School of Biological Sciences, University of Wales
Singleton Park, Swansea. SA2 8PP
The Kefalonian Marine Turtle Project (KMTP) was established in 1996 to research and conserve the sea turtle population of Kefalonia. The principal aims of the KMTP were to conduct a short-term biological assessment of the rookery, identify the major threats to the population and to encourage the establishment of a local conservation group which would remain active after the short term goals were achieved. This report outlines the principal findings from 1996 to the present, and explains how sea turtle conservation on the island will continue into the future.
The Island of Kefalonia
The island of Kefalonia is one of the seven Ionian islands which lie to the west of mainland Greece. As in the rest of Greece, the only species of sea turtle to nest on Kefalonia is the loggerhead Caretta caretta. The main nesting beach is Mounda, situated on the southwestern most tip of the island. Additional nesting activity albeit on smaller scales, has been identified on up to 20 of the southern beaches.
The Sea Turtle Population of Kefalonia
Although the KMTP was only active between 1996-1998, sea turtle research on the island has been carried out since 1984. This was principally conducted by the Marine Turtle Research project which ceased in 1995. From 1984 to the present day, 145 females have been associated with Mounda beach. The number of nests each season, and respective females can be seen in Figures 1 and 2.
Figure 1. Number of Nests per Season, Mounda beach, Kefalonia. Figure 2. Number of Nesting Females, Mounda beach, Kefalonia
From these graphs it is evident that the numbers of females visiting Mounda beach has varied greatly over the years of monitoring. This may be attributable to the long inter-nesting period of loggerhead turtles estimated at two to three years. This infers that the high numbers consist of the same individuals returning, and those present in the 'low' years are either exhibiting a longer cycle or are out of synchrony with the rest of the population. It is also interesting to note that 1998 was the first season since 1995 that the number of nests on Mounda were seen to increase. This was an extremely promising sign and is the first indication that the decline in nesting figures over the past few years may be part of a cycle and not merely a decline in reproductivety active females.
Nonetheless, when compared to other major rookeries around the Mediterranean, the number of sea turtles nesting on Kefalonia is indeed modest. However, the research conducted by the KMTP has shown that the site is important in terms of sea turtle conservation for the following reasons:
- Lack of Predation - On Kefalonia, there have been no recorded incidents of depredation of nests or predation of hatchlings. This means that a high proportion of the nests are able to develop to completion, and all successfully emerged hatchlings reach the sea allowing good potential recruitment into the future nesting population.
- Site Infidelity - One of the most interesting findings to come out of Kefalonia is the discovery that turtles tagged elsewhere in the Mediterranean, predominantly Zakyrithos and the Peloponese coast, have been seen to nest on Mounda beach. This opens up some interesting questions regarding the genetic isolation of the Kefalonian population and nesting beach infidelity. More importantly, in the event that other sites around the Mediterranean become unsuitable for nesting, Mounda Beach may serve as a refuge for turtles displaced from these areas.
- Foraging Grounds - Two possible foraging grounds have been identified in the vicinity of Mounda beach. These are Kakava reef running off Mounda point and the area between the village of Katelios and Koroni beach. Of most interest with respect to these sites is the observation of turtles tagged outside Greece e.g. Malta. Additionally, it has become apparent that the causeway running across Katovrethes lagoon at Argostoli is a frequent foraging ground for male sea turtles.
- Long Term Population Study - Large annual fluctuations in nesting activity necessitate long term monitoring of beaches to derive average population estimates. As such, the fourteen year saturation tagging programme conducted on Mounda beach by the MTRP and KMTIP, combined with the modest size of the population, makes this one of the longest and most useful population censuses in the Mediterranean.
- Intermittent Hatching/Emergence - In general, hatchling sea turtles emerge from nests in a single event, with a number of 'stragglers' following over the next few days. However, at certain sites around the world, a prolonged period of 'intermittent emergence' occurs. For example, on Kefalonia it may take up to 20 days for all hatchlings to successfully emerge from a single nest. Work carried out during 1998 suggested that this intermittent emergence may in fact result from intermittent hatching as a result of varying thermal conditions within the clutch, thus increasing our knowledge of Mediterranean loggerhead reproductive biology.
Sea Turtle Conservation
On Kefalonia, the principal threats with regards to sea turtles generally relate to the impingement of tourism into critical habitats, and the loss of reproductivety active adults through entanglement in fishing nets. With respect to the former, owing to the low nesting density on Mounda beach, it has been impractical to suggest that the site be designated a national park. Therefore, our efforts have been to forge close links with the local communities and administration on Kefalonia to promote the con ept of sustainable development. Such an approach would allow the local economy to continue to grow without the degradation of important natural assets such as the sea turtles and their habitat. The principal problem we faced was the misorienation of hatchlings as a result of artificial lighting As such, low-tech solutions were put on the table which would be of no inconvenience to the hoteliers yet would pose no threat the turtles. We are pleased to announce that talks have been planned on Kefalonia regarding the implementation of alternative lighting strategies that would go a long way to alleviating this problem. With regards to the problem of incidental bycatch, this matter is of extreme sensitivity as such work in this area was conducted by the local conservation group, many of whom were fishermen themselves. This is a long process, but recent reports from Kefalonia suggest that a sensitisation of many fishermen Is beginning to have positive effects.
At the national and Inter-Governmental level the conservation activities were conducted in close co-operation with MEDASSET. For her work in this field, we would like to extend our sincerest thanks to Mrs Lily Venizelos whose efforts have been invaluable. Furthermore, thanks must be conveyed to the British Chelonia Group for their continued support of the KMTP by which enabled us to produce and distribute our 1996, 1997 and 1998 annual reports, copies of which were sent to the Ministry of Agriculture in Athens.
At the grass roots level, the KMTP worked very closely with the local communities on Kefalonia. As a result of this, a local initiative in 1996 led to the formation of the Katelios Group for the Research and Protection of Marine and Terrestrial Life. This group was formed from members of the local community who worked alongside the KMTP in its various research and conservation programmes. The Katelios Group were particular successful in raising local awareness via their schools education programme and the recent establishment of a environmental centre in the village of Katelios informing local inhabitants and tourists of key environmental issues in the area. It is this success which has prompted the KMTP to wind down its work on the island. As with similar conservation groups, one of our primary conservation goals of the project was to encourage the formation of a local conservation group that could take over once the project had achieved its short-term goals. As such, we are extremely pleased to hand over the reigns to the Katelios Group and wish them the best of luck in the efforts to find a sustainable future for the sea turtles of Kefalonia.
Testudo Volume Five Number One 1999