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A low-cost towed video camera system for underwater
surveys: comparative performance with standard
methodology
G. A. Trobbiani &A. Irigoyen &L. A. Venerus &
P. M . Fio r da &A. M. Parma
Received: 24 June 2018 /Accepted: 22 October 2018 /Published online: 29 October 2018
#Springer Nature Switzerland AG 2018
Abstract Technological advances in the field of under-
water video have led to an exponential increase in the
use of drifting cameras (DC) and remotely operated
vehicles (ROVs) to monitor the diversity, abundance,
and size structure of marine life. Main advantages of
DCs relativeto ROVs are their lower costs and the much
simpler logistics required to operate them. This study
compares the performance of a new low-cost DC system
equipped with a novel measuring device with that of a
standard DC bearing an array of laser pointers. The new
DC, which can be operated from a small boat, carries a
pair of parallel steel Bwhiskers^that are dragged on the
seabed within the field of view of the camera, providing
a scale for measuring and estimating the density of
benthic biota. An experiment conducted using an array
of objects of known sizes laid on the bottom showed that
its performance in terms of both size and density esti-
mation was similar to that of the standard technique
based on laser pointers. Measurement errors had a neg-
ligible negative bias (−2.3%) and a standard deviation
that ranged between 13 and 8% for objects from 25 to
110 mm in size. The whiskers offered a simplified
method for density estimation that avoids the need to
calculate the width of the field of view, thus reducing the
video processing time by around 60% with respect to the
standard method. Briefly, the new system offers an
efficient low-cost alternative for benthic ecology studies
conducted on soft or non-irregular bottoms.
Keywords Remote underwater video .Drifting camera
system .Density estimation .Size measurement .
Laser pointers
Introduction
The use of underwater video to study marine life has
gained wide acceptance in recent years (e.g., Mallet and
Pelletier 2014; Whitmarsh et al. 2017). This is mainly
because they overcome some of the drawbacks of more
traditional removal sampling techniques such as trap-
ping and trawling, which may be too costly (large fish-
ing vessels are often needed), and limited by the rough-
ness of the seabed or by fishing restrictions within
marine protected areas. Remote video techniques allow
collecting information about populations and communi-
ties in a non-destructive manner, while avoiding some of
the limitations and biases of other non-intrusive
methods such as underwater visual censuses (UVCs).
They are free from depth and diving time constraints
imposed by diving safety (Harvey and Shortis 1996;
Harvey et al. 2001a,2002), are not restricted by the
presence of dangerous fauna (Meekan and Cappo
2004), and avoid biases caused by behavioral responses
Environ Monit Assess (2018) 190: 683
https://doi.org/10.1007/s10661-018-7070-z
Electronic supplementary material The online version of this
article (https://doi.org/10.1007/s10661-018-7070-z)contains
supplementary material, which is available to authorized users.
G. A. Trobbiani (*):A. Irigoyen :L. A. Venerus :
P. M. Fiorda :A. M. Parma
Centro para el Estudio de Sistemas Marinos (CESIMAR), Consejo
Nacional de Investigaciones Científicas y Técnicas (CCT
CONICET –CENPAT), Boulevard Brown 2915, (U9120ACD),
Puerto Madryn, Chubut, Argentina
e-mail: gastontrobbiani@hotmail.com
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