Data Library

Eastern Pacific Pelagic Fisheries: Definitions and Explanations

Variables as they appear on the outline, in alphabetical order, followed by explanations:

    anchoveta
      catch
        nominal catch Total monthly anchovy catch of the Peruvian fishery in tonnes. Values are multiplied by 1.2 to compensate for unrecorded catches. (The data consists of the northern/central stock, 4 S to 14 S.)
        condition factor Anchovy condition factor (c.f.) for the months in which they could be computed from catch samples. The c.f. values estimated using SST data are not included. Therefor, correlations of c.f. and SST are legitimate. This variable is not to be confused with catch coefficient. (The data consists of the northern/central stock, 4 S to 14 S.)
        distribution by cm length class Per cent catch composition, or length-frequency data per centimeter length class. (The data consists of the northern/central stock, 4 S to 14 S).
      eggs
        daily reproductive output The egg production, or reproductive output (RO) is estimated using the following variables: biomass of male and female anchovies, fraction of mature fish, size-specific factor relating anchovy fecundity per unit weight to length, number of spawnings per month, fraction of females in parent stock, and relative batch fecundity.
        mature female biomass Biomass of anchovies capable of spawning. Units are tonnes * 10^6.
        egg development time Egg development time is estimated in D (days). It is estimated using the following equation: log10(D) = 6.953 - 4.09log10(T+26), where T is the SST in degrees C.
        estimated mortality Estimated using the following equation, explained below: Nd = R e(-ZD). Z refers to the estimated mortality.
        map standing stock These estimates were derived by planimetry. The following equation estimates egg standing stock. Nd is the egg standing stock, R is the initial size of a given age group, or cohort, of anchovy eggs, and D represents days. Nd = R e(-ZD).
        mortality Mortality, or actual measured Z. Z often refers to the composition of the fishing mortality and the total natural mortality. The data is spotty because this variable has not been measured on a regular basis.
        anchoveta parent stock Anchovy parent stock represents estimates of parental biomass in tonnes * 10^6.
        sardine biomass Estimated biomass of sardines in tonnes * 10^6.
      Peru I
        biomass distribution by cm length class
        egg production
        mature female biomass
        mature male and female biomass
        recruits
        total biomass
      Peru II
        biomass distribution by cm length class Estimated total biomass of anchovies residing within similar length classes (not necessarily similar cohorts). The shortest length class considered, or recruitment class, ranges from 3.75 to 4.75 cm. Rarely do anchovies achieve the largest length class of 19.75 to 20.75 cm. For explanations concerning how these estimates are formulated, refer to New Estimates of Monthly Biomass, Recruitments and Related Statistics of Anchoveta (Engraulis ringens) off Peru (4-14S), 1953-1985, found in The Peruvian Upwelling Ecosystem: Dynamics and Interactions.
        egg production The egg production, or reproductive output (RO) is estimated using the following variables: biomass of male and female anchovies, fraction of mature fish, size-specific factor relating anchovy fecundity per unit weight to length, number of spawnings per month, fraction of females in parent stock, and relative batch fecundity.
        mature female biomass Virtual Population Analysis III (VPA III) routine of the ELEFAN III program estimates of anchovy biomass off the coast of Peru (4 S - 14 S). For further information on the model, I suggest the following article, New Estimates of Monthly Biomass, Recruitments and Related Statistics of Anchoveta (Engraulis ringens) off Peru (4-14S), 1953-1985, found in The Peruvian Upwelling Ecosystem: Dynamics and Interactions.
        mature male and female biomass See above.
        recruits "Recruitment is defined most commonly as the number of fish of a single year group entering the exploitable phase of a stock in a given period by growth of smaller individuals. It is defined also as the number of fish from a single year group arriving in an area during a given period where (when?) fishing is in progress, even though the fish may be so small that the chance of capture may be negligible (e.g., at the time that larval stages descend to the bottom)" (Royce 236). "Recruitment to a stock depends on (i) the size of the spawning stock and (ii) the survival of the eggs and larvae" (Pauly & Soriano 155). On Peru II recruitment: "Fig. 6. Time series of recruitment (of fish ranging from 3.75 to 4.75 cm, slightly less than 3 months old) into the anchoveta stock, January 1953 to December 1985. Monthly recruitment showing increasing variability, from the late 1950s to 1970, probably due to increasing fishing pressure and leading to recruitment collapse in early 1971, prior to the onset of the 1972-1973 El Nino. Smoothed data (using a 12-month running average), showing that the 1960s, which saw the buildup of the fishery, may have been a period of exceptionally and steadily high recruitment" (Pauly & Palomares 203). The recruitment data in this dataset represents the number of 3-month old fish recruited to the fishery. "The population estimates (in numbers) of the smallest class considered here (3.75 to 4.75 cm) are here defined as 'recruitment' (of fish with mean length 4.25 cm)" (Pauly & Palomares 197). "The new recruitment estimates [Peru II] differ significantly from the old estimates [Peru I], partly due to mackerel consumption acting as a surrogate for SST" (Mendelssohn 364).
        total biomass Virtual Population Analysis III (VPA III) routine of the ELEFAN III program estimates of anchovy biomass off the coast of Peru (4 S - 14 S). For further information on the model, I suggest the following article, New Estimates of Monthly Biomass, Recruitments and Related Statistics of Anchoveta (Engraulis ringens) off Peru (4-14S), 1953-1985, found in The Peruvian Upwelling Ecosystem: Dynamics and Interactions.
      predators
        nominal catch Total monthly catch of anchovies within the Peruvian fishery in tonnes. This index of nominal catch only refers to the catch of anchovies, and not the catch of the predators. Values are multiplied by 1.2 to compensate for unrecorded catches. (The data consists of the northern/central stock, 4 S to 14 S.)
        Peru I baseline natural mortality This is an estimate of natural mortality (Mo) of anchovies from the Peru I version of the VPA - ELEFAN program.
        Peru II baseline natural mortality Here is an estimate of natural mortality (Mo) of anchovies from the Peru II version of the VPA - ELEFAN program, discussed in The Peruvian Upwelling Ecosystem: Dynamics and Interactions.
        species
          abundance Abundance of anchovy predators in MAR (numbers * 10^3).
          anchovy consumption The amount of anchovies in tonnes that major predators consume per month.
          biomass Total biomass in tonnes of fish and birds within the bounds of the Peru fishery that prey on anchovies.
          numbers Number * 10^6 of certain anchovy predators in the Peru fishery.
          total consumption Total food consumption of anchovy competitors measured in tonnes per month.
        total natural mortality This is an estimation of the total natural mortality (M) of anchovies.
      yearly mean
        adult stock Total biomass of anchovies of recruitment size or greater.
        recruits See recruitment definition in the Peru II section. Note: neither VPA - ELEFAN generated dataset was used in creating this index. This refers to recruitment biomass (tonnes).
    catch yearly
      anchoveta catch Yearly anchovy catch off of Peru.
      caballa catch Yearly caballa catch off of Peru.
      human consumption
        catch for indirect human consumption by port Peru Fish catch for indirect human consumption.
        catch for indirect human consumption Peru Fish catch for indirect human consumption. This is a compilation of the catch for indirect human consumption by port.
      jurel catch Yearly jurel catch off of Peru.
      sardina catch Yearly sardine catch off of Peru.
    economics
      FOB
        FOB index Free on Board (FOB) index. Prices for Peru (US$/TM) divided by Soyameal FOB Brazil (US$/TM).
        FOB Peru Free on Board (FOB) prices for Peru (US$/TM).
        soyameal FOB Brasil Soyameal FOB for Brazil.
      prices
        fishmeal prices Weekly fishmeal prices. Fishmeal is canned fish distributed to the public for animal feed.
        soyameal prices Weekly soyameal prices. Soyameal is also animal (esp. poultry) feed.
      yearly
        capacity
          number of boats This index is the total number of fish, flour and oil boats that comprise the Peru fishery fleet.
          number of plants This index is the total number of fish, flour and oil related factories used by the Peru fisheries.
          ship hold This index is the total capacity of fish, flour and oil related ships of the Peru fishery fleet.
          total capacity This index refers to the total capacity of the Peru fishery.
        exports total fish, flour, and oil exports
    environment
      absorbed solar radiation Total absorbed solar radiation is an upwelling-related parameter. It is measured in Watts per meter cubed per day.
      coastal
        CDM primary production A few notes on CDM and VDM: The Constant Depth Model (CDM) is less complex and yields larger estimations of primary production that the Variable Depth Model (VDM). CDM and VDM estimates agree more closely during cooler events (Mendo 71). The CDM model uses the coastal parameter settings and the VDM used with oceanic parameter settings do not match the observed primary production as found by the C14 method (73). The CDM model used with oceanic parameter settings and the VDM used with coastal parameter settings do not match the observations relatively well (76). Now to CDM primary production: uses coastal parameterization, CDM, and upwelling from Trujillo to estimate new production 1953-1982. The model does not describe primary production as used by the C14 method.
        flux derived
          CDM NO3 First a few notes on the flux derived data. Nitrate fluxes are converted to a new primary production by the Redfield ratio and a global efficiency factor of .75 (68). For further explanation see Time Series of Upwelling Nitrate and Primary Production off Peru Derived from Wind and Ancillary Data 1953 - 1982, Mendo, Bohle-Cabonell and Calienes in The Peruvian Upwelling Ecosystem: Dynamics and Interactions. Now to CDM NO3: assumes a homogeneous (NO3) and a fixed upwelling depth of 60 meters.
          Conc*TrujUp_CDM This index assumes a fixed upwelling depth of 60 meters as well as the upwelling index based on winds off Trujillo.
          Conc*TrujUp_VDM This index assumes (NO3) increases with depth and upwelling varies based on winds of Trujillo.
          VDM NO3 This index assumes (NO3) increases with depth and upwelling varies.
        VDM primary production This index uses coastal parameterization, VDM, and upwelling from Trujillo to estimate new production (1953-1982).
      laskar events Lasker events affect upwelling. This index refers to the number of laskar events per month.
      mean relative cloud cover Mean relative cloud cover is another upwelling-related parameter.
      NO3
        60 km offshore This index uses regression of spatial SST and local SST to estimate (NO3) in the oceanic (>60km) surface water. log((NO3) at surface) = log(A) - B * log(SST). "a" and "b" vary with offshore distance.
        60 km offshore This index uses regression of spatial SST and local SST to estimate (NO3) in the coastal (<60km) surface water. log((NO3) at surface) = log(A) - B * log(SST). "a" and "b" vary with offshore distance.
        thermocline Estimated (NO3) at the thermocline.
      oceanic
        CDM primary production This model uses oceanic parameterization, CDM, and Bakun's upwelling to estimate new production (1953 - 1982).
        flux derived
          CDM NO3 This assumes a homogeneous (NO3) and a fixed upwelling depth at 60km.
          Conc*Bakun_CDM This assumes a homogeneneous (NO3) and a fixed upwelling depth at 60km as well as the upwelling based on ship measurements from 4 S to 14 S collected by Bakun and Mendelssohn.
          Conc*Bakun_VDM This assumes (NO3) increases with depth and upwelling depth varies based on ship measurements from 4 S to 14 S collected by Bakun and Mendelssohn.
          VDM NO3 This assumes (NO3) increases with depth and upwelling depth varies.
        VDM primary production This index uses oceanic parameterization, VDM, and Bakun's upwelling to estimate new production 1953 - 1982. The model does not describe primary production as observed by the C14 method.
      primary production This relies on the correlation of the depth of the 14 degree C isotherm, (NO3) at 60 meters and a fixed width upwelling zone. Mendo et. al show that this model makes too many assumptions to accurately estimate potential production.
      rossby radius The rossby radius is the actual width, in kilometers, of the Eastern Pacific upwelling region. It, along with the rest of the environmental variables, is upwelling-related.
      sea level anomalies These indices are monthly recorded sea level heights for various stations along the western South American coast.
      southern oscillation index The southern oscillation index (SOI) is a measurement of the pressure differences between Tahiti and the Darwin Islands. It is the "Southern Oscillation" part of the now common El Nino term, ENSO.
      sea surface temperature These indices are monthly recorded sea surface temperatures (SSTs) for various Ports of Peru.
      thermocline depth The thermocline depth refers to the depth at which the water temperature is 2 degrees Celsius cooler than it is at the surface.
      turbulence index
      upwelling Upwelling indices are based on the alongshore component of wind stress on the sea surface which is converted into offshore Ekman transport in cubic meters per second per meter of coast. Alongshore component is computed as Ta = ?Ty - BTx. Ty is the northward stress component, Tx the eastward stress component, ? is cos(theta), B is sin(theta) for Peru ?= .8829 and B = .4695.
      velocity This index is derived from ocean upwelling divided by thermocline.
      weekly NINO12 Weekly NINO12 refers to SSTA in the NINO 12 quadrangle. The Nino 12 quadrangle is defined as follows: 80W-90W, 0S-10S. It is a good indicator of ENSO conditions, and is closer to the Peruvian coast than the traditional Nino 3 quadrangle (90W-150W, 5S-5N) is.
      wind velocity This is a measurement of the average wind velocity around the Peruvian upwelling system.
      XBTPC1 Principal components (PC) of the EOF analysis of XBT data. This index refers to the first principal component.
      XBTPC2 See above. This index refers to the second principal component of the EOF analysis of XBT data.
    weekly fishing
      Chile
        fishing north Weekly fish catch in Northern Chile.
        fishing south Weekly fish catch in Southern Chile.
        fishing total Compilation of weekly fish catches for Northern and Southern Chile.
      Peru
        Pesca fishing See below.
          ports
            Pesca fishing Pesca is a public, government-run fishing organization set up after the early 1970s crash. FEO (Fishmeal Exporters Organization) analyzes the amount of fishmeal, and extrapolates how many fishes are caught, both in Pesca and Privates.
            Privates fishing Privates refer to private run fishery companies in Peru.
            total fishing Total refers to a compilation of Pesca and Privates. For practical purposes, Privates and Pesca shoud be combined.
        Privates fishing See above.
        total fishing See above.

Eastern Pacific Pelagic Fisheries: Bibliography

    Mendelssohn R. "Reanalysis of Recruitment Estimates of the Peruvian Anchoveta in Relationship
      to Other Population Parameters and the Sorrounding Environment," The Peruvian Upwelling Ecosystem: Dynamics and Interactions. ed. D. Pauly, P. Muck, J. Mendo, I. Tsukayama, Instituto del Mar del Peru (IMARPE), 1989.
    Mendo J. et al. "Time Series of Upwelling Nitrate and Primary Production of the Peruvian Upwelling
      Ecosystem," The Peruvian Upwelling Ecosystem: Dynamics and Interactions. ed. D. Pauly, P. Muck, J. Mendo, I. Tsukayama, Instituto del Mar del Peru (IMARPE), 1989.
    Pauly D. and M.L. Palomares. "New Estimates of Monthly Biomass, Recruitment and Related
      Statistics of Anchoveta (Engaulis ringens) off Peru (4-14D S), 1953-1985," The Peruvian Upwelling Ecosystem: Dynamics and Interactions. ed. D. Pauly, P. Muck, J. Mendo, I. Tsukayama, Instituto del Mar del Peru (IMARPE), 1989.
    Pauly D. and M. Soriano. "Production and mortality of anchoveta (Engraulisringens) Eggs
      off Peru," The Peruvian Upwelling Ecosystem: Dynamics and Interactions. ed. D. Pauly, P. Muck, J. Mendo, I. Tsukayama, Instituto del Mar del Peru (IMARPE), 1989.
    Royce, William F. Introduction to the Practice of Fishery Science, Acamdemic Press, Inc.
      New York, 1984.
    Sharp, Gary D. and Douglas R. McLain. "Fisheries, El Nino-Southern Oscillation and Upper-Ocean
      Temperature Records: An Eastern Pacific Example." Oceanography, Nov. 1, 1993, p. 13-22.
    Sullivan, Erin. "Global Sea Surface Temperatures and Fisheries."
    TBD. "A focus on Small Pelagic Fisheries."

See "dataset documentation" for a list of data sources used.

Eastern Pacific Pelagic Fisheries: Useful Filters

The function bar of the data viewer has a function titled "expert mode." Within "expert mode," one could perform various functions not listed in the filters menu. The following is a list of codes, and their purposes:
  1. T 12 runningAverage Performs a 12 month running mean on monthly data. This filter takes out seasonal signals.
  2. monthlyAverage Converts weekly data into monthly data. Correlations are easiest done on monthly data.
  3. T 12 splitstreamgrid
    dup
    T2 60. runningAverage
    sub
    T unsplitstreamgrid
     5 year filter removes decadal trends.