There is an assumption that tropical sea urchins are macroalgal grazers with the ability to control macroalgal expansion on degraded coral reefs. We surveyed abundances of Echinothrix calamaris, an urchin species common in the western Indian Ocean on 21 reefs of the inner Seychelles and predicted their density using habitat predictors in a modelling approach. Urchin densities were greatest on patch reef habitat types and declined with increasing macroalgal cover. Next, we experimentally investigated the macroalgae-urchin relationship by penning two sea urchin densities on macroalgal fields. Over six weeks, the highest density treatment (4.44 urchins m−2) cleared 13% of macroalgal cover. This moderate impact leads us to conclude that controlling macroalgal expansion is not likely to be one of the main functions of E. calamaris in the inner Seychelles given the current densities we found in our surveys (mean: 0.02 urchins m−2, maximum: 0.16 urchins m−2).

Corals from the Seychelles Islands, Indian Ocean, occur mainly as small coralline algae–vermetid remnants found in cavities adhering to the rock surface, and they rarely attain more than 2 m2 in area. Samples of Goniastrea and Porites from elevations between 1.7 and 6 m above present mean sea level were dated by TIMS 238U–234U–230Th techniques. The ages from well-preserved corals lie between 131,000 and 122,000 yr B.P., in agreement with most other observations of the last-interglacial sea level. Field evidence and dating from high marine limestones from two sections at La Digue Island indicate a period of coral buildup until 131,000 yr B.P., followed by a drop in sea level between 131,000 and 122,000 yr B.P.

Fisheries scientists and managers are increasingly engaging with fishers’ knowledge (FK) to provide novel information and improve the legitimacy of fisheries governance. Disputes between the perceptions of fishers and scientists can generate conflicts for governance, but can also be a source of new perspectives or understandings. This paper compares artisanal trap fishers’ reported current catch rates with landings data and underwater visual census (UVC). Fishers’ reports of contemporary ‘normal’ catch per day tended to be higher than recent median landings records. However, fishers’ reports of ‘normal’ catch per trap were not significantly different from the median CPUE calculated from landings data, and reports of ‘good’ and ‘poor’ catch rates were indicative of variability observed in landings data. FK, landings and UVC data all gave different perspectives of trends over a ten-year period. Fishers’ perceptions indicated greater declines than statistical models fitted to landings data, while UVC evidence for trends varied between sites and according to the fish assemblage considered. Divergence in trend perceptions may have resulted from differences in the spatial, temporal or taxonomic focus of each dataset. Fishers may have experienced and understood behavioural changes and increased fishing power, which may have obscured declines from landings data. Various psychological factors affect memory and recall, and may have affected these memory-based estimates of trends, while different assumptions underlying the analysis of both interview data and conventional scientific data could also have led to qualitatively different trend perceptions. Differing perspectives from these three data sources illustrate both the potential for ‘cognitive conflicts’ between stakeholders who do not rely on the same data sources, as well as the importance of multiple information sources to understand dynamics of fisheries. Collaborative investigation of such divergence may facilitate learning and improve fisheries governance.

The Thelotremataceae are represented on Aldabra by three species: Leucodecton compunctum, Thelotrema euphorbiae, and Thelotrema hniatukii. The latter is described here as new. It is closely related to T. euphorbiae and know so far only from Aldabra.

The lichen genus Stirtonia has been revised. Thirteen species are accepted in the genus, including three new to science, viz. S. curvata from Irian Jaya and Java, S. schummii from the Seychelles and S. neotropica from Costa Rica and the Dutch Antilles. The known range of the genus is extended from Asian to pantropical. The genus is most diverse in the palaeotropics.

We adapted a visual census method, mainly used in demersal and reef fish studies, to characterize fish communities associated to drifting fish aggregating devices (FADs) in the Western Indian Ocean. Drifting FAD associated fishes from both equatorial (Seychelles) and tropical waters (Reunion Island) were examined by divers. A total of 32 species (belonging to 16 families) were observed associated with drifting FADs in equatorial waters, and 24 species (14 families) were found around FADs in tropical waters. Twenty species were found in both regions. The highest number of species observed at a single FAD was 18 (12 ± 2, mean±SD) in equatorial and 13 (10 ± 3) in tropical waters, not counting circumnatant species loosely associated with the FAD. Some species like Kyphosus vaigiensis, Canthidermis maculata, Elagatis bipinnulata, Acanthocybium solandri and Coryphaena hippurus were observed on all or most of the surveys. In this study, the contribution in biomass of the 18 common species associated with drifting FADs (but excluding circumnatant species), represents more than 98% of the biomass. The overall biomass values of closely associated species remains well below tuna biomass estimates for circumnatant tuna schools at FADs, estimated as high as 200 tons. The species that most significantly contribute to the by-catch in tuna purse-seines logically match those that showing the highest biomass values in our surveys (Carcharhinus spp., Elagatis bipinnulata, Coryphaena hippurus, Canthidermis maculata, and Acanthocybium solandri). One of the most abundant and ubiquitous species in our study was the spotted oceanic triggerfish Canthidermis maculata that sometimes formed massive schools of many thousands individuals around the drifting FADs. Future research is needed to explore the role of such non tuna species in the attraction and aggregation processes of tuna around drifting FADs.

The only microchiropteran endemic to the granitic Seychelles, the sheath-tailed bat Coleura seychellensis, is categorized as Critically Endangered on the IUCN Red List. Using bat detectors, the islands of Mahé, Praslin and La Digue were surveyed to establish the current distribution of this species. Although two new roosts were discovered on Mahé, no bats were observed on Praslin and La Digue, and the range of C. seychellensis appears to have further contracted in the last 2 decades. A total of 19 C. seychellensis were counted emerging from or entering three roosts in boulder caves on Mahé during 18 evenings of observations. The bats foraged in open coastal habitat, some of it anthropogenic, and their echolocation calls were also characteristic of bats feeding in open habitat. This study provides no evidence that C. seychellensis is dependent on forest or wetland for foraging. Dietary analysis indicated that C. seychellensis feeds on Coleoptera, Lepidoptera and Diptera. A public education programme to highlight the conservation status of the bat and the consequences of roost disturbance is recommended, together with the urgent need for legal protection of the bats and their roosts.

The distribution of the forest tree Pisonia grandis (Nyctaginaceae) coincides with seabird colonies on small tropical islands. Its seeds are enclosed in a calyx exuding extremely sticky resin which adheres strongly to feathers. Birds are obviously seed-dispersal vectors, but the multi-seeded infructescences frequently entangle birds, often fatally. On Cousin Island, Seychelles, I investigated the production, germination, survival, and tolerance to seawater of Pisonia seeds, and the occurrence of entanglement with birds. Fresh seeds had high germination success (62–87% in experimental trays), but seedling survival in Cousin's forests was low (0.1% of 6020 seeds survived as seedlings after 2–8 mo). Some seeds tolerated 30 min daily immersions in seawater (8–15% germination after 14–28 d treatment), but not continuous immersion in seawater (reduced germination after 5 d and none after 12 d). Inter-island dispersal is likely via living unencumbered seabirds carrying a few seeds, but not on floating carcasses. Seeds attached to carcasses did not have improved germination or survival. Intra-island propagation is almost entirely vegetative, with negligible local seed dispersal. Pisonia plants therefore do not benefit from fatal entanglements. The extreme stickiness of the seeds evidently evolved to resist removal by seabirds and so facilitate long-distance dispersal. The mortality of some potential vectors is an unfortunate consequence, but has little impact on the large populations of tree- and ground-nesting seabirds which nest in or under these trees.

Tanypus complanatus sp. n., Pseudosmittia remigula sp. n, and Polypedilum (Tripodura) silhoettarium sp. n. are described as male imagines and Clunio gerlachi sp. n. as male and female imago. The male imagines of Larsia pallidissima (Kieffer), Gymnometriocnemus (Gymnometriocnemus) mahensis (Kieffer), Pseudosmittia xanthostola (Kieffer) and Polypedilum (Polypedilum) glabripenne (Kieffer) are described for the first time. The male imagines of Paramerina minima (Kieffer), Smittia megalochirus (Kieffer) n. comb., Smittia mahensis (Kieffer) and Pseudosmittia melanostola (Kieffer); and the female imago of Pseudosmittia xanthostola (Kieffer) are redescribed. A key to the known chironomids of the Seychelles is given. Twenty-eight chironomid species are known from the Seychelles, 23 from the island of Mahé, 12 from Silhouette, 3 from Curieuse, 2 from Anonyme and 1 from each of Fregate, North and the coralline Alphonse. The likely marine intertidal species appears to have their closest relatives in Micronesia and the Pacific, while the freshwater chironomid fauna appear to have more Afrotropical relatives.

Nesting hawksbill turtles Eretmochelys imbricata were studied on Cousine Island, Seychelles from 1995 to 1999. Mean overall incubation time averaged 58.1 days. Clutch size did not influence incubation periods. Following hatching, hatchlings took an average of 3.8 days to leave the nest. Mean hatchling emergence time was 60.4 days. Hatching success averaged 64.3% for the four seasons. During 1996–97 there were heavy, unexplained egg losses due to crab predation. Excluding that season, average hatching success was 70.9%. Overall hatchling success was 61.1%, translocated nests having a better success (69.3%) than natural nests (57.7%). Overall egg and hatchling losses were 35.8% and 3.1%, respectively, most egg losses being attributed to ghost crabs Ocypode cordimana (16.3% overall) and unknown causes (17.0% overall), which were mainly non-viable eggs. The high level of nest manipulation was believed to be justified by increasing the number of hatchlings entering the sea.

Nesting hawksbill turtles Eretmochelys imbricata and their eggs and young were studied on Cousine Island, Seychelles from 1995 to 1999. Numbers of females known to nest (tagged individuals) on Cousine was 146. An average of 75% of emerging adults were intercepted, and this rose to 81.6% in 1999. Mean carapace lengths and widths of adult females were 81.2×60.8 cm, and included some of the longest carapace lengths known for hawksbill turtles. There were poor correlations between adult weight and carapace length or width, but better correlations between adult weight and the product of carapace length and width. Width to length carapace proportions averaged 0.75. The mean weight of nesting females before their first recorded nesting on Cousine was 65.6 kg (51.2–83.0 kg). These were the first recorded weights for nesting hawksbills from the Seychelles. Individuals lose 8.5–15% of their body weight after laying three to five clutches. Mean clutch size was 176.7, and clutch sizes for any season showed great variation for some individuals. Clutch sizes tended to decrease after the main nesting month for the population but not necessarily for the individual. The largest clutch size of 264 is the largest recorded for hawksbill turtles worldwide. Turtles with longer carapaces tended to lay larger clutches than those with shorter carapaces, and heavier turtles generally laid heavier clutches than did lighter turtles. Eggs were usually (85.6%) somewhat elongate, measuring on average 36.3×35.5 mm, and weights averaged 25.5 g. Very few ‘pea’ eggs were found. The average hatchling weight was 14.5 g and the average carapace length and width were 39.2 and 30.1 mm, giving a mean ratio of carapace length to width of 0.77.

Illustrated descriptions are provided for four new lichen species found in The Seychelles: Arthothelium feuereri Aptroot & Seaward, Dimerella straminea Aptroot & Seaward, D. subsquamosa Aptroot & Seaward and Fellhanera silhouettae Aptroot & Seaward.

The status of the Seychelles endemic terrapins is reviewed based on field-surveys. Pelusios castanoides intergularis and P. subniger parietalis are confined to a small number of marshes and rivers. All the sites occupied are limited in area (<4.5 ha) and under threat from drainage, predation and invasion by alien water plants. The smallest populations are unlikely to be viable in the long-term. Both species can be categorized as Critically Endangered using the IUCN Red List categories, with highly restricted ranges (2.89 and 6.02 ha for P. castanoides and P. subniger, respectively) that have decreased by over 50 per cent in recent years. Conservation of these species requires both the protection of wetland habitats and the establishment of new populations in protected areas. A captive breeding programme has been established with the aim of reintroducing juveniles into secure reserves. The endemic species P. seychellensis may be extinct.

Census and other demographic data are used to estimate the volume of the illegal slave trade to Mauritius and the Seychelles from Madagascar and the East African coast between 1811 and c. 1827. The structure and dynamics of this illicit traffic, as well as governmental attempts to suppress it, are also discussed. The Mauritian and Seychellois trade is revealed to have played a greater role in shaping Anglo-Merina and Anglo-Omani relations between 1816 and the early 1820s than previously supposed. Domestic economic considerations, together with British pressure on the trade's sources of supply, contributed to its demise.

The first successful captive maintenance of living terrestrial Geonemertes nemertines is reported. Behavioural observations are described, including the first data on diet in this genus. The species G. pelaensis is found to be a predator of small molluscs. In 1907 the Seychelles population was described as a distinct species, G. arboricola, largely on the basis of its arboreal habit. Recent field data from the Seychelles islands of Mahé and Silhouette confirm the tendency towards arboreal behaviour.