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SPATIAL is a simulation package developed to model the space-time distribution of fishing intensity using alternative approaches. Three models were built with different input data requirements and output possibilities. ALLOC is a shortrun spatial bieconomic model that represents the interdependencies of smallscale and industrial fleets from different ports of origin, harvesting a target species over several fishing grounds. The space-time distribution of fishing effort of smallscale fisheries was represented, in an indicative way, as a function of estimates of the mean distance of fishing grounds from different ports. ALLOC is based on a simple logistic model for biomass, and considers the dynamic catch per unit of efffort in those grounds over the season, and the corresponding dynamic costs and revenues faced by boats from different ports.

Model YAREA introduces geographically contiguous unit areas, and the realism of age structure. It generates a virgin stock by stochastic patch distribution of recruitment, constrained by a userprovided maximum species biomass spatially distributed in the corresponding grid. YAREA models the spatial dynamics of population structure. It generates spatially distributed fishing intensity as a function of a spatially heterogenous catch per unit of effort, resulting from a nonhomogeneous distribution of population structure and age specific catchability coeficients.

Model CHART was designed to represent the short and longrun spatial dynamics of demersal fisheries as a result of interacting biological, economic, and geographic characteristics. It is an age structured model like YAREA, but incorporates distance from different ports of origin and the shortrun bioeconomic elements of ALLOC. The location of fishing sites are specified in geographic coordinates. When data are available, CHART seems to provide the most compprehensive representation of the space-time distribution of fishing intensity.

These fisheries simulation models can be very useful for training fisheries specialists and for conducting simulation experiments of a wide range of fisheries management strategies. The computer programs were developed in userfriendly interactive format to allow the user to input data and observe the results of simulation experiments.

Key Features:

  • Characteristic Model 1 (ALLOC) Model 2 (YAREA) Model 3 (CHART)
  • Time dynamic dynamic dynamic
  • Fishing grounds spatial discontinuous spatial continuous geographic
  • Coastlines distances from ports line without distance geographic w/distance
  • CPUE per ground input output output
  • CPUE within ground homogeneous heterogeneous heterogeneous
  • Distance from ports input not specified output
  • Fleets input input (effort) input
  • Fleet dynamics (longrun) output not specified output
  • Fleet dynamics (longrun) not specified not specified output
  • Gears not specified constant constant
  • Fishing intensity output output output
  • Species confined to: fishing grounds unit area unit area
  • Recruitment not specified stochastic stochastic
  • Age structure not specified endogenous endogenous
  • Growth not specified input input
  • Natural mortality not specified input input
  • Fishing mortality not specified output output
  • Migration not specified not specified not specified
  • Cost of effort input not specified input
  • Revenues per fleet output not specified output
  • Dynamic profits output not specified output

System Requirements:
SPATIAL was developed for our IBM PC or 100% compatible using Quick Basic compiler (Microsoft Registerd TM).

In order to use this program there is a set of software and hardware requirements which are listed as follows:

  • Operating system; MSDOS, version 2.0 and up.
  • Computer type: PC, AT, XT, PClaptop, notebook, 286, 386 or 486 with at least 640 K RAM.
  • Disk drives: Hardisk, one 3.5 in. or 5.25 in. disk drive
  • Monitor card: VGA
  • Printer
A single simulation experiment with model CHART may involve more than 40 minutes of execution time in a 286 computer with math coprocessor and 16 megahertz. The use of 486 computers with math coprocessor and 33 megahertz (or above) are highly recommended. With the suggested configuration, computation time is reduced to less than 10 minutes.

Statistics and Information Branch (FIAS)

Fisheries and Aquaculture Department
Food and Agriculture Organization of the United Nations
Viale delle Terme di Caracalla

Email: Fish-Statistics-Inquiries

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