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Fish stocks indicators, which is normalized as a 0–100 proximity-to-target score, with 100 representing "at target" and 0 being furthest from the target. Stock assessments provide fisheries managers with the information that is used in the regulation of a fish stock. Biological and fisheries data are collected in a stock assessment.
It has been called "the central problem of fish population dynamics" [14] and “the major problem in fisheries science". [15] Fish produce huge volumes of larvae, but the volumes are very variable and mortality is high. This makes good predictions difficult. [16] According to Daniel Pauly, [15] [17] the definitive study was made in 1999 by ...
Fish stocks are subpopulations of a particular species of fish, for which intrinsic parameters (growth, recruitment, mortality and fishing mortality) are traditionally regarded as the significant factors determining the stock's population dynamics, while extrinsic factors (immigration and emigration) are traditionally ignored. Stocks fished ...
This means that decisions about stock management can also be made by the people doing the harvesting. [1] The best practice is to standardise the effort employed (e.g. number of traps or duration of searching), which controls for the reduction in catch size that often results from subsequent efforts. [2]
The first principle focuses on the finite nature of fish stocks and how potential yields must be estimated based on the biological constraints of the population. In a paper published in 2007, Shertzer and Prager suggested that there can be significant benefits to stock biomass and fishery yield if management is stricter and more prompt. [19]
Demersal fish – fish that live in the demersal zone. Examples are cod, flounder and snapper. Compared to pelagic fish, demersal fish contain little oil. See also bottom feeder. Demersal trawling – trawling on or near the bottom of a sea or lake. See also bottom trawling. Depletion – reducing the abundance of a fish stock through fishing.
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]
MSY has been especially influential in the management of renewable biological resources such as commercially important fish and wildlife. In fisheries terms, maximum sustainable yield (MSY) is the largest average catch that can be captured from a stock under existing environmental conditions. [21]