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Age can be determined by counting growth rings in fish scales, otoliths, cross-sections of fin spines for species with thick spines such as triggerfish, or teeth for a few species. Each method has its merits and drawbacks. Fish scales are easiest to obtain, but may be unreliable if scales have fallen off of the fish and new ones grown in their ...
Aristotle (ca. 340 B.C.) may have been the first scientist to speculate on the use of hard parts of fishes to determine age, stating in Historica Animalium that “the age of a scaly fish may be told by the size and hardness of its scales.” [4] However, it was not until the development of the microscope that more detailed studies were performed on the structure of scales. [5]
A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as well as possible hydrodynamic advantages.
Age can be determined by counting growth rings in fish scales, otoliths, cross-sections of fin spines for species with thick spines such as triggerfish, [2] or teeth for a few species. [ 3 ] [ 4 ] Each method has its merits and drawbacks.
It is an interdisciplinary method that brings together traditional field-based ecology with in-depth molecular methods and advanced computational tools. [6] The analysis of eDNA has great potential, not only for monitoring common species, but to genetically detect and identify other extant species that could influence conservation efforts. [7]
VORTEX is an individual-based simulation software that incorporates deterministic forces as well as demographic, environmental and genetic stochastic events on wildlife populations. RAMAS. Widely accepted software packages for PVA with options for age/stage structure, spatial processes, and landscape change.
Biodiversity is usually plotted as the richness of a geographic area, with some reference to a temporal scale. Types of biodiversity include taxonomic or species, ecological, morphological, and genetic diversity. Taxonomic diversity, that is the number of species, genera, family is the most commonly assessed type. [7]
At the individual level, genetic identification can enable estimation of population abundance and population increase rates within the framework of mark-recapture models. . The abundance of cryptic or elusive species that are difficult to monitor can be estimated by collecting non-invasive biological samples in the field (e.g. feathers, scat or fur) and using these to identify individuals ...