Variation in environmental characteristics of waters among Amazon coast oyster culture units

Abstract

Oyster culture has benefited traditional coastal communities along the Amazon macrotidal mangrove coast of Pará state in Brazil since 2006. Currently, seven oyster culture units in five municipalities are expanding production, but with no environmental monitoring, which is important for the control of the impacts of oyster culture on waters as well as for oyster management and conservation. Seasonal variation in environmental characteristics of the water was evaluated at all oyster culture units in Pará, from September to November 2013 (dry season) and February to April 2014 (wet season), to generate baseline data to evaluate future impacts and aid strategic planning, such as diversifying seed production. Salinity, dissolved oxygen, pH, oxidation-reduction potential, depth, temperature, and chlorophyll-a concentration were measured during flooding and ebbing tides, and compared between seasons and among culture units using uni- and multivariate statistics. All variables were significantly higher in the dry season, except depth, which was significantly greater in the wet season. Mean salinity, which varied from 2.4 to 46, explained most of the variation among culture units in relation to season, sampling date within each season and tidal state. However, dissolved oxygen, pH and depth were also important. Oyster culture units in Pará may be suitable for sustainable harvesting of seed/spat from the wild (lower salinity and pH), or for on-growing (higher salinity, higher pH, and greater depth). Seasonal variation is sufficient to allow both activities at most units at appropriate times of the year, which would help increase oyster production in Pará.

Reproductive cycle of the mangrove oyster, Crassostrea rhizophorae (Bivalvia: Ostreidae) cultured in a macrotidal high-salinity zone on the Amazon mangrove coast of Brazil

“…The AMMC is 480 km long with 7600 km 2 of continuous mangrove forests along the coasts of the states of Pará and Maranhão (Souza Filho 2005). The coastal environments of this region are influenced by the macrotide phenomenon, reaching tidal amplitudes of up to 7 m. This phenomenon, associated with the low slope of the local coastal plains, and two well-defined annual seasons, a rainy season (February to July) and a dry season (August to January), results in a yearly variation in coastal salinity from 0.1 to 49.2 (Sampaio et al 2020).…”

Evaluation of Paralytic Shellfish Toxins in Marine Oyster Farming and Microalgae in the Atlantic Amazon Evidences Safety but Highlights Potential Risks of Shellfish Poisoning

“…The coastal sector of the Amazon has an average annual total of precipitation that varies around 3400 mm and has the highest rainfall amplitude between the wettest quarter (February to April) and the least rainy (September to November), approximately 560 mm when compared to other regions of the Eastern Amazon [ 29 ], confirming the greater importance of rainfall for this region. Rainfall influences the inputs of sediments, organic matter, and salinity in the study region [ 31 ]. In the coastal regions of the Amazon, heavy rains during the first six months of the year (average of 326.8 mm) dilute the effects of marine influence on estuarine waters [ 32 ].…”

Comercialização De Ostras No Nordeste Paraense, Pará, Brasil

“…al., 2019;. Dentro da forma de produção da ostreicultura, o estado do Pará apresenta aspectos bastante diferenciados de Santa Catarina que é o maior estado produtor de moluscos bivalves do Brasil (MACIENTE, 2020;SAMPAIO et. al., 2020).…”