• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11
  12. 12
  13. 13
  14. 14
  15. 15
  16. 16
  17. 17

Abundance, Distribution and Species Diversity of Invertebrates Collected By Commercial Trawler From Near Shore Coastal Areas of Karachi, Pakistan (Northern Arabian Sea).

Extracts from this document...


ABUNDANCE, DISTRIBUTION AND SPECIES DIVERSITY OF INVERTEBRATES COLLECTED BY COMMERCIAL TRAWLER FROM NEAR SHORE COASTAL AREAS OF KARACHI, PAKISTAN (NORTHERN ARABIAN SEA). RAOOF MUHAMMAD NIAZI* NAUREEN AZIZ QURESHI **AND MUZAMMIL AHMED** *GOVERNMENT CITY COLLEGE, F. B. AREA, KARACHI. raoofmniazi@hotmail.com **CENTRE OF EXCELLENCE IN MARINE BIOLOGY, UNIVERSITY OF KARACHI, KARACHI. Total number of figures included: 5 Running Title: DIVERSITY OF INVERTEBRATES COLLECTED BY COMMERCIAL TRAWLER ABSTRACT The distribution and abundance of benthic macro fauna in near shore waters off Karachi is studied for over a period of one year. For this purpose the marine benthic fauna was collected every month from otter trawl catches of "Hella" fishing trips undertaken by Karachi based commercial shrimp trawlers fishing in depths of about 12 meters. A total of 76 species of invertebrates belonging to 38 families were studied. The distribution and abundance varied with seasons and maximum number of invertebrate species was found during the monsoon season when salinity was low and temperature was high. With increasing salinity and falling temperature the number of invertebrate species in the study area, seemed to decrease. The diversity of invertebrate species collected was studied using the diversity indices and the seasonal variation in the diversity indices was also discussed. ...read more.


The trawling operations were generally a daylong and are locally known by the name of "Hella" fishery. Random sample from the total catch of the trawl was separated on every trip for subsequent study in laboratory. Identifications of invertebrates were made to species or generic level with the help of available literature. During the monthly observations temperature was measured by the thermometer and salinity by refractometer in the laboratory. RESULT AND DISCUSSION On the fishing grounds off Karachi invertebrate fauna was found abundant. A total of 76 species of invertebrates belonging to 38 families were collected. In (Table 1) the month-wise occurrence of three most abundant invertebrate species in the study area were shown among these Oratosquilla nepa, Charybdis callianassaand and Bulla ampulla were found to be more numerous then other species in the area, while (Table 2) Shows the dominant number of individuals of invertebrate species in near shore waters off Karachi. Monthly distribution of invertebrate species shown in (Fig.1) The Shannon and Wiener diversity index was use for the evaluation of species diversity in each collection of the months (Table 3). Diversity index is a mathematical measure of species diversity in a community. ...read more.


2 Dominant invertebrate species in near shore waters off Karachi from December, 1992 to November, 1993. N= Total number of individuals. S. NO. SPECIES N RANK 1. Oratosquilla nepa 188 I 2. Charybdis callianassa 184 II 3. Bulla ampulla 71 III 4. Thenus orientalis 51 IV 5. Portunus sanguinolentus 49 V 6. Portunus hastatoides 43 VI 7. Loligo duvauceli 41 VII 8. Sepiella inermis 40 VIII 9. Oratosquilla interrupta 35 IX 10. Calappa lophos 30 X 11. Charybdis cruciata 22 XI 12. Astropecten indicus 22 XI Figure 1. Monthly distributions of invertebrate species in near shore waters of Arabian Sea off Karachi. Table 3. Diversity and equitability of invertebrate species from near shore waters of Karachi. MONTHS DIVERSITY ( H? ) EQUITABILITY ( J ) December 1.20826 1.11961 January 0.9397 0.81989 February 0.72141 0.30903 March 0.79176 0.36946 April 1.0374 0.55326 May 1.21162 0.62965 June 1.27644 0.75130 July 1.25962 0.68288 August 1.00853 0.64803 September 1.18482 0.74467 October 1.06643 0.65697 November 0.82452 0.34095 Figure 2. Monthly Diversity index (H) of Invertebrates from near shore waters of Karachi, (Northern Arabian Sea) Figure 4. Mean Seasonal Diversity index (H') of invertebrates from near shore Karachi,(Northern Arabian Sea) Figure 3. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our University Degree Marine & Freshwater Biology section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related University Degree Marine & Freshwater Biology essays

  1. Marked by a teacher

    Plankton - Marine Biology,Scientific Paper

    3 star(s)

    the ingestion of whole cells, 2. use of a feeding tube called a peduncle and 3. use of a cytoplasmic veil e.g. pallium. Many Hertotrophic nanoflagellates compete with copeopods for ciliates and other microorganisms. Photosynthetic nanoflagellates only use light from the sun to produce energy.

  2. Photo Identification methods

    on humpback whale and fin whale; body on doplhins and killer whale. We make photographie head also. In the resulting photographs are follow in dorsal fin nicks, notches, shape, scars and scratches; in fluke color papetters, scars;in body color patterns, scars and scratches; in head callosities.

  1. An investigation into the abundance of freshwater invertebrates in pools and riffles at six ...

    5 6 9 10 11 12 ?R1 = 25 ?R2 = 53 U1 = (n � n) + (0.5 � n) (n + 1) - ?R2 = (6 � 6) + (0.5 � 6) (6 + 1) - 53 = 4 U2 = (n � n) + (0.5 � n)

  2. A comparison of marine organisms on shale & limestone coasts. Doolin, Ireland.

    Two transects were set out in both sites, each transect going from the shoreline inland until the rockpools stop. All of the rock pools were selected within one metre of transect line for further observation. Each pool was then studied to identify and list marine pool flora and fauna, this

  1. Do patients with chronic low back pain have proprioceptive deficits in their lumbar spine?

    Research for low back pain and visual feedback training is limited and therefore this study will also help to show how much of an influence sight has over proprioception. A number of methods have been employed to measure proprioception, including the 3-space Fastrak device (Newcomer, 2000, O'Sullivan, 2003), force plates (Nies 1991, 1998, Mientjes 1999, Wolff 1998)

  2. Moreton Bay Marine Ecology

    Biodiversity remains difficult to quantify accurately, but accuracy is not needed to develop an understanding of how biodiversity has changed over time, the responsibility for change and the consequences of such change to the ecosystem and human wellbeing at both Green Island and Saint Helena Island (Green Facts).

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work