| schaef {MQMF} | R Documentation |
schaef is yellowfin tuna fishery data from Schaefer 1957
Description
schaef is yellowfin tuna fishery data from Schaefer (1957) It contains the year, the catch, the effort, and the cpue and was used in one of the first descriptions of a stock assessment that used a surplus production model. The catch-per- unit-effort, cpue, is a ratio cpue of the total catch divided by the total effort as thousands of pounds per day. These days such ratios tend not to be used, with individual records for each day's effort being used instead. Using individual records does not obscure the variation between different vessels, areas, depths, and seasons. Initial parameter estimates close to the optimum values for both the Schaefer model and the Fox model could be param <- log(c(r=0.24,K=2100000,Binit=2200000,sigma=0.2))
Format
A data.frame of fisheries data
- year
the fishing year from 1934 - 1955
- catch
the total annual catch, '000s of pounds
- effort
the total effort as standard class 4 clipper fishing days
- cpue
the catch '000 pounds per standard class 4 day, a ratio cpue
Subjects
surplus production modelling
classical fisheries data
Log-Normal likelihoods
Source
from Table 1 page 266 in Schaefer, M.B. (1957) A study of the dynamics of the fishery for yellowfin tuna in the Eastern Tropical Pacific Ocean. Bulletin, Inter-American Tropical Tuna Commission 2: 247-285. Obtainable from https://www.iattc.org/BulletinsENG.htm
Examples
data(schaef)
pars <- log(c(r=0.2,K=2.1e06,Binit=2.2e06,sigma=0.2))
answer <- fitSPM(pars,schaef,schaefer=TRUE,maxiter=1000)
outfit(answer,title="Schaefer, 1957 Data",digits=4)