| 2 | Zonal distribution and population biology of Ilyoplax frater (Brachyura:Ocypodoidea:Dotillidae) in a coastal mudflat of Pakistan显示文摘Zonal distribution and population biology of Ilyoplax frater were studied in a mangrove mudflat area of Pakistan.The crabs were collected from Korangi creek through transect and quadrat method from low tide level to high tide level. Twotransects were delimited in a mangrove area of Korangi creek (24°79'N/ 67°20'E). On each transect, three 0.25 m quadrats weresampled at three tidal levels on a monthly basis during low tide periods from March 2001 to February 2002. A total of 1124 crabswere obtained, of which 482 were males and 642 were females. Density of crabs varied between 0 and 90 /m'. The density andsize distribution varied and showed significant differences from low to high tide level, and were positively correlated with thepercent moisture, percent organic matter and sediment grain size. The carapace width (CW) ranged from 2.5 to 11.5 mm for maleand 2.5 to 11.0 mm for female and was not significantly different. The overall sex ratio did not differ significantly from the expected1:1 throughout the year in small crabs but was significantly different in adult crabs (x^2= 49.73) with more male crabs. Sizefrequency distribution showed recruitment of juvenile crabs (< 4 mm) nearly throughout the year except during June and July.Presence of ovigerous females in all months with seasonal peaks in September, October, December and May indicates seasonalcontinuous breeding. Weight of egg mass increases with weight of ovigerous females and show positive linear relationship. Theestimated mean diameter of egg was 2.83±0.25μm, and the average number of eggs was | Noor Us SAHER Naureen Aziz QURESHI | 2010 | Current Zoology2010，56，2： | 0 |
| 3 | Temporal variations of mesozooplankton abundance and biomass in the mangrove creek area along the Karachi coast, Pakistan显示文摘The temporal variations of mesozooplankton abundance and biomass(1-Volumetric method by settling volume and displacement volume and 2- Gravimetric method through wet weight, dry weight and ash-free dry weight) with relation to environmental parameters were studied in the mangrove creek area of Karachi coast, Pakistan. The data of mesozooplankton samples along with environmental parameters(temperature, salinity, p H, etc.) were collected during January 1998 to December 1998 from two creek stations. The abundance of mesozooplankton also exhibited seasonal trends at both stations. At Sta. S2, the highest and lowest abundance values were observed during post-monsoon and southwest monsoon respectively whereas, at Sta. S1, a clear trend of high abundance in pre-monsoon to low abundance in southwest monsoon was observed. Mesozooplankton abundance was also positively correlated with settling volume, displacement volume, wet weight and dry weight. The highest biomass value was observed in the northeast monsoon and pre-monsoon periods. The results of the canonical analysis of the output from the discriminate function was tested. Out of fifteen variables, only one was significantly different in single character ratios dry weight/ash free-dry weight(F3,23=4.78, P<0.005). The mesozooplankton community was collectively composed of 28 taxa. Among these groups, copepoda(66.3%), gastropod larvae(9.94%), evadne(4.60%), zoea(3.60%), cypris nauplii(2.56%), lemellibranch larvae(1.87%), chaetognaths(1.81%), ostracods(1.73%), lucifer(1.15%) and barnacles nauplii(1.35%) contributed the most to the similarities within Sta. S1, while copepoda(74.68%), cypris nauplii(5.29%), gastropods(4.87%), barnacles nauplii(4.81%), evadne(1.72%), zoea(1.53%) and caridean larvae(1.18%) at Sta. S2. The remaining mesozooplanktonic group were accounted for less than 5% and 6% at Sta. S1 and Sta. S2 respectively, of the total organisms. Similarity percentage(SIMPER) analysis revealed that copepoda, gastropod larvae and cyprus nauplii contributed most of the similarities within Sta. S2 along Sta. S1. | Farah Naz Naureen Aziz Qureshi Noor Us Saher | 2014 | Acta Oceanologica Sinica2014，33，12： | 0 |
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