Reproductive biology of &lt;i&gt;Neorossia caroli&lt;/i&gt; (Cephalopoda: Sepiolidae) in the Aegean Sea

Alp Salman

doi:10.3989/scimar.2011.75n1009

Abstract

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.

Highlights

The carol bobtail squid (Neorossia caroli, Joubin, 1902) is distributed from southwestern Iceland to southern Africa in the Atlantic and the Mediterranean
Gonadosomatic indices (GSI) of both sexes were calculated for each sampling period (GSI = [GW/BW] x 100) (Gabr et al, 1998), and reproductive system indices (RSI), as a ratio between reproductive system mass (RSM) and body mass (BM) (RSI = [RSM/BM] x 100) Önsoy et al (2008)
Potential fecundity (PF) of mature females was computed as the sum of the oocytes in the ovary plus the eggs in the oviduct

Summary

Introduction

The carol bobtail squid (Neorossia caroli, Joubin, 1902) is distributed from southwestern Iceland to southern Africa in the Atlantic and the Mediterranean. The vertical distribution of N. caroli in different geographical regions has been investigated by MangoldWirz (1963a), Villanueva (1992), Salman et al (1997), Jereb et al (1998), Collins et al (2001), Lefkaditou et al (2003) and Sifner et al (2007). The most shallow distribution (81 m) was reported in the Sicily strait (Jereb et al, 1998) and the deepest (1744 m) in the western Mediterranean (Villanueva, 1992), the species is mostly abundant between 400 and 700 m throughout the Mediterranean. Mangold-Wirz (1963a) redescribed the species and discussed its systematic position, distribution and biology. Very little is known regarding the reproductive biology of the species in the Mediterranean Sea (D’Onghia et al, 1993; Cuccu et al, 2007)

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