Bird Byctach Archives | Seabird Task Force

Cory's shearwater Calonectris diomedea eating discarded fish from a demersal Long-liner

First bycatch data collected by Seabird Task Force observers in Spain

According to previous information, May and June is the most dangerous time of the year for seabird bycatch in the Western Mediterranean and observer effort has been intensified. The bycatch of the 3 Cory’s shearwaters (Calonectris diomedea) has occurred during three monitored fishing operations. Cory’s shearwater was the main species attending at demersal long-liners during the line setting and hauling.

Cory's shearwater Calonectris diomedea accidentaly captured on a pelagic long-liner — Cory’s shearwater Calonectris diomedea accidentaly captured on a demersal long-liner. Photo: Albert Cama

The analyses of the corpses indicated that some dead birds could be active breeders, showing breeding patch. The internal analysis of one bird indicated that it was an adult female.

See breeding patch on a Cory's shearwater Calonectris diomedea — See breeding patch on a Cory’s shearwater Calonectris diomedea Photo: Albert Cama

In addition to the data collected by SEO/BirdLife observers, fishermen reported the bycatch of other seabirds during the last weeks, including another Cory’s shearwater, 2 Atlantic gannets (Morus bassanus) and up to 40 unidentified shearwaters, including a massive event of 20-30 birds. We should mention that the skipper aborted the line setting due to the big amount of seabirds attacking to bait. Two Mediterranean European shags (Phalacrocorax aristotelis desmarestii) were accidentaly captured on cuttlefish pots. Additionally, 2 Cory’s shearwaters, 2 Yelkouan shearwaters (Puffinus yelkouan) and 5 Balearic shearwaters (Puffinus mauretanicus) were found death in one beach in Tarragona, they did not showed the presence of hooks, but some injuries near the mouth, indicating Long-line bycatch.

We wish to thank the collaboration of fishermen by allowing observers on board and reporting data.

Spain

Long-liners in the Catalan coast

The Spanish team is focused in the Catalan harbours, where different kinds of long-liners operate. The main target of this project is the demersal long-liner fleet, but other boats using artisanal or pelagic long-lines also operate in the area. In fact, in the harbours where we have started our work -Llançà, Roses and Vilanova i la Geltrú- we can find boats using the different long-line types. In this blog post, we will quickly point out the differences between these similar fishing gears.As we know, long-lines are composed by a main line with several hooks attacked to it, but this general configuration can be set in a plethora of different variations which can be grouped in 3 main classes:

– Pelagic long-lines: This fishing gear requires floats to keep the gear close to the sea surface. In the Catalan coast, the fishermen generally target large pelagic predators like swordfish or tunas. They set a few thousand large hooks separated by a distance that can exceed 30 m. In this project we do not pay attention to this fishing method, since the Spanish Oceanographic Institute has an on-going long-term project with on-board observers on these fishing boats.

Example of pelagic longline configuration. Bycatch mitigation factsheet 8. BirdLife

Pelagic longliner at Torredembarra harbour. Photo: Matxalen Pauly

– Demersal long-lines: Targeting bottom species, like hake or breams, the fishing gear is sunk by the use of weights, which are combined with floats to keep the gear on the right placement for the target species. They set a similar amount of smaller hooks, which are spaced very few meters.

Longline box with the hooks, some with the bait. Photo: Pau Calero

Demersal long-liner off central Catalonia

–Artisanal long-lines: The main characteristic of this fishing gear is its small scale. This fishing gear can be very similar to demersal long-liners, but they use a few hundreds of hooks which are set in relatively shallow waters close to the coast line.

Spain

The Seabid Task Force starts on-board surveys on Spanish long-liners to assess seabird by catch

After some weeks of continuous northern winds, the 2^nd and 3^rd of March the first STF surveys on-board of demersal long-liners in Spain were conducted. One observer of SEO/BirdLife shipped on a demersal long-liner based in Llançà, one of northernmost Catalan harbours next to the Spanish-French border. The main target of the fishing boat was the Blackspot seabream Pagellus bogaraveo. These first surveys were worth improving the methodology, getting familiar with it and collecting the first data. We characterised the fishing gear configuration and effort and observed no seabird bycatch. We also enjoyed of a very tasty on-board meal, which was worth recovering strength and knowing the fishermen from a personal point of view.

Black legged kitty-wake *Rissa tridactyla* following the vessel during the operations

Only very few Yellow-legged gulls Larus michahellis, Mediterranen gulls L. melanocephalus and Kittywakes Rissa tridactyla followed the vessel during the operations. Seabirds ate discarded baits and one kittiwake stole one bait when setting but was not hooked. The shearwaters (only Mediterranean, Puffinus yelkouan) were very scarce during the operations, and most individuals were observed in coastal waters when returning to port.

During the following weeks we will keep contacting long-liner skippers and continue with on-board observations.

Spain