Adsorption of Reactive Dye onto Uçá Crab Shell (Ucides cordatus): Scale-Up and Comparative Studies

The growing interest in using low-cost methods that use natural sources makes the study of adsorption processes increasingly frequent and common. Thus, the use of uçá crab shell (Ucides cordatus) in the adsorption of reactive dye (reactive blue 222) was studied in two systems (S1 and S2) in a finite bath, with a scale-up of 12 times and considering different forms of agitation. The biosorbent material was previously characterized from FTIR and EDX spectroscopies, SEM, physical adsorption of N2, and point of zero charge. The kinetic study allowed modeling the experimental data and defining the equilibrium time for the S1 system as 400 min, and the S2 system as 360 min. The equilibrium adsorption capacities are 3.623 mg·g−1 (S1) and 4.191 mg·g−1 (S2). The pseudo-second-order (PSO) model best described the experimental data. The favorable multilayer adsorption was confirmed for the isothermal analysis, and the Freundlich and Sips models represented the experimental data of S1 and S2, respectively. The results obtained are positive indications of the scale-up of the S2 system.

Are Crab-collectors in Mangroves of Northern Brazil (PA) Optimal Foragers?

Intensive harvesting of the mangrove crab Ucides cordatus provides subsistence for food and main or additional income to many inhabitants of mangrove areas in Northern Brazil. In order to better understand the spatial patterns of use of this natural resource as basis for sustainable resource-management, we used a combination of GPS-tracking, field observations, semi-structured interviews and participatory mapping with crab-collectors. We quantified daily working hours, traveling distance and time to, as well as collecting time inside, the patches where crabs are collected. Based on preliminary findings for three different types of transportation to the fishing grounds, we conclude that crab-collectors in our study area act in accordance with the central place optimal foraging concept in that they invest more time in traveling to areas with higher catch. We hold these findings will prove relevant for sustainably managing the use of mangrove crabs as natural resource. The parallel occurrence of different collecting-behaviours possibly releases pressure from crab stocks in the potentially depleting fishing grounds adjacent to villages, and thus, may render crab-collecting in these areas more sustainable. Detailed studies are needed to quantify the catch from different mangrove areas and to make these data useful for the sustainable management of natural resource-exploitation in mangroves.

Reconstruction of Marine Commercial Landings for the Brazilian Industrial and Artisanal Fisheries From 1950 to 2015

Landing data are the most basic information used to manage fisheries, although they are often unavailable or incomplete. The objective of this work was to reconstruct the national database of marine commercial landings for the Brazilian industrial and artisanal fisheries, from 1950 to 2015. Total landings increased strongly from 1950 to mid-1980s and suffered sharp decline in the early 1990s, mainly associated to the collapse of sardine fisheries. After that, another period of increasing landings was observed, but at a much lower rate. Industrial landings always surpassed artisanal landings in Brazilian waters, except for the beginning of the time series, when many industrial fleets had not started yet, and in the early 2000s, when a change in the methodology for collecting landing statistics was implemented in the state of Pará leading to an overestimation of artisanal landings. Artisanal fisheries have been declining since 2005, which is worrisome due to the social impact it may have on local income and food security. Regional differences were also observed, with industrial landings being always higher than artisanal landings in southeastern-southern Brazil, while the opposite was true for the northern-northeastern regions. Higher landings were observed in the southeastern-southern regions when both artisanal and industrial fleets were combined. Sardine and demersal fishes were the main resources landed by industrial fishers. Artisanal fishers caught more species than their industrial counterpart, featuring Xiphopenaeus kroyeri, Cynoscion acoupa, and Ucides cordatus. Although the fishing of Epinephelus itajara was banned in Brazil, it continues to be landed. Yet, catches of this species and others under some threat status are still not properly registered, including: Carcharhinus longimanus, Galeorhinus galeus, Sphyrna lewini, Sphyrna mokarran, Pristis pectinata, and Pseudobatos horkelii. Fishing resources not identified in previous landing reconstruction efforts, such as sea urchins and sea cucumbers, have now been reported. The database presented here should be continuously updated and improved. It is of paramount importance to resume the collection of landing statistics, including information on fishing effort, to assess the relative impact of fisheries and environmental factors on the main Brazilian fishing stocks.

Humanos e caranguejos nos manguezais do Delta do Parnaíba: histórias da paisagem

A foz do Rio Parnaíba, situada no nordeste brasileiro entre os estado do Piauí e do Maranhão, origina o único Delta das Américas em mar aberto. Esta região apresenta uma rica sociobiodiversidade e exuberantes florestas de manguezais sujeitas a forças de simplificação e contaminação características do antropoceno. O presente artigo narra transformações ocorridas no Delta trazendo a paisagem como protagonista da narrativa a partir das malhas de relações entre caranguejos, manguezais e catadores de caranguejo (caranguejeiros). Por meio de uma abordagem etnográfica que considera as relações entre humanos e outras formas de vida, o artigo evidencia a constituição de paisagens multiespécie frente a processos históricos, e também narrativos, que insistem em eclipsar as diversidades biológicas e culturais. Como contraponto, o artigo enfatiza a dinâmica viva e múltipla da constituição das paisagens do Delta.Palavras chave: Manguezais. Caranguejo-uçá. Ucides cordatus. Delta do Parnaíba. Etnografia multiespécie. Antropologia da paisagem

Can the Ucides Cordatus Fishing and the Crassostrea Gasar Creation on the Amazon Coast Make up the Curriculum of Rural Schools

The fishing and ostreiculture activities practiced in the coast of the Eastern Amazon in the state of Pará, Brazil, became important to be inserted in rural education. Thus, this literature review aimed to realize a brief theoretical discussion about the important aspects of rural education in promoting the development of fishing and osteiculture. For the accomplishment of the literary research it was sought to explain the definition in education; rural education and valorization of the rural environment; environmental education as a transversal theme; fishing and aquaculture as a teaching strategy; considerations of fishing and ostreiculture; challenges and perspectives of the teaching of fishing and aquaculture in education; and booklet as a pedagogical tool in education. In conclusion, the use of fishing and ostreiculture as a strategy for rural schools through environmental education is important to foster fishing activity in communities, as well as the sustainable use of natural resources.

Contamination in newly hatched larvae of the mangrove crab Ucides cordatus and a new perspective about trace elements transport

Mangroves are relevant ecosystems due to their ecological role, economic use, and social importance. One of the most abundant and important species in Brazilian mangroves is the exploited crab Ucides cordatus. This study focuses on this species and the aim was to evaluate the concentration of trace elements in the hepatopancreas of ovigerous females, eggs (pre-hatching and hatching stages), and for the first time, in newly hatched larvae. Ovigerous females were captured in two Southeastern Brazil mangroves (Guanabara Bay and Paraíba do Sul River’s secondary estuary) and spawning was held in spawning tanks, in the laboratory. Some females were not taken to the tanks, but they were frozen right after collection. There was no significant difference in trace element concentration between these females and those kept in the spawning tanks. Both essential and non-essential trace elements were detected in newly hatched larvae. Comparing with the adult female, the elements Zn, Cu, and Mn showed the highest concentrations in larvae and eggs. Vanadium, Cr, and Mn concentrations were significantly higher in hatching eggs than observed in newly hatched larvae, indicating the retention of elements in the eggshell. Considering the V (0.17 - 1.17 μg.g−1 dry weight), Cu (14.1 - 41.1 μg.g−1 dry weight), and Zn (235.4 - 263.9 μg.g−1 dry weight) concentrations in newly hatched larvae, with the same order of magnitude observed in suspended particulate matter (SPM) and sediments in suspension, the planktonic larval dispersion could result in the transport of elements beyond the mangrove, and their introduction in coastal waters.