The demand for alternative food sources is currently in evidence in the world and, therefore, the culture of animal species considered not conventional makes this theme relevant and appropriate. In the present study, the species Pomacea lineata and Pomacea bridgesii, each with three stowage densities (0.5 [T1], 1 [T2], and 1.5 [T3] animal/L), were tested. They were analyzed regarding growth rate, weight gain, final biomass, feed conversion and percentage of survival. There was not any statistically significant difference between the different densities for both species. The final average weight in the three waterworks did not differ significantly in P. bridgesii. In P. lineata, T1 (22.3 ± 1.80g) was significantly higher than T2 and T3. On the other hand, the absolute gain of weight in P. lineata and P. bridgesii was significantly higher in T1 (21.9 ± 1.80g and 37.2 ± 6.34g) than in T2 and T3 respectively. In contrast, the gain of biomass of P. lineata and P. bridgesii was significantly higher in T3 (276.3 ± 33.16g and 431.4 ± 37.20g) than in T1 and T2, respectively. Based on the results obtained, all species studied presented potential for aquaculture, mainly P. bridgesii, distinguished for showing a better development even in waterworks with higher densities.

Este trabalho avaliou a eficiência de quatro tipos de coletores de sementes no recrutamento de ostras Crassostrea sp., em cinco pontos do estuário do Rio Benevente, município de Anchieta, e em duas ilhas no município de Piúma, estado do Espírito Santo. Foram utilizados quatro tipos de coletores: 1-conchas de ostras, 2- garrafas PET, 3-tiras de pneu e 4- telhas, todos suspensos por cordas e amarrados em rizóforos de Rhizophora mangle ou em "long-lines" de mexilhões. Bimensalmente, as sementes recrutadas foram contadas e medidas quanto à altura, determinando-se os parâmetros físico-químicos-tróficos da água: salinidade, temperatura, oxigênio dissolvido, matéria orgânica particulada e clorofila-a, que foram correlacionados com o número de sementes nos coletores (através de correlações de Spearman). O recrutamento de sementes foi significativamente maior nos coletores de conchas de ostras, telhas e pneus, principalmente nos pontos de salinidade mais alta (Praia do Coqueiro em Anchieta e Ilhas do Meio e do Cabrito em Piúma) (Kruskal-Wallis: H= 10,01; 3 g.l.; P < 0,05). A fixação de sementes ocorreu durante todo o ano, sendo mais alta de novembro a fevereiro; porém, devido ao alto número de coletores perdidos por roubo ou tempestades, esta diferença não foi significativa (Kruskal-Wallis: H=1,42; 7 g.l.; P >0,05). O número de sementes de ostras foi positivamente correlacionado com a salinidade (ρs= 0,331; P < 0,05) e temperatura da água (ρs= 0,48; P < 0,05), indicando que os locais de salinidades mais altas e os meses de verão são os melhores para se coletar sementes de ostras.

This paper evaluated the effectiveness of four types of oyster spat collectors, made with recycled materials, in the recruitment of the mangrove oyster Crassostrea spp. at five sites in the Benevente river estuary, Anchieta District and on two islands in Piúma District, both in Espírito Santo State. The collectors were made of: 1- oyster shells, 2- PET bottles, 3- car tires and 4- tiles, all of them suspended by ropes and tied to roots of Rhizophora mangle or mussel long-lines. The number of spat recruited on each collector and their shell lengths were registered bimonthly, as well as the physico-chemical-trophic parameters of the water: salinity, temperature, dissolved oxygen, particulate organic matter and chlorophyll a, which were correlated (by Spearman's correlation) with the number of spat recruited. Spat settlement was significantly higher on oyster shell, tile and tire collectors, mainly at points with higher salinities, such as Praia do Coqueiro in Anchieta and on Meio and Cabrito Islands in Piúma (Kruskal-Wallis: H= 10.01; 3 d.f.; p < 0.05). Oyster spat recruitment occurred throughout the year, being higher from November to February, but because of losses due to storms or theft, the difference was not statistically significant (Kruskal-Wallis: H=1.42; 7 d.f.; p > 0.05). The number of oyster spat was positively correlated with the salinity (ρs= 0.331; p < 0.05) and water temperature (ρs= 0.48; p < 0.05), revealing that areas with higher salinities and summer months were better for spat collection.

Sementes de Perna perna foram colocadas em cordas suspensas em long-line na Praia do Coqueiro, Anchieta, ES, objetivando-se determinar a estrutura da comunidade de incrustantes e seu efeito sobre o desenvolvimento dos mexilhões. Metade das cordas teve os incrustantes removidos mensalmente, na outra metade eles foram deixados até o final do experimento. Mensalmente, 30 mexilhões de cada grupo foram retirados e medidos e a biomassa aferida. Os incrustantes foram identificados, quantificados e a biomassa de cada taxon determinada. Após 10 meses de cultivo, os mexilhões sem incrustantes eram significativamente maiores e mais pesados (ANOVA; P < 0,05; Bonferroni: sem incrustantes > com incrustantes), demonstrando que os incrustantes interferiram negativamente no desenvolvimento dos mexilhões. Os incrustantes mais abundantes em termos de biomassa foram as algas Polysiphonia subtilissima (29%) e Ulva rigida (10,3%), seguidas pelos briozoários Bugula neritina (13,6%) e sementes de Perna perna (10,6%). Foram registrados 97 taxa e 42.646 indivíduos, sendo Crustacea o grupo mais abundante, principalmente o anfípodo Cheiriphotis megacheles (12.980 ind.). A abundância de indivíduos foi positivamente correlacionada com a biomassa de algas, revelando a influência das algas na fauna vágil, provendo abrigo e alimentação. Os benefícios da remoção dos incrustantes são discutidos, uma vez que a maioria dos incrustantes são importantes como itens alimentares para os peixes; além disso, os custos desta remoção somados à perda de sementes de mexilhões, tornam a remoção desta comunidade de incrustantes questionável.

Perna perna mussel spat were suspended from ropes on a long-line cultivation, at Coqueiro´s Beach, Anchieta, South-eastern Brazil, in order to quantify the fouling community structure and its effects on growth and biomass of mussels. Half of the ropes had the fouling removed monthly, half had the foulingleft until the end of the experiment. Monthly samples of thirty mussels from each group were measured and their biomass determined. The fouling organisms were identified, quantified and their biomass evaluated on a monthly basis. After ten months, mussels on the cleaned treatment were significantly larger and heavier (ANOVA; P < 0.05; Bonferroni: unfouled > fouled), showing that fouling reduced mussel development. The most abundant epibiont organisms in terms of biomass were the algae Polysiphonia subtilissima (29%) and Ulva rigida (10.3%), followed by the bryozoans Bugula neritina (13.6%) and Perna perna spat (10.6%). Over 97 taxa and 42,646 individuals were identified, crustaceans being the most abundant group, predominantly one amphipod Cheiriphotis megacheles (12,980 ind.). Species abundance was positively correlated with algal biomass, revealing the influence of algae on vagile fauna, which provide both food and shelter. The benefits of fouling removal are discussed because the majority of species are important feeding items to fishes and yet, the costs of its fouling control added to the associated mussel spat loss make this fouling removal of questionable value.