|DETAILED STRATEGIES AND ACTION PLANS
During summer, the fish recovers from the growth retardation phase of winter due to increasing temperature in the pond and better availability of natural food. Thus, the arrival of summer is beneficial for inland aquaculture and fisheries in terms fish production. In the open water fisheries, the water level decreases with a corresponding increase in plankton, periphyton and benthos augmenting fish growth. Further, reduced water level increases the catch per unit effort in the inland capture fisheries. However, very high temperature, coupled with critically low water levels can reduce the buffering capacity of water, besides subjecting the fish stocks under stress in the form of high temperature, oxygen depletion and toxicity due to algal blooms. These stresses can affect the fish growth and biomass production and even lead to mass mortality.
During the transition from winter to summer, extremities in precipitation and temperature and other natural calamities such as cyclones, floods and drought are adverse weather scenarios that a farmer confronts with. These will definitely affect fish/shrimp production and the livelihoods of fishers/farmers engaged in the fishing. The general strategies and action plans for different probable adverse weather scenarios in regard to inland, brackish water and marine fisheries, with some emphasis on summer scenarios are given below:
1. INLAND FISHERIES AND FRESHWATER AQUACULTURE
1.1 Pen culture of fish and prawn in derelict water bodies/ lagoons/ lakes/ floodplain wetlands
Shallow areas of derelict water bodies/lagoons/lakes/floodplain wetlands can be made use of for raising table size fishes and prawns in enclosure (pens). After assessing water depth, duration of water availability and seed availability, farmers are advised to erect pens of suitable size and shape, depending on the capacity of water bodies and topography of the area. However, pens of 0.1 to 0.2 ha size is economical and ideal for easy operation. The selected water bodies should have at least 1 m water depth for 3-4 months. Indian major carps, viz., Catla ( Catla catla ), Rohu ( Labeo rohita ), Mrigal ( Cirrhinus mrigala ) and giant freshwater prawn ( Macrobrachium rosenbergii ) are ideal for raising in pens. The pens may be stocked with seeds of Indian major carps at 10-15cm length @ 10,000-15,000/ha and prawn at 6-8cm length @ 20,000-30,000/ha. An average production of 400kg of Indian major carps and 80kg of prawns can be realized from pens of 0.1 ha (1000 sq m) area in four months of rearing. Temporarily increasing the height of pen might become necessary to prevent loss of stock, in the event of sudden rise in water level. Through application of scientific site selection procedure and pen management practices, the farmer can overcome water shortage in the event of sudden drop in water level. Further details of pen culture in open water bodies can be obtained form CIFRI Barrackpore.
1.2 Value -added Fish products
During severe water shortage, farmers might need to harvest fish in large quantities at short notice, leading to difficulties in marketing. Fish and shellfish can be stored in cold storage, dried or used for preparing value added products like pickles, papad, etc. The details of the methods to be followed in post harvest processing can be obtained from CIFT, Kochi .
1.3 Pond management and partial harvesting
Grow-out ponds with 1.5- 2.0 m water depth and having good water holding capacity are ideal for withstanding the temperature shock during summer. In case of ponds with lower water depth, biomass needs to be reduced proportionately through partial harvesting. Since reduced water volume in the pond lowers its buffering capacity against odds, cautious approach should be adopted while using manure and fertilizer in order to avoid algal blooms and eutrophication. Central Institute of Freshwater Aquaculture ICIFA ), Bhubaneswar can be contacted for more details.
1.4 Short-term culture of alternate species
Adverse impacts of the summer spell on pond productivity can be minimized through adoption of short-term (August/September to February/March) culture of species having rapid initial growth. Medium carps like silver barb ( Puntius gonionotus ), Olive barb ( Puntius sarana), Bata ( Labeo bata ) and Labeo fimbriatus are ideal candidates for summer season due to their rapid initial growth and market preference even at smaller size (200- 250 g ). Culture of the minor carp Amblypharyngodon mola is another summer option for utilizing the small shallow ponds. Being an auto-breeder that breeds two to three times in a year, this fish helps in auto-stocking of the pond during summer. On supplementary feed, the biomass increases rapidly. Though low in production, this fish has the advantage of higher market price, besides ensuring utilization of shallow ponds. The technological details are available at the CIFA, Bhubaneswar.
1.5 Stunting of major carp fingerlings
Carp seed rearing in shallow ponds can be extended to the summer season for production of stunted fingerlings. The use of stunted fingerlings has become popular in recent years among fish farmers, since these not only grow faster in grow-out culture phase, but also tacitly extend the culture period through saving the seed raising period from previous year.
1.6 Air breathing fish culture in marshy or swampy areas
Due to scarcity of water, many places become swampy/marshy and non-productive. The farmers are advised to use the technology of air breathing fish culture (freshwater catfishes), which has been developed by ICAR. These fishes grow in shallow ponds and tolerate higher water temperature and thereby sturdy to withstand dry summer spell. The technological details are available with CIFA, Bhubaneswar
1.7 Ornamental fish farming
Ornamental fish rearing is a suitable option for utilization of shallow ponds during summer months. Ornamental fish species like gold fishes, koi carps, guppy, molly, platy and live bearers are common and easy-to-bred and can be grown in shallow ponds during summer. This activity ensures continuous money flow to the farmers.
1.8 Paddy-cum-fish culture
Fishes can be cultivated in paddy fields either simultaneously or in rotation. Paddy fields of any size can be utilized for this, subject to availability of adequate water in time and space. Paddy farmers are advised to grow fish in rice fields, which will help them to use the available water in the fields, generating additional income. Both freshwater and saline fields can be utilized for this. The species suitable for freshwater paddy fields are Catla ( Catla catla ), Rohu ( Labeo rohita), Mrigal( Cirrhinus mrigala ), Bata ( Labeo bata ), Java punti ( Puntius javanicus ), Silvercarp ( Hypophthalmichthys molitrix ) and giant freshwater prawn ( Macrobrachium rosenbergii ). Sea bass ( Lates calcarifer ), Mullets ( Liza parsia, L. tade, Mugil cephalus ), Catfish ( Mystus gulio ) and Tiger prawn ( Penaeus monodon ) can be cultured in fields with saline waters. Fish production @ 500-800 kg/ha from freshwater paddy fields and 400 -1500 kg/ha from saline water paddy fields can be expected in six months. Appropriate field preparation and management practices would help the grower to overcome any water shortage. For further details the farmers can contact Central Rice Research Institute, Cuttack, CIFA, Bhubaneswar and CIFRI, Barrackpore.
1.9 Integrated farming practices
The farmers are advised to integrate fish farming with other activities such poultry farming, piggery, duckery and animal husbandry. Such integrated farming practices enable them to cut down cost on expensive inputs like feed and manure. Fish farmers can also grow other useful agriculture crops like vegetables, mushrooms, coconut and fruits in farm along fish culture. This activity also results in water savings. The details of the methods to be followed in the integrated fish farming can be obtained from CIFA, Bhubaneswar
1.10 Extended carp breeding and seed production
The substantial use of artificial and synthetic hormones for fish breeding and seed production through induced breeding techniques is generally done during the monsoon situations. However, this can be extended well beyond the monsoon and into the early summer season using special breeding techniques. This will enable the fish farmers to breed fish in captivity and produce required amount of seed even after the monsoon recedes. This prolonged breeding is achieved through hormonal treatment and environment manipulation. The technological details can be obtained from CIFA, Bhubaneswar.
1.11 Short-term fish culture and early harvest
After the withdrawal of monsoon, farmers are advised to be alert about sudden water level fluctuations, water shortage or even drought like situations. They might need to adopt the practice of short-term fish culture and early harvest. Normally, 6-8 months are needed to get good fish production and yield. But to cope with adverse situations, it would become necessary to adopt short-term fish culture and early harvest, albeit at a lower yield and profit rates. The details of the technological inputs can be obtained from CIFA, Bhubaneswar .
1.12 Recycling of water for fish culture
In the event of scarcity of water, the farmers can consider the option of re-circulatory system, where the same water is recycled into the ponds for fish culture with desired effects. The technique does not require additional source of water, thus curtailing need for water exchange.
1.13 Judicious utilization of ground water for fish culture
In general, use of ground water is not advised for breeding and culture of fishes and prawns, but during summer, the hatcheries might need to resort to the use of ground water for unhindered seed production and culture activities. However, it is essential that the physico-chemical quality of water is continuously monitored for its suitability. Details of the technological inputs for this can be obtained from CIFE, Mumbai, and CIFA Bhubaneswar.
The contact details of Institutes:
Central Institute of Freshwater Aquaculture (CIFA),
P.O. Kausalyagang; Bhubaneswar – 751 002
Orissa Telephone: (0674) 2465421, 2465446
E- mail firstname.lastname@example.org , email@example.com
Central Institute of Fisheries Education (CIFE)
Jaiprakash Road, Seven Bungalows Versova
Mumbai – 400 061
Telephone: (022) 26363404, 26348223
E- mail: firstname.lastname@example.org , email@example.com
Central Institute of Fisheries Technology (CIFT)
Willingdon Island ; Matsyapuri P.O. Cochin – 682 029
Kerala Telephone: (0484) 2666880, 2667727
Email: firstname.lastname@example.org, email@example.com
Central Inland Fisheries Research Institute(CIFRI)
Manirampore, Barrackpore – 700120
Telephone (033) 25920177, 25921190
2. BRACKISHWATER AQUACULTURE
Brackishwater aquaculture is essentially dependent on the availability of good quality saline water from the sea, creek or backwaters. In states like West Bengal, Orissa and Gujarat, where the tidal amplitude is very high, the supply from the sea will be maintained in the backwaters and creeks even when there is no monsoon. In other areas, where the tidal amplitude is low like in Andhra Pradesh and Tamil Nadu, the bar mouth of the various creeks normally is kept open by the inflow of freshwater only during monsoon. When there is a failure of monsoon, these bar-mouths may not open and lead to scarcity of water in the creek or backwater.
Water and air temperatures are expected to rise during summer months and this will be more pronounced in southern states. These changes could have beneficial impacts with respect to higher growth rate. However, increased water temperatures leads to other associated physical changes, such as shifts in dissolved oxygen levels. These have been linked to more frequent algal blooms and increase in the intensity and frequency of disease outbreaks. During summer months, the availability of water in the creeks reduces especially in states like Tamil Nadu. This will lead to an increase in the salinity of the creek beyond the tolerable limits of the cultured organisms. Changes in precipitation, pH, water temperature, wind, dissolved CO2, and salinity can affect water quality in estuarine and marine waters. The problem of water scarcity and higher salinity is very site-specific with wide variations depending on the tidal amplitude, water current, etc. Any increase in the intensity and frequency of extreme climatic events such as storms and floods may result in significant infrastructure damage. Hence the strategic plans vary according to the conditions of the site. Following are the general guidelines to the farmers to combat the water scarcity and other adverse weather situations in Brackishwater aquaculture farms during summer:
With reference to summer crop, the following guidelines may be followed:
- Culture should be initiated with at least 1 m of water.
- With impending water scarcity, low stocking density should be adopted. Low stocking density will reduce the culture duration to 3-4 months. It is not advisable to start a culture if water cannot be retained at least for a minimum of 3 months.
- Fertilization and manuring should be avoided when there is acute water scarcity.
- Since water exchange will not be possible, feeding should be at the minimum to avoid organic loading in the pond water.
- High salinity levels of above 35 ppt will hamper the growth of the organisms and result in uneconomical cultures.
- When water level goes below 60 cm in the ponds and there is no water to replenish, the shrimps should be harvested.
- Low water level will lead to high temperature regimes in the ponds which will add to the stress of the cultured organisms.
In deeper ponds (> 1 m), thermal stratification can occur with higher temperature near the surface and low temperature towards bottom. High temperatures lead to the formation of ammonia causing degradation of water quality. To overcome thermal stratification and ammonia build-up, aerators should be operated especially during warm and sunny afternoons. This would help to break thermal stratification by mixing warm surface water with cool sub surface water. More details and technological know-how on coastal aquaculture can be obtained from the Central Institute of Brackishwater Aquaculture (CIBA).
- In low tidal amplitude areas, which receive north-east monsoon like Tamil Nadu and South Andhra Pradesh, it is advisable not to go for summer crop because of high temperatures and hyper salinities in May to July. This will result in stress to shrimps and trigger incidence of diseases.
- Stocking of post larvae has to be completed in all areas by the end of February so that the harvest can be completed before the onset of monsoon.
- During February, the salinity of water in most of the areas is low. Shrimp larvae are produced in hatchery waters with salinities of 28-35 ppt, however advanced post larval stages are often stocked in ponds, where salinity is much lower. At the time of stocking, post larvae should be acclimatized gradually to the salinity of pond water so as to reduce stress and mortality. The acclimatization rate should not exceed 1 or 2 ppt per hour.
- Due to high evaporation rate in summer, salt concentration in ponds gradually increases. Salinity may increase to beyond 40 ppt, which can affect the growth of shrimps. Water should be exchanged frequently either by pumps or tidal inflow. The waters with low salinity (2-5 ppt) can be added for reducing the salinity.
- During summer months, there are wide fluctuations in the salinity associated with the sudden heavy rains, which results in heavy mortality. In this situation, the feeding should be controlled to avoid feed waste accumulation on pond bottom soil.
The contact details of the Institute:
Central Institute of Brackishwater Aquaculture (CIBA)
75, Santhome High Road (Near MRC Nagar),
R.A. Puram, Chennai – 600 028
Telephone: (044) 24617523, 24616948, 24618817
3. MARINE FISHERIES
Marine fisheries and mariculture, are adversely influenced to some extent by the environmental changes brought in by the onset of summer. During summer, seawater temperature rises, resulting in high salinity and low dissolved oxygen. Further, the water column becomes thermally stratified and as a result dissolved oxygen level depletes at the sea bottom leading to low fish production. The thermocline will be moderate in normal summer conditions. The availability of fish in the inshore waters is linked to the seasonal variations in the depth of the thermocline. The top layer of thermocline is located at depths of 40- 75 cm during spring. Normally, chlorophyll a is less than 0.5 mg/m 3 and primary productivity is 50 mg C/m 3 in January to April, compared to 2.5 mg C/m 3 and 200 mg C/m 3 during June to September. Fish larvae are low in abundance during December-April in the west coast of India. Increase in temperature during summer, induces faster growth in shrimps but reduces size at first maturity and resulting in low fecundity and low production.
For cage culture operations of fish, the higher temperature is not favorable. Rise in temperature increases the chances of proliferation of pathogens and increases the food conversion ratio (FCR), thereby pushing up the cost of production. However, the growth of seaweed is faster in summer. The mussel culture operations do not face significant problems during summer.
To ensure adequate availability of marine products during such adverse conditions, buffer stock of the marine products may be maintained. This calls for establishing cold chain facilities and maintaining buffer stocks for regulated release by the appropriate agencies. Preparation and storage of processed fish ( e.g., dried fish) can be done as a small-scale village level activity. The details and further information related to above matters can be obtained from the Central Marine Fisheries Research Institute, (CMFRI) Kochi .
The contact details of the Institute
Central Marine Fisheries Research Institute (CMFRI)
P.B. No. 1603, Ernakulam North P.O.,
Cochin-682018. Kerala. Telephone: (0484) 2394798
BROAD STRATEGIES UNDER DIFFERENT SUMMER SCENARIOS
||Timely onset of summer and hot spell
- Carp breeding and fish seed production programmes
- Minimal use of manure and fertilizer in ponds
- Adopting short-term fish culture
- Partial harvest to thin the biomass proportionately to the receding water volume
- Recycling of water for fish culture
||Delay in summer
- Extended carp breeding and seed production programme
- Air breathing fish culture in marshy or swampy areas
- Culture of medium carps
- Extend the carp seed rearing programme to produce stunted fingerlings
- Ornamental fish rearing
||Early withdrawal of summer
- Get ready to start the carp seed production activity in hatchery immediately after first shower or onset of monsoon
- Fish harvest from grow-out ponds and prepare the pond for next crop
- Paddy cum fish culture
- Integrated fish farming activities with holistic approach
||Higher inland water temperatures due to changes in air temperature, increased intensity of solar radiation.
- In northern states, take advantage of warm temperature and optimum conditions for growth by increasing the stocking density within the limits on numbers prescribed by Coastal Aquaculture Authority
||Changes in oceanographic parameters - Reduction in wind velocity, currents and wave action
- Reduced stocking densities to prevent waste accumulation in ponds
||Increase in frequency or intensity of storms
- Avoiding the culture of those species requiring longer DOC. Initiate culture in advance in areas frequently prone to flooding, to prevent the damage to aquaculture infrastructure facilities and loss in production
||Stock loss and low catches
- Maintain buffer stock of marine products to ensure their availability during adverse conditions
||Shortage of fish
- Establish cold chain facilities and maintain buffer stocks for regulated release by the appropriate agencies
||Shortage of fish
- Preparation and storage of processed fish ( e.g., dried fish) as a small-scale village level activity
||Drastic fall in water level in bheels
- Watch water level variations in pens. Harvest fish stock and shift to safe places if water depth in pen falls below 0.75 m
||Extremely high temperature
- Keep vigil against algal blooms in pens
||Low water level in rivers and reservoirs exposing brood stock
- Do not fish in the deep pools and other shallow areas, where brood stocks are vulnerable for over-fishing. Do not fish brood stock. If caught or found in vulnerable places, shift them to deep, safe areas. Do not fish the stocked fingerlings from reservoirs and beels
- Salvage the fish seed /fry in upland streams, home to spawning grounds of valuable cold water fish species to deeper portions of river.
List of fin fishes / prawns / shrimps suggested for use in different States by the fish farmers
Indian major carps
|Labeo rohita (rohu)
||All States of India
|Cirrhinus mrigala (mrigal)
|Catla catla (Catla)
|Cyprinus carpio (Common carp)
|Puntius gonionotus (Silver barb)
||West Bengal, Bihar, Chattisgarh, Some NEH States, Andhra Pradesh, Orissa
|Puntius sarana (Olive barb)
||West Bengal, Orissa ,Bihar, Chattishgarh, Jharkhand, Some NEH States, Andhra Pradesh
||West Bengal, Orissa ,Bihar, Chattisgarh, Jharkhand, Some NEH States, Andhra Pradesh
||Karnataka, Tamil Nadu, Maharastra, Gujarat
||Freshwater marshy and swampy areas of all States
|Macrobrachium rosenbergii (scampy)
||Kerala, Karnataka, Maharashtra, Gujarat, Andhra Pradesh, Orissa, West Bangal, U.P., Haryana, Punjab
|Lates calcarifer (Seabass)
||Kerala, Karnataka, Goa, Maharashtra, Gujarat, Tamil Nadu, Andhra Pradesh
|Mugil cephalus (Mullet)
|Chanos chanos (Milk fish)
||Kerala, Karnataka, Goa, Gujarat, Tamil Nadu, Andhra Pradesh, Maharashtra, Orissa, West Bangal
Source: Weather and Weather Based Crop Management Plan - ICAR
1.1 Pen culture of fish and prawn in derelict water bodies/lagoons/lakes/ ..... Carp breeding and fish seed production programmes; Minimal use of manure and ...