Olaya-Restrepo et al.: Estimation of growth parameters of Holothuria arguinensis from South Portugal 
5 
Total length (cm) 
Figure 2 
Length-frequency distribution of Holothuria arguinensis sampled inside 
the Ria Formosa lagoon in southern Portugal between November 2012 and 
March 2014. 
for these models are the following: 1) species reproduce 
and recruit once per year; 2) species reach a specific 
size; and 3) species grow isometrically. Most commer¬ 
cial sea cucumber species fulfill the first 2 assump¬ 
tions, but usually they do not exhibit isometric growth. 
In the case of H. arguinensis, allometric growth has 
also been reported (Gonzalez-Wangtiemert et al., 2016). 
For this reason, comparisons of growth rates from dif¬ 
ferent commercial species must be regarded with cau¬ 
tion; most of them do not show the isometric growth 
assumed by the model. 
Faster growth rates may have important and posi¬ 
tive effects on the survival of a species, primarily under 
high stress conditions and in disturbed environments 
(Morgan, 2012). Achieving a larger size rapidly could 
be an adaptive advantage: larger sea cucumbers would 
be capable of moving and stabilizing themselves in 
more mobile sediments, such as sandy substrates, and 
Sampling time unit 
Figure 3 
Growth curve from a von Bertalanffy model with a Hoening function for seasonal growth fitted, 
by using electronic length-frequency analysis (ELEFAN), to length-frequency data of Holothuria 
arguinensis sampled inside the Ria Formosa lagoon in southern Portugal between November 
2012 and March 2014. The gray bars indicate running average frequencies (Pauly, 1987). Re¬ 
sults for parameters of the Hoenig seasonal von Bertalanffy growth model were 0.88 for the 
growth coefficient (K), -0.30 for the time when the average length was zero ( T 0 ), 1.00 for pa¬ 
rameter C, which expresses the relative amplitude of the seasonal oscillation in growth, and 
70.00 for the asymptotic length (L„). Sampling time units are the relative time units (months) 
during data collection. A time unit of 0 represents the month in which sampling started (No¬ 
vember 2012), and a value of 1 corresponds with the 12th month of sampling. 
