RESUMO

Wrack removal has been adopted indiscriminately, with no previous assessment of the ecological implications for sandy beach ecosystem. This study evaluated, through an M-BACI design, the effect of wrack removal on supralittoral arthropods on Atlantic sandy beaches receiving different types of wrack: mangrove propagules (Brazil), seagrasses and macroalgae (Spain). Impacted plots were contrasted with controls in 8 successive periods before and after experimental wrack removal. After the disturbance, drastic decreases in the densities of the amphipod Platorchestia monodi, coleopterans Cleridae, Nitidulidae and Phaleria testacea (Brazilian beaches) and amphipod Talitrus saltator (Spanish beaches) were detected in the impacted plots. The recovery patterns of arthropods might be related to wrack features (amount, composition, and degradation) combined with density and species-specific strategies (e.g. mobility, feeding preferences) in each Atlantic region. The temporary suppression of wrack and its associated fauna can have potential effects on the wrack-derived process and food-web structure on sandy beaches.

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Abstract Lytechinus variegatus (Lamarck) is a common echinoid found on the Atlantic coast of America from North Carolina to southern Brazil and their populations inhabit sub littoral shallow-water environments. This research examined some aspects of reproduction in the southern limit of distribution of the species. A total of 86 adult individuals of L. variegatus (50.8 to 77.0 mm test diameter) were manually collected from September 2000 to September 2001 along the unconsolidated bottoms at the eurihaline sector of Paranaguá Bay (48° 19' W - 25° 35' S) for histological characterization of gametogenesis, sex ratio and gonadal index (GI) evaluation. This population showed a synchronicity in maturation and spawning events (autumn and winter respectively), with a 1:1 sex ratio (χ2 = 2.57, df = 7, p < 0.05). The GI increase was associated with storage of nutritional resources periods (resting stages and proliferation) that occurred between late winter and spring. Biometric analyzes indicated a greater investment in size and/or quantity of gametes between late spring and summer, when it was possible to observe mature sperm occupying on average 63.9 % of the follicular lumen and oocytes reaching values of 70.0 to 75.0 μm. Mature oocyte mean size is the highest diameter of those developed by other regular echinoids in the same latitude. However, the average diameter of mature oocytes of L. variegatus in the southern limit of its distribution was lower than the values recorded for the northern hemisphere. Rev. Biol. Trop. 63 (Suppl. 2): 243-250. Epub 2015 June 01.

Resumen Lytechinus variegatus (Lamarck) es un equinoide común en la costa atlántica de América, desde Carolina del Norte, Estados Unidos, al sur del Brasil y sus poblaciones habitan ambientes sublitorales de aguas someras. Este trabajo examina algunos aspectos de la reproducción en el límite sur de distribución de la especie. Un total de 86 individuos adultos (50.8 a 77.0 mm de diámetro de testa) fueron colectados manualmente de septiembre de 2000 a setiembre de 2001, en fondos blandos del sector eurihalino de la bahía de Paranaguá (48° 19' W - 25° 35' S), para caracterización histológica, proporción de sexos y evaluación del índice gonadal (IG). La población exhibió sincronización en los eventos de maduración y liberación de gametos (otoño e invierno, respectivamente), con una proporción de sexos de 1:1 (χ2 = 2.57, df = 7, p < 0.05). El aumento del IG estuvo asociado a periodos de acumulación de recursos nutricionales (estadios de reposo y proliferación) que ocurrieron entre el final del invierno y el verano. Análisis biométricos indican una gran inversión en tamaño y cantidad de gametos entre final de primavera y verano, cuando es posible observar gametos maduros ocupando, en promedio 63.9 % del lumen folicular, y ovocitos alcanzando diámetros de 70 a 75 μm. El tamaño medio de los ovocitos maduros es el mayor entre los equinodermos regulares de la misma latitud. Sin embargo, el tamaño medio del diámetro de los ovocitos de L. variegatus en su límite sur de distribución es menor que los valores registrados para el hemisferio norte. Llegamos a la conclusión de que a través de su distribuición geográfica extensa, los factores ambientales locales modulan el ritmo y la magnitud de la reproducción en poblaciones de este equinodermo.

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At the coast of Paraná State, a small-scale trawl fishery directed to the sea bob shrimp (Xiphopenaeus kroyeri) produces an abundant by-catch. The present study determined the temporal and spatial variation of Decapoda shrimp composition in the by-catch throughout monthly trawls carried out between August 2004 and July 2005 along five transects and covering 6 m, 9 m, 12 m and 15 m deep at each transect. During the studied period, seven species of peneid shrimps, one of sergestid and a variable number of carid shrimp were catch, in a total of 3,464 individuals. This represents less than 2% of the total shrimp catch, including the target species. The white shrimp, Litopenaeus schmitti, was the most abundant species, followed by Rimapenaeus constrictus, Sicyonia dorsalis, Pleoticus muelleri and the carid Exhippolysmata oplophoroides. The pink-shrimp species Farfantepenaeus paulensis and F. brasiliensis together with Artemesia longinaris were the less abundant ones.

No litoral do Paraná, o camarão-sete-barbas (Xiphopenaeus kroyeri) é explorado por embarcações artesanais providas de redes de arrasto com portas, que capturam fauna acompanhante, ou by-catch. Este estudo teve como objetivo principal determinar a variação espaço-temporal das espécies de camarão que compõem a fauna acompanhante de X. kroyeri na plataforma rasa do litoral paranaense, entre agosto de 2004 e julho de 2005, através de arrastos mensais realizados em cinco transectos nas profundidades de 6 m, 9 m, 12 m e 15 metros. Os resultados revelam a presença de sete espécies de camarões peneídeos e uma de sergestídeo, além de alguns exemplares de camarões carídeos. Foi registrado um total de 3.464 indivíduos, representando menos de 2% do total de camarões capturados. A espécie mais representativa foi Litopenaeus schmitti, seguida por Rimapenaeus constrictus, Sicyonia dorsalis, Pleoticus muelleri e pelo carídeo Exhippolysmata oplophoroides. As espécies de camarão-rosa Farfantepenaeus paulensis e F. brasiliensis, juntamente com Artemesia longinaris, foram as menos abundantes.

RESUMO

At the coast of Paraná State, a small-scale trawl fishery directed to the sea bob shrimp (Xiphopenaeus kroyeri) produces an abundant by-catch. The present study determined the temporal and spatial variation of Decapoda shrimp composition in the by-catch throughout monthly trawls carried out between August 2004 and July 2005 along five transects and covering 6 m, 9 m, 12 m and 15 m deep at each transect. During the studied period, seven species of peneid shrimps, one of sergestid and a variable number of carid shrimp were catch, in a total of 3,464 individuals. This represents less than 2% of the total shrimp catch, including the target species. The white shrimp, Litopenaeus schmitti, was the most abundant species, followed by Rimapenaeus constrictus, Sicyonia dorsalis, Pleoticus muelleri and the carid Exhippolysmata oplophoroides. The pink-shrimp species Farfantepenaeus paulensis and F. brasiliensis together with Artemesia longinaris were the less abundant ones.

No litoral do Paraná, o camarão-sete-barbas (Xiphopenaeus kroyeri) é explorado por embarcações artesanais providas de redes de arrasto com portas, que capturam fauna acompanhante, ou by-catch. Este estudo teve como objetivo principal determinar a variação espaço-temporal das espécies de camarão que compõem a fauna acompanhante de X. kroyeri na plataforma rasa do litoral paranaense, entre agosto de 2004 e julho de 2005, através de arrastos mensais realizados em cinco transectos nas profundidades de 6 m, 9 m, 12 m e 15 metros. Os resultados revelam a presença de sete espécies de camarões peneídeos e uma de sergestídeo, além de alguns exemplares de camarões carídeos. Foi registrado um total de 3.464 indivíduos, representando menos de 2% do total de camarões capturados. A espécie mais representativa foi Litopenaeus schmitti, seguida por Rimapenaeus constrictus, Sicyonia dorsalis, Pleoticus muelleri e pelo carídeo Exhippolysmata oplophoroides. As espécies de camarão-rosa Farfantepenaeus paulensis e F. brasiliensis, juntamente com Artemesia longinaris, foram as menos abundantes.