Population structure, maturation patterns and fecundity of the squid Loligo vulgaris from southern Portugal

Fecundity of the squid Loligo vulgaris, Lamarck, 1798 (Myopsida, Loliginidae) off northwest Africa

“…In Galician waters the total number of oocytes was estimated as 782-21,885 (Guerra and Rocha, 1994). Similar results were obtained for southern Portugal (1,441-14,886;Coelho et al, 1994). It can be seen that all the data on total oocyte stock are very similar to the estimation given here of the yolk oocyte stock.…”

“…More recent attempts to assess total oocyte numbers have produced estimates ranging between 782-42,446 (Baddyr, 1988;Guerra and Rocha, 1994;Coelho et al, 1994). These estimates were based on the assumption that spawning is intermittent, as with many other squid species (Guerra and Rocha, 1994), and that the number of ripe eggs in the oviducts is much less than actual fecundity.…”

“…It is evident, because Galician and Portugese samples were fixed in Gilson fluid to separate oocytes from blood vessels. These oocytes were then graded using a series of mesh size, the smallest mesh size being 0.50 mm (Coelho et al, 1994) (Guerra and Rocha, 1994). In contrast to this size, oocytes of 0.1-0.5 mm predominate in ovaries of this species (Rocha and Guerra, 1996) as in other loliginid squid (Collins et al, 1995).…”

Reproductive activity of the tropical arrow squid Doryteuthis plei around São Sebastião Island (SE Brazil) based on a 10-year fisheries monitoring

“…In males, the GAMLSS suggested the co-occurrence of two different groups, one that matures at 187 mm ML and another that matures at 290 mm ML. This kind of pattern among males seems to have been observed in Loligo vulgaris caught off southern Portuguese waters (Coelho et al, 1994), L. vulgaris and L. forbesi males in Galician waters (Guerra and Rocha, 1994) and D. plei caught by the industrial trawling off Brazil (Marques and Gasalla, 2002;Perez et al, 2002). Hanlon (1998) and Hanlon et al (2002) studying the behavior of Loligo sp.…”

“…Previous studies on the reproductive activity of D. plei in Brazil have described spatial and seasonal patterns of maturity by using the gonado-somatic index (GSI) Rodrigues and Gasalla, 2008), as has been occurring for other loliginids around the world (e.g., Loligo vulgaris reynaudii in South Africa, Olyott et al, 2006; Loligo forbesi in European waters, Porteiro and Martins, 1994;Guerra and Rocha, 1994;Rocha and Guerra, 1999;Pierce et al, 1994;Coelho et al, 1994;Pham et al, 2009; and Doryteuthis sibogae off the southeast coast of India, Neethiselvan et al, 2001). However, more recently, some generalized additive models (GAMs), based on the gonad weight, have been proposed to better understand the reproductive activity of certain European loliginid's stocks (e.g.…”