Occurrence of macro-algae in the by-catch of Beach Seine Fisheries at Sakumono, Ghana

Dense growths of macro-algae contribute to primary productivity in nearshore marine environments and their abundance has been correlated with fish catch. Though the two resources are captured together in beach seine nets, macro-algae are usually regarded as a nuisance by fishermen and discarded (as by-catch). The species composition, abundance and seasonality of macro-algal species in fisheries by-catch of beach seine nets at Sakumono, Ghana were determined between November 1999 and September 2001. Data was analysed using a combination of both univariate and multivariate procedures. The species richness of macro-algae in the catch was high and appeared to vary monthly. Biomass of macro-algae in the catch was found to be low (range 0–6.7%) and formed only 7.7% of the by-catch. The significance of macro-algae in by-catch is discussed

Biomass, Mineral Elements and Protein Contents of Six Freshwater Macrophytes from Ghana

The biomass, mineral elements and protein contents of six freshwater macrophytes found in Ghana are reported in this paper. The plants are Ceratophyllum demersum (a submerged plant), Eichhornia crassipes and Pistia stratiotes (free-floating plants), Echinochloa pyramidalis and Typha domingensis (emergent plants) and Nymphaea lotus (a floating-leaved plant). The fresh and dry weights of the plants were measured and the concentration of six elements: calcium, magnesium, nitrogen, phosphorus, potassium and sodium in the tissues of the plants were determined. Calcium and magnesium contents were determined by ethylenediamine tetraacetic acid (EDTA) titration, nitrogen by micro-Kjeldahl method, phosphorus as orthophosphate after reaction with molybdate by absorption spectrophotometry, and potassium and sodium by flame photometry. The fresh weight of the plants ranged from 22 to 57 t ha-1 while the dry weight ranged from 1.2 to 12.5 t ha-1. Mineral elements varied in the plants as follows: calcium, 0.6–2.2; magnesium, 0.4–2.7; nitrogen, 1.4–3.7; phosphorous, 0.2–0.8; potassium, 0.4–5.2; and sodium, 0.4–3.4 per cent dry weight. These values are within the ranges reported by other workers from comparable freshwater environments. The ethnobotany of the freshwater macrophytes studied was discussed

Water quality at the habitat of the Podostemaceae in Ghana

The water quality and river catchment characteristics of Ankasa, Asuboni and Pawnpawn rivers in Ghana where Podostemaceae grow were determined using standard methods. The altitude of the sites ranged from 100 to 290 mabove sea level. The catchment areas for the sites vary from 35 to 171 km2. Between 10–81% of the catchment areas of the sites are within forest reserves. The study showed that the Podostemaceae in Ghana inhabit rivers with the following range of physico-chemical characteristics: pH 6.7–7.3, calcium 2.2–16.0 mg l-1, ammonia-nitrogen 0.07–0. 90 mg l-1, chloride 6.8–38.0 mg l-1, electrical conductivity 26.4–138.0 mS cm-1, magnesium 0.4–9.7 mg l-1, nitrate-nitrogen 0.1–0.6 mg l-1, phosphate 0.01–0.30 mgl-1, silicate 0-21.4 mg l-1 and sulphate 1.5–20.8 mg l-1. The results indicate the quality of water at the habitat of Podostemaceae in Ghana

The morphology, taxonomy and distribution of the podostemaceae in west africa

No Abstract

Water chemistry and the distribution of Podostemaceae in Ghana

The physico-chemical parameters of several rivers in southern Ghana were determined during the dry season.  Other environmental features, e.g. canopy cover, rock substrate type, etc. of each site sampled were also recorded.  Four Podostemaceae species were recorded in 10 of the rivers sampled.  The distribution of the Podostemaceae appeared to relate to availability of rock substrate, open canopy and some level of plant nutrients, e.g. phosphates and nitrates in the water.  Further data must be collected at the sites where Podostemaceae grow in the tropics, particularly in Africa, to enable a better understanding of the contribution of river chemistry and other environmental parameters to the distribution of the Podostemaceae.

How to get off the mismatch at the generic rank in African Podostemaceae?

The Podostemaceae are highly enigmatic plants which are restricted to submerged river-rock habitats. The availability of new material of nine taxa from continental Africa prompted this new study. Five species belonging to the genera Dicraeanthus, Leiothylax, Letestuella, Macropodiella, and Stonesia and another four species of the large genera Inversodicraea sensu stricto and Ledermanniella sensu stricto have been analysed for the first time. New anatomical and developmental data are described and illustrated by use of microtome sections and scanning electron microscopy. In parallel, phylogenetic analyses of all available sequence data of African Podostemaceae have been conducted using three plastid markers (matK, trnD-trnT, rpoB-trnC). Inversodicraea cf. bosii appears basal within the continental African clade. The remaining taxa are distributed in three, rather poorly supported, major clades which are consistent with their morphology: (1) the Inversodicraea clade is characterised by stem scales and contains members of the former Ledermanniella subg. Phyllosoma with either pollen-monads or dyads; (2) the Ledermanniella-Monad group consisting of Leiothylax, Letestuella, Macropodiella, Stonesia, and Ledermanniella species—all taxa without stem scales but showing pollen as single grains, with Monandriella linearifolia being basal to this clade; (3) the Ledermanniella-Dyad clade including Djinga, Dicraeanthus, and Ledermanniella species without stem scales but with pollen dyads. To reduce the polyphyly of Ledermanniella sensu lato (i.e. sensu C. Cusset) we propose restricting Ledermanniella to the species of the former subgenus Ledermanniella, resurrecting Monandriella as monotypic genus, and accepting the genus name Inversodicraea for members of Ledermanniella subg. Phyllosoma