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Subsistence fishery for cephalopods contributes significantly to the local economy of several Asian, African and island states. In addition to being unregulated and undocumented, recent studies indicate that low-scale fisheries can have detrimental effects on marine ecosystems. In the Lakshadweep islands, men, women and children have been involved in spear fishing for octopus for a long time, but there is a paucity of information on the biology and fishery of the octopus species in Indian waters. In this study, we estimated the population abundance, morphometry and sex ratio of Octopus cyanea. Moreover, we examined whether the current octopus spear fishing activity displayed size or sex selectivity, given that larger individuals are easier to spot and brooding females spend more time in crevices. O. cyanea surveys were conducted by snorkeling in the lagoons of Kavaratti and Agatti islands between November 2008 and April 2012. The estimated mean density of O. cyanea was 3 and 2.5 individuals per hectare in Agatti and Kavaratti, respectively. Individual mean weight was 923.36 g and 846.26 g in Agatti and Kavaratti and the male:female sex ratio 1.35:1 and 3.8:1, respectively. Comparison between visual counts and fisheries landings indicated that fishing effort was concentrated in areas of high juvenile abundance but without female-bias. Constructing a long-term database of fishery catches will help with stock assessment and understanding the factors that influence octopus populations. Implementation of a lower size limit of 500 g would act as a precautionary measure against catching very small octopuses.

Summary: Bustards comprise a highly threatened family of birds and, being relatively fast, heavy fliers with very limited frontal visual fields, are particularly susceptible to mortality at powerlines. These infrastructures can also displace them from immediately adjacent habitat and act as barriers, fragmenting their ranges. With geographically ever wider energy transmission and distribution grids, the powerline threat to bustards is constantly growing. Reviewing the published and unpublished literature up to January 2021, we found 2,774 records of bustard collision with powerlines, involving 14 species. Some studies associate powerline collisions with population declines. To avoid mortalities, the most effective solution is to bury the lines; otherwise they should be either routed away from bustard-frequented areas, or made redundant by local energy generation. When possible, new lines should run parallel to existing structures and wires should preferably be as low and thick as possible, with minimal conductor obstruction of vertical airspace, although it should be noted that these measures require additional testing. A review of studies finds limited evidence that 'bird flight diverters' (BFDs; devices fitted to wires to induce evasive action) achieve significant reductions in mortality for some bustard species. Nevertheless, dynamic BFDs are preferable to static ones as they are thought to perform more effectively. Rigorous evaluation of powerline mortalities, and effectiveness of mitigation measures, need systematic carcass surveys and bias corrections. Whenever feasible, assessments of displacement and barrier effects should be undertaken. Following best practice guidelines proposed with this review paper to monitor impacts and mitigation could help build a reliable body of evidence on best ways to prevent bustard mortality at powerlines. Research should focus on validating mitigation measures and quantifying, particularly for threatened bustards, the population effects of powerline grids at the national scale, to account for cumulative impacts on bustards and establish an equitable basis for compensation measures. [ABSTRACT FROM AUTHOR]

The jumping spider species Plexippus minorWesołowska & van Harten, 2010, known from the United Arab Emirates is here reported from India, from the Desert National Park Wildlife Sanctuary in the state of Rajasthan. Detailed redescriptions with high quality illustrations of both Indian and type specimens of P. minor, including 3D models of the type, are presented, and the distribution is updated. This work increases the number of Plexippus species in India to seven. [ABSTRACT FROM AUTHOR]

Highlights: [•] Can strategic allocation of agro-pastoral landuses save threatened grassland fauna? [•] Florican and lizard numbers modeled on crop-cover and grazing intensity. [•] Contrasting choice of moderately tall (florican) vs. short (lizard) grassland. [•] Interspersed cropland and spared pasture (rotationally) optimized conservation. [•] Subsidized food rationing to curtail production rise in conservation areas proposed. [ABSTRACT FROM AUTHOR]

Compounding effects of slow life-history traits and adult-specific overharvesting have caused a range-wide decline of several giant clam populations. Erratic changes in these populations reported at isolated reefs, are attributable to stochastic fluctuations in recruitment and survival rates. These population rate parameters may be adversely influenced by the considerable and increasing human-reef economic interactions in tropical waters. The unsubstantiated knowledge on such influences hinders conservation management of species-habitat linkages particularly for species like the small giant clam (Tridacna maxima). Our study reports small giant clam survival rate, its ecological determinants and stochastic fluctuations from shallow lagoon waters of Lakshadweep Archipelago; a natural habitat not subjected to commercial giant clam harvesting. Survival rate was estimated by monitoring the status of identified individuals in belt-transects through successive years 2005-2009. The role of different factors in explaining the variation in survival rates was investigated at relevant scales: anthropogenic pressure at the population level in the reef, clam density at sub-population level in the belt-transects, and variables related to clams at the individual level. Effects were quantified through univariate regression techniques and Kaplan-Meier estimator coupled with generalized linear (logit link) models. Small giant clam survival rate in the reef decreased and its spatio-temporal fluctuations increased along the increasing gradient of human populations. Survival was density-independent. Size/age specific survival followed Siler distribution characterized by very low early-age survival, increased adult-age survival, and low older-age survival. Anchorage in coral substrate exerted a curvilinear effect, where survival of moderately anchored clams > loosely anchored clams >> deeply embedded clams. Our study recommends regular population monitoring in densely inhabited islands to detect incipient changes, which can subsequently be confronted by scientific lagoon bed management. [ABSTRACT FROM AUTHOR]

Giant clams are endangered in many parts of their Indo-Pacific range owing to adult specific overharvesting that threatens recruitment, a demographic parameter exhibiting high sensitivity to environmental disturbances and adult densities among tridacnids. Lakshadweep reefs are not subjected to commercial giant clam fishery, and population assessment has not been carried out in these waters so far. We monitored the small giant clam Tridacna maxima populations in confined waters of 12 reefs in Lakshadweep Archipelago during 2005-2007 using a systematic line transect based distance sampling framework. Overall T. maxima density in the Archipelago was estimated at 141.2/ha (95% CL 118.2-168.7) in 2005 and 122.7/ha (103.60-145.37) in 2006. Populations showed wide variation in densities and relative proportions of different age-classes between reefs. While Agatti, Bitra and Chetlat lagoons harboured high clam densities, Amini harboured the most impoverished population. Data simulation showed that total clam count along transects of 100 m length x 2-5 m strip width, in a minimum of 140 replicates, stratified by area among lagoons, would provide a viable monitoring index for rapid assessments of T. maxima in Lakshadweep. Compared to unbiased absolute abundance estimates, this monitoring index could be achieved more easily, without much compromise on accuracy and precision, necessary for meaningful spatio-temporal comparisons. [ABSTRACT FROM AUTHOR]

Electricity supply lines through wildlife habitats can adversely affect biodiversity, yet lack of evidence impedes their mitigation in tropical developing countries. We assessed power line induced bird mortality in 4200 km2 area of the Thar desert, India during 2017–18. We searched for carcasses in 2000 × 60 m2 belts along 40 randomly selected power lines over six multi-season surveys, and in 20 control transects that were surveyed once. We experimentally corrected for count biases by estimating persistence and detection probabilities of 88 fresh carcasses, using Kaplan-Meier survival analysis and binomial GLM, respectively. Scaling mortality by power line crossings of bird families, we examined the influence of group traits on vulnerability, using GLM. We examined the effect of power line mortality on population viability of the Critically Endangered great Indian bustard. We found 289 carcasses of >40 species at power lines and none at control transects. As expected, carcass persistence time and detectability were lower for small birds (<100 g) than large birds (>1000 g). Bias-adjusted mortality was estimated at 3.05 carcasses (95% CI 0.82–6.03) and 5.97 (2.5–10.50) carcasses km−1 month−1 for <33 kV and ≥33 kV lines, respectively. Mortality was positively related to number of wires. Large-bodied and ground-dwelling families were most vulnerable to power line mortality. We estimated 87,966 (SE 25,701) bird mortalities per year in the study area. These findings bear global conservation implications since the Thar desert supports 14 Threatened and 65 migratory species of the Central Asian Flyway. The population viability analysis revealed that the great Indian bustard is at imminent risk of extinction due to power line mortality, and calls for urgent mitigation of overhead power cables and the avoidance of future overhead installations in bustard habitat. • Comprehensive assessment of power line induced bird mortality in the Indian Thar desert. • Overhead wires transmitting renewable power an important threat to bird conservation • Large, ground-dwelling birds particularly vulnerable • Imminent extinction risk of critically Endangered great Indian bustard if power lines are not buried. [ABSTRACT FROM AUTHOR]

• One of a kind long-term Tridacna maxima population study, spanning 14 years. • Study was preceded by one & intercepted by two El Niño events (1998, 2010 & 2016). • SST anomalies triggered bleaching but did not cause immediate clam mortality. • Population change rate was influenced by time since bleaching. • Climate change-induced frequent SST anomalies affects viability of giant clams. Frequent sea surface temperature (SST) anomalies may have global consequences on marine biodiversity conservation through their potential impacts on fragile coral reefs and associated organisms such as the giant clams. However, effects of SST anomalies on giant clam population dynamics is not clearly understood as their slow life-history traits require long-term population studies for unravelling these patterns. Here, we have examined the effects of SST anomalies on Tridacna maxima by monitoring their populations in Lakshadweep archipelago across a 14 year period (2004–2017). We monitored T. maxima density annually in three reefs (Agatti, Bangaram-Tinakkara and Kavaratti) using 100 m × 8 m belt transects. The annual patterns of density change rate (λ t) against time since bleaching were modelled and used to develop stochastic population growth models under different scenarios of bleaching incidence. Our study was preceded by one and intercepted by two El Niño events (1998, 2010 and 2016). Mean summer SST > 30 °C triggered T. maxima bleaching. Population density showed large inter-annual variations that were synchronous between reefs, showing gradual increase in density during 2004–2010, and decrease during 2010–2017. SST anomalies did not cause immediate clam mortality. However, T. maxima population change rate (λ) was 0.91 ± 0.05 SE immediately after bleaching and increased by 0.02 ± 0.01 SE per year, resulting in positive growth only after five years since bleaching. Time-series analysis of SST data (1965–2016) indicated increasing incidence of anomalous temperature (β = 0.09 ± 0.04 SE). Population growth models showed stable density trend after 50 years under past bleaching incidence (20% yr−1), but declining density (R = −0.05 ± 0.02), high risk of quasi-extinction (0.31–0.61 across reefs), and low density (geometric mean: 9–15 individuals ha−1 across reefs) under the prevailing high bleaching incidence (40% yr−1). Thus, climate change induced frequent SST anomalies are likely to compromise the viability of giant clam populations. [ABSTRACT FROM AUTHOR]

Ectotherms are particularly vulnerable to climate change, especially those living in extreme areas, such as deserts, where species are already thermally constrained. Using the vulnerable herbivorous lizard Saara hardwickii as a model system, we used a multi-pronged approach to understand the thermal ecology of a desert agamid and potential impacts of rising temperatures. Our data included field-based measures of operative temperatures, body temperatures, and activity, as well as lab-based measures of thermal limits, preferences, and sprint speed. As expected, the temperature dependence of locomotor performance and foraging activity were different, and in the worst-case global warming scenario (SSP5-8.5), potential sprint speed may decrease by up to 14.5% and foraging activity may decrease by up to 43.5% by 2099. Burrows are essential thermal refuges, and global warming projections suggest that S. hardwickii may be restricted to burrows for up to 9 h per day by 2099, which would greatly limit critical activities, like foraging and seeking mating opportunities. Overall, we show that key information on thermal ecology, including temperature-sensitive behaviours in the wild, is necessary to understand the multiple ways in which increasing temperatures may influence ectothermic vertebrates, especially for species like S. hardwickii that are already vulnerable to environmental change., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2024. Published by The Company of Biologists Ltd.)