin covers 7.05 million km² between latitudes 2^o N and 15^o S, occupying approximately 39% of the South American land mass. About 72% of the basin is in Brazil (5.1 million km²).⁵⁸² The basin is so broad that it cuts almost through the whole continent; from it’s far west (Andes Cordillera) to the Atlantic Ocean in the east. The main course of the Amazon River runs approximately parallel to the Equator at 2^o south (Figure 1), changing names at least four times: Ucayali, Amazon, Solimões, Amazon. The river enters Brazil, near the Colombian-Peruvian border, as the Solimões River and changes to the Amazon River after meeting the Negro River. The river in its entirety will be refered to as the Amazon River unless otherwise indicated. The Amazon is currently connected to the Orinoco Basin through the Cassiquiare channel in the Upper Negro River. Menezes (1970) suggested that connections exist between the Amazon Basin and the Paraná Basin through the headwaters of the Madeira River, and in 1995 Ribeiro et al. reported an important watershed divide between the Amazon, São Francisco and Paraná basins in the headwaters of Tocantins River. However, during parts of the Miocene (23 to 5 million years ago) the Orinoco, Paraná and Amazon basins were also connected via a seaway.⁵⁸³

Geology

The basin is composed mainly of four different geological formations. The Central Amazon is made up of weathered, re-deposited Tertiary and Pleistocene sediments of fluvial and lacustrine or perhaps marine origin.⁵⁸⁴ Bordering the Central Amazonian sedimentation zone are two old

⁵⁸² IBGE, 1992

⁵⁸³ Webb, 1995; Rossetti & Toledo, 1998

⁵⁸⁴ Fittkau et al., 1975; Webb, 1995

Precambrian shields: the Brazilian shield in the south and the Guyana Shield in the north, both marked at their edges by cataracts in the rivers. In the most westerly region, the Tertiary zone is replaced by a broad Pre-Andean and Andean zone. Quaternary sediments eroded from these areas are deposited along the Amazon River and some of its tributaries.

Physical Characteristics of the River

The Amazon River has 19 major tributaries, fourteen of which are in Brazil (Figure 1). The Tocantins River is geographically classified by the IBGE (Brazilian Institute of Geography and Statistics) as an independent basin, but since its fish fauna is very similar to that of the Amazon, we consider it here as part of the Amazon Basin.

FIGURE 1. The Amazon basin and its main tributaries

Rainfall is the main source of water in the Amazon Basin. Annual precipitation is higher in the western and eastern edges of the Amazon (> 2400 mm/y) and lower in the Central Amazon.⁵⁸⁵ In sites near Manaus, in the Central Amazon, streams were found to drain 25% of the precipitation directly; leaves intercept another 25% and 50% is transpired by the plants back into the atmosphere.⁵⁸⁶ Approximately 50% of the rainfall thus becomes runoff.

Large rivers are characteristic of the Amazon Basin, but they owe their flow and chemical load to a dense network of streams and small rivers. The streams, the first runoff collectors, vary in density throughout the basin. An area near Manaus, for example, has close to 2 km of stream per km².⁵⁸⁷ Water flow depends on the catchment area, but water storage is generally small and transit times short, so storms create temporary and short-term local floods. The streams of the Brazilian Amazon drain intensely weathered soils and are generally poor in nutrients (black and clear waters), again with variation according to the general categories of the watersheds. Sediment load in the water is usually quite low.

Preliminary surveys suggested that the streams are morphologically diverse. Most studies concentrated on streams of above the fourth order (Horton order). In relatively low-gradient terrain, streams follow meandering courses through flat-bottomed valleys bounded by flooded forest, but in other cases these streams run into steep valleys. The flooded forests of streams and small rivers cover as much as 1 million km² or 14% of the Amazon Basin.⁵⁸⁸ The fish species of commercial value visit streams and small rivers seasonally, but spend most of their time in the larger rivers and their floodplains.

The Amazon River and its main tributaries, including the floodplains, covers 300,000 km².⁵⁸⁹ Seasonally flooded savannahs, in the southern and northern parts of the Amazon, account for another 250,000 km². Therefore, 6% of the basin area is continuously subjected to inundation by medium and large rivers. Aerial and satellite imagery evaluation of the Brazilian part of the Amazon River mainstem and its tributaries revealed

⁵⁸⁵ Salati, 1989

⁵⁸⁶ Salati, 1989

⁵⁸⁷ Junk, 1993

⁵⁸⁸ Junk, 1993

⁵⁸⁹ Junk, 1993

that river channels and lakes occupy approximately 17% and 11% of this area, respectively; the remaining area is periodically inundated floodplain.⁵⁹⁰ Lakes larger than 2 km² make up more than 50% of the total lake area.

Floodplain lakes in the Amazon Basin are not homogeneous. Some were formed in the ancient floodplain as isolated arms of the river, while others are formed by the inundation of valleys by small tributaries that drain highland forest. These tributary lakes have small catchment area and backed up water from the main river controls their flow.

Air temperature in the Amazon Basin ranges from 24 to 32^oC. During the austral-winter, they may drop to 20^oC or lower for a few days.⁵⁹¹ Mean water temperatures in the basin are 27–29^oC, but in shallow and still water they reach over 34^oC.

The mean annual discharge from the Amazon River (including the Tocantins River) is 210,000 m³/s,⁵⁹² whereas the discharge of the Solimões River fluctuates between 70,000 and 130,000 m³/s and the Negro River, the largest Amazon River tributary, flows at between 5,000 and 50,000 m³/s.⁵⁹³ In each section of the river, water level in the floodplain is correlated with river discharge. Water level in the river fluctuates seasonally in a monomodal flood curve (Figure 2), being elevated for 7 months of the year. A gauge installed near Manaus has measured water levels ranging from 13.6 to 29.7 m above sea level (a.s.l.) during the last century. The mean annual water level change is 8 m near Iquitos and 10 m near Manaus; the change is less downriver.

Water levels in the central basin peak, rather predictably, in June, but peak earlier in the west and later in the east (low water levels occur between September and November). The inundation area varies between years, depending on the river water level and also on local rainfall.⁵⁹⁴ Near Manaus, rising water levels can increase the flooded area eight fold.⁵⁹⁵ The floodplain stores considerably more water than the main channel and contributes 30% of the flow of the mainstem, as shown by runoff calculations and isotopic studies.⁵⁹⁶

⁵⁹⁰ Bayley & Petrere, 1989; Sippel et al., 1992

⁵⁹¹ Araujo-Lima & Goulding, 1997

⁵⁹² Richey et al., 1986, 1997

⁵⁹³ Richey et al., 1989

⁵⁹⁴ Sippel et al., 1992

⁵⁹⁵ Melack et al., 1999

⁵⁹⁶ Richey et al., 1989

FIGURE 2. River water level fluctuation in four areas of the Amazon Basin⁵⁹⁷

⁵⁹⁷ Adapted from Barthem & Goulding, 1997. Note: Iquitos River baseline for water levels differs from the Brazilian baseline.

Water Characteristics

Amazon tributaries often have extensive drainage basins with a variety of different soils, and thus they have a range of different sediment loads and dissolved ion contents. Gibbs (1967) correlated these characteristics with the relief and the type of soil in the basins.

Stallard and Edmond (1987) further detailed the chemical analysis of tributary waters and found that alkalinity, silica and two anion concentrations (Cl + SO₄) accounted for 99% of the variation in major dissolved ions of their waters. These three features are associated with soil weathering and chemical transport and can broadly place the rivers into four classes (Table 1):

1. Rivers that drain the most intensely weathered soils, such as the tertiary sediments, show high levels of Fe, Al, H and very low concentration of anions, and are relatively enriched in silica;
2. Rivers that drain siliceous terrain, such as the Brazilian and Guyana Shields;
3. Rivers that drain marine sediments or red bed, a type of sedimentary rock, with high cation concentrations, minor evaporites, carbonates and reduced shales. These exhibit high levels of Ca, Mg, alkalinity and occasionally SO₄ (when draining areas with shale).
4. Rivers that drain massif evaporites enriched in Na and Cl (rock originating from evaporated seawater).

An older classification of Amazonian rivers based on the water surface colour⁵⁹⁸ correlates roughly with this grouping scheme. “White water” rivers are alkaline with high sediment loads, and correlate with classes 3 and 4. “Clear water” rivers correspond to class 2 and “black water” rivers to class 1.

The dark colour of black water rivers is not related to geochemical processes, but rather to a heavy load of dissolved organic compounds (humic and fulvic acids). The humic material is produced in sandy soils (podzols), occurring mainly in campina and igapó forests (sparsely vegetated forest and flooded forest of black water rivers, respectively).

⁵⁹⁸ Wallace, 1853; Sioli, 1968

These have a surface humus layer, a bleached quartz horizon up to several meters thick and an underlying aluminous clay lens cemented with humic material.⁵⁹⁹ The soils are highly acidic and generally wet, which results in the slow decay of the organic matter and allows continual leaching of humic material. The concentration of humic acid is over five times higher in black water rivers, such as the Negro and Jutaí rivers, than in the rivers with high sediment load, such as the Amazon, Juruá or Purus rivers. The

TABLE 1. Characteristics and classification of major Amazon tributaries and the Amazon mainstem⁶⁰⁰

⁵⁹⁹ Leenheer, 1980

⁶⁰⁰ data marked with¹ are Martinelli et al. 1989a, 1989b;² are from Forsberg et al., 1988; all else from Stallard & Edmond, 1987. W=white water, B=black water, C=clear water, Q= mean discharge, TSS= mean total suspended solids, TZ+= total cations, ALK= alkalinity. See text for river classification details.

fine sediment particles in these latter rivers adsorb and neutralize the dissolved humic acids.⁶⁰¹

The input of nutrients to the floodplain depends largely on the water the floodplains receive. Rivers with high sediment load and high alkalinity, such as classes 3 and 4 in Table 1, have higher concentrations of nitrogen and soluble reactive phosphorus than rivers that drain the tertiary and siliceous sediments (black and clear water or classes 1 and 2).⁶⁰²

Floodplains have two main water sources: the main river, and streams draining upland areas. Floodplains on islands in the river typically have small local catchment areas and are generally dependent on river water throughout the year. Nutrient inputs from most upland streams are very low because they drain the upland tertiary sediments, so the river water regulates floodplain fertility. In white-water floodplains where mainstem river water is alkaline and stream run-off is acidic, Forsberg et al. (1988) used alkalinity as an indicator of the source of the water in floodplains. In this manner, they showed that during high water the floodplain contains mostly water from the river, whereas during low water stream inputs to floodplain lakes dominated (depending on the ratio of the area of the lake to the area of the local drainage basin).

Social Aspects of the Basin

Although the numbers are disputed, the human population of the basin before 1500 is estimated to have been between 0.5 to 5 million people.⁶⁰³ The population density was especially high in the Amazon floodplain (15 people/km²), but the indigenous population was decimated very early upon contact with Europeans and little is known of its culture. The first European voyagers, who traded with local populations to obtain food, noticed the abundance of fish, turtles and other game in the basin.⁶⁰⁴

The human population of the Brazilian Amazon has grown to 11 million over the last 500 years.⁶⁰⁵ Average population density in this region is only 2.2 inhabitants per km², but 55% of the population is highly aggregated in 40 cities of more than 50,000 inhabitants.

⁶⁰¹ Ertel et al., 1986

⁶⁰² Forsberg et al., 1988

⁶⁰³ Carneiro da Cunha, 1998

⁶⁰⁴ Porro, 1998

⁶⁰⁵ IBGE, 1992

People fish intensively in the Amazon, not just as full-time professionals or for sport, but also as part-time employment or to supplement their diet. One reason for this is the proximity to large water bodies and the abundance of fish. Many farmers living on river banks, for example, have properties that include lakes or share floodplain lakes with their neighbours, so fresh fish can be caught only a few meters away from home.

Habitats Used by Migratory Species

The main habitats used by migratory fishes are the river and its floodplain. Migratory catfish, with the exception of Hypophthalmus spp., concentrate in the river channels and estuary. The caracids migrate and spawn in the river channels but feed mostly in the floodplain. Floodplain habitats can be divided into three main mesohabitats: the open water of lakes, herbaceous vegetation and flooded forests. Herbaceous plants depend on high nutrient input, so in rivers with black and clear waters, such as the Negro River, this mesohabitat is much less developed.

Light penetration and nutrient input drive the algal primary production of habitats. The Amazon River and most silty tributaries are turbulent and turbid with a euphotic zone of less than 1 m, so phytoplankton production is almost nil. The floodplain, however, contributes part of its primary production to the river when waters are receding. Tributaries with low sediment loads have higher light penetration and support more primary production.⁶⁰⁶ In floodplains the euphotic zone

FIGURE 3. Existing and planned reservoirs in the Amazon Basin⁶⁰⁷

⁶⁰⁶ Putz & Junk, 1997

⁶⁰⁷ Adapted from Fearnside, 1995

increases up to four meters as suspended solids settle out.⁶⁰⁸ Plankton production is high in this habitat, particularly in rivers receiving nutrient-rich water. The flooded forest, with its easily accessible litter, plays an important role in supplying carbon to the food chain.

Another type of habitat in the Amazon Basin are man-made lakes. There are presently four large and three small reservoirs in the Brazilian Amazon, and a further 75 are planned.⁶⁰⁹ The total area of the existing reservoirs is 5,700 km², just under 0.01% of the whole basin (Figure 3). If all 75 planned projects are implemented the total area will rise to approximately 114,000 km².⁶¹⁰

MIGRATORY SPECIES AND MIGRATION PATTERNS

Catfish (Siluriformes)

Brachyplatystoma vaillantii

This fish is known as the piramutaba, pira-botão, and mulher ingrata in Brazil, pirabutón in Colombia and manitoa in Peru. It was described by Eigenmann and Eigenmann (1890) and commented on by Britsky (1981).

B. vaillantii occurs mainly along the mainstem of the Amazon River and its Andean and sub-Andean white water tributaries in the Brazilian, Peruvian and Colombian Amazon, as well as in the Orinoco and Maroni rivers (French Guiana). It is rarely found above rapids, except in the Madeira River,⁶¹¹ and above the Middle Tocantins River.⁶¹²

The fish is a medium sized riverine piscivore (max. 100 cm)⁶¹³. It rarely visits the floodplain, preferring to inhabit the mainstem of the rivers.⁶¹⁴ Its migration has been investigated by tagging, field observation and fishery studies. Tagging conducted during the late seventies failed to produce any useful results, probably due to the large distances involved.⁶¹⁵

⁶⁰⁸ Putz & Junk, 1997

⁶⁰⁹ Fearnside, 1995

⁶¹⁰ Fearnside, 1995

⁶¹¹ Lauzanne et al., 1990

⁶¹² Leite, 1993

⁶¹³ SL = standard length: length from tip of nose to end of vertebral column

⁶¹⁴ Barthem & Goulding, 1997

⁶¹⁵ Godoy, 1979

Fishery reports and field observations suggest that this species migrates 3,500 km upriver from the mouth of the Amazon River to spawn in Andean tributaries (400 m altitude), such as the Ucayali and Japurá rivers.⁶¹⁶

Newly hatched larvae (< 10 mm) have not been found. However, large larvae and young juveniles (13–30 mm)⁶¹⁷ have been caught in the mainstem of the Amazon River, near Manaus and Tefé and near the mouth of the Xingú River.⁶¹⁸ Near Manaus, these juveniles were found at depths of 10–20 m, but only during the low water season, between September and November. None were observed during the high water season between March and July.⁶¹⁹ Juveniles less than 40 mm in length thus live in the mainstem and estuary of the Amazon, but large size classes (50–150 mm) have been found only in the estuary. Adults have been found throughout the Amazon River and its white water tributaries, but there are few accounts of sexually mature fish. Only a few mature females have been reported in the Solimões River near Tefé and in the Japurá River (the Caquetá River in Colombia).⁶²⁰

Upstream migration occurs between May and October. In the estuary B. vaillantii avoids salt water and during the low water season when the freshwater recedes, the fish move to the inner estuary.⁶²¹ During all life stages piramutaba lives primarily near the river bed.

Landings – Landings for B. vaillantii, which represent the longest fisheries time series for the Amazon Basin, were measured by SUDEPE beginning in the early 1970s. Currently, different institutions in Pará, including the Museu Paraense Emilio Goeldi in Belém, are collecting the data, which are then compiled by IBAMA.⁶²² Statistics in Pará State (> 70% of the catch) are relatively easy to collect because a relatively small fleet of large boats with few landing points carries out the fishery. The situation in other areas of the basin is less organized and only recently have landings begun to be monitored.

Piramutaba is the main fish caught, by weight, in the Amazon since the 1970s (Figure 4). Landings increased after 1972, peaking at

⁶¹⁶ Barthem & Goulding, 1997

⁶¹⁷ FL = Fork length, length from tip of nose to fork of tail

⁶¹⁸ Barthem, 1984; Barletta, 1995; Barthem & Goulding, 1997

⁶¹⁹ Barletta, 1995

⁶²⁰ Barthem & Goulding, 1997

⁶²¹ Barthem & Goulding, 1997

approximately 29,000 tons in 1977. They decreased irregularly until 1992, but have since recovered to 20,000 ton/y (Figure 4). Because approximately 30% of the industrial fleet catch is rejected, it has been suggested that the total catch has been higher and in 1977 reached 32,000 tons.⁶²³ Effort, however, has been increasing, and therefore catch per unit effort (CPUE) has been consistently decreasing.

This species is considered to be overexploited.⁶²⁴ Indications of overexploitation are the high catch-to-biomass ratio of trawls in the estuary and the decreasing size of landed fish. The maximum sustainable yield calculated using the Schaeffer model from two sources were 19,929 tons/y and 20,900 tons/y, with a maximum effort of 48 boats and 5,900 days, respectively.⁶²⁵ Both figures have been surpassed often in the last 25 years, which has always resulted in a subsequent decrease in the landings (Figure 4).

Brachyplatystoma filamentosum

B. filamentosum is known in Brazil as piraíba or filhote (for individuals less than 80 kg), as zúngaro salton in Peru and as pirahiba, lechero or valentón in Colombia. It is a very large riverine piscivore (max. 300 cm), distributed through the whole Amazon Basin, including nutrient-poor tributaries of the Amazon River, the Tocantins and Araguaia rivers and the estuary.⁶²⁶ Young juveniles of B. filamentosum were reported in the mainstem of the Amazon and Negro rivers.⁶²⁷ Large juveniles and adults are found mostly in the mainstem of rivers and visit the floodplain only occasionally.⁶²⁸ The migration pattern of B. filamentosum is not known.

Landings – Filhote is an important catfish in the fishery of Amazonas State. Average filhote landings between 1994 and 1996 in Manaus market were 4 tons/y.⁶²⁹ Rezende (1998) reported a mean landing of 300 tons/y of filhote in seven fish-packing plants near Manaus, suggesting that Manaus harbour took in only 1% of the total landings in 1995 and 1996.

⁶²² Dias Neto & Mesquita, 1988; IBAMA, 1997, 1998, 1999; Anonymous, 1999

⁶²³ Anonymous, 1999

⁶²⁴ Anonymous, 1999

⁶²⁵ IBAMA, 1997; Anonymous, 1999

⁶²⁶ Barthem & Goulding, 1997

⁶²⁷ Barletta, 1995; Garcia, 1995

⁶²⁸ Zuanon, 1990

⁶²⁹ Batista, 1998

FIGURE 4. Long-term trends in yearly landings of representative fisheries products 1972–1998⁶³⁰

This confirms earlier expectations⁶³¹ that landings in Manaus are a small fraction of the total landings for filhote. However, figures from the packing plants have only recently been sampled and no reliable time series are available. In Santarém, filhote landings reached 150 tons/y in 1993.⁶³² The fish is relatively less important in Pará.⁶³³

Brachyplatystoma flavicans

B. flavicans is known as the dourada in Brazil, zúngaro dourado in Peru and dorado or plateado in Colombia.

⁶³⁰ Piramutaba landings refer to Belém (Anonymous, 1999) and other products to Manaus (Mérona & Bittencourt, 1988; Batista, 1998)

⁶³¹ Bayley & Petrere, 1989

⁶³² Ruffino et al., 1998

⁶³³ IBAMA, 1998, 1999

The species is also a large riverine piscivore (max. 180 cm) that occurs in the Amazon River, from its estuary to its headwaters, including the tributaries of the Negro River, the Madeira River, the Tocantins River and others.⁶³⁴ A very similar species or perhaps the same is found in the Orinoco River.⁶³⁵

Young juveniles (6 cm) have been found in the mainstem of the Amazon River,⁶³⁶ and older juveniles (19–96 cm) were reported in the estuary,⁶³⁷ where they occupy the upper strata of the water column. Large juveniles and adults (38–144 cm) are found in the mainstem and lower reaches of the tributaries, but the largest fish were reported only in the headwaters of tributaries and the Western Amazon.

The migration of the dourada is still poorly known. Barthem and Goulding (1997) hypothesized that schools of juveniles leave the estuary (the nursery ground) and disperse for two years in the Central Amazon where they feed and grow. After this period in the river channels the fish migrate upstream to spawn in the headwater of the Amazon River, the Madeira River, the Japurá River and other tributaries. The larvae drift downriver to the estuary.

Landings – Dourada is an important fish in the Amazonian fisheries statistics, and is landed especially in Pará State, where it reached over 5000 tons in 1998. Landings in Manaus in the same year were 1800 tons and in other cities such as Tefé, Manacapurú and Itacoatiara were negligible.⁶³⁸ In Amazonas State, Rezende (1998) registered total landings in six fish-packing plants of 798, 929 and 1,155 tons in 1995, 1996 and 1997, respectively. This suggests a slight increase during this period. Catch per unit effort varied from 9 to 64 kg/fisher/day. Increased landings have also been reported in Santarém, Pará State. The figures jumped from 482 tons in 1992 to 793 tons in 1999.⁶³⁹ However, values for the Belém market, probably the most important port for dourada, are not yet available.

⁶³⁴ Garcia, 1995; Goulding, 1980; Leite, 1993; Barthem & Goulding, 1997

⁶³⁵ Garcia, 1995; Goulding, 1980; Leite, 1993; Barthem & Goulding, 1997

⁶³⁶ Barthem & Goulding, 1997

⁶³⁷ Barthem & Goulding, 1997

⁶³⁸ SUDEPE, 1986; Barthem, 1999; Bittencourt, 1999

⁶³⁹ Unpublished data from Projeto lara/IBAMA

Hypophthalmus spp.

Popular names for Hypophthalmus spp. in Brazil are mapará and mapará bico de pena, which refer to at least three species: Hypophthalmus edentatus, H. marginatus and H. fimbriatus. The three species are medium size planktivores (max. ~40 cm).

Hypophthalmus species are found in the Amazon River and its tributaries, but have not been reported in the upper part of some tributaries, such as the Trombetas,⁶⁴⁰ Negro⁶⁴¹ and Juruá rivers.⁶⁴² A fourth species, H. perperosus, has been reported in the Tocantins and Araguaia rivers, but is probably H. edentatus.

Adults and juveniles of H. edentatus, H. fimbriatus and H. marginatus were sampled near the bottom of the Amazon and Negro rivers during most of the year, but are more abundant in the open water habitats of the floodplain.⁶⁴³ Larvae of Hypophthalmus spp. were found drifting in the Amazon River in the flood season and also in floodplain lakes, including those of nutrient-poor rivers. Barletta (1995) reported larvae and juveniles in the Amazon and Negro rivers during the flood season (December to June), but only in the Negro River during the high and receding water season (July to September). Garcia (1995) mentioned high densities of juveniles in a floodplain lake of the Negro River in May. Juveniles have not been found among the macrophytes of the floodplain of the Amazon River;⁶⁴⁴ they may occupy the open water of the lakes, which have not been sampled for all size classes.

Carvalho and Mérona (1986) studied the size distribution and movements of H. marginatus in the Lower Tocantins River before the filling phase of Tucuruí Reservoir and made inferences about its migration. They found young fish in the mouth, and adults in the Middle Tocantins River in January and February, in relatively homogeneous schools. Between March and October (the low water period) the schools of young fish swim upstream to the Middle Tocantins River, where they disperse. In November, maturing fish migrate upstream from the Middle Tocantins

⁶⁴⁰ Ferreira, 1993

⁶⁴¹ Goulding et al., 1988

⁶⁴² Silvano et al., 2000

⁶⁴³ Carvalho, 1980a, 1980b; Garcia, 1995

⁶⁴⁴ Sánchez-Botero, 2000

River and spawn near the rapids in January and February. The eggs and larvae are believed to drift downriver to the mouth of the Tocantins River.

Landings – Mapará landings have only recently been reported. In seven fish-packing plants near Manaus, landings averaged approximately 400 tons/y between 1995 and 1997.⁶⁴⁵ In Santarém, Pará State, landings were 810 tons in 1993.⁶⁴⁶ Data for Belém were not available, but IBAMA reported landings ranging from 2,400 to 3,100 tons/y.⁶⁴⁷

Pseudoplatystoma spp.

This group of species is generally known as surubim in Brazil, but in the Amazon Pseudoplatystoma fasciatum is surubim (max. 110 cm) and P. tigrinum is caparari (max. 130 cm). Both species are usually grouped in the landing reports as surubim. For convenience we will consider them together. Other names are surubim lenha or surubim tigre in Brazil, pintado, rayadao, pintadillo or bagre tigre in Colombia, and zúngaro doncella or zúngaro tigre in Peru.

Both species are piscivores and widely distributed in the Amazon Basin, excluding the estuary. P. tigrinum seems more concentrated in the lower reaches.⁶⁴⁸ There are few accounts of larval distribution and juveniles. Adults have been found in the floodplains and in the mainstem of the Amazon River and tributaries.⁶⁴⁹ The migration pattern of both species is unknown.

Landings – Pseudoplatystoma is an important catfish in the landing statistics of Amazonas State. The landings of surubim in Manaus market averaged less than 100 tons/y between 1986 and 1996 (Figure 4). Rezende (1998) reported a mean landing of 700 tons/y of surubim in seven fish-packing plants near Manaus, suggesting that Manaus harbour took in only 10% of the total landings in 1995 and 1996. However, figures from the packing plants have only recently been sampled and no reliable time series is available. In Tefé, surubim landings averaged 18 tons/y between 1991 and 1994.⁶⁵⁰

⁶⁴⁵ Rezende, 1998

⁶⁴⁶ Ruffino et al., 1998

⁶⁴⁷ IBAMA. 1996, 1997, 1998, 1999

⁶⁴⁸ Lauzanne et al., 1991; Barthem & Goulding, 1997

⁶⁴⁹ Zuanon, 1990; Mérona & Bittencourt, 1993

⁶⁵⁰ Barthem, 1999

In Santarém, surubim reached 500 tons/y in 1993.⁶⁵¹ The fish is relatively less important in Pará.⁶⁵² The average landing of P. tigrinum, which represents 6% of the total landing in Santarém, was 215 tons between 1992 and 1996.⁶⁵³ The average catch per unit effort (CPUE) was 3.7 kg/fisher/day. The same authors, using a yield per recruit model, considered this species to be overexploited.

Characids

Brycon spp.

Brycon spp. are called matrinxã, matrinchã, matrinchão, jatuarana, and piracanjuba in Brazil, and sábalo in Peru.

The matrinxã is distributed throughout the Amazon Basin, comprising at least eight species in the Amazon⁶⁵⁴ with unresolved taxonomic controversy. The present chapter uses taxonomy outlined in two relatively recent reviews of the genus,⁶⁵⁵ but readers consulting the scientific reports will not always find the same nomenclature and distribution.

Brycon cephalus (max. 46 cm) is perhaps the most abundant species of matrinxã in the mainstem of the Amazon River and is the most studied. The other species in the mainstem are B. melanopterus (max. 28 cm), also known as jatuarana, B. erythropterus, which lives in the Peruvian Amazon, and Brycon sp., which occurs only in the Madeira River.⁶⁵⁶ Both are smaller than B. cephalus, B. brevicauda, B. carpophagus and B. falcatus (max. 35 cm), which were reported in the Tocantins River and its tributaries, the Araguaia and Branco rivers.⁶⁵⁷ B. pesu, a species listed in inventories of the Trombetas River and Branco River ⁶⁵⁸ may not be a distinct species,⁶⁵⁹ but is also less important to fisheries. All species are omnivores/frugivores.

The larvae of B. cephalus are found in the mainstem of the Amazon River, and possibly in other high-nutrient tributaries.⁶⁶⁰ Juveniles live in

⁶⁵¹ Ruffino et al., 1998

⁶⁵² IBAMA, 1998, 1999

⁶⁵³ Ruffino & Isaac, 1999

⁶⁵⁴ Howes, 1982; Géry, 1977; Géry & Mahnert 1992

⁶⁵⁵ Howes, 1982; Géry & Mahnert, 1992

⁶⁵⁶ Géry & Mahnert, 1992

⁶⁵⁷ Costi et al., 1977; Ferreira et al., 1998; Leite, 1993

⁶⁵⁸ Ferreira et al., 1988; Ferreira, 1993

⁶⁵⁹ Howes, 1982; Géry & Mahnert, 1992

⁶⁶⁰ Moura, 1998; Leite, 2000

the adjacent floodplain, mostly under the floating macrophytes. Adults are distributed throughout the floodplains, including the flooded forests of white and black water rivers.

The migration of this species is complex, apparently similar to that of Semaprochilodus spp.⁶⁶¹ Near Manaus, B. cephalus joins multi-species schools and migrates downriver from the Negro River to spawn in the Amazon River in December and January, as water levels there begin to rise.⁶⁶² A similar pattern was also observed for Brycon sp. in the Madeira River.⁶⁶³ The embryos and larvae develop while drifting in the Amazon River, and probably get washed into the white water floodplains.⁶⁶⁴ After spawning (February to March) the adult fish return to the black-water tributaries. Later in the year (May to August) these fish move downstream again from the Negro River or other nutrient-poor tributaries into the Amazon or Madeira rivers, where they remain until the end of the wet season in September. At this time, they move upstream again to the next nutrient-poor tributary and into forest streams, where they spend the dry season ⁶⁶⁵ before the next spawning migration.

The migratory movements of other Brycon species are less known. Borges (1986) suggested that B. melanopterus does not migrate downriver to spawn.

Landings – Matrinxã are important in landings in Manaus, varying from 500 to 5,100 tons in recent decades (Figure 4), and with a general increase since the 1970s.⁶⁶⁶ In Tefé landings of matrinxã averaged 26 tons/y in 1992, 1993 and 1994.⁶⁶⁷ During 1997 landings of matrinxã in three cities (Manacapuru, Itacoatiara and Parintins) totalled 60 tons.⁶⁶⁸

Colossoma macropomum

C. macropomum is known as tambaqui in Brazil, gamitana in Peru, pacu in Bolivia, and cachama or cachama negra in Colombia. This species is

⁶⁶¹ Petrere, 1985a

⁶⁶² Borges, 1986; Villacorta Correa, 1987

⁶⁶³ Goulding, 1979, 1980

⁶⁶⁴ Araujo-Lima, 1990

⁶⁶⁵ Goulding, 1979; Borges, 1986; Villacorta-Correa, 1987

⁶⁶⁶ Petrere, 1978b; Mérona & Bittencourt, 1988; Batista, 1998

⁶⁶⁷ Barthem, 1999

⁶⁶⁸ Bittencourt, 1999

widely distributed throughout the Brazilian Amazon, and is most abundant west of the Xingú River. It is found up to the headwaters of the nutrient-rich Madeira, Juruá, Purus and Içá rivers but seems restricted to the lower 300 km in nutrient-poor rivers.⁶⁶⁹ It is a rather large omnivore/ frugivore fish (max. ~110 cm).

Larvae were reported in the Amazon River mainstem at the beginning of the flood season. However, young juveniles (10 cm) were found in the floodplain of other white water rivers, suggesting that larvae are also present in other nutrient-rich rivers such as the Purus and Madeira rivers.⁶⁷⁰ Juveniles live under the aquatic macrophytes, which grow in the floodplains. Larger juveniles (greater than 30 cm), small juveniles and adults are all found in flooded forest during the flood season. However, juveniles stay in the floodplain during low water season, when adults leave for the adjacent river.⁶⁷¹ In the headwaters of the Madeira River juveniles and adults have been reported in flooded forests and in savannahs similar to those reported in the Orinoco Basin.⁶⁷²

The migration of tambaqui differs slightly from that of other characids (Figure 5). The adults feed in the forest during high water. As the water recedes the tambaqui migrate to the river where they remain until high water returns. They then slowly move upstream in schools and hide between fallen trees along woody shores until the spawning season (November to February). After spawning the fish stay in the river until the water floods the forest. Spawning seems to occur along the woody shores of nutrient-rich rivers,⁶⁷³ and larvae drift in the river until transported to the adjacent floodplain. The pattern described in the Guaporé River, a tributary of the Madeira River, is similar.⁶⁷⁴

Landings – Schools of tambaqui are now hard to find in the river. The tambaqui fishery was very important in the 1970s, but landings in Manaus have decreased markedly from 15,000 tons/y in 1972 to 800 tons/y in 1996 (Figure 4). Tambaqui is especially important in Amazonas State, where it fetches top market prices. INPA and the University of Amazonas

⁶⁶⁹ Araujo-Lima & Goulding, 1997

⁶⁷⁰ Araujo-Lima & Goulding, 1997

⁶⁷¹ Araujo-Lima & Goulding, 1997; Costa, 1998

⁶⁷² Loubens & Panfili, 1997

⁶⁷³ Costa et al., 1999a, 1990b

⁶⁷⁴ Loubens & Panfili, 1997

FIGURE 5. Reproductive migration of tambaqui (Colossoma macropomum) in the Central Amazon⁶⁷⁵

(FUA) in Manaus have therefore actively monitored its landings. The main market for tambaqui is Manaus; however, the landing sites are now dispersed throughout the city, making data collection difficult. The catches are landed not only by the fishing fleet, but also by other boats hired by middlemen, who sell directly to city supermarkets and restaurants outside the catch area.⁶⁷⁶ It is difficult therefore to know if the recent and extremely low reported landings reflect the actual catch.

Despite the problems associated with statistics, there is no doubt that the stock has been overexploited. Using different methods Petrere (1983) and Mérona and Bittencourt (1988) both reached similar conclusions in the early 1980s. Most fish currently landed are juveniles;⁶⁷⁷ and although catches were already low in 1985, fishing effort has not been reduced even though CPUE has fallen. Mérona and Bittencourt (1988) tried without success to estimate the MSY for this species.

Piaractus brachypomus

P. brachypomus is known as pirapitinga in Brazil, as paco in Peru or cachama blanca in Colombia. It was formerly considered part of the Colossoma

⁶⁷⁵ Figure extracted from Araujo-Lima & Goulding, 1997

⁶⁷⁶ Araujo-Lima & Goulding, 1997

⁶⁷⁷ Araujo-Lima & Goulding, 1997

genus. Britski (1977) and Géry (1977) reviewed the species. Pirapitinga is a large herbivore (max. ~80 cm) distributed widely in the Amazon, Tocantins and Araguaia rivers and their main tributaries, including those poor in nutrients. It is also found above the rapids of these tributaries.⁶⁷⁸ Pirapitinga occurs in the Orinoco Basin as well.⁶⁷⁹

Very little is known about the larvae. Juveniles are found in the floodplain of nutrient-rich rivers, often between the roots of aquatic macrophytes. Adults live in the flooded forest of the Amazon River and its nutrient-rich tributaries, but are also found in the headwaters of nutrient-poor tributaries.

The migration of the pirapitinga is not well known. Goulding (1979) suggested that it is similar to that of other migratory characins.

Landings – Pirapitinga landings in Manaus have varied from 200 tons/y to 2,900 tons/y between 1976 and 1996, but with no clear trend (Figure 4).

Mylossoma spp. and Myleus spp.

Mylossoma are known as pacu, pacu comum, pacu caranha, pacu manteiga or pacu branco in Brazil. In Venezuela the fish is called palometa. There are actually two species: Mylossoma duriventre and Mylossoma aureum. Other species, such as Myleus schomburgki, Myleus torquatus and Myleus rubripinnis are occasionally marketed under this name, but in small quantities. M. schomburgki is also known as pacu mula. The other species are normally referred to as just pacu.

M. duriventre (max. 25 cm) and M. aureum (max. 20 cm) are omnivores distributed throughout the Amazon Basin, including the Amazon River, its main nutrient-rich tributaries, and the Tocantins and Araguaia rivers. They also occur in the lower reaches of nutrient-poor tributaries. The larvae of Mylossoma spp. have been reported drifting in the Amazon River.⁶⁸⁰ Juveniles live under the floodplain macrophytes of the Amazon River,⁶⁸¹ while adults live in the flooded forest. ⁶⁸²

Migration patterns have not been completely worked out, but seem similar to the patterns of other migratory characids like Brycon spp. At

⁶⁷⁸ Goulding, 1980; Lauzanne et al., 1990

⁶⁷⁹ Oliveira & Araujo-Lima, 1998

⁶⁸⁰ Nascimento, 1992; Araujo-Lima, 1994; Oliveira & Araujo-Lima, 1998

⁶⁸¹ Sanchez-Botero, 2000

⁶⁸² Goulding, 1979

the beginning of the flood season, adults migrate from floodplain lakes to the Amazon and Madeira rivers, where they spawn.⁶⁸³ The same migration presumably occurs in other nutrient-rich tributaries. Larval fish drifting in the rivers for a few days are carried to the floodplains where they develop. After spawning, adults return to the floodplain and disperse into flooded forests when they become accessible. There they feed until the low water period, whereupon they migrate to nutrient-rich rivers, swimming upstream to the next tributary or floodplain lake.

Myleus spp. are common in nutrient-poor tributaries, and less frequent in white water rivers. The movements of Myleus spp. have been less studied, but these species seem not to migrate to nutrient-rich water to spawn.⁶⁸⁴ Juveniles of Myleus spp. have been reported in the floodplains of the Negro River.⁶⁸⁵

Landings – Manaus landings averaged 3000 tons/y in the 1994–1996 period. In Tefé (1992–1994) the mean catch was 73 tons/y.⁶⁸⁶ During 1997, landings of pacu in three cities (Manacapuru, Itacoatiara and Parintins) totalled 360 tons.⁶⁸⁷ Data for Santarém in Pará State from 1993 show landings of 102 tons.⁶⁸⁸

Semaprochilodus spp.

Semaprochilodus spp. are known as the jaraqui in Brazil, and as yarachi in Peru and Colombia. Three species occur in the Brazilian Amazon: Semaprochilodus insignis, S. taeniurus and S. brama.⁶⁸⁹

This genus occurs only in the Amazon and Orinoco basins and in some rivers of Guyana.⁶⁹⁰ S. insignis (max. 36 cm) and S. taeniurus (max. 35 cm) are widespread in the basin, occurring in most of its tributaries, but apparently not in the Xingú and Tapajós rivers. S. brama (max. 40 cm) occurs only in the Tocantins, Araguaia and Xingú rivers. All three species are detritivores.

⁶⁸³ Goulding, 1979

⁶⁸⁴ Goulding, 1979, 1980

⁶⁸⁵ Araujo-Lima et al., 1986

⁶⁸⁶ Barthem, 1999

⁶⁸⁷ Bittencourt, 1999

⁶⁸⁸ Isaac & Ruffino, 1996

⁶⁸⁹ Castro, 1990

⁶⁹⁰ Castro, 1990

Recently-hatched larvae of S. insignis and S. taeniurus have been reported drifting in the Amazon River.⁶⁹¹ Juveniles of S. insignis and S. taeniurus were found in the floodplains of the Amazon River.⁶⁹² Adults and older juveniles of both species live mainly in black and clear water rivers,⁶⁹³ where they are found in flooded forests, the main channel of the rivers and their tributaries, sandy beaches, floodplain lakes and forest streams. S. taeniurus prefers sandy beaches while S. insignis prefers streams. Both species are also found, at least temporarily, in white water rivers and floodplain lakes.

S. taeniurus and S. insignis migrate twice a year.⁶⁹⁴ They undertake spawning migrations at the beginning of the flooding season, moving out from nutrient-poor tributaries (black and clear waters) downstream towards turbid-water rivers (white water) to spawn. S. taeniurus, in general, starts its migration before S. insignis. Spent fish return to the flooded forest of the same poor water tributary, where they feed for three to four months. Dispersal migration occurs in the middle of the floods when the fish descend from nutrient-poor tributaries once more and migrate upstream in nutrient-rich rivers, entering and successively leaving other tributaries until the low water season. When the water level starts to rise again the fish spawn in the mouth of the last nutrient-poor tributary entered. Ribeiro and Petrere (1990) suggest that jaraqui living in the upper reaches of tributaries are older and do not migrate, but they did not propose the age limit for migration. The non-migratory jaraqui are much larger than the migrating fish.

The migration pattern of S. brama in the Tocantins River and in the Middle and Upper Araguaia rivers differs from those of the two species described above.⁶⁹⁵ These fish migrate upstream from lakes and the main channel at the beginning of the flood. During the migration their gonads mature and they spawn in the floodplains of the headwaters. After spawning they move downstream and spread into the flooded forests. When the water recedes they return to the main channel.

⁶⁹¹ Nascimento, 1992; Araujo-Lima, 1994

⁶⁹² Bayley, 1983; Araujo-Lima & Hardy, 1987; Fernández, 1993

⁶⁹³ Ribeiro & Petrere, 1990

⁶⁹⁴ Goulding, 1980; Ribeiro & Petrere, 1990

⁶⁹⁵ Ribeiro et al., 1995

Landings – Jaraqui (S. taeniurus, S. insignis) are the second most-captured fish in the Amazon over the last two decades. Their total catch was difficult to measure due to the fragmentation of the landings over several ports, but was estimated in 1998 as 9,700 tons/y (Figure 4). The maximum landings in Manaus Central Harbour, the largest port of Amazonas State, was approximately13,000 tons/y in the mid-1980s. If one assumes landings of this harbour represent approximately 50% of the total Amazonian landings (Figure 6), then the maximum catch in this period would be 26,000 tons/y. Landings have been decreasing since then, and in 1996 they had dropped to approximately 7,000 tons/y in Manaus harbour (Figure 4)⁶⁹⁶ and 10,247 tons/y in the whole Amazon.⁶⁹⁷

FIGURE 6. Landings of representative characids⁶⁹⁸ in Manaus relative to the whole Amazon basin⁶⁹⁹

Mérona and Bittencourt (1988) applied the Schaeffer model to jaraqui data and estimated a maximum sustainable yield (MSY) of 11,000 tons/y for an effort of 84.4 fisher/day, a yield reached only in 1985. Their estimation must be considered carefully because it was based on the yield of only part of the fishing fleet.

⁶⁹⁶ Batista, 1998

⁶⁹⁷ IBAMA, 1997

⁶⁹⁸ matrinxã, jaraqui, pacu, curimatã and pirapitinga landings. Each circle represents one species in 1995 or 1996.

⁶⁹⁹ The dashed line indicates Manaus landings if it was equal to 50% of basin’s landings (Batista 1998; IBAMA 1996, 1997).

Average landings in other cities of Amazonas State were 250 tons/y in Tefé (1991–1994),⁷⁰⁰ 500 ton/y in Itacoatiara (1996–1997), and 150 tons/ y in Parintins and Manacapuru (1996–1997).⁷⁰¹ In Santarém, Pará State, the landing was 185 tons in 1993.⁷⁰²

There were no official fisheries statistics for S. brama in the Tocantins River,⁷⁰³ but Costi et al. (1977) noticed that this species was relatively abundant in the fish assemblage of this river.

Prochilodus spp.

Popular names for these detritivore species are curimatã in Brazil, boquichico in Peru, sábalo in Bolivia and bocachico in Colombia. Three species occur in the Amazon: Prochilodus nigricans, P. rubrotaeniatus and a third undescribed Prochilodus sp.⁷⁰⁴

Two species have a very restricted distribution: Prochilodus rubrotaeniatus occurs only in the headwaters of the Negro, Branco and Trombetas rivers⁷⁰⁵ and the undescribed Prochilodus sp. has been reported in the headwaters of the Tapajós River. Therefore, most of the landings in the Amazon are probably of P. nigricans.

P. nigricans (max. 37 cm) is found in the Amazon River and its main tributaries, including the Tocantins River, at altitudes of up to 700 m and in the Brazilian, Peruvian, Colombian and Bolivian Amazon.⁷⁰⁶ It does not seem to occur above the middle reaches of black water tributaries. The species’ main habitats are the Amazon River, its white water tributaries and their associated floodplain. Newly hatched larvae are found in the Amazon River mainstem,⁷⁰⁷ but may drift in other white water tributaries as well. First feeding larvae and more developed stages are found in the adjacent floodplains,⁷⁰⁸ where they live among the roots of floating meadows, common in the floodplain during the spawning period.

Juveniles also spend most of their time associated with the herbaceous floodplain vegetation.⁷⁰⁹ Adults are found feeding in the floodplains of

⁷⁰⁰ Barthem, 1999

⁷⁰¹ Bittencourt, 1999

⁷⁰² Ruffino et al., 1998

⁷⁰³ Ribeiro et al., 1995

⁷⁰⁴ Castro, 1990

⁷⁰⁵ Castro, 1990; Ferreira, 1993

⁷⁰⁶ Loubens & Aquim, 1986

⁷⁰⁷ Nascimento, 1992

⁷⁰⁸ Bayley, 1983; Fernández, 1993

⁷⁰⁹ Fernández, 1993

the Amazon River and its tributaries, especially in the flooded forest or under the herbaceous vegetation,⁷¹⁰ and migrating in the Amazon River and white water tributaries.

This species seems to have at least two migratory patterns. In the Amazon Basin, excluding the Tocantins River, P. nigricans adults migrate between successive floodplain lakes during the receding water season (September).⁷¹¹ The distance they migrate during this period has not been measured. Later, at the beginning of the flooding season, this species leaves the floodplain lake systems to spawn in the mouths of their inlets.⁷¹² The larvae drift in the river up to 15 days,⁷¹³ eventually being carried to the floodplain. Juveniles probably recruit to migrating schools at one or two years of age. The same pattern has been reported for the Madeira River.⁷¹⁴

The migration in the Tocantins River seems to differ from the above pattern.⁷¹⁵ Before the construction of Tucuruí Reservoir, the fish left the floodplain during low water season and moved upstream. At the beginning of the flood season they spawned in an extended upriver region and then migrated downstream to the floodplain. The eggs and larvae were believed to drift passively towards the floodplains.

After the reservoir was constructed the movements remained similar in the Middle and Upper Tocantins rivers. At the beginning of the low water period the fish leave the floodplain and the reservoir and migrate upstream, and apparently schools of fish from the Lower Araguaia River also join this upstream migration. At the confluence of the Tocantins River and its tributary the Araguaia River, the fish seem to swap rivers. The fish of Tocantins River migrate upstream into the Lower Araguaia River and the inverse occurs as well.⁷¹⁶ When the water level starts to rise, schools of fish move to tributaries to spawn in the shallow and recently inundated areas (although spawning also takes place in the river). After spawning fish return to the reservoir or to their original floodplain lakes. Large numbers of young juveniles are found in the reservoir and floodplain lakes, so downriver larval drift must occur.

⁷¹⁰ Mérona, 1988; Mérona & Bittencourt, 1993

⁷¹¹ Fernandes, 1997

⁷¹² Schwassman, 1978; Araujo-Lima, 1984; Petry, 1989

⁷¹³ Araujo-Lima, 1994; Araujo-Lima & Oliveira, 1998

⁷¹⁴ Goulding, 1980

⁷¹⁵ Carvalho & Mérona, 1986

⁷¹⁶ Ribeiro et at, 1995

Landings – In Tefé, landings in 1992, 1993 and 1994 averaged 232 tons/y of curimatã.⁷¹⁷ During 1997 landings in three cities (Manacapuru, Itacoatiara and Parintins) were 434 tons of curimatã.⁷¹⁸ Data for Santarém in Pará State from 1992, 1993 and 1994 revealed landings of 391, 185 and 962 tons of curimatã,⁷¹⁹ with an average CPUE of 6.8 kg/fisher/day. Landings are very high in Manaus reaching over 5,000 tons/y in 1996.⁷²⁰

Potamorhina spp., Curimata spp. and related species

The fish marketed as branquinha is made up of many relatively small detritivore species (max. < 25 cm) within several genera. Fish from the genera Potamorhina and Curimata dominate landings, but Psectrogaster and Curimatella are also harvested occasionally. Vari⁷²¹ has recently reviewed the family and its taxonomy is now better organised.

Three species of Potamorhina (P. latior, P. altamazonica and P. pristigaster), six species of Curimata (C. ocellata, C. vittata, C. kneri, C. inornata, C. incompta and C. cisandina), two species of Psectrogaster (P. rutiloides and P. amazonica) and at least three species of Curimatella (C. dorsalis, C. meyeri and C. immaculata) are found in the Central Amazon and in the headwaters of nutrient-rich rivers.⁷²² C. cyprinoides was found only in the Tocantins and Araguaia rivers and C. aspera in the Upper Solimões River.⁷²³

The larvae of Potamorhina latior and P. altamazonica, P. rutiloides, P. amazonica drift in the mainstem of the Amazon River,⁷²⁴ but not much is known about the larvae of Curimata and Curimatella spp. Juveniles are found in the floating macrophytes of floodplain lakes, while adults inhabit the flooded forest and the mainstem of the Amazon River.

Landings – Branquinha landings seem to be increasing in Manaus; in Acre, where their landings are higher, there are no time-series statistics.

⁷¹⁷ Barthem, 1999

⁷¹⁸ Bittencourt, 1999

⁷¹⁹ Mota & Ruffino, 1997

⁷²⁰ Batista, 1998

⁷²¹ Vari, 1984, 1989a, 1989b, 1992

⁷²² Goulding, 1979, 1980; Vari, 1984, 1989a, 1989b, 1992; Silvano et al., 2000

⁷²³ Vari, 1989a

⁷²⁴ Nascimento, 1992; Araujo-Lima, 1991

Document(s) 8 de 11