Population ecology of a cryptic arboreal snake (Hoplocephalus bitorquatus)

2017 ◽  
Vol 65 (6) ◽  
pp. 383 ◽  
Author(s):  
Michael B. Shelton ◽  
Ross L. Goldingay ◽  
Stephen S. Phillips
Keyword(s):  
Population Structure ◽  
Population Ecology ◽  
Growth Rates ◽  
Sexual Maturity ◽  
Capture Probability ◽  
Von Bertalanffy ◽  
Growth Modelling ◽  
Mark Recapture ◽  
Data Deficient ◽  
Arboreal Snakes

Biologists have traditionally been reluctant to study arboreal snakes due to low rates of capture. Overlooking such taxa can mislead interpretations of population trends for data-deficient species. We used regularly spaced transect searches and standard capture–mark–recapture techniques to describe population structure, growth rates, survival and capture probability in a population of the pale-headed snake (Hoplocephalus bitorquatus) in southern Queensland. We obtained data from 194 captures of 113 individual snakes between 2009 and 2015. Using the Cormack–Jolly–Seber method, we estimated apparent annual survival in subadult snakes at 0.23 ± 0.01 (s.e.) and 0.81 ± 0.08 for adults. Capture probability was estimated at 0.16 ± 0.14 per session in subadult snakes and 0.33 ± 0.06 for adults. Within the red gum forests of our study site, we estimate pale-headed snake density at ~13 ± 7 ha–1. Using von Bertalanffy growth modelling, we predict that snakes reach sexual maturity after about four years and may live for up to 20. Our results suggest that the species is a ‘k’ strategist, characterised by slow maturation and low fecundity. These traits suggest that populations will recover slowly following decline, exacerbating the risk of local extinction.

Advances in Fish Tagging and Marking Technology

2012 ◽  
Keyword(s):  
Population Structure ◽  
Growth Rates ◽  
Inductively Coupled Plasma ◽  
Sexual Maturity ◽  
Current Data ◽  
Otolith Chemistry ◽  
Inductively Coupled ◽  
Spatial Differences ◽  
General Movement ◽  
The 1960S

<i>Abstract</i>.—The population structure of the eastern Australian salmon <i>Arripis trutta </i>stock in the waters of southeastern (SE) Australia was examined using information provided by historical as well as current data sources. An extensive tag-recapture program and aging study undertaken during the 1960s demonstrated widespread mixing of the <i>A. trutta </i>population in SE Australian waters and established a robust model of general movement of fish from Tasmania north to Victoria and NSW with the approach of sexual maturity at ~four years of age. However, this work also hypothesized that the portion of the stock at Flinders Island in Tasmanian waters was resident and did not undergo this northward migration. Otolith chemistry analyses were therefore used as a tool in a ‘weight of evidence’ approach to further examine the population structure of the <i>A. trutta </i>stock in SE Australia. Samples of five year old <i>A. trutta </i>for analysis of otolith chemistry were collected over seven weeks from two sites (10 per site) within each of four locations: northern NSW, southern NSW, Victoria and Tasmania. The cores and edges of otoliths were analyzed using laser ablation inductively coupled plasma mass spectrometry. Univariate analyses did not find spatial differences for any of the elements Li, Na, Mg, Mn, Ba or Sr between locations. Multivariate analyses however, did find differences between the multi-element ‘fingerprints’ of fish from Tasmania compared to each of the other locations (which were similar). This difference was driven by a group of fish collected from Flinders Island in north-eastern Tasmanian waters. The fish collected at this site were also significantly smaller at five years of age than fish from all other sites, indicating reduced growth rates. The lack of consequential and definitive differences in otolith chemistry data combined with the highly migratory nature of <i>A. trutta </i>in this region demonstrated by tagging studies confirm that the most likely stock structure model for <i>A. trutta </i>in SE Australia is of a single well mixed biological stock spanning Tasmania, Victoria and NSW with fish moving north from Tasmania to mainland Australia with the approach of sexual maturity. However, the reduced growth rates and distinct elemental signature for <i>A. trutta </i>from Flinders Island highlights the need for further work to examine the preexisting hypothesis of a potential resident sub-population there.

Growth in a cold environment: body size and sexual maturity in a northern population of spotted turtles, Clemmys guttata

1998 ◽  
Vol 76 (5) ◽  
pp. 773-782 ◽  
Author(s):  
Jacqueline D Litzgus ◽  
Ronald J Brooks
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Growth Rates ◽  
Sexual Maturity ◽  
Carapace Length ◽  
Temperate Climate ◽  
Von Bertalanffy ◽  
Adult Body Size ◽  
Clemmys Guttata ◽  
Adult Body

Using mark-recapture data collected from 1978 to 1997, we examined growth rates, adult body size, and age and size at sexual maturity of spotted turtles (Clemmys guttata) in a northern temperate climate. Relative instantaneous growth rate analyses indicated that growth rates were inversely related to body size, individual variation in growth rate was high, and females and males did not differ with respect to growth rates. Growth of our spotted turtles was described well by both the von Bertalanffy and logistic growth models, although the von Bertalanffy model provided a slightly better fit to our data. Asymptotic sizes and intrinsic growth factors did not differ between the sexes. Northern spotted turtles reach a larger mean adult body size relative to southern populations. Turtles were not sexually size dimorphic with respect to carapace length; however, plastron length was greater in females than in males. Sexual maturity was reached at a larger size (a carapace length of approximately 103 mm for females and 105 mm for males) and estimated age (12-15 years for females and 11-13 years for males) in northern spotted turtles relative to more southerly conspecifics.

Population structure, age and growth rates of conifer species and their relation to environmental variables at Malam Jabba, Swat District, Pakistan

2018 ◽  
Vol 31 (2) ◽  
pp. 429-441
Author(s):  
Arsalan ◽  
Muhammad Faheem Siddiqui ◽  
Moinuddin Ahmed ◽  
Syed Shahid Shaukat ◽  
Alamdar Hussain
Keyword(s):  
Population Structure ◽  
Growth Rates ◽  
Environmental Variables ◽  
Age And Growth ◽  
Conifer Species

scholarly journals Population structure and reproductive characteristics of the silky shark Carcharhinus falciformis (Müller & Henle, 1839) (Carcharhiniformes: Carcharhinidae) off the coast of Oaxaca, Mexico

2017 ◽  
Vol 44 (3) ◽  
pp. 513-524
Author(s):  
María del Carmen Alejo-Plata ◽  
Miguel Ángel Ahumada-Sempoal ◽  
José Luis Gómez-Márquez ◽  
Adrián González-Acosta
Keyword(s):  
Population Structure ◽  
Sex Ratio ◽  
Seasonal Changes ◽  
Sexual Maturity ◽  
Size Structure ◽  
Landing Sites ◽  
Silky Shark ◽  
Oceanic Species ◽  
Carcharhinus Falciformis ◽  
Gravid Females

Carcharhinus falciformis is an abundant oceanic species, which occurs in equatorial and tropical zones, with an important catch in the Atlantic and Pacific coasts of Mexico. Samples were taken from December 2000 to December 2007 in four landing sites of the artisanal fleet on the coast of Oaxaca. During the period of study 1236 specimens (602 females and 634 males) of C. falciformis were registered. Total length (TL) ranged from 49 to 217 cm for females (mean = 111.3 cm) and from 59 to 265 cm for males (mean = 111.7 cm). The sex ratio of females to males was 1:1 ( 2 0.05 = 0.78, P > 0.05). The present data suggest a size at first sexual maturity of about 184.8 cm TL for females and 178.5 cm TL for males. The catches were composed mainly of young. In the 52 gravid females examined, the average number of embryos per female was seven; with a range of 3-14 embryos. Mean TL of embryos ranged from 10 to 66 cm with evidence of seasonal changes in the size structure. Results obtained showed that C. falciformis gives birth most of the year, with the highest proportion of births during the rainy season (May to October).

Marbled lungfish growth rates in Lake Baringo, Kenya, estimated by mark-recapture

2006 ◽  
Vol 68 (2) ◽  
pp. 443-449 ◽  
Author(s):  
R. Dunbrack ◽  
J. M. Green ◽  
C. M. Mlewa
Keyword(s):  
Growth Rates ◽  
Mark Recapture

Selection on growth rates via a trade-off between survival to sexual maturity and longevity in the swordtail fish Xiphophorus multilineatus

2019 ◽  
Vol 33 (4) ◽  
pp. 549-566 ◽  
Author(s):  
Michael Weinstein ◽  
Melissa N. Liotta ◽  
Aaron Solitt ◽  
Adam Hunt ◽  
Jessica K. Abbott ◽  
...  
Keyword(s):  
Growth Rates ◽  
Sexual Maturity ◽  
Trade Off ◽  
Swordtail Fish

scholarly journals Impact of Feed Rations on Growth, Selected Body Parameters and Maturation of Vendace, Coregonus Albula L., Reared in RAS

2014 ◽  
Vol 22 (2) ◽  
pp. 145-150
Author(s):  
Bożena Szczepkowska ◽  
Mirosław Szczepkowski ◽  
Iwona Piotrowska
Keyword(s):  
Growth Rates ◽  
Sexual Maturity ◽  
Fish Growth ◽  
Coregonus Albula ◽  
Body Weights ◽  
Intensive Rearing ◽  
Mature Fish ◽  
Final Survival ◽  
Body Parameters ◽  
Commercial Size

Abstract Vendace, Coregonus albula L., was reared to commercial size in a recirculating system. Three different feed rations were applied during the ten-month-long experiment. The feed rations impacted fish growth rates, and fish in the different groups achieved body weights of 26.6 g to 57.5 g. The final survival in all groups was similar from 44.3% among the fish fed the smallest feed ration to 53.2% in the group receiving the largest feed ration. No differences were noted in the share of viscera, peritoneal fat, or in the hepatosomatic indexes, but there were differences in the gonadosomatic indexes. After thermal stimulation, only males achieved sexual maturity. The number of mature fish was similar in all groups and ranged from 17.8 to 21.3% of all fish. The results of the present study indicated that vendace can achieve commercial size in an intensive rearing period of ten months in RAS.

Age, Growth, and Sexual Maturity of the Shorthorn Sculpin, Myoxocephalus scorpius, in Newfoundland Waters

1970 ◽  
Vol 27 (12) ◽  
pp. 2155-2158 ◽  
Author(s):  
G. P. Ennis
Keyword(s):  
Growth Rates ◽  
Sexual Maturity ◽  
Average Length ◽  
Maximum Size ◽  
Age Group ◽  
Younger Age ◽  
Shorthorn Sculpin ◽  
Males And Females ◽  
The Difference ◽  
Myoxocephalus Scorpius

In Newfoundland waters, shorthorn sculpins, Myoxocephalus scorpius (L.), live to age 15 and attain a maximum size of just over 50 cm. The growth rates of males and females are little different below age 4, but above age 4 the females grow faster than the males, and the difference between average length-at-age for males and females gets progressively larger with age. Males mature at a younger age and at a smaller size than females. In any age-group where there are mature and immature individuals the mature ones are larger.

Adaptation and evolution in Gallotia lizards from the Canary Islands: age, growth, maturity and longevity

1991 ◽  
Vol 12 (1) ◽  
pp. 81-102 ◽  
Author(s):  
Jacques Castanet ◽  
Marcos Baez
Keyword(s):  
Canary Islands ◽  
Growth Rates ◽  
Sexual Maturity ◽  
Maximum Size ◽  
Adaptive Strategies ◽  
Relative Growth ◽  
Qualitative And Quantitative ◽  
Evolutionary Features ◽  
Histological Data

AbstractQualitative and quantitative comparisons of histological data recorded from growing bone from seven extant and extinct taxa of Gallotia show that these lizards do not have the same longevity, reach sexual maturity at various ages and probably have different growth rates which are in reverse proportion to the specific size of individuals in each taxon. In term of relative growth, the highest rate is seen in the smallest taxon (G. atlantica) and the lowest in the largest taxon (G. goliath). It appears that differences between the maximum size reached, irrespective of the size of hatchlings, are only the consequence of changes in longevity allowing a more or less protracted growth; they are not due to differences in growth rates. On the basis of these data we discuss some points relating to adaptive strategies and evolutionary features of these lizards.

scholarly journals Population Structure and Some Growth Properties of Gibel Carp (Carassius gibelio) in a Mesotrophic Lake

2016 ◽  
Vol 8 (3) ◽  
pp. 286-291 ◽  
Author(s):  
Hakki DERELI ◽  
Ezgi DİNÇTÜRK
Keyword(s):  
Population Structure ◽  
Trophic Status ◽  
Gibel Carp ◽  
Trophic State Index ◽  
Von Bertalanffy ◽  
Total Length ◽  
Carassius Gibelio ◽  
Mesotrophic Lake ◽  
Growth Properties ◽  
Lake Beysehir

The hereby study investigated gibel carp (Carassius gibelio) in a mesotrophic lake (Lake Beyşehir, Turkey) from April 2013 to March 2014, in order to outline population structure and some growth properties of the species. Two water quality variables (Chlorophyll-a, Trophic State Index (TSI)) were detected seasonally to define trophic status of the lake. Length and weight distributions, length - weight relationship, sex ratio, gonadosomatic index (GSI), condition factor (CF) and von Bertalanffy equation were calculated for C. gibelio sampled monthly. Trophic status of the lake was defined as mesotrophic. Total length and weight of C. gibelio samples was determined in the range of 8.5 and 28.4 cm and 15 and 408 g, respectively. Mean total length and weight of individuals were calculated as 17.5 ± 2.37 cm and 88.6 ± 39.02 g, respectively. There was a negative allometry between length and weight for C. gibelio. The fish samples were composed of 52% females and 48% males, between II and VII years old. Spawning period of the species occurred between April and June after GSI values reached their maximum in March. The CF values were validated between 1.5-1.7 besides the mean rate of females and males were 1.6 and 1.5, respectively. The parameters of von Bertalanffy equation were calculated as L∞: 19.8 cm, W∞: 652.9 gr, k: 0.934. In conclusion, C. gibelio has almost lost the economic value since the individuals are smaller than market size (≥ 250 g), probably due to lack of nutrients/mesotrophic situation of Lake Beyşehir.

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