Designing Shark Sanctuaries in Belzie on the World's Second-Largest Barrier Reef
Authors in bold are staff of the Institute for Ocean Conservation Science
Chapman, D., Pikitch, E. K., Babcock, E. A., M. Shivji. 2007. Deep-diving and diel changes in vertical habitat use by Caribbean reef sharks Carcharhinus perezi. Marine Ecology Progress Series. Vol. 344: 271–275.
Abstract: Longline sampling (83 sets) supplemented with 6 pop-off archival transmitting (PAT) tag deployments were used to characterize vertical habitat use by Caribbean reef sharks Carcharhinus perezi at Glover’s Reef atoll, Belize. Longline catch-per-unit-effort (CPUE) in 2 shallow reef habitats (lagoon <18 m depth, fore-reef <40 m depth) underwent significant nocturnal increases for sharks larger than 110 cm total length (TL), but not for smaller sharks. Nocturnal CPUE of small sharks appeared to increase in the lagoon and decrease on the fore-reef, suggestive of movements to avoid larger conspecifics. PAT tag deployments (7 to 20 d) indicate that large C. perezi generally increased the amount of time they spent in the upper 40 m of the water column during the night, and inhabited much greater depths and tolerated lower temperatures than previously described. The wide vertical (0 to 356 m) and temperature range (31 to 12.4°C) documented for this top-predator reveals ecological coupling of deep and shallow reef habitats and has implications for Marine Protected Area (MPA)design.
KEY WORDS: Satellite tracking · Depth range · Coral reef ecology · Marine Protected Area · Carcharhinidae
Source: Marine Ecology Progress Series
Chapman D D F, E K Pikitch, E A Babcock. 2006. Marine Parks Need Sharks? Letter to the Editor. Science. Volume 312 Page 526. [PDF]
Chapman D D, E K Pikitch, E A Babcock, M S Shivji. 2005. Marine Reserve Design and valuation Using Automated Acoustic Telemetry:A Case Study Involving Coral Reef-associated Sharks in the Mesoamerican Caribbean. Marine Technology Society Journal. Vol 39: 42-55. [PDF]
Abstract: A non-overlapping acoustic receiver array was used to track the movements of two common shark species, nurse Ginglymostoma cirratum (n=25) and Caribbean reef Carcharhinus perezi (n=5), in and around Glover's Reef Marine Reserve (GRMR), off the coast of Belize, between May and October, 2004. Although both species exhibited partial site fidelity in that they were most likely to be detected near the area of original capture, both species also moved widely through out the 10 by 30 km atoll. One Caribbean reef shark was detected by a monitor at Lighthouse Reef, 30km from Glover's Reef across deep (>400m) open water. The mean minimum linear dispersal (MLD) was 10,5kn for Caribbean reef sharks and 7.7 km for nurse sharks, with many individuals traveling more than the 10 km width of the no-take "conservation zone" of the marine reserve. Although most sharks were tagged within the conservation zone, individuals were detected outside this part of GRMR on average 48 days out of the 150 days of observations. However, of 7 nurse sharks tagged near the center of the conservation zone, 4 were never detected outside of this part of the reserve. In general, this study suggests that effective conservation of these large roving predators requires an ecosystem-based management approach including a zoned management plan, similar to that used at GRMR, in which a fairly large no-take reserve, incorporating diverse habitats and the connections between them, is surrounded by a larger area in which fishing is regulated.
Pikitch E K, D D Chapman, E A Babcock, M S Shivji. 2005. Habitat use and demographic population structure of elasmobranchs at a Caribbean atoll (Glover's Reef, Belize). Marine Ecology Progress Series. Vol. 302: 187-197.
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Abstract: A 5 yr spring and summer survey (July 2000 to May 2004) of the elasmobranch fauna of Glover's Reef Marine Reserve, Belize, documents the use of this oceanic atoll by at least 12 elasmobranch species, including early life-stages of nurse sharks Ginglymostoma cirratum, Caribbean reef sharks Carcharhinus perezi, lemon sharks Negaprion brevirostris, and southern stingrays Dasyatis americana. Elasmobranch abundance was sampled in 3 atoll macrohabitats (deep lagoon, ocean reef, shallow lagoon) using standardized longlines. Total elasmobranch abundance did not change from year to year, but was significantly higher inside the lagoon than on the ocean reef outside the atoll. G. cirratum dominated both shallow and deep lagoon catches, with smaller individuals more prevalent in the shallow lagoon. C. perezi of all size classes dominated the ocean reef catches, but small juveniles of this species were also common in the deep lagoon. This species rarely utilized the shallow lagoon. A wide range of sizes of C. perezi and G. cirratum occupy Glover's Reef in spring and summer, with males maturing at 150 to 170 cm and 185 to 200 cm total length, respectively. The sex ratios of these species did not deviate from unity. A large juvenile Galápagos shark, C. galapagensis, was collected on the ocean reef, extending the range of this species into the Western Caribbean. Opportunistic surveys of fish markets on the Belize mainland revealed that inshore areas are utilized by early life-stages of sharks from the families Carcharhinidae (C. limbatus, N. brevirostris, Rhizoprionodon porosus) and Sphyrnidae (Sphyrna tiburo, S. lewini, S. mokarran).