Assessment of the effect of the climate variations of coastal surface water and study of Sepia officinalis spawing

Abstract

The aim of this study was to establish whether climate change affected migratory behaviour of Sepia officinalis (Linnaeus, 1758), which is an important resource for small-scale fishermen of Abruzzo region (Italy). Starting at the beginning of March until the end of April, the cuttlefish in this area migrates from deep cold water towards warmer coastal waters, where they spawn. Small-scale fishing of cuttlefish is permitted in costal waters from March to September. During the study period, between March and September 2008, both cuttlefish traps and trammel nets were used in 5 sampling areas along the Abruzzo coast to test their relative efficiency in catching cuttlefish. Trapped specimens were counted, weighed and measured, their gender and sexual maturity were also determined. The data obtained from the sampling were correlated to surface water temperature to assess possible changes in migration behaviours. The obtained data show that during the first months of migration (March and April), a greater percentage of large males was caught, while females and smaller males predominated later in the year. The study also showed that surface water temperature did not reveal any significant shifts from the trend over the last 10 years. As for the efficiency of the fishing methods, traps were found to be more effective than trammel nets.

Keywords

• Abruzzo
• Adriatic Sea
• Climate change
• Cuttlefish
• Sepia officinalis
• Sustainable fisheries
• Water temperature