NOPR Collection:

Diversity and distribution of seagrasses in Chilika Lagoon: Regional threats and management recommendations

2024-09-01T00:00:00Z

Title: Diversity and distribution of seagrasses in Chilika Lagoon: Regional threats and management recommendations Authors: Rastogi, G; K Tripathy, P; P Dash, S; R Muduli, P Abstract: Studies examining the spatial distribution and abundance of seagrasses are limited in the Indian coastal lagoons. Chilika (Odisha) is the largest brackish water lagoon in Asia which supports the second-largest seagrass meadows in India. A field survey was conducted from 20 locations (n = 57 sites) across the southern, central, and outer channel sectors of the lagoon. A total of six species: Halophila ovalis, H. ovata, H. beccarii, Halodule pinifolia, H. uninervis, and Ruppia maritima were recorded during the study. Halophila ovalis (31 sites) and H. pinifolia (33 sites) showed wide occurrences in the lagoon. In the southern sector, 46 % of sampled sites demonstrated dense seagrasses (> 70 % cover) with all six species present. In the central sector, 45 % of sites showed medium dense seagrass cover (40 – 70 %) and 4 species were recorded. In the outer channel, 94 % of sampled sites supported dense seagrasses represented by 3 species. Seagrass cover showed a significant positive correlation with salinity (r = 0.489, p-value < 0.01) and plant biomass (r = 0.445, p-value < 0.01). The meadows in the southern and central sectors showed profuse growth of Stuckenia pectinata, Najas indica, Gracilariopsis longissima, and Chaetomorpha with seagrasses. Based on DAPSIR (Drivers-Activities-Pressure-State-Impact-Responses) framework, anthropogenic threats to seagrasses included fishing gears, unsustainable fishing methods, including aquaculture, and boat operations. The framework suggested that management responses must include restrictions on fishing gears, illegal aquaculture, and stricter surveillance on boat traffic and water quality. Besides, promoting ecotourism, framing policy actions, stakeholder awareness and community participation were also recognised as crucial responses for effective conservation and protection of seagrasses. Page(s): 595-610

Population characteristics of green tiger shrimp (Penaeus semisulcatus De Haan, 1844), in Palk Bay, Southeast coast of India

2024-09-01T00:00:00Z

Title: Population characteristics of green tiger shrimp (Penaeus semisulcatus De Haan, 1844), in Palk Bay, Southeast coast of India Authors: Rajkumar, M; Lakshmi Pillai, S; Saravanan, R; Thirumalaiselvan, S; K Shoba, J Abstract: Green tiger shrimp (Penaeus semisulcatus), also known as flower shrimp, is one of Palk Bay's most economically productive fisheries. Despite the uniqueness of Palk Bay's fishery, there has been no assessment of the green tiger shrimp's population parameters in the past 3 decades. The current study aims to understand the population characteristics of P. semisulcatus in Palk Bay. For the study, a total of 14,844 individuals of P. semisulcatus were randomly sampled for length frequency analysis between January 2017 and December 2022. The growth parameters were L∞ = 229.3 mm, k = 1.24 y-1 for males, and L∞ = 270.4 mm, k = 1.14 y-1 for females. Mortality parameters and exploitation ratio estimates recorded were Z = 5.301, M = 2.214, F = 3.087 y-1, E = 0.582 for males, and Z = 5.474, M = 2.002, F = 3.265 y-1, E = 0.634 for females. For both males and females, the Ecurr (current exploitation ratio) was higher than the optimum exploitation ratio (E = 0.5), and the Lm50 (length at maturity) was lower than the LC50 (length at capture). This study generates primary information that provides valuable inputs for developing suitable fishery management plans for the resource from the Palk Bay region, potentially leading to its sustainability certification for trade. Page(s): 611-625

An account on the emerging gastropod shell-trap fishery of short-armed octopus Amphioctopus aegina (J. E. Gray, 1849) in Palk Bay, Southeast coast of India

2024-09-01T00:00:00Z

Title: An account on the emerging gastropod shell-trap fishery of short-armed octopus Amphioctopus aegina (J. E. Gray, 1849) in Palk Bay, Southeast coast of India Authors: Rajkumar, M; Thirumalaiselvan, S; Rajkumar, R; Midhun, M; Joseph Jegan, S; Shanmuganathan, K; Saravanan, R; Kavitha, M; K Shoba, J Abstract: Octopuses are bottom-dwelling molluscan species that inhabit both surface and deep waters. Octopuses exhibit camouflaging behaviour and usually hide in the crevices of reefs and rocks. This paper reports the re-emergence of the shell trap fishery for short-armed octopus, Amphioctopus aegina, after four decades in the Palk Bay region, following traditional fishing practices and Fiberglass-Reinforced Plastic (FRP) boats with outboard engines. Fishermen use gastropod shells as their base material. About 3000 – 3500 gastropod shells were tied at one-metre intervals on a 2 mm-thin Polypropylene rope. Amphioctopus Aegina formed 97 % of the landings with an estimated average catch per unit effort ranging from 40 to 50 kg/unit, followed by A. marginatus (2 %), and A. neglectus (1 %). The estimated profit margin is 61.3 %, and the labour efficiency is 20 kg. Page(s): 626-633

Rediscovery of Travisia arborifera Fauvel, 1932 (Annelida, Sedentaria, Travisiidae) in the Parangipettai coastal waters of Southern India

2024-09-01T00:00:00Z

Title: Rediscovery of Travisia arborifera Fauvel, 1932 (Annelida, Sedentaria, Travisiidae) in the Parangipettai coastal waters of Southern India Authors: Chandrasekaran, P; Murugesan, P; Sudhakar, S Abstract: An uncommon species of T. arborifera Fauvel, 1932, has now been reported in the Parangipettai coastal waters through systematic field surveys and taxonomic examination, following a 70-year gap. Fauvel originally described the species in 1932 and 1953 from Indian waters. Afterwards, there have been no records of this species. Updated information on its distribution and morphology, along with a description of T. arborifera at Parangipettai coastal water, is provided in this paper. Page(s): 634-638