Introduction

The Bay of Bengal is a Large Marine Ecosystem (LME) located in the tropics. Nearly 25% of the world's population resides in Bangladesh, India, Indonesia, Malaysia, Maldives, Myanmar, Sri Lanka and Thailand that border the Bay of Bengal. Alternating southwest and northeast monsoons, storm surges, cyclones and seasonal upwelling of bottom waters affect the hydrographical regimes in the Bay. The rivers discharge annually 1.6 x 1012 m3 fresh water and 1.35 x 109 tonnes of sediment into the bay (Subramanian, 1993) and change the hydrographical conditions from the oceanic to brackish water. The Bay is moderately productive, with 150-300 g C m2 y-1 (Aziz Ahmad, 1998).

The habitats in the Bay of Bengal include mudflats, rocky and sandy beaches, shoals, coral reefs, mangroves, marsh vegetation, lagoons, costal lakes, flood prone areas, coastal dunes, reclaimed areas, and salt pans. The Bay of Bengal has a rich diversity of species and ecosystems, which together make up the structure and functioning of the various marine habitats. Some coastal areas serve as nursery grounds for commercially important prawns. The Bay of Bengal has the northern most tuna fishing grounds. The Gulf of Mannar is one of the "biodiversity hotspots", with high numbers of species for many different types of marine organisms.

Increasing anthropogenic activities are damaging the natural ecosystems of the Bay. Plans are in progress for implementation of mega marine engineering projects such as the Sethu Samudram Canal Project (Subba Rao, 2008) in the Bay of Bengal, and others associated with construction of new ports. Agricultural activity is polluting the Bay with pesticides. Oil spills due to heavy oil tanker traffic threaten the diversity of biota, and affect the populations of species. Shipping activity has introduced exotic species into the Bay of Bengal (Subba Rao, 2005). Overfishing in the Bay is depleting species populations and poses a major threat to the livelihood of millions of fisherman in this region. An inventory of the species in all marine habitats is therefor essential for conservation, management and balanced and sustainable development of the ecosystem.

Defining Papers
The following papers describe seminal oceanographic research in the Bay of Bengal in the 1950's (E.C. La Fond), and later research and status of the Bay of Bengal in 2000 (D.V. Subba Rao).

by E.C. La Fond
Reprinted from the "Proceedings of the Indian Academy of Sciences," Vol. XLVI, 1957, with permission.

"The Indian Ocean remains one of the unexplored frontiers of our earth. It encompasses nearly 5,000 miles of coast-line and stretches hundreds of miles to the south, east, and west. It has an area 23 times as great as that of India itself and is the only major ocean named after a country. It is only fitting, therefore, that the study of this vast body of water has been taken up as a major subject here in India. The Andhra University, a pioneer in many fields, has introduced the scientific study of the north-eastern part of the Indian Ocean - the Bay of Bengal into its curriculum, and some of the progress in this field is here reported. ..."
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Photos from paper (PDF)

by D.V. Subba Rao
Reprinted from "Seas at the Millenium: An Environmental Evaluation," Edited by Charles R.C. Shepard, Pergamon, 2000, with permission.

"The Bay of Bengal has several remarkable features. It has a huge influx of fresh water from several major rivers, it is affected by intense northeast and southwest monsoon winds, of which the latter breed cyclones. In the bay there is a seasonal anticyclonic coastal current which is seasonally replaced by a cyclonic current, and unlike most coastal regions, there is a western boundary coastal upwelling.

The Bay supports various tropical biotopes such as brackish lakes, estuaries, mangroves, coral reefs, and offshore waters with a great diversity of marine fauna and flora. The steadily growing coastal population (~55 million) utilizes the coastal zone for several purposes. Increasing development pressure from urban settlements, industry, fishery, mariculture, ports and harbours has resulted in the alteration of coastline, loss of critical habitats, and pollution of the environment, giving rise to serious environmental and socio-economic problems. Massive education of the public about the environment, impending disasters, mitigation measures, and the need for conservation of resources and sustainable development are all crucial to our understanding or use of this unique sea. There is a need for the creation of a coastal zone management authority empowered to implement environmental regulations, and a need to establish regional scientific programmes. .."
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Earlier studies
1784
Sir William Jones
1839
Dr. Nathaniel Wallich
1841
John McClelland
1832-1862
Marine Survey of India (MSI)
1874-1881
J. Armstrong, first Surgeon Naturalist MSI
1888-1901
Lt. Col A.W. Alcock, Surgeon Naturalist MSI
1902
N. Annandale, Surgeon Naturalist MSI
1910-1926
Lt. Col. R.B.S. Sewell, Surgeon Naturalist MSI
1947- to date
Coastal Universities, Central Marine Fisheries Research Institute, National Institute of Oceanography, Zoological Survey of India
Fig. 2. NIO Zoological Survey of India Cruise Tracks in Bay of Bengal
1952-1955
Andhra University conducted 52 Oceanographic research cruises under the leadership of Professor E.C. La Fond
Fig. 1. Andhra Univ. Cruise Tracks in Bay of Bengal

Expeditions
1872-1876
The British Challenger
1896-1899
The German Valdivia
1899-1900
The Dutch Siboga
1930-1934
The British H.M.S. Investigator, John Murray
1928-1930
The Danish Dana
1950-1952
The Danish Galathea
1950-1952
The Swedish Albatross
1959-1965
The multinational International Indian Ocean Expedition, IIOE
Fig. 1. IIOE Cruise Tracks in Bay of Bengal

Indian Marine Institutions
Institutes on the East Coast of India that carry marine biological studies:
  • University of Calcutta (West Bengal)
  • Andhra University (Andhra Pradesh)
  • Berhampur University (Orissa)
  • Anna University (Tamil Nadu)
  • Annamalai University (Tamil Nadu)
  • Central Marine Fisheries Research Institute, Mandapam
  • National Institute of Oceanography, Goa, India, and its branch at Visakhapatnam
The Bay of Bengal
  • Location: South Asia between latitudes 50 and 220 deg N and longitudes 80 and 900 deg E.
  • Primary sources: Indian Ocean
  • Basin countries: India, Bangladesh, Myanmar (Burma), Thailand, Indonesia, Sri Lanka
  • Rivers: Padma (a distributary of the Ganges), Meghna (a distributary of the Brahmaputra), Jamuna (a branch of the Brahmaputra), Ayeyarwady (Irrawady) , Mahanadi, Godavari, Krishna, Kaveri, Cooum, Pennar.
  • Islands: 572
  • Ports: Cuddalore, Ennore, Chennai, Karaikal, Pondicherry, Tuticorin, Kakinada, Machilipatnam, Vishakhapatnam, Paradip, Kolkata, Mongla, Chittagong and Yangon
  • Coastal brackish water lakes: Chilka, Pulicat
  • Max length: 2,090 km
  • Max width 1,610 km
  • Surface area: 2,172,000 kmĀ²
  • Average depth: 2,600 m
  • Max depth: 4,694 m
Bay of Bengal Region Wetlands
Region
Area of wetlands, km2
Indian coast
40,230
Bay of Bengal
12,354
West Bengal contributes
3,604
Orissa
1,854
Andhra Pradesh
1,855
Tamil Nadu
3,987
Andaman and Nicobars
1,078

Diversity of Marine Habitats and Marine Sciences

The Bay of Bengal region has 31 Marine Protected Areas (MPAs) with an area of 6271 km2; (Singh 2003). Of these, 13 MPAs are from the Bay of Bengal along the east coast of India and 15 are from the Andaman and Nicobar area.

The variety of habitats in the Bay of Bengal include mangroves, coral reefs, estuaries, lagoons, rocky shores, sandy beaches and brackish waters. Besides the biota in these habitats, foulers that settle on substrata, borers that destroy wood, corals and rocks, and commensals and parasites contribute to the diversity of the biota.

Localities and Occurrences
This compendium is not a review of all published reports from the Bay of Bengal. Entries are taken from the original publications and no attempts have been made regarding the spelling, authority, year and distribution. For example Skeletonema costatum was spelled also as Sceletonema costatum.

Periodically, in India the same place is indicated by more than one name; for example Waltair, Vizag and Visakhapatnam. Similarly Chennai and Madras; Odisha and Orissa are the same.