Page 4 - paolo

There are a lot more questions regarding the species Table 1. Measurements (in mm) of a specimen, caught at 25th
status, not only in the Adriatic Sea, but also in the entire
Mediterranean. Hopefully, this first record in the Adriatic December 2014 in Piran (Northern Adriatic).
will serve as valuable information in future research endeav-
ours. Abb. %TOT

1.3. Juvenile basking shark Cetorhinus maxi- 1 Total length TOT 2170 100
mus caught in the waters off Piran (northern
Adriatic) 2 Fork length FOR 1784 82.21

By L. Lipej and B. Mavrič 3 Precaudal length PRC 1618 74.56

On Christmas morning 2014, a young male basking 4 Pre-second dorsal length PD2 1379 63.55
shark Cetorhinus maximus (Günnerus, 1768) was caught
by fishermen in the waters off Piran (45o31.016’N, 5 Pre-first dorsal length PD1 806 37.14
13o34.081’E). It measured 217 cm in total length (TL)
(Fig. 4) and weighed 40 kg. The shark was accurately 6 Head length HDL 606 27.93
measured to the nearest mm and weighed at the Marine
Biology Station (Table 1). The animal was later delivered 7 Prebranchial length PGL 450 20.74
to the Slovenian National History Museum in Ljubljana.
8 Preorbital length POB 162,9 7,51
One of the important features, which is useful for the
recognition of young specimens, is a long hook-like snout; 9 Prepectoral length PP1 529 24.38
somehow resembling a pig like nose. The snout shape
changes with increasing age. Izawa & Shibata (1993) as- 10 Prepelvic length PP2 1127 51.94
sumed that the function of the elongated snout is related to
oophagy (unfertilized eggs) or to assist feeding due to the 11 Pelvic-caudal space PCA 341 15.71
increase of water flow through the mouth and thus higher
feeding efficiency. 12 Preanal length PAL 1421 65.48

Findings of small-sized basking sharks were rather 13 Preoral length POR 182.2 8.40
rare in the past. It is still not really clear what is the small-
est size of a free swimming specimen. The size at birth is 14 Eye length EYL 23.7 1.09
estimated between 1.5 and 1.7 m; however without any
certainty, since no specimens were accurately measured. 15 Eye height EYH 24.3 1.12
Only few data exists on small size specimens and even
many of such data are without basic biometrical infor- 16 Pectorial anterior margin P1A 382,3 17.62
mation. Recently, many small sized immature basking
sharks were sighted in Manx waters, with the smallest 17 Pectorial posterior margin P1P 275,4 12.69
among them measuring approximately 1.6 m (Hall et al.,
2013). In the Adriatic Sea, basking basking shark records 18 Pectoral base P1B 76,8 3.54
were very rare; however, after the year 1990 the num-
ber of records increased drastically. Up to date; more 19 Pectoral length P1L 185,7 8.56
than 100 records of basking shark are known from the
20 Pectorial height P1H 371,7 17.13

21 First dorsal anterior margin D1A 286,5 13.20

22 First dorsal posterior margin D1P 179,5 8.27

23 First dorsal base D1B 189,5 8.73

24 First dorsal length D1L 253 11.66

25 First dorsal height D1H 178 8.20

26 Second dorsal anterior margin D2A 75,5 3.48

27 Second dorsal posterior margin D2P 45,1 2.08

28 Second dorsal base D2B 71,2 3.28

29 Second dorsal length D2L 93,8 4.32

30 Second dorsal height D2H 42 1.94

31 Pelvic anterior margin P2A 160 7.37

32 Pelvic posterior margin P2P 121,5 5.60

33 Pelvic base P2B 141,7 6.53

34 Pelvic length P2L 174,2 8.03

35 Pelvic height P2H 124,6 5.74

36 Anal anterior margin ANA 78,9 3.64

37 Anal posterior margin ANP 38,3 1.76

38 Anal base ANB 61 2.81

39 Anal length ANL 82,6 3.81

40 Anal height ANH 33,6 1.55

41 Dorsal caudal margin CDM 603,3 27.80

42 Preventral caudal margin CPV 287,4 13.24

43 Lower postventral caudal margin CPL 173 7.97

44 Caudal fork length CFL 218,5 10.07

45 Upper postventral caudal margin CPU 347,7 16.02

46 Caudal fork width CFW 172,5 7.95

47 Terminal caudal margin CTR 84,3 3.88

48 Terminal caudal lobe CTL 109,2 5.03

49 Clasper length CL 50,1 2.31

Fig. 4: Juvenile basking shark, caught on 25th December 2014 Adriatic Sea (unpublished data). Among them approxi-
in Piran (Slovenia). mately 15% are specimens which measured less than 400
cm TL and about 6% are specimens less than 300 cm TL.

The studied specimen is already the third small sized
basking shark caught in waters off Piran in fishing nets.
The first juvenile basking shark was recorded in May 2000
when a 299 cm long specimen weighing approximately
120 kg was entangled a fishing net (Lipej et al., 2000).

Medit. Mar. Sci., 16/2, 2015, 472-488 475