REPORT ON
THE 1997 GllliEN TUllTLE PROGllAM
AT TORTUGUERO, COSTA RICA
Submitted to Caribbean Conservation Corporation by
Sebastian Troeng Research Coordinator Caribbean Conservation Corporation 4424 NW 13th St. Suite A-I Gainesville, FL 32609 Ph: (352)373-6441 Fu: (352) 375-2449 Email:
" LIST OF FIGURES ACKNOWLEDGEMENTS Figure I. Seasonal distribution of green turtle nestingactivityITommile3 marker to mile 7 17 marker as determined ITomtrack surveys(n-30). The 1997 Green Tunle Program was made possible by the cumulative effons of a group of dedicated people. A grand thanks is due all those tbat contributed to making the program a Figure 2. Seasonal distribution of green tunle encounters ITom Boca del Rio Tonuguero 8 success. to mile 5 marker (n=2,416). The Ministry of Environment and Energy (EI Ministerio del Ambiente y Energia) issued the Figure 3. Spatial distribution of nesting activity ITom 5 miles nortb of Boca del Rio 9 researcb permit for tbe 1997 Green Turtle Program (Resolucion No. 137-97-0FAU). Tortuguero to 5 miles soutb of Boca del Rio Parismina as determined ITom track surveys (6 July-26 September). All data presented in this report were collected by the enthusiastic and hardworking research assistants, with support ITom program participants (Appendix I). Their long hours of work Figure 4. Spatial distribution of green turtle nests and false crawls fi'om Boca del Rio 10 and higb quality performance are gratefully acknowledged. Tortuguero to the mile 5 marker (12 track surveys, 8 July-I 8 September). Freddy Piedra Pocbel, CCC station manager, and Grethel Monge, tbe visitor centre Figure 5. megal harvest of green turtles ITom the nesting beach as determined ITom track II administradora, efficiently organized the logistics of the program in Tortuguero. The surveys (6 July-26 September): a) Boca del Rio Tortuguero to mile 5 marker, b) Mile 5 boatdriving, day and night, by Enrique Martinez and Carlos Ortega, and tbe cooking of marker to Laguna Jalov&, and c) Boca del Rio Parismina to S miles south of Boca del delicious food by Zelmira BenJys-Williams and Gloria BenJys, throughout the season, were Rio Parismina. much appreciated.
Figure 6. Spatial distribution of nesting activity ITom 5 miles north of Boca del Rio 13 The villagers ofTortuguero contributed in many ways to the program and their hospitality Tonuguero to 5 miles soutb of Boca del Rio Parismina as determined ITom track was encouraging. I would especially like to thank Thomas Alonso Rankin Gonzalez for surveys: a) 6 July-26 August, and b) 27 August-26 September. conducting the 18-mile track surveys, for solving problems and for stimulating turtle discussions. Many thanks to Carlos Olivas, the students of Tortuguero school, and the Figure 7. Ratio (RIll) between tbe proportion of green turtle encounters and tbe 14 ecological group T.A.A.F.F., for mucb fun. Their enthusiasm gives great hope for the future proportion of nesting activity (in section) p~ 1/8 mile. ofTortuguero. The tourguides ofTonuguero and tbe tourist lodges contributed with information on tagged turtles, and with criticism throughout the program. Their assistance Figure 8. Green tunle lengtb-frequency distribution (SCLmax): a) remigrants (n=23), 17 was constructive and useful. and b) recruits (n=135). Roxana Silman and Raill Gomez Gonzalez at the CCC office in San Jose, and David Godfrey Figure 9. Green tunle clutch size-ITequency distribution: a) remigrants (n=22), and b) 18 and Lucinda Taft at tbe CCC office in Gainesville provided support whenever needed. Cathi recruits (n=131). Campbell provided initial training and thorough guidance to the RC and the RAs. Cynthia Lagueux provided guidance on the finer points of the research protocol.
LIST OF TABLES The staff of Tonuguero National Park (ACTo) responded quickly to our various requests, in Table 1. Illegal harvest of green turtles from tbe nesting beach. 6 particular with regards to security on tbe beacb. The green turtle population of T ortuguero will benefit greatly ITom continued and expanded cooperation between CCC and ACTo. Table 2. Tunle encounter efficiency (%). 12 Dr. Anne Meylan and Seilora Elvira Carrillo kindly provided information on the origin of long Table 3. Within-season tag loss, first-to-Iast encounter: a) by RA present at the time of 16 distance tag recoveries. tagging, and b) by montb of tagging. Dr. Karen Bjomdai, Dr. Alan Bolten, Cynthia Lagueux and Dr. Anne Meylan provided many Table 4. Biometric data. 19 useful comments on the draft report.
Table 5. Precision of measurements. 19
iii IV I. INTRODUcnON 2.2.2 Track Surveysfrom Boca del Rio Tortugucro to Mile 5 Marker Track surveys were conducted weekly ITom Boca del Rio Tortuguero to the mile 5 marker. Green turtle (Chelollia mydas) tagging and monitoring in Tonuguero was initiated in 1955 These track surveys were always conducted by the RC, sometimes accompanied by RAs or participants. The track surveys began at Sam at Boca del Rio Tortuguero, and finished at the (CarT et 01. 1978) and has since been conducted every nesting season. The 1997 Green Turtle mile 5 marker at 8am (with the exception of29 July when the track survey did not end until Program extended from I July to 20 September. The program was organised by the Caribbean 12am due to high nesting activity the previous night). The number of nests and false crawls Conservation Corporation (CCC) and implemented by a group of research assistants (RAs) from the previous night only were recorded for each 1/8 mile section. Tracks were recorded and panicipants headed by the research coordinator (RC). The objectivesof the 1997 Green separately for each species. Evidence of illegal harvest of turtles or eggs, such as the dragmark Turtle Program were: a) to quantiJy the nesting activity along the Tortuguero nesting beach of a flipped-over turtle. dug up nests, and stick probing marks around nests, were also with emphasis on the section ITom Boca del Rio Tonuguero to the mile 5 marker, b) to recorded. quantifY biometric parameters of the nesting green turtle population such as carapace length and clutch size. c) to quantifY the level of illegal harvest of green turtles and eggs ITom the 2.2.3 Track Surveys North of Boca del Rio TortuJ:llero and South of Boca del Rio nesting beach, and d) to promote environmental awareness, in order to further local Parismino understanding of and support for, the conservation of the Tonuguero marine turtle Track surveys were conducted, a total of three times, for 5 miles of beach north of Boca del populations. Rio Tortuguero and for 5 miles of beach south of Boca del Rio Parismina. These track 2. METHODS surveys were conducted by teams of three RAs. The number ofnests and false crawls from the previous night only were recorded. Tracks were recorded separately for each species. Evidence of illegal harvest of turtles or eggs, was also recorded. 2.1 Preparations Prior to the start of the program, the positions of the mile markers from Boca del Rio 2.2.4 Seasonal Distribution of Nestillg Activity Tortuguero to the mile 5 marker were checked by RAs using a 3OO-foot fiberglass measuring Seasonal distribution of nesting activity was determined from the results of the I S-mile track tape. Missing and inaccurate markers were replaced, resulting in mile markers being surveys conducted between I March-25 October. Nesting activity was determined from green positioned every 1/8 mile. turtle nests only by excluding false crawls ITom the results.
During the first week of the program, mile markers were also placed every half mile ITom mile 5 to mile 21 4/8. 2.2.5 Spatial Distribution of Nestillg Activity Spatial distribution of nesting activity was determined by combining the results from all three types of track surveys. For each 18-mile and Boca del Rio Tortuguero to the Mile 5 Marker RAs were given training in marine turtle biology and tagging by Cathi Campbell and the RC, track survey, the number of nests were added into sections of one mile. For track surveys between 28 June-30 June. The scope and rationale of the program, as well as the RAs duties, North of Boca del Rio Tortuguero and South of Boca del Rio Parismina, the number of nests were also explained. per one mile section of beach was determined by assuming equal distribution of nesting activity along the five miles. Spatial distribution along the entire beach was determined from 2.2 Track Surveys the mean number of nests per track survey per one mile section of beach. 2.2. J J8-mile Track Surveys 2.2.6 J//egal Harvest Track surveys were conducted approximately weekly ITom Tortuguero village (mile 3 marker The extent of the illegal harvest of green turtles from the nesting beach was estimated by Bochinces) to the Jalova lagoon at mile 18. These track surveys were conducted by Me = extrapolating the results of the track surveys for the period 6 July-26 September. Thomas Alonso Rankin Gonzalez between Sam-lOam. The number ofnests and false crawls ITom the previous night only were recorded for each 1/8 mile section. Tracks were recorded 2.3 Tagging separately for each species. When illegal harvest had occurred the previous night, Me Rankin Gonzalez would determine the total number of illegally harvested turtles by counting the 2.3.I Effort dragmarks from flipped-over turtles. In case oflarge scale illegal harvest, dragmarks often Tagging of turtles from Boca del Rio Tortuguero to the mile S marker was conducted every overlapped making it difficult to determine the exact number of turtles illegally harvested. In night from I July to 20 September. The beach from Boca del Rio Tortuguero to the mile 5 such cases Me Rankin Gonzalez would estimate the number of illegally harvested turtles. marker was divided into three sections: · Boca section, extending trom the mouth of the Tortuguero river (=mile -2/8, as mile -3/8 eroded away within the tirst two weeks of the program) to mile I 3/S marker;
2 . Station section, extending from the mile I 3/8 marker to the mile 3 marker (=Bochince) in edge of the rear flippers, approximately one third of the distance from the body to tbe edge of front of the Tortuguero village; and the flipper. . Park section, extending from the mile 3 marker to the mile 5 marker. Tags were only applied by trained RAs and by two of the program participants which had Each section was covered by an early shift, 8pm-12pm, and a late shift, 12pm-4am. Each shift extensive fieldwork experience (p. Fielder and A.B. Somers). consisted of a team of a minimum of two persons, including at least one RA. The change-over between shifts took place on the beach. The Station and Park teams left the eee station The turtle's four flippers were examined for old tags, and the presence or absence of old tag (located between mile markers 2 5/8 and 2 6/8) ten minutes early so they would be on the holes and notches. Tag numbers of old and new tags were recorded in the fieldbooks, as were beach at the beginning of their shift. The Boca teams left 15 minutes early by boat and were removed, destroyed, and lost tags. The names of all RAs and program participants that dropped offby the mile-1/8 marker at the beginningof their shift.The late Boca team walked covered the shift were also recorded in the fieldbook. back to the eee station at the end of their shift. Tagging was only interrupted when lightning was very close to the tagging team, and then only until the lightning had passed. The presence or absence of fibropapillomas, and conspicuous characteristics were recorded based on a brief visual inspection. The 1/8 mile marker to the north of where the turtle was Tagging was also conducted between mile 5 and mile 21 4/8 when enough RAs and encountered was recorded, as was the beach zone in which the turtle nested, if it nested. participants were partaking in the program. During these so called "blitz" sessions, the tagging Distinction was made between three beach zones: vegetation, open and border Vegetation teams were covering their section of beach from sunset (approx. 6pm) until sunrise (approx. represents the continuous vegetation at the landward limit of the beach. The open zone is 5am). lacking any form of vegetation. The border zone is a narrow zone with scattered vegetation, located between the vegetation and open zones. Track survey data and data from the nightlytagging were used to calculatea ratio, (R,ll), between the proportion of green turtle encounters and the proportion of nesting activity (in Turtles carrying tags applied during previous years were classified as "remigrants" and turtles section) per 1/8 mile from Boca del Rio Tortuguero to the mile 5 marker. The ratio Rill = not carrying tags were classified. as "recruits". Turtles encountered more than once were (euJE.)I (nlnIN.) where elll is total green turtle encounters for a 1/8 mile section for the entire classified as "renesters" from the second sighting onwards. program period, Eo is total green turtle encounters for a beach section (Boca, Station or Park) for the entire program period, nIII is total green turtle nests determined from track surveys for 2.3.4 Tag Loss a 1/8 mile section for the entire program period, and N. is total green turtle nests determined Probability of tag loss was calculated for green turtle recruits tagged with two tags and from track surveys for a beach section (Boca, Station or Park) for the entire program period. subsequently encountered again with one or huth tags still attached. Probability of tag loss (1- Ki) was calculated by the equation l-Ki = 1-«2rdi)/(r,;+2rdi» where Ki is the probability of 2.3.2 Turtle Encol/llter Efficiellcy retaining a tag during the encounter interval i, rdi is the number of turtles encountered carrying Turtle encounter efficiency is the proportion of green turtles encountered, during nightly two tags at interval i and r.; is the number of turtles encountered carrying only one tag at tagging activities, of the total number of green turtles that emerged on the beach that night. interval i (WetheralI1982). 95% confidence limits (CL) for tag loss were calculated by the Turtle encounter efficiency is calculated separately for the Boca, Station, and Park sections. It equation 2[(K;(1- K;)(2- Kil2(r.; + rdi»t"' (WetheraIl1982). Probability of within-season tag is also calculated separately for nesting and false crawling turtles. Turtles for which nesting or loss was calculated for first-to-Iast encounter. non-nesting could not be determined were included in the false crawling category for the purpose of estimating turtle encounter efficiency. Two factors that may have affected the probability of tag loss were examined: a) the RA/RAs present, as part of the tagging team, at the time of the initial tagging, and b) month when the 2.3.3 Tag Applicatioll mId Data Collectio" turtle was initially tagged. Tags were applied after the turtle had finished oviposition or when she was returning to the sea. If the turtle was not carrying tags it was tagged with monel tags in both front flippers, 2.3.5 Biomelric Data Collectioll axillary to the first scale. Tag numbers 6980 1-75977 were used during the 1997 Green Turtle If a turtle was approached as it was beginning oviposition, the eggs were counted as they Program. dropped into the eggchamber, by a RA or participant wearing a new disposable rubber glove. Four measurements, recorded in centimetres, were taken on these turtles: The tag with the lowest tag number was applied to the right uont flipper. Turtles carrying I) eeLn-!: over-the-curve measurement uom the anterior point at the carapace midline to the only one tag were tagged with one additional tag ensuring that all turtles were carrying at least posterior tip of the supracaudals; two tags as they left the beach. Leatherbacks were tagged in the skin flap lining the trailing 2) CCLmin: over-the-curve measurement from the anterior point at the carapace midline to the posterior notch at the midline between the supracaudals;
3 4 3) SCLmax: straight line measurement !Tom the anteriormost edge of the carapace to the 3.2.3 TrackSurveys North of Boca del Rio Tortuguero alld South of Boca del Rio posterior tip of the supracaudals; Parismilla 4) SCLmin: straight line measurement ftom the anterior point at the carapace midline to the A total of three track SUlVeySwere conducted north of Boca del Rio Tortuguero and soulh of posterior notch at the midline between the supracaudals. . Boca del Rio Parismina 1T0m 17 August to 12 September.
2.3.6 Precision of Measuremellts 3.2.4 Seasonal Distribution of Nesting Activity Precision was calculated as the difference in length (cm) of two, three, four or five The main green tunle nesting season extended from late June until at least late October measurements, taken 1T0mthe same turtle during two, three, four or five encounters. (Figure I). Results 1T0mtrack sUlVeys conducted after 25 October are currently not available. The results of the IS-mile track sulVeys are consistent with the results of the nightly tagging 2.4 Dead Turtles work. Nightly green tunle encounters increased gradually 1T0mJuly to September and were Dead turtles that were encountered during any work activity were dissected in an attempt to most numerous during the last week of the program (Figure 2). determine the cause of death and to teach RAs, participants, and passing villagers and tourists about sea tunle morphology and physiology. For each dead tunle was recorded: species, date, 3.2.,5 Spatial Distribution of Nesting Activity length measurements, beach section, conspicuous characteristics and general comments. Nesting activity was high 1T0mthe mile 5 marker to the mile IS marker, with a peak between the mile 6 and mile 7 markers (Figure 3). Nesting activity was lowest in front ofTortuguero 2.5 Environmental Awareness Activities village (Figure 4). Several activities were carried out to involve local school kids in the program and to improve the relationship betWeen the local community and CCC. Regular activities included: the 3.2.6 Illegal Harvest panicipation of school children in nightly tagging activities, and providing tourguides with an Small scale illegal halVest, presumably for local consumption, occurred around both update on collected data at the information kiosk in the village. Special activities were Tonuguero and Parismina villages throughout the season (Figure 5, Appendix 5). In addition, planned for events such as Children's Day and Independence Day. large scale illegal halVest occurred within the boundaries ofTonuguero National Park. The large scale illegal halVest activity increased in late August and remained high until the end of the program. The first evidence oflarge scale illegal halVest was when 10 green tunles were 3. RESULTS found flipped-over and poachers were seen on the beach between mile markers 8 4/8 and 12, 3.1 Preparations during the 27 August "blitz" session. The increase in illegal halVest activity in late August Prior to the onset of the nightlytagging work, discussionswere held with Mr Thomas Alonso coincided with lowered wave action that allowed boats from Limon to approach the beach at Rankin Gonzalez and Cathi Campbellto determine whichmile markers were accurately night. positioned. Table I. lIIeszalhalVest of lUeen tunles !Tom the nestin beach. The old 3 4/8 marker was found to be positioned too far nonh and hence it was moved funher Beacb seetioa Time period Track Slturtlcs iIIccally Dlecally harvested . lurvcn harvested ocr ni2ht lurtles ext,aDa/aled south. It was positioned, before data collection staned, using the positions of the mile 3 3/8 8 0.88 46 and mile 35/8 markers. The mile 6 to 9 markers were positioned using the position of the mile Bocadel RioTonuguelO10Mile 6 JuI.26 Aug .---.-.-...... -....., Martel ...... -...... -...... --...... 5 marker and mile IS, 17, and 18 markers were positioned using the position of the mile 16 -i,.A.;:26.se-;;.. 4 u 46.' marker. Mile' Marter to LaI:!!!!!.!!Y.L. _ JuI..6 A!!&._ ..__... _«L__..._...... _...... __...... _...... -...... 0 27 AUR-26 SeD 5 49 1,519 3.2 Track Surveys Boca del Rio Parismina ID, Mile 6 Jul.26 Aug I 3 156 3.2.118-Mile Track Surveys ulh of Boca del Rio P.!I.!ismi!EL .--.--.-...... -....-.--...... -...-...... -....-.. 1S.5 A total of thirty 18-mile track sUlVeys were conducted from I March to 25 October 1997, Of '27A-;;i26 scP' 2 0.' All above sections NJA N/A these, II track SUlVeySwere conducted from 6 July to 26 Septe!11ber. 6 Jul.26 Scp 1,783
3.2.2 Track SlIrveys from Boca del Rio Tortllgllero to Mile ,5Marker If the results !Tom the track sUlVeys are extrapolated for the period 6 July-26 September. in A total of 12 track sUlVeySwere conducted from Boca del Rio Tonuguero to the mile 5 excess of 1,700 green tunles were illegally halVested from the nesting beach (Table I). marker from 8 July to 18 September.
5 6 Figure 1. Seasonal distribution of green turtle nesting activity from mile 3 marker to mile 17 marker as determined from track surveys (n=30).
800
700
600
;; 500 =.. .:1:: 400 ..= .. 300
200
100 I o I 11 . .. II \-Mar-97 3\-Mar-97 30-Apr-97 30-May-97 29-Jun-97 29-JuI-97 28-Aug-97 27-Sep-97 27~-97 Date
7
Figure 2. Seasonal distribution of green turtle encounters from Boca del Rio Tortuguero to mile 5 marker (n=2,416). 70
60
50
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20
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o 28-Jun 5-Jul 12-Jul 19-Jul 26-Jul 2-Aug 9-Aug 16-Aug 23-Aug 3O-Aug 6-Sep 13-Sep 2G-Sep Date
8 Figure 3. Spatial distribution of nesting activity from 5 miles north of Boca del Rio Tortuguero to 5 miles south of Boca del Rio Parismina as determined from track surveys (6 July-26 September).
9.7 10 t 11 J Track Surveys 8.3 . .. 12Track Surveys :J 7.0 .. = 6.5 11 Track Surveys .. 0 i: 6'] TIwlr\;5.9 ! = I I I I I I I 1 1 I 14.9 5 I I 1 1 I I I I 1 1 14.0 4 I . 2.2 1.7 ,) uil1.4 I o Track Surveys 0.2 0.2 0.2 0.2 0.2 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.1 0.1 0.1 0
Nonh of Boca del .. ..'"NN 0 .. ISouth of Boca del Rio Parismina Rio Tonuguero Mile
9
Figure 4. Spatial distribution of green turtle nests and false crawls from Boca del Rio Tortuguero to mile 5 marker (12 track surveys, 8 July-I8 September).
120
100
Tortuguero village 80
. False crawls 60 oNests
40
20
o '" o '" '" '" '" '" '" N '" '" '" '" '" '" '" '" '" '" N N d ... "! .,.; N N ... N ...... N ... 9 d d - N N ,.; ,.; . . . Mile
10 Figure S. OIegalharvest of green turtles from the nesting beach as determined from Comparison of track surveys conducted before and after 27 August shows the effect of the track surveys (6 July-26 September): large scale illegal harvested in T onuguero National Park. There is a drop in the relative numberof green turtle nests between milemarker 8 and 14, after 27 August (Figure 6).
3.3 Tagging a) Bocadel Rio TortU(l to mile 5 malker f 3.3.J Effort i The nightly tagging work proceeded uninterrupted for most of the Green Turtle Program. i However, on 24 July one of the RAs and a program participants were attacked on the beach I during the late Station shift. The attacker was arrested the same night thanks to the rapid E response by the permanent field station staff. Larger teams and at least one male RA or one J! male participant per team were introduced as a result of the attack. ~ I 0 The ratio Rill varied tTom Boca del Rio Tortuguero to the mile 5 marker (Figure 7). Rill o.J&.I.97 .5 97 2~97 S-Aug.97 '5-Awg-97 25-Awg-97 __97 '4-SoI>-97 2+Sop-87 110Io higher than I for 1/8 mile indicates that RAs spent more than average time in that 1/8 mile of beach. Rill lower than I for 1/8 mile indicates that RAs spent less than average time in that 1/8 mile of beach. Generally Rill is higher for the part of the sections (Boca, Station, Park) b) Mile 5 malker to Lag""" Jalova where the tagging teams began their nightly work.
J uo .00 3.3.2 Turtle EncollnterEfficiency ~ 100 I Tunle encounter efficiency was 4 to 5 times greater for nesting tunles than for false crawling 75 ~ turtles (Table 2). Turtle encounter efficiency was higher for the Boca and Station sections l than for the Park section. CI 30 I: Table 2.Turtle encounter efficien %. ~ 20 0 0 0 U I Boca Station Park Total i 0 2"Sep-97 o.J&.I.97 197 297 S-Auo-97 .5-Awg-97 25-Aug-97 __97 '''Sep-97 ! x ran e ran e x ran e )( - Nesting !46.1 17-100 53.4 22-100 34.3 IS-52 39.1 FalsecrawlsI ! 10.5 2.4-32 11l.l 4.0-38 7.1 0-14 9.2 Overall !29.5 14-75 ! 31.5 13-50 19.8 9.1-33 24.4 % c) Boca del Rio Porismina105 mile. soulb or Boca del Rio Porismi.... Ilurtles for which nCSling or non-lIC$Iing could Dolbe detennined, were included in Ibis calegol}'
3.3.3 Tag Application and Data Collection i A total of2,416 green turtle encounters were recorded from Boca del Rio Tortuguero to the l mile 5 marker during the nightly tagging work tTom I July to 20 September. Of these encounters, 1,284 were recruits, 164 were remigrants and 968 were renesters (Appendix 2). , I1> ;; I During a total of II "blitz" sessions a total of 717 green turtle encounters were recorded. Of ! 0 these 638 were recruits, 21 remigrants and 58 renesters (Appendix 3). &-U97 ,~7 25 7 S-Aug-97 ,S-Aug-97- 25-Auo.97 97 '+Sop-97 2 97 An additional 23 green turtle encounters were also recorded. These were encountered before I July, after 20 September, or outside beach seclions allocated to a tagging team. They are therefore counted separately. Of these 23 green tunles, 16 were recruits, I remigrant and 6 renesters.
II 12 ; " 010.....""'.. ..118 "010..... turtle,..11 :! ::1 0 N . CO CO g 0; 0 N . CO CO g 0; -="=0- e t> .. . ;Ii0 ;Ii0 am ..0 " ... g '1:1 i'" .. o-.. " e 008' t> _ r 9 g UI s' a:It. It. -. ;,.. oM oM ..II ::t 0 0 o cr.. I I = c.!1. 2 2 o = 3 3 "'0 . I: . o=... = . I ;;: !:I I: . .. g ;. I e J> I Co.. 1 ... .." 1 ;:: 0;.. I!. . ... c . z: c !! .. o - . - & . 3: E 10 ... III E. I' .. ..'<.- f " .. .. i' II e .. 12 I: 1 12 c I-5' 13 ;:: ; 13 ... . 5' a . i .. . UI .. .. t> r: a 11 .. 15 Co=: 1& .. II I: I: 11 '" n C .. = 18 0 18 g t> e.. ::1 II = 18 g : 01. g CI'! 01. .. 0 zo g:;I ...... at g :;I '" .. Co... Z1 g 21 g ';1 5- ..,) ::;0=o 0 n zz i! zz g ...R r ... g ...... i i... a g e !: '" '" -Co -" .. go go go go " co I!. 5- '" !;! !: n e !: ':i JI:'!! e e 0 fr e tOlfi e B.on ..g... ;::;
Figure 7. Ratio (Rill) between the proportion of green turtle encounters and the proportion of nesting activity (in section) per 1/8 mile. BOCA STATION PARK
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0.5 t o I III III o CD CD CD '" CD !.!:! !.!:! .., CD CD CD .. CD CD (:;J . co (:;J .. co (:;J ., iO (:;J !.!:!.. iO '" '" '" .., .., .., ...... Mile
14 Two green turtles originally tagged at locations other than Tortuguero were encountered overall within-season probability of tag loss from first-to-last encounter (I-K;I95%CL) of during the course of the program. Both had been caught in the sea and tagged whilst in 0.058tO.016. feeding or migratory habitats. The first was caught in the sea and tagged 23 May 1991 west of Nuevitas, north coast of Cuba (E. Carrillo pers. comm.). The second was caught in the sea Within-season tag loss varied among RAs present at the time of tagging and month of tagging and tagged 19 July 1997 at Zapatilla Cays, Bocas del Toro province, Panama (A. Meylan (Table 3). pers. comm.). Table 3. Within-season tag loss, first-to-Iast encounter: A total of 1,660 tags were destroyed at application. Of the 1,660 tags, 1,305 were recovered a) by RA present at the time of tagging and 355 tags were lost in the sand and not recovered. Destroyed tags correspond to approx. RA rdl r. l-K,f9S%CL 30% of the tags used in the program. .-R"AT 9 4 0:iS2fOj.'.9..-...... RA2 7 3 0.176tO.201 RA3 45 13 0.126tO.069 Of 1,941examined green tunles, 47 (=2.4%) had at least one fibropapilloma.However, for RA4 7 2 0.125tO.l75 26% of the green tunles with fibropapillomas, the fibropapillomas were only observed once RA5 9 2 0.lootO.t41 during multiple sightings. RA6 46 10 0.098tO.062 RA7 19 3 0.073tO.084 RA8 63 9 0.067tO.044 Of3,141 green turtles encountered, 78% were tagged after eggs were laid and 17% were RA9 17 2 0.056tO.078 RAIO 51 6 0.056tO.045 tagged as they returned to the water after a false crawl.For 5% of green turtles the nesting or RAil 46 5 0.052tO.046 non-nesting could not be determined. Of2,460 green turtles which laid eggs, 58% laid eggs in RAI2 56 6 0.05ItO.04t RAI3 10 1 0.048tO.095 the open zone, 26% in the border zone, and 16% in the vegetation zone. RAI4 51 5 0.047:tO.042 RAI5 21 2 0.045tO.064 Hawksbills (Erelmoche/ys imbricala) were encountered twelve times (corresponding to eight RAI6 54 5 0.044tO.040 RAI7 58 5 0.04ItO.037 individual females) from 7 July to 25 August. One female was encountered four times, one RAI8 12 1 0.040tO.080 female was encountered twice and the remaining six females were encountered once. The RAI9 26 2 0.037tO.052 female encountered four times had old tag notches in both front flippers. The female RA20 55 3 0.027tO.031 RA21 20 I 0.024:tO.049 encountered twice had an old tag notch in the right front flipper. The remaining six females RA22 48 2 0.020tO.029 showed no evidence of old tag holes or notches. All hawksbill encounters were located RA23 66 2 0.015tO.021 RA24 3 0 O.OootO.Ooo between Boca del Rio Tortuguero and the mile 2 6/8 marker. One of the hawksbills was RA25 10 0 O.OOOtO.OOO encountered nesting at 3:20pm in the afternoon. During 10 of the 12 encounters the RA26 17 0 O.OootO.ooo hawksbills laid eggs. Of the 10 nests, 30% were in the open zone, 500/. in the border zone and b) by month of tagging 20% in the vegetation zone. Two egg counts were conducted on nesting hawksbills (188 eggs Month rdl r. l-K;f9S%CL and 152 eggs). Measurements were taken from three females (CCln-t 88.8cm, 88.0cm, and July 142 31 0.098tO.035 78.6 em). August 219 18 0.039tO.019 September 60 3 0.024tO.028 leatherbacks were encountered five times (corresponding to five individual females) during RA-Rescarch assistanl. r.. - number of green tunles recovered with two lags al inlerval i. r. = number of the course of the program. Four of the leatherbacks were remigrants and the fifth had an old green turtles recovered with only one lag al interval i. 1-K; = probabilily of lag loss during the enCOunler tag notch in the right rear flipper. AIIleatherbacks nested in the open beach zone. interval i, 95%CL = 95% confidence limits
3.3.J Biomelric Dala Colleclioll No loggerhead (Carella carella) females were encountered on the nesting beach. Full biometric data (four measurements+egg count) were collected from 104 individual recruit 3.3.4 Tag Loss and 17remigrant green tunles (Appendix4). Partial biometric data (less than four A total of 1,942 green turtles were examined for old tag holes or notches. Of these, 19% had measurements+egg count) were collected from a considerably larger sample (Table 4). at least one old tag hole or notch in the front flipper indicating that tag loss may be substantial.
A total of 476 green tunle recruits were double tagged and subsequently encountered later in the season. Of these, 421 were still carrying two tags and 52 had lost one tag, resulting in an
15 16 Figure 8. Green turtle length-frequency distribution (SCLm8ll): Figure 9. Green turtle clutcb size-frequency distribution:
.) Nmlg,.ntll (n-23) .) remlgrants (n:022) 18 25 1. I I
20 12 f I - 10 1:. 115 .:I "I :1 I c:I10
. 5
0 : i = m i & Q 3 m S I m § ! ! 0 SCLm..(em) 60 70 80 90 100 110 120 130 1 150 160 Clutch11z8(8ggl)
b) Ncrultll (n-135) b) recruits (n=131) 18 J . I 25 12 I 20 . 10 . - . I 1:. c I .:Ii 15 0 :1 L I ------c:II 10 .
2 5 0 : Iii & Q m I I m § ! ! SCLm.. (em) 60 70 80 90 100 110 120 130 1 150 160 Clutch 11z8 (8ggl)
17 18 Table 4. Biometric data. and participants of the bird program took part in the celebration of Children's Day (Dia de los Rec:nlitJ Rem1a:rantJ All Niilos, 9 September). In addition to everybody taking part in the celebratory games, two Fulll Full+pat1iall Fulll FuIl+pat1laJl FuII+paniaJ' n x:i:S.D . x:l:S.D . X:i:S.D. X:i:S.D. x:i:S.D memorable piilatas were made in papier-machie, filled with candy and presented to the CCLmia 104 104.7:4.9 647 104..1 17 104..4 98 106.3%5.0 745 104.5%5.1 cheering school children. CCLn-t 104 105.1:4.9 633 104.7%5.0 17 104.6%5.5 96 106.7%5.1 729 104.%5.1 SCLmia 104 98.0:1:4.6 138 97.%4.5 17 97.5%5.0 24 98.0:1:4.5 162 97.%4.5 For Independence Day (Oia de la Independencia. 15 September) a large CCC banner and five SCLmu 104 98.9%4.6 136 98.%4.5 17 . 98.5:5.1 23 99.0:1:4.6 159 98.%4.5 luminaries featuring turtles were made by the RAs. Everyone working at the field station took '104-1.2'3:1:19.3 -'iJi"1i2.;;I8.9' 1:'2;;--- 1J7-4.i22"ii2.3:2£6" "'i53112.S;i94'" part in the Independence Day procession together with the village school. The banner was referring to wllcther full (i.e. eggcount+four IIIC8SIIR:meots)or paItiaI biometrics were collected from tile kept by the school as a memory of the event. tunics
On 21 September, a farewell party attended by at least 20 children was held at the field 3.3.6 Precision of Measurements station. The precision of measurements is similar for all four measurements (Table 5). Precision varies with the number of measurements collected trom the same tunle. An increase in the number of The school children also took part in the field work activities of the birdbanding program, times a turtle was measured from 2 to 5, resulted in decreased x precision of the curved measurements. following the end of the 1997 Green Turtle Program.
On eight occasions, from 25 August to 19 September, information and an update on collected Table 5. Precision of measurements. data were presented to the tourguides at the park information kiosk in the village. As the tourguides came to the kiosk to collect their tourgroup permits they were approached by RAs. I CCLmin(em) CCLn-!(em) I SCLmin(c.on SCLmax(em) I The RAs showed them the program databoards and explained the work ofCCC. This ,...MT~flo~-o.;'-o~~:Lh~'-o.; -iiiS!...t* o.; ~~!-I-:0.: ~~~. provided an informal forum for discussions between tourguides and RAs. 3! 16 1.1 0.3-2.1 115 1.0 0-2.3 II 0.7 0.7 II 0.3 0.3 4 : 4 1.2 1.I-1.3! 4 1.2 1-1.5 ! I I : I : AJ;a result of the above activities, the working relationship between tourguides and RAs 5 ! 2 1.6 1.2-2.0! 2 1.6 1.1-2.1 i i improved considerably. MTs=number of measurements collected from the individualturtle, n=green turtles, x=mean precision In addition to their busy working schedule, several RAs prepared poster presentations for the Regional Workshop in Marine Turtle Conservation in Central America which took place at 3.4 Dead Turtles John H. Phipps Biological Field Station, 26 September-I October (Appendix 7). A A total of 16 dead sea turtles were encountered during the course of the program (Appendix presentation on CCC's activities in Tortuguero was also given at the workshop (Appendix 7). 6). The majority were green turtles (n=15), and one was a dead male loggerhead. Four green turtles are thought to have been illegally harvested, four green turtles were allegedly killed by a jaguar and one green turtle is believed to have died of natural causes. The remaining six green turtles and the loggerhead were too far decomposed when found to determine the cause 4. DISCUSSION ofdeath. 4.1 Preparations 3.5 Environmental Awareness Activities To determine the positions of the mile markers with a measuring tape proved labour intensive. On 19 August, fifteen students from the ecological group T.A.A.F.F., of the Tortuguero If a GPS with a high enough accuracy could be purchased, the positions of the mile markers school, participated in the tagging work of the early shift. The response ITom the village could by determined faster and with less effort. A GPS would also provide absolute values for children to this activity was very positive. From then until the end of the program. one or two the positions of mile markers instead of relative values (i.e. distance from another marker). children would accompany the early shifts, providing at least one RA in the team spoke This would guarantee less variation in mile marker positions between programs and years. Spanish. Both the RAs and the village children found this to be an enjoyable and educational experience. . Very few turtles were encountered during the initial training of the RAs. If the training ofRAs is conducted at the mid-beach section (mile 6 marker to mile 15 marker) where nesting The teacher Carlos Olivas at the village school is very supportive of cooperative activities and activity is higher (Figure 3), they would get more tagging experience before starting the actual coordinated participation of the children in the nightly work. As a result all CCC staff, RAs, data collection.
19 20 4.2Track Surveys . efficient as data yielded per unit effort would be maximised. This assumes that the logistics of transporting and maintaining personnel and equipment on this part of the beach could be For population monitoring and modelling purposes, track survey data may prove more useful satisfactorily resolved. However, data has historically been collected mainly ffom Boca del than nightly tagging data. If that is the case, it is desirable to switch the emphasis of the Green Rio Tortuguero to the mile 5 marker. Changing the focus of program activities to another Turtle Program ffom nightly tagging to track surveys. However, nightly tagging activities section of beach would therefore make comparison with previous years' data difficult. deter illegal harvest to a greater extent then do track surveys. 4.2. 6/llegal harvest 4.2.1 18-Mile Track Surveys The results of the track surveys clearly show that illegal harvest is a major issue affecting the The IS-mile track surveys started at the village ("'IIIile 3 marker) for a large part of the 1997 Tortuguero green turtle population (Figure 5, Table I). Illegal harvest for local consumption Green Turtle Program. This renders comparison with historic track survey data difficult. is small in comparison to the large scale illegal harvest occurring along the mid-beach section, Therefore IS-mile track surveys should always be conducted &om Boca del Rio Tortuguero away ffom human settlements (Figure 5). to Boca del Rio Parismina (and be called 22-mile track surveys). This requires that transport across Laguna lalova is arranged for the track surveyor. During the beginning of the nesting season the sea is generally too rough for boats to approach the beach. By September, however, wave action has decreased sufficiently to allow Observer variation in track surveys may be substantial. Important sources of observer boats ffom Lim6n to land on the beach at night. This is when a large number of turtles are variation are the cues a track surveyor use to distinguish between nests and false crawls. To being taken ffom the nesting beach, a majority of which is transported to Lim6n for slaughter maintain consistency, track surveys should always be conducted by the same person. It is and sale. desirable that the track surveyor occasionally is accompanied by a potential successor in order to ensure smooth succession of track surveyors and to quantifY observer variation. The extrapolated estimate of the total number of green turtles illegally harvested from the nesting beach in Tortuguero should be considered conservative. The estimate does not include 4.2.2 Track Surveys from Boca del RIo Tortuguero to Mile 5 Marker turtles taken ffom below the high tide line as their tracks would have been washed out before If track surveys are conducted weekly ffom Boca del Rio Tortuguero to Boca del Rio the track surveys. Neither does the estimate include turtles illegally harvested before 6 July or Parismina then weekly track surveys from Boca del Rio Tortuguero to the mile 5 marker is a after 20 September when illegal harvest is known to occur (Appendix 5). duplication of effort.
Comparison of track survey data collected before and after 27 August shows a decrease in 4.2.3 Track Surveys North of Boca del RIo Tortugl/ero and South of Boca del Rio Parismina nesting activity between the mile S marker and the mile 13 marker, after 27 August (Figure 6). This corresponds to the section of beach where illegal harvest is most prevalent (pers. obs., Nesting activity was low north of Boca del Rio Tortuguero and south of Boca del Rio T.A. Rankin GonzAlez pers. comm.). Parismina (Figure 3). However, the track surveys south of Boca del Rio Parisrnina are useful for the purpose of quantifying illegal harvest of turtles and eggs from the nesting beach Anecdotal information indicates that the large scale illegal harvest from Tortuguero National (Figure 5). Park became a serious problem around 1992. If this is the case, then the spatial distribution of nesting activity along the entire beach may have been affected. This can be tested by 4.2.4 Seasonal Distribution of Nesting Activity comparison of spatial distribution data before and after early September, for years previous to Considerable green turtle nesting activity occurred after 20 September (Figure I). If the entire and after 1992. green turtle nesting season is to be covered, then program activities will have to be extended at least until the end of October. However, several individuals familiar with the seasonal Stricter enforcement of the legislation protecting nesting turtles within the Tortuguero distribution of green turtle nesting activity in Tortuguero consider the 1997 green turtle National Park is needed to reduce illegal harvest. This will require additional funds for nesting season to have been atypically late (A. Carr, C. Lagueux, A. Meylan, T.A. Rankin extensive beach patrols by Tortuguero Conservation Area (ACTo) staff. Reactivation and all GonzAlez pers.comm.). All year track surveys from Boca del Rio Tortuguero to Boca del Rio season manning of the ranger station close to the mile II 4/8 marker would almost certainly Parismina for several years would provide the necessary data to quantifY the seasonal variation deter illegal harvest along the mid-beach section. in nesting activity among years. Anecdotal information and observations from track surveys indicate that illegal harvest of 4.2.5 Spatial Distribution of Nesting Activity eggs may be considerable (Appendix 5, pers. obs.). Weekly track surveys are not sufficient to Green turtle nesting activity is high between the mile 6 marker and the mile IS marker (Figure quantifY the illegal harvest of eggs. Nests will have to be marked and followed until hatching, 3). Hence, program activities focusing along the mid-beach section would be most cost- in order to adequately estimate the illegal harvest of eggs.
21 22 4.3 Tagging Several data parameters are affected by the variation in ability and experience among persons 4.3. I Effort collecting the data. For example; fibropapillomas were observed only once during multiple The safety of RAs and program participants has to be appropriately addressed. It would be sightings for 26% of turtles with fibropapillomas. Also, abnonnal growths and tumours which desirable for CCC to acquire communication equipment that allows persoMel on the beach to were not fibropapillomas may have been misidentified as being fibropapillomas. contact park staff or the field station if need be. At least one male person on each team makes RAs and program participants more comfortable with the nightly tagging work. The collection of data on the beach zone in which turtles nest is another parameter of questionable value. The definition of the zones leaves room for subjective judgements which The tagging teams always started at the same end ofthe sections (Boca, Station, Park). This may affect the quality of collected data. The quality of the zone data is further compromised resulted in uneven coverage as less time was spent towards the end of the sections (Figure 7). by the fact that tagging persoMel are more likely to miss a turtle nesting in the vegetation This is most apparent for the Boca and Park sections. The Station section had a lower level of zone than a turtle nesting in the open zone. nesting activity than the other two sections and subsequently coverage was more even (Figure 7). . It is possible that a few hawksbills were misidentified as being small 1;1een turtles (Figure 8). Considering the small size overlap of nesting hawksbills and green turtles, misidentification Shorter sections and more teams from Boca del Rio Tortuguero to the mile 5 marker would could only have been possible for a very small number of turtles «5). RAs were trained to result in more complete coverage of the beach. One team per one mile section would ensure distinguish between species using visual cues such as overlapping scutes and number of high turtle encounter efficiency (Figure 7). However, a shift in focus towards a variety of prefrontal scales. None of the hawksbills encountered more than once were ever identified as a monitoring activities rather than towards higher turtle encounter efficiency, may be more green turtle. Therefore misidentification is unlikely to have occurred. desirable. 4.3.4 Tag Loss 4.3.2 Turtle Encounter Efficiency The probability of tag loss varied among RAs present as part of the tagging team (Table 3). Turtle encounter efficiency is affected by several factors, the most important being visibility, As RAs became more experienced, the probability of tag loss decreased considerably from RA experience and effort. Heavy rain, high tide and no moon, make it difficult to find turtles 0.098~.035 in July to 0.03~.019 in August and 0.024~.028 in September (Table 3). The and turtle tracks. Under those conditions turtle encounter efficiency will be low. Experienced reduction in the probability of tag loss from July to September is the result of discarding old RAs can predict how long a nesting turtle will spend on the beach before it returns to the sea. tag applicators and RAs becoming more experienced in dealing with turtles and better at Hence, experienced RAs will achieve high turtle encounter efficiency as they spend little time identifYing incorrectly closed tags. This emphasises the importance of training personnel waiting for turtles to finish nesting. The tagging effort per unit beach will also affect turtle extensively before tagging begins (Bjorndal et 01. 1996). A longer training program, preferably encounter efficiency. The length of the three beach sections (Boca, Station, and Park) differs. conducted at the mid-beach section where nesting activity is highest, is advisable (Figure 3). The Park section is the longest, extending for two miles. Subsequently, turtle encounter Limiting the number of persoMel actually tagging turtles is another approach that will limit efficiency for this section was lower than for the other two sections (Table 2). tag loss.
Another factor affecting turtle encounter efficiency is the track survey results. If tracks are Tag loss in green turtles has been shown to be greater for monel tags than for titanium tags missed because they have been removed by high tide or rain, turtle encounter efficiency will be (Limpus 1992). Tagging is an integral part of the Green Turtle Program. Considering the size overestimated. If tracks from nights other than the previous night are interpreted as fTesh ofCCC's financial commitment to the Green Turtle Program, it would be advisable to invest tracks, turtle encounter efficiency will be underestimated. in titanium or inconel tags with simple closing mechanisms, as this would only slightly increase the total cost of the program. 4.3.3 Tag Application and Data Collection The very high percentage (approx. 30%) of tags destroyed at application was caused by a 4.3.5 Biometric Data Collectioll combination offactors. First, the design of the closing mechanism - a bubble with a pin which The analysis and discussion ofbiometric data are more interesting in the context of previous the sharp end of the tag has to bend around - is complicated and results in many destroyed years' biometric data. Unfortunately such a discussion is outside the scope of this report. tags (L. Ogren pers. comm.). Second, several of the tag applicators used during previous seasons and may have been worn and/or not compatible with the batch of monel tags used The collection of a single curved measurement is logistically simple. Hence, a curved length during the 1997 Green Turtle Program (G. Balazs pers.comm). Discarding tag applicators at measurement could be taken from each encountered turtle. However, the standard the end of each season may reduce the number of tags destroyed at application (G. Balazs, P. measurement for the green turtle monitoring in Tortuguero is SCLmax (Carr 1980). The Ross pers. comm.). conversion ofSCLmax measurements to e.g. CCLmin has to be ensured if the standard
23 24 measurement for Tortuguero is to be changed ftom SCLmax to CCLmin. In order to accurately convert SCLmax to CCLmin, careful collection of both measurements over one or 5. REFERENCES more seasons will be necessary (K. Bjorndal, A. Bolten pers.comm.). Bjorndal, K.A., Bolten, A.B., Lagueux, C.J. and A. Chaves (1996). Probability of tag loss in 4.3.6 Precision of Measurements green turtles nesting at Tortuguero, Costa Rica. 1. Herpetol.. 30(4),567-571. The precision of the measurements appears to be similar for all four measurements (Table 5). However, the sample size is too small to exactly determine the precision of straight carapace Carr, A (1980). Some problems of sea turtle ecology. Amer. Zoo., 20, 489-498. measurements. More multiple straight length measurements will have to be collected if a comparison of precision between curved and straight measurements is to be made. Carr, A, Carr, M.H., and AB. Meylan (1978). The ecology and migrations of sea turtles, 7. the West Caribbean green turtle colony. Bull. Amer. Mus. Nat. Hist.. 162(1), 1-46. 4.4 Dead Turtles The information collected on dead turtles support the results from the track surveys i.e. illegal Limpus, C.1. (1992). Estimation of tag loss in marine turtle research. Wildl. Res., 19,457- harvest is considerable. However, very few of the illegally harvested turtles were found on the 469. beach as a majority of them was transported away from Tortuguero National Park for slaughter and sale. Nevertheless, data on dead turtles may provide useful information Wetherall, I.A. (1982). Analysis of double-tagging experiments. Fish. BII/I., 80, 687-701. regarding trends in natural and human induced mortality. It is therefore suggested that such information is collected coming seasons. A protocol for what information to collect ftom dead turtles should be developed in order to standardise data collection.
4.5 Environmental Awareness Activities Toftuguero is a village that has experienced rapid development and human population increase in recent years. This is mainly a result of increased tourism in the area. These sudden changes have had several effects on the community. The standard of living and consumption of outside goods have increased. Villagersnow livein larger housesand are wealthierthan only a few years ago. All changes, however, have not been positive. The young people ofTortuguero are now exposed to a variety of threats such as drugs, illegal harvest and theft. The long history of presence in the area gives CCC an opportunity to counteract such negative influences. Involvement of the local community, both children and adults, in the activities ofCCC is of paramount importance. The long term survival of the Tortuguero marine turtle populations can only be guaranteed if the people living in Tortuguero take an active role in the protection of turtles. The experience of the three months of cooperation between the village school, tourguides, park staff and CCC, has been encouraging. Momentum for further cooperation and protection oftunles has been created. This momentum should be utilised and the CCC Turtle Programs of 1998 will play an imponant role in the further development of successful conservation in the Tortuguero area.
25 26 6. RECOMMENDATIONS ~ Careful examination of a sample of green turtles would result in an adequate estimate of
fibropapilloma incidents. 6.1 Preparations ~ When technologically and financially possible, CCC should acquire a GPS to establish ~ Only one carapace length measurement should be taken, fTom all encountered turtles.
pennanent positions for mile markers. ~ Comparison ofiength-fTequency distribution of a) green turtles nesting from Boca del Rio
~ Training ofRAs should be extensive and located at the mid-beach section (mile 6 marker to Tortuguero to the mile 5 marker, and b ) green turtles nesting from the mile 8 marker to mile IS marker). the mile 14 marker. may reveal if last years' illegal harvest have seriously affected the
~ Theft fTom the statio. ccurred throughout the season. Lockers and doorlocks should be population.
installed at the field station to alleviate this problem.
~ An agreement by which Tortuguero Conservation Area (ACTo) staffwith assistance trom 6.4 Dead Turtles
CCC maintain a presence at the ranger station by the mile II 4/8 marker would reduce ~. A protocol for what information to collect from dead turtles should be developed. illegal harvest. 6.5 Environmental Awareness Activities
6.1 Track Surveys ~ Environmental education programs targeting both young and adult inhabitants of
~ Track surveys should be conducted weekly from Boca del Rio Tortuguero to Boca del Rio Tortuguero should be developed and implemented as part of the Green Turtle Program.
Parismina all year round. The track surveys should always be conducted by the same track Local participation in CCC activities should be promoted. surveyor.
6.3 Tagging
~ The green turtle program should be extended at least until the end of October to cover the
entire green turtle nesting season (Figure I).
~ The security of tagging personnel on the beach is inadequate. Each tagging team should be
given communication equipment allowing them to contact the ACTO office and the field station if needed. An attempt should be made to recruit at least 50% male RAs and
participants. ~ Reducing the effort put into tagging nesting females would allow time to conduct a wide variety of monitoring activities.
~ Titanium or inconel tags with an easily inspected closing mechanism should be used instead
of the currently used monel tags.
27 28 Susan Glessner 27 July 9 August APPENDIX1: Research Assistants and Participants. Liz Gordon 20 July I August Carol Han 10July 12 July Research Assistants Hilburn Hillstadt 10 July 12July From Until Eileen Hiney 3 August 5 August Lena BOljesson 10 August 20 September Arthur Jecza1a 27 July 9 August Nathaniel W. Carroll 1July 20 September Meagan Johns 6 July II July Leia Castaileda 7 July 20 September Jeremy Koshel 23 August 28 August Robert Clark 1 July 20 September Katherine Kutis 61uly 17 July Belinda Dick 1July 20 September Elizabeth Lee (UNCG) 19 July I August Laura de Entrambasaguas 10 August 20 September James "Mac" McElroy 3 August IS August Laura Estep 1 July 23 August Amy Monnett (UNCG) 191uly I August Jorge Gamboa ISJuly 1 August Jennifer Murrow (UNCG) 19 July 1 August Janneke van Gerwen 1July 20 September Amelia Nash 10 July 12July Holly Gittlein 15 July 20 September Ram Papish 2 August 20 September Elizabeth Glynn 1July 20 September Maljorie Putman 12July 17July Gijs-Jan van Hoorn I July 20 September John Rosegrant 3 August 15 August Diana Lawhorn 15 August 20 September Jean Schumann 31 August 5 September Grethel Monge I August 3 September AM Sommers (UNCG) 19July I August Kristen Nelson 1 July 20 September AMe Taylor 31 August 5 September Carlos Onega 1 July I August David Tingler 3 September 20 September Thomas Alonzo Rankin Gonz8les 19 August 20 August Randy Weiss 10 August 16 August Miguel Rodriguez Ramirez 1July 14 July Linda Whisnant 12July 17 July Claire Shirley 1 July 9 September Erika Woods (UNCG) 19 July I August Ryan Sincic 1 July 20 September Frank Yeatman 3 August 5 August Sergio Vargas Gomez 1 July 14 July Carmel Zetts 121uly 17July Taylor White 15 August 20 September Manin Zanarian I July 20 September UNCG =University ofNonh Carolina at Greensboro Participants From Until Ann Arnold-Krieg 7 September 12 September Donna Bender 3 August 15 August Melissa Bilo 27 July 9 August Katherine Bosak 7 September 12 September David Cromwell 10 August 22 August Deborah Crouse 27 1uly 1August Julie Davies 20 August 21 August Stephanie Dole 10 August 16 August Brian O'DoMell 2 August 15 September Katherine Drury 20 August 21 August Paul Fielder 27 July 9 August Alexandra Flood (UNCG) 19 July 1 August Matthew Freeborn 17 August 30 August Charlotte Glessner 27 July 9 August
A-I A-2 9-Aug 23 455 1 69 11 152 35 676 APPENDIX 2: Green turtles encountered from Boca del Rfo Tortuguero 10-Aug 23 478 1 70 15 167 39 715 to Mile 5 Marker from 1 July to 20 September 1997. 11-Aug 21 499 1 71 17 184 39 754 Remlgrants Renesters Total 12-Aug 22 521 4 75 17 201 43 797 Recruits 13-Aug 21 542 1 76 11 212 33 830 10 552 5 81 5 217 20 850 Date Daily Cumulative Daily Cumulative Daily Cumulative Daily Cumulative 14-Aug 1-Jul 6 6 0 0 0 0 6 6 15-Aug 9 561 2 83 5 222 16 866 2-Jul 9 15 2 2 0 0 11 17 16-Aug 17 578 1 84 7 229 25 891 3-Jul 3 18 0 2 0 0 3 20 17-Aug 10 588 4 88 6 235 20 911 4-Jul 4 22 1 3 0 0 5 25 18-Aug 12 600 7 95 14 249 33 944 5-Jul 10 32 0 3 1 1 11 36 19-Aug 27 627 2 97 25 274 54 998 6-Jul 3 35 1 4 0 1 4 40 20-Aug 16 643 5 102 25 299 46 1044 7-Jul 2 37 0 4 0 1 2 42 21-Aug 8 651 2 104 12 311 22 1066 8-Jul 1 38 0 4 0 1 1 43 22-Aug 25 676 1 105 23 334 49 1115 9-Jul 6 44 2 6 0 1 8 51 23-Aug 23 699 3 108 28 362 54 1169 10-Jul 4 48 0 6 0 1 4 55 24-Aug 20 719 1 109 17 379 38 1207 11-Jul 1 49 1 7 0 1 2 57 25-Aug 9 728 1 110 13 392 23 1230 12-Jul 10 59 0 7 0 1 10 67 26-Aug 11 739 2 112 8 400 21 1251 13-Jul 15 74 0 7 2 3 17 84 27-Aug 17 756 6 118 17 417 40 1291 14-Jul 14 88 3 10 1 4 18 102 28-Aug 13 769 3 121 17 434 33 1324 15-Jul 10 98 1 11 5 9 16 118 29-Aug 18 787 1 122 14 448 33 1357 16-Jul 15 113 1 12 3 12 19 137 30-Aug 15 802 2 124 15 463 32 1389 17-Jul 9 122 1 13 2 14 12 149 31.Aug 24 826 2 126 32 495 58 1447 18-Jul 16 138 3 16 4 18 23 172 1-Sep 40 866 1 127 19 514 60 1507 19-Jul 10 148 3 19 2 20 15 187 2-Sep 20 886 0 127 15 529 35 1542 20-Jul 15 163 4 23 2 22 21 208 3-Sep 20 906 0 127 16 545 36 1578 21-Jul 8 171 3 26 0 22 11 219 4-Sep 20 926 5 132 19 564 44 1622 22-Jul 5 176 1 27 2 24 8 227 5-Sep 21 947 1 133 11 575 33 1655 23-Jul 14 190 2 29 2 26 18 245 6-Sep 16 963 0 133 24 599 40 1695 24-Jul 14 204 1 30 4 30 19 264 7-Sep 22 985 5 138 27 626 54 1749 25-Jul 20 224 2 32 5 35 27 291 8-Sep 15 1000 3 141 23 649 41 1790 26-Jul 35 259 4 36 7 42 46 337 9-Sep 16 1016 0 141 15 664 31 1821 27-Jul 16 275 3 39 9 51 28 365 10-Sep 10 1026 0 141 13 677 23 1844 28-Jul 34 309 3 42 6 57 43 408 11-Sep 25 1051 3 144 32 709 60 1904 29-Jul 8 317 1 43 8 65 17 425 12-Sep 18 1069 4 148 15 724 37 1941 30-Jul 14 331 3 46 13 78 30 455 13-Sep 19 1088 0 148 32 756 51 1992 31-Jul 12 343 5 51 7 85 24 479 14-Sep 22 1110 2 150 32 788 56 2048 1-Aug 18 361 6 57 10 95 34 513 15-Sep 25 1135 6 156 29 817 60 2108 1171 1 157 27 844 64 2-Aug 14 375 1 58 8 103 23 536 16-Sep 36 2172 3-Aug 10 385 2 60 3 106 15 551 17-Sep 29 1200 3 160 33 877 65 2237 61 4-Aug 10 395 0 60 1 107 11 562 18-Sep 29 1229 1 161 31 908 2298 5-Aug 6 401 2 62 7 114 15 577 19-5ep 24 1253 3 164 29 937 56 2354 31 1284 0 164 31 968 2416 6-Aug 6 407 1 63 5 119 12 589 20-Sep 62 7-Aug 10 417 1 64 14 133 25 614 TOTAL 1284 164 968 2416 8-Aug 15 432 4 68 8 141 27 641
A-3 A-4 APPENDIX 3: "Blitz" sessions. 20 September 15to 5 21 0 4 25 E 20 September 15to 5 31 0 7 38 F Green Turtles Leatherbacks 20 September 15to 5 28 0 2 30 G H Date Mile Comments 20 September 15to 5 34 0 2 36 Ret.....its Remlgrants Renesters TOTAL Remlgrants I 20 TOTAL 114 0 15 129 21 July 9to 14 13 1 0 14 A September 21 July 1410 18 10 0 1 11 B 21 July TOTAL 23 1 1 25 TOTAL 638 21 58 717 '1 22 July 51011 9 3 1 13 22 July 91014 15 0 1 16 A. Startedal 9pm. 22 JUly 1410 18 16 0 1 17 B. Slarted al 11pm. 22 July 1111022 0 0 0 0 1 C. Teamretumedal 10pmdue10illnessof tagger. 22 July TOTAL 40 3 3 46 1 D. Team encounleredpoachelSandspenl majority of nighl,flippingturtles backover. E. Startedal 5pm. 31 July 5108 7 1 0 8 F. Startedat6pm. 31 July 81011 23 2 4 211 G. Startedat 6:45pm. 31 July 111014 22 0 1 23 H. Startedal 7:30pm. 31 July 14to 18 15 0 3 18 I. Turtleencounterefficiency(%) .. 12.7%(basedon Mr RankinGonzj\/ez'stracksurvey tor 21 September). 31 July TOTAL 67 3 8 78
4 August 5to 10 16 1 2 19 4 August 1010 14 11 0 1 12 4 August 14to 18 23 0 3 26 4 August TOTAL 50 1 6 57
7 August 51010 21 1 2 24 7 August 1010 14 33 0 1 34 7 August 1410 18 111 3 1 23 7 August TOTAL 73 4 4 81
14 August 51010 3 0 3 6 C 14August 10to 14 21 0 2 23 14August 1410 18 25 0 1 26 14 August TOTAL 49 0 6 55
111August 51010 24 2 3 29 111August 10to 14 76 1 1 78 19August 14to 18 24 1 1 26 19 August TOTAL 124 4 5 133
27 August 5to 9 14 0 1 15 27 August 91014 17 1 0 18 D 27 August 14to 18 18 1 3 20 27 August TOTAL 47 2 4 53
31 August 5t084/8 16 2 4 22 31 August TOTAL 16 2 4 22
3 Seplember 15105 35 1 2 38 3 September TOTAL 35 1 2 38
A-S A-6 50 71331 108 97.1 97.4 104.5 104.5 I-Aug-97 51 71421 103 102.6 103.2 108.0 108.6 30-Aug-97 APPENDIX 4. Blometrlc data. 52 71527 116 102.2 102.6 108.0 108.7 2-Aug-97 Date Remark. Recruit. lowe.t Egg. SCLmln SCLmax CCLmln CCln" 53 71543 133 98.2 98.4 104.7 105.1 2.Aug-97 tag. (em! (em! (em! (em! 54 71612 154 108.0 108.7 114.9 114.9 16-Aug-97 1 69824 101 90.5 92.0 98.2 98.6 2-Jul-97 55 71615 96 101.7 103.1 108.5 108.5 14-Sep-97 101.9 103.2 15-Jul-97 2 69826 115 96.8 98.9 56 71626 109 93.9 95.1 99.8 100.0 6-Aug-97 3 69834 129 106.6 107.1 113.5 113.7 19-5ep-97 57 71718 151 104.9 105.1 110.7 110.7 10-Sap-97 4 69841 120 96.6 96.8 103.9 103.9 5-Jul-97 58 71726 150 104.7 106.1 112.2 113.7 I-Aug-97 5 69845 82 96.3 97.1 101.8 102.8 5-Jul-97 59 71737 118 104.6 105.6 109.0 109.4 17-Aug-97 2-Jul-97 6 69652 98 99.1 102.3 108.1 108.2 60 71751 102 98.5 98.9 106.7 107.3 9-Aug-97 7 69669 95 101.6 102.7 109.9 110.2 3-Jul-97 61 71757 147 95.5 96.5 100.6 100.9 9-Aug-97 112.9 5-Ju1-97 6 69914 99 104.3 104.6 112.5 62 71775 122 96.7 97.2 101.8 102.0 9-Aug-97 9 69921 129 100.0 100.4 109.0 109.3 7-Jul-97 63 71797 102 92.5 93.5 99.6 99.8 8-Sap-97 10 69981 112 96.3 99.4 102.7 103.0 9-Ju1-97 64 72034 110 105.2 106.1 111.9 112.1 8-Aug-97 110.4 9-Jul-97 11 69984 96 100.4 100.6 109.2 65 72047 108 92.7 93.2 98.9 99.1 3-Sep-97 12 70000 98 91.2 91.3 103.3 103.9 11-Jut-97 66 72177 109 97.7 98.7 104.1 104.5 12-Aug-97 13 70003 127 99.4 102.2 104.1 104.7 6-Aug-97 67 72222 134 102.1 102.7 108.5 108.7 I-Sep-97 12-Jul-97 14 70067 110 103.8 104.4 111.3 111.8 68 72273 137 104.0 104.6 111.0 111.0 28-Aug-97 15 70070 131 97.8 99.0 104.5 104.5 12-Jul-97 69 72472 147 101.4 101.6 109.3 109.8 17-Aug-97 16 70127 113 93.5 94.2 98.7 99.3 16-Aug-97 70 72542 110 102.3 102.7 107.2 107.6 15-Aug-97 17 70132 122 105.5 105.9 112.5 112.6 16-JuI-97 71 72563 108 93.8 94.0 99.2 99.3 10-Sep-97 16 70146 147 97.6 96.0 103.0 103.6 31-Aug-97 72 72565 114 90.2 91.2 98.2 99.0 17-Aug-97 19 70165 98 101.4 102.7 107.5 108.0 19-Aug-97 73 72739 144 99.3 100.0 105.1 105.3 3-Sep-97 20 70176 97 95.5 95.6 101.7 101.7 14-Jul-97 74 72763 126 98.7 99.4 105.6 106.7 18-Aug-97 102.9 18-Jul-97 21 70234 142 97.6 98.2 103.1 75 72768 145 103.7 104.7 110.1 110.4 18-Sep.97 18-Jul-97 22 70243 120 93.7 95.4 99.8 100.0 76 72813 96 96.0 96.5 102.1 102.2 31-Aug-97 23 70248 110 98.4 100.1 105.8 106.3 9-Aug-97 77 72832 92 88.0 88.9 93.5 94.2 20-Aug-97 19-Jul-97 24 70250 84 93.1 93.2 100.2 100.7 78 72848 133 97.9 98.6 104.9 105.2 20-Aug-97 104.7 105.4 3D-Jul-97 25 70265 99 98.2 98.8 79 72943 100 96.2 97.4 102.2 102.2 22-Aug-97 19-Jul.97 26 70360 79 97.8 99.9 103.9 104.7 80 73251 108 98.2 99.5 103.0 103.5 21.Aug-97 2D-Jul-97 27 70363 123 98.2 100.0 106.3 106.8 81 73264 84 97.8 98.5 103.9 104.2 22-Aug.97 97.2 28 70386 85 91.0 91.2 97.0 25-Aug-97 82 73341 98 98.5 99.5 105.5 105.6 26-Aug-97 29 70388 86 97.7 97.9 103.2 103_3 14-Aug-97 83 73351 116 99.9 101.0 104.8 104.9 16-Sep-97 30 70402 129 91.6 92.5 96.5 98.7 23-Aug-97 84 73373 104 95.5 96.0 101.5 101.9 24.Aug-97 31 70417 107 98.5 99.4 105.3 105.4 11-Aug-97 85 73720 160 100.2 101.2 107.6 107.6 28-Aug-97 110.9 20-Jul-97 32 70429 123 103.1 103.7 110.9 86 73776 89 89.8 91.2 94.9 95.2 31-Aug-97 33 70443 135 95.9 96.6 102.0 102.4 22-Jul-97 87 73798 90 93.0 93.9 99.5 99.7 2-Sep.97 23-Jul-97 34 70446 130 98.8 99.7 106.5 106.7 88 74041 88 97.5 97.6 104.7 104.8 4.Sep.97 35 70468 106 99.1 99.3 105.2 105.5 3Q-Aug-97 89 74043 146 106.5 106.7 113.4 113.7 4.Sep-97 36 70462 75 92.6 93.3 98.3 99.5 23-Jul-97 90 74078 116 93.6 93.9 101.0 101.3 3-Sep-97 37 70498 117 97.5 97.9 102.8 103.1 25-Jul-97 91 74160 97 96.7 98.2 103.9 104.3 5.Sep-97 .Hawksbill? 38 70549 123 97.1 97.8 102.6 103.1 26-Jul-97 92 74184 83 83.0 84.1 88.0 88.2 5-Sep.97 39 70644 115 97.0 98.2 104.5 104.8 20-Aug-97 93 74194 86 99.2 100.1 105.5 106.5 5-Sap-97 40 70843 94 88.9 90.2 97.0 97.8 5-Aug-97 94 74225 126 102.1 103.2 109.0 109.2 6-Sap.97 41 71012 115 91.1 92.4 98.6 98.8 28-Jul-97 95 74359 96 99.6 100.8 107.9 108.5 6-Sap-97 42 71066 116 98.5 102.1 104.3 106.0 3D-Jul-97 96 74414 115 106.2 106.7 114.0 114.0 8-Sep-97 43 71107 73 98.5 99.0 103.6 103.6 14-Sep.97 97 74435 97 98.8 99.6 107.9 108.5 7-Sap-97 44 71136 96 92.9 94.6 101.0 101.2 27-Jul-97 98 74455 116 99.0 101.3 107.0 107.7 8.Sap-97 45 71217 110 99.6 101.2 105.8 106.0 23.Aug-97 99 74477 118 101.8 102.3 108.5 108.5 9.Sep-97 46 71271 113 93.6 94.9 99.3 100.3 3-Aug-97 100 74520 118 102.2 103.1 110.4 111.0 1'-Sap-97 47 71278 97 98.1 98.4 104.5 104.5 3-Aug-97 101 74808 90 99.2 99.5 106.4 107.0 13-Sap-97 48 71282 123 104.4 104.6 113.9 114.9 4-Aug-97 102 75049 140 99.1 100.4 104.9 105.3 18-Sap-97 49 71318 110 95.4 96.4 100.9 101.5 3-Sep-97 103 75223 100 89.4 90.4 97.5 98.3 19-5ap-97
A-8 A-7 104 75240 122 103.8 105.6 110.5 111.6 17-Sep-97 104 MEAN 112.3 98.0 98.9 104.7 105.1 S.D 19.3 4.6 4.6 4.9 4.9
Remigrants 1 35123 68 102.9 104.4 110.0 110.5 2Q-Jul-97 2 35929 118 94.4 94.6 102.2 102.5 l-Aug-97 .first of two biometrics from same turtle 3 52764 114 98.2 99.1 105.9 107.6 10-Aug-97 4 55020 94 97.6 99.2 104.3 104.7 13-Aug-97 5 55200 140 100.5 100.8 105.0 105.2 7-Sep-97 6 56804 128 95.6 96.5 102.0 102.0 14-Aug-97 7 59454 96 92.3 93.9 98.4 98.9 27-Aug-97 8 59481 106 99.2 100.3 106.5 107.4 12-Aug-97 9 59567 105 92.9 93.4 98.9 99.4 6-Sap-97 10 59646 113 108.6 109.7 115.9 116.3 9-Jul-97 11 59894 68 90.7 92.4 97.2 97.4 31-Aug-97 12 62161 98 92.4 92.7 97.3 97.7 4-Jul-97 "firstoftwobiometrics from same turtle 13 62197 118 92.6 92.8 99.0 99.5 ll-Jul-97 14 62636 139 98.9 99.4 103.8 104.0 17-Aug-97 15 62920 162 106.2 106.7 113.4 113.9 7-Aug.97 16 64560 127 97.6 98.0 104.3 104.5 9-Sep-97 17 64794 136 96.7 101.0 106.6 107.4 10-Aug-97 17 MEAN 113.5 97.5 98.5 104.2 104.6 S.D 24.8 5.0 5.1 5.4 5.5 GRAND TOTAL 121 MEAN 112.5 98.0 98.9 104.6 105.0 S.D 20.0 4.6 4.6 5.0 5.0
A-9 APPENDIX 5. Notes and anecdotal Informationon Illegalharvest 27 August: 10 turtles flipped back and rescued from poachers at Mile 9 to Mile II 'I,. Three poachers seen at Mile 8 'I.. Observed and reported illegal harvest. 29 August: Approximately 100 turtles taken at Mile 8 to Mile 9 'I. (observed during morning 28 June: Remains of green turtle found 30 m north of Mile 3/8 marker. Tracks of green turtle track survey). At least 3 turtles poached by Mile 4 2/. (poachers were using the taken uom in uont of CCC station. hidden path starting behind the Mile 4 2/. marker). 3 July: Early shift (S-12pm) at the Boca encountered possible poachers. 30 August: Two nests poached by Mile I 3/.. Attempted poaching of nest by Mile 3 and Mile 4 July: Turtle track covered up by mile 2 5/S. 3 2/.. 7 July: Nest with marks from someone using a stick to look for eggs by mile 2 liS. 6 September:Turtle poached by Mile 3 II.. Approximately30 turtles poached inthe park. II July: Nest poached by three men during the day by mile 2 5/8. Nest poached at Mile 3 3/.. Stick used to look for eggs at Mile 3 II, and 33/,. 12 July: Two possible poachers encountered at Boca late at night (claimed to be looking for 7 September: Turtle poached by Mile -'I.. their tent, not people uom the village). 12 September: Turtles poached by Mile I 3/. and by Mile 3 2/.. Stick used to poke for eggs at 14 July: Green turtle taken by mile I liS (up-track but fake down-track). Mile 2 'I.. Nest poached by Mile 2 'I.. 16 July: Turtle poached by villager. 13 September: Four suspected poachers ~uestioned by parkguards at the bo,.. 17 July: Three teenagers using a stick to probe for eggs during the day. IS September: Turtle poached by Mile 2 I. and by Mile 4. 22 July: Turtle poached? Uptrack without downtrack at Mile -'/.. 5 October: Staff at Mawamba Lodge flipped back eight turtles between CCC station and the 25 July: Eggpoaching in uont of village (reported by two French tourists). airport. 27 July: Nest poached at boc&, remains of a fire with glowing embers. S October: Young poacher arrested outside CCC station with a sack of turtle meat and eggs. 29 July: Turtles poached at Mile I and Mile I )/. (Laguna Lodge path), uptrack without Two more turtles poached by Mile I II.. downtrack and where turtle had been dragged along the ground clearly visible. Two nests poached in uont ofvillage (one from the night before), attempts made to find Anecdotal information regarding illegal harvest. another two nests using a stick to probe for the nests. Turtle flipped over by Illegal harvest of turtles for consumption in Tortuguero is generally higher in the beginning of guardpost at Mile 3 3/., rescued by late park shift. Poached turtle at boca? Uptrack the season when people have not eaten turtle meat since last season. Illegal harvest in the park without downtrack. increases in late August or early September when the sea is calm enough for boats from 2 August: Possible poachers at the boca. Fire behind the beach. Limon to approach the beach at night. 7 August: Poached turtle close to CCC station. Uptrack without downtrack. At least six nests poached between Mile 14 'I. and IS. Illegal harvest of eggs occurs along the entire beach. Occasionally people come from the 10 August: Family on the beach looking for eggs using a stick. banana plantations to Tortuguero to buy turtle eggs. The price is approx. 75-100 colones/egg. 11 August: Three turtles poached in uont of the village (uptracks without downtracks), one of Turtle meat is sold in the village by poachers. The majority of turtles poached around them rescued by national park staff. Attempted poaching of nest using a stick in Tortuguero village, however, are being shipped to Limon for slaughter and sale. front of the village. 14 August: Boat with three men at Mile IS at Sam, most likely poachers. Illegal harvest of eggs and turtles around Parismina village is extensive. Very few eggs are left 16 August: Five men using a stick to look for eggs just north of the CCC station. to develop and hatch. 17 August: Stick used to look for eggs at Mile _1/., 2 '/., 3 2/.. 20 August: Turtle poached by poachers hideout at Mile 4 1/.. Dead turtle found washed up at Limon is the major market for the large scale illegal harvest occuring in T ortuguero National Mile I '/.. Cracked carapace and ropes attached to both uont flippers. Park. 21 August: Turtle poached by Mile 11/. (uptrack without downtrack). Dead turtle found washed up at Mile 2 '/.. Anterior part of carapace cracked. 23 August: Turtle flipped over at the beach by Laguna Lodge, rescued by CCC volunteer. Turtle with cracked carapace on the beach trying to nest. Released by poachers before they got caught by national park staft'! 24 August: Stick used to look for eggs at Mile 33/.. Turtle flipped over and hid in the vegetation by Mile 33/,. rescued by CCC staff in the morning. Turtle flipped over by Mile 2, rescued by late station shift (three men seen on the beach, must have been the poachers). 26 August: Turtles poached by Mile I II. and Mile O.
A-IO A-II . ------..~
APPENDIX 6: Dead turtles. Number Date Species Sex Mile CCLmin CCLn-t SCLmin SCLmax 1 14-Ju1-97 Loggerhead M 33/8 101.4 102.7 94.9 99.0 2 23-Ju1-97 Green ? 165/8 3 1-Aug-97 Green F 61/8 102.7 103.0 4 1-Aug-97 Green F 54/8 99.2 99.5 5 14-Aug-97 Green F 151/8 104.7 104.8 6 19-Aug-97 Green F 152/8 104.5 105.6 7 19-Aug-97 Green F 152/8 102.8 103.4 8 19-Aug-97 Green F 152/8 101.6 101.7 9 19-Aug-97 Green M? 14 8/8 95.7 96.0 10 20-Aug-97 Green F 16/8 103.3 103.5 11 21-Aug-97 Green ? 27/8 94.3 95.7 12 23-Aug-97 Green F? 1 1/8 106.0 107.0 13 20-Se~97 Green F? 14 4/8 99.6 99.8 14 25-Se~97 Green M 5/8 89.7 90.2 15 4-Od-97 Green F 94/8 16 9-0d-97 Green F 24/8 104.8 105.2 Number Comments 1 Washed up on the beach. Head, flippers and tail missing. 2 Washed up on the beach. Head, flippers and tail missing. Too decomposed to determine sex. 3 Eyes still intad when found. Body cavity intad but surprisingly empty, only approx. 20 eggs inside. 8 vertebral scutes. Natural death? 4 Plastron and inside missing. Illegally harvested? 5 Presumably killed by jaguar with two cubs (spotted by Mr Rankin Gonz6Iez). 6 Presumably killed by jaguar with two cubs (spotted by Mr Rankin Gonz6Iez). 7 Presumably killed by jaguar with two cubs (spotted by Mr Rankin Gonz6Iez). 8 Presumably killed by jaguar with two cubs (spotted by Mr Rankin Gonz6Iez). 9 Washed up on the beach. 10 Washed up on the beach. Rope aUached to flippers. Harpoon hole in carapace. Anterior part of carapace cracked. 11 All appendages missing. Anterior part of carapace cracked. 12 Washed up on the beach. 13 Washed up on the beach. Only carapace remaining. 14 Washed up on the beach. Head and right flipper missing. 15 Eyes still intad. Hidden in the vegetation behind the beach. Forgotten by poachers? 18 Poacher arrested for butchering the turtle.
A-12
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