scholarly journals Population Aspects of Graceful Mojarra Eucinostomus gracilis (Perciformes: Gerreidae) in a Coastal Lagoon in the Tropical Eastern Pacific

2020 ◽  
Vol 20 (12) ◽  
pp. 845-855
Author(s):  
Carlos Rabago-Quiroz ◽  
Jesús Padilla-Serrato ◽  
Juana López-Martínez ◽  
Juan García-Borbón ◽  
Joaquin D. Magaña
Keyword(s):  
Sex Ratio ◽  
Spatial Variation ◽  
Coastal Lagoon ◽  
Size At Maturity ◽  
Tropical Eastern Pacific ◽  
Lagoon System ◽  
Moderate Growth ◽  
Logistic Method ◽  
Swept Area ◽  
Lagoon Systems

Graceful mojarra (Eucinostomus gracilis) is an important component of the ichthyic fauna of lagoon systems but knowledge of its population aspects is scarce. Monthly samples in the Magdalena-Almejas Lagoon system (March-August, 2014-2017) were obtained with a trawling net. Abundance was estimated using the swept area method and its spatial variation; and the maturity size was determined using the logistic method. The sex ratio for mature and immature populations, and their length-weight relationship were estimated; FISAT was used to estimate the growth and recruitment parameters. Abundance ranged from 0.6 to 203 ind-Ha-1 with changes for each lagoon system areas and among years. Size at maturity (L50) was 132 mm in total length (TL) for the population, 129 mm TL females, and 135 mm TL males. Considering the population of the total organisms, L50 indicated that 18% were adults and 82% were juveniles. Juvenile dominance indicated that this lagoon system is used for grow-out. The smaller ratio of adult organisms does not allow asserting assertion that the priority of the area is for reproduction. E. gracilis showed moderate growth (K = 0.56 year-1) with longevity of 5.4 years and asymptotic length of L∞ = 195 mm.

A Trophic Model for a Periodically Closed Coastal Lagoon System in the Southern Mexican Pacific

Wetlands ◽  
2021 ◽  
Vol 41 (5) ◽  
Author(s):  
Jesús M. López-Vila ◽  
Juan J. Schmitter-Soto ◽  
Ernesto Velázquez-Velázquez
Keyword(s):  
Coastal Lagoon ◽  
Mexican Pacific ◽  
Lagoon System

Size At Maturity and Sex Ratio of Arcitalitrus Dorrieni (Hunt, 1925) (Amphipoda, Talitridae) At Two Sites in County Galway, Ireland

Crustaceana ◽  
1997 ◽  
Vol 70 (6) ◽  
pp. 676-693
Author(s):  
Thomas Bolger ◽  
Rory P. O'Hanlon
Keyword(s):  
Sex Ratio ◽  
Northern Hemisphere ◽  
General Pattern ◽  
Breeding Period ◽  
Amphipod Species ◽  
Size At Maturity ◽  
Anthropogenic Dispersal ◽  
Deciduous Woodland

AbstractAnthropogenic dispersal has led to the introduction of several terrestrial amphipod species to the northern hemisphere. One such species, Arcitalitrus dorrieni (Hunt, 1925), a native of Australasia, is now found in several woodland sites in Ireland and Britain. Aspects of the biology of A. dorrieni were investigated in County Galway over a period of two years and compared between a "typical" mixed deciduous woodland habitat and a more "atypical" coniferous woodland habitat. At both sites, statistically significant differences were found between summer (Aug.-Sep.) size at maturity and winter (Jan.-Apr.) size at maturity, i.e., females were mature at smaller sizes in summer than in winter. Between-site comparisons of August-September data for both years showed that females were mature at a significantly smaller size at the mixed deciduous woodland site. A sex ratio biased in favour of females was recorded on all but one sampling date at each site, though on some dates this bias was not significant. The change in cohort sex ratio at both sites was quite distinct and exhibited the same general pattern. During the recruitment of each cohort, the ratio was biased towards males. As the cohort increased in length, however, the ratio changed to a bias in favour of females, so that by the time a particular cohort entered its breeding period the following year, it was biased firmly in favour of females. Possible reasons for the observed patterns are discussed.

scholarly journals Change in size-at-maturity of the yellownose skate Dipturus chilensis (Guichenot, 1848) (Elasmobranchii: Rajidae) in the SW Atlantic

2008 ◽  
Vol 6 (2) ◽  
pp. 223-230 ◽  
Author(s):  
Laura Paesch ◽  
María C. Oddone
Keyword(s):  
Sex Ratio ◽  
Size At Maturity ◽  
Egg Capsules ◽  
Total Length ◽  
Sw Atlantic

A total of 3518 specimens (1607 males, 1911 females) of Dipturus chilensis were sampled. Males ranged from 44.0 to 99.0 cm and females from 45.0 to 110.0 cm. Total length composition of the grouped catches differed significantly among sexes, with females being larger than males. The sex ratio favored the females. The total length at which 50% of the specimens were retained by the gear was 69.0 cm for the males and 73.0 cm for the females. A sub-sample of 124 specimens (48 males, 76 females) was analyzed for reproductive assessment. For the males, size at 50% maturity was estimated at 78.5 cm, while for the females this parameter was estimated at 81.4 cm. Preliminary observations on the description of the egg capsules are also provided.

Sex ratio, spawning season and size at maturity of red bandfish in the western Aegean Sea

1996 ◽  
Vol 49 (4) ◽  
pp. 561-572 ◽  
Author(s):  
K. I. Stergiou ◽  
P. Economidis ◽  
A. Sinis
Keyword(s):  
Sex Ratio ◽  
Aegean Sea ◽  
Spawning Season ◽  
Size At Maturity
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