fishmethods (version 1.3-0)

lengthfreq: Calculate Length Frequencies from Marine Recreational Fisheries Statistics Survey Data

Description

A combined length frequency table for a species is generated for any combination of year(s), state(s), bimonthly wave(s), fishing mode(s), and fishing area(s) from the Marine Recreational Fisheries Statistics Survey (MRFSS) data. The analytical steps given in Recreational Fisheries Data User's Manual are followed.

Usage

lengthfreq(intdir = NULL, estdir = NULL, species = NULL,
 state = NULL, wave = NULL, mode = NULL, area = NULL,
 styr = NULL, endyr = NULL, conveq = FALSE,
 parms = c(0, 1))

Arguments

intdir

the path and main directory (in quotes) under which raw intercept sub-directories are stored.

estdir

the path and main directory (in quotes) under which catch/effort sub-directories are stored.

species

10-digit NODC species code. A complete list of species codes is provided at the MRFSS website

state

state(s) code of data to include. A complete list of state codes is provided at the MRFSS website. Atlantic and Gulf States: 23= ME, 33= NH, 25= MA, 44= RI, 9= CT, 36= NY, 34= NJ, 10= DE, 24= MD, 51= VA,37= NC, 45= SC, 13= GA, 12= FL (12

wave

bimothly wave(s) of data to include. Bimothly Waves: 1= Jan-Feb, 2= Mar-Apr, 3= May-Jun, 4= Jul-Aug, 5= Sept-Oct, and 6= Nov-Dec. Any combination of waves can be included in c().

mode

the fishing mode(s) of data to include. Valid codes will depend on year. Years 1982-2004: 3= Shore, 6= Party & Charter Boats, and 7= Private & Rental Boats. Years 2005-present: 3= Shore, 4= Party Boat, 5= Charter Boat, and 7= Private & Rental Boats.

area

area code of data to include. Valid codes are: 1= State Territorial Seas (Ocean<= 2="Federal" 3="" mi="" excluding="" inland),="" exclusive="" economic="" zone="" (ocean=""> 3 mi), 3= Ocean <=10 4="Ocean" mi="" west="" fl="" and="" tx,=""> 10 mi West FL and TX, 5= Inland, and 6= Unknown. An

conveq

logical to indicate whether a length conversion equation will be provided. If TRUE, provide the intercept and slope in parms argument below. Conversion equation is used to convert MRFSS fork length (mm) to other length measurements.

parms

vector containing the intercept (position 1) and slope (position 2) of the conversion equation

styr

the starting year of data to include.

endyr

the ending year of data to include.

Value

• Details
  a list element summarizing the selected arguments.
• Results
  a list element containing the length frequency table with one-inch length group, numbers-at-length, and proportions-at-length

Details

Raw intercept data and catch/effort estimates must be extracted using function extractMRFSS before length frequencies can be created. Length frequencies are produced with one-inch length groups identical to the MRFSS website. Before creation of the length frquency table, fork length (in millimeters) is converted to inches. The intercept and slope parameters of a conversion equation can be introduced to convert fork length into other length measurements before creating the length frequencies. Length data and harvest estimates from the catch/effort files are extracted using the argument values. Length frequencies are created for each state/mode/wave/area fished stratum and are weighted with matching harvest estimates before being combined across strata.

References

Marine Recreational Fisheries Statistics Survey - Recreational Fisheries Data User's Manual http://www.st.nmfs.noaa.gov/st1/recreational/SurveyMaterials.html

See Also

extractMRFSS

Examples

##Example of a typical specification - not a working example
dodo<-lengthfreq(intdir="C:/Temp",estdir="C:/Temp",species=8835250101,
 state=c(25),mode=c(3,4,5,7),wave=c(1,2,3,4,5,6),area=c(1,2,3,4,5,7),
 styr=2007,endyr=2007)