Current Science Reports
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NEWS Current Science Reports Assessing Coral Bleaching Increasing ocean temperatures of entanglement,’ says Hina Khatoon, Sensing sea-surface temperature speed up development in fish. Wildlife Institute of India. How does this affect fish larvae dis- Fishing is a major occupation in The Malvan marine sanctuary in persal? nearby villages. The researchers Maharashtra is rich in corals. These Rohan Arthur, Nature Conservation found that the fishers were not aware colourful animals are indicators of Foundation, Mysuru collaborated with of fisheries regulations and proper marine ecosystem health. From 2014 researchers from Spain to find out. gear disposal. to 2019, Baban Ingole and team from The team sampled around 1500 ‘Ineffective regulations worsen the CSIR-NIO, Goa have been conducting individuals representing 9 common situation,’ says Sumit Kumar, Wildlife underwater surveys. Over the period, species in the Mediterranean Sea. To Institute of India, Uttarakhand. there was an alarming decline in coral understand early life traits – growth The economic condition of fishers colonies. rate, settlement size, hatching and prevents purchasing better gear. And settlement dates – they counted low quality gear deteriorates rapidly. growth rings in the otolith, a structure ‘With better environmental aware- in fish ears which produces growth ness and if fishing boards provide rings annually. better gear cheaper, the problem of How long the larvae stay near the plastic in the Ganga might shrink,’ surface before settling to the bottom says Aditi Dev. determines how far they disperse. DOI: 10.1016/j.scitotenv.2020.143305 The data helped the researchers predict how changes in temperature Microplastic Pollution affect larval stages from hatching to Macro pollution in Marina Beach Image: Kalyan De settlement and influence their ability Microplastics are less than 5 millime- Monitoring the condition of corals in to disperse. tres in size. We ingest around 30 such turbid seas is difficult and underwater Nearly all species showed a de- particles everyday through sea salt surveys require resources. So the cline in surface larval displacement alone. They cause nervous and repro- team decided to try satellite data for with increase in temperature. They ductive disorders, and even cancer. the purpose. Collaborating with re- grew quicker and settled down. We need to understand microplastic searchers from the Punjab Remote Reduced population dispersal and waste better to manage the menace. Sensing Centre and the Kuwait Insti- contraction of ranges may isolate fish Recently, researchers from Pachai- tute for Scientific Research, they populations. This can impact fisheries yappa’s College, Chennai, and Bhara- measured thermal stress on corals in and marine ecology and evolution, thidasan University, Tiruchirappalli the eastern Arabian Sea. say the researchers. collaborated with researchers from In 2015, sea-surface temperature DOI: 10.1111/1365-2656.13435 Japan and France to investigate rose to a record level. A 12-week microplastic waste from Marina beach, cumulative measure of thermal stress Ghost Gear in Ganga in Chennai. remained above threshold levels from Threat to biodiversity They processed samples from sea 2014 on, peaking in 2016. Ghost gear, discarded fishing equip- water, and wet and dry sand along a ‘When stressed, corals expel symbi- ment in water bodies, traps aquatic 5 kilometre stretch. There were 250 to otic microalgae. The algae provide animals. Ruchi Badola and team from 400 microplastic particles per kilogram nutrition and energy. Without them, the Wildlife Institute of India, Dehra- of sample. Under a microscope, most corals turn pale and die,’ explains dun set about identifying the sources microplastics were like filaments. Baban Ingole. of ghost gear in the Ganga, in col- Some were like granules. ‘Satellite sea surface temperature laboration with researchers from ‘The number of microplastics here is data is cost-effective to monitor coral Bangladesh and the UK. almost twice what is found in Mumbai, reefs and predict bleaching,’ adds his The team selected nine locations Tuticorin or Dhanuskodi beaches,’ colleague, Kalyan De. along the river, ranking them based says S. Venkataraman, Pachaiyappa’s DOI: 10.1080/10106049.2021.1886345 on gear density. Ghost gear in- College. creased in the river as it flowed to- The team found that most were Increasing Ocean Temperatures wards the Bay of Bengal – remnants polyester or polyfluoride compounds. Isolating marine assemblages of plastic nets, some with mesh sizes Polyester is a commonly used syn- Most marine fish have a biphasic life that are illegal. thetic textile and polyfluoride is used in cycle. They spend their early life as Air breathing aquatic animals are electric batteries, food processing and free swimming larvae near the surface, the most affected. packaging. Synthetic textiles, domestic dispersing through phytoplankton, and ‘Turtles, otters and the endangered water and fishing material are major settle to the bottom after maturity. Ganges river dolphin are at high risk sources of microfilament plastic. CURRENT SCIENCE, VOL. 120, NO. 6, 25 MARCH 2021 975 NEWS Banning plastic bags is not enough What is the long-term impact of biological and chemical oxygen de- to stem the microplastic menace. plantation forests on species composi- mand, making it inhospitable to aquatic DOI: 10.1016/j.scitotenv.2020.144073 tion, plant diversity and carbon storage life. potential? How do these differ from ‘Such conditions affect livelihoods. Wildlife Behaviour those in natural forests? The long-term impact might be irre- Temporal interaction Anudip Gogoi and colleagues from versible,’ adds Indrajit Mandal. the Mizoram University, Aizawl set out The report is a wake-up call to use Fear of predators drives temporal pat- to explore. The team used the same environment-friendly technologies for terns in prey. Chances of detecting sampling technique in a 39-year-old stone mining and crushing. prey determine carnivore activity. But plantation forest and a natural forest in DOI: 10.1080/10106049.2019.1597390 these patterns are not rigid. Subtle the Brahmaputra flood plains changes in niche regulate the ecosys- In the natural forest, species domi- tem. Indian King Prawn Farming nance and evenness were higher. As Urjit Bhatt and team from the Wildlife Loss due to infections were plant biomass and carbon stocks. Institute of India, Dehradun set up About 70% of export revenue from But, in the plantation forest, biodi- sensor-based cameras to document sea food is from the king prawn, Lito- versity indices were greater. Tree spe- animal activity patterns in Manas penaeus vannamei. However, dis- cies richness was slightly higher. The National Park, Assam. eases cause major losses for aqua number of herb species was three The team found that smaller carni- farmers in India. times higher. vores foraged at night, those of me- Recently, scientists from the ICAR- ‘Plantation forests reduce human dium-size were nocturnal or diurnal Central Institute of Brackishwater pressure on natural forests and create and large animals were active as and Aquaculture, Chennai, the Navsari livelihoods for associated communi- when they needed food or water. Agriculture University, Gujarat and ties,’ says Anudip Gogoi. ‘Body size seems to decide active the West Bengal University of Animal ‘Plant forests in degraded lands to periods,’ explains Urjit Bhatt, Wildlife and Fishery Sciences calculated the sequester carbon,’ suggests Jitendra Institute of India. economic impact of diseases in king Ahirwal, his colleague. How do related carnivores avoid prawn farming in India. ‘Sustainably manage such forests to conflict? By overlapping the temporal They conducted surveys in Tamil conserve biodiversity,’ recommends patterns of the animals, the research- Nadu, Andhra Pradesh, West Bengal, Uttam Kumar Sahoo. ers found that, though similar carni- Maharashtra and Gujarat, covering DOI: 10.1016/j.jenvman.2020.111671 vores hunt at the same time, they about 90% of the farming area. avoid competition in subtle ways. For To estimate employment loss due Stone Mining Deteriorates example, clouded leopards avoid to reduction in culture duration, the Dwarka river basin tigers by climbing trees. team interviewed more than 900 Besides day, night or twilight, lunar The Dwarka river basin in eastern shrimp farmers. phases also impact wildlife activity. India has huge reserves of building Economic loss for each farm was There was a strong correlation bet- stones. Stone mining and crushing are calculated based on selling price for ween moon phases and foraging. To common there. Recently, Swades Pal each size group. avoid predators and search for food, and Indrajit Mandal from the University Infection by Enterocytozoon hepa- smaller prey species are more active of Gour Banga, West Bengal exam- topenaei, a parasite, and white spot on brighter nights. But their predators, ined how these activities impact the syndrome virus accounted for most small carnivores, are active on darker environment. losses. Enterocytozoon hepatopenaei nights. Noise levels at mining and crushing infections caused an annual loss of ‘The risk of competition and preda- sites were almost a hundred decibels about 2700 crore rupees and the tion creates these temporal activity higher than safe for humans. From white spot syndrome virus, 1200 partitions,’ says Salvador Lyngdoh, satellite data, they discovered that sur- crores. Wildlife Institute of India. face temperature at the sites was up