RESUMO O presente trabalho consistiu em avaliar as concentrações de nutrientes e metais pesados nos sedimentos do fundo do lago Água Preta, localizado na Região Metropolitana de Belém, Estado do Pará. As concentrações de metais pesados foram obtidas por espectrometria de emissão por plasma acoplado a espectrometria de massas (ICP-MS). Os metais que apresentaram maior concentração foram o cromo (245 mg.Kg-1) e o níquel (97 mg.Kg-1), os quais estiveram acima do índice que determina o nível de efeito provável (Probable Effect Level - PEL). O trabalho evidenciou o reflexo das pressões antrópicas que o lago Água Preta vem sofrendo ao longo dos anos, mostrando que os sedimentos de fundo se encontram impactados por metais pesados, altas cargas de matéria orgânica e nutrientes.

ABSTRACT The present study evaluated the concentrations of nutrients and heavy metals in bottom sediments of Água Preta lake, located in the metropolitan region of Belém, Pará state, Brazil. Concentrations of heavy metals were obtained by emission spectrometry with inductively coupled plasma mass spectrometry (ICP-MS). Metals that showed high concentrations were chromium (245 mg.Kg-1) and nickel (97 mg.Kg-1), both above Propable Effect Level (PEL) index. The work revealed the reflection of the anthropogenic pressures that Água Preta lake has suffered over the years, showing that the bottom sediments are impacted by heavy metals, high loads of organic matter and nutrients.

ABSTRACT The objective of this study was to evaluate menthol and eugenol as anesthetics for early juveniles of curimba, Prochilodus lineatus. Juveniles of 4.0±0.5 g and a total length of 8.8±0.1 cm were exposed to the anesthetics menthol (20, 30, 40, 50, 60, 70, and 80 mg L−1) and eugenol (20, 30, 40, 50, 60, and 70 mg L−1) up to deep anesthesia. The anesthetic effects were evaluated measuring the induction time to deep anesthesia (characterized by loss of equilibrium, absence of swimming, reduction of opercular movements, and responses only to intense tactile stimuli), recovery time, time to appetite return, and mortality rate after 96 h of procedure. The concentrations between 60 to 80 mg of menthol L−1 provided the lowest time of induction. Increased concentrations led to a decrease in recuperation time. The concentrations between 50 to 70 mg of eugenol L−1 provided the lowest induction times; however, recovery time was not affected by eugenol concentrations. The return to appetite was observed 24 h after anesthesia, while the survival after 96 h was >90%. Concentrations of 60 and 50 mg L−1 of menthol and eugenol, respectively, are recommended for effective anesthesia with limited side effects.

A família Bathylagidae apresenta oito gêneros e 22 espécies, sendo que apenas cinco destas espécies ocorrem no Atlântico Sudoeste. No sul do Brasil já havia sido registrada a ocorrência de exemplares adultos de Melanolagus bericoides entre o Cabo de Santa Marta e Rio Grande (31° S e 49° W). Este trabalho registra a primeira ocorrência de larvas de Dolicholagus longirostris na costa norte brasileira, ampliando sua distribuição no Atlântico Sudoeste. Os dois exemplares encontrados foram coletados na foz do Rio Amazonas (02° 00' 19" N, 47° 03' 30" W, e 00º 49' 06" N, 46º 25' 09" W).

The family Bathylagidae contains eight genera and 22 species, of which only five occur in the Southwest Atlantic. Until recently, only adult specimens of the bathylaginin Melanolagus bericoides had been recorded off southern Brazil, between the Santa Marta Cape and Rio Grande (31° S and 49° W). The present work reports the first occurrence of Dolicholagus longirostris larvae on the northern Brazilian coast, expanding its distribution in the Southwest Atlantic. The two specimens found were collected near the mouth of the Amazon River (02° 00' 19" N, 47° 03' 30" W, and 00° 49' 06" N, 46° 25' 09" W).