Reproductive biology of <i>Neorossia caroli</i> (Cephalopoda: Sepiolidae) in the Aegean Sea

Abstract

SUMMARY: A total of 171 specimens of Neorossia caroli were collected by monthly sampling using a bottom trawl with 44-mm mesh size. The depth range of trawls varied between 150 and 550 m. The maximum size (dorsal mantle length, ML) was 41 mm for males and 50 mm for females. Seasonal gonadal stages of both sexes were examined using a gonadosomatic index. It has been observed that the pattern of ovulation of N. caroli is asynchronous and that spawning is continuous. The potential fecundity of females ranged between 317 and 685 oocytes (mean 548). As for males, the number of spermatophores per individual varied between 50 and 71 (mean 61). The smallest female with mature oocytes in the oviduct was 36 mm ML, while the smallest mature male with spermatophores was 20 mm ML. A peak in maturity was observed between July and September. Females appeared to reach larger sizes than males.Keywords: Neorossia caroli, fecundity, reproductive biology, Aegean Sea. RESUMEN: Biología reproductiva de Neorossia caroli (Cephalopoda: Sepiolidae) en el mar Egeo. -Se realizó un muestreo mensual con red de arrastre de fondo, cuyo tamaño de mallas en el copo fue de 44 mm, en el mar Egeo en el cual se recolectaron 171 ejemplares de Neorossia caroli. El rango de profundidad de los arrastres varió entre 150 y 550 m. El tamaño máximo (longitud dorsal del manto, LM) fue de 41 mm para los machos y de 50 mm para las hembras. Se examinó la variación estacional de los estadios gonadales de ambos sexos mediante un índice gonadosomático. Se ha observado que el patrón de ovulación de N. caroli es asincrónico y que su freza es continua. La fecundidad potencial de las hembras varió entre 317 y 685 ovocitos (media 548), variando entre 50 y 71 espermatóforos (61 en promedio) en el caso de los machos. La hembra más pequeña con ovocitos maduros en el ovario midió 36 mm de LM, mientras que el macho maduro más pequeño con espermatóforos fue de 20 mm de LM. Se observó la existencia de un pico de puesta entre julio y septiembre. La distribución de tallas de ambos sexos mostró que las hembras alcanzan mayores tamaños que los machos.

Reproductive biology of pink cuttlefish Sepia orbignyana in the Aegean Sea (eastern Mediterranean)

“…The reason for this phenomenon is the unidirectional impact of 3 main environmental factors that are different between the eastern and western Mediterranean: productivity, temperature, and salinity (Sonin et al, 2007). This study, combined with previous results (Salman, 1998;Önsoy and Salman, 2005;Salman and Önsoy, 2010;Salman, 2011), testifies that Mediterranean nanism can also be seen in cephalopods.…”

“…Boyle et al (1988) reported that cephalopods' first maturation length decreases from the Atlantic to the Mediterranean, and other results on other Mediterranean cephalopods such as Sepietta oweniana (Salman, 1998), S. officinalis (Önsoy and Salman, 2005), Rossia macrosoma (Salman and Önsoy, 2010), and Neorossia caroli (Salman, 2011) also demonstrated a decrease in the minimum size of mature animals from west to east that is in agreement with our results on S. orbignyana.…”

Field observations on the behavioural ecology of the stout bobtail squid Rossia macrosoma (Cephalopoda: Sepiolidae) from Scottish waters

“…As R. macrosoma is an intermittent spawner (Salman and Önsoy 2010), like other sepiolin species (e.g. Gabel-Deickert 1995;Bello and Deickert 2003;Salman and Önsoy 2010;Salman 2011), it is possible that females return to a previous egg batch to continue spawning. However, it was not possible to determine if, in our observations, already existing egg batches were laid by the same female or derived from a conspecific.…”

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“…Different numbers of spermatangia can be observed in subfamily Rossinae species, such as Rossia molleri 6-21 (Hoving et al, 2009);Semirossia.patagonica 2-19 (Önsoy et al, 2008); Neorossia caroli 1-30 (Salman, 2011), which do not contain bursa copulatrix. .…”

“…It has been reported that in general, sepiolids spawn throughout the year whether their lifetime is shorter than a year like the Sepietta oweniana or more than a year such as Neorossia caroli (Boletzky 1975;Salman, 1998Salman, , 2011Önsoy et al, 2013).…”