Seasonal distribution, abundance, and life-history traits of Greenland cod, Gadus ogac, at Wemindji, eastern James Bay

1991 ◽  
Vol 69 (12) ◽  
pp. 3061-3070 ◽  
Author(s):  
Bernard Morin ◽  
Christiane Hudon ◽  
Frederick Whoriskey

Greenland cod populations near Wemindji, eastern James Bay, were studied in 1987 and 1988 to describe the species' general ecology and life-history characteristics. During the summer, they principally occupied shallow (2–5 m) coastal waters. This habitat was characterized by a belt of eelgrass (Zostera marina) at depths of 1–3 m, salinities between 20 and 23‰, and temperatures of 3–20 °C. Daily trap catches were highly variable, and more fish were caught at night than during the day. In winter, more cod were found inshore, in the estuary, than in coastal waters. This movement corresponds to the completion of sexual maturity; spawning occurs in April to June. Growth rate was linear for males and females. The age at maturity was 3 years and no trade-off was observed between growth and reproduction. Greenland cod spawned every year, and the maximum age was 9 years. Life-history variables for Greenland cod differ from those of most arctic benthic fishes; this species shows rapid growth, high fecundity, low age at maturity, and high mortality. These characteristics may represent important adaptations allowing cod to sustain life in James Bay coastal waters, where environmental conditions are different from those in arctic waters.

2021 ◽  
Vol 28 (6) ◽  
pp. 327-332
Author(s):  
Muge Gidis ◽  
Eyup Baskale

The life history traits of the rough-tailed agama, Stellagama stellio (Linnaeus, 1758) in a population from Kütahya, Turkey were described by the skeletochronological method. From a total of 54 individuals, the mean ages ± standard deviation (SD) of males and females were calculated as 5.03 ± 2.076 years and 4.79 ± 1.584 years, respectively, and age distributions were not significantly different between sexes. The age at maturity was 2 years for both sexes. The longevity of females was 8 years, whereas for males it was 9 years. Mean snout-vent length (SVL) ± SD was 101.7 ± 9.6 mm in females and 104.9 ± 14.4 mm in males and did not significantly differ between the two sexes. We examined the sexual dimorphism of S. stellio in relation to the difference in population age structure between the sexes using the skeletochronological method. Male individuals were slightly larger than female individuals at the same age, but this difference was not statistically significant. We also estimated the maximum ages for S. stellio, which agree with other populations in Turkey.


2020 ◽  
Vol 27 (4) ◽  
pp. 195-200
Author(s):  
Ufuk Bülbül ◽  
Halime Koç ◽  
Yasemin Odabaş ◽  
Ali İhsan Eroğlu ◽  
Muammer Kurnaz ◽  
...  

Age structure of the eastern spadefoot toad, Pelobates syriacus from the Kızılırmak Delta (Turkey) were assessed using phalangeal skeletochronology. Snout-vent length (SVL) ranged from 42.05 to 86.63 mm in males and 34.03 to 53.27 mm in females. Age of adults ranged from 2 to 8 years in males and 3 to 5 years in females. For both sexes, SVL was significantly correlated with age. Males and females of the toads reached maturity at 2 years of age.


Diversity ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 3 ◽  
Author(s):  
Joshua Mouser ◽  
David Ashley ◽  
Tom Aley ◽  
Shannon Brewer

Non-native crayfish invasion is a major threat to many stream fauna; however, invasions in subterranean habitats are rarely documented. Our study objectives were to examine demographics and morphological and life-history traits of a gapped ringed crayfish Faxonius neglectus chaenodactylus population that invaded Tumbling Creek Cave and determine the effects of removal on the population. Crayfish were found throughout the cave though fewer individuals were observed upstream of an installed weir. Fecund females were collected in nearly all months, but were prevalent during spring (February–June). Males and females were of similar sizes. Males had larger chelae and chelae that were regenerated slightly more often than females. Removal of >4000 crayfish since 2011 resulted in reduced abundances, but the population persisted. Age estimates from counting bands on gastric mills indicated crayfish within the cave lived longer than populations in nearby Big Creek (6 vs. 4 years). Recent efforts to prevent upstream cave migrations included a barrier installation and since installation, few crayfish have been located upstream. We show that exploitation of new environments may lead to trait changes (i.e., reproduction and longevity). We also demonstrate that barriers reduce the spread of invasion at a comparable cost to removal. We hypothesize that increased reservoir elevation inundates springs hydrologically connected to the cave and this may be the invasion source.


2012 ◽  
Vol 90 (6) ◽  
pp. 758-765 ◽  
Author(s):  
Krysia N. Tuttle ◽  
Patrick T. Gregory

High-latitude environments are challenging for terrestrial ectotherms because short and cool active seasons generally limit the time available for foraging and growth, thereby negatively influencing life-history variables such as growth rate and age at maturity and ultimately, via fitness differences, their evolution. Many species show latitudinal clines in life-history traits, including growth rate and body size. We estimated growth curves of Plains Garter Snakes ( Thamnophis radix (Baird and Girard, 1853)) near the northern limit of the species’ range in central Alberta and compared our findings to similar estimates for more southerly populations. Despite a short growing season, female T. radix at Miquelon Lake grew rapidly, reaching maturity in 1 or 2 years, similar to southern populations, and attained greater maximum sizes than snakes in southern populations. Overall, growth in this high-latitude population is comparable with what is seen in other conspecific populations. Possible reasons for lack of marked latitudinal effect include longer days at high latitudes, highly productive aquatic habitats for foraging, effective thermoregulation, reduced competition, and (or) countergradient variation in growth rate.


2021 ◽  
Vol 9 ◽  
Author(s):  
Gabrielle Grenier ◽  
Aslak Smalås ◽  
Runar Kjær ◽  
Rune Knudsen

Sympatric Arctic charr, Salvelinus alpinus (L. 1758), morphs have flexible but repeated life history strategies tested across five Norwegian lakes. In several Scandinavian polymorphic Arctic charr populations differentiated by their diet and habitat use, a large littoral omnivorous (LO) morph commonly cooccurs with a smaller profundal spawning (PB/PZ) morph. A third, large piscivorous (PP) morph is also known to occur within a portion of Arctic charr populations in the profundal habitat along with the PB/PZ individuals. Life history traits, such as age at maturity, growth, and diet are known to differ among coexisting morphs. Notably, the PP morph was the longest morph with the oldest age at maturity while the PB/PZ morph showed the shortest lengths overall and youngest age with LO morph being intermediate in both traits. Growth parameters differed across all the morphs. When examining growth within morph groups, the LO morph was found to have different growth across all lakes, while similar reproductive investments and different energy acquisition patterns were seen within the PB/PZ and PP morphs. These results suggest repeat evolution in several life history strategies of reproductively isolated Arctic charr sympatric morphs, notably for the first time in the PP morph, while also highlighting the importance of the local environment in modulating life history traits.


2017 ◽  
Vol 372 (1712) ◽  
pp. 20160035 ◽  
Author(s):  
Anna Kuparinen ◽  
Jeffrey A. Hutchings

Life-history traits are generally assumed to be inherited quantitatively. Fishing that targets large, old individuals is expected to decrease age at maturity. In Atlantic salmon ( Salmo salar ), it has recently been discovered that sea age at maturity is under strong control by a single locus with sexually dimorphic expression of heterozygotes, which makes it less intuitive to predict how life histories respond to selective fishing. We explore evolutionary responses to fishing in Atlantic salmon, using eco-evolutionary simulations with two alternative scenarios for the genetic architecture of age at maturity: (i) control by multiple loci with additive effects and (ii) control by one locus with sexually dimorphic expression. We show that multi-locus control leads to unidirectional evolution towards earlier maturation, whereas single-locus control causes largely divergent and disruptive evolution of age at maturity without a clear phenotypic trend but a wide range of alternative evolutionary trajectories and greater trait variability within trajectories. Our results indicate that the range of evolutionary responses to selective fishing can be wider than previously thought and that a lack of phenotypic trend need not imply that evolution has not occurred. These findings underscore the role of genetic architecture of life-history traits in understanding how human-induced selection can shape target populations. This article is part of the themed issue ‘Human influences on evolution, and the ecological and societal consequences’.


2017 ◽  
Vol 25 (3) ◽  
pp. 145-155
Author(s):  
Fateme Taridashti ◽  
Javid Imanpour ◽  
Shahram Abdolmalaki ◽  
Mahvash Hadavi

Abstract This study was conducted to complement existing data about the life cycle of Caspian vimba, Vimba vimba (L.), with estimations of age, growth, and mortality rates. To achieve this, 811 specimens were collected between May 2012 and June 2013 at three fisheries catch stations in southwestern regions of the Caspian Sea including Talesh, Bandar Anzali, and Kiashahr. The growth rate in vimba is relatively high at approximately 0.29 year−1 for females and 0.32 year−1 for males. Asymptotic lengths are 245 mm and 233 mm for females and males, respectively. The growth pattern was isometric for both males and females. The overall sex ratio was balanced (1: 0.92). The instantaneous coefficients of total, natural, and fishing mortality were 1.27, 0.4, and 0.8 year, respectively, and the current exploitation ratio was 0.63 year−1. Results showed that the growth rate of males is higher than that of females. Considering the exploitation ratio, it is apparent that the vimba population is experiencing significant legal and illegal exploitation pressure.


1997 ◽  
Vol 54 (6) ◽  
pp. 1235-1245 ◽  
Author(s):  
M J Unwin ◽  
G J Glova

Chinook salmon (Oncorhynchus tshawytscha) spawning runs in Glenariffe Stream, New Zealand, exhibited significant changes in life history traits following supplementation releases of hatchery-reared juveniles. Total run strength did not change but the proportion of naturally produced fish declined to 34%. Attempts to separate spawners of natural and hatchery origin were unsuccessful, and 31-48% of natural spawners are now of hatchery origin. Hatchery males were smaller at age 2 and 3 than males of natural origin, and more often matured as jacks, producing an 86-mm decrease in mean fork length over 28 years. There was no change in length at age or age at maturity for female spawners. The proportion of jacks entering Glenariffe Stream each year was positively correlated with the proportion of jacks in the ensuing cohort. Most differences between fish of natural and hatchery origin were related to hatchery rearing practices, but the decline in age at maturity among naturally produced males appears to reflect traits inherited from parent stock of hatchery origin. Hatchery releases may also favour the survival of ocean-type fry over stream-type fry, possibly reversing a tendency for stream-type behaviour to evolve in response to the lack of estuaries on most New Zealand chinook salmon rivers.


Nematology ◽  
2005 ◽  
Vol 7 (3) ◽  
pp. 363-373 ◽  
Author(s):  
S. Patricia Stock ◽  
Ana Caicedo ◽  
Paul Calatayud

AbstractRhabditis (Oscheius) colombiana n. sp. is described as a necromenic associate of the burrower bug Cyrtomenus bergi (Hemiptera: Cydnidae) collected in the Cauca Valley, Colombia. The new species resembles others of the insectivora-group, viz, Rhabditis (O.) insectivora Körner, 1954 and Rhabditis (O.) lucianii Maupas, 1919, in a number of morphological and life history traits, but can be separated by a combination of morphological and morphometric characters. The most distinctive morphological features that separate R. (O.) colombiana n. sp. from these two Rhabditis species are the total size of both males and females, which are much shorter and slimmer in the new species; the size of the male spicules and the values of ratios b and c. Additionally, molecular data (18S rDNA sequences) and phylogenetic analyses demonstrated the distinctiveness of this species when compared to a number of other Rhabditis (Oscheius) species.


2016 ◽  
Vol 35 (5) ◽  
pp. 1189-1196 ◽  
Author(s):  
Muhammad Abu Bakar Siddik ◽  
Md Reaz Chaklader ◽  
Md Abu Hanif ◽  
Ashfaqun Nahar ◽  
Ilham Ilham ◽  
...  

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