Biol. Mar. Mediterr. (2011), 18 (1): 124-127
M. Mereu, D. Stacca, R. Cannas, D. Cuccu
Dip. di Scienze della Vita e dell’Ambiente, Università di Cagliari,
Via T. Fiorelli, 1 - 09126 Cagliari, Italia.
[email protected]
ON THE GROWTH RINGS ON HISTIOTEUTHIS BONNELLII
(FÉRUSSAC, 1835) UPPER BEAKS
SUGLI ANELLI DI CRESCITA DEI BECCHI SUPERIORI
DI HISTIOTEUTHIS BONNELLII (FÉRUSSAC, 1835)
Abstract - The concentric rings present in the internal lateral wall of upper beaks of 109 Histioteuthis
bonnellii (Cephalopoda: Histioteuthidae) caught in the south Sardinian waters were counted. From 142
to 409 and from 176 to 437 rings were counted in males and females, respectively. No difference was
found between the number of rings among sexes (p>0.05). One year life-span was estimated in both
sexes.
Key-words: Histioteuthis, growth rings, growth curves, lifecycle.
Introduction - The knowledge about the jewel squid H. bonnellii (Férussac, 1835)
is scarce and based on a limited number of specimens analysed (Voss et al., 1998)
especially in the Mediterranean Sea (e.g. Capua et al., 2009; Cuccu et al., 2007).
Within biological information, age and growth are critical to understand the life
history of harvest species. Despite the difficulties raised by cephalopods age
estimations, ageing methods based on the study of incremental growth structures
are considered the most appropriate (Perales-Raya et al., 2010). Statoliths are the
hard structures most commonly used for age estimation, although also the beaks, for
the presence of concentric rings in the internal lateral wall, are valid tools. Recently,
this methodology has been applied on the common octopus Octopus vulgaris from
the Atlantic Sea (Hernández-López et al., 2001; Perales-Raya et al., 2010; Raya and
Hernández-González, 1998) and from Sardinian waters (Cuccu et al., in press). The
aim of this study was to establish the number of concentric rings of H. bonnellii
beaks in order to estimate the life-span of this species.
Materials and methods - Dorsal mantle length (ML, Roper and Voss, 1983) and
total weight (TW) were recorded on 59 males and 50 females of H. bonnellii collected
from 2005 to 2010 in the south Sardinian waters. Maturity stages were established
using a 4 stage maturity scale for both sexes (Immature, Maturing, Mature, Postspawning). Female with at least some oocytes in the oviducts were considered mature.
The beaks were removed and stored in 70% ethanol and, according to HernándezLópez et al. (2001), the upper parts were sectioned sagittally and cleaned with water.
The concentric rings daily deposited in the internal lateral wall were counted from
the rostral tip area to the opposite end, by using a stereoscopic microscope. The
count was performed at least five times by the same person. Data obtained from
males and females were compared by the Anova analysis.
Results - Males ranged from 24.5 to 198.0 mm ML (TW: 11.6-2409.0 g) and
females from 34.0 to 230.0 mm ML (TW: 20.6-3846.0 g). The internal lateral wall
of each upper beak revealed a pattern of concentric rings as shown in Fig. 1. The
number of concentric rings on male beaks varied from 142 to 222 (n: 10; mean:
143±23) and from 288 to 355 (n: 15; mean: 272±49) respectively in immature and
maturing individuals. From 201 to 416 rings (n: 31; mean: 334±60) were observed
in mature males and from 341 to 409 rings (n: 3; mean: 371±35) in post-spawning
On the growth rings on H. bonnellii upper beaks
125
specimens. In immature females, the number of rings ranged from 176 to 298 (n: 17;
mean: 242±38) and in maturing specimens from 270 to 377 (n: 24; mean: 326±29).
The number of rings varied instead from 355 to 437 (n: 9; mean: 406±25) in mature
females (Tab. 1).
Fig. 1 - Histioteuthis bonnellii: upper beak and detail of growth rings in the lateral wall.
Histioteuthis bonnellii: becco dorsale e dettaglio degli anelli di crescita della parete laterale.
Tab. 1 - Histioteuthis bonnelli: parameters collected for males and females at different maturity
stages. ML: dorsal mantle length, TW: total weight.
Histioteuthis bonnellii: parametri rilevati nei maschi e nelle femmine nei diversi stadi maturativi.
ML: lunghezza mantello dorsale, TW: peso totale.
Males
Females
Immature
Maturing
Mature
Postspawning
N° of
specimens
10
15
31
3
17
24
9
ML (mm)
24.5-50.0
[28.6±9.8]
50.0-107.5
[78.9±21.4]
60.0-198.0
[116.0±36.4]
135.0-150.0
[141.7±7.6]
34.0-88.0
[60.3±12.3]
67.0-146.0
[101.9±19.0]
155.0-230.0
[186.0±26.0]
TW (g)
11.6-95.0
[35.2±23.9]
83.5-629.0
[280.3±199.7]
113.5-2409.0
[730.9±542.4]
868.7-994.0
[930.2±62.7]
20.6-302.0
[140.2±73.9]
197.0-1165.0
[528.2±238.4]
1431.0-3846.0
[2260.6±695.3]
N° of
concentric
rings
142-222
[143±23]
288-355
[272±49]
201-416
[334±60]
341-409
[371±35]
176-298
[242±38]
270-377
[326±29]
355-437
[406±25]
Immature
Maturing
Mature
In brackets mean ± standard deviations
In both sexes the number of concentric rings is primarily size-dependent, with
little relationship to sexual maturation (Fig. 2). The growth curves and equations
obtained for males, females and the whole data set are plotted in Fig. 3.
No difference in the number of rings was found between sexes (Anova, F=1.92;
p=0.1691).
Overall, if we assumed that each ring corresponds to one day, the age of the
specimens analysed, ranged between 4.7 and 13.6 months (142-409 rings) and from
5.9 to 14.6 months (176-437 rings) in males and females, respectively.
Conclusions - Considering the present results, Histioteuthis bonnellii seems to
have a life cycle of about a year in agreement with the short life-span of the majority
126
M. Mereu, D. Stacca, R. Cannas, D. Cuccu
of cephalopods species (Mangold Wirz, 1963). Therefore the differences recorded in
size between males and females at the same conditions of maturity, are not due to
different ages but to a sexual dimorphism that leads the females to have bigger sizes
during the ontogenetic development.
Fig. 2 - Histioteuthis bonnellii: plot of the number of concentric rings of the upper beak against
dorsal mantle length (A, B) and total weight (C, D) for males and females at different
maturity stages.
Histioteuthis bonnellii: correlazione tra il numero di anelli concentrici del becco dorsale e la
lunghezza mantello dorsale (A, B) e il peso totale (C, D) nei maschi e nelle femmine in differenti
stadi maturativi.
Fig. 3 - Histioteuthis bonnellii: growth curves and equations of males, females and both sexes
obtained counting concentric rings in the upper beaks. ML: dorsal mantle length, TW:
total weight.
Histioteuthis bonnellii: curve d’accrescimento ed equazioni ottenute attraverso il conteggio degli
anelli concentrici del becco dorsale in maschi, femmine e intero campione. ML: lunghezza mantello
dorsale, TW: peso totale.
On the growth rings on H. bonnellii upper beaks
127
As the number of rings found in the beak of the few mature and the maturing
females is similar, we can deduce that the transition from the maturing stage to the
full maturity could be very fast as already found in other species of cephalopods
(Cuccu et al., 2003). This could partly justify the lack of finding of fully mature
females in the Mediterranean Sea (Cuccu et al., 2007). To the best of the author’s
knowledge, the female of 330 mm ML from the Atlantic Sea was the only one reported
with many oocytes in the oviducts (Voss et al., 1998). Therefore, taking into account
that our bigger specimens are so distant from that size, it would be interesting to
make the same analysis performed in this study on the Atlantic specimens in order
to understand if they have different growth patterns and life-spans.
References
CAPUA D., SARTOR P., SIRNA R., VOLIANI A. (2009) - On a large specimen of Histioteuthis
bonnellii (Cephalopoda: Histioteuthidae) caught in the northern Tyrrhenian Sea, western
Mediterranean. Boll. Malacol., 45: 23-26.
CUCCU D., DAMELE F., FOLLESA M.C., MURENU M., CAU A. (2003) - Aspetti biologici di
E. cirrhosa (Cephalopoda Octopoda) nei mari circostanti la Sardegna. Biol. Mar. Mediterr., 10
(2): 119-126.
CUCCU D., MEREU M., CAU AL., PESCI P., CAU A (in press) - Reproductive development versus
estimated age and size in a wild Mediterranean population of Octopus vulgaris (Cephalopoda:
Octopodidae). J. Mar. Biol. Assoc. U.K.
CUCCU D., MEREU M., LOI B., SANNA I., CAU A. (2007) - The squid family Histioteuthidae
in the Sardinian waters. Biol. Mar. Mediterr., 14 (2): 262-263.
HERNÁNDEZ-LÓPEZ J.L., CASTRO-HERNÁNDEZ J.J., HERNÁNDEZ-GARCÍA V. (2001) Age determined from the daily deposition of concentric rings on common octopus (Octopus
vulgaris) beaks. Fish. Bull., 99 (4): 679-684.
MANGOLD WIRZ K. (1963) - Biologie des Céphalopodes benthiques et nectoniques de la Mer
Catalane. Vie et Milieu, 13 (Suppl.): 1-285.
PERALES-RAYA C., BARTOLOMÉ A., GARCÍA-SANTAMARÍA M.T., PASCUAL-ALAYÓN
P., ALMANSA E. (2010) - Age estimation obtained from analysis of octopus (Octopus vulgaris
Cuvier, 1797) beaks: improvements and comparisons. Fish. Res., 106: 171-176.
RAYA C.P., HERNÁNDEZ-GONZÁLEZ C.L. (1998) - Growth lines within the beak microstructure
of the octopus Octopus vulgaris Cuvier, 1797. S. Afr. J. Mar. Sci., 20 (1): 135-142.
ROPER C.F.E., VOSS G.L. (1983) - Guidelines for taxonomic descriptions of cephalopod species.
Mem. Nat. Mus. Vict., 44: 49-63.
VOSS N.A., NESIS K.N., RODHOUSE P.G. (1998) - The cephalopod family Histioteuthidae
(Oegopsida): systematics, biology, and biogeography. In: Voss N.A., Vecchione M., Toll R.B.,
Sweeney M.J. (eds), Systematics and Biogeography of Cephalopods, Smiths. Contr. Zool., 586
(2): 293-372.