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Alexandros A. Karamanlidis The Mediterranean monk seal (Monachus monachus), one of the rarest mammals on earth, has disappeared from most of its original range. Once an open beach dweller, the species now frequents rocky sea caves for resting and reproduction. One of the last refuges of the monk seal is in the National Marine Park of Alonnissos and the Northern Sporades (NMPANS), a 2200 square kilometre area in the northern Aegean, set aside in 1992 by the Greek Government for the protection of the unique ecosystem and, particularly, the Mediterranean monk seal. The NMPANS is divided in two zones (Fig. 1), with varying degrees of protection. Zone A Zone A includes 7 large and several smaller islets as well as the marine area surrounding them. These include Kira Panagia, Gioura, Piperi, Psathoura and Skantzoura. The Core Zone of the NMPANS is situated within Zone A and includes the uninhabited island of Piperi and a three nautical mile marine area around it. All human activities in the Core Zone, except scientific research with special permit, are prohibited. Special protection measures have been taken also for the island of Gioura, where tourists may not approach closer than 400 metres. The remainder of Zone A has fewer restrictions and is basically open to tourism and to small-scale coastal professional fisheries. Zone B This Zone includes the only inhabited island of the NMPANS (Alonnissos), several smaller islands and the marine area around them. Apart from regulations on purse-seine and trawler fishing, most other activities are permitted in this Zone (MOm 1996). Monk seal research in the Northern Sporades has been carried out sporadically since the early 1970s (Schultze-Westrum 1976). Systematic monitoring of the monk seal population of the area started in 1988, when the Hellenic Society for the Study and Protection of the Monk Seal (MOm) was founded. Since then, this organisation has become active in monk seal research, as well as in various conservation projects in the area (guarding, rehabilitation, public awareness, oceanographic surveys, etc.). Within the framework of the activities of MOm for the year 1996, the author had the opportunity to carry out a project that was partly funded by MOm. The project was designed in collaboration with the field research team of MOm and the infrastructure of MOm was utilised. The aims of the project were: Human activity in the NMPANS was monitored and recorded from 25 July to 2 October 1996, through regular patrols in the Park. The patrol-boat, Alonnissos II, with its experienced guarding crew and its accommodation facilities, offered the most favourable monitoring conditions. In the process of recording human activity, the data recording system of the guarding team of MOm was used. The system was based on dividing the NMPANS into numbered "quadrats" in order to facilitate the recording of each activity. Every time a quadrat of the National Park was patrolled, the identity, the activity and the position of boats present were recorded. Navigation instruments were often required to identify the exact position of vessels. The methodology used in the study of habitat use was based on the protocols and methods used in the monitoring programme of MOm for the monk seal population in the area. In devising the methodology of the project, avoiding disturbance to the animals was of utmost concern. The inspected caves were approached with caution, and swimming into them was decided, only when no resting animals were thought to be inside. The whole procedure of the cave inspection did not last more than 10 minutes. This method of collecting data has been used successfully in the Sporades for the past ten years (Kouroutos 1987, MOm 1990, MOm 1995b). Since in the Sporades seals exhibit a preference in using caves at night (Dendrinos et al. 1993), cave inspections were carried out during the day. Human activity in the NMPANS During this project 593 vessels of various types were recorded. In the process of information evaluation, two different boat groups were distinguished (Fig.2): More than 70% of the recorded boats were involved, in one way or another, in tourist activities. Boats travelling within the NMPANS (Fig. 3) Of the 593 boats recorded during the project, 70 were travelling at the time of the observation. Of these, 10 were distributed in Zone B and 60 in Zone A. A closer look at the position of the recorded boats reveals that all the non-prohibited coastal waters were visited by tourists and fishermen. The highest concentration of travelling boats was recorded in the coastal waters of Alonnissos, Peristera and Kira Panagia. An observation made on site and partly confirmed by the data collected, was, that the north side of Kira Panagia was, compared to the south one, the preferred travelling route. Boats anchored within the NMPANS (Fig. 4) From the total number of recorded boats (593), 453 were seen at anchor. A closer look at the position of the anchored boats shows that they were concentrated mainly in three areas. The bay of Planitis in the north of Kira Panagia (quadrat G 13) was the busiest anchorage in the NMPANS, followed by the bay of Agios Petros in the south of the same island (quadrat H 12). The number of boats recorded anchored at the island Skantzoura (quadrat O 13 and O 14) was relatively lower due to the low number of visits conducted to this island during this project. Boats fishing within the NMPANS (Fig. 5) Of all vessels recorded, 69 were observed to be engaged in some form of fishing activity. Eleven were found fishing in Zone B and 60 in Zone A. The latter number refers to professional fishermen, as Zone A is off-limits for amateur fishermen. A closer look at figure 5 shows that professional fishermen frequented all coastal waters of the Park for their fishing activities, with a slight preference for the coastal waters around the island of Gramiza (quadrat G 15) and the reef area north-east of the island of Gioura (quadrat E 16), a well known fishing ground. In addition, three fishing boats were recorded in the Core Zone, an area restricted to fishery, and the guarding team took the necessary action against them. Human activity intensity of different areas of the NMPANS In order to estimate the intensity of human activity in the protected area of the NMPANS, 77 different quadrats of the NMPANS were visited and the number of boats in each of these quadrats was recorded. The monitoring effort concentrated mainly in the highly sensitive area of the Core Zone and the areas with the highest human activity. To minimize bias, the number of boats per survey was used as an indicator for the intensity of human activity (see Fig. 6). Human activity was recorded in 28 of the 77 quadrats visited. The quadrats with the highest number of boats per survey were located at the coastal waters of the islands of Kira Panagia (G13 and H12) and Skantzoura (O13 and O14). Intermediate numbers of boats per survey were recorded at the quadrats C16, E16 and H13. The marine areas between Alonnissos and Kira Panagia, Alonnissos and Skantoura as well as between Kira Panagia and Gioura, which were used for fishing and sailing, presented low numbers of boats per survey.
Kerassountos 9, GR-55131 Kalamaria, Thessaloniki, Greece
email: karazar@vet.auth.gr
Introduction
Fig. 1: The National Marine Park of Alonnissos and Northern Sporades
Methods
Results
Fig. 2: Boat types recorded within the NMPANS
Fig. 3: Distribution of vessels recorded travelling within the NMPANS during the project
Fig. 4: Distribution of vessels recorded anchored within the NMPANS during the project
Fig. 5: Distribution of vessels recorded fishing within the NMPANS during the project
Class one = light blue had
0,045-1,495 boats per survey (bps).Class two = Yellow had
1,495-2,945 bps.
Class three = no areas found with
2,945-4,395 bps.Class four = Green had
4,395-5,845 bps.
Class five = Light red had
5,845-7,295 bps.Class six = Pink had
7,295-8,745 bps.
Fig. 6: Relative usage frequency of different areas of the NMPANS Sixty-nine cave visits were carried out and, in 16 of them, there was evidence of cave use by seals (tracks of movement on the cave beach, blood stains, faeces) (Table 1).
For the 4 caves together, the average percentage of evidence of seal presence per survey was 23% (Table 1). The data collected during this project indicate that the four caves inspected were being used in a different degree by the local seal population (Fig.7). The findings of the project allow some tentative conclusions regarding human activity in the National Marine Park of Alonnissos and Northern Sporades. Human activity in the summer months is especially high, mainly due to the presence of tourists in the area, who usually remain in the coastal, non-prohibited waters of the park. Professional fishermen working in the area usually visit the areas prohibited to tourists as well. Regarding the intensity of human activity in the different Zones of the Park, this project showed the following: The specific pattern of traffic and human activity of the marine areas of the NMPANS presented above, is similar to the activity pattern of previous years (MOm 1995a). Considering the low number of seals living in the area, the average percentage of seal presence per survey (23%) indicates an intensive cave use by Monachus monachus. The fact that from 16 recorded cases of cave use, only one animal was observed in a cave during the daylight hours, is consistent with the evidence provided by other researchers (Dendrinos et al. 1993, Matsakis et al. 1985) that the monk seal population of the Sporades uses caves mainly at night. During this project 4 "active" caves at three different islands were monitored. The monk seals showed a preference for the shelters Pip 2, Pip 4 and Giou 2 (Fig. 7). Possible explanations for this apparent shelter preference could be: 1. Human activity in the vicinity of the cave A comparison between Figures 6 and 7 shows that the caves Pip 2, Giou 2 and Pip 4 of the quadrats H20 and Z16 (quadrats with minimal human activity) were visited more often than the cave Pan 2 at quadrat H12, which is located in an area of intense human activity. Thus, it is logical to assume that monk seals reacted to human activity in the NMPANS and chose undisturbed places to rest at night. Regarding the low percentage of cave use of Pan 2, one should not suppose that the island of Kira Panagia is not suitable monk seal habitat. While monk seal tracks were not found in Pan 2, evidence of monk seal presence was found in another cave on the same island, which had the same direction of entrance as Pan 2 ( P. Dendrinos and E. Tounda, pers. comm.). According to what is known about monk seal habitat, the latter cave is less suitable than Pan 2, since the substrate of the beach is not as suitable for the seals to rest on. It does offer them, however, better protection against humans, as it has a small, narrow entrance, allowing access to the cave only by swimming whereas Pan 2 has a large entrance and the beach in it is visible from outside. In this case, one might assume that seals in search of solitude and avoidance of humans, would choose such caves during periods of intense human activity. Following the tourist season, they might likewise be expected to return to their "preferred" caves, such as Pan 2. A similar pattern of cave use has been observed in monk seals in the Ionian sea (Panou et al. 1993). 2. Wind force and direction in the vicinity of the cave ‘Human activity’ is, however, insufficient to explain the marked difference in cave use of the other three caves (Pip 2, Pip 4, Giou 2), which are all located in quadrats with minimal human activity. The difference in cave use between Pip 2 (50%) and Pip 4 (19%), which are both located in the same quadrat, is striking. In search for an explanation for the large difference in cave use between Pip 2 and Pip 4 one must consider the factors of wind, and wave force and direction. The prevailing winds in the Aegean during the summer months are blowing from the North. In this respect cave usage can be explained in two different ways: The research on monk seals in the Sporades by Kouroutos (1987) supports the second hypothesis. Further support is provided by the results obtained from cave-installed automatic cameras. A camera installed in Pip 4, during a period when the winds were blowing continuously from the North, did not record any seal in the cave, whereas cave Pip 2, with an entrance facing to the South, was used twice. The data presented above suggest that cave preference is dependent on various interrelated factors. Such conclusions, however, must be considered preliminary as they are based on a relatively limited number of visits over a short period of time. Nonetheless, it is known that both cave use and human activity in the Park vary throughout the year (MOm 1995b, MOm 1996). I would like to thank the Hellenic Society for the Study and Protection of the monk seal and especially Mr. V. Zavras for the generous organisational and financial support as well as Mrs. E. Tounta, Mr. P. Dendrinos and Mr. S. Kotomatas for their experienced guidance in the field work. Finally, I wish to express my appreciation to all the numerous persons that helped me writing my thesis and this paper. Dendrinos, P., Tounta, E., Kotomatas, S., Kottas, A. (1993): Recent data on the Mediterranean monk seal population of the North Sporades. Paper submitted to the 6th International Congress on the Zoogeography and Ecology of Greece and Adjacent Regions, Thessaloniki/Greece, April 1993. Kouroutos, V. (1987): The Mediterranean Monk Seal in the North Sporades National Marine Park, 1982-1987. Thesis for the University of Athens. Matsakis et al. (1985): Research Programme "North Sporades". Research team of Athens, Athens, December 1985. 1-30. MOm. (1990): Census and observations of the monk seal population in the National Sea Park of the North Sporades. Summer 1990. MOm. (1991): Monitoring of the Mediterranean Monk Seal population at the Northern Sporades National Marine Park 1 Nov. 1990 – 31 May 1991. Final report for Contract 6610(90)9/65 of the E.C. and the HSSPMS. MOm. (1995a): Surveillance and safeguarding of the sensitive area of the Northern Sporades. Final report for the Contract 4-3010(92)7829 between EU and Elliniki Etairia. MOm. (1995b): Continuation of the monitoring of the monk seals in the National Marine Park of the Northern Sporades. Final report for the Contract 4-3010(92)7829 between EU and Elliniki Etairia. MOm. (1996): Monk seal conservation in Greece. Part 2. Northern Sporades. A special area of conservation (National Marine Park of Alonissos North Sporades). Final report to the European Commission. Panou, A., Jacobs, J., Panos, D. (1993): The endangered Mediterranean monk seal Monachus monachus in the Ionian sea, Greece. Biological Conservation 64: 129-140. Schultze-Westrum, T. 1976. Monk Seal Investigations in Greece. Nature (8): p. 24.
Cave visits
Table 1. Cave use by seals in the study area.
Number of caves surveyed
Caves with evidence of seals
Total number of visits to caves
Number of cases with evidence
% of visits with evidence
Fig 7: Cave preference recorded during this project
Discussion
Fig. 8: Juvenile Mediterranean monk seal (Monachus monachus) in the NMPANS
Acknowledgements
References
Copyright © 2000 Alexandros Karamanlidis, The Monachus Guardian. All Rights Reserved