schaef: schaef is yellowfin tuna fishery data from Schaefer 1957

In MQMF: Modelling and Quantitative Methods in Fisheries

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)

MQMF documentation built on Sept. 8, 2023, 5:14 p.m.