A week ago, locals of Sao Jacinto had raised concern over a large crowd of unskilled people gathering at the bay for collection of clams. Cyril Fernandes, Chicalim Biodiversity Chairman, had urged the Goa State Biodiversity Board (GSBB) to frame new guidelines and issue cards for identification of correct size of bivalves which can be collected.
Last year, GSBB had assured to take up a major project at Chicalim, Sao Jacinto and Sancoale bay to preserve this fragile ecosystem along the entire length of the river. The assurance was given during the installation of awareness hoarding which was organised to declare the Chicalim bay area an ecological fragile zone for windowpane oyster (Placuna placenta Linnaeus), said Nutella Cardoso, fisherwoman of Chicalim.
“Instead of giving mere assurances, government should act more seriously and critically to preserve and protect Goa’s delicacy”, added Cardoso.
Factors such as water pollution due to oil-spillage, dumping of garbage, discharge of sewage in river body, climate change, sand mining, pollution and monsoon behaviour has largely affected the aquatic species. With Goa largely taking up the projects of construction of bridges, the falling of debris in watercourse also disturbs the aquatic culture, said Dr Joe D'souza, a retired faculty member of Department of Microbiology department and Environmental Science of Goa University.
Dr Joe further said that the over-exploitation, human-turbulence and pollution have disrupted the food chain. He suggested that the roper monitoring of food-chain is mandatory and the factor has to be considered more seriously for maintaining the quality lifestyle.
“What human beings eat these days is fish contaminated with formalin, rice contaminated with arsenic and vegetables and fruits contaminated with organic fertilizers. Irony is that we are trying to earn more and enjoy the quality life. But in the haste of earning more we tend to lose quality health”, Dr Joe lamented.
“Increasing human intervention has not just led to the decline in the population of shellfish but also the marine fishes”, he added.
He further held casinos floating in river Mandovi to be responsible for the decline in aquatic species. Dr. Joe said, “Government in power has jeopardised the life of a common man in greed of earning quick money. Politicians are earning at a cost of the health of the Goan society”.
Asserting his point Dr. Joe said, “Captain of Ports has given free hand to concretise the Panjim-Betim jetty point for the benefit of casino lobby. Crores of rupees have been spent on concretion without taking scientists and researchers into consideration”.
“They don't mind spending money on ventilators and machines but do mind spending it arranging the quality food by proper monitoring for giving quality and healthy lifestyle to the people of Goa”, said Dr. Joe.
He claimed that the adulteration of fruits, pulses, vegetables, groceries, meat, cereals etc. in Goa has shown a quantum jump. “To save few bucks, food industry prefers to use inorganic food preservatives, food colours, growth hormones and steroids which in-turn is affecting the health of a common man”, he claimed.
Research suspects food adulteration to be a key reason behind rise in Cancer cases. "What we are consuming is not food but a slow poison", he claimed. Dr. Joe further asserted that as per research, the concretisation of bank of rivers, water bodies, creeks and bunds affects marine life and shellfishes.
A case study conducted at National Institute of Oceanography (NIO)-Goa has revealed the presence of cadmium (carcinogenic substance) in oysters above the safety level. which was harvested from Chicalim village situated at the mouth of river Zuari.
Chandan Shirodkar, assistant superintendent of aquaculture section, Department of Fisheries lamented about the unavailability of independent Research and Development unit in the Department of Fisheries.
“Department of Fisheries is lacking an independent research and development unit. We have to rely on National Institute of Oceanography (NIO) Dona Paula, Indian Agricultural Research Institute (ICAR) and other research laboratories to carry out the research”, added Shirodkar.
Stating reasons with an example for decline of marine species in river Mandovi, Dr. Joe said, “There was a time when we used to find Reef cod (Gobryo), Mangrove red snapper (Tamshyo), clams, Green Mussels (shinanyo) in Mandovi and now we are yearning even for their sight”.
The fact behind extinction of marine species is the incapable government which is unable to keep a track, said Dr. Joe
“Captain of ports is passing the ball in the court of department of fisheries which in turn will be blaming some other department for decline in marine species. Passing the buck to others court has now-a-days become modus operandi of every government official”, Dr. Joe stated in anguish.
Dr Chandrashekher Rivonkar, Senior Professor and Dean of School of Earth, Ocean and Atmospheric Sciences of Goa University, spoke about the consequences of human intervention on the life of shellfish.
Briefing about the method of mussel farming, Rivonkar said, “The green mussels can survive only at the specific location. They are usually found clumping together on wave-washed rocks, each attached to the rock by its byssus (sticky threads/silky fibres that glue mussels to slippery, wave-pounded rocks. Mussels make these threads by squeezing quick-setting liquid protein into a groove in their muscly foot, which form weak bonds with the rock).
Mussels require to be submerged at a particular depth into the sea in order so that they do not suffer from dehydration. Submergence into saline water at high tide and exposure to light at low tide is essential for their growth. They loosely attach to the surface and absorb nutrients in the water for their growth”.
Adding he said, “Mussels requires around a year to reach to their marketable size. Now-a-days, due to its higher market demand, the locals are getting engaged in un-cultured extraction (over-exploitation) which has resulted in drastic reduction in its population”.
Speaking exclusively about the decline in population of mussels, Rivonkar said, “They can dis-lodge from substrate due to thread failure, substrate failure, or both. Continues submergence into deeper layers create threat to their life from potential predators such as sea urchins. Yet another potential problem is spat availability”.
Rivonkar said that the survival of these shellfish depends upon environmental factors and the food availability. Destruction of habitat and that of seed are major reason behind the decline in their population.
Rivonkar said about the considerable research that is being done across the country to protect these species from going extinct. “Technique termed as 'the raft culture method' (commercial method of intensive aquaculture) is adopted by the researchers/fisherman community wherein the seeds are tied to the rope and are suspended to the rafts made up of bamboo poles such that the ropes doesn't touch the bottom of the sea. This protects the seeds from predators”, he added.
A joint case study conducted recently by the scientists and researchers of NIO-Goa, Academy of scientific and innovative research (Goa) along with Vellore Institute of Technology (VIT) at Sal river of South Goa had revealed the presence of micro plastic in aquatic species above the permissible level.
Sumit Biswas, Professor of Department of Biological Sciences, BITS Pilani, K K Birla said, “Chicalim/Sancoale bay was once a breeding ground of bivalve mollusks, the endangered windowpane oyster (mendis). This bivalve had lost its mark due to poor conservation status, which forced us to take up the project for its revival.
He said that the self-sustained incubator was fabricated and set up in the laboratory wherein the seeds of windowpane oysters were planted and made to reproduce in the incubator, as a conservation strategy. “We had started working on a project with the local community to revive and rejuvenate the windowpan oysters at Chicalim site.
“We formed groups of villagers and made them aware about the critical state of windowpane oysters in their village. We made them realise to how the sites of Chicalim bay which was once bountiful of windowpane oysters is showing a steep decline in its population”.
Professor Biswas said that the major project needs to be taken up to replicate the process of conservation along the entire length of the river and that the improvement at one site keeping the other patch un-improved doesn't help.
Commenting on decline in shellfish, Prof Biswas said, “The natural behaviour of aquatic species is such that they displace to some other location if the current condition is unfavourable for mating/ survival”.
Number of windowpane oysters found in the Chicalim bay is comparatively better than that of previous years; the number was zero in 2018, informed Prof Biswas. The same project has been now expanded for crabs, mussels continuing the conservation of previously taken up species.
“Another problem is over-exploitation. Harvesting immediately after the monsoon, the time when most of the shellfish breed, leads to destruction of their spats. Harvesting of shellfishes at such times not only leads to picking up of under-developed bivalves but also destroys the seeds”, added Prof Biswas.
According to Biswas, anthropogenic activities are main cause as far as the decline in marine life is concerned. He added saying, “Most of the shellfishes take the shelter of rocks and their life cycle is correlated. Disturbing the bed at the time of growth may lead to detachment of life from spats causing threat to their life”.
Nutella Cardoso, of Chicalim raised concern about the bewildered harvesting of clams (tisreo). She said, clams had re-emerged after almost six long years. “Unaware about the scientific approach of harvesting, people gather at the bay harvesting the clams beyond the sustainable level. The over-exploitation of clams had not only resulted in depletion of clam seeds but once it has even gone extinct”, she lamented.
Hand digging or scratching the sand using coconut shell to search for clams was the traditional method followed for harvesting the clams. Now-a-days the fishermen use modern method of scratching the sand with the help of metal teether tool for fish extraction.
Blaming the village panchayat for losing its control on local business, Cardoso said that the Panchayat is allowing everyone to pluck clams and windowpane oysters. Unaware about which ones to be plucked and which ones not to be, people exploit everything that they see leading to.
According to Naty Colaco, another fisherwoman from Chicalim, the fisherman's should stick to using the traditional tools like coconut shells and not iron tools. “Unaware about the scientific techniques of harvesting, people gather at the bay in large number and start harvesting the clams beyond the sustainable level. The over-exploitation of clams had not only resulted in depletion of clam seeds but once it has even gone extinct”, she added.
Fredy Cabral, a fisherman from Assolna, said, “Alteration in climatic pattern though is prevailing and seems to be the main factor behind decline in shellfishes; one should not turn a blind eye at the over-exploitation”.
According to Fredy, over-exploitation is a critical factor behind depletion in shellfish population. Modern practices adopted for harvesting of shellfish disrupts their reproduction cycle. Use of iron tools like sickles not only destroys the spats but also the fish seeds. He asserted that the untraditional method of harvesting is one of the main causes behind decline in number of clams, green mussels and oysters.
Experts in the field of environment conservation have said the Chicalim bay is the home to crustaceans like mud crabs, fiddler crabs, clams, windowpane oyster pistol shrimps and that the water pollution due to falling of metal scraps from old barges and debris is also a cause behind shellfish decline.