scholarly journals Habitat-based spatial and temporal variability in life history characteristics of female common dolphins Delphinus delphis in the eastern tropical Pacific

2006 ◽  
Vol 318 ◽  
pp. 277-286 ◽  
Author(s):  
K Danil ◽  
SJ Chivers
Keyword(s):  
Life History ◽  
Temporal Variability ◽  
Tropical Pacific ◽  
Spatial And Temporal Variability ◽  
Eastern Tropical Pacific ◽  
Delphinus Delphis ◽  
Life History Characteristics ◽  
Common Dolphins

Growth and reproduction of female short-beaked common dolphins, Delphinus delphis, in the eastern tropical Pacific

2007 ◽  
Vol 85 (1) ◽  
pp. 108-121 ◽  
Author(s):  
K. Danil ◽  
S.J. Chivers
Keyword(s):  
Life History ◽  
Sexual Maturity ◽  
Large Scale ◽  
Life History Strategy ◽  
Maximum Size ◽  
Tropical Pacific ◽  
Lactation Period ◽  
Eastern Tropical Pacific ◽  
Delphinus Delphis ◽  
Common Dolphins

We characterize the life-history strategy of female short-beaked common dolphins ( Delphinus delphis L., 1758) inhabiting the eastern tropical Pacific by estimating several growth and reproductive parameters. Reproductive condition (n = 700) and age (n = 405) were determined for animals sampled from those incidentally killed in the yellowfin tuna ( Thunnus albacares (Bonnaterre, 1788)) purse-seine fishery between 1975 and 1993. Females averaged 160.4 cm at age 2 years, 186.5 cm at attainment of sexual maturity, and 197.2 cm at asymptotic length. The estimated age at attainment of sexual maturity was 7.9 years and the oldest animal in the study was 25 years. Calving occurred throughout the year, with females producing a calf approximately every 2.1 years after a gestation period of approximately 11.4 months, an average lactation period of 16.5 months, and an average resting period of 2.8 months. A relatively high percentage (30.4%) of lactating females were simultaneously pregnant, which effectively shortens the average calving interval. No clear evidence of senescence was found. Estimated lengths at birth, 2 years of age, attainment of sexual maturity, and maximum size were greater than those reported for the temperate North Pacific population, indicating that large-scale geographic variation in life history occurs for this species, which likely reflects population-specific adaptations to the tropical and temperate habitats that they occupy.

scholarly journals Seasonal and interannual variations in the distributions of tuna-associated dolphins in the eastern tropical Pacific Ocean

2019 ◽  
Vol 20 (1) ◽  
pp. 67-79
Author(s):  
Paul C. Fielder ◽  
Cleridy E. Lennert-Cody
Keyword(s):  
Pacific Ocean ◽  
Tropical Pacific ◽  
La Niña ◽  
Niche Separation ◽  
Common Dolphin ◽  
Cold Tongue ◽  
Tropical Pacific Ocean ◽  
Eastern Tropical Pacific ◽  
La Nina ◽  
Common Dolphins

Seasonal and interannual (El Niño–La Niña) variations in dolphin distributions in the eastern tropical Pacific Ocean have not been quantified, inspite of an extensive research vessel database. Fisheries observer data from the yellowfin tuna purse-seine fishery, collected year-round from 1986through 2015, were used to construct a binned spatiotemporal dataset of the presence/absence of spotted, spinner and common dolphin schools bymonth and 1° area. Distribution patterns were predicted from generalised additive logistic regression models applied to the binned data, with dynamicpredictors of surface temperature and salinity, thermocline depth and a stratification index. The dolphin taxa, especially common dolphins, showsome niche separation in relation to these variables. Predicted distributions for each taxon showed seasonal and interannual differences. Spottedand spinner dolphins responded to changes in the position and size of the eastern Pacific warm pool and avoided the equatorial cold tongue inSeptember–October and during La Niña. Common dolphins responded to seasonal and interannual changes in the Costa Rica Dome, the cold tongue,and the coastal upwelling habitat along Baja California, Peru and Ecuador. These predicted temporal variations are consistent with changes inpreferred habitat driven by environmental variability.

Seed-bank dynamics of Eleocharis: can spatial and temporal variability explain habitat segregation?

2004 ◽  
Vol 52 (1) ◽  
pp. 119 ◽  
Author(s):  
Dorothy M. Bell ◽  
Peter J. Clarke
Keyword(s):  
Life History ◽  
Seed Bank ◽  
Temporal Variability ◽  
Seedling Recruitment ◽  
Seedling Survival ◽  
Soil Seed Bank ◽  
Decay Rates ◽  
Habitat Partitioning ◽  
Spatial And Temporal Variability ◽  
Seed Bank Dynamics

Four Eleocharis species exhibit habitat partitioning in both extant vegetation and in the soil seed bank of upland temporary wetlands on the Northern Tablelands of New South Wales. Explanations for this partitioning were sought in seed-bank dynamics at three shore levels in two wetlands. Habitat partitioning (zonation) was explained in part by seedling recruitment but not by either persistence of seeds in the soil or by dormancy patterns. All four species recruited at wetland edges but only the deepwater species, Eleocharis sphacelata, recruited in deeper water. Viability of buried seeds was consistently high and species had very low decay rates and half-lives greater than 50 years. Two types of dormancy patterns with burial were shown. Most seeds of Eleocharis sphacelata and E. pusilla were non-dormant after a 3-month burial, whereas for E. acuta and E. dietrichiana seed germination percentages gradually increased over a number of years. These two dormancy patterns may contribute to coexistence, since coexistence is enhanced by a long-lived resistant phase in the life history of species and by temporal variability in germination. There were also spatial inconsistencies in patterns of dormant fractions. Burial in the deeper zones of the marsh-like Billybung Lagoon had an inhibitory effect both on germinability and on germination rates of E. acuta and E. dietrichiana seeds. All but E. acuta showed some degree of seasonal dormancy, but this pattern was also not consistent in space. Explanations for zonation should concentrate on other life-history phases, such as dispersal and seedling survival.

Response of Corn Grain Yield to Spatial and Temporal Variability in Emergence

Crop Science ◽  
2004 ◽  
Vol 44 (3) ◽  
pp. 847 ◽  
Author(s):  
Weidong Liu ◽  
Matthijs Tollenaar ◽  
Greg Stewart ◽  
William Deen
Keyword(s):  
Grain Yield ◽  
Temporal Variability ◽  
Spatial And Temporal Variability ◽  
Corn Grain ◽  
Corn Grain Yield
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