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The Brazilian basslet (Gramma brasiliensis) is an ornamental fish species of significance to the fish market, and the development of a breeding protocol is of interest to the aquarium trade. There is little information regarding the behaviour of G. brasiliensis in captivity; thus, the aims of this study were to: (1) investigate pair and harem formation in different-sized aquaria (70 and 110 L) and tanks (150 and 310 L); (2) investigate the choice of different macroalgae species and synthetic materials by the fish for nest building in captivity; and (3) describe the courtship behaviour of captive fish and compare it with available literature for G. brasiliensis and Gramma loreto in natural environments. Based on the results, we suggest that G. brasiliensis should be kept in pairs because of their aggressive behaviour. Macroalgae of the genus Chaetomorpha and all synthetic materials were used by the fish to build nests. The courtship behaviour of G. brasiliensis in captivity is described for the first time and is similar to that reported for G. loreto in a natural habitat, namely ‘U-turn with body quivering’.

The reef fish community is one of the most explored fish stock by local and medium scale fishing activities as well as by the international ornamental fish trade. Despite these intense commercial activities, several reef species are poorly known. The reef fish community limited knowledge makes difficult the commercial regulation and also the adoption of conservation policies and general law enforcement. The present study deals with the molecular identification of a reef fish community from the Baia de Todos os Santos, Bahia, Brazil in order to construct a reference database for molecular identification of these species. We evaluated the molecular identification of 51 species included in 28 distinct families. The specimens were caught using freediving techniques and tissue samples were obtained from the epaxial musculature. The DNA barcoding methodology was used for the amplification of a 650bp fragment from the mitochondrial COI gene. Among the 51 obtained COI sequences, 16 of them represent new record for the species in the Brazilian coastal region including two species ( Gramma brasiliensis and Scarus trispinosus ) without any sequencing data available until now.

In the tropical Atlantic, the ichthyofauna between the coast of Brazil and the Caribbean regions, divided by the Amazon barrier, is very similar presenting several geminate species, including Gramma brasiliensis, endemic in Brazil, and its Caribbean counterpart Gramma loreto. Morphological and molecular studies have helped establish evolutionary patterns that sister-species of these two marine habitats are subjected to. However, their chromosomal characteristics are only beginning to be better characterized. Accordingly, a comparative cytogenetic analysis was carried out in G. brasiliensis and G. loreto, seeking evidence of cytotaxonomic markers implicated in the karyotypic diversification of these species and likely associated with speciation events. Heterochromatic regions and their affinity to fluorochromes GC- or AT-specific were identified, as well as the distribution of ribosomal DNA sites in chromosomes, either by silver nitrate impregnation (Ag-NORs) or dual-color FISH mapping with 18S and 5S rDNA probes. While displaying the same diploid number, 2n = 48 chromosomes, considered basal for Perciformes, the two species differed in karyotype structure, showing karyotypic formulas and species-specific heterochromatin pattern. The cytological characters found support the differentiating status of these species, possibly achieved under the conditions of allopatry due to the Amazon/Orinoco barrier, showing chromosomal peculiarities in Grammatidae species when compared to other groups of Perciformes.

Nesting is a common behaviour associated with reproduction in several taxa. Nevertheless, this important parental care behaviour is rarely reported for reef-associated fish. The present study provides the first description of bird-like complex nesting behaviour of the endangered basslet (Gramma brasiliensis). Males were observed building nests using macroalgae thalli around holes and depressions, in coralline substrate. Algae were used to camouflage the nest entrance and to form a cushioned bed for egg laying. Nesting is a critical aspect of the reproductive strategy of G. brasiliensis, so, this behaviour is a key factor for the management measures implications on the conservation of the species.

Many aspects of sex change in reef fishes have been studied, including behavior and social organization. However, gonad histology remains the most robust way to identify sexual patterns in fishes. Some uncommon tissues remain poorly described, such as the accessory gonadal structures found in species from the Gobiidae family, which are rare in other bony fishes. This is the first report of the testicular gland in Gramma brasiliensis and for the Grammatidae family. Between April 2011 and February 2012 eighty specimens were collected during four dive campaigns on the Taipus de Fora reef (13°56’20”S 38°55’32”W), Bahia, Northeast Brazil, and their sex was determined. Thirteen per cent of the active-females and 90% of the active-males had testicular gland tissue in their ovotestis. This discovery led to additional research into the characteristics of the gland tissue and its relationship with gonadal maturation. Three patterns of testicular gland development were found in Brazilian basslet ovotestis. Both ova and sperm-producing gonad contained testicular gland tissue, and the appearance of this tissue seems to be the first modification of ovotestis tissue marking the beginning of the protogynous sex-change process in G. brasiliensis. Resumo Diversos aspectos da troca de sexo em peixes recifais vem sendo estudados, incluindo comportamentos e organização social. Entretanto, a histologia das gônadas continua sendo a maneira mais robusta para se identificar padrões sexuais em peixes. Alguns tecidos incomuns, tais como as estruturas anexas a gônada encontradas em espécies da família Gobiidae e raras em outras espécies são pouco estudados. Este trabalho é a primeira descrição da glândula testicular em Gramma brasiliensis e para a família Grammatidae. Entre abril de 2011 e fevereiro de 2012, oitenta espécimes foram coletados durante quatro amostragens no recife de Taipus de Fora (13°56’20”S 38°55’32”W), Bahia, Brasil, e tiveram seus sexos determinados. Treze por cento das fêmeas ativas e noventa por cento dos machos ativos apresentaram tecido da glândula testicular em suas gônadas. Esta descoberta levou ao estudo da características dessa estrutura e sua relação com a maturação gonadal. Foram identificados três padrões de desenvolvimento da glândula testicular nas gônadas do Gramma brasiliensis. Tanto as gônadas produtoras de espermatozoides quanto as de oócitos apresentaram tecido da glândula testicular, e o surgimento desse tecido parece ser a primeira modificação gonadal do início da troca de sexo protogínica em G. brasiliensis.