scholarly journals Population Dynamics of the White Spotted Rabbitfish (Siganus canaliculatus Park, 1797) in Panguil Bay, Philippines

2020 ◽  
Vol 5 (9) ◽  
pp. 295-301
Author(s):  
Alejandro M. Gonzaga, Jr
Keyword(s):  
Population Dynamics ◽  
Management Strategies ◽  
Northern Coast ◽  
Recruitment Pattern ◽  
Instantaneous Rate ◽  
Siganus Canaliculatus ◽  
Estimated Parameters ◽  
Gill Net ◽  
Commercially Important ◽  
Rabbitfish Siganus Canaliculatus

The white spotted rabbitfish (Siganus canaliculatus Park, 1797) is a commercially important commodity occurring in the northern coast and southern coast of Panguil Bay. This fish was reported to be caught by fishing gears like filter net, fish corral, bottom set gill net, stationary lift net, motorized scissors net, and spear. To understand the population dynamics and associated status of white spotted rabbitfish in Panguil Bay, the growth, mortality, exploitation and recruitment pattern were determined from June 2002 to May 2003. A total of 1,513 samples of white spotted rabbitfish were collected from the four sampling stations established in Panguil Bay. Growth was estimated using the FiSAT II and the estimated parameters were L∞ = 33.20 cm and K = 0.54 yr-1. Total, natural and fishing instantaneous rate of mortality values were Z = 3.80 yr-1 , M = 1.18 yr-1 , F = 2.62 yr-1 and the exploitation rate value was E = 0.69 yr1 . Projected recruitment pattern of S. canaliculatus suggests that this species spawns all year round. Based on the results, S. canaliculatus caught by fish corral in Panguil Bay from June 2002 to May 2003 was overexploited and that management strategies of this resource must be promulgated and implemented to address the depleting fishery.

scholarly journals Population dynamics of the mullet fish, Rhinomugil corsula (Hamilton, 1822), in the Sitakunda coast of the Bay of Bengal

2019 ◽  
Vol 47 (2) ◽  
pp. 305-314 ◽  
Author(s):  
Syeda Ismat Ara ◽  
MA Azadi ◽  
Munira Nasiruddin ◽  
Aftab Hossain ◽  
MG Mustafa
Keyword(s):  
Population Dynamics ◽  
Bay Of Bengal ◽  
Relative Yield ◽  
Total Mortality ◽  
Recruitment Pattern ◽  
Instantaneous Rate ◽  
A Minor ◽  
Two Peaks ◽  
Yield Per Recruit ◽  
Rhinomugil Corsula

Population dynamics of the mullet species, Rhinomugil corsula, was studied, using FiSAT-II program, with the length-frequency data of 2480 fish specimens. The asymptotic length (L∞) and growth coefficient (K) of this fish were estimated to be 31.4 cm and 1.0/year, respectively. The instantaneous rate of natural mortality (M), fishing mortality (F) and total mortality (Z) were estimated to be 1.73, 1.20 and 2.93, respectively. The recruitment pattern of the species was prolonged with two peaks, major peak during June to December and a minor peak during January to April. The L25, L50 and L75 were found to be 8.61, 10.42 and 12.23 cm, respectively. The relative yield per recruit (Yʹ/R) and biomass per recruit (Bʹ/R) were 0.751 and 1.731, respectively. The value of exploitation (E) was found to be 0.41 which indicated that R. corsula was not over fished (E > 0.50) in the study area. The maximum exploitation (Emax) value was 0.55. The growth performance index (ϕ´ = 2.99) of R. corsula in the Sitakunda coast of the Bay of Bengal was found to be moderate. Bangladesh J. Zool. 47(2): 305-314, 2019

scholarly journals Population dynamics of the pea crab Austinixa aidae (Brachyura, Pinnotheridae): a symbiotic of the ghost shrimp Callichirus major (Thalassinidea, Callianassidae) from the southwestern Atlantic

2011 ◽  
Vol 101 (1-2) ◽  
pp. 5-14 ◽  
Author(s):  
Douglas F Peiró ◽  
Fernando L Mantelatto
Keyword(s):  
Population Dynamics ◽  
Sandy Beach ◽  
Southwestern Atlantic ◽  
Recruitment Pattern ◽  
Size Frequency Distribution ◽  
Ghost Shrimp ◽  
Density Values ◽  
Pea Crab ◽  
Biological Aspects ◽  
The Mean

The Pinnotheridae family is one of the most diverse and complex groups of brachyuran crabs, many of them symbionts of a wide variety of invertebrates. The present study describes the population dynamics of the pea crab Austinixa aidae (Righi, 1967), a symbiont associated with the burrows of the ghost shrimp Callichirus major (Say, 1818). Individuals (n = 588) were collected bimonthly from May, 2005 to September, 2006 along a sandy beach in the southwestern Atlantic, state of São Paulo, Brazil. Our data indicated that the population demography of A. aidae was characterized by a bimodal size-frequency distribution (between 2.0 and 4.0 mm and between 8.0 and 9.0 mm CW) that remained similar throughout the study period. Sex ratio does not differ significantly from 1:1 (p > 0.05), which confirms the pattern observed in other symbiontic pinnotherids. Density values (1.72 ± 1.34 ind. • ap.-1) are in agreement with those found for other species of the genus. The mean symbiosis incidence (75.6%) was one of the highest among species of the Pinnotheridae family, but it was the lowest among the three studied species of the genus. Recruitment pattern was annual, beginning in May and peaking in July, in both years, after the peak of ovigerous females in the population (from March to May). Our findings describe ecological and biological aspects of A. aidae similar to those of other species of this genus, even from different geographic localities.

scholarly journals 2nd International Arctic Ungulate Conference

Rangifer ◽  
1996 ◽  
Vol 16 (2) ◽  
pp. 49
Author(s):  
A. Anonymous
Keyword(s):  
Population Dynamics ◽  
Behavior Genetics ◽  
Management Strategies ◽  
The United States ◽  
Research Unit ◽  
Federal Agencies ◽  
Lessons Learned ◽  
Ecosystem Level ◽  
Commercial Organizations ◽  
The University

The 2nd International Arctic Ungulate Conference was held 13-17 August 1995 on the University of Alaska Fairbanks campus. The Institute of Arctic Biology and the Alaska Cooperative Fish and Wildlife Research Unit were responsible for organizing the conference with assistance from biologists with state and federal agencies and commercial organizations. David R. Klein was chair of the conference organizing committee. Over 200 people attended the conference, coming from 10 different countries. The United States, Canada, and Norway had the largest representation. The conference included invited lectures; panel discussions, and about 125 contributed papers. There were five technical sessions on Physiology and Body Condition; Habitat Relationships; Population Dynamics and Management; Behavior, Genetics and Evolution; and Reindeer and Muskox Husbandry. Three panel sessions discussed Comparative caribou management strategies; Management of introduced, reestablished, and expanding muskox populations; and Health risks in translocation of arctic ungulates. Invited lectures focused on the physiology and population dynamics of arctic ungulates; contaminants in food chains of arctic ungulates and lessons learned from the Chernobyl accident; and ecosystem level relationships of the Porcupine Caribou Herd.

scholarly journals Separating the effects of climate, bycatch, predation and harvesting on tītī (Ardenna grisea) population dynamics in New Zealand: A model-based assessment

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243794
Author(s):  
Sam McKechnie ◽  
David Fletcher ◽  
Jamie Newman ◽  
Corey Bragg ◽  
Peter W. Dillingham ◽  
...  
Keyword(s):  
Population Dynamics ◽  
New Zealand ◽  
Southern Oscillation ◽  
Population Decline ◽  
Management Strategies ◽  
Model Averaging ◽  
Adult Survival ◽  
Enso Events ◽  
Introduced Predators ◽  
Best Fitting

A suite of factors may have contributed to declines in the tītī (sooty shearwater; Ardenna grisea) population in the New Zealand region since at least the 1960s. Recent estimation of the magnitude of most sources of non-natural mortality has presented the opportunity to quantitatively assess the relative importance of these factors. We fit a range of population dynamics models to a time-series of relative abundance data from 1976 until 2005, with the various sources of mortality being modelled at the appropriate part of the life-cycle. We present estimates of effects obtained from the best-fitting model and using model averaging. The best-fitting models explained much of the variation in the abundance index when survival and fecundity were linked to the Southern Oscillation Index, with strong decreases in adult survival, juvenile survival and fecundity being related to El Niño-Southern Oscillation (ENSO) events. Predation by introduced animals, harvesting by humans, and bycatch in fisheries also appear to have contributed to the population decline. It is envisioned that the best-fitting models will form the basis for quantitative assessments of competing management strategies. Our analysis suggests that sustainability of the New Zealand tītī population will be most influenced by climate, in particular by how climate change will affect the frequency and intensity of ENSO events in the future. Removal of the effects of both depredation by introduced predators and harvesting by humans is likely to have fewer benefits for the population than alleviating climate effects.

Black Bass Diversity: Multidisciplinary Science for Conservation

2015 ◽  
Keyword(s):  
Population Dynamics ◽  
Management Strategies ◽  
Smallmouth Bass ◽  
Micropterus Dolomieu ◽  
Spawning Period ◽  
Sampling Gear ◽  
Gray Literature ◽  
Black Bass ◽  
Effective Conservation ◽  
Conservation And Management

<em>Abstract</em>.—We reviewed the published and gray literature associated with Neosho Smallmouth Bass <em>Micropterus dolomieu velox</em> and the genetically distinct Ouachita lineage. Substantial interstream variation appears to occur among these populations, particularly related to age. The Neosho subspecies is more abundant, grows faster, and lives longer than the genetically distinct Ouachita lineage. Recruitment is highly variable among streams for both populations and appears to be related to some undescribed aspects of hydrology but also likely reflect bias due to sampling gear. Information on annual and seasonal trends is lacking for the Neosho subspecies and the Ouachita lineages, particularly as related to the spawning period. Conservation efforts for these lineages might benefit from agencies partnering to achieve goals that extend beyond a particular agency’s responsibilities and state boundaries. Recognition of spatial and temporal considerations, combined with a better understanding of the population dynamics as related to abundance, growth, mortality and reproduction, would benefit the creation of more effective conservation and management strategies for genetically distinct populations of Smallmouth Bass <em>M. dolomieu</em>.

scholarly journals Modeling the Population Dynamics and Economics of Velvetleaf (Abutilon theophrasti) Control in a Corn (Zea mays)-Soybean (Glycine max) Rotation

Weed Science ◽  
1995 ◽  
Vol 43 (2) ◽  
pp. 269-275 ◽  
Author(s):  
John L. Lindquist ◽  
Bruce D. Maxwell ◽  
Douglas D. Buhler ◽  
Jeffrey L. Gunsolus
Keyword(s):  
Population Dynamics ◽  
Weed Management ◽  
Management Practices ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Parameter Estimates ◽  
Economic Returns ◽  
Net Return ◽  
Herbicide Use ◽  
Optimum Threshold

A simulation model was developed to predict the population dynamics and economics of velvetleaf control in a corn-soybean rotation. Data compiled from the literature were used to parameterize the model for two situations, one in which velvetleaf was infected by aVerticilliumspp. wilt and one without infection.Verticilliumwas assumed to have no effect on corn or soybean yield. In the absence of control, simulated seedbank densities of aVerticillium-infected velvetleaf population were 5 to 50 times lower than for an uninfected velvetleaf population. The model was used to evaluate a threshold weed management strategy under the assumption that velvetleaf was the only weed and bentazon the only herbicide available for its control. In the absence ofVerticillium, an economic optimum threshold of 2.5 seedlings 100 m−2afforded the highest economic returns after 20 yr of simulation. Simulations in which velvetleaf was infected in 8 out of 20 randomly assigned years indicated a 6% increase in annualized net return and an 11 % reduction in the number of years that control was necessary. Sensitivity analysis indicated the parameter estimates having the greatest impact on economic optimum threshold were seedling emergence and survival, maximum seed production, and herbicide efficacy. Under an economic optimum threshold of 2.5 seedlings 100 m−2, management practices that manipulate the most sensitive demographic processes increased annualized net return by up to 13% and reduced long-term herbicide use by up to 26%. Results demonstrate that combining an economic optimum threshold with alternative weed management strategies may increase economic return and reduce herbicide use.

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