RUCHA KARKAREY AND VARDHAN PATANKAR
Edited version published in The Hindu School
Can you imagine seeing a thousand leopards in a forest patch, the size of a football field? As you make your way through the forest thicket, you are elated when you see your first leopard, peering down at you from the branches. You consider yourself very lucky if you see two more, but a thousand leopards at one time? This idea seems a little impossible, doesn’t it? Not to us, because we have seen them with our own eyes; hundreds of them, all around us!!
Sometimes even the impossible seems possible. They do not call it ‘the sea of possibility’ for nothing! If you want to know what we are talking about, then just take a dive into the sea and with a ‘bit’ of luck you might just witness for yourself what we experienced during our recent trip.
The forest we speak of is a coral reef from a remote atoll in the Lakshadweep archipelago and the ‘leopard’, a species of reef fish known as the squaretail grouper (Plectropomus areolatus). A top carnivorous fish, with black spots on its body, which likes to hunt by ambushing its prey, which prefers to remain solitary, making it a formidable reef predator, just like our large cats in the forests. This grouper shows a unique mating behaviour, where several individuals aggregate at certain areas at certain times of the year, to reproduce. These aggregations are known as ‘spawning aggregations’ and the main focus of our story.
The squaretail grouper is a common fish on coral reefs in the Lakshadweep. During our island-wide monitoring study in 2011, we spotted one or two individuals on most reefs. At one particular site, however, wesaw them in unbelievable numbers of over fifty! They were perched everywhere upon the reef, displaying flashy colour patterns and circling each other.While watching them, a common thought transcended us, could it be that we were amidst a grouper spawning aggregation? Though the possibility of this being a spawning aggregation was high, the island was so remote, that we had to curtail our investigation due to logistical constraints.
Once back on the mainland we read up on research and spoke to experts who had studied these aggregations before. They pointed us to an interesting fact that many grouper spawning aggregations take place yearly at the same locations. There was a big chance of seeing the aggregation once again, if we were to head back to our site at the same time as last year!! We chalked out a plan and in 2012 set out to the islands on a purposeful expedition—this time not to merely experience the aggregation but to try and study it further.
With Rohan leading the team, we left Kadmat island at mid-night in a tiny tuna boat kundalum; an army of 7 with supplies for 6 days. Just the prospect of witnessing this event again, was exciting but we had to brace ourselves for the uncertainly—the timing, the location, weather— hoping that everything would work out in our favour.
The first three days were not as we imagined. On a few reef sites we did not spot even a single grouper, whereas on the others we spotted only one or two. We dived at several sites around the atoll to look for clues of spawning behaviours—their gathering in huge numbers, the mate display, males guarding a site—but saw nothing as the research described. We intensified our searches, dived longer, and looked more carefully at a few individuals, but to no avail.
Just as we were about to give up, a day before the new moon, the tide turned, so to speak. We returned to a site where we had reported the highest grouper numbers from the day before and we were stunned! The reef was swarming with squaretail groupers. From a ‘bird-eye view’, we saw the site was packed by this species with individuals as big as 75-80 cm and little elbowroom to spare between them! We saw them fighting aggressively with each other in order to establish small territories—could these be males? We saw shoals of 200 individuals of squaretail grouper entering the aggregation site at high tide, and interacting with the territorial ‘males’- could these be females? The entire incident unfurled in front of us like a 50-minute play and we struggled to collect our data.
That night we retired to our field station, each finding a way to identify with the days proceedings. More than any other feeling in the world, we were silenced, overwhelmed. Our colleague Ommni, a local from Lakshadweep, who has dived these waters for the past 15 years, but has never witnessed such an event, aptly described it as ‘Seeing a thousand leopards in the sea’.
Our preliminary work on the aggregation estimated over two thousands individuals in the aggregation. By the third day all signs of the aggregation had completely vanished from the site. It was sheer luck and a little bit of instinct that got us to the right place at the right time. For a while, we revelled in the fact that we witnessed such a rare occurrence.
It is needless to say that such large, periodic aggregations of fish do not go unnoticed by local fisherfolk. Spawning aggregations of fishes provide a lucrative opportunity for fishermen to obtain large catches of fish, with minimum effort and for commercially important fishes like groupers, such activities can decimate entire local populations in a matter of a few days. In this respect, these observations go beyond a sense of wonder and have serious implications for conservation in the Lakshadweep.