Karwar-based marine biologist Dr Prakash Mesta agrees that extreme and untimely heat is not good for marine life.
When dead fish with swollen bellies wash up on beaches in the thousands, when the coastline recedes alarmingly and when fishing boats venture deep into the deep blue sea and yet return with empty nets, it is obvious that our coastal eco-system is facing a serious threat.
Experts put the blame on climate change, unprecedented rise in temperature and the changing behaviour of the sea which, if left unchecked, could play havoc with our hauntingly beautiful beaches and marine life. Vinay Madhav and Gururaj A. Paniyadi find out the reasons why Karnataka’s coast is fast becoming an ecologist’s nightmare and why it is essential to act before it is too late.
It was virtually a blast of hot air in coastal Karnataka and Mangaluru in particular this January with the mercury hovering around 39 degrees Celsius — the day even went into the record books. But not everyone is amused with the record as temperatures in the coast have breached the levels the region usually witnesses in peak summer. And most worried is the community of marine biologists across coastal districts like Mangaluru, Udupi and Uttara Kannada. All they can do now is stare at the placid waters of the Arabian Sea and say, “This is not good. A lot have changed in sea behavior in the last one decade.”And maybe blame global warming for drastic changes in the climate.
Karwar-based marine biologist Dr Prakash Mesta agrees that extreme and untimely heat is not good for marine life. “Coastal behaviour changes with the tides, which are triggered by air. When it is extremely hot, the air heats up and starts moving towards cooler regions which alters the direction of the tide. Consequently, the sea becomes much calmer at the beaches,” he said. But what is of concern is that the beaches are changing shape with the one in Karwar town getting extended while the summer sand beach in Mangaluru is receding too fast for anyone’s comfort. Consequently, sand deposits are springing up on the beaches of Karwar and declining in Mangaluru-two towns over 271 km apart.
“This is happening because of climate change as sea behaviour is related to the topography. Karwar is a shelter harbour, which has a lot of islands. During the monsoon months, fishing boats, even from Kochi in Kerala take shelter in this place as they consider it safe. Now with the beach getting extended and sea behaviour changing, we are really worried,” Dr Mesta says.
Normally, during the monsoon, the sea brings sand to the shore and takes it back later. However, since the tides are losing force, the equilibrium is fast getting lost with a lot of sand deposits remaining on the beaches. This could have an adverse effect on the entire natural ecosystem, say experts.
Ten years ago, during the high tide, waves used to hit the place where the present Mini-Vidhana Soudha in Karwar stands. Now, the sea has receded by at least half a km. The situation is totally different on Mangaluru beach where some places are fast losing the beach stretch while in others, the sea is receding too fast for anyone’s comfort.
Former chief of Mogaveera Vyavasthapaka Mandali and Panambur Beach Tourism Development Project CEO Yathish Baikampady says that in recent years, the sea is getting closer to the coast, a phenomenon which continues even after the monsoon.
“During the rainy season, the sea comes near the shore and after the monsoon — between August and May, it moves back. At that time the seashore and the beach get wider. But in recent years, the sea has not moved back much. The shore and the beach are decreasing at many places in the region,” he says.
Prof. K.S. Jayappa of the Marine geology department at Mangaluru University, who specialises in estuarine and coastal processes agrees with this view. “The sea is experiencing a progredation and recession phenomenon. While the beach usually gets bigger after the monsoon, it has been receding in recent years with the sea eating into the coast. The sand which goes offshore during and after the monsoon usually comes back to the beaches once the rains are over but as the input of sand has decreased, the beach is declining in its reach,” Prof. Jayappa explains.
He feels vented dams and sand mining in estuaries too are to blame for the fall in the amount of sand getting washed onto the shore. The construction of sea walls has led to a loss in the beach stretch, he says and cites the example of the Summer Sands beach resort at Ullal where the sea was about 1 km away from the beach resort in the 1980s. “Now the sea has not only covered this 1 km, it is virtually knocking at the doors of the resort,” he notes.
Human intervention and the construction of a sea wall have also led to the beach at Bengre in north Mangaluru increasing in its reach while there is erosion and an advancing sea to the south.
Increasing or receding beaches are just part of the problem. What is of more concern are the changes in marine life migration and fishing patterns.
For instance, Mr Vasudeva, who owns fishing trawlers, is a worried man this year. Usually, during December and January, fishing boats would return filled with fish every time they ventured into the sea. But this year, there is hardly any catch worth talking about with the boats returning almost empty.
Like Vasudeva, most fishermen were happy that the repeated toofans or cyclones in the Arabian Sea during the monsoon and in subsequent months would inevitably result in a good fish harvest. With the phase after the monsoon last year witnessing several weather depressions in the sea, fishermen were naturally hoping to reap the bounty but surprisingly, there is hardly a big catch.
Experts agree saying that weather patterns have led to a drastic change in fish behaviour. There is a fall in the usual fish like Sardine, Silver Fish and Mackerel coming into the nets but surprisingly, new fish varieties are being netted now.
“For the last two years, we have been catching the Odonus species of fish a lot,” says Dr Sujatha Thomas, Principal Scientist, CMFRI- Mangaluru.
“This variety was considered a menace when it initially started entering the nets but now we realise it has economic value too. We cannot pinpoint one single reason for the change in fish variety as the ocean is a dynamic system and there are many changes happening in fishing patterns and sea temperature,” she says and recollects that a few years ago, it was the same case with the puffer fish suddenly dominating the catch.
Dr Mesta says the changing patterns in the fish harvest are due to the migration of marine life. “Like us, they also look for ideal places to survive. For example, Karwar was famous for sardine and mackerel and their traditional habitat used to be between Kochi and the Ratnagiri region in Maharashtra. They were never found in the Bay of Bengal but now, fishermen in Chennai and even in Gujarat are getting huge amounts of these fish in their nets. It is just that they have migrated to those regions,” he explains. “There are several changes happening in marine diversity with many micro organisms and small marine life vanishing. We need a thorough study of the marine life we are losing. For example, bivalves, a class of marine and fresh water mussel has dwindled by over 75 per cent during the last 15 years. There may be multiple reasons behind the dwindling of these species. However, they play an important role in the marine ecosystem which is why a study is of utmost importance,” Dr Mesta stresses. It’s not onl
y marine life which is at risk, in Karwar, nearly half of the mangroves have been destroyed, which is something unheard of.
“During the last rain-induced floods, there was an enormous flow of fresh water into these mangroves. These are mangroves which thrive in saline water though it is common during the monsoon for fresh water from Kali river to accumulate in them. However, after the monsoon, we need high tides and the waves to come back and ensure the fresh water is salinated. In the absence of such tides, half of the mangroves have been destroyed. Mangroves play an important role in holding the soil together during cyclones and tsunamis and minimise the damage to the coast line which is why this is a huge problem,” Prof. Mesta says.