Benthic impacts of recreational divers in a Mediterranean Marine Protected Area
Beatriz Luna
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Carlos Valle Perez
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Jose Luis Sanchez-Lizaso
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B. Luna, C. V. Pe rez and J. L. Sa nchez-Lizaso: Department of Marine Science and Applied Biology, University of Alicante
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PO Box 99 E-03080
The features of many Marine Protected Areas (MPAs) have increased scuba diving tourism in these areas. Impacts caused by recreational scuba activity vary widely among different divers with differing underwater behaviour. We studied diver underwater behaviour, the effects on the natural environment, and the characteristics that may influence diver behaviour. In all, 181 recreational divers were followed, and contacts and the effects produced were recorded. Information on diver profile and dive features was recorded. Field sampling revealed that 175 of the divers observed (96.7%) made at least one contact with the seabed, with a mean contact of 41.20 + 3.55 (mean + s.e.) per diver per 10 min. Flapping was the most frequent type of contact, and the main damage by this action was to raise sediment. Contact with the seabed was greater for males than for females, inexperienced divers than for experienced divers, camera or lantern (dive light) users than for non-users, and divers unaccompanied by a dive leader or who had not been briefed about avoiding seabed contact before undertaking a dive than for accompanied or briefed divers. A greater understanding of the causes of harmful behaviour may be useful for stricter management, reducing diving damage and assuring the sustainability of this activity in MPAs.
Introduction
For decades, the creation of Marine Protected Areas (MPAs) has
been considered to be the only way to restore natural communities
and to protect marine ecosystems (Milazzo et al., 2002). New MPAs
are being established around the world (Ballantine, 1995), and
marine-based tourism is a rapidly growing industry (Ribera,
1991; Boudouresque and Ribera, 1995; Davis and Tisdell, 1995).
The aesthetic appeal of MPAs and the facilities they provide,
together with the increased public awareness of nature, all
contribute to creating massive tourism in MPAs (Ribera, 1991; Richez,
1991, 1992, 1993; Capella` et al., 1998; Badalamenti et al., 2000).
In the past 20 years, the number of visits to MPAs has increased
globally (Dixon et al., 1993; Hawkins and Roberts, 1994; Kelleher
et al., 1995), with an associated increase in the rates of
participation in marine recreational activities, such as snorkelling,
scuba diving, or boating (Tabata, 1989, 1992; Dignam, 1990;
Marion and Rogers, 1994; Davis and Tisdell, 1995). New
technology and the consequent safety improvements have greatly
increased the number of recreational divers (Davis and Tisdell,
1995), as well as the extent of this activity around the world
(Hawkins and Roberts, 1992).
Scuba diving may result in the deterioration of benthic
communities, because divers can easily damage marine organisms
through physical contact with their hands, body, equipment, and
fins (Talge, 1992; Rouphael and Inglis, 1995, 1997; Tratalos and
Austin, 2001; Zakai and Chadwick-Furman, 2002; Pulfrich et al.,
2003; Uyarra and Co te, 2007). Although the damage produced
by individuals is usually minor, there is some evidence that the
cumulative effects of the disturbances can cause significant
localized destruction of sensitive organisms (Garrabou et al., 1998;
Hawkins et al., 1999; Plathong et al., 2000). There is a bigger
problem when the diving activity focuses on MPAs. In some
cases, the effects of a large number of divers in a few places in a
marine reserve can be contrary to the main objectives of the
creation of the MPA (Davis and Tisdell, 1995, 1996; Coma et al.,
2004; Hawkins et al., 2005). However, some authors state that
the impact of divers at a site may be influenced more by their
experience and behaviour than by the number of people who
frequent the site (Davis and Tisdell, 1995; Rouphael and Inglis, 2001;
Barker and Roberts, 2004).
The relationship between diver behaviour and their impact on
marine communities has been widely studied in coral reef areas
(Caribbean, Red Sea, Australia), but more seldom in temperate
systems. The main objectives of our study were to (i) characterize
diver behaviour according to a diver profile, and (ii) evaluate and
quantify their effects on the Mediterranean benthic community.
We provide an estimate of the damage rate of divers on the
benthic communities, demonstrate the relationship between
diver behaviour and profile, and the dive characteristics, and
illustrate the most important damaging factors to propose educational
tools to help reduce the negative effects.
Material and methods
Study area
The study was carried out at the Sierra Helada Marine Park
(SHMP; 4920 ha), which is located between Altea and Benidorm
(Alicante, Spain; Figure 1) and includes the Benidorm and
Mediana Islands, the Galera and Olla reefs, the surrounding
waters, and the adjacent mainland coast. The Posidonia oceanica
seabed in the Sierra Helada Marine Park (...truncated)