Population estimates and size structure of Plectropomus leopardus (Pisces : Serranidae) in relation to no-fishing zones: mark-release-resighting and underwater visual census

2000 ◽  
Vol 51 (3) ◽  
pp. 221 ◽  
Author(s):  
D. C. Zeller ◽  
G. R. Russ
Keyword(s):  
Great Barrier Reef ◽  
Population Size ◽  
Size Structure ◽  
Barrier Reef ◽  
Visual Census ◽  
Underwater Visual Census ◽  
Coral Trout ◽  
Population Size Estimates ◽  
Lizard Island ◽  
Plectropomus Leopardus

A mark–release–resighting (MRR) technique was used to estimate population size of the coral trout, Plectropomus leopardus, on coral reefs fringing Lizard Island, Great Barrier Reef, Australia. Fish were captured by hook-and-line fishing, and marked with individual freeze-brand numbers in August 1995. An underwater visual census (UVC) technique was used during September and October 1995 both for resighting of marked fish and to make an independent estimate of fish density and thus population size. The study area was 750 966 m2 . The UVC sampled 154 000 m2 (20.5%) of this area. Six different methods of analysis of MRR gave similar population size estimates (e.g. Petersen 12 873; 95% CI 9989–15 754) extrapolated to the 4.5 million-m2 reef area from datum to 20-m depth around Lizard Island. UVC gave a population size estimate (24 182; 95% CI 21 860–26 504) twice that of MRR. The lower estimate derived from MRR may be the result of tag-induced mortality, or of the relative difficulty in discriminating between marked and unmarked trout by UVC. This is only the second estimate of population size of coral trout on an area of the Great Barrier Reef.

A new species of Stephanostomum Looss, 1899 (Digenea, Acanthocolpidae) with a bizarre oral sucker: S. adlardi sp. nov. from the common coral trout Plectropomus leopardus (Lacepède, 1802) (Perciformes, Serranidae) from Lizard Island, Great Barrier Reef

2007 ◽  
Vol 52 (3) ◽  
Author(s):  
Rodney Bray ◽  
Thomas Cribb ◽  
Andrea Waeschenbach ◽  
D. Littlewood
Keyword(s):  
New Species ◽  
Great Barrier Reef ◽  
Oral Sucker ◽  
Ribosomal Rna ◽  
Barrier Reef ◽  
Coral Trout ◽  
Lizard Island ◽  
The Common ◽  
Plectropomus Leopardus ◽  
A New Species

AbstractA new species of Acanthocolpidae, Stephanostomum adlardi is described from the serranid Plectropomus leopardus from Lizard Island in the northern Great Barrier Reef. It differs from all previously described acanthocolpids in the structure of the oral sucker which is extended into dorsal and ventral lobes each bearing a row of spines. A phylogenetic tree estimated from combined nuclear small and partial large ribosomal RNA gene sequences shows that, despite the unusual oral sucker structure, the species is a true member of the genus Stephanostomum. The molecular results also suggest that Monostephanostomum nolani is derived from within Stephanostomum.

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.

Mortality rate of a cohort of the coral trout, Plectropomus leopardus, in zones of the Great Barrier Reef Marine Park closed to fishing

1998 ◽  
Vol 49 (6) ◽  
pp. 507 ◽  
Author(s):  
Garry R. Russ ◽  
Dong C. Lou ◽  
James B. Higgs ◽  
Beatrice P. Ferreira
Keyword(s):  
Mortality Rate ◽  
Great Barrier Reef ◽  
Small Sample ◽  
Barrier Reef ◽  
Coral Trout ◽  
Marine Park ◽  
Plectropomus Leopardus ◽  
Catch Rates ◽  
Small Sample Sizes ◽  
Annual Mortality

From 1990 to 1993, samples of coral trout, Plectropomus leopardus, were collected at two coral reefs closed to fishing since 1987 in the central Great Barrier Reef (GBR). The age structure was dominated by a strong cohort which settled in early 1984 and which accounted for 54%, 45%, 42% and 36% of the experimental hook-and-line catches at Glow and Yankee reefs. Catch rates (fish person-1 hour-1) per age class per reef per year provide the first reliable estimates of the exponential rate of mortality of coral trout in zones of the GBR Marine Park closed to fishing. The annual mortality rate between the ages of 6 and 9 years was 0.115 (s.e. 0.040) at Glow reef and 0.189 (s.e. 0.100) at Yankee reef. The annual mortality rate between ages 6 and 9 years was 0.147 (s.e. 0.028) at the two reefs combined. Age-specific estimates of annual mortality ranged from 0.024 (age 7–8 at Glow) to 0.442 (age 6–7 at Yankee) but were unreliable because of small sample sizes. This is one of the first estimates of mortality rate of an exploited species in an area closed to fishing in the tropics.

Marine reserves: patterns of adult movement of the coral trout (Plectropomus leopardus (Serranidae))

1998 ◽  
Vol 55 (4) ◽  
pp. 917-924 ◽  
Author(s):  
Dirk C Zeller ◽  
Garry R Russ
Keyword(s):  
Marine Reserve ◽  
Home Ranges ◽  
Ultrasonic Telemetry ◽  
Visual Census ◽  
Underwater Visual Census ◽  
Coral Trout ◽  
Mark Release Recapture ◽  
The Mean ◽  
Plectropomus Leopardus ◽  
Catch Rates

Movements of Plectropomus leopardus (Serranidae), a major fisheries species, across marine reserve boundaries were investigated on the Great Barrier Reef, Australia. Mark-release-recapture and ultrasonic telemetry were used to assess movements. Mark-release-recapture used hook and line as the method of capture and underwater visual census (UVC) as the "recapture" tool. Catch rates were significantly higher in zones closed to fishing, despite UVC indicating no significant differences in density between closed and open zones. Of 183 fish marked with numerical freeze brands, 93 estimates of movements of branded fish were obtained. No branded fish was recorded to cross the reserve boundaries during the 2-month study, probably due to the initial decision to allocate capture effort evenly across the study area, rather than concentrating it on reserve boundaries. Fish carrying ultrasonic transmitters, and having home ranges straddling reserve boundaries, crossed boundaries on average 15.3 times ·month-1. The mean distance moved by freeze branded specimens between capture and recapture was significantly larger in areas closed to fishing than in those open to fishing. However, mean distance moved per day determined by ultrasonic telemetry did not differ between areas closed and open to fishing. This study suggests low flux rates of adult P. leopardus across marine reserve boundaries.

Effects of fishing on a protogynous hermaphrodite

2001 ◽  
Vol 58 (3) ◽  
pp. 568-578 ◽  
Author(s):  
Paul R Armsworth
Keyword(s):  
Great Barrier Reef ◽  
Population Dynamic ◽  
Dynamic Models ◽  
Barrier Reef ◽  
Coral Trout ◽  
Precise Understanding ◽  
Protogynous Hermaphrodite ◽  
Reef Fish Species ◽  
Plectropomus Leopardus ◽  
Behavioural Mechanism

Population dynamic models and simulations are analysed for a harvested reef fish species that is a monandric, protogynous hermaphrodite. The models are applied to data for the coral trout Plectropomus leopardus (Pisces: Serranidae) on the Great Barrier Reef. One model examines the situation where sexual transition is induced by some exogenous behavioural mechanism, and another considers the case where transition is determined by some endogenous developmental schedule. The conclusions regarding the effects of fishing are common to both models, and the implementation of more efficient harvesting practices may not require a precise understanding of the mechanisms governing sexual transition.

Prevalence of the parasitic cymothoid isopod Anilocra nemipteri on its fish host at Lizard Island, Great Barrier Reef

2012 ◽  
Vol 60 (5) ◽  
pp. 330 ◽  
Author(s):  
Dominique G. Roche ◽  
Laura E. Strong ◽  
Sandra A. Binning
Keyword(s):  
Great Barrier Reef ◽  
Evolutionary Ecology ◽  
Size Structure ◽  
Infected Fish ◽  
Host Population ◽  
Fish Host ◽  
Barrier Reef ◽  
Lizard Island ◽  
In The Wild ◽  
Cymothoid Isopod

Parasites are ubiquitous in nature but assessing their prevalence in wild fish populations is often challenging due to their cryptic nature. Low abundance can also hinder detailed studies. Here, we report a relatively high prevalence (4.3%; range = 0–28%) of an ectoparasitic cymothoid isopod (Anilocra nemipteri) infecting the bridled monocle bream (Scolopsis bilineatus) on reefs surrounding Lizard Island on the northern Great Barrier Reef (GBR). The prevalence of infected and previously infected fish at this location was nearly 15%, which greatly exceeds reports from other localities on the GBR. At least one parasitised fish was observed at 75% of the reefs surveyed, although prevalence varied across sites. Parasitised S. bilineatus were, on average, 25% smaller than unparasitised or previously parasitised fish. Given that these parasites have known detrimental effects on host growth, survivorship and swimming ability, our observations suggest that A. nemipteri may influence the size structure of its host population in the wild. Since A. nemipteri is large, conspicuous and relatively abundant, it provides an ideal study system to examine a range of important questions on the evolutionary ecology of parasites.

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