Artificial spawning substrates and participatory research to foster cuttlefish stock recovery: A pilot study in the Adriatic Sea

Abstract

This two-year study evaluates the effects of new management strategies directed at helping the recovery of Adriatic cuttlefish populations. The ability of three specially developed artificial spawning devices–seagrass collectors (SC; deployed on artificial reefs), longline collectors (LC; deployed at mussel farms), and trap collectors (TC; delivered to 19 professional and 54 recreational trap fishermen together with a dedicated logbook)–to attract egg deposition was tested. All devices were provided with a polyethylene floating rope 8 mm in diameter that served as a collector for egg deposition. Total rope length was 1,440 m in SC (2,880 segments of 0.5 m), 250 m in LC (500 segments of 0.5 m), and 250 m in TC (10 m per trap). Although the sites where SC and LC were deployed were sheltered from the action of destructive fishing gears, heavy winter storms destroyed the SC after a year. Most recreational fishermen and none of the professional fishermen provided detailed information on percent egg coverage on their collectors. The collectors attached to the three devices proved highly suitable for cuttlefish spawning, collecting more than 500,000 eggs on 2,440 m of rope. The analysis of egg diameter distribution suggested three laying events during the spawning season. The logbook data showed that egg number peaked in June. The present approach, combining habitat reconstruction and participatory research, has the potential to contribute to the recovery of cuttlefish stocks in the framework of a broader management plan.

Preliminary evidence of early Reef Cube® enhancements to mobile benthic ecosystems

“…Likewise, cuttlefish and squid may have been attracted by feeding opportunities, not only from these small fish but additionally from the higher abundances of Liocarcinus crabs and velvet crabs Necora puber. Cuttlefish and squid have been found to attach their eggs to natural fauna and flora growing on hard substrates and artificial substrata such as pots and rope material [32][33][34]. Eggs have previously been found wrapped around textile ropes attached to Reef Cubes ® in Torbay (unpublished results).…”

The potential effects of COVID-19 lockdown and the following restrictions on the status of eight target stocks in the Adriatic Sea

“…When the stock was not increasing its biomass, a sporadic fishing effort reduction might have had a negligible effect. The case of cuttlefish falls within this category and may suggest that stock rebuilding needs ad-hoc actions (i.e., more attention on restoring alive at sea the egg masses left on fishing devices or actions aimed at increasing spawning stock substrates; Grati et al, 2018).…”

Influence of Seascape on Coastal Lagoon Fisheries: the Role of Habitat Mosaic in the Venice Lagoon

“…In the Venice Lagoon this species often gathers in deeper and more dynamic lagoon channels, possibly being attracted by a variety of structured habitats that are used for spawning (e.g. rocky substrata, subtidal seagrass meadows and artificial structures) (Guerra 2006;Guerra et al 2016;Grati et al 2018). As a result, cuttlefish is traditionally pursued with a wide range of fishing gears deployed in deeper waters, including trawl nets, gill nets and traps in addition to fyke nets (Provincia di Venezia 2015).…”