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Incidental captures are detrimental, not only to sea turtles but also to fishermen, since they can result in economic loss in time and gear components as well as personal injuries during manipulation of the hooked or entangled turtles. It is therefore a matter of interest to both fishermen and conservationists to detect the fishing gears that interact significantly with sea turtles as well as the areas and times of the years when captures are more frequent. It is also necessary to take into account the practical proposals of fishermen as to how incidental capture may be mitigated, encourage them to take turtles to recovery centres and if that is not possible, to liberate the captured turtles with minimum damage.

Within the framework of a European Union LIFE project on conservation of marine mammals and turtles in Andalusia and Murcia, we interviewed fishermen in the main fishing harbours of Andalusia. Interviews were carried out at the fishing dock, when the fishing boats had returned to harbour. There are 28 fishing harbours in the study area, 13 in the Mediterranean sector and 15 in the Atlantic. Interviews were carried out in 15 harbours, selected to encompass fleets using a range of fishing gears that can be grouped into 9 categories: bottom longlines, coastal trawls, deep water trawls, driftnets, octopus pots, purse-seiners, surface longlines, trammel nets and other artisanal gear. A total of 169 interviews were carried out, with only one interview per vessel (Table 1). Approximately 9% of the total fleet was interviewed, 17% of the coastal and deep water trawlers, 8% of purse seiners, 41% longline, 43% surface drifting longline, and 4% of other categories (setting trammel nets, driftnets, octopus pots and other small scale gears). The jobs of the interviewees were 104 skippers, 57 sailors, 3 engine officers, 1 cook, 1 net sewer and 3 were retired. We asked for very simple estimates of the average number of turtles captured per year (Table 2). All the fishermen interviewed agreed that turtle incidental capture is more frequent in the summer. It must be pointed out that some fishermen (3.6 %) answered that incidental captures were more frequent formerly and that today they are rare, however, for the majority of fishermen the rate of incidental capture was estimated to be similar to past levels. Based on the testimony of the fishermen interviewed, it appears that surface long-lines interact most frequently with marine turtles, followed by coastal trawlers, purse seiners, and trammel nets (Table 2). Sea turtles captured by the purse seiners can be released without damage because they do not get tangled up in the net. Fishermen using artisanal coastal trammel nets also suggested that sea turtles incidentally captured by this gear are released in good physical conditions. There may be more concern for turtles captured by trawlers but as suggested by our survey and according to data collected by the IEO (Spanish Oceanographic Institute) onboard observers programme, incidental capture of sea turtles is rare on trawlers.

Moroccan surface driftnets (Tudela et al. 2003) and Spanish surface long-lines targeting swordfish have in previous studies been shown to be the fishing gears that interact most significantly with sea turtles in this region. Our data confirm long-lining as a major interacting fishery but we sampled only one driftnet vessel. It is important to research the factors involved in incidental capture and develop new methods to minimize impact, such as changing fishing depth, using alternative hooks and baits, etc.

During the interviews we asked the fisherman for proposals to reduce the turtle captures. Regarding proposals to minimize turtle captures by surface long-lines, 10 fishermen agreed that a type of long-lining gear called “rulo” would be the best system to avoid it, 2 said the best would be to reduce the number of attracting lights and 2 more suggested that greater enforcement of the current Spanish regulations regarding the number of hooks and the total gear length would help.

Nine of the interviewed fishermen used the long-line named “rulo”. This modified surface long-line has an increased distance between hooks (21m in traditional long-line and 90m in rulo) and is longer (30-40 miles in traditional long-line and 60-70 miles total length in rulo). In addition rulo typically has fewer than 1,000 hooks versus the traditional surface longline that have 2,500 hooks on average. Apparently fewer sea turtles are captured by the rulo gear. This may be due to the fact that the time needed to board the gear (6-7 hours) is 2-3 hours less than for traditional long-line. Consequently, the amount of time that the rulo’s hooks are in the water and available to be incidentally ingested by turtles is less than the traditional surface longline. In addition, the size of the swordfish catch seems to be higher.

Three of the long-lining fishermen noted that it is almost impossible to solve the problem of incidental capture of sea turtles as it takes place mainly in the summer when bluefin tuna and swordfish enter to the Mediterranean to spawn. Turtles, which are also more abundant in the region at this time, have similar distributions and migratory routes to bluefin tuna and swordfish.

Long-lining fishermen are not very willing to board the turtles for three reasons: they can damage the turtle when boarding it, the operation takes a long time and it can be a dangerous manoeuvre because the hook can come free and injure the fisherman, which has already happened in a some cases. Small long-lining boats fishing near the coast (Camiñas &Valeiras 2003) do take turtles sometimes to recovery centres if incidental captures has taken place at the end of the fishing operation although they complain that recovery centres are very far away.

Acknowledgements: This work was funded in the context of the project LIFE NATURE (LIFE02NAT/E/8610) of the Spanish Cetacean Society and in collaboration with the Malaga Centre of the Oceanographic Spanish Institute.

Table 1. Fishing harbours and number of interviews by gear grouping.

Table 2. Results of the interviews in terms of quantum estimated average levels of annual incidental capture rates. Key accidental capture frequency: Never= 0, Exceptional= 1 turtle per year, Rare >1<10 turtles per year, Frequent >10 turtles per year, Irregular= highly variable among years. Key: BLL- Bottom long-line, DN- Drift net, OP- Octopus pots, PS- Purse seiners, SLL- Surface long-lines, TN/A- Trammel nets and other artisanal gear, CT- Coastal trawlers, DWT- Deep water trawlers.

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