NOPR Collection:

Herpesvirus: An emerging threat to marine turtles

2020-06-29T08:47:59Z

Title: Herpesvirus: An emerging threat to marine turtles Authors: Rao, B M; Sudhan, C; Vikas; Kumari, R; Bedekar, M K Abstract: Marine turtles are long-living reptiles that have a complex lifestyle. They have their attendance all over the globe. The survival of turtles became pathetic due to various activities of human development exercises. Now, on the other hand, emerging diseases came to the platform. Disease indications are alarmingly high in the coastal belts where human activities are higher. Herpesviridae family members are the topmost pathogenic agents that are disturbing the survival of these long-living animals. There are a total of five herpesviruses that are associated with diseases in sea turtles. Fibropapillomatosis is a catastrophic disease caused by herpesviruses, leading to characteristic tumors over the smooth surfaces of the body. Disease had turned out to be an upcoming invader for the marine turtle’s community. The occurrence and hurting potential of the disease depends upon several environmental factors. The current paper provides an evidence of how a simple disease had changed to the burning issue by the influence of adulterated environment during evolution; and a broad overview, clinical marks, and histological studies of remaining reported diseases of herpesvirus in sea turtles. Page(s): 517-526

Passive acoustic metrics to understand shallow water biodiversity off Malvan area in the west coast of India

2020-06-29T08:45:10Z

Title: Passive acoustic metrics to understand shallow water biodiversity off Malvan area in the west coast of India Authors: Chanda, K; Chakraborty, B; Vardhan, Y V; Gracias, D; Mahanty, M M; Latha, G; Fernandes, W; Chaubey, A K Abstract: Underwater soundscape monitoring is an effective method to understand the biodiversity of an ecosystem. In this context, quantitative characterization of shallow water soundscape of the Burnt Island located off Malvan area in the west coast of India (WCI) is carried out. The soundscape characterization involves analysis of the “waveform”, “spectrogram”, and the “power spectral density” (PSD) of the recorded passive acoustic data. Biophonies such as the fish chorus of Terapon theraps, sparse calls of Carangidae along with another unnamed fish species community is reported. Evaluation of the PSDs and corresponding peak frequencies to distinguish the wave-breaking sound and fish species are also covered. Three acoustic metrics namely acoustic entropy (H), acoustic richness (AR), and acoustic complexity index (ACI) of passive acoustic recordings are computed and analyzed to understand their role in relation to fish chorus, wave-breaking, and sparsely available fish sound. Page(s): 527-536

Fishery and stock structure of Thunnus albacares (Bonnaterre, 1788) off Andhra waters along western Bay of Bengal

2020-06-29T08:42:36Z

Title: Fishery and stock structure of Thunnus albacares (Bonnaterre, 1788) off Andhra waters along western Bay of Bengal Authors: Kumar, M Satish; Ghosh, S; Sreeramulu, K; Manjulatha, C; Mahesh, V U; Rao, M V Hanumantha Abstract: The fishery and stock structure of Thunnus albacares off Andhra waters along western Bay of Bengal was studied from 2012 to 2015. The average annual landing of the species during the study period was 5,952 t contributing 32.9 % of the total tuna landings. Gill nets contributed 59 % of the catches, followed by hook and lines (34 %). Von Bertalanffy growth equation was L_t = 196.35 [1 – e^{–0.23 (t+0.0546)}] and natural mortality, fishing mortality and total mortality was 0.4, 0.71 and 1.11 with exploitation ratio of 0.64 and exploitation rate of 0.43. Annual average stock, standing stock biomass and maximum sustainable yield were 13,879 t, 8,383 t and 4,653 t, respectively. Yield per recruit and biomass per recruit estimated were 2584.7 g and 3640.4 g. The exploitation rate, yield and yield per recruit indicate the stock of T. albacares to be overexploited. To sustainably and optimally harvest the species, reduction in the present fishing effort by 60 % is necessary, thereby increasing the yield by 35.31 %. With overcapacity in the number of gillnetters and hook and line units operating in the waters off Andhra Pradesh, implementation of the recommended fleet size proposed by Central Marine Fisheries Research Institute by means of buy-back measures and strict adherence to Minimum Legal Size at harvest would ensure sustainable and optimum exploitation of the resource. Page(s): 537-542

Catch rate and stock status of blue shark in the Pacific Ocean inferred from fishery-independent data

2020-06-29T08:38:58Z

Title: Catch rate and stock status of blue shark in the Pacific Ocean inferred from fishery-independent data Authors: Li, W W; Kindong, R; Wu, F; Tian, S Q; Dai, X J Abstract: Among pelagic sharks, the Blue shark, Prionace glauca (Carcharhiniformes, Carcharhinidae) is known to be the most abundant. Although, blue shark is relatively productive, concerns have been raised related to the decline in population of these apex fish predators; and this decline can affect the marine ecology. This paper presents catch per unit effort (CPUE) data of blue sharks obtained from observers’ on-board Chinese pelagic longline fishing vessels from 2009–2014 in the Pacific Ocean. All the blue shark species were incidentally captured (without shark hook). Nominal CPUE ranged from 0 individual per 1000 hooks to 5.21 individuals per 1000 hooks; the highest annual average nominal CPUE recorded in this study was 0.89 individual per 1000 hooks in 2011 while, 0.58 was the lowest recorded in 2010. Our results equally indicates that, blue shark population was so close to MSY level showing that fishing mortality rate might surpass MSY level in the future, since decrease in catches were observed. Therefore, additional management measures should be implemented in the Pacific Ocean in order to achieve a healthy stock status of this species. Page(s): 543-547