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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]
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 ...
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.
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]
Environmental DNA or eDNA describes the genetic material present in environmental samples such as sediment, water, and air, including whole cells, extracellular DNA and potentially whole organisms. [ 13 ] [ 14 ] The analysis of eDNA starts with capturing an environmental sample of interest.
Usually refers to the age a fish can be caught and counted in nets. Population growth rate, which measures the growth of individuals in size and length. More important in fisheries, where population is often measured in biomass. Mortality, which includes harvest mortality and natural mortality. Natural mortality includes non-human predation ...
Fisheries science is the academic discipline of managing and understanding fisheries. [1] It is a multidisciplinary science, which draws on the disciplines of limnology, oceanography, freshwater biology, marine biology, meteorology, conservation, ecology, population dynamics, economics, statistics, decision analysis, management, and many others in an attempt to provide an integrated picture of ...
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 ...