Diversity of fishing gears and crafts used for harvesting the Asian seabass, Lates calcarifer along the Bay of Bengal, Bangladesh coast

Though Asian Seabass, which is locally known as "Koral"/"Vetki," is a vital species in terms of its popularity and price, little is known about the location of breeding and nursery ground, peak breeding season, peak harvesting season, population dynamics, harvesting operation (gears and crafts used for harvesting) of this species in Bangladesh. An investigation was carried out to enlist the group of crafts and gears that are being operated on the Bay of Bengal coast by the fishermen for Asian seabass harvesting. The survey was based on interviews with the local fishermen and secondary data collected from the regional fisheries offices. The study revealed a total of 10 distinguishing fishing gears, including seven nets and two types of hook and lines were used for harvesting this fish. Some are selective for harvesting Seabass, but most of them are involved in multi-species exploitation. Four types of motorized and two types of non-motorized traditional boats are being used for harvesting the seabass in Bangladesh. The seabass fishery extends almost throughout the year at different life stages. The Koral net, Mela Barshi (Single Hook and line), and Push net were found to be effective for catching adult, pre-adult, and juvenile Asian seabasses, respectively. The Sampan boat and Mela barshi were reported for the first time as fishing boats and fishing gear in Bangladesh.

Spatial and Temporal Variations in Sea Level Extremes along the Bay of Bengal Coast

<p>The low-standing Ganges-Brahmaputra-Meghna delta is extremely sensitive to sea level variations induced by tropical cyclones, monsoons and, on the long term, by absolute sea level changes. Moreover, the region is subject to land subsidence, due to groundwater extraction and sediment deposition, which increases vulnerability of coastal populations. Understanding of sea level variability due to the climate change, geological processes, and human activity, is essential for anticipating consequences of extreme events in the nearest future and implementing adequate adaptation strategies. This study analyzes impact of the sea level rise in the Bay of Bengal on the sea level extreme levels and its consequences for extension and frequency of delta flooding. We analyze sea level variations from tide gauges along the coast from 1970 to 2020. By employing advanced statistical methods, our study focuses on interactions between sea level variations (from seasonal to interannual changes) and storm surges generated by tropical cyclones in this specific region. While the analysis is performed over the whole Bay of Bengal coast, a particular attention is given to the low-lying Bangladesh's coastal area.</p>

Pseudanthias vizagensis, a junior synonym of Pseudanthias pillai Heemstra & Akhilesh, 2012 (Perciformes: Serranidae)

Pseudanthias vizagensis Krishna, Rao and Venu, 2017 was described from 44 specimens, collected from Visakhapatnam (Andhra Pradesh), on the Bay of Bengal coast of India, but without clear designation of a holotype. The characters used for differentiating the species from its nearest congener Pseudanthias pillai Heemstra & Akhilesh, 2012, a species currently known only from the northern Indian Ocean, were limited, poor and substantially overlapping. Examination of additional material of P. pillai from the Arabian Sea, Bay of Bengal, Andaman Sea, and comparison with the original description and images of P. vizagensis revealed that the latter is a junior synonym of P. pillai. Diagnostic characters are reviewed, additional morphological details and fresh colouration, including sexual dimorphic characters not covered in previous works are provided.

Seasonal Dynamics of Heavy Metals in Commercially Important Marine Fish from the Bay of Bengal Coast of Bangladesh

This study was conducted to know the seasonal dynamics of heavy metal (Zn, Cu, Cr, Cd, Pb and Hg) concentrations in marine fish from the Bay of Bengal coast of Bangladesh in pre-monsoon, monsoon and post-monsoon seasons. The fish samples of various species viz. Churi (Trichiurus lepturus), Loittya (Harpadon nehereus), Ilish (Tenualosa ilisha) in St-1; Churi, Loittya, Ilish, Surma (Euthynnus affinis) in St-2; and Poa (Otolithoides pama), Loittya, Ilish in St-3 were collected seasonally from fish landing stations during December 2017 to November 2018. The samples were analyzed by using UNICAM-929 atomic absorption spectrophotometer following AOAC (2012) in the Food Laboratory of the SGS Bangladesh Limited., Dhaka. The results showed that among the metals, only Zn was detected in every station over the seasons. Overall metal accumulation, Zn content found more followed by Cu and Cr, whereas Cd, Pb and Hg were below the lower limit of detection in all the collected fish samples. Therefore, the study concluded that the fish are safe for human consumption as well as for public health and food safety measures ensured by common marine fish of Bangladesh.

Length-weight relationship and population dynamics study of the giant catfish (Arius thalassinus) in the Bay of Bengal coast of Bangladesh

The present study investigated the length-weight relationship, population parameters and the instantaneous natural mortality rate of Arius thalassinus from two major landing center of Bangladesh using the FAO-ICLARM Stock Assessment Tools (FiSAT II). A total of 1789 specimens were collected between January 2016 and December 2017. The estimated values of the exponent “b” was ranged from 3.019 (pre-monsoon) to 3.293 (monsoon), indicating an isometric growth pattern of the species with high correlation coefficients (0.904 to 0.927). The equation of length–weight relationship was: W=0.005L3.181. Model parameters of the von Bertalanffy growth equation were: L∞ = 97.60 cm and K = 0.33-1 year. The estimated growth performance index (Ø) was 3.497. The instantaneous natural mortality rate (M) was 0.62-1 year and a high exploitation rate (E) 0.62 (>0.50) showed that this fish is over-exploited in the Bay of Bengal coast of Bangladesh. Res. Agric., Livest. Fish.6(3): 439-444, December 2019