Length-weight relationships of two conservation-concern mahseers (Teleostei: Cyprinidae: Tor) of the river Cauvery, Karnataka, India

Length-weight (LW) relationships are presented for two conservation-concern species of mahseer (Tor spp.) from southern India’s river Cauvery. Constructed from angler catch data, these are the first available LW relationships for the Critically Endangered Tor remadevii and the non-native and locally invasive Tor khudree. For T. remadevii, the value of b, the allometric parameter, was 2.94 (95% CI: 2.75–3.14) and was not significantly different from 3.0, indicating isometric growth (t = 0.61, P = 0.54). For T. khudree, b was greater at 3.18 (95% CI: 3.01–3.38), but with this also not significantly different from 3.0 (t = 1.91, P = 0.06). Outputs are discussed with reference to species conservation and recreational catch-and-release fisheries.

Fractal Model of the Protoplant's Appearance

Sectional model of the tree's system branches, which was published earlier, was extended on the range (0.1) of model's allometric parameter μ, relating the magnitude of the green biomass of a tree and its size (for spruce μ ≈ 1.83). The model showed the presence of a green biomass in this range. According to the statements of fractal geometry this points out a possibility to interpret the placement of green biomass as a set of photosynthesis points. In turn according to contemporary notions about endosymbiotic character of appearance of organelles in eukaryotic cell this was interpreted as begin of endosymbiosis of cyanobacteria and a host (protist). This has been modeled by the groups’ placement of growing number of points on an interval under initial limitation of the number of points per group. The limitation is connected to the initial absence in protist an infrastructure which is need for the growing number of cyanobacteria. It was demonstrated that initially in course of increasing total points number the parameter μ decreases from 1.0 to 0.25 under the fixed number of points per group and then increases to 1.0 under the fixed number of groups. This gives an initial braking (slowdown) of growth of protoplant's size (a characteristic geometrical dimension of set of points) and then exponential growth after deleting limitation of point number per group in evolution's course of host endosymbiosis similarly to higher plants. Morphological analogy of situations of begin of plant embryogenesis and begin of seed germination with the situation described by the model of protoplant appearance is discussed.

Features and Partial Derivatives of Bertalanffy-Richards Growth Model in Forestry

The Bertalanffy-Richards growth model is employed more than any other models for forest growth and yield modelling. However, its features have not completely been recognised. As a result, misunderstanding of the model still appears in some papers published in forest journals. A study by [1] is cited here as an evidence of the misunderstanding. This paper tries to explain different features of the Bertalanffy-Richards growth model based on the different conditions of the allometric parameter and introduces an assessment software to easily get the partial derivatives with respect to each parameter when more complex techniques (e.g., the Marquardt method) are employed to estimate parameters of any nonlinear models. This paper indicates that [1] study appears some unreasonable evidences of nonlinear growth models from a forestry perspective.