Abstract: Bottom samples were collected monthly between September 2005 and November 2006 from 3 stations in order to determine Chironomidae larva and their seasonal distributions in TMI 12 Pond. During the study period 14 species belonging to 2 subfamily of Chironomidae were recorded. Chironomus plumosus was determined as the dominant species. Chironomus plumosus, Chironomus thummi, Chironomus anthracinus and Chironomus tentans were present in all stations. The most numbers of larvae were recorded in winter, the least were recorded in spring months. Also spring was recorded as the poorest season as to Shannon-Wiener species diversity index values. The other seasons index results were showed similarities with each other.

INTRODUCTION

Larval chironomidae species are important as food items for fish and other aquatic organisms. Since they contain important nutrient elements in high proportions especially proteins and are easily digestible, they are an indispensable source of food for fish. Further more, they prevent putrefaction on the floor for photosynthesis, thereby affecting the material cycle in a position way. They are also important as indicator organisms, i.e., the presence, absence or quantities of various species in a given body of water can indicate whether pollutants may be present.

Their fossils are also widely used by palaeolimnologists as indicators of past environmental changes including past climatic changes (Walker, 2001). Some of researches on Chironomid in Turkey were conducted by Sahin and Baysal (1972), Koirgiz (1988), Sahin (1980, 1987a, b), Gozler and Sen (1993), Ozkan (2006a, b, 2007), Ozkan and Kirgiz (1995), Ozdemir and Sen (1991), Ustaoglu et al. (2005). In this study, it has been aimed to contribute to Turkey’s Chironomidae fauna by the identification of the samples of TMI 12 Pond.

MATERIALS AND METHODS

TMI 12 pond is 22 km from faraway from Elazig and 100 km away from Diyarbakir city center and located between Elazig-Diyarbakir highway (22 km) Pond is connected with a small natural channel with right next to Hazar Lake that is located nearby the pond. The ground of pond is muddy and completely covered with water plants. Benthos specimens were collected monthly with Ekman Grab from three stations that thought to be characterized the features of pond between September 2005- November 2006 from TMI 12 Pond (Elazig). Samples could not be taken due to bad weather conditions in january. Samples of mud taken were cleaned in pans whose meshes are in different size and collected larvae were put into 250 mL plastic bottles containing 70% alcohol. Firstly temporary and then permanent preparations were done by Sahin and Ozkan methods. During this treatment firstly head capsules were boiled in 10% KOH for 5-15 min for removing waste tissues. Then they were taken to 80-90-100% alcohol series for 10 min each and were kept in xylene for 1-2 min and closed with entellan. Species determination was done under microscope marked Nikon (Cranston, 1982; Sahin, 1980; Epler, 1995). During all study periods, water temperature, disolved oxygen and pH were measured in situ by using digital Oxi 315i/SET Oxygen meter and Lamotte (pH 5-WC) pH meter.

To eludicate the Chironomidae fauna structure, dominance index, Shannon Weaver Diversity Index, Sorenson Similarity Index, Margalef Species Richness Index were used. Formulas were used to calculate the indexes:

Shannon weaver:

Sorenson similarity index:

Margalef species richness index:

RESULTS AND DISCUSSION

During the investigation period between September 2005 and November 2006 in TMI 12 Pond, 11 genus and 14 species belonging to 2 subfamilies Tanypodinae (25.58%) and Chironominae (71.42%) of Chironomideae family were identified. In all stations water temperature, dissolved oxygen and pH were measured in situ and values of all station were shown in Fig. 1.

Chironomid species of TMI 12 Pond identified from 3 stations (Table 1), their distributions with respect to time and stations were shown in (Table 2). Monthly individul number in m² of Chironomidae larva were calculated and shown in Fig. 2.

Totaly 8 species in station I, 13 species in station II and 4 species in station III were identifed (Table 1). The most larvae were determined in station I in October (1209 ind. m²), in station II in March (289 ind. m²), in station III in July (255 ind. m²). The least larvae were determined in station I in march (44 ind. m²), in station II in april, june and july (44 ind. m²), in station III in may. (44 ind. m²) (Fig. 2).

According to Sorenson similarity index results, a similarity as to species number between I-II and I-III stations with a value of 66.6% and a similarity between II-III stations 47.05% could be reported Shannon-Wiener index values were calculated as in station I in autumn (1.3807) (Table 3), in winter (1.0725) (Table 4) in spring (0) (Table 5) and in summer (0.9514) (Table 6), Spring has been recorded as the poorest season as to species diversity.

The other seasons index results were showed similarities. In station II, index values were calculated as in autumn (1.5118) (Table 3), in winter (1.4159) (Table 4), in spring (1.3906) (Table 5) and in summer (1.4891) (Table 6). No important difference as to species diversity was recorded in this season In station III, in index values were calculated as in spring (0) (Table 5), summer (0.9511) (Table 6).

No larva was recorded in other seasons. A little difference between station I and II could be observed when three stations were compared. Station III was the poorest area as to species diversity. In TMI 12 Pond 14 species belonging to Chironomidae were recorded. Among the species collected, C. plumosus, C. thummi, C. anthracinus, C. tentans were recorded in all stations (Table 1).

Fig. 1:	Water temperature, disolved oxygen and pH value in TMI 12 pond

Table 1:	Distrubution of chironomidae larvae according to stations in TMI 12 Pond

Table 2:	Monthly distrubution of chironomidae larvae in TMI 12 Pond

Fig. 2:	Monthly Individual numbers of Chironomidae larvae in TMI 12 Pond

The highest number of species was observed at station II with 13 species, followed by station I with 8 species D. tritomus, S. longipungionis, Z. sp., P. albimanus, P. varius and C. laccophila were observed only in one sampling period (Table 2).

Some of the identified species as Procladius sp., C. thummi, C. tettans were also recorded by Sen and Ozdemir in Haringet Stream, Akil, in Cip Dam lake, in Buyuk Stream. C. thummi and C. tentans which were found in high amounts in research area were mostly found in the low-stream and stagnant-water in muddy base among fallen leaves, water plants and algae (Sahin) TMI Pond also showed these qualities and these two species were recorded as dominant species.

Sahin and Baysal (1972) and Tellioglu observed C. thummi, C. tentans in high numbers in Hazar lake located nearby the study area. In both studies an increase in Chironomid larvae individual numbers were observed in spring as recorded in TMI 12 Pond.

Tasdemir et al. (2008) were recorded C. plumosus and C. anthracinus in high numbers during sampling periods in Gediz Delta and indicated that these species had got a wide tolerance and shows cosmopolite distribution. In Cip Dam lake (Elazig), Akil recorded 17 Chironomidea species. Among these species, Procladius (Holotanypus) sp., Chironomus thummi, Chironomus tentans, Chironomus anthracinus, Polypedilum nubeculosum and Stictochironomus longipugionionis were also determined in TMI 12 Pond.

Table 3:	Ecological indexes values in TMI 12 Pond in Autumn (N: Species numbers, S: Individual numbers, D: Margalef Index, Pi*Ln (Pi): Shannon-Weiner Index)

Table 4:	Ecological indexes values in TMI 12 Pond in winter (N: Species numbers, S: Individual numbers, D: Margalef Index, Pi*Ln (Pi): Shannon-Weiner Index)

Table 5:	Ecological indexes values in TMI 12 Pond in spring (N: Species numbers, S: Individual numbers, D: Margalef Index, Pi*Ln (Pi): Shannon-Weiner Index)

Table 6:	Ecological indexes values in TMI 12 Pond in summer (N: Species numbers, S: Individual numbers, D: Margalef Index, Pi*Ln (Pi): Shannon-Weiner Index)

Gozler and Sen (1993), reported C. thummi from Cip Fish Breeding Center as the most present species in all stations. This species was also present in all stations of TMI 12 Pond. Kara identified 19 Chironomidae species in Buyuk Stream (Pelte-Elazig). About 6 of them (Chironomus thummi, Chironomus anthracinus, Chironomus tentans, Paratendipes albimanus, Psectrotanypus varius and Procladius (Holotanypus) sp.) were also recorded in TMI 12 Pond. Tellioglu investigated Hazar Lake’s zoobenthos that is located nearby TMI 12 Pond. About 10 Chironomid larvae were recorded in the lake. Among the identified species Procladius sp., C. plumosus and C. thummi were also recorded inTMI 12 Pond.

In Hazar lake C. plumosus were recorded in all months. This species is one of the dominant larvae in TMI 12 Pond.

CONCLUSION

According to Sorenson similarity index results, similarities could be observed as to species number, between I-II and I-III stations with a value of 66.6% and between II-III stations with 47.05%. As there has been no research conducted at TMI 12 Chironomidae larvae before, all of the identified species are new records for TMI 12 Pond.

ACKNOWLEDGEMENTS

Researchers would like to thank to Asst. Prof. Dr. Ayda Tellioglu for helping us with the identifications and Firat University Scientific Research Project FUBAB for their financial support (Project No 1336).