Description Format Details References
A dataset containing data collected in two bottom-trawl surveys carried out in the Portuguese coast in 1992 and 1993, and data generated and sampled from it.
A list of 9 elements
Proportions of each age class in the catch (pj
)
were calculated using classic Age-Length Keys built from
the surveys' data. Mean length at age (lmed
) was
given values close to the ones observed in the real data,
and its standard deviation (stdv
) was calculated
as suggested by Schnute and Fournier (1980).
The two catch matrices N1992
and N1993
were
generated from this data, and the F1992
and
F1993
were calculated from them.
The otoliths
list contains a total of 1000
length-stratified random samples, extracted from the
N1992
matrix. Each of these samples simulate
process of the sampling of a small subset of fish from
the total catch to analyze its otoliths for age
determination. The age data then obtained can then be
used either alone or in combination with length data to
calculate Age-Length Keys for the population.
The data is presented as a list containing the following items:
lmed. Mean length at age.
stdv. Standard deviation of length at age.
pj_1992. Proportions of each age-class in the catch (1992 survey).
pj_1993. Proportions of each age-class in the catch (1993 survey).
N1992. Number of individuals per length and age class (1992 survey).
N1993. Number of individuals per length and age class (1993 survey).
F1992. Number of individuals per length (1992 survey).
F1993. Number of individuals per length (1993 survey).
otoliths. A list of 1000 length-stratified samples taken from N1992.
Schnute, J., Fournier, D. (1980). A New Approach to Length-Frequency Analysis: Growth Structure. Canadian Journal of Fisheries and Aquatic Sciences, 37(9), 1337-1351. DOI: 10.1139/f80-172
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