1 Introduction

Plankton is various small drifting plants, animals and microorganism that inhabit bodies of water. Plankton drives the “biological pump”, processes by which the ocean ecosystem transports carbon from the surface to the ocean’s depths. 

Coast of Baluchistan located on northern Arabian Sea comprising 70% shoreline, out of total coast of Pakistan. Sonmiani Beach is located in the Lasbela District of the Balochistan state of Pakistan. It is located in Sonmiani Bay. Planktons are diverse group of organisms that live in the water column and are incapable of swimming against water currents. Life in the water and specially in the sea has been broadly classified into three groups, viz., the plankton, the nekton and the benthos, which are floating, swimming and creeping organisms respectively. 

Among the all aquatic fauna and flora, planktons are one of the unique creatures. Victor Henson coined the term plankton in 1887 (Santhanam and srinivasan, 1994). Based on the nutrition, the plankton divided into plant plankton or Phytoplankton and animal plankton or zooplankton. In regard to the duration of planktonic life, the zooplankton may be grouped in holoplankton and meroplankton. The holoplankton comprise organisms which are planktonic throughout their life cycle while merplankton are remain planktonic only for a portion of their lifecycle (eggs and larvae of the aquatic animals).

Photosynthesis by the phytoplankton accounts for up to half of global primary production. They also provide the primary food source for the zooplankton, and together form the base of the oceanic food chain. Larger zooplankton, fish, and mammals depend on this plankton for their survival. Tying it all together, the bacterioplankton play an important role in the recycling and remineralization of materials and energy within the food chain.

Simpson's Diversity Index is a measure of diversity. In ecology, it is often used to quantify the biodiversity of a habitat. It considers the number of species present, as well as the abundance of each species.

Several papers have been published worldwide, focusing different mode of studies for understanding the taxonomy, biology, diversity, migration, ecology etc. of plankton. Ahlstrom et al., (1976) described the eggs and larvae of fishes and their role in systematic investigations in fisheries. Barnett and Beisner (2007), Barnett et al. (2007) explained the Zooplankton biodiversity and primary productivity relationship. In Pakistani waters, planktons were reported by Quddusi and Sultana (2008). From Balochistan no works have been done so far about the any aspect of planktons. The purpose of this study was to investigate the occurrence of plankton in Balochistan waters. Therefore, present study is undertaken which will provide the knowledge regarding plankton in balochistan waters. 

2 Materials and Methods

The planktons for this paper were collected from site of Somiani, Baluchistan. The site is located between 25^◦ 25ˊ 22̎ North latitudes, 66^◦35ˊ 44̎ East longitude. The plankton samples were collected randomly with the help of plankton net on the boat from three sites of shore. All sampling site were assigned a particular name i.e. 1. near the coast. 2. Near the mangroves area and 3. away from the coast. All specimens were preserving in 4% formaldehyde solution and keep in laboratory for their morphological studies. Morphological studies were carried out for each individual under the micropscope. Species were identified by the help of the following literatures: Gosner (1971), Santhanam and Srinivasan (1994) and Lalli and Parsons (1999). Planktons samples were grouped into nine namely; diatoms, dinoflagellates, copepod, lucifer, chaetognaths, Jellyfish, eggs, zoea larvae and last unidentified group “Others”. All identified sample were counted and further statistical analysis were conducted. Diversity index were calculated by Simpson diversity index equation as: 

D= Diversity Index

n = the total number of organisms of a particular species
N = the total number of organisms of all species

3 Result

58 specimens of zooplankton were collected from station 1, only six groups were present in this site. Figure 1 showed that Ceratium spp. were found in the highest percentage (38 %), while second highest group was copepods in 21% of total catch. A next dominant group was Eggs which was about 17%. Diatoms were found markedly very low in only 4 %. Zoea larvae, Chaetognatha and Jelly fish were not found from this site. Diversity index (D) of sample 1is D= 0.225. 

Figure 1 Percentage occurrence of planktons from station 1

From site 2 which was the near of the mangrove’s areas, total 50 plankton samples from 7 groups were collected (Figure 2). Two groups (Chaetoganatha and Jelly fish) were also totally absent from this site. 28% of copepods were found in the highest percentage of occurrence. Second highest occurring group was eggs which were about 26 % then Lucifer found in 16%. Only 2 % of diatoms were found. Diversity index (D) of sample 2 is D= 0.184.

Figure 2 Percentage occurrence of planktons from station 2

Out of 152 samples of planktons, 48 were collected from site 3 which was away from shore. Diatoms was absent from this site and other all eight groups were present (Figure 3). Copepods were found in highest percentage which is about 23% of total catch of this site. Meroplankton (Eggs and Zoea larvae) were found in same ratio which is 18 %.  Diversity index (D) of sample 3 is D= 0.144. 

Figure 3 Percentage occurrence of planktons from station 3

4 Discussion

Identification of plankton, yet not carried out from Baluchistan. Numerous studies have shown a strong relationship between larval fish survival and the timing and production of their food (i.e., plankton). Barnett and Beisner (2007) explained the timing and production of plankton are in turn directly dependent on water temperature and nutrient availability (which is indirectly controlled by temperature-driven circulation patterns). Changes in climate can affect the timing of the seasonal plankton blooms, with effects that pass up the food chain. Longer term changes in climate may even change the plankton species composition, changing the feeding environment of the larval fish. This may be concluded that plankton of Balochistan is diversifying.

In present investigation diatoms belonging to Phytoplankton and remaining group except “others” are zooplankton. Eggs and Zoea larvae are also called Meroplankton. In case of occurrence of plankton, results of present investigation show that copepods were the dominant group from all three sites about 24 % of total catch. Than Ceratium spp. and eggs were dominant about 20% of each. Diatom which are phytoplankton, were found in very low quantity i.e. 1.9 % of total catch during preset study. Chaetognath and jelly fish were also rare only one specimen was collected from station 3. The diversity of plankton from site three was relatively high as compare to other sites. Zooplanktons were abundant here but phytoplankton is not found.

This study aimed to approach it in Balochistan for first time to initiate the term of study for occurrence of plankton along the coast of Baluchistan. Coast of Baluchistan located on northern Arabian sea comprising 70% shoreline, out of total coast of Pakistan. Thus, there is an urgent need to examine the diversity of plankton inhabiting in Balochistan waters to understand the impact of plankton for future conservation and management. Moreover, the taxonomical determination is the first step of this study.

Author’s contributions

SR designed, conducted the experiments and writes the manuscript. AB, MR and AL collected the samples and identify and count the samples. All authors read and approved the final manuscript. 

References

Ahlstrom Elbert H., and Geoffrey M.H., 1976, Eggs and larvae of fishes and their role in systematic investigations in fisheries, Revue des Travaux de l'Institut des Pêches Maritimes, 40(3-4): 379-398

Barnett A.J., and Beisner B.E., 2007, Zooplankton biodiversity and primary productivity: explanations invoking resource abundance and distribution, Ecology, 88: 1675-1686

https://doi.org/10.1890/06-1056.1
PMid:17645014

Barnett A.J., Finlay K., and Beisner B.E., 2007, Functional diversity of crustacean zooplankton communities: towards a trait-based classification, Freshwater Biol., 52: 769-813

https://doi.org/10.1111/j.1365-2427.2007.01733.x

Ducklow H.W., and Steinberg D.K., 2001, Upper Ocean Carbon Oceanography, 14(2): 50-58

https://doi.org/10.5670/oceanog.2001.06

Diane K.S., and Capuzzo J.M., 1990, Predation on Protozoa: its importance to zooplankton, Journal of Plankton Research, 12(5): 891-908

https://doi.org/10.1093/plankt/12.5.891

Gosner K.L., 1971, Guide to identification of marine and esturarine invertebrate, Jhon Wiley and Sons, New York: 1-206

Harwood D.M., Nikolayev V.A., and Winter D.M., 2007, Cretaceous record of diatom evolution, radiation, and expansion, Paleontological Society Papers, 13: 33-35

https://doi.org/10.1017/S1089332600001455

Jawed M., 1973, Ammonia excretion by zooplankton and its significance to primary productivity during summer, Mar. Biol., 23: 115-120

https://doi.org/10.1007/BF00389168

Kazmi Q.B., and Sultana R., 2008, Carybdea marsupialis (Cnidaria, Cubomedusae) observed for the first time in Gwadar Bay waters (Arabian Sea), Marine Biodiversity Records, 1: 79-80

https://doi.org/10.1017/S1755267207008251

Lalli C.M., and Parsons T.R., 1999, Biological oceanography, an introduction, Second edition, Butterworth-Heinemann, Linacre house, Jordan Hill, Oxford Publisher, 1-314

Liu X. and Ban S., 2017, Effects of acclimatization on metabolic plasticity of Eodiaptomus japonicus (Copepoda: Calanoida) determined using an optical oxygen meter, Journal of PlanktonResearch, 39 (1): 111-121

https://doi.org/10.1093/plankt/fbw084

Matus D.Q., 2006, Broad taxon and gene sampling indicate that Chaetognaths are protostomes, Current Biology, 16(15): 575-576

https://doi.org/10.1016/j.cub.2006.07.017
PMid:16890509

Santhanam R., and Srinivasan A., 1994, A munual of marine zooplankton, Oxford and IBH publishing company. Pvt. LTD, 66 Janpath, New Delhi, India: 1-160

Sterner R.W., 2009, Role of zooplankton in aquatic ecosystems. In Likens, G.E. ed., Encyclopedia of inland waters, 1^st edition. Elsevier, Oxford, UK, pp.678-688

https://doi.org/10.1016/B978-012370626-3.00153-8

Stocker D.K., 1999, Mix trophy among Dinoflagellates, The Journal of Eukaryotic Microbiology, 46(4): 397-401

https://doi.org/10.1111/j.1550-7408.1999.tb04619.x