The present study compared losses of weight and length in specimens of Atherinella brasiliensis (Quoy & Gaimard, 1825) after fixation in formalin 10% during ten days, and posterior preservation in ethanol 70% for 45 days, in two solvents: freshwater and marine water. Additionally, correction factors were proposed to calculate the correction for weight and length from preserved specimens. The specimens were weighted and measured after collection (fresh), and with 10, 20, 27, 34, 41 and 55 days of fixation plus preservation. The largest losses in weight occurred during the first 20 days (10.35 ± 0.31% - freshwater; 11.29 ± 0.44% - marine water), continuing with lesser intensity up to the 27th day in freshwater dilution, and up to the 34th day in marine water dilution. Weight losses stabilized by the 34th day for both freshwater (11.77 ± 0.33%) and marine water (13.62 ± 0.41%). The largest losses in the total length for the two methods were also observed in the first 20 days (7.42 ± 0.27% - freshwater; 9.76 ± 0.26 - marine water), stabilizing after the 27th day in freshwater (8.60 ± 0.26%) and 20th day in marine water (9.76 ± 0.26%). The losses of weight and total length were significantly dependent on fish size, with smaller individuals suffering the most significant losses. Complete regression equations were proposed for the retro-calculation of fresh weight and total length from the preserved specimens for freshwater (Wfresh = 1.0536W P + 0.0416; TLfresh = 0.9588TL P + 5.8437) and marine water (Wfresh = 1.0868W P + 0.0451; TLfresh = 0.8621TL P + 10.425).

A distribuição de manjubas (Clupeiformes, Engraulidae) foi descrita na Baía de Sepetiba, uma área costeira do Sudeste do Brasil, para determinar eventuais mecanismos de seleção de habitat. Dois programas de amostragem foram realizados; um usando arrasto de praia (1998/2000) para captura de juvenis, e outro, usando arrasto de fundo (1999/2000) para captura de adultos. Seis espécies representadas por quatro gêneros foram capturadas: Anchoa tricolor, Anchoa januaria, Anchoa lyolepis, Cetengraulis edentulus, Engraulis anchoita e Lycengraulis grossidens. Anchoa tricolor e A. januaria foram as espécies mais abundantes, com a primeira ocorrendo principalmente na zona externa da baía, enquanto a segunda com maior abundância na zona interna. Adultos A. tricolor são alvo de intensas pescarias comercial na baía durante a Primavera-Verão, enquanto E. anchoita, uma abundante espécie na plataforma continental, foi ocasionalmente capturada em grande numero durante o Outono. A seleção de hábitat, através do uso de diferentes áreas da baía, foi desenvolvida pelas duas espécies mais abundantes, um provável mecanismo para permitir a coexistência.

Distribution of anchovies (Clupeiformes, Engraulidae) was described in the Sepetiba Bay, a coastal area of Southeastern Brazil, to assess eventual mechanisms of habitat selection. Two fish sampling programmes were accomplished; one using beach seine (1998/2000) to catch juveniles in sandy beaches, and the other, using seines (1999/2000) to catch adults in deeper bay areas. Six species representing 4 genera were recorded: Anchoa tricolor, Anchoa januaria, Anchoa lyolepis, Cetengraulis edentulus, Engraulis anchoita and Lycengraulis grossidens. Anchoa tricolor and A. januaria were the most abundant species, with the former peaking in the outer bay, while the latter peaking in the inner bay. Adults A. tricolor are target of heavy commercial fisheries in the bay during Spring-Summer, while E. anchoita, an abundant species in the continental shelf, was occasionally caught in large numbers during the Autumn. The habitat selection, by using two different bay areas, was developed by the two most abundant species, a probable mechanism to enable their coexistence.

Efeito do tempo de conservação dos espécimes sobre a qualidade dos microincrementos em otólitos sagittae de Anchoa tricolor (Agassiz) (Clupeiformes, Engraulidae). O número de microincrementos em otólitos sagittae de espécimes de pós-larvas de Anchoa tricolor (Agassiz, 1829) fixadas em formol 10% foram comparados em diferentes períodos de conservação (quatro dias versus quatro anos). Diferenças significativas foram encontradas no número de microincrementos para pós-larvas variando de 20-26 mm de comprimento total (CT), com médias de 18,6 microincrementos (± 0.75 erro padrão) para peixes preservados por quatro anos, e 35,3 microincrementos (± 1.28 erro padrão) para peixes preservados por quatro dias. Portanto, o número de microincrementos em otólitos de pós-larvas preservados por longos períodos pode não ser adequado para inferências de taxas de idade ou crescimento. Adicionalmente, não foram detectados ou extraídos otólitos em pós-larvas menores do que 20 mm CT devido a maior composição de matéria orgânica durante esta fase do ciclo de vida.

We compared the number of microstructure of Anchoa tricolor (Agassiz, 1829) post-larvae sagittae otoliths in specimens fixed in formalin 10% in different periods of conservation (four days versus four years). Significant differences were found in the number of microstructure for post-larvae ranging from 20-26 mm total length (TL), with averages of 18.6 microstructures (± 0.75 standard error) for fishes preserved for four years, and 35.3 microstructures (± 1.28 standard error) for fishes preserved for four days. Therefore, the number of post-larvae otoliths microstructure preserved for long periods can not be suitable to infer age or growth rates. Additionally, we failed in detecting and extracting otoliths in post-larvae smaller than 20 mm TL preserved due to its comparatively higher organic matter composition, mainly during the early life cycle.