TL: SEA TURTLE NESTING SURVEY TUNISIA 1990 SO: Greenpeace International (GP) DT: September 1990 Keywords: Greenpeace Reports Turtles Tunisia Africa North Species Oceans / Carried out for GREENPEACE MEDITERRANEAN PROJECT by research ship "Toftevaag" SURVEY ON THE STATUS OF THE LOGGERHEAD SEA TURTLE (Caretta caretta) ON THE EAST COAST OF TUNISIA August - September 1990 Table of contents Page INTRODUCTION.......................................... 1 map of region......................................... 2 1. METHOD 1.2. Beach analyses................................... 3 1.3. Track studies and night patrols.................. 3 1.4. Maritime observations............................ 4 1.5. Inquiries........................................ 4 1.6. Complementary observations....................... 41.7. Duration of survey............................... 4 2. RESULTS 2.1. Approach to beach................................ 5 2.3. Photo-pollution.................................. 52.4. Beach analyses................................... 5 a) Beach of Mahdia............................... 6 b) Beach of Thapsus island....................... 6 c) Beach of Kuriat islands....................... 6 maps and diagrams................................ 7-172.4.1. Vegetation..................................... 18 2.5. Sea turtle observations 2.5.1. Observations at sea............................18-20 2.5.2. Observations on beach..........................20-21 2.6. State of sea grass prairies...................... 212.7. Tracks........................................... 21 maps and photographs..................................22-23 2.8. Jellyfish plagues................................ 24 3. EVALUATION OF THREATS 3.1. Natural threats 3.1.1. Posidonia debris............................... 24 3.1.2. Wild dogs...................................... 253.1.3. Rats........................................... 25 3.2. Human threats 3.2.1 Disturbance.................................... 26 3.2.1.1. Campings and hotels......................... 26 press clipping....................................... 273.2.1.2. Transit..................................... 28 3.2.1.3. Lights...................................... 28 3.2.2. Debris pollution.............................. 28 3.2.3. Toxics pollution.............................. 28 3.2.4. Trade in sea turtle products.................. 293.2.5. Fisheries..................................... 29 3.2.5.1. Fishing techniques.......................... 29 a) Purse seining with lights................ 30 b) Palm leave fishing....................... 30 c) Long-lining.............................. 30 d) Trawling................................. 30 e) Octopus pots............................. 31 f) Madragues (Maze nets).................... 31 g) Fishing by hand.......................... 31 3.2.5.2. Accidental captures......................... 323.2.5.3. Directed kills.............................. 32 4. COMMENTS ON DATA FROM INQUIRIES 4.1. President of SCUBA diving federation............ 334.2. Mr. Zaiane...................................... 33 4.3. Fishermen....................................... 34 5. CONCLUSIONS....................................... 35 LIST OF PARTICIPANTS................................. 36INTRODUCTION On the basis of the results obtained by Luc Laurent's general survey of the coasts of Tunisia, Algeria and Morocco, several areas had been highlighted as interesting for further prospection. The areas concerned were mainly the region between Mahdia and the Kuriate islands on the east coast of Tunisia and several beaches { { on the south coast close to the libyan boarder. The aim of this survey was to concentrate on one of these regions by carrying out a saturation study and a complete analyses of the beach and surrounding waters in order to obtain a more precise { { picture of the status of sea turtles for the given area. By concentrating our study in this way we hoped to be able to obtain more information on the nesting trends of sea turtles on the North African coast as well as on the different threats pressurizing these populations. 1. METHOD 1.2. Beach analyses In order to carry out this survey, the research sailing ship "Toftevaag" was used as a base. This was important in order to reach several of the beaches located on islands as well as for carrying out observations out at sea of basking sea turtles. The research team consisted of 6 to 8 members of whom most were biologists (see list of participants). The research was initially planned to extend over a period of two months, from mid July to mid September [transmission error] ally shortened due to other campaign priorities and specially the lack of sea turtles encountered. The region chosen was finally the beaches between the fishing port of Mahdia and the Kuriat islands, which consist of approximately 20 Km of beach. 1.3. Track study and saturation night patrols The region was divided into several sectors which where then analyzed in detail during one day. This initial beach analyses lasted three days after which a precise map was made up for each section of beach. The aim of this initial analyses was to establish which sections were worth a saturation study with constant night patrols and which could be covered with a track study. Due to the lack of nesting signs, it was decided to cover all areas with a track study which would then evolve to night patrolling if turtles were found. The track studies were carried out by teams of two people. They were carried out daily for the beach of Mahdia and at 2 or 4 day intervals for the other beaches. 1.4. Maritime observations Maritime observations were also carried out during the trips between regions. This consisted in having two crew members keeping a constant look out for sea turtles. 1.5. Inquiries Inquiries with local people and mainly fishermen were also carried out. We tried to incite them to cooperate with the research by giving us information on any turtle they would see. This contact was mainly with fishermen established on the beach of Mahdia. 1.6. Complementary observations Several complementary observations were made, mainly on other species of animals which could interact with sea turtles. A special analyses was made of the state of sea grass prairies, as these appeared to have an important effect on the studied beaches. 1.7. Duration of survey The survey lasted for six weeks, from August to mid September. The original idea was to start in mid July in order to cover the last nestings and the hatchings of earlier nesting. 2. RESULTS 2.1 Approach to beach. Data from French sea charts (SHOM 4226 and 4227 ) were complemented with echo sounder recordings carried out for each section of beach. In general most beach parts were found to have a good approach (see maps ). Only some regions of the beaches of the three islands, had some high posidonia reefs which could become an obstacle for these sections. 2.3 Photo-pollution The intensity of fixed and moving lights was recorded for each section of beach. This was done from the ship at anchor and sailing during different times at night. The highest densities of fixed lighting were found around the villages of Mahdia and Ras Dimas, but even these were not too high. No roads go along the beaches so moving lights were restricted to those used by beach fishermen and campers (specially on the beach of Mahdia). On the islands of Kuriat and Conigliera, the only light is that of the Kuriate light house. 2.4. Beach analyses The beach was divided into the following sectors according to different parameters which were measured at the beginning of the program. The main parameters were; length, width, slope, description of surf, sand grain, type of sand, depth of sand, obstructions on beach, obstructions on sand, vegetation type, vegetation cover, humidity nv sand, temperature of sand. For each section an analyses of human activity was also added. This was divided in the following characteristics; human presence during day, human presence at night, obstructions, transit, fisheries, debris pollution, toxics pollution. a) Beach of Mahdia The beach of Mahdia was found to have a very good potential for nesting for most of its sections. However some sections on the northern part had build up posidonia debris banks of 20 to 40 cm which could become a considerable obstacle for nesting females or hatchlings. The major problem on the beach was found to be the human disturbance in the form of transit and camping. This reduced the the beach to approximately 6 usable kilometers out of 15 (see section on human disturbance). b) Beach of Thapsus island Approximately 1 km of very good beach was found in the south eastern part of the island. However this region is practically shut of by maze nets during the summer months (see fishing techniques). The other sections of beach had either a very shallow approach or in some parts the sand was mixed with large masses of posidonia debris. This posidonia debris also formed large banks at the surf (see section on sea grass prairies). c) Kuriat islands (Grande Kuriat and Conigliera) Both islands had a similar coastline. The coast could be divided in several very distinct sections. On the north western side, there was no sand beach but a limestone shelf which had been eroded forming a maze of small pools. We were told by the guard that after Northerly storms, turtles are often found washed up on this section of coast. During the prospection we found several bones and one dead turtle (see sightings on land). On the western coast and north of the Grande Kuriate island, we found large depositions ov dosidonia debris forming in some parts solid cliffs up to 1.7 meters high. On the western side of the island there is a section of very good beach (approximately 2 Km between the two islands). On the southern part of the conigliera island there is a marshy section showing signs of flooding. 2.4.1. Vegetation The vegetation on all beach sections is limited to small bushes and shrubs. The types found more common were: Bushes; (Cypressus sempervirens) (Juniperus sp.) (Opuntia ficus) Small plants; (Lillium candidum) Family of Euphorbiaceae Family of Ephedraceae Family of Cistaceae Family of Chenopodiaceae, specially (Suaeda pruinosa) 2.5 Sea turtle observations 2.5.1. Observations at sea For the following list of observations, further data as well as photographic and video material is available. IMPORTANT!!! Sizes of sea turtle carapace are approximations as observations were carried out without catching the turtles. #1 27-07-1990 1345 UT 37 38'0 N 1 35'0 E (Caretta caretta) 40 cm carapace, basking on surface. #2 7-08-1990 2030 UT 37 5'0 N 10 50'0 E (Caretta caretta) 90 cm carapace, basking on surface. #3 8-08-1990 0810 UT 36 25'0 N 11 12'0 E (Caretta caretta) 80 cm carapace, basking on surface. #4 8-08-1990 0930 UT 36 20'0 N 11 10'0 E (Caretta caretta) 70 cm carapace, basking on surface. #5 8-08-1990 0955 UT 36 18'0 N 11 10'0 E (Caretta caretta) 60 cm carapace, basking on surface. #6 8-08-1990 1020 UT 36 16'0 N 11 10'0 E (Caretta caretta) 60-70 cm carapace' basking on surface. #7 8-08-1990 1030 UT 36 14'0 N 11 10'0 E (Caretta caretta) 80cm carapace, basking on surface. #8 8-08-1990 1035 UT 36 14'0 N 11 10'0 E (Caretta caretta) ? basking on surface. #9 8-08-1990 1040 UT 36 14'0 N 11 10'0 E (Caretta caretta) 80-90cm carapace, basking on surface. #10 8-08-1990 1245 UT 36 10'0 N 11 10'0 E (Caretta caretta) 90cm carapace, basking on surface. #11 8-08-1990 1330 UT 36 6'0 N 11 10'0 E (Caretta caretta) ? basking on surface. As can be seen from the sightings map, most of these were made during the passage from Cap Bon along the eastern section of the gulf of Hammameth. The sighting conditions on the 8th of August were ideal due to the good visibility and absolutely calm sea. 2.5.2. Observations on beach #13 11-08-1990 1200 UT Beach of Mahdia (Caretta caretta) Skull and parts of carapace found on beach close to fishermen hut. Beach section B. #14 15-08-1990 1600 UT Beach of Conigliera island (Caretta caretta) Dead turtle found stranded on rocks, carapace length 87cm. These strandings are apparently common on these islands after a period of northerly gales. #15 29-08-1990 1400 UT Beach of Mahdia (Caretta caretta) Sub-adult Sea turtle (67 cm carapace) apparently (according to fishermen) caught accidentally in their net (Madrague) while coming to beach. The turtle seemed to have been kept in captivity as it had several green algae on plastron and carapace skin was decaying. The turtle was very weak. Other particularities were a missing left hind flipper and a peace of long-line coming out of cloaca (video + photo material). The turtle was tagged and released 15 miles east of the beach, Some of the fishermen were not happy as they had planned to eat it. Tag number: AW 2052 ## During the track studies many other turtle bones and carapaces were found. Also several opened egg shells wdbe found, probably from eggs laid at sea, as all findings were very dispersed. 2.6. State of sea grass prairies in the region surveyed. The Posidonia prairies in this region are abundant and at first approach seem in good condition. The most abundant species is Posidonia oceanica but Cymodocea nodosa is also common around the island of Conigliera. As described by Rodriguez Mnez, J (1982) the rhizomes of Posidonia oceanica grow both horizontally and vertically thus not only fixing the sediment but also growing up from it creating terraces of very slow growth. A great part of the islands of Thapsus, Conigliera and Kuriat seemed to have formed such terraces of Posidonia and sediment. A great part of the island seems to be build on such reefs. On all three islands also we observed solid banks of this mixed sediment reaching at parts a height of 1.5 meters. 2.7. Tracks No clear tracks of nests, nesting or hatchlings were found. On Sunday the 26th of August however, several tracks of possible emergence were surrounded by signs of struggle. The tracks had been partially camouflaged but several marks indicated that turtles had been there. This was observed in section B of the beach of Mahdia. It is difficult to know exactly the origin of the tracks. Turtles could have been brought there by fishermen for slaughtering after being caught at sea or turtles were taken during there emergence. Following this sighting a team was left on the beach to observe any future signs. Several fishermen were seen the next night walking along the beach and the next morning similar tracks were found. 2.8. Jellyfish plagues This year Tunisian tourism has been severely affected by jelly- fish plagues, specially in the region of Monastir and Hammameth. Rumors spread about the reason for this being the decrease of the sea turtle populations in the area. This rumor is spread by local environi%wtalists. 3. EVALUATION OF THREATS 3.1. NATURAL THREATS 3.1.1. Posidonia debris Posidonia debris, both in the form of dead leaves or balls appeared to constitute a serious obstacle to sea turtle nesting on these beaches. On the island of Kuriat as well as on parts of the beach of Mahdia, leaves and balls are mixed in the sand making it practically impossible to dig. On other sections, the depth of the sand was less than 15cm before a tough layer of posidonia debris was found. A common problem to the three islands but apparently new of this year for the beach of Mahdia, was the building up of debris banks along the surf. The size of these varied from day to day according to the state of the sea and tide. This also constitutes an important obstacle to nesting females or hatchlings. (The spring tides seemed to have a good cleaning effect). The cause of this great debris generation seemed natural at first sight, as no signs of mechanic destruction by trawling or other were found. 3.1.2. Wild dogs isn't the major threat to sea turtle nesting. Apart from rats no other major predator were observed. 3.1.3. Rats On the island of Conigliera a clear ecological unbalance appears to be the invasion of the island by rats. These have completely taken over from rabbits (the previous colonizer). The presence of these rats could constitute a major threat to eggs and hatchlings. 3.2. HUMAN THREATS Human activity in the region was found to be very intensive and is apparently recent but rapidly growing. It appears to be however very seasonal. The problem could be divided in the following points. 3.2.1. Disturbance The nesting season of sea turtles also coincides with the time of year when human activity is very important. Disturbance both at sea as on the beach are virtually unavoidable on the beach of Mahdia. On the three islands however the problem is restricted to daytime as these areas are left deserted at night with no lights, noise or human activity apart from on some scarce occasions. 3.2.1.1. Camping and hotels There are three hotels on the beach of Mahdia. These are situated at the southern end of the beach. The resulting threat is a great human activity in this area during the day with people, speedboats, camel and horse rides, parasols and chairs left on beach and fixed lights at night. Some hotels from Monastir also organize excursions to the Kuriate islands. Tourists are taken there by boat to spend a day on the island. Camping is a recent threat and probably reduces the chances of successful nesting to 0. During the summer months, tourists and mainly seasonal fishermen occupy the beach of Mahdia and Thapsus completely. The tents are placed close to the surf and at a very high density (one tent every ten meters). This is absolutely seasonal. As was seen during the track study, after the 15th of august the number of tents reduced drastically leaving only their garbage behind by the 25th of August. This camping trend is apparently very recent (3-4 years). 3.2.1.2. Transit Transit along the beach of Mahdia is very intense from one end to the other. It occurs in all forms; people, bikes, motorcycles, horses, camels, carts, tractors and cattle. 3.2.1.3. Lights Most lights are concentrated around the city of Mahdia and the cape of Ras Dimas. Most lights are fixed as no roads go along the beach. However campers use moving lights during there parties on the beach or during their fishing operations (see sectaoo on fisheries and lighting map.). (Moving lights could be more disturbing to nesting females than fixed lights) 3.2.2. Debris pollution Plastics are washed up on the beach and a great amount of solid waste is scattered around the camping site. This is also as recent as the camping and protests were becoming common in local press against this attitude of the "wild campers". (see press clipping) 3.2.3. Toxics pollution We have no precise data on this as it was not included in the research program, but a major environmental threat to the coast and people in this region, is a chemical industry which processes olive seeds. This international factory was apparently not allowed to establish itself in Spain and thus came here. There have been several scandals due to its effect on local population and specially workers at the chemical plant. The material obtained from the process is Furfural. It could be interesting to obtain more data on this. Workers are apparently only allowed to work here for three years before they have to leave. The plant is situated a few Km south of Mahdia. 3.2.4. Trade in sea turtle products Trade in sea turtle products is very common in the region. Sea turtle shells or stuffed turtles are sold to locals and tourists in many souvenir shops. Trade in the fish market of sea turtle products is illegal since 1989 but we observed one fisherman taking a freshly cut carapace out of the market (2nd of September 1990, 1030 UT). According to some local contacts, fishermen bypass the market frequently hiding the turtles in barrels. Apparently turtle trade in the fish market was a common scene until last year. Sea turtle meat consumption is common in this region and is well established in peoples habits. Turtle blood is also consideredPha medicine for typhoid fever and liver diseases and according to some contacts some local doctors still prescribe it to their patients. 3.2.5. Fisheries The intentional capture of sea turtles is forbidden by law since last year. However a local superstition wants it that turtles bring bad luck to fishermen, so the latter usually kill any turtle they find. Turtles are caught in different ways and apart from "accidental captures", many are caught directly when they are found basking on the surface. 3.2.5.1. Fishing techniques The port of Mahdia is the second largest fishing harbour in Tunisia. The main fleet consists of 30 to 60, 25 meter boats fishing for sardines. Trawlers are less common. A large (150-200)small boat fleet also uses different fishing techniques. The techniques used by boats are: a) Purse seining with lights which use lights to attract the fish. According to fishermen small sea turtles are often caught as they are attracted by the light. b) Palm leave fishing This is carried out by small boats which lay out several palm leaves at anchor with hooks underneath to catch fish in search of shade. It is possible that some sea turtles are caught on these hooks but this would be in reduced numbers as the extent of this fishing technique is very limited. c) Long-lining. This is carried out also by small long-lining boats leaving approximately one mile lines on the surface. According to fishermen, turtles are often caught in these long-lines. This problem is probably not comparable to the accidental captures occurring in the Balearics as long lining here is carried out by smaller boats with shorter long-lines. d) Trawling This is carried out by larger ships which go to the gulf of Hammameth or Gabes mainly. "Accidental captures" by this fishing technique has been found to be relatively important in the gulf of Gabes where an estimated 5000 - 6000 sea turtles could be caught annually. (The gulf of Gabes has great concentrations of Loggerhead sea turtles probably undergoing a form of hibernation) Accidental captures in this region by trawlers seems to reach its peak during the winter months and specially January, Febuary and March (L. Laurent 1986). However here again the only data available is from inquiries with fishermen. The fishing techniques carried out from the shore are: e) Octopus pots These ceramic pots are left in sandy regions to attract octopuses. This most probably doesn't have any effect on sea turtles apart from disturbance by human presence. _ These extend from the beaches between 500m to 2 or 3 miles. These are definitely a major obstacle for turtles approaching the beach as their chances of passing through the maze of nets is very scarce. There are two of these maze nets on the eastern part of the Kuriat island and between 5 - 6 between the island of Thapsus and the northern half of the beach of Mahdia. During stormy days with on-shore easterly winds, the section of net extending out perpendicular to the beach is folded to avoid damages. g) Fishing by hand Seasonal beach fishermen use different techniques as small lines or nets to catch fish close to the shore. Probably the more threatening one as far as sea turtles are concerned is one carried out by three men at night. Two carry petrol lamps to attract the fish, and the third uses a circular net which he throws over the fish. This activity could create an important source of disturbance. 3.2.5.2. Accidental captures It is difficult to talk about "accidental g!xtures" of sea turtles in Tunisia as fishermen are in most cases happy to catch a turtle. Even if the currant legislation has reduced the presence of turtles in the market, Turtles are still being killed eaten and traded. We have no precise data on the extent of this sea turtle harvest as this would need to be obtained from the fishermen themselves. As is explained further on, information obtained from fishermen has to be treated very cautiously. 3.2.5.3. Directed kills Apart from those turtles being caught by fishing techniques aiming at other species, several fishermen still catch sea turtles directly when these are basking at sea or nesting. We had several offers from some fishermen who wanted to provide us with turtles. During the survey we adopted since the beginning a policy of not offering anything in exchange for fisherman cooperation. This revealed to be very important as we saw later that this could have developed in a negative way for the survey and specially for the sea turtles. If these fishermen see any possibility of getting money or alcohol they immediately offer to bring as many turtles as you desire and at the same time their stories become more and more imaginative. 4. COMMENTS ON DATA FROM INQUIRIES 4.1. President of Scuba diving Federation Apart from offering the cooperation of his federation, he mentioned several other regions which he though were interesting to survey. Among these regions specially the beaches close to the Libyan boarder in the south of Tunisia. On the other hand, the local diving association of "La Marsa" (Tunis) offered to help by providing diving equipment if we wanted to document the concentrations of loggerheads in the gulf of Gabes in winter. 4.2. Mr. Zaiane Being a very well respected man in Mahdia, he wAsRone of our most valuable contacts as we could take his informations more seriously. He carried out several inquiries on our behalve amongst friends of his. Some relevant data obtained was; -The presence of turtles has decreased dramatically over the last ten years. -Directed kills are still frequent -Some kids caught an adult turtle a few days before our arrival and kept it tied up for a few days. -Sea turtle consumption has been going on for long in the region and until recently trade at the market was common. -Sea turtles are considered to bring bad luck to fishermen and are thus usually killed when met at sea. 4.3. Fishermen The value of the information obtained from the fishermen is very relative. The same fisherman would change his story from day to day, and often imagination seemed to take over the conversations. It is therefore very difficult to know what is true and what isn't from all the information we obtained from them. The following points came out more frequently; -There are sea turtles coming to nest to this region and they often catch nesting females in their nets. Apparently from 40 to 50 per year. -Turtle meat is not specially nice but when they have one they make a party supper with whiskey and turtle. -The Kuriat islands often have sea turtle nests. One old fisherman apparently knows where they have their nests. -They say turtles nest in September when the people go away from the beach. -Turtles trying to nest before September are caught in the nets or return to sea and lay their eggs in the water. Some of the beach fishermen knew very much about sea turtle nesting, others just made up stories to look as if they were helping us. 5. CONCLUSIONS From our analyses of the different beach sections, it seems clear that approximately 16 Km of this region offers ideal _ conditions for sea turtle nesting. However, the increasing pressure both at sea and on land by fishermen and tourists greatly reduces the chances of nesting and even more so the chances of successful hatching. On the other hand, the only section where human disturbance is more limited (Conigliera island) is an island infested by rats which would also leave scarce chances of survival to eggs and hatchlings. During the survey, no definite signs of nesting or hatching were observed. Sea turtles are however very common in Tunisian coastal waters, and this as well as comments from local people, would seem to indicate that sea turtle nesting was common on theses beaches until approximately ten years ago. The local fisheries are probably an important threat to both turtles at sea and nesting, although this cannot be evaluated precisely due to the difficulty of obtaining true data from fishermen. Local trade and consumption of sea turtle meat and other products is common. Wild camping invades the main beach in the region leaving no space for turtles to emerge from sea during the summer months. This form of tourism also produces a great amount of debris pollution on the beach. If governmental initiatives were adopted to control tourism and fisheries in this region, these beaches could probably offer ideal conditions for marine turtle nesting. At present, nesting females (according to beach fishermen between 40 to 50 during 1989) are probably either caught before nesting, lay their eggs at sea or move to other regions. * * * LIST OF PARTICIPANTS TO SURVEY Ricardo SagarmincGB, Skipper of research vessel "Toftevaag" [error]adas, Biologist, Universidad Autonoma de Madrid Beatriz Vidondo, Biologist, Universidad Autonoma de Madrid de Grenoble [error] ve Fernando Gonzalez-Ubeda, Biologist, Universidad Complutense de Madrid Raimundo Fernandez, Artist and seaman Bedis Zaiane, Student, Representative of Local Environmental association; Amis des Oiseaux. Essia Fathallah, Local contact