A malhadeira é um apetrecho de pesca frequentemente utilizado na pesca regional. O presente estudo visa verificar características das malhadeiras utilizadas nos diversos subsistemas da Amazônia Central, seu uso e a aplicação de normas legais relacionadas. Os dados foram obtidos por meio de entrevistas com pescadores em Manaus entre 1994 e 2004 e em Manacapuru entre 2001 e 2004. Os resultados indicaram que o apetrecho responde em média a 14% da produção pesqueira de Manaus, com tendência a diminuição e a 24,5% de Manacapuru, com estabilidade interanual. As freqüências modais recentes do tamanho de malha estiveram entre 50-60 mm no desembarque em Manaus, mas em Manacapuru foram mais diversas, entre 20 mm e 90 mm. A moda do comprimento das redes foi de 100 m em ambos portos, mas se em Manaus correspondem a cerca de 90% das registradas, em Manacapuru não são nem 50% do total. Quanto à freqüência de ocorrência de uso da malhadeira nos subsistemas da Amazônia Central que desembarcaram em Manaus, destaca-se o rio Purus (47,8%), enquanto que para Manacapuru predominou explotação no Baixo Solimões (94,3%). A composição das capturas variou entre os anos analisados, destacando cinco principais pescados que compõem mais de 70% das capturas: tambaqui, aruanã, tucunaré, curimatá, pirapitinga. Com relação às restrições no tamanho de malha, a maioria dos apetrechos têm tamanho de malha passível de uso ilegal, similarmente aos comprimentos das mesmas. Concluiu-se que há grande diversidade de formas de uso do apetrecho, sendo necessário gerar normas legais mais efetivas e compatíveis com a realidade pesqueira, cultural e sócio-econômica da Amazônia.

The gillnet is frequently used in Amazon commercial and artisanal fishing. The present study aims to verify characteristics of the gill-nets of gillnets found in various Central Amazon subsystems, their use, and compliance with related legal norms. Daily Interviews were made from 1994 to 2004 in Manaus, and from 2001 to 2004 in Manacapuru. The results indicated that the gillnet was responsible for about 14% of the yield landed in Manaus, with a tendency to diminish, but a stable 24,5% in Manacapuru. Modal mesh sizes were 50-60mm in Manaus, but ranged from 20 to 90mm in Manacapuru, and the modal length was 100 m for both. In Manaus this size accounted for about 90% of all gillnets recorded, but in Manacapuru it was less than 50%. The Manaus fleet preferred to exploit the region of Purus (47,8%), while the Manacapuru fleet preferred the Low Solimões (94,3%). The composition of gillnet catches varied during the interviewed years, but 70% of the total was usually made up of tambaqui, aruanã, tucunaré, curimatá, and pirapitinga. Most mesh sizes and lengths were illegal. We concluded that the legal norms for gillnet use should be adapted to fishery characteristics, but also to the socioeconomic and cultural reality of the Amazon.

The catfish Trachelyopterus striatulus Steindachner, 1877 is a very abundant fish species in reservoirs in Southeast Brazil, and its relative abundance seems to be increasing in several lentic environments. Despite of being a very common species, few information is available on its distribution and other aspects of ecology. The Lajes reservoir (22º42'-22º50'S e 43º53'-44º05'W) is the largest manmade lake for hydropower purposes in Rio de Janeiro State, where this species rank among the top abundant fishes, both in number and in biomass. Its relative abundance were compared in three zones of the reservoir (upper, central and lower), based on a standardized program, during three annual periods (monthly sampling in 1994 and bi-monthly sampling in 1996 and 1997), with a total of three hundred twenty samples, using gill nets. Environmental variables of water temperature, pH and transparency were taken in each sampling occasion, and information on rainfall and level of the water were recorded. Trachelyopterus striatulus showed an increasing abundance during the study period, rising from fifty rank in 1994 to the most abundant fish in 1997, coinciding with decreasing water level, and suggesting that this species take advantage of the harsh conditions in the reservoir to increase population. Highest number and weight were recorded in the upper zone, which presented the lowest transparency. Seasonally no significance (p > 0,05) difference in abundance was found over the whole period.

The white croaker Micropogonias fumieri (Desmarest, 1823) is one of the most abundant fish species in the Sepetiba Bay, being heavily exploited in fisheries. Two hundred eleven fishes, captured from October 1998 to September 1999, in monthly samplings with otter trawling, were studied. The aim here is to characterize morphometrics of populations that use de Bay in order to compare with other areas. Measurements included standard length (SL), head length (HL), Pre-dorsal distance (PDD), pectoral distance (PD), ventral distance (VD) and anal distance (AD), pectoral length (PL) and eye diarneter (ED). The values of HL, PDD, PD, VD, AD, were related to SL, while ED was related to HL. Scatterplot from logaritrnized data, by sex, were analyzed in order to assess alometry. Males outnumber females with differences being highly significant (p < 0.01), mainly in size c1ass 100 and 150 mm SL. The studied population varying from 62 to 205 mm. Head length varied from 28.7 to 38.6% SL; PDD 32.5 to 42.9%; PD 276 to 41.1 %; VD 26.6 to 44.8%; AD 58.1 to 76.8%; and PL 10.8 to 29.8%. Eye diameter varied from 16.7 to 26.1 % HL. Positive alometry (k > I) were shown for PL in both sexes, and for AD in female, indicating that these measurements increase proportionately more than the standard length; isometric growth (k = 1) were shown for HL, PDD, PD, VD in both sexes, for AD in males; negative alometry (k < 1) was shown only for ED in relation to head length (HL), in both males and females. The white croaker populations in lhe Sepetiba Bay seems to be similar in their morphometrics aspects to the populations of coastal zone at Southeast Brazil, which differ from South coastal zone populations.

The length-weight relationship of populations of white croaker Micropogonias furnieri (Desmarest, 1823) in the Sepetiba Bay (22º54'-23º04'S; 43º34'-44º10'W), were assessed. It aims to contribute to the knowledge of the biometrics and to estimate the biomass of this very abundant fishery resource in the Bay. Fishes sampled, in both trawling beach seine, sampling programme, from October 1998 to May 1999 were analyzed. The equation found was W = 0.00000942 L2.99 fom the natural logaritmized transformation of the raw data, through ordinary least square equation = In W = -11.57 + 2.996 In L (r=0.99). The condition factor was relatively high compared with coastal population from Southeast Brazil, probably due to in this study both males and females from juvenile and adult were considered, while in coastal areas, only adult female were analyzed. The alometry coefficient (θ), on the other hand, is very similar to the coastal Southeast Brazil population, but differed from Northeast and South Brazil populations.