MEPS 466:133-144 (2012)  -  DOI: https://doi.org/10.3354/meps09925

ABSTRACT: In the Western Mediterranean, the European squid Loligo vulgaris is exploited by both commercial and recreational fleets when it spawns in inshore waters. The inshore recreational fishery in the southern waters of Mallorca (Balearic Islands) concentrates within a narrow, well-delineated area and takes place during a very specific period of the day (sunset). Another closely related species, L. reynaudii, displays a daily activity cycle during the spawning season (feeding at night and spawning in the day). Using acoustic tracking telemetry, we tested the hypothesis that L. vulgaris could display a similar daily activity pattern. We conducted 2 tracking experiments during May to July 2010 and December 2010 to March 2011, in which a total of 26 squid were tagged. Our results suggested that L. vulgaris movements differ between day and night. The squid moved within a small area during the daytime but covered a larger area from sunset to sunrise. The probability of detecting squid was greatest between depths of 25 and 30 m. The abundance of egg clutches at this depth range was also greater than at the other sampled depths. The distribution of the recreational fishing effort using line jigging, both in time (at sunset) and in space (in the 20 to 35 m depth range), also supports the ‘feeding at night and spawning in the day’ hypothesis.

KEY WORDS: Acoustic telemetry · Cephalopod · Daily activity cycle · Recreational fishing effort · Egg clutch distribution