Noor Us Saher

Population genetics of the fiddler crab Uca sindensis (Alcock, 1900) (Crustacea: Brachyura: Ocypodidae) from the Arabian Sea

BackgroundThe fiddler crab Uca sindensis (Alcock, 1900) (Crustacea: Brachyura: Ocypodidae) is distributed in the northern coasts of the Arabian Sea (Pakistan, Iran, Iraq, and Kuwait). Its typical habitat is on high intertidal areas with higher salinity, which might restrict its distribution, especially within the Persian Gulf. The purpose of the present phylogeographic study is to understand whether the Strait of Hormuz acts as a barrier to the gene flow of this species.ResultsThe genetic analyses of the mitochondrial 16S rRNA, cytochrome oxidase subunit I (COI), and control region (CR) of specimens from various localities showed that there was no genetic differentiation between the populations inside and outside of the Persian Gulf.ConclusionsWe conclude that the narrow Strait of Hormuz does not form a barrier for the larval dispersal in this species. Its restricted distribution in the northern Arabian Sea may instead be associated with its preference for higher salinity sediments present in the coasts of this region.

Comparison of heavy metal contamination during the last decade along the coastal sediment of Pakistan: Multiple pollution indices approach.

Heavy metals concentrations (Fe, Cu, Zn, Ni, Cr, Co, Pb, and Cd) were scrutinized during two monitoring years (2001 and 2011) in the coastal sediment of Pakistan. The status of metal contamination in coastal sediment was interpreted using sediment quality guidelines, and single and combined metal pollution indices. Ni, Cr, and Cd were recognized for their significant (p<0.05) intensification in the sediment during the last decade. Sediment quality guidelines recognized the frequent adverse biological effect of Ni and the occasional adverse biological effect of Cu, Cr, Pb and Cd. Single metal pollution indices (Igeo, EF, CF, and ER) revealed that sediment pollution is predominantly caused by Pb and Cd. Low to moderate contamination was appraised along the coast by multi-metal pollution indices (CD and PERI). Correlation study specifies that heavy metals were presented diverse affiliations and carriers for distribution in the sediment during the last decade.

Density, distribution and population structure of Opusia indica (Ocypodoidae: Camptandriidae) in a coastal mangrove creek in Pakistan

The density, distribution and population structure of Opusia indica were studied through transects method. Two transects were delimited in a mangrove area of Korangi creek (24°79′ N/67°20′ E). On each transect, three 0.25 m2 quadrats were sampled at three tidal levels on a monthly basis during low tide. A total of 1919 crabs were obtained, of which 775 were males, 945 were non-ovigerous females and 199 were ovigerous females. Density of crabs varied between 198 m−2 to 798 m−2. The density and size distribution showed significant difference from low tide level to high tide level and were positively correlated with the percent moisture, percent organic matter and sediment structure. Based on carapace width (CW) males were significantly larger than the females indicating sexual dimorphism. The monthly size frequency distribution of crabs showed recruitment of juvenile crabs (< than 4 mm) nearly throughout the year except in few months. The monthly sex ratio deviated from 1:1 throughout the year, with female bias (χ2 = 31.633, P = 0.001 and df =11). Breeding was seasonal with peaks in SW monsoon. Size at sexual maturity based on smallest ovigerous female was CW = 4.0 mm. The average number of eggs per female were 2066 ± 479 (n = 25). Positive linear relationship was observed between the size of the female crabs and the egg numbers (r2 = 0.554).

On a new record of the genus Uca (Decapoda, Brachyura, Ocypodidae) found along the coast of Pakistan

This is the first record from Pakistan of Uca iranica Pretzmann, 1971, a species that occurs in mangrove areas. U. iranica now appears to be one of the frequently and abundantly distributed Uca species on the coast of Pakistan. This species was previously reported from the Gulf of Oman and the Persian Gulf. To date, four species of Uca known from Pakistan have been confirmed.

Re description and molecular identification of Thalamita danae (Stimpson 1858) (Decapoda: Brachyura: Portunidae) based on fresh material from the coastal waters, Pakistan

Abstract Thalamita danae (Stimpson1858), re-described as a new report, based on an integrative taxonomy approach combining 16S rRNA partial sequence of mitochondrial DNA and morphological analyses was used for the accurate identification of specimens. The morphological and molecular analysis provides the confirm evidence of T. danae in coastal waters of Pakistan. Results were confirmed by amplification of partial sequences of 16S rRNA mt-DNA gene and the sequence was searched for similarity using BLASTn (Basic Local Alignment Tool), the result showed 97% sequence similarity with partial sequences of T. danae Stimpson, 1858 as obtained from gene bank. The attained sequence was submitted to gene bank after confirmation of genetic and morphological similarity. High sequence similarity with accession no: FJ152165.1 indicated, that misidentification of species does not occur.

Studies on Isozyme Variations and Morphometric Relationship among three Populations of Austruca sindensis (Alcock 1900) from Pakistan

The isozyme variability and morphometric analysis were examined in three populations of the fiddler crab, Austruca sindensis. The crab samples were collected from the three populations of A. sindensis (Sandspit, Sonari, and Sonmiani) along the coast of Pakistan. Three different enzymes, Catalase (CAT), Carbonate dehydratase (CD), Amylase (Amy) and a general protein pattern were investigated. Two isozymes were identified to be useful for the populations differentiation of A. sindensis along the coast of Pakistan. POPGENE software was used for the analysis of banding pattern, polymorphic loci, allelic frequency, heterozygosity and genetic distance of three populations of A. sindensis; while, Minitab and MS-Excel was used for the analysis of morphometric analysis. Four polymorphic loci, CAT-I, CAT-II, CD-I and CD-II were interpretable in muscle with Polyacrylamide Gel Electrophoresis (PAGE), the allele frequency differs significantly, detected in population of the Sonmiani Bay as compared with Sonari and Sandspit. The morphometric analysis showed low level of variability among the three studied populations when total 8 selected morphometric traits were analyzed (wet weight (WW), carapace length (CL), carapace width (CW), abdominal length (AL), abdominal width (AW), enlarged chela length (EL), enlarged chela width (EW), pleopode length (PL)). Multiple statistical approaches applied; regression analysis, ANOVA and Discriminant function analysis (DFA). Among all the statistical analysis used total three traits, showed significant variations among three populations (CW, EL and AL). The result of this study indicated that not only the morphological difference reflects the environmental conditions of habitat, but also the biochemical variations can be considered as the indicator of specific population dispersal.

Burrow Morphology of Genus Ocypode (Brachyura: Decapoda: Ocypodidae) Along the Coast of Karachi

Burrow morphology of Ocypode rotundata and O. ceratophthalma was studied on the sandy beach of Karachi with the aim of identifying their significance and relationship to the shore environment. The small sized burrows found at low tide level and large sized burrows found at the high tide level up to dry or splash zone. The burrow count during the winter season was lower as compared summer season. Only single burrow opening was observed in O. rotundata and O. ceratophthalma oriented towards the sea. The burrow depth was between 460 to 1300 mm and 490 to 760 mm in O. rotundata and O. ceratophthalma respectively. Strong correlation (r2=81.2 and 89.2%) was observed between carapace length and burrow diameter of the O. rotundata and O. ceratophthalma respectively. For the grain size analysis, maximum amount of grain resulted with fine sand 57.04% (2.5Φ, 3.0Φ). For anthropogenic analysis, data showed no any significant difference (P value =0.128 and 0.671) from two sites but number of burrow counts decreases as the number of human activity increasing day by day at the selected beaches.

Temporal variations of mesozooplankton abundance and biomass in the mangrove creek area along the Karachi coast, Pakistan

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, pH, 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.