Size at Sexual Maturity and Fecundity of the Fjord-dwelling Golden King Crab Lithodes Aequispina Benedict from Northern British Columbia

1985 ◽  
Vol 5 (3) ◽  
pp. 377-385 ◽  
Author(s):  
S. C. Jewett ◽  
N. A. Sloan ◽  
D. A. Somerton
Keyword(s):  
British Columbia ◽  
Sexual Maturity ◽  
King Crab ◽  
Size At Sexual Maturity

Comparative life history features of the western spotted frog, Rana pretiosa, from low- and high-elevation populations

1975 ◽  
Vol 53 (9) ◽  
pp. 1254-1257 ◽  
Author(s):  
Lawrence E. Licht
Keyword(s):  
British Columbia ◽  
Life History ◽  
Body Size ◽  
Sexual Maturity ◽  
High Elevation ◽  
The Body ◽  
Female Fecundity ◽  
Size At Sexual Maturity ◽  
Rana Pretiosa

Comparisons are made of life history features of the western spotted frog, Rana pretiosa pretiosa, living at 70 m in southwestern British Columbia, and 2600 m in Yellowstone Park, Wyoming.Lowland tadpoles remain longer as larvae and transform at twice the body size as highland tadpoles.Growth rates of juveniles and adults are rapid in the lowland population and the same amount of growth achieved by them in 2–3 years takes 8–10 years for highland frogs.Body size at sexual maturity is the same for frogs from both populations, but B.C. frogs breed at half the age of Wyoming frogs. Female fecundity, the number of eggs at spawning, is the same, but lowland females breed annually, while high-elevation females breed only every 2 or 3 years.Various explanations are put forth to account for observed differences.

scholarly journals Use of otoliths to estimate size at sexual maturity in fish

2000 ◽  
Vol 43 (4) ◽  
pp. 437-440 ◽  
Author(s):  
Carlos Sérgio Agostinho
Keyword(s):  
Sexual Maturity ◽  
Line Segments ◽  
Alternative Method ◽  
Straight Line ◽  
Size At Sexual Maturity

The viability of an alternative method for estimating the size at sexual maturity of females of Plagioscion squamosissimus (Perciformes, Sciaenidae) was analyzed. This methodology was used to evaluate the size at sexual maturity in crabs, but has not yet been used for this purpose in fishes. Separation of young and adult fishes by this method is accomplished by iterative adjustment of straight-line segments to the data for length of the otolith and length of the fish. The agreement with the estimate previously obtained by another technique and the possibility of calculating the variance indicates that in some cases, the method analyzed can be used successfully to estimate size at sexual maturity in fish. However, additional studies are necessary to detect possible biases in the method.

scholarly journals A comparison of the allometric growth in Uca leptodactyla (Crustacea: Brachyura: Ocypodidae) from two subtropical estuaries

2004 ◽  
Vol 84 (4) ◽  
pp. 733-735 ◽  
Author(s):  
Rosana Carina Flores Cardoso ◽  
Maria Lucia Negreiros-Fransozo
Keyword(s):  
Growth Pattern ◽  
Sexual Maturity ◽  
Carapace Length ◽  
Brazilian Coast ◽  
Allometric Growth ◽  
Size At Sexual Maturity ◽  
Subtropical Estuaries ◽  
Habitat Similarity

The allometric growth of Uca leptodactyla from two distinct subtropical estuaries on the Brazilian coast was evaluated concerning its growth pattern and size at onset of sexual maturity. Females attained maturity at similar sizes in both sites (4·1 mm of carapace length in Indaiá and 4·2 mm in Ubatumirim), while males differed slightly. They reached the size at sexual maturity of 5·3 mm of carapace length in Indaiá and 4·6 mm in Ubatumirim. Growth pattern is usually similar among crabs from distinct sites while size at sexual maturity is frequently different. However, in the case of U. leptodactyla it did not occur, probably due to the strong habitat similarity and intrinsic features of this species.

Breeding characteristics of Townsend's vole (Microtus townsendii) during population fluctuations

1980 ◽  
Vol 58 (4) ◽  
pp. 623-625 ◽  
Author(s):  
Terry D. Beacham
Keyword(s):  
British Columbia ◽  
Sexual Maturity ◽  
Fraser River ◽  
Population Fluctuations ◽  
Peak Density ◽  
Decline Phase ◽  
Early Maturing ◽  
Fraser River Delta ◽  
Peak Phase ◽  
Microtus Townsendii

A 2-year livetrapping study on Townsend's vole (Microtus townsendii) on Reifel Island in the Fraser River delta in British Columbia, Canada, showed that there was an early stop to summer breeding in the peak phase summer compared with the increasing phase summer. Selective dispersal and death of early-maturing voles may account for this result. A delay occurred in the onset of breeding in the decline phase. Voles in peak density populations had the highest median weights at sexual maturity, and males matured at heavier weights than did females.

scholarly journals Seasonal variations in the population biology of Salmostoma bacaila (Cyprinidae) from a tributary of the Payra River, Bangladesh

2019 ◽  
pp. 113-119
Author(s):  
Ahamed Ahamed ◽  
Faruque Ahmed Zoarder ◽  
Jun Ohtomi
Keyword(s):  
Sex Ratio ◽  
Seasonal Variations ◽  
Population Biology ◽  
Sexual Maturity ◽  
Condition Factor ◽  
Gonadosomatic Index ◽  
Spawning Season ◽  
Frequency Distributions ◽  
Size At Sexual Maturity ◽  
Management And Conservation

Some biological parameters of Salmostoma bacaila – including sex ratio, length-frequency distributions (LFDs), size at sexual maturity, spawning season, length-weight relationships (LWRs) and condition factor – were studied. Samples were collected seasonally during June 2017 to May 2018 from a tributary of the Payra River. The overall sex ratio was significantly different from the expected value of 1:1 (p < 0.001), in favour of male specimens. Females were significantly larger than males. Size at sexual maturity was estimated at 7.6~7.7 cm total length. Seasonal variations in the gonadosomatic index (GSI) indicate that the main spawning season is from spring to summer. The LWRs showed negative allometric growth in both sexes, but with clear seasonal variation. Fulton’s condition factor varied in both sexes and was attributed to variations in GSI with maturity. The fin¬dings of this study will be helpful for management and conservation of S. bacaila populations.

Chamelea gallina reproductive biology and Minimum Conservation Reference Size: implications for fishery management in the Adriatic Sea

BMC Zoology ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Giada Bargione ◽  
Fortunata Donato ◽  
Giulio Barone ◽  
Massimo Virgili ◽  
Pierluigi Penna ◽  
...  
Keyword(s):  
Sexual Maturity ◽  
Adriatic Sea ◽  
Seawater Temperature ◽  
Reproductive Capacity ◽  
Great Effort ◽  
Important Species ◽  
Spawning Period ◽  
The Past ◽  
Chamelea Gallina ◽  
Size At Sexual Maturity

Abstract Background The striped venus clam Chamelea gallina is an economically important species in Adriatic Sea fisheries. The use of hydraulic dredging for its catch has a long history in Italy and its management faced several stages of development in the last 40 years. A great effort has been made in the past two decades to move from poorly or weakly managed fisheries to a well-structured co-management system to improve the sustainability of this fishery. However, a prerequisite for appropriate resource management is a sound knowledge of the biology and reproductive strategy of the species. Results We investigated three major biological features– the gametogenic cycle, size at sexual maturity and partial fecundity – by microscopic, histological and video analysis techniques. We demonstrated that its breeding season is driven by rises in seawater temperature and chlorophyll-a concentration and that its spawning period lasted from March to September. Size at sexual maturity was reached very early in the life cycle. As regards partial fecundity – the number of mature oocytes potentially released by females with ripe gonads in a single release event – varied in relation to size. Nevertheless, the reduction on the Minimum Conservation Reference Size (MCRS) from 25 to 22 mm (Delegated Regulation (EU) 2020/2237) lead to a 40% reduction in the number of emitted eggs. Conclusions We suggest that the ability of Adriatic clam stocks to withstand the strong fishing pressure of the past 40 years and the present one is due to their high reproductive potential and multiple spawning events combined with the effect of management measures (closed areas/seasons, quota, MCRS) and technical constraints on the gear and the sieve on board. Moreover, since the reduced MCRS for Venus shells is still larger than the size at maturity, it will probably not be detrimental to the reproductive capacity of the stock.

Changes in female lobster (Homarus americanus) size at maturity and implications for the lobster resource in Long Island Sound, Connecticut

2001 ◽  
Vol 52 (8) ◽  
pp. 1283 ◽  
Author(s):  
Donald F. Landers Jr ◽  
Milan Keser ◽  
Saul B. Saila
Keyword(s):  
Sexual Maturity ◽  
Egg Production ◽  
Long Island ◽  
Homarus Americanus ◽  
Long Island Sound ◽  
Female Size ◽  
Size At Maturity ◽  
Size At Sexual Maturity ◽  
Average Size ◽  
Island Sound

Population theory predicts that, under conditions of high age/size-specific mortality rates, individuals in highly exploited populations increase their fitness by decreasing size at sexual maturity, relative to less exploited populations. The benefit of early reproductive maturation is that individuals have a higher probability of surviving to maturity and contributing progeny to maintain the population. Empirical evidence, based on morphometric data from nearly 60 000 female lobsters collected since 1981, suggests that size at sexual maturity of female lobsters in Long Island Sound (USA) has recently decreased. Our findings were supported by decreases in average size and increases in abundance of egg-bearing females over the past two decades. Changes in female size at maturity and subsequent higher egg production may also help to explain the recent increase in lobster recruitment and landings. It is unclear whether these changes were caused by density-dependent factors related to the high exploitation of the species, by natural environmental factors (e.g. higher seawater temperatures), or a combination of the two.

scholarly journals Life-history strategies associated to reproduction of three Hyphessobrycon species (Characidae) in lentic environments of upper Paraná River basin

2013 ◽  
Vol 25 (4) ◽  
pp. 398-405 ◽  
Author(s):  
Cristina da Silva Gonçalves ◽  
Ursulla Pereira Souza ◽  
Fabio Cop Ferreira ◽  
Alexandre Peressin ◽  
Francisco Manoel de Souza Braga
Keyword(s):  
Life History ◽  
River Basin ◽  
Sexual Maturity ◽  
Life History Strategies ◽  
Oxbow Lakes ◽  
Parana River ◽  
Three Samples ◽  
Size At Sexual Maturity ◽  
Upper Paraná River ◽  
Upper Paraná River Basin

AIM: Life-history strategies in fish include essential parameters related to offspring survivorship, fecundity and time of reproduction, which represent adaptive traits that enable a species to deal with spatial and temporal variability of abiotic conditions. This study aimed to compare reproductive traits associated to life-history theory for three Hyphessobrycon species from two lentic environments (four natural oxbow lakes and a man-made reservoir) of Mogi Guaçu River, upper Paraná River basin. METHODS: Specimens were collected with four minnow traps between August 2005 and July 2006 to cover dry and wet seasons (three samples in each season, and three samples in each environment). RESULTS: Reproductive strategy of H. bifasciatus and H. eques, which predominated in the oxbow lakes, differed from H. anisitsi in the reservoir. Hyphessobrycon bifasciatus and H. eques were single spawners with lower fecundity and size at sexual maturity, but invested more in number of eggs per body gram, while H. anisitsi was a multiple spawner species with higher fecundity, larger size at sexual maturity and body size. CONCLUSIONS: In seasonal environments, single spawners are synchronized with the floods to maximize juvenile survivorship, while reservoirs harbors multiple spawners’ fish due to the reduced fluctuation between high and low floods resulting from dam operation. Therefore, the seasonal condition in the oxbow lakes due to the flood pulse favored single spawners’ tactic, as showed by H. bifasciatus and H. eques. In contrast, the multiple spawning of H. anisitsi seems to be related to the more stable environmental condition throughout the year provided by the dam. Life-histories reported herein to Hyphessobrycon species must be common to other characid fishes inhabiting similar environments.

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