Sustaining Aquatic Ecosystems: Research Efforts for Life Below Water

There is a world beneath the water’s surface which is teeming with life, offering an abundance of consumable food such as fish and other associated resources, including molluscs and shellfish. In the global context, India stands out as a leader in these aquatic resources, and when we turn our gaze to Kerala, we discover a biodiversity hotspot unlike any other. Kerala’s waters are home to a remarkable array of species, with nearly all of India’s aquatic diversity thriving in these vibrant aquatic ecosystems. However, this wealth of aquatic life also presents a challenge – the need for sustainable harvesting and resource management. Recent evaluations of 68 economically significant marine fish species in India have revealed that 86% of these species are currently being harvested in a sustainable manner. The State Fishery Management Plans, meticulously crafted by ICAR-CMFRI, encompass a spectrum of strategies and management alternatives, uniquely tailored to the circumstances of each coastal state. These comprehensive plans encompass measures designed to curtail overfishing attributed to growth and recruitment, incorporating the utilization of non-selective fishing gear alongside external controls for effective regulation. We can look into the innovations such as Minimum Legal Size (MLS) which paved way for a better regulated fishery. One of the most pressing challenges in this effort is maintaining water quality in the coastal and marine ecosystems. Just as climate vulnerability affects marine species in the open sea, similar challenges confront the rivers and lakes of Kerala. To tackle these multifaceted challenges and safeguard both aquatic ecosystems and the well-being of coastal communities, various measures have been in place. Among these initiatives, one of the most noteworthy is the recent emergence of Citizen Science.

One of the primary indicators of water quality is its colour and clarity attributes that can be easily observed and measured. In addition, the quality of water also involves complex interactions with microorganisms and chemical components. CMFRI has made a notable effort to assess and improve water quality through a network of citizen scientists dedicated to preserving a unique tropical lake-estuarine system, the Vembanad Lake, which stretches over 100 km and plays a pivotal role in the livelihoods of approximately 1.6 million people. However, the deterioration of water quality in this vast ecosystem has led to frequent outbreaks of water-associated diseases, causing suffering and, tragically, even loss of life. The establishment of this citizen science network in Kerala was made possible through the active involvement of students from 16 colleges affiliated with three universities in the region, in conjunction with research institutions and various stakeholders. These stakeholders encompass a diverse range of interests, including houseboat owners, nongovernmental organizations (NGOs), inland fishermen, and local residents living near the Vembanad Lake, all eager to contribute to the cause. To assess water colour and clarity, mini Secchi disks equipped with Forel-Ule color scale stickers were employed. Additionally, a mobile application named “TurbAqua” was developed to facilitate the real-time transmission of data. To ensure the quality of the data collected, in-situ measurements by scientists were used to validate a subset of citizen-generated observations. The number of efforts, frequency of observations and colour mapping is provided in the image below.

Providing citizens with the tools and knowledge to assess water quality empowers them to make informed decisions about the water they use, aligning with Sustainable Development Goal 6 – clean water for all. This grassroots approach to monitoring and improving water quality highlights the importance of involving local communities in the stewardship of their own natural resources. In addition to water quality monitoring, CMFRI has also embraced mariculture activities in its coastal regions. Over the past decade and a half, efforts have been made to diversify the livelihood opportunities offered by coastal and marine ecosystems through cage mariculture activities. In India, cage culture is gaining momentum due to its successful and straightforward technology and the abundance of open water bodies. Kerala is no exception, with cage aquaculture becoming a prominent means of livelihood and a profitable venture for many. ICAR-CMFRI has played a pioneering role in advancing mariculture research within India, focusing on the cultivation of marine species in enclosed structures in both inshore and offshore waters. The institute has established hatcheries and grow-out infrastructure to facilitate seed production and has achieved substantial progress in various facets of mariculture. These achievements encompass the development of brood stock, maturation, sex reversal, spawning, fertilization, and hatching for several potential marine finfish species, including cobia, pompano, groupers, snappers, and sea breams. ICARCMFRI has also achieved noteworthy breakthroughs in seed production and the rearing of highly sought-after sea cucumber species. Furthermore, the institute has identified 76 finfish and shellfish species with the potential for mariculture expansion, aiming to bolster seafood exports.

Diverse mariculture technologies, such as coastal and marine cage culture, raft and longline cultivation of bivalves and seaweeds, integrated multi-trophic aquaculture (IMTA), and re-circulatory aquaculture systems (RAS), have been standardized for our aquatic environments. A cage farm from Kannur is shown in the image. Notably, the cultivation of seaweed holds promise as a burgeoning sector, where advancements in culture techniques and post-harvest product development have the potential to substantially elevate domestic seaweed production and related exports. The promotion of molluscan-related farming activities has been a significant focus. This includes spat-based farming activities and hatchery improvement programs aimed at increasing seed production for molluscan farming systems. Recognizing that environmental stress can have profound health implications, we have adopted the globally accepted framework of One Health Aquaculture. This framework encompasses health surveillance and the implementation of antibiotic maximum residue limits (MRL) to ensure the health and well-being of aquatic ecosystems. The increase in harmful algal blooms, a phenomenon known for producing biotoxins, poses another challenge to Kerala’s aquatic ecosystems. On the southern coast, particularly in Calicut, mass mortalities of fish have been observed, indicating the harmful impact of algal blooms on the food chain. To further enhance the study of water quality and address these challenges, citizen science initiatives continue to evolve. Capacity-building efforts are ongoing, with a particular focus on educating and involving the younger generation.