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Little is currently known about the status of turtle populations in the Eritrean Red Sea (ERS), although available evidence indicates that it is a turtle resource of global significance (Hillman & Gebremariam 1995). At the moment, green turtles (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata) are relatively common in the ERS. Eritrea's Coastal, Island and Marine Biodiversity (ECMIB) Conservation Project has proposed a turtle conservation programme (initially in the form of a local pilot project in the Fatuma Island group near the port city of Assab). This will be a nationally and regionally significant development, and will be an important addition to other proposed turtle conservation initiatives elsewhere in the Red Sea and Gulf of Aden region.

Stranding Event

In April 2003, the ECMIB Project received a report from the Ministry of Fisheries in Assab of large numbers of dead turtles stranded on islands near Assab and on beaches near some smaller coastal villages (Figure 1) in the ERS. A team of marine biologists from the ECMIB Project, Ministry of Fisheries and University of Asmara conducted a one week field trip to Assab to investigate the reports. The major objective of the field trip was to investigate the cause of death of the turtles, but also to record any evidence of turtle exploitation by fishing communities. The team contacted the local fishermen and military servicemen who made the original reports, and visited island and coastal sites where turtles were reported to have washed ashore.

Figure 1. Map of Assab and surrounding area where turtle mortalities were reported.

A total of 16 decomposing turtle carcasses were recorded during the field trip, of which 12 were identified as green turtles with curved carapace lengths (CCL) between 64 cm and 104 cm (Figure 2). Six were found on Fatuma Island near Assab, two at Bihta beach, near Beilul, and four on Rachmat peninsula, near Barasole (see Figure 1). Four other carcasses could not be identified. As all the turtles were decomposing, only carapace measurements were taken.

Figure 2. Curved Carapace Length (CCL) distribution of the green turtles (Chelonia mydas) found after the strandings near Assab.

Local fishermen reported that over 250 dead turtles were washed ashore during a one-month period from early March to early April 2003. The number of turtles stranded may represent only approximately a quarter of the actual mortalities (Murphy & Hopkins-Murphy, 1989). The actual number of turtles killed may therefore be considerably higher. As the Eritrean coastline is so sparsely inhabited, the reported strandings may represent an even smaller fraction of the total actual mortalities. Furthermore, in the absence of strong onshore winds many floating carcasses may not have been washed onto the beach (Musick pers. comm.).

Reports from the fishermen interviewed indicated that dead turtles were being carried on currents from the south, with the highest concentration of strandings occurring near Assab. The fatalities could, therefore, have occurred in Eritrean waters to the south of Assab, or in Djiboutian or Yemeni waters. The turtle carcasses found were too decomposed for necropsies to be performed, so it was not possible to establish unequivocally the cause of death although it is suspected that the mortalities are a result of fishery related activities. Although, few of the carcasses had any signs of external damage, some were missing their heads. Local anecdotes suggest that killing of turtles by crushing their heads is a common practice among trawler crews of some nationalities operating in the Gulf of Aden area, and this may have resulted in rapid loss of the head through decomposition. Dead turtles with no apparent signs of damage are quite likely to be the victims of trawling (Donnelly pers. comm.). When trawlers operate near shore, more strandings of dead turtles tend to occur, because turtles congregate when they forage near to the shore, and/or occupy near-shore waters during the nesting season.

Although hawksbill turtles are common in the area, only green turtles appear to have been affected during the stranding event. It is possible that if trawling activities were responsible for all or most of the fatalities, it may
be that hawksbill turtles were unaffected because the trawling took place close to nesting beaches or in areas where green turtles forage, particularly seagrass beds, but hawksbill turtles typically do not.

Little is known about breeding seasons and migration patterns of turtles in the ERS, although there appears to be separation of green and hawksbill nesting periods (Hillman & Gebremariam, 1995). If trawling takes place near nesting beaches during nesting season, it can result in the death of many turtles, with significant impact upon the important reproductive portion of the population. It is worthy of note that the Ministry of Fisheries in Assab recently warned trawlers in the Assab area about fishing too close to shore. There is presently little enforceable environmental legislation in Eritrea and insufficient capacity for enforcement of the existing laws. One of the roles of the ECMIB Project is to help rectify this situation.

Turtle Consumption

Evidence of turtle harvesting by local (artisanal) fishermen was also observed. The African shore of the Bab el Mandeb from northwest Somaliland to southern Eritrea is the only area of the Red Sea and Gulf of Aden where killing of live turtles is a major issue. Five green turtle carapaces were found at a fishermen's camp on Senabur Island, near Assab. The remains of at least 62 turtles were found at a fishing camp at Gahro, south of Assab. Of these, 45 could be identified, including 35 green turtles and 10 hawksbill turtles. All had been deliberately killed by the fishermen for consumption. Curved carapace length measurements on turtles that could be identified showed that some large adult green turtles were caught, while the hawksbill turtles that were caught were mostly sub-adults (Figure 3).

Figure 3. Curved Carapace Length (CCL) distribution of 40 green turtles (Chelonia mydas) and 5 hawksbill turtles (Eretmochelys imbricata) killed by local fishermen. Measurements were made on carapaces found at fishing camps, one at Senabur Island and Gahro, both near Assab.

Conclusions & Recommendations

Based on the information collected on the fieldtrip the following conclusions were reached:

1. The cause of the death of the turtles stranded during the mass mortality event could not be determined conclusively, due to the advanced state of decomposition of the carcasses.

2. The total number of turtles that perished was probably considerably higher than the number of carcasses actually found.

3. The general lack of external injuries indicates that the mass mortality was mostly likely to have been due to incidental catching by trawlers.

4. The turtles washed up came from the south, indicating that they probably died to the south of Assab in Eritrean, Djiboutian or Yemeni waters.

5. Only green turtle carcasses were found. This suggests that, if trawlers were responsible, they were operating close inshore in green turtle foraging grounds and/or near nesting beaches during the nesting season.

6. The widespread occurrence of large numbers of turtle remains at fishing villages and camps in southern Eritrea indicates that there is a need for greater awareness of sustainable management and conservation of turtle populations in Eritrea.

Accordingly the following recommendations have been made:

1. A comprehensive turtle conservation and monitoring Pilot Project is already proposed for the Fatuma Island group, as part of the ECMIB Project, Habitats and Species Conservation component. The need for such a programme is emphasised by the recent stranding event, and by evidence of turtle harvesting observed during the April field visit.

2. Prompt reporting of future turtle mass mortalities to the Ministry of Fisheries in Massawa, and the ECMIB Project, may provide an opportunity to conduct necropsies, and to determine with more certainty the cause of death.

3. Surveillance and enforcement need to be increased and strong penalties imposed to discourage trawling too close to shore where turtles are more likely to be caught.

Acknowledgements: We thank the branch head of the Ministry of Fisheries in Assab, Hassen Kerif, for reporting the turtle moralities to the ECMIB Project and for assisting the team in contacting the local fishermen and military servicemen who made the original reports, and locating sites where turtles had been washed ashore. We would like to
thank members of the CTURTLE e-mail list for helpful contributions. We are also grateful to two anonymous referees whose input improved the manuscript.

HILLMAN, J.C. & T. GEBREMARIAM. 1995. The status of marine turtle conservation in Eritrea. Resources and Environment Division. Ministry of Marine Resources, Massawa. 16 pp.

MURPHY, T.M. & S.R. HOPKINS-MURPHY. 1989. Sea turtle and shrimp fishing interactions: a summary and critique of relevant information. Center for Marine Conservation. Washington, D.C. 52 pp.