Remarkable landings of Unicorn leatherjacket

The Unicorn leatherjacket (Aluterus monoceros), belonging to the family Monacanthidae, is found worldwide in subtropical oceans between latitudes 43° N and 35° S, often at depths as low as 50 meters. This fish is identified by its extremely compressed body and the positioning of its eyes towards the back of the head, resulting in both dorsal and ventral head profiles being convex

Captive rearing of Indian mackerel and Indian oil sardine

In the aquaculture industry, candidate species have been successfully domesticated, bred, and raised in captivity, leading to more sustainable and controlled production. However, the success of domestication efforts depends on various factors, including the biological characteristics of the species, environmental conditions and the availability of suitable feed. Indian mackerel (Rastrelliger kanagurta) and Indian oil sardine (Sardinella longiceps), are important commercially harvested species in the Indian subcontinent. Challenges in reproducing the natural conditions for these species, their specific breeding behaviours, and nutritional requirements are barriers to their successful domestication and captive breeding

Fishery and reproductive biology of the spotted sardinella, Amblygaster sirm (Walbaum, 1972) exploited along the southern coast of India

The study focused on the fishery and biological aspects of the spotted sardinella Amblygaster sirm (Walbaum, 1972) exploited along the southern coast of India from 2015 to 2020. The summary of the fishery reveals noticeable annual fluctuations in landing, with peak landings reported from November to March along the coast. The study included fish with total length (TL) ranging from 149 to 208 mm in males and 152 to 217 mm in females. The peak in gonadosomatic Index (GSI) in January indicates its spawning season, and Lm50 was estimated at 172 mm TL in females. The sex ratio (F: M) was determined at 1:1.2, with males dominating most months. Fecundity ranged from 11632 to 43200 eggs per spawning. Five stages of maturity in A. sirm were identified through external analysis of gonads. Seven histological ovarian stages of A.sirm were recorded, providing a primary reference for future studies. These findings aim to assist fishery managers and policymakers in adopting effective management practices for the sustainable harvesting of this resource

Megamouth shark reported from Indian waters

The first confirmed report of Megachasma pelagios (Lamniformes: Megachasmidae) from Indian waters based on a juvenile male shark that landed at Thengaipattinam landing centre, Tamil Nadu, India on 25th April 2022 by a multiday gillnetter cum longliner operated off south of Thengapattinam is given. The shark measured 280 cm in total length and weighed 48 kg

Insight into the fishery, biology and population dynamics of Auxis rochei (Risso, 1810) along the south-west coast of India

Auxis rochei is one of the coastal tunnies contributing substantially to the tuna landings in India, with an average (2014-2019) annual catch of 7210 t. Kerala stood first, with an annual average landing of 3176 t. The fishery comprised 14.5 - 39.6 cm fork length (FL) size groups with a mean length of 27.64 cm and a major mode of 26 cm FL. The Length-weight (L-W) relationship of pooled fishes was expressed as W= 0.000003 L3.22 (r2= 0.91). The size at first maturity was estimated at 25.8 cm FL when the fish was 1.5 years old. The number of eggs per spawning ranged from 84,562 to 1,33,698 and the ova diameter ranged between 0.1 and 0.6 mm, indicating asynchronous oocyte development with multiple spawning. Higher gonadosomatic index (GSI) was recorded during April, May and June and coincided with the minimum gastrosomatic index (GaSI). The recruitment pattern was bimodal, with varied intensity ranging from 0.79-17.89%. Growth was allometric and the von Bertalanffy growth equation derived was Lt=43.5(1-e-0.8(t+0.0212)). The growth performance index (ɸ) was 3.18 and the longevity of the fish was estimated at 3.7 years. One-year-old plus fishes sustained the fishery (22 - 32 cm FL). Total mortality (Z), natural mortalty (M) and fishing mortality (F)were estimated at 3.70, 1.40 and 2.30, respectively, with an exploitation rate (E) of 0.62 and the exploitation ratio (U) of 0.60. Beverton and Holt yield per recruit (Y/R) and Biomass per recruit analysis indicated that the Emax was at 0.87, much higher than the present level of exploitation, reflecting the sustainable fishery along the coast. Standing stock biomass (SSB) was estimated at 7215.7 t, and the spawning stock biomass formed 55.5% of the SSB. Thompson and Bell analysis indicated the MSY as 8125 t, at F-factor, 2.6. The biological reference points FCURR/FMSY (0.4) and BCURR/BMSY (1.5) were at safe levels, signifying the scope for fishery enhancement