Population dynamics of Stenothoe valida Dana, 1852 (Amphipoda, Stenothoidae) at Cheongsapo beach of Busan, Republic of Korea

Crustaceana ◽  
2021 ◽  
Vol 94 (4) ◽  
pp. 413-429
Author(s):  
Ye Ji Lee ◽  
Won Gyu Park

Abstract The population dynamics of Stenothoe valida Dana, 1852 were studied at Cheongsapo beach of Busan, Republic of Korea, from March 2019 to March 2020. Sampling was conducted once a month at low tide during spring tides. Specimens were grouped by the cephalic length at 0.025 mm intervals, and classified into four categories: females, ovigerous females, males and juveniles. The sex ratio, defined as females : total males + females, exceeded 0.5 during most of the study period. Brood size was significantly coupled with ovigerous female size. Two to four cohorts appeared at each study period. New cohorts occurred at almost every sampling except in the samples Jun-2, and Nov-2. Life span was estimated at 1-2 months. The juvenile ratio, the ratio of ovigerous females, and the recruitment rate estimated by FiSAT were commonly high in summer and winter. The life history of S. valida was not coupled with water temperature, but had a strong seasonal pattern.

Author(s):  
M. B. Jones ◽  
G. D. Wigham

A population of the supralittoral Orchestia gammarellus (Pallas) (Amphipoda: Talitridae), living in a percolating filter of a sewage treatment works has been studied over 12 months. The population showed a seasonal pattern of occurrence, few animals being collected during the winter. The sex ratio was biased significantly to females except during the breeding season when it did not deviate significantly from 1:1. Ovigerous females, never collected in high numbers (1–14 per month), were found from April to August, with peak occurrence in May/June. Juveniles were present throughout the year, but peak recruitment occurred in summer, following the period of reproduction by females. The smallest ovigerous female had a body length of 12.6 mm and the largest measured 20.0 mm. Egg numbers (5–31 per brood) increased with increasing female size and egg volume more than doubled during embryonic development. These findings are discussed in relation to the possible methods of colonization of this unique habitat and the influence of sewage on crustacean life-history traits.


2020 ◽  
Vol 117 (30) ◽  
pp. 18119-18126 ◽  
Author(s):  
Line S. Cordes ◽  
Daniel T. Blumstein ◽  
Kenneth B. Armitage ◽  
Paul J. CaraDonna ◽  
Dylan Z. Childs ◽  
...  

Seasonal environmental conditions shape the behavior and life history of virtually all organisms. Climate change is modifying these seasonal environmental conditions, which threatens to disrupt population dynamics. It is conceivable that climatic changes may be beneficial in one season but result in detrimental conditions in another because life-history strategies vary between these time periods. We analyzed the temporal trends in seasonal survival of yellow-bellied marmots (Marmota flaviventer) and explored the environmental drivers using a 40-y dataset from the Colorado Rocky Mountains (USA). Trends in survival revealed divergent seasonal patterns, which were similar across age-classes. Marmot survival declined during winter but generally increased during summer. Interestingly, different environmental factors appeared to drive survival trends across age-classes. Winter survival was largely driven by conditions during the preceding summer and the effect of continued climate change was likely to be mainly negative, whereas the likely outcome of continued climate change on summer survival was generally positive. This study illustrates that seasonal demographic responses need disentangling to accurately forecast the impacts of climate change on animal population dynamics.


2020 ◽  
Vol 52 (3) ◽  
Author(s):  
Bhandari Jyoti ◽  
Yasen Shali ◽  
Zhang Zehua ◽  
Yao Xiaoho ◽  
Deng Jiang ◽  
...  

1997 ◽  
Vol 48 (4) ◽  
pp. 361 ◽  
Author(s):  
Marty A. Hancock ◽  
Stuart E. Bunn

Aspects of the life history and population dynamics of Paratya australiensis were examined in headwater streams of the Conondale Range, south-eastern Queensland, particularly in relation to spatial and temporal variation in temperature and flow dynamics. Breeding period and population structure at nine sites in three subcatchments were examined during three years of monthly sampling using a non-destructive, photographic method. Breeding was restricted to the warmer months of late spring and summer. Peak abundances of ovigerous females and release of larvae occurred earlier at warmer, lower-altitude sites than at cooler, upper-altitude sites. This is consistent with the general trend for seasonal breeding in temperate and subtropical species of atyids, and perennial breeding in tropical species, and suggests that the summer breeding period of P. australiensis was strongly influenced by temperature. In subtropical, south-eastern Queensland, larvae were released just before and during the wet season. Although populations were quite resilient, disturbance from high-flow events also shaped the life history. Hydrology modified the breeding period by influencing overall abundance and recruitment success and by favouring the early release of larvae before peak flows. The reasonably well defined seasonal cycle and synchronized development appear to result from the combined effects of temperature and hydrology.


Author(s):  
Kenji Yoshino ◽  
Manato Nagayoshi ◽  
Masanori Sato ◽  
Toshiya Katano ◽  
Yuji Ito ◽  
...  

The life history of the Japanese sternaspid polychaeteSternaspis costatavon Marenzeller, 1879 was investigated in the inner part of Ariake Bay from May 2010 to May 2011, with additional sampling in July and September 2011. All the worms were measured by the width of the ventral shield (WS) as an indicator of body size, and their coelomic contents were also examined. Ovigerous females occurred throughout the year, except during October and March, with the highest ovigerous rate (number of ovigerous females/number of adults with a WS larger than that of the smallest ovigerous female, i.e. 1.8 mm) noted in September (43.8% in 2010, 34.7% in 2011). The ovigerous rate was less than 10% in the other months, except in April 2011 (30%). Although the coelomic oocytes ranged from 90 to 160 μm in diameter, the diameters of most of the oocytes were 140–160 μm in September. The number of adults drastically decreased from September to October, suggesting that most of the adults died after spawning in the major reproductive period, although a small fraction of adults seemed to reproduce earlier or later. A cohort of recruits with an approximately 1.2 mm WS was identified in March and April. Most of the recruits grew to adult size in July–September, when many ovigerous females occurred. These results indicated that this species is fundamentally semelparous, with longevity around 1 year, and they mostly reproduce in September, with a few adults reproducing almost throughout the year.


1977 ◽  
Vol 34 (7) ◽  
pp. 942-953 ◽  
Author(s):  
Graham Bell ◽  
Paul Handford ◽  
Carl Dietz

The life history of the exploited lake whitefish (Coregonus clupeaformis) population of Lesser Slave Lake, Alberta, is described. Mean age is high, having increased under continued exploitation during the last 30 yr. A method of estimating the population age structure is described. The apparent annual rate of survival of adult fish has fluctuated markedly, but on average seems to lie in the interval 0.40–0.50; the annual rate of natural survival is estimated to be 0.53. Juveniles survive better than adults. Rate of survival during the 1st yr of life was estimated to be about 0.0002. Maturity was late, the median age at first reproduction being 6–61/2 yr. The regressions of fecundity on age and length are described; length now contributes almost all the attributable variance to maturity and fecundity. The sex ratio fluctuates in time; this is caused by the fluctuations in age structure, since sex ratio varies with age. The relationship between sex ratio and age is used to calculate the relative rates of survival of male and female fish.These data are used to construct a life table and to compute population parameters. It is inferred that the ability of the population to respond to exploitation has been eroded during the last 30 yr. In some respects, the life history of the Lesser Slave Lake stock appears to be unusual.After about 30 yr of large-amplitude oscillation the whitefish population collapsed in 1965. This does not seem to have been caused by chronic overfishing. In the first place, the rate of fishing mortality is no more than moderate. Secondly, a multiple regression equation describing whitefish catch in 48 other Alberta lakes in which there has been no overall decline in catch successfully predicts the observed mean catch at Lesser Slave Lake. The oscillations in catch are claimed to reflect a limit cycle in the abundance of the whitefish, driven by a lagged relationship between a predator (the fishermen) and its prey (the whitefish). Whether or not this cycle was deterministically stable, such behavior will inevitably put the population in risk of extinction during troughs in the cycle. We suggest that current management policies may encourage the destabilization of whitefish populations, and we propose a remedy. Key words: population dynamics, population regulation, life history, exploitation, survival, fecundity, Coregonus clupeaformis


Author(s):  
Carlos Litulo

This study aimed to assess the population biology and reproduction of the fiddler crab Uca chlorophthalmus at its limit of geographical distribution, Saco da Inhaca mangrove, southern Mozambique. Monthly samples were conducted at low tide periods between January and December 2003. The size distributions showed uni- and bimodal patterns, with males reaching larger sizes than ovigerous and non-ovigerous females. Females were slightly more abundant than males, but the overall sex ratio (1:1.01) did not differ significantly from 1:1. Uca chlorophthalmus displays continuous reproductive patterns with peaks of breeding in March and December. Moreover, linear correlations revealed that breeding in this crab is controlled by both temperature and rainfall. Similarly, juvenile recruitment was constant, but was more intense in winter (May–July). Brood size was positively associated with female size. Timing of the observed breeding pattern in the study area may enhance reproductive output and recruitment of the species.


Sign in / Sign up

Export Citation Format

Share Document