Ghost fishing capacity of lost experimental gillnets: a preliminary study from Indian waters.

Abandoned, lost, or otherwise discarded fishing gear contributes considerably to global marine debris. These lost gears, mostly made of non-biodegradable synthetic materials, persist in the marine environment for longer periods of time and pose a great threat to marine life by entangling and killing target fishes and other non-target species such as turtles, birds, and mammals, a phenomenon known as ghost fishing. Other environmental impacts include physical impacts on aquatic habitats, transfer of microplastics into food web, and interference with fishing. Information regarding the catching efficiency and catch rates of lost nets in Indian waters is lacking. Ghost fishing capacity of simulated lost gillnets is being reported for the first time in India. This study investigates the ghost fishing capacity of lost gillnets through an experimental approach at Aroor, Vembanad lake, Kerala, India. Simulation studies using purposefully abandoned shrimp gillnets (32 mm mesh size) were conducted to understand the fishing capacity of lost gillnets during two seasons (monsoon and post-monsoon) as separate experiments. The gillnets maintained their catching efficiency until the 15th day during the first experiment and up to the 50th day in the second experiment. Catches showed an exponential reduction over time in both experiments. A total of 251 specimens comprising of 27 species were caught from both sets of experimental nets, and the state of catch in the nets showed different decaying stages from the second day itself along with fresh stages. As the days progressed, particulate matter and detritus began to accumulate on the experimental nets, increasing net visibility and reducing their catching efficiency. The results of the study on ghost fishing capability will contribute to the development of strategies for reducing the effects of lost nets on the aquatic ecosystem and for suggesting improved management strategies.

Microplastics in the edible tissues of shellfishes sold for human consumption.

Microplastics in seafood are an emerging area of seafood safety concern. In this study, we investigated the presence of microplastics (100 µm - 5 mm) in the edible tissues of four species of shellfishes - two species of shrimp, Metapenaeus dobsoni and Fenneropenaeus indicus; one species of crab, Portunus pelagicus; and one species of squid Uroteuthis (Photololigo) duvaucelii -all bought from fishing harbours of Kerala, India. An average of 2.7 ± 12 microplastic particles kg-1 of edible tissue (wet weight) and 0.07 ± 0.3 microplastic particles/individual were obtained from the sampled shellfishes. No microplastics were found in the edible tissues of shrimps examined, while U. (P) duvaucelii had the highest microplastic content with an average of 7.7 ± 20 microplastic particles kg-1 of edible tissue, followed by P. pelagicus with an average of 3.2 ± 10 microplastic particles kg-1 of edible tissue. There was significant species variation in the microplastic contamination of shellfish soft tissues (p < 0.05). The study is the first of its kind to report the detection of microplastics in edible tissues of a squid species. Results suggested an annual dietary intake of about 13 ± 58 microplastic particles per year by shellfish consumers, which can vary based on the species, quantity, and extent of gut removal of seafood consumed.

Microplastics in the edible and inedible tissues of pelagic fishes sold for human consumption in Kerala, India.

Microplastics in commercially important seafood species is an emerging area of food safety concern. While there have been reports of plastic particles in the gastrointestinal tract of several species, presence of microplastics in edible fish tissues has not yet been reported from India. This study examined the presence of microplastics in the edible (muscle and skin) and inedible (gill and viscera) tissues of nine commercially important pelagic fish species from Kerala, India. A total of 163 particles consisting mainly of fragments (58%) were isolated. Out of 270 fishes analysed (n = 30 per species), 41.1% of the fishes had microplastics in their inedible tissues while only 7% of fishes had microplastics in their edible tissues. The quantity of microplastics in inedible tissue was significantly larger in filter feeders than, that in visual predators (p < 0.05). The average abundance of microplastics in edible tissues was 0.07 ± 0.26 items/fish (i.e., 0.005 ± 0.02 items/g) and was 0.53 ± 0.77 items/fish (i.e., 0.054 ± 0.098 items/g) in inedible tissues. The results suggest the possibility of human intake of microplastics by the consumption of pelagic fishes from this region, albeit in small quantities.

Abundance, characteristics and seasonal variation of microplastics in Indian white shrimps (Fenneropenaeus indicus) from coastal waters off Cochin, Kerala, India.

The microplastic contamination of seafood species is increasingly becoming a global concern due to its potential influence on food safety and human health. This study investigated the presence and seasonal variation of microplastics in a commercially important marine shrimp species, Fenneropenaeus indicus, from the coastal waters of Cochin, India. The soft tissues of 330 shrimps were examined over a period of 12 months, from March 2018 to February 2019. A total of 128 microplastics were detected, of which 83% were fibres. An average (mean ± SD) of 0.39 ± 0.6 microplastics/shrimp (0.04 ± 0.07 microplastics/g wet weight) was obtained from the shrimps sampled. Microplastic contamination was significantly higher in July-August (Monsoon season) compared with other months. This study reports microplastic contamination in F. indicus for the first time. Results also suggest that consumption of peeled but undeveined or whole dried white shrimps can be one of the ways of the human uptake of microplastics, especially during the monsoon season.

Assessment of fishing-related plastic debris along the beaches in Kerala Coast, India.

An assessment of quantity, composition and seasonal variation of fishing-related plastic debris was conducted in six beaches along the Kerala coast of India during 2017-2018. Plastic items were the most dominant type of waste constituting 73.8% by number and 59.9% by weight. In the total debris recorded, 5540 pieces (36%) weighing 198.4 kg (39.8%) were fishing related trash. On an average 14.4 ±â€¯12 fishing related items/100 m2, corresponding to mean weight of 0.55 ±â€¯0.7 kg/100 m2 was recorded from these beaches. Results indicated that the fishing-related plastic items were concentrated four times more in the beaches with higher fishing intensity, as compared to the other beaches. Also, the concentration of fishing-related plastic was recorded higher in the post-monsoon season compared to the lowest during monsoon, which was significant with p-value < 0.05. The results emphasize the role of fishing activities in the generation of marine litter.