First description of spawning in a deep water loliginid squid,Loligo forbesi(Cephalopoda: Myopsida)

Abstract

Despite being an exploited and economically important species, little is known about the reproductive behaviour of Loligo forbesi. During a captive trial performed in a closed seawater system in the Azores, three spawning events were directly witnessed. An account of their main behavioural aspects is given. A number of behavioural components are described for the first time in this species: ‘pair formation’, ‘mate guarding’, ‘egg holding’, ‘egg touching’, ‘white arms’, ‘red accessory nidamental glands’, ‘accentuated testis’, and ‘jockeying and parrying’. The chromatic, locomotor and postural components were very similar to other coastal loliginids observed on spawning grounds. From egg masses recovered on octopus traps, we show that in the Azores spawning activity occurs at least between 25 and 144 m, but greater depths might be expected. We suggest that this squid preferentially deposits egg masses on hard structures probably hiding them in cracks and crevices of volcanic substrata. The existence of spawning aggregations is supported by several factors: (i) these spawning grounds may coincide with the fishing spots, where the exploitation seasonally takes place, given that most individuals caught by fishermen are usually mature (more than 80%); and (ii) mate guarding and jockeying/parrying by males was observed, which is a common feature of spawning aggregation areas, where sperm competition occurs. Furthermore, our results, combined with available published and non-published data further confirm L. forbesi as an intermittent spawner. We estimate that throughout their short life cycle, females of L. forbesi are able to perform up to six spawning events, each composed of an average of ≈2300 eggs.

The Azorean Loligo forbesi (Cephalopoda: Loliginidae) in captivity: transport, handling, maintenance, tagging and survival

“…Furthermore, it is important to utilize tanks which are adapted to the size of the squid, ensuring enough swimming space. Nevertheless, it is worth noting that reproductive activity occurred with resulting egg masses laid inside the tanks (Pham et al, 2009).…”

“…fin beating, forward rush, etc. ; Porteiro et al, 1990;Pham et al, 2009) but no direct lethal attacks were recorded. Nevertheless, such events increased stress levels and inking.…”

“…Nevertheless, such events increased stress levels and inking. During two of the trials, reproductive behaviour (including pair formation and egg deposition) occurred (see Pham et al, 2009). Table 1 displays the mean instantaneous coefficient of growth for all three trials.…”

“…In this paper, we report our attempt to improve the transport, handling and culture techniques for adult Azorean L. forbesi based on the methodology used previously in the Azores (Porteiro et al, 1990;Gonçalves et al, 1995;Pierce et al, 1999;Pham et al, 2009). Descriptions of some of our techniques have been previously briefly reported by Pierce et al (1999).…”

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

“…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.…”