Caracterização do nicho alimentar do polvo octopus insularis (cephalopoda: octopodidae): da população ao indivíduo

Octopus insularis, target species in this study, is the dominant benthic octopus of the North and Northeast Brazil. Studies on behavior and ecology of the species have been conducted primarily on oceanic islands, with little information on the continental populations. In this study, two regions of the coast of RN, Rio do Fogo and Pirangi, were chosen for the characterization of the niche by O. insularis populations. The dietary niche, habitat and distribution of O. insularis of oceanic islands and the mainland, were compared. In addition, individual characteristics of feeding behavior in a population at Atol das Rocas was studied, taking into account the size of individuals, the proximity of the dens and characteristics of their "personality". The diet of the Rio do Fogo population was composed mainly of bivalve molluscs (82%), unlike Pirangi population that has a diet consisting mainly of crustaceans Decapoda (68%), similar to that described for the populations of the islands. Consequently, the feeding niches of the island populations were more similar, with greater overlap, but the niche breadth of the continent was larger. The habitats of occurrence on the coast includes reefs, rocks, gravel and an environment called Restinga, a plateau composed of biogenic gravel, sand, sponges and algae, showed a high density of animals. Similarly to that found in the islands, O. insularis in the continent, had a clumped distribution, and a bathymetric segregation between small and large individuals. The differences in diet composition among populations were explained by differences in habitat and coverage of the substrate, which may be directly influencing the diversity and prey availability in these environments. The individual analyzes of the population at Atol das Rocas, showed no relationship between the degree of individual specialization and the different personalities, or the distance between dens. The results suggest that the foraging strategy with greater availability of prey in the environment has an influence on diet octopuses over preferences or personalities

Estrutura populacional e aspectos reprodutivos do Octopus insularis Cephalopodas: Octopodidae: implicações para o manejo da pesca de polvo no município de Rio de Fogo-RN

In northeastern Brazil, Octopus insularis is the most commercially important cephalopod species and its capture has been performed for several years by the lobster fishermen in the region. In order to obtain information about the reproductive biology, 1108 specimens were collected between November 2009 and September 2011 in the landings and fish markets of Rio do Fogo (RN). For each specimen the mantle length (CM) and total fresh weight (PT) were recorded. Gonads of 264 males and 295 females were examined macroscopically and histologically to assess sexual maturation and determine reproductive indices. Four reproductive stages were determined for males (immature, maturing, mature and post-mature) and females (immature, early maturing, late maturing and mature). The average of eggs recorded in the female s gonads was 93.820 and 39 was the average of spermatophores found in male Needham s complex. Spermathecae with sperm were found in females with 69 mm CM (immature). Males and females become sexually mature at 64.41 and 98.50 mm of CM, respectively. The weight at sexual maturity was 270 g for males and 630 g for females. The values of the size and weight at sexual maturity found in this study show that males mature at smaller sizes than females. For both sexes the maturation peaks occurred in February and November 2010 and also in September 2011. The periods of maximum reproductive activity lasted about 3 months and it seems to occur every 7 10 months. Only one spent female (stage V) was found and the number of mature females was low. Presumably, mature females migrate to deep waters with complex habitat to protect the offspring, indicating that fishery by snorkeling with maximum depth of 15 meters is not reaches this part of the stock. Finally, it is noticeable the importance of the establishment of management strategies for the exploitation of O. insularis different of the ones used for O. vulgaris, once the species have distinct biological features

Biologia reprodutiva de Mimus gilvus (Aves: Mimidae) em área de restinga no nordeste do Brasil

The thrush beach, Mimus gilvus (Aves: Mimidae) is a passerine widely distributed in Central and South America. In Brazil occurs mainly in the areas of the resting and vegetation near the beach. In southeastern Brazil this species has disappeared, mainly due to urbanization. Many attributes of their reproductive biology are unknown, especially in relation to reproductive success. During the years 2010-2011, 2011-2012 and 2014-2015 were made visits to the area of restinga forest in Centro de Lançamento da Barreira do Inferno (CLBI), located between the cities of Natal and Parnamirim-RN (5 ° 54'S 35 ° 10'W ) where they were made systematic searches to trying describe reproductive biology of the characteristics of M. gilvus, estimate their reproductive success using the Mayfield method, and identify the main factors that influence their reproductive success in environment the resting. For this, forty fifth active nests monitored were used. Only during the breeding season of 2011-2012 and 2014-2015 were made systematic visits to the study area. The reproductive period ranged August to March. Clutch size ranged from two, three and six eggs (n = 22). Broods of two eggs were more common, with an average of eggs laid per nest of 2 ± 0,51 (n = 20 nests). The incubation period was approximately 13 ± 1,9 days (n = 11 nests). The period of stay of the nestlings was approximately 11 ± 1,6 days (n = 9 nests). With approximately 11 days old the nestlings were able to leave the nest. The apparent success was 37,8% and the success estimated by Mayfield method was 26,6%. Predation was the main cause of loss of nests in the study area. The daily survival rates (TDS) were obtained from 0,9593 incubation and 0,9313 for nestling period respectively. Survival estimates for each period was 0,5827 for incubation and 0,4571 for nestling period. The cumulative average rainfall for each month influenced negatively the hatching rates of M. gilvus nests. In addition, the number hatch eggs among the most rainy season (rainy season) and the period of lowest rainfall (dry season) were different. The number of lost nests of M. gilvus was lower in scrubs than cactus, which may account for the largest number of nests of this species found in scrubs. Survival rates in nestling period were lower compared with the incubation period. The fact that the survival rates nests of M. gilvus be lower in the nestling period compared to the incubation period may result from increased activity of adults during this phase of the nest, which in turn would increase predation rates. M. gilvus seems to avoid the rainy season during their reproduction, concentrated most of their nests in periods of low rainfall.