Content uploaded by Primo Micarelli
Author content
All content in this area was uploaded by Primo Micarelli on Jun 03, 2020
Content may be subject to copyright.
Content uploaded by Primo Micarelli
Author content
All content in this area was uploaded by Primo Micarelli on Dec 08, 2015
Content may be subject to copyright.
46° Congresso della Società Italiana di Biologia Marina
Roma, 10-12 giugno 2015
P. MICARELLI, E. SPERONE, G. GIGLIO, J. PECCHIA, C. ROMANO A.
SCUDERI, L. VESPAZIANI, F. MELE
1Centro Studi Squali , Aquarium Mondo Marino - loc.Valpiana Massa Marittima (GR) 58024
2University of Calabria, Department of Ecology - Arcavacata di Rende (CS)
3 University of Pisa, Department of Marine Biology (PI)
centrostudisquali@aquariummondomarino.com
Carcharodon carcharias
Abstract: Studying the behaviour of the White Shark is a recent and big challenge. Optimising the
photoidentification of White Shark dorsal fins is a basic goal, in order to compare behavioural information in both
immature and mature specimens and between females and males. During a 6 years research, from 2009 to 2014,
we observed about 296 sharks and 8 specimens were resighted several times. Data about sex, sizes, environmental
conditions and behaviours were collected. This is the first step to develop a more complex database in which
include all the observed behaviors for each shark in different environmental conditions over the years. The final
goal is to share the information we have collected with other research groups operating in other geographic areas
working on other populations of white sharks
Keywords: photoidentification, dorsal fin, behaviour, Carcharodon carcharias
Introduction: !" "#$% !# Carcharodon carcharias &'$()
$'* #'+, $'- !.%-*%*#.- ()+- *,+/. !01 -*'2
#*%#. .!-.#-'-3 "!",(% '!- $)-%4'.* 3- '. .! !1'.!(!3)
%-$+%2'!,#5-"%# '.,(%# '- (%* &! $.%$* 4%-)6!# *
&# .%##'$ !, '- !#$# ! 3 4!# '-0!#4% '!- %+!,
+%2'!,# Klimley et al., 7789 Martin 2003; '.%#((' et al., ::89
"#!-et al.::) of this vulnerable specie, included in the I.U.C.N. red list.
This information could be useful to better plan the conservation of this species. Recent
researches demonstrated that individual surface behaviour of white sharks in presence
of a bait is not a simple stimulus response reflex, but rather a complex tactical situation
with plastic responses (Sperone et al., 2012).The white shark is a much more complex
animal than imagined just 20 years ago. Recently, the possibility that the dorsal fin can
be compared for a long time, more than 22 years, was confirmed (Anderson et al.,
2010). This could represent a good tool to study single specimen for a long period,
obtaining information about the development of the behaviour in this species.
The photoidentification is a non-invasive method of mark and recapture.The dorsal
fins present particular notches in the posterior line which can became typical marks and
persist during their life. Towner et al. (2013), showed that Darwin program is suitable
for matching and cataloguing white shark dorsal fins but they consider that, without
consistent effort, it is possible that individual fins which changed would not be
successfully matched to the same individual shark: thus fin IDs from the same shark
over time can be counted as multiple individuals resulting in an over-estimation of
animals. Photographic identification remains a subjective method, since the final
decision on identification is taken by the observer based on experience and expertise
(Gubili et al., 2009). This research note reports about the first step we made to build a
larger database: this will be useful to compare the behaviour of mature and immature
sharks, males and females, over the years, and with the growth.
;8<!-3#0!#4 * '25:<%"#<:;25
46° Congresso della Società Italiana di Biologia Marina
Roma, 10-12 giugno 2015
Material and methods: During 6 Scientific expeditions managed by the Centro Studi
Squali and occurred between 2009 and 2014, 323 useful photos of dorsal fins were
collected for 296 sharks along Dyer Island in Southafrica, where an important
population of > 500 great white is yearly present (Micarelli et al. 2006; Towner et al.
2013). Data were collected between march and april around Dyer Island, 200km far
from Capetown, which hosts about 60.000 cape fur seals (Arctocephalus pusillus
pusillus), that represent the principal food resource for the local population of white
shark. With a 12m long boat, we anchored at 100m close to the island, in 8m deep
waters. Fin photos were collected using 3 digital cameras: 1 CANON model EOS 550,
with a SIGMA 70-300mm lens and 2 with CANON 18-135mm lenses. Images were
then analysed with the program Darwin and the program Photoshop. The operators
photographed the fins both sides, left and right. Operators were placed the most
perpendicular respect the sea surface. Each photo was numbered and complete with the
following additional information: date, day-time, sex and size of the shark, weather
conditions and behaviour (social, individual, predatory, investigative). Identification of
individual sharks was based on a larger pattern including not only the different notches
of the dorsal fin, but also the following characters: caudal fin features, pelvic fin
patterns, gill slashes and body patterns, presence of scars and/or ectoparasite (Sperone
et al. 2012). We assumed that at least 5 same dorsal fin notches must be present in each
resighting.
Results and conclusions: The analysis of collected photos showed that the observation
of the same animal along the years is a useful tool for behavioural studies; however
photoidentification analysis must be very detailed and must include many other
information to avoid potential mistakes. During our research, 8 sharks were resighted
(pic 1, 2), for all of them were collected also behavioural information, but results are
still not significant because number of resigthings is too low for an accurate analysis.
The challenge is to improve the database of identified and catalogued specimens.
Further investigations are needed and are actually in progress, in order to compare the
development of the behaviour of sharks over the years.
Bibliography:
ANDERSON S.D., CHAPPLE T.K., JORGENSEN S.J., KLIMLEY A.P., BLOCK B.A., (2010)
Long-term individual identification and site fidelity of white sharks, Carcharodon carcharias, off
California using dorsal fins;
GUBILI C.,JOHNSON R.,GENNARI E.,OOSTHUIZEN W.H.,KOTZE D.,MEYER M.,SIMS D.,
JONES C.S.,NOBLE L.R., (2009). Concordance of genetic and Wn photo identiWcation in the great
white shark, Carcharodon carcharias, Mossel Bay, South Africa. Mar Biol (2009) 156:2199–2207
KLIMLEY A.P, PYLE P., ANDERSON S.D., (1996). Tail slap and breach: Agonistic displays
among white sharks? In: Klimley AP, Ainley DG, editors. Great White Shark: The Biology of
Carcharodon carcharias. San Diego, CA: Academic Press, p 241_55.
MARTIN R.A., (2003). Field Guide to the Great White Shark. Vancouver: ReefQuest Centre for
Shark Research. 185 pages.
MICARELLI P., SPINETTI S., TRIPEPI S., SPERONE E., 2006. Observations about surface
behaviour of the great white shark Carcharodon carcharias (L.) versus passive preys in Dyer Island
(South Africa). Biologia Marina Mediterranea 13(2):278_79.
SPERONE E., MICARELLI P., ANDREOTTI S., SPINETTI S., ANDREANI A., SERENA F., et al.
(2010). Social interactions among bait-attracted white sharks at Dyer Island (South Africa). Marine
Biology Research 6:408_14
SPERONE E., MICARELLI P., ANDREOTTI S., BRANDMAYR P.,BERNABO I., BRUNELLI E.,
;8<!-3#0!#4 * '25:<%"#<:;25
46° Congresso della Società Italiana di Biologia Marina
Roma, 10-12 giugno 2015
& TRIPEPI S. (2012). Surface behaviour of bait-attracted white sharks at Dyer Island (South Africa).
Marine Biology Research, 2012; 8: 982_991.
Pic.1 Pic.2
;8<!-3#0!#4 * '25:<%"#<:;25
