Off the Reef

Go off the beaten path with Umeed Mistry as he brings you on an eye-open­ing ex­plo­ration of all the quirky and in­ter­est­ing crea­tures that live on the sand flats, silt beds and sea­grass mead­ows of the In­dian Ocean

Asian Diver (English) - - Contents - By Umeed Mistry

A quick on­line search for scuba div­ing in In­dia brings up the An­daman and Lak­shad­weep Is­lands as the top scuba hol­i­day des­ti­na­tions in the coun­try, with Ne­trani, Goa and Pondicherry also at­tract­ing some of the div­ing fra­ter­nity to these less clear, but no less in­ter­est­ing wa­ters. And from these des­ti­na­tions, the top-rated dive sites tend to be co­ral reefs and a few ar­ti­fi­cial reefs (in­clud­ing ship­wrecks) that are teem­ing with a va­ri­ety of dif­fer­ent fish and crus­tacean species, and with vary­ing amounts of co­ral growth.

In my time spent pho­tograph­ing In­dia’s wa­ters, I have had the good for­tune of be­ing able to dive in some places where most recre­ational divers wouldn’t think to go. A cur­sory glance over these dive sites re­veals very lit­tle. And with a few ex­cep­tional in­di­vid­u­als whom I am grate­ful to, most dive op­er­a­tors aren’t in­ter­ested enough to visit these sites and aren’t knowl­edge­able enough to make these sites in­ter­est­ing for their div­ing guests.

But the truth is that there is al­ways some­thing to see – as many of the guides from the mec­cas of muck div­ing will tes­tify to. And if you’ve be­come fa­mil­iar with reef crea­tures from around the world, then you are likely to find some very alien and very sur­pris­ing life off the reef. Some of these habi­tats in­clude sea­grass beds, sand flats, silt beds ad­ja­cent to man­grove forests and a va­ri­ety of jet­ties that range from be­ing some­what clean to com­pletely over­run with trash.

Many crea­tures choose to live off the reef. One rea­son for this may be that there is less com­pe­ti­tion for ter­ri­tory and food in these other, seem­ingly des­o­late habi­tats. How­ever, the “de­ci­sion” to live off the reef comes with its own set of chal­lenges, for which many crea­tures have evolved cer­tain adap­ta­tions and have fos­tered cer­tain re­la­tion­ships that al­low them to thrive in what might oth­er­wise be con­sid­ered com­par­a­tively in­hos­pitable spa­ces.

For ex­am­ple, sand flats and silt beds pro­vide lit­tle or no solid sub­strate upon which to set­tle. On a reef, ses­sile crea­tures like many anemones, feather stars and sponges at­tach them­selves to rocks or co­ral with­out a prob­lem. This, how­ever, proves an al­most in­sur­mount­able ob­sta­cle on con­stantly shift­ing sand and silt beds. En­ter the her­mit crab. It is quite com­mon to find her­mit crabs with small anemones fixed to their shells. In this in­stance, the re­la­tion­ship is mu­tu­ally ben­e­fi­cial. The anemone finds a hard sur­face upon which to set­tle, while also get­ting car­ried about to dif­fer­ent places on the sandy ocean floor. The her­mit crab ben­e­fits from the sting­ing ten­ta­cles of the anemone, which help to ward off would-be preda­tors. A less com­mon sight is a feather star hitch­ing a ride on the back of a her­mit crab.

An­other crea­ture that in­vari­ably at­tracts other an­i­mals is the sea pen. These in­ver­te­brates live in ver­ti­cal bur­rows in the sand, with a feather-like part of their bod­ies stick­ing out into the

One rea­son for liv­ing off the reef may be that there is less com­pe­ti­tion for ter­ri­tory and food in these other,

seem­ingly des­o­late habi­tats

wa­ter. They re­sem­ble the feather quills of old. On an ocean bot­tom de­void of any fea­tures, sea pens form an­chors that many other crea­tures have come to rely on. Bar­na­cles cling to them while pick­ing plank­ton out of the wa­ter Some tiny crus­taceans hide within their feath­ery struc­tures, even lay­ing eggs on these an­i­mals.

An­other chal­lenge of liv­ing on flat, fea­ture­less muck bot­toms is the dif­fi­culty of re­main­ing un­seen – whether to hunt prey or elude preda­tors. Some pipefish have evolved to look like sticks, float­ing along on the cur­rent. Many fish have evolved colours and pat­terns that al­low them to blend per­fectly into the sand. Many crea­tures make bur­rows, and some of them emerge only un­der cover of dark­ness. And some have de­vel­oped the in­ge­nious use of tools, which al­lows them to tra­verse these un­der­wa­ter deserts with rel­a­tive im­punity.

One such re­mark­able an­i­mal is the oc­to­pus. In many parts of In­dia, I have ob­served oc­to­pus in­hab­it­ing sand flats and us­ing dis­carded shells for their pro­tec­tion. Some of them em­ploy the rel­a­tively straight­for­ward method of duck­ing into a larger, empty snail shell, which they some­times claim as their home. But there are oth­ers that need the free­dom to roam the sand flats and not be bound to one snail shell refuge. These in­trepid cephalopods drag clam shells, co­conut shells and even dis­carded food cans around with them. When a po­ten­tial threat ap­proaches, they stop their drag­ging shuf­fle, climb into their por­ta­ble refuges and use their many ten­ta­cles to close their shel­ters around them, of­ten with just an eye peep­ing out.

In sea­grass mead­ows, where there is lit­tle to hide be­neath, sponge crabs have taken to car­ry­ing large pieces of sponges above their bod­ies. They seem to up­turn the third leg on ei­ther side of their bod­ies, and use these legs to sup­port the sponge above them – not un­like the lug­gage porters at In­dian train sta­tions! The sponges them­selves are of­ten alive, and some­times large enough to have other smaller crus­taceans, brit­tle stars and a mini-ecosys­tem of in­ver­te­brates be­ing fer­ried here and there by the en­ter­pris­ing crab. A diver who has never en­coun­tered a sponge crab might, from a dis­tance, won­der at the piece of sponge skit­ter­ing about on the sea floor.

All these var­ied in­hab­i­tants on muck, sand, silt and sea­grass bot­toms in­vari­ably at­tract preda­tors. In these open habi­tats, cam­ou­flage be­comes cru­cial to suc­cess­ful hunt­ing. One of the ab­so­lute mas­ters of this game of sub­terfuge is the frog­fish. These fish come in all sorts of colours, sizes and tex­tures and many of them have a va­ri­ety of growths on their skin, thereby in­spir­ing names like hairy frog­fish, warty frog­fish, painted frog­fish and freck­led frog­fish. These fish, also known as an­gler­fish, shuf­fle im­per­cep­ti­bly to­wards other fish and then sit in wait. They some­times use a “lure” at the end of a fish­ing-rod like ap­pendage at the top of their heads to at­tract a fish’s at­ten­tion. When suit­able prey is within strik­ing dis­tance, the frog­fish lunges, open­ing its very dis­ten­si­ble mouth so quickly that the prey is swal­lowed in the suc­tion of wa­ter cre­ated by the move­ment.

An­other suc­cess­ful preda­tor but with a dif­fer­ent strat­egy for hunt­ing is the floun­der. These flat fish are of­ten ex­actly the colour of the sand. They have a pair of eyes lo­cated at the top of their heads that al­lows them to watch their sandy world while the rest of their bod­ies re­mains be­neath the sand. Swim­ming with a gen­tle un­du­lat­ing move­ment of their flat­tened bod­ies, these fish sneak up on shrimp, small crabs and other prey. When they fi­nally strike, all that’s left is a cloud of sand where their hap­less vic­tim stood.

In­dia’s wa­ters haven’t made it to muck div­ing head­lines in the in­ter­na­tional div­ing com­mu­nity.

The denizens of these types of habi­tats may not be as charis­matic as the brightly coloured fish, cu­ri­ous tur­tles or large sharks and rays that one may en­counter on the reef. But their lives are no less in­ter­est­ing. Many of these crea­tures have evolved ex­tra­or­di­nary adap­ta­tions and com­par­a­tively ec­cen­tric be­hav­iours to sur­vive in these spe­cial places.

So, the next time you get an op­por­tu­nity to dive off the reef in In­dia, take it! Chances are you’ll have some un­ex­pected en­coun­ters with some mem­o­rable crit­ters.


Many of these crea­tures have evolved ex­tra­or­di­nary adap­ta­tions and com­par­a­tively ec­cen­tric be­hav­iours to sur­vive in

these spe­cial places

TOP LEFT: Her­mit crab and feather starTOP RIGHT: Sea pen and brit­tle star MID­DLE: Trachyrham­phus pipefish,RIGHT: DragonetIM­AGES: Umeed Mistry

OP­PO­SITE PAGE TOP: Oc­to­puses OP­PO­SITE PAGE BOT­TOM: Sponge crab LEFT: A frog­fish at­tempts to at­tract a fish’s at­ten­tionBE­LOW: Painted frog­fishBOT­TOM: Floun­derIM­AGES: Umeed Mistry

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