Tracking leatherback turtles from the world's largest rookery: assessing threats across the South Atlantic

Despite extensive work carried out on leatherback turtles (Dermochelys coriacea) in the North Atlantic and Indo-Pacific, very little is known of the at-sea distribution of this species in the South Atlantic, where the world's largest population nests in Gabon (central Africa). This paucity of data is of marked concern given the pace of industrialization in fisheries with demonstrable marine turtle bycatch in African/Latin American waters. We tracked the movements of 25 adult female leatherback turtles obtaining a range of fundamental and applied insights, including indications for methodological advancement. Individuals could be assigned to one of three dispersal strategies, moving to (i) habitats of the equatorial Atlantic, (ii) temperate habitats off South America or (iii) temperate habitats off southern Africa. While occupying regions with high surface chlorophyll concentrations, these strategies exposed turtles to some of the world's highest levels of longline fishing effort, in addition to areas with coastal gillnet fisheries. Satellite tracking highlighted that at least 11 nations should be involved in the conservation of this species in addition to those with distant fishing fleets. The majority of tracking days were, however, spent in the high seas, where effective implementation of conservation efforts is complex to achieve.     

Diatoms in recent Atlantic (20° S to 70° N latitude) sediments: abundance patterns and what they mean

Valve abundances of marine planktonic, marine benthic and freshwater diatoms in 780 sediment surface samples from the North and Equatorial Atlantic between 20° S 75° W and 70° N 10° E display patterns that do not correspond to published records of primary production in the photic zone. On the contrary, their abundance is more closely related to dissolution and dilution by terrigenous minerogenic and biogenic carbonate material. Highest abundances of marine planktonic diatoms occur in the northern North Atlantic south of Iceland and in the equatorial regions. The central North Atlantic and the central Caribbean, which feature lower primary production in the photic zone, contain few or no diatoms in surface sediments. African derived freshwater diatoms are concentrated in a lobe between 5° S and 20° N latitude decreasing in numbers from the African continent westward.Lars Gronlien died unexpectedly in January 1992.     

Daily Cleaning Activity and Diversity of Clients of the Barber Goby, Elacatinus figaro, on Rocky Reefs in Southeastern Brazil

Gobies of the genus Elacatinus are regarded as the most specialised cleaner fishes in the western tropical Atlantic, yet there are no studies on these cleaners in the southern portion of West Atlantic. We studied the diversity of clients and the daily cleaning activity of the barber goby, Elacatinus figaro, on rocky reefs in southeastern Brazil (23–24°S). A total of 34 fish client species in 16 families were recorded over 484 cleaning events. The most frequent clients were damselfishes, Pomacentridae (37.9% of cleaning events) and grunts, Haemulidae (16.9%). Planktivores were the most frequently attended trophic category, and two species in that category accounted for about a half (44%) of the total cleaning events. Size of clients ranged 4.5–55cm and most individuals were medium-sized (12–30cm); as the barber goby ranged 2–4.5cm, clients were 1.5 to 15 times larger than the cleaner was. Cleaning activity started at dawn and ended shortly before nightfall, the highest frequency of interactions occurring at early morning (nocturnal clients) and mid-afternoon (diurnal clients). By midday the frequency of cleaning events decreased and their duration increased. A total of 109±3 cleaning events and 30±1min of cleaning activity were estimated per cleaning station per day, both figures low when compared to those recorded for cleaner fishes in tropical areas of the western Atlantic and Indo-Pacific.     

OBSERVATIONS OF FLORIDA MANATEES(TRICHECHUS MANATUS LATIROSTRIS) AROUND SELECTED POWER PLANTS IN WINTER

Sixty-four aerial surveys were flown during cold, winter weather between December 1982 and February 1772 to provide an index of trends in abundance of the Florida manatee ( Trichechus manatus latirostris )around five Florida Power & Light Company (FPL) plants. The surveys documented high winter use of warm-water discharges at four of the plants (Canaveral, Riviera. Port Everglades, and Fort Myers). The total number of manatees sighted at the five primary plants surveyed during a single survey ranged from 6 to 765 manatees (= 330 ± 45 manatees per survey): thus, up to 41% of the total Florida manatee minimum population of 1.850 animals may be found on cold days at FPL plants. The number of calves sighted at the plants during winter has decreased; similarly, for three consecutive years (winter 1989–1970 through winter 1991–1992), the percentage of the manatees that are calves sighted at the plants has decreased. Although data from the surveys of FPL plants do not necessarily reflect what may be happening with manatees located elsewhere in Florida, a possible reduction in calf numbers, coupled with increasing numbers of dead calves being documented by scientists involved in manatee carcass salvage work, is cause for concern in this slow-reproducing, endangered species.