Spatial variation in size and age structures and reproductive characteristics of the King George whiting (Percoidei : Sillaginidae) in South Australian waters

2000 ◽  
Vol 51 (1) ◽  
pp. 11 ◽  
Author(s):  
A. J. Fowler ◽  
L. McLeay ◽  
D. A. Short
Keyword(s):  
Gonad Development ◽  
South Australia ◽  
Size Distributions ◽  
Age Classes ◽  
Habitat Types ◽  
Histological Techniques ◽  
Geographic Regions ◽  
High Wave Energy ◽  
Age Range ◽  
Age Structures

Adult King George whiting were sampled at 12 localities representing a range of habitat types across South Australia. Sampling was undertaken between March and May for a minimum of 2 years between 1995 and 1998. Fish were aged by otolith interpretation, and reproductive maturity was determined by gonad analysis using macroscopic and histological techniques. In total, 6961 fish comprising 3678 females and 3283 males were considered from four localities in each of three geographic regions. In both Gulf St Vincent and Spencer Gulf, age structures became more complex from north to south, associated with a shift in size towards larger fish. In the simplest age structures, >90% of fish were from the 3-year age class, whereas the age range of the most complex was 3–17 years, with the 3–5 age classes most numerous. Males were more abundant in smaller size classes and females in the larger. Although some fish from each locality showed some gonad development, only at three localities did spawning occur. At these places, populations had the broadest age and size distributions and were in deep water that experienced medium to high wave energy. Since spawning grounds and nursery areas are up to several hundred kilometres apart, the processes of larval advection and adult movement are implicated as obligate processes of the life history.

Size Distributions and Growth of the Fan-shell Pinna bicolor Gmelin (Mollusca : Eulamellibranchia) in South Australia

1979 ◽  
Vol 30 (1) ◽  
pp. 25 ◽  
Author(s):  
AJ Butler ◽  
FJ Brewster
Keyword(s):  
South Australia ◽  
Adductor Muscle ◽  
Size Distributions ◽  
Limited Data ◽  
Length Frequency ◽  
Age Classes ◽  
Frequency Distributions ◽  
Growth And Survival ◽  
Random Samples ◽  
Variable Success

Fourteen random samples of Pinna bicolor were collected over a period of 31 months from 6 m depth in Gulf St Vincent off Edithburgh, South Australia. The length-frequency distributions suggest that: P. bicolor larvae settle in spring but with variable success; growth of newly settled young is rapid over summer; by age 1 year their modal shell length is about 20 cm; by age 2 it is about 26 cm; they may survive substantially longer than 3 years so that a length-class of mode c. 35 cm is always present and is composed of several age-classes not necessarily equally represented. These suggestions are corroborated by limited data on adductor muscle scars, the development of epibiota on the shells, and the growth and survival of tagged animals over 9 months.

Relationship between elemental concentration and age from otoliths of adult snapper (Pagrus auratus, Sparidae): implications for movement and stock structure

2005 ◽  
Vol 56 (5) ◽  
pp. 661 ◽  
Author(s):  
A. J. Fowler ◽  
B. M. Gillanders ◽  
K. C. Hall
Keyword(s):  
Mass Spectrometry ◽  
Inductively Coupled Plasma ◽  
Elemental Concentration ◽  
South Australia ◽  
Stock Structure ◽  
Habitat Types ◽  
Inductively Coupled ◽  
Age Related ◽  
Pagrus Auratus ◽  
Plasma Mass Spectrometry

The present study investigated the stock structure of snapper (Pagrus auratus) in South Australia, and the extent to which this is influenced by adult movement. Fish from the 9+ age class were sampled from six different regions, encompassing >2000 km of coastline and different habitat types. The chemistry of transverse sections of otoliths was sampled using laser ablation inductively coupled plasma-mass spectrometry, providing elemental profiles that were related to age for the first nine years of the fish’s lives. The age-related annual averages for both 88Sr and 138Ba differed significantly between regions. They were, however, similar for the first three years, then diverged considerably between the ages of three to five years, and then remained consistently different through to the age of nine years. This suggests that all fish, regardless of where captured, originated from only one or two nursery areas, but dispersed throughout the different regions between the ages of three to five years, before becoming resident to their new regions of occupancy. Thus, this population of snapper represents a single, large, stock where the individuals have a common origin, but through age-related emigration ultimately disperse and supplement the low abundance populations in regional State waters.

scholarly journals Estimating, monitoring, and forecasting COVID-19 epidemics: a spatiotemporal approach applied to NYC data

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vinicius V. L. Albani ◽  
Roberto M. Velho ◽  
Jorge P. Zubelli
Keyword(s):  
New York ◽  
New York City ◽  
Census Data ◽  
Age Group ◽  
Age Classes ◽  
Basic Model ◽  
Monitoring And Forecasting ◽  
Group Sex ◽  
Age Range ◽  
Spatial Locations

AbstractWe propose a susceptible-exposed-infective-recovered-type (SEIR-type) meta-population model to simulate and monitor the (COVID-19) epidemic evolution. The basic model consists of seven categories, namely, susceptible (S), exposed (E), three infective classes, recovered (R), and deceased (D). We define these categories for n age and sex groups in m different spatial locations. Therefore, the resulting model contains all epidemiological classes for each age group, sex, and location. The mixing between them is accomplished by means of time-dependent infection rate matrices. The model is calibrated with the curve of daily new infections in New York City and its boroughs, including census data, and the proportions of infections, hospitalizations, and deaths for each age range. We finally obtain a model that matches the reported curves and predicts accurate infection information for different locations and age classes.

Differential recovery of δ13C in multiple tissues of white sucker across age classes after the closure of a pulp mill

2014 ◽  
Vol 71 (5) ◽  
pp. 747-755 ◽  
Author(s):  
T.J. Arciszewski ◽  
A.J. Farwell ◽  
M.R. Servos ◽  
T.D. Jardine ◽  
K.R. Munkittrick
Keyword(s):  
Muscle Tissue ◽  
Pulp Mill ◽  
Pulp And Paper ◽  
White Sucker ◽  
Pulp Mills ◽  
Age Classes ◽  
Pulp And Paper Mills ◽  
Paper Mills ◽  
Gonad Tissue ◽  
Age Range

Techniques to document recovery after the closure of pulp mills that discharge enriching effluents are not well established, but δ13C may be a useful tool. In the 1990s, the muscle tissue of white sucker (Catostomus commersonii) collected downstream of two pulp and paper mills discharging into separate streams (Mattagami and Kapuskasing rivers) was enriched in 13C compared with upstream fish, suggesting uptake of pulp-derived C. The Mattagami River mill was closed in 2006, and analysis of muscle and gonad for δ13C was performed in 2011. As expected, fish captured in 2011 downstream of the operational Kapuskasing mill still showed the influence of the pulp-derived C in muscle and gonad tissue. After the closure of the Mattagami River mill, muscle tissue of white sucker was still enriched in 13C compared with upstream fish, while gonad tissue was not. The patterns observed in the Mattagami River were, however, related to age; the oldest fish showed enrichment of δ13C in both muscle and gonad tissue, suggesting the residual occurrence of pulp-derived C. This study suggests that measurements of stable isotopes in fish across a broad age range may indicate ecosystem improvements. These techniques may also be useful where no data prior to the upgrade or closure are available for comparison.

A Parapatric Boundary between Ranidella signifera and R. riparia (Anura: Leptodactylidae) in South Australia

1982 ◽  
Vol 30 (1) ◽  
pp. 49 ◽  
Author(s):  
FJ Odendaal ◽  
CM Bull
Keyword(s):  
Competitive Advantage ◽  
Close Association ◽  
South Australia ◽  
Wide Distribution ◽  
Habitat Types ◽  
South Eastern ◽  
The North ◽  
Flinders Ranges ◽  
Eastern Australia ◽  
Overlap Area

Ranidella signifera has a wide distribution in south-eastern Australia; R. riparia is endemic to the Flin- ders Ranges in South Australia. The ranges of the two species are largely allopatric, but they contact and overlap in a zone about 10 km wide, in the southern Flinders Ranges. The nature of the creeks changes across this zone. Immediately to the south and east, where only R. signifera is found, the creeks are slow-flowing and heavily vegetated, with mud or sand substrates. To the north and west the creeks are swift-flowing, and have rocky substrates and little vegetation; only R. riparia is found in these. In the sympatric overlap zone creeks are heterogeneous, with both habitat types represented. The close association between species and creek habitat is lost in populations not immediately adjacent to the overlap zone. This implies that each species can survive in both creek habitats but that R. riparia has a competitive advantage in swift, rocky creeks and R, signifera has an advantage in slow, vegetated creeks. This prevents either species from expanding its distribution beyond the narrow overlap area.

scholarly journals Histological analysis invalidates macroscopically determined maturity ogives of the Kattegat cod (Gadus morhua) and suggests new proxies for estimating maturity status of individual fish

2006 ◽  
Vol 63 (3) ◽  
pp. 485-492 ◽  
Author(s):  
F. Vitale ◽  
H. Svedäng ◽  
M. Cardinale
Keyword(s):  
Gadus Morhua ◽  
Histological Analysis ◽  
Spawning Season ◽  
Age Classes ◽  
Data Set ◽  
Histological Techniques ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Correct Estimation ◽  
Spawning Biomass

Abstract Assessment and management of fish populations currently rely on correct estimation of the spawning-stock biomass (SSB), which is based on accurate maturity ogives of the population. Although maturity ogives are usually calculated through macroscopic evaluation of the gonads, histology is generally considered to be more accurate. Here we show that the macroscopic analysis consistently overestimates the proportion of mature females for all age classes in Kattegat cod. The resulting bias showed minimum values for all age classes about a month before the spawning season. Consequently, estimation of the incidence of maturation in females several months before or after the spawning season can only be accurate using histological techniques. Further, the observed bias was used to reconstruct a historical data set of maturity ogives of Kattegat cod. The results showed that female spawning biomass (FSB) might have been overestimated by up to 35%. However, as histological analysis is considered a laborious procedure, proxies of maturity status were sought. It was indicated that the gonadosomatic and hepatosomatic indices may serve as robust proxies for discriminating mature females from immature, thus greatly enhancing the accuracy of the macroscopic maturity evaluation of cod gonads when histological analysis is lacking.

scholarly journals Diverse habitat use during two life stages of the critically endangered Bahama Oriole (Icterus northropi): community structure, foraging, and social interactions

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3500 ◽  
Author(s):  
Melissa R. Price ◽  
William K. Hayes
Keyword(s):  
Habitat Use ◽  
Social Interactions ◽  
Breeding Season ◽  
Pine Forest ◽  
Critically Endangered ◽  
Life Stages ◽  
Vegetation Types ◽  
Age Classes ◽  
Habitat Types ◽  
Second Year

Our ability to prevent extinction in declining populations often depends on effective management of habitats that are disturbed through wildfire, logging, agriculture, or development. In these disturbed landscapes, the juxtaposition of multiple habitat types can be especially important to fledglings and young birds, which may leave breeding grounds in human-altered habitat for different habitats nearby that provide increased foraging opportunities, reduced competition, and higher protection from predators. In this study, we evaluated the importance of three habitat types to two life stages of the critically endangered Bahama Oriole (Icterus northropi), a synanthropic songbird endemic to Andros, The Bahamas. First, we determined the avian species composition and relative abundance of I. northropi among three major vegetation types on Andros: Caribbean pine (Pinus caribaea) forest, coppice (broadleaf dry forest), and anthropogenic areas, dominated by nonnative vegetation (farmland and developed land). We then compared the foraging strategies and social interactions of two age classes of adult Bahama Orioles in relation to differential habitat use. Bird surveys late in the Bahama Oriole’s breeding season indicated the number of avian species and Bahama Oriole density were highest in coppice. Some bird species occurring in the coppice and pine forest were never observed in agricultural or residential areas, and may be at risk if human disturbance of pine forest and coppice increases, as is occurring at a rapid pace on Andros. During the breeding season, second-year (SY) adult Bahama Orioles foraged in all vegetation types, whereas after-second-year (ASY) adults were observed foraging only in anthropogenic areas, where the species nested largely in introduced coconut palms (Cocos nucifera). Additionally, SY adults foraging in anthropogenic areas were often observed with an ASY adult, suggesting divergent habitat use for younger, unpaired birds. Other aspects of foraging (vegetation features, food-gleaning behavior, and food items) were similar for the two age classes. Older Bahama Orioles exhibited relatively higher rates of social interactions (intraspecific and interspecific pooled) in anthropogenic areas, and won more interaction outcomes compared to younger adults. Our findings concur with those of other studies indicating dry broadleaf forest is vitally important to migrating, wintering, and resident birds, including the critically endangered Bahama Oriole, which appears to depend heavily on this vegetation type during certain life stages.

Characteristics and consequences of movement patterns of King George whiting (Perciformes : Sillaginodes punctata) in South Australia

2002 ◽  
Vol 53 (7) ◽  
pp. 1055 ◽  
Author(s):  
A. J. Fowler ◽  
G. K. Jones ◽  
R. McGarvey
Keyword(s):  
Fishery Management ◽  
South Australia ◽  
Shallow Waters ◽  
Rocky Reef ◽  
Fish Movement ◽  
The South ◽  
Age Classes ◽  
Australian Population ◽  
Northern Areas ◽  
Considerable Period

The characteristics of movement of the South Australian population of King George whiting (Sillaginodes punctata) were determined through analysis of tag and recapture records collected from three tagging periods: (i) 1968–1969; (ii) 1978–1985; and (iii) 1986–1987. The characteristics were compared between the northern and southern parts of two large fishery regions, and determined for fish tagged at different sizes and ages. Fish tagged in the northern Gulf St Vincent and Spencer Gulf moved southwards up to several hundred kilometres, but those tagged in the southern areas showed no systematic directional displacement. Most fish tagged were subadults or young, immature adults at 2–4 years of age. Small, young fish did not move far until a considerable period after tagging, whereas some fish >300 mm total length (TL) at tagging moved substantial distances within only a few weeks. Fish movement resulted in a significant ontogenetic habitat shift, from relatively protected shallow waters that support extensive meadows of seagrass, to southern, exposed, deeper waters and rocky reef. As a result of this systematic, directional displacement the age structures of the fishery catches also varied systematically throughout the two regions. In the northern areas these were simple and dominated by the 3+ age class, whereas in the south they were complex and consisted of the 2+ to 17+ age classes. Because the latter were the spawning populations, fish movement is an obligate step in the life history that ultimately results in supplementation of numbers on the spawning grounds. The consequences for fishery management are discussed.

Length and age compositions and growth rates of the Australian herring Arripis georgiana in different regions

2000 ◽  
Vol 51 (6) ◽  
pp. 631 ◽  
Author(s):  
D. V. Fairclough ◽  
W. F. Dimmlich ◽  
I. C. Potter
Keyword(s):  
Western Australia ◽  
Growth Rates ◽  
Coastal Waters ◽  
Growth Parameters ◽  
South Australia ◽  
Von Bertalanffy ◽  
Age Classes ◽  
Growth Coefficient ◽  
Spawning Areas ◽  
Marked Decline

Arripis georgiana was collected from coastal waters in Western Australia and South Australia. The opaque zones on the otoliths were shown to be formed annually and thus their number could be used to age the individuals of this species. Although the catches of A. georgiana in south-western Australia, where spawning occurs, were dominated by the 0+ to 5+ age classes, they did contain females and males up to ten and nine years old, respectively. The von Bertalanffy growth parameters for the two sexes in this region differed significantly, with the asymptotic length (L∞) being significantly greater for females (262 mm) than for males (239 mm), whereas the reverse was true for the growth coefficient (k), i.e. 0.813 v. 0.992. The catches of A. georgiana eastwards of 121˚44′E on the south coast of Western Australia, where spawning does not occur, were dominated by the 0+ to 2+ age classes. The above data, when taken in conjunction with earlier tagging experiments and the marked decline that occurs in the number of 2+ fish in South Australia in summer, imply that, during this period, many two-year-old individuals of A. georgiana start migrating towards their spawning areas in south-western Australia.

Geographic patterns in the genetic diversity of a northern sedge, Carex rariflora

1999 ◽  
Vol 77 (2) ◽  
pp. 269-278 ◽  
Author(s):  
Mark Vellend ◽  
Marcia J Waterway
Keyword(s):  
Genetic Diversity ◽  
Geographic Distance ◽  
Detrended Correspondence Analysis ◽  
Allozyme Variation ◽  
Glacial Refugium ◽  
Strong Positive Correlation ◽  
Habitat Types ◽  
Low Genetic Diversity ◽  
Habitat Differences ◽  
Geographic Regions

We compared the genetic diversity of a northern wetland sedge, Carex rariflora, both within and between populations, in different habitat types, and across geographic regions with different glacial histories. Twelve populations were sampled: 5 from each of two regions in northern Quebec, and 2 from northern Yukon. Habitat types were medium to rich fens, wet tidal flat, and alpine stream edge. Allele frequency data revealed a low degree of within-population genetic diversity (HS = 0.07) and a high degree of genetic differentiation among populations (GST = 0.47) compared with previously studied northern wetland Carex species. Higher genetic variability found in the Yukon than in Quebec could be explained by the presence of a glacial refugium in much of Alaska and the Yukon throughout the Pleistocene. Low genetic diversity in Quebec suggests the occurrence of genetic bottlenecks resulting from founder effects during postglacial colonization. There was a strong positive correlation between geographic distance and genetic distance among populations, and the three geographic regions were genetically distinct from one another. Detrended correspondence analysis of vegetation data revealed clear differences among the three habitat types, but we found no significant correlation between habitat differences and genetic distance.Key words: allozyme variation, genetic diversity, geographic variation, Carex rariflora.

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