Olaya-Restrepo et al.: Estimation of growth parameters of Holothuria arguinensis from South Portugal 
3 
14°0'N 
8°0'N 
2°0'N 
2°0'E 
11“0'E 
20°0'E 
Figure 1 
Map of the study area showing the 9 locations, indicated by areas shaded in black, where 
Holothuria arguinensis were sampled between November 2012 and March 2014 inside 
the Ria Formosa, a coastal lagoon in southern Portugal. Sampling was conducted by vi¬ 
sual census at 3 sites: Praia de Faro to the west of the main bridge (PFW), Praia de Faro 
to the east of the main bridge (PFE), and Fuzeta (FUZ). Random sampling was conducted 
at 6 sites: Quinta do Lago (QTL), Barinha (BAR), CUL (Culatra), Armona (ARM), Tavira 
(TAV), and Cacela (CAC). 
plays an important role in the local economy by sup¬ 
porting commercial fisheries, bait harvesting, tourism, 
aquaculture, port activities, and providing a recre¬ 
ational fishing area near human settlements. The la¬ 
goon is classified as coastal waters within the scope of 
the European Water Framework Directive (EC/2000/60, 
available from website). 
Data collection 
The data were collected by 2 methods: visual census and 
random sampling. During the volunteer program linked 
with the research project “Sea cucumbers: the new re¬ 
sources for a hungry fishery” (CUMFISH) conducted by 
the Centro de Ciencias do Mar, Universidade do Algarve, 
monthly visual censuses of sea cucumbers were carried 
out in the Ria Formosa lagoon during low tides from 
November 2012 to March 2014 in 3 locations: 2 sites 
(west and east) at Praia do Faro and 1 site at Fuzeta 
(Fig. 1). In each locality, 6 transects (each 100x2 m) 
were surveyed. Three transects were surveyed by walk¬ 
ing along the coast “outside” the water and 3 transects 
were surveyed by snorkeling “inside” sea water and by 
following the edge of the low tide level. All sea cucumber 
individuals were identified to species and their total 
length registered to the nearest 0.1 cm. Measurements 
of length were recorded in situ without disturbing the 
animals, which were not touched or removed from the 
water. More details of the methods can be found in 
Gonzalez-Wangiiemert et al. (2013).The random sam¬ 
pling was conducted in 6 different locations inside the 
Ria Formosa—Quinta do Lago, Barinha, Armona, Ta¬ 
vira, Culatra, and Cacela (Fig. 1)—during February 
and March 2014. Presence (in absolute geographical 
coordinates [datum: World Geodetic System 1984]) and 
total length (in centimeters) of all sea cucumbers were 
recorded by 2 researchers walking along the intertidal 
zone during low tide and following a route with regis¬ 
tered geographical coordinates. Again, sea cucumbers 
were measured in situ. In this way, it was possible to 
sample over a wide area and later to calculate the area 
sampled. The sampling was undertaken during tides 
lower than 0.7 m, when the seagrass meadows were 
always exposed in the sampling locations. 
Data analysis 
All length data obtained from visual census and ran¬ 
dom sampling were pooled together and grouped in 
4-cm classes. Two different growth models—the non- 
