scholarly journals Abundance and size structure of a reef shark population within a marine reserve has remained stable for more than a decade

2017 ◽  
Vol 576 ◽  
pp. 1-10 ◽  
Author(s):  
ME Bond ◽  
J Valentin-Albanese ◽  
EA Babcock ◽  
D Abercrombie ◽  
NF Lamb ◽  
...  
Keyword(s):  
Size Structure ◽  
Marine Reserve ◽  
Reef Shark

Varying reef shark abundance trends inside a marine reserve: evidence of a Caribbean reef shark decline

2021 ◽  
Author(s):  
KI Flowers ◽  
EA Babcock ◽  
YP Papastamatiou ◽  
ME Bond ◽  
N Lamb ◽  
...  
Keyword(s):  
Marine Reserve ◽  
Reef Shark ◽  
Caribbean Reef ◽  
Abundance Trends

A baited underwater video system for the determination of relative density of carnivorous reef fish

2000 ◽  
Vol 51 (8) ◽  
pp. 755 ◽  
Author(s):  
Trevor J. Willis ◽  
Russell C. Babcock
Keyword(s):  
Relative Density ◽  
Size Structure ◽  
Marine Reserve ◽  
Reef Fishes ◽  
Underwater Video ◽  
Underwater Visual Census ◽  
Video Footage ◽  
Survey Techniques ◽  
Scuba Divers

Estimates of the relative density of fishes form the basis of many marine ecological studies as well as the assessment of effects of fishing or pollution. Plasticity in the behavioural response of large reef fishes to SCUBA divers means that commonly used underwater visual census (UVC) techniques do not always provide reliable estimates of relative density. The paper describes the system configuration, deployment methods, testing and use of a remotely deployed baited underwater video (BUV) system for the survey of carnivorous reef fishes (snapper, Pagrus auratus and blue cod,Parapercis colias) in marine reserves of northern New Zealand. Concurrent UVC and BUV surveys inside and outside a marine reserve showed that, whereas UVC detected few snapper in either area (resulting in little confidence in statistically significant results), BUV demonstrated significant differences in relative density. Conversely, blue cod were found to occur at significantly higher densities within the reserve by UVC, but not by BUV. The provision of accurate estimates of fish size (<20 mm error) from video footage also illustrated differences in size structure between protected and fished populations. The data suggest that a combination of survey techniques is likely to be necessary where multispecies assemblages are being assessed.

Age and size structure of Caribbean spiny lobster, Panulirus argus, in a no-take marine reserve in the Florida Keys, USA

2013 ◽  
Vol 144 ◽  
pp. 84-90 ◽  
Author(s):  
Kerry E. Maxwell ◽  
Thomas R. Matthews ◽  
Rodney D. Bertelsen ◽  
Charles D. Derby
Keyword(s):  
Size Structure ◽  
Marine Reserve ◽  
Spiny Lobster ◽  
Florida Keys ◽  
Panulirus Argus

scholarly journals Protection of large predators in a marine reserve alters size-dependent prey mortality

2017 ◽  
Vol 284 (1847) ◽  
pp. 20161936 ◽  
Author(s):  
Rebecca L. Selden ◽  
Steven D. Gaines ◽  
Scott L. Hamilton ◽  
Robert R. Warner
Keyword(s):  
Size Structure ◽  
Sea Urchins ◽  
Marine Reserves ◽  
Marine Reserve ◽  
Mortality Rates ◽  
Kelp Forests ◽  
Size Dependent ◽  
Predator Size ◽  
Top Predators ◽  
Large Predators

Where predator–prey interactions are size-dependent, reductions in predator size owing to fishing has the potential to disrupt the ecological role of top predators in marine ecosystems. In southern California kelp forests, we investigated the size-dependence of the interaction between herbivorous sea urchins and one of their predators, California sheephead ( Semicossyphus pulcher ). Empirical tests examined how differences in predator size structure between reserve and fished areas affected size-specific urchin mortality. Sites inside marine reserves had greater sheephead size and biomass, while empirical feeding trials indicated that larger sheephead were required to successfully consume urchins of increasing test diameter. Evaluations of the selectivity of sheephead for two urchin species indicated that shorter-spined purple urchins were attacked more frequently and successfully than longer-spined red urchins of the same size class, particularly at the largest test diameters. As a result of these size-specific interactions and the higher biomass of large sheephead inside reserves, urchin mortality rates were three times higher inside the reserve for both species. In addition, urchin mortality rates decreased with urchin size, and very few large urchins were successfully consumed in fished areas. The truncation of sheephead size structure that commonly occurs owing to fishing will probably result in reductions in urchin mortality, which may reduce the resilience of kelp beds to urchin barren formation. By contrast, the recovery of predator size structure in marine reserves may restore this resilience, but may be delayed until fish grow to sizes capable of consuming larger urchins.

No-take marine reserves increase abundance and biomass of reef fish on inshore fringing reefs of the Great Barrier Reef

2004 ◽  
Vol 31 (2) ◽  
pp. 149-159 ◽  
Author(s):  
D.H. WILLIAMSON ◽  
G.R. RUSS ◽  
A.M. AYLING
Keyword(s):  
Great Barrier Reef ◽  
Size Structure ◽  
Marine Reserve ◽  
Barrier Reef ◽  
Coral Trout ◽  
Quantitative Estimates ◽  
Fringing Reefs ◽  
Lutjanus Carponotatus ◽  
Average Size ◽  
Density And Biomass

The application of no-take marine reserve status to an area is expected to increase abundance and average size of individuals of species targeted by fisheries. The majority of the evidence supporting such expectations still involves comparisons of abundance at the one time of sites with and without marine reserve protection. Very few studies have data on the abundance and size structure of species targeted by fisheries in an area before reserve status is applied. Quantitative estimates of density and biomass of coral trout, Plectropomus spp., the major target of the hook and line fisheries on the Great Barrier Reef (GBR), Australia, on inshore fringing reefs of the Palm and Whitsunday Island groups, central GBR, are provided for 3–4 years before (1983–1984), and 12–13 years after (1999–2000) the establishment of no-take reserves in 1987. Quantitative estimates of density and biomass of coral trout in areas open to fishing were also collected in 1999–2000 at these two island groups. Density and biomass of coral trout increased significantly (by factors of 5.9 and 6.3 in the Palm Islands, and 4.0 and 6.2 in the Whitsunday Islands) in the reserve sites, but not the fished sites, between 1983–1984 and 1999–2000. In 1999–2000, density and biomass of coral trout and a secondary target of the fisheries, Lutjanus carponotatus, were significantly higher in the protected zones than in the fished zones at both island groups. The density and biomass of non-target fish species (Labridae, Siganidae and Chaetodontidae) did not differ significantly between reserve and fished zones at either island group. This is the most convincing data to date that the management zoning of the world's largest marine park has been effective, at least for coral trout on inshore reefs.

Structure and composition of metal particles in Pt-Sn/Al2O3 bimetallic catalysts

1990 ◽  
Vol 48 (4) ◽  
pp. 278-279
Author(s):  
A. Sachdev ◽  
J. Schwank
Keyword(s):  
Bimetallic Catalysts ◽  
Bimetallic Catalyst ◽  
Size Structure ◽  
High Surface ◽  
High Surface Area ◽  
Metal Particles ◽  
Alloy Formation ◽  
Particle Size Range ◽  
Oxide Supports ◽  
Petroleum Fractions

Platinum - tin bimetallic catalysts have been primarily utilized in the chemical industry in the catalytic reforming of petroleum fractions. In this process the naphtha feedstock is converted to hydrocarbons with higher octane numbers and high anti-knock qualities. Most of these catalysts contain small metal particles or crystallites supported on high surface area insulating oxide supports. The determination of the structure and composition of these particles is crucial to the understanding of the catalytic behavior. In a bimetallic catalyst it is important to know how the two metals are distributed within the particle size range and in what way the addition of a second metal affects the size, structure and composition of the metal particles. An added complication in the Pt-Sn system is the possibility of alloy formation between the two elements for all atomic ratios.

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