Diversity of Green Seaweeds along the Coast of Karachi

The seasonal diversity and species richness of marine benthic green algae or seaweeds belonging to the phylum Chlorophyta found at Karachi coast were studied in present study. At Karachi coast the green seaweeds occupy a large area and show great variation in their types and species composition. Total 48 green species of seaweeds belong to 9 genera 7 families 6 orders and 2 classes were collected from intertidal areas of Karachi coast (Buleji, Manora, Hawks Bay, Sandspit, Korangi Creek, Cape Monze, Paradise Point, Pacha and Rehri) during January 2009 to December 2009. Total 500 individuals examined, representing 9 genera i.e., Enteromorpha, Ulva, Chaetomorpha, Bryopsis, Codium, Caulerpa, Halimeda, Udotea, Valoniopsis. From the present observation, it’s clear that Buleji and Manora are the more productive sites as compared to other sites. There was great variation in number of species in different genus. All these forty-eight studied species were found attached and in epilithic condition. There is much monthly variation found in species richness at Karachi coast during study period. The present study showed that the high values of species richness and abundance of seaweeds were observed during winter season (December to February).

Some phycologist also made valuable contribution to the taxonomy of green algae of Karachi coast, e.g. Shameel (1978a) added to the list of Caulerpa one more species and presented an ecological account of all the 13 known species, other important investigation made by him were on the family Chaetophoraceae of Karachi coast (Shameel, 1978b). Other significant studies made on the taxonomy of green algae are: Nizamuddin and Begum (1973), Saifullah and Nizamuddin (1977), Zahid et al. (1983) and Amjad and Shameel (1993a;1993b). Apart from Karachi coast a few studies have also been made on the occurrence of algae including green seaweeds from the adjacent coast of Lasbela (Shameel, 1987;Shameel et al., 1989). A check list of marine planktonic and benthic algae of Pakistan has been published by Shameel and Tanaka (1992), which includes 27 genera and 90 species of green algae. Shameel and Shaukat (1992) also carried a taxometric study out three related species of Caulerpa. Recently a new classification of algae was proposed in which also marine Chlorophyta included (Shameel, 2001).
From the foregoing literature survey, it becomes apparent that these investigations are highly inadequate for the understanding of modern position of green seaweeds distribution and occurrence of the individual plant. Therefore, it is essentially needed to conduct a thorough and detailed study of the diversity and seasonal variation in distribution and habitat ecology of green seaweeds growing along the coast of Karachi.

Results and Discussion
A total of 48 species of seaweeds belong to 9 genera, 7 families, 6 orders and 2 classes were identified in the intertidal areas from different coast (Buleji, Cape Monze, Hawks Bay, Korangi Creek, Manora, Paradise Point, Pacha, Rehri and Sandspit) of Karachi during the study period January 2009 to December 2009 (Table 1). The present work showed that Pakistan coast especially Karachi coast has mostly rocky and sandy beaches that are rich in seaweeds species. Among 48 species thirty-nine species were collected from Buleji, thirty-four from Manora, ten from Paradise Point, six from Sandspit, three from each Korangi Creek, Hawks Bay and Cape Monze and two from each Pacha and Rehri sites ( Figure 1). The two coastal areas Buleji and Manora were found the more productive sites as compared to other sites.   Figure 2). There is no any new species is recorded in present investigation. All the studied species were already identified earlier in different times by different authors (Anand, 1940;Saifullah and Nizamuddin, 1977;Saifullah and Nizamuddin, 1992;Shameel and Shaukat, 1992;Amjad and Shameel, 1993a;Amjad and Shameel, 1993b;Aliya et al., 1994;Aliya and Shameel, 1996;Nizamuddin, 2001;Nizamuddin and Gul, 2005).  Table 2 and Figure 3. The total number of individuals were high in the month of January (114) and March (113) where as low in the month of September (4). The Enteromorpha (4.8%) is found at the coast of Karachi (Figure 4). There were six species of Enteromorpha (Enteromorpha intestinalis, Enteromorpha compressa, Enteromorpha flexuosa, Enteromorpha prolifera, Enteromorpha clathrata, Enteromorpha procera) collected in present study. Anand (1940) found five and Saifullah and Nizamuddin (1992) nine species of Enteromorpha. The most abundant species of Enteromorpha in present study were Enteromorpha intestinalis (37.5%) and Enteromorpha clathrata (33.3%) collected from Buleji, Korangi creek, Manora and Sandspit.  All forty-eight studied species were found attached and in epilithic condition. It is also noted that Caulerpa and Chaetomorpha species were occurred at soft substratum. From the results of present study, it is observed that species collected from different sites showed a significant variation in sites, habitat, structures and occurrence. The months of March (22) and January (18) were rich in seaweeds species and the months of May to July were poor in seaweeds species ( Figure 5). There is greater monthly variation found in species richness at Karachi coast ( Figure 6). The value of species richness (S) varied from 0.044-6.444. The highest value was recorded in the month of January (6.444), March (5.022) and December (4.311) and low in July (0.044). The positive significant correlation was found in between species of same genus (E. prolifera and E. intestinales (r 2 =0.580); Ulva scandinavian and Ulva rotanda (r 2 =0.817); Ulva compressa and Ulva rotanda (r 2 =0.757)) and different genus (Ulva rigida and E. intestinales (r 2 =0.758); Enteromorpha compressa and Chaetomorpha crassa (r 2 =0.744); Ulva rigida and Codium boergesenii (r 2 =0.674); Ulva fenestrata and Caulerpa manorensis (r 2 =0.960); Valoniopsis pachynema and H. tuna (r 2 =0.629)). The present study showed that the abundance of seaweeds and high values of species richness were observed during winter (December to February) season. From literature survey it is found that during winter season all hydrographic conditions (salinity, temperature pH and dissolve oxygen) were suitable for the growth of seaweeds (Qari and Siddiqui, 2005;Qari and Siddiqui, 2006). During the study epifloral species that were attached on studied green seaweeds were called Sargassum boveanum, Polysiphonia ferulacea and Gracilaria corticata. Beside the epifloral species some eplfaunal species are also found, attached on seaweed called Cantharus spiralis, Thais cannifera, Terebradussumieri, and Polychaetes worms.

Materials and Methods
Collection were made along the different beaches Buleji, Manora, Hawks Bay, Sandspit, Korangi Creek, Cape Monze, Paradise Point, Pacha and Rehri of Karachi coasts during the January 2009 to December 2009 at low tide. The sea at all studied coastal sites are very calm and quiet from October to March and very rough during the monsoon. Most of coastal sites are quite popular picnic and relaxation spots of Karachi.
Bulejiis located between Hawks Bay and Paradise Point, near fisher village. This is the triangular rocky plate Island. Boulders of various sizes are visible but mostly near the higher watermarks standing on a rocky base, pebbles, gravel, sand etc. Large number of seaweeds is found at Buleji comparatively other beaches of Karachi coastal areas. Manora is a small rocky and sandy island (2.5 km² ). The rocky shore of Manora has many verities of sea weeds. Hawks Bay is situated a couple of kilometers away from Sandspit. It is a sandy beach with natural beauty, spreading over a length of about 5 km and mostly used as picnic point. Hawks Bay is one of the few beaches in the world, where green marine turtles come to lay eggs. The site of Sandspit is situated south west of Karachi. It is also rocky and white sandy area where many sandy pits have found. Remarkable variety of marine algae and crabs are found here. It has an unusual rocky formation. During monsoon season high tides often cross over and enter into the backwater mangrove area, and refurbish the sediments with coastal sand.  (Abbas, 2006). In addition to industrial effluents, discharges from Bhains (buffalo) Colony cattle farms and domestic sewage from residential areas also ends up in the Korangi Creek system (Abbas et al., 2013). Cape Monze is relatively stable rocky beach with 10-12 meter high cliffs, located near the Hub River and Gadani Beach in Karachi. White sand is the most unique feature of the Cape Monze beach.
Paradise Point is covering distances of about 800 meters. The coast is open to sea front and the wave action is intense all along the coast. The rocky ledge of Paradise Point is mostly wave swept shore (Qari and Siddiqui, 2010). Pacha is the three thousand meters long sandy beach is located off Paradise Point. The beach is marked by the presence of 12-156 meters high cliffs. Effect of high wave action may be seen in the form of erosion. Rehri is one of the neighbor's hoods of Bin Qasim Port and supports a large community of fishermen. Its environment comprises of coastal area of Bin Qasim district which includes the union council of Rehri and Ibrahim Haidery besides the two Settlements of Chasma Goth and Lath Basti (Shahzad et al., 2009).
The sampling method (Chapman, 1964) was used for estimating the seaweeds quantum. Five quadrates of 1 m -2 sizes were randomly selected in the intertidal zone of each beach. All the seaweeds species were handpicked in each quadrate. In the laboratory seaweeds were washed with seawater followed by fresh water to remove adhering impurities, epiphytes and epifauna. Collected material were preserved and taxonomically investigated. The specimens were identified with the help of authentic available literatures (Anand, 1940;Smith, 1955;Silva, 1979;Shameel, 1992;Qari and Qasim, 1993;Nizamuddin, 2000;Gul et al., 2006).

Conclusion
On the basis of results obtained in the present investigation and those reported previously by Saifullah and Nizamuddin (1977;1992), Qari and Qasim (1988;, Aliya et al. (1994), Aliya and Shameel (1996) and Qari (2002), it may be concluded that occurrence and quantity of seaweeds species vary from time to time. The highest quantities of seaweeds were found in winter season i.e., winter period is best for cultivation of seaweeds growth. It is concluded that the present study will be most helpful for all researchers of marine science because the present study is presenting the diversity and abundance of seaweed species. The present study also showed that which month having maximum number of species for collection, harvesting and cultivation. In Pakistan it is necessary to harvest seaweeds on large scale because due to dearness all food items cannot easily purchase. So it is suggested that we should take advantage from our coastal resources i.e., luxuriant growth of seaweeds vegetation.
Author's contributions EK carried out the field and lab work. RQ designed, interpreted the data, made figures, statistical analysis, and drafted the manuscript. Both authors EK and RQ read and approved the final manuscript.