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International Journal of Marine Science 2013, Vol.3, No.12, 98-104
http://ijms.sophiapublisher.com
102
West coast of India reporting that the mudskipper
feeds on algae, diatoms, polychaetes, nematodes,
crustaceans and teleost eggs. No crustaceans were
recorded in the gut contents of the mudskipper,
B.
boddarti
. The dietary preference is probably of great
importance from one species to another and also the
geographical variations play a significant factor for
the food availability. In general, diatoms of the benthic
region are important contributors to primary
production in estuarine and marine coastal ecosystems
(Matheke and Horner, 1974). In which, pennate
diatoms are the dominant group in marine epipelic
communities (Underwood and Paterson, 1993; Aktan
and Aykulu, 2005) and are the main food source for
bottom fauna (Mazzella and Spinoccia, 1992;
Scipione and Mazzella, 1992). Sarkar et al (1980)
studied the food habits of the mudskipper
Pseudopocryptes dentatus
from the mudflats of the
Shatt Al-Arab estuary as well as along the coastal
regions of the Arab Gulf, and reported that the
Pennales diatoms constituted the maximum with 81%
and Centrales with 19% in the gut contents of the
mudskipper. True to this fact, in the present study also
the Pennales were also found to be dominant diatoms
than Centrale diatoms. Krishnamurthy (1971)
observed the primary peaks of diatoms and thus the
ingestion of large amounts of diatoms during March to
June and October to January is in good agreement
with the seasonal distribution pattern of phytoplankton
in Parangipettai waters (Krishnamurthy, 1971).
Seasonal changes in food availability may be caused
by changes in the habits available for foraging,
changes due to the life-history patterns of food
organisms and changes caused by the feeding
activities of the fish themselves (Wootton, 1990).
Similar observation was made in
B. pectinirostris
from Korea coast (Ryu et al., 1995). According to
them the fish fed principally on diatoms followed by
crusctaceans, mysids and delphasids. Nematodes were
found in the stomachs of the mudskipper,
B. boddarti
during the study period. Similarly Krishnamurthy et al
(1984) and Colombini et al (1996) reported that the
mudskippers feed on nematodes. Polychaetes were
found in moderate percentage (12%) in the stomach of
the mudskipper. Stebbins and Kalk (1961) and Macnae
and Kalk (1962) reported that the
Periophthalmus
sobrinus
preys on polychaetes and crustaceans.
Colombini et al (1996) while studying the foraging
strategy of mudskipper,
P. sobrinus
from Kenyan
mangroves reported that nearly 39% polychaetes in
their diet. In the stomach of the mudskippers, fish
eggs were present in good percentage during post
monsoon season and it may due to the fact that the
majority of estuarine teleosts spawn during this season
in Pichavaram mangroves. Algae were common
during post monsoon and summer seasons. While
skimming off the food from the mudflats, these
particles may also enter into their gut and the
heterotrophic bacteria present in that soil (Federle et
al., 1983) may indirectly be helpful in the digestion. In
the present study, there was a slight variation in the
percentages of the food items found in males and
females but Colombini et al (1996) observed that the
males had more varied diet than the females.
3 Material and Methods
3.1 Study area
Pichavaram mangrove (Lat. 1
1
°2
7
′N; Long. 79°47′E)
(Figure 4) is situated in the southeast coast of India,
amidst the Vellar estuary in the north and the Coleroon
estuary in the south. It is a repository of rare, endemic
and endangered species of mangroves. Those mangrove
genera include:
Avicennia, Rhizophora, Excoecaria,
Bruguiera,
Sonneratia,
Xylocarpus,
Ceriops,
Lumnitzera, Aegiceras, Suaeda, Acanthus
and
Sesuvium
. Mudflats selected for the present study lie
at Muzhukkuthurai (11°27′20N; 79°47′00E). The
exposure of mudflats occur during every low tides
where the numerous mudskippers and their burrows,
crabs, certain gastropod (
Telescopum telescopim
) can
be seen.
3.2 Gut content analysis
To assess the food and feeding habits, a total of 156 fishes
(juveniles, males and females: 32 to 182 mm TL)
specimens of
B. boddarti
were caught randomly from
the mudflats of Pichavaram mangroves during July
2011 to June 2012, with the help of cast nets and
nylon hand nets. Fishes were immediately preserved
in 5% formalin. For each specimen, its total length
(TL) in mm and weight in g, sex and maturity stages
were noted in fresh condition. During the present
study, the gut contents were estimated based on the
frequency of occurrence of different food materials