Population dynamics and stock management of the black-lip pearl oyster, Pinctada margaritifera (L.), in the Cook Islands, South Pacific

1992 ◽  
Vol 43 (6) ◽  
pp. 1423 ◽  
Author(s):  
NA Sims
Keyword(s):  
Growth Parameters ◽  
Total Mortality ◽  
Pearl Oyster ◽  
Minimum Size ◽  
Stock Management ◽  
Shell Size ◽  
Pinctada Margaritifera ◽  
Cook Islands ◽  
Size Limits ◽  
One Year

Permanent transects were used to measure changes in abundance of Pinctada margaritifera in Manihiki lagoon, Cook Islands. Growth in situ, mortality and recruitment were also studied. A correction factor for searcher efficiency was also determined, allowing earlier estimates of standing stocks to be adjusted. Overall abundance in Manihiki decreased by 18% in one year. Most losses were attributable to fishing (F=0.19; M=0.11). Mortality (27%) and recruitment (9%) were presumably underestimated because of heavy fishing of juveniles. Total mortality, estimated by Wetherall plots, decreased from 0.48 to 0.35 over the year owing to a decline in fishing for larger oysters. The average shell diameter of recruits was 110 mm. This was also an approximation of Ic,. von Bertalanffy growth parameters of K=0.26 and L∞ = 183 mm were estimated from shell size increments. Yield-per-recruit calculations indicate that minimum size limits are not effective. Reserve areas, quotas, and other restrictions on effort should instead be used to protect broodstocks.

Abundance and distribution of the black-lip pearl oyster, Pinctada margaritifera (L.), in the Cook Islands, South Pacific

1992 ◽  
Vol 43 (6) ◽  
pp. 1409 ◽  
Author(s):  
NA Sims
Keyword(s):  
Distribution Patterns ◽  
Pearl Oyster ◽  
Shell Size ◽  
Pinctada Margaritifera ◽  
Cook Islands ◽  
The North ◽  
Pearl Oysters ◽  
Depth Gradients ◽  
Abundance And Distribution ◽  
Ongoing Monitoring

Stocks of Pinctada margaritifera were surveyed in three atoll lagoons in the Cook Islands to assess abundance, describe distribution patterns, and evaluate the method for ongoing monitoring. Belt transects were laid at randomly selected sites across the lagoons. Densities over depth gradients were extrapolated to give a stock estimate for Manihiki lagoon of 2.0 million�3.2 million pearl oysters. Stocks in Penrhyn lagoon (5.0 million � 4.1 million) and Suwarrow lagoon (around 400 000) were estimated from average densities. The wide confidence limits mean that other methods are needed to monitor changes in abundance over time. Penrhyn and Suwarrow lagoons have not recovered from earlier overfishing. No pearl oysters occurred below 36 m. Density and shell size increased with depth; this was most notable in Manihiki, where fishing was heaviest. Sizes and densities were influenced by bottom type in Manihiki. Density was greatest in the north of Penrhyn and decreased southwards; Manihiki had no density gradient across the lagoon.

scholarly journals Ecología poblacional de Cittarium pica (Gastropoda: Trochide) en la isla de San Andrés, Reserva Internacional de Biósfera, Seaflower.

2017 ◽  
Vol 65 (4) ◽  
pp. 1496 ◽  
Author(s):  
Jeimmy Paola Rico Mora ◽  
José Ernesto Mancera Pineda ◽  
Luis Alberto Guerra Vargas
Keyword(s):  
Size Structure ◽  
Growth Parameters ◽  
Total Mortality ◽  
Minimum Size ◽  
Fishery Resource ◽  
Management Actions ◽  
Exploitation Rate ◽  
The Caribbean ◽  
San Andres ◽  
Cittarium Pica

Cittarium pica is a conspicuous gastropod of the rocky coastlines of the Caribbean. Given its importance in the diet of Caribbean communities, it has been over-exploited, even reaching extinction in some places, and the species has been included in the red lists of marine invertebrates in some countries. Its fishery in San Andres Island-Colombia is artisanal without any regulation, leading to a decrease in its population. Taking into account the socio-economic, cultural and ecological importance of C. pica and its vulnerability to extinction, it is urgent to develop management actions directed to increase the resilience of the species and its sustainability as a fishery resource. To assess the current population state of C. pica from San Andrés Island, we estimated size structure, sex structure, maturation size, and growth parameters, based on length-frequency data analysis. From September to December 2013, and January to March 2014, we randomly collected 458 individuals at eight representative sites of the rocky shores of the island. We measured the longest diameter of the shell base, determined the sex by the color of the gonad, and thus determined the minimum maturation size. We found, that 80 % of the population consisted of small individuals < 25.5 mm sizes. The sex ratio was 1:1 except in November, where males were more abundant. The minimum size at the beginning of maturity for both sexes was 14.07 mm. The growth parameters of von Bertalanffy: K (0.730 yr-1), L∞ (110.78 mm) and Φ (3.95) were higher when compared to other populations of the Caribbean. The total mortality was 3.39 yr-1, while natural and fishing mortalities were 1.02 yr-1 and 2.36 yr-1, respectively. The maximum annual recruitment pulse was estimated for June, and the maximum exploitation rate for a sustainable yield was between 0.563 and 0.640, when the catch size was greater than 40 mm or 50 mm, respectively. The exploitation rate was estimated in 0.70, suggesting a strong extractive resource pressure. With these results we recommend the closure of the fishery and constant monitoring to promote and the population recovery is verified. Until a monitoring shows that the population recovers on the island.Until a monitoring shows that the population recovers on the island.

Impact of the period of the day on mortality and major cardiovascular complications after vascular surgeries

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
F.A.M Cardozo ◽  
T Artioli ◽  
B Caramelli ◽  
D Calderaro ◽  
P.C Yu ◽  
...  
Keyword(s):  
Multivariable Analysis ◽  
Total Mortality ◽  
Mortality Rates ◽  
Cardiovascular Complications ◽  
Cardiac Complications ◽  
Funding Source ◽  
Confounding Variables ◽  
Significant Difference ◽  
One Year ◽  
Night Period

Abstract Introduction Patients submitted to arterial vascular surgeries are at a high risk of postoperative cardiac and non-cardiac complications, therefore developing strategies to lower perioperative complications is essential to optimize outcomes for this subgroup. Recent studies have suggested that the period of the day in which surgeries are performed may influence postoperative major cardiovascular complications but there is still no evidence of this association in vascular surgeries. Purpose Our goal is to evaluate whether the period of the day in which surgeries are performed may influence mortality and cardiovascular outcomes in patients undergoing non-cardiac vascular procedures. Methods Patients who underwent non-cardiac vascular surgeries between 2012 and 2018 were prospectively included at our cohort. For this analysis, subjects were categorized into two groups: those who underwent surgery in the morning (7am - 12am) and those who underwent surgery in the afternoon/night (12:01pm - 6:59am). The primary endpoints were to compare the incidence of major adverse cardiac events (MACE - acute myocardial infarction, acute heart failure, arrhythmias, and cardiovascular death) and total mortality between morning and afternoon/night surgeries within 30 days and one year. The secondary endpoint was the incidence of perioperative myocardial injury (PMI) in both groups. PMI was defined as an absolute elevation of high-sensitivity cardiac troponin T (hs-cTnT) concentrations ≥14ng/L. Multivariable analysis using Cox proportional regression (with Hazard Ratio – HR and Confidence Interval – 95% CI) was performed to adjust for confounding variables, including emergency and urgent surgeries. Results Of 1267 patients included, 1002 (79.1%) underwent vascular surgery in the morning and 265 (20.9%) in the afternoon/night. After adjusting for confounding variables, the incidence of MACE at 30 days was higher among those who underwent surgery in the afternoon/night period (37.4% vs 20.4% – HR 1.43, 95% CI: 1.10–1.85; p=0.008). Mortality rates were also elevated in the afternoon/night group (21.5% vs 9.9%, HR 1.59, 95% CI: 1.10–2.29; p=0.013). After one-year of follow-up the worst outcomes persisted in patients operated in the afternoon/night: higher incidence of MACE (37.7% vs 21.2%, HR 1.37, 95% CI: 1.06–1.78; p=0.017) and mortality (35.8% vs 17.6%, HR 1.72, 95% CI 1.31–2.27; p&lt;0.001). There was no significant difference in the incidence of PMI between groups (p=0.8). Conclusions In this group of patients, being operated in the afternoon/night period was independently associated with increased mortality rates and incidence of MACE. Mortality and MACE at one year Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): FAPESP - Fundação de Amparo a Pesquisa do Estado de São Paulo

scholarly journals Calcein staining of calcified structures in pearl oyster Pinctada margaritifera and the effect of food resource level on shell growth

Aquaculture ◽  
2011 ◽  
Vol 313 (1-4) ◽  
pp. 149-155 ◽  
Author(s):  
Clémentine Linard ◽  
Yannick Gueguen ◽  
Jacques Moriceau ◽  
Claude Soyez ◽  
Bélinda Hui ◽  
...  
Keyword(s):  
Shell Growth ◽  
Food Resource ◽  
Pearl Oyster ◽  
Pinctada Margaritifera ◽  
Resource Level ◽  
Effect Of Food

scholarly journals Revisiting the Organic Template Model through the Microstructural Study of Shell Development in Pinctada margaritifera, the Polynesian Pearl Oyster

Minerals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 370 ◽  
Author(s):  
Jean-Pierre Cuif ◽  
Yannicke Dauphin ◽  
Gilles Luquet ◽  
Kadda Medjoubi ◽  
Andrea Somogyi ◽  
...  
Keyword(s):  
Pearl Oyster ◽  
Nacreous Layer ◽  
Prismatic Layer ◽  
Pinctada Margaritifera ◽  
Microstructural Study ◽  
Leading Role ◽  
Complex Process ◽  
Gathering Data

A top-down approach to the mineralized structures and developmental steps that can be separated in the shells of Pinctada margaritifera was carried out. Detailed characterizations show that each of the two major layers usually taken into account (the outer prismatic layer and the inner nacreous layer) is actually the result of a complex process during which the microstructural patterns were progressively established. From its early growing stages in the deeper part of the periostracal grove up to the formation of the most inner nacreous layers, this species provides a demonstrative case study illustrating the leading role of specifically secreted organic structures as determinants of the crystallographic properties of the shell-building units. Gathering data established at various observational scales ranging from morphology to the nanometer level, this study allows for a reexamination of the recent and current biomineralization models.

scholarly journals POPULATION DYNAMICS OF MALAYAN LEAF FISH (Pristolepisgrooti Blkr.) IN RANAU LAKE, SOUTH SUMATRA

2018 ◽  
Vol 24 (2) ◽  
pp. 125
Author(s):  
Sevi Sawetri ◽  
Subagdja Subagdja ◽  
Dina Muthmainnah
Keyword(s):  
Mortality Rate ◽  
Growth Parameters ◽  
Total Mortality ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Frequency Data ◽  
Length Frequency ◽  
Lake Ecosystems ◽  
Exploitation Rate ◽  
Length Frequency Data

The Malayan leaf fish or locally named as kepor (Pristolepis grooti) is one of important biotic components in Ranau Lake ecosystems. This study aimed to estimate population dynamic and exploitation rate of kepor in Ranau Lake, South Sumatera. The population parameters are estimated based on length frequency data which were collected in March to October 2013. Growth parameters and fishing mortality rates were calculated using FiSAT software package. The results showed that kepor’s growth was negative allometric, which tended to gain length faster than weight. Kepor population was dominated (42%) by individual length of 10.0 to 11.0 cm. Predicted length infinity (L) was 17.28 cm with high value of growth rates (K) of 1.4 year-1. The natural mortality rate (M) is 2.57 year-1, the fishing mortality rate (F) is 5.36 year-1 and total mortality rate (Z) is 7.93 year-1. The exploitation rate of Malayan leaf fish in Ranau Lake (E = 0.68 year-1) has passed the optimum score.  

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