Inshore spawning grounds of the squid Doryteuthis gahi suggest the consistent use of defoliated kelp Lessonia trabeculata in Central Chilean waters

摘要

Coastal spawning grounds of the squid Doryteuthis gahi were identified for the first time at three sites in Central Chile during 2014 and 2015. A total of 15 egg masses were collected from between 10 and 15 m depth and brought to the laboratory for evaluating capsular, embryonic and when possible, paralarval characters. Egg capsules from all spawning areas were similar in size (similar to 25 mm in length) and number of embryos per capsule (similar to 15). Egg-laying patterns, in addition to field observations, suggest that relatively small D. gahi may be using shallow waters in semi-protected environments to reproduce and spawn. Additionally, the differential use of healthy versus defoliated kelp Lessonia trabeculata suggests that egg-laying females selectively choose substrata that limit mechanical damage to the fragile egg capsules and that also allow for adequate water flow, which could be reduced in a mass of kelp fronds. These findings highlight the opportunistic behaviour of D. gahi which use overgrazed L. trabeculata, a condition that is widespread in areas with high herbivory pressure.