Lemon sharks Negaprion brevirostris were sampled in the Atol das Rocas, a nursery area, on nine occasions from March 1999 to October 2003, during which 157 individuals were tagged and 35 were recaptured. The male : female sex ratio of captured individuals was 1 : 1Á12. Mean AE S.D. growth rates were 24Á7 AE 3Á4 cm year À1 in total length (L T ), 20Á7 AE 3Á2 cm year À1 in fork length, and 19Á5 AE 2Á7 cm year À1 in precaudal length. There was no significant difference in growth rates between males and females. Mean AE S.D. increase in mass was 2565 AE 762 g year À1 . The von Bertalanffy growth parameters estimated by the Fabens method based on L T were: k ¼ 0Á077, L 1 ¼ 399Á9 cm and t 0 ¼ À2Á16. Despite the large variation of environmental conditions, particularly of tidal range and currents, and the lack of protective mangrove cover in the nursery area at Atol das Rocas, juvenile lemon sharks grew relatively faster than at other nurseries. Such rapid growth could be a response to abundant food availability or high risk of predation by adults that enter the nursery area.

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The consumption of raw fish has increased considerably in the West, since it is said to be potentially healthier than processed fish (for containing omega 3 and 6, essential amino acids and vitamins). However this potential benefit, as well as the taste, value and even the risk of extinction are not the same for all species of fish, constituting grounds for fraud. Using the principles of the DNA barcode we revealed mislabelling of fish in Japanese restaurants and fishmarkets in Florianópolis, a popular tourist capital in Brazil. We sequenced the COI gene of 65 samples from fisheries and 80 from restaurants and diagnosed 30% of mislabeled samples in fisheries and 26% in restaurants. We discussed that frauds may have occurred for different reasons: to circumvent surveillance on threatened species; to sell fish with sizes smaller than allowed or abundant species as being a much rarer species (law of supply); to induce product consumption using species with better taste. It should be noted that some substitutions are derived from incorrect identification and are not a fraud per se; they are due to confusion of popular names or misunderstanding by the sellers. Therefore, we suggest the implementation of a systematic regulatory program conducted by governmental agencies to reduce mislabelling in order to avoid further damage to the community (in health and financial issues) and fish stocks.

Nile tilapia fish were individually reared under similar light levels for 8 weeks under five colored light spectra (maximum wavelength absorbance): white (full light spectrum), blue (∼452 nm), green (∼516 nm), yellow (∼520 nm) or red (∼628 nm). The effects of light on feeding, latency to begin feeding, growth and feed conversion were measured during the last 4 weeks of the study (i.e., after acclimation). We found that red light stimulates feeding, as in humans, most likely by affecting central control centers, but the extra feeding is not converted into growth.

Investment in SARS-CoV-2 sequencing in Africa over the past year has led to a major increase in the number of sequences generated, now exceeding 100,000 genomes, used to track the pandemic on the continent. Our results show an increase in the number of African countries able to sequence domestically, and highlight that local sequencing enables faster turnaround time and more regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and shed light on the distinct dispersal dynamics of Variants of Concern, particularly Alpha, Beta, Delta, and Omicron, on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve, while the continent faces many emerging and re-emerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century.

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