Indian tuna fishery - production trend during yesteryears and scope for the future

Fishery for tuna and tuna like fishes in the country has been in vogue from time immemorial and presently involves fishery by coastal based fleets of varying specifications with different craft-gear combinations and longline fishery by large oceanic fishing vessels. The former undertakes short duration fishing trips and exploit mainly surface tunas in the outer shelf and adjacent oceanic waters. The tuna landings though nominal during 1950-2005, registered a continuous increase over the years from a minimum of 848 t (1951) to 46,334 t (2000). With the introduction of targeted fishing for oceanic tunas during 2005-‘06, the landings improved and reached the maximum of 129,801 t in 2008. The fishery was supported by nine species, five coastal/neritic species and four oceanic species. Coastal tunas formed 57% of the tuna catch during 2006-’10 and was represented by the little tuna (Euthynnus affinis), frigate tuna (Auxis thazard), bullet tuna (Auxis rochei), longtail tuna (Thunnus tonggol) and bonito (Sarda orientalis). The oceanic species, which formed 43% of tuna catch, were yellowfin tuna (Thunnus albacares), skipjack tuna (Katsuwonus pelamis), dogtooth tuna (Gymnosarda unicolor) and bigeye tuna (Thunnus obesus). Information collected from different sources suggested that longliners operating in Indian EEZ and adjacent international waters caught around 87,000 t of tuna annually during 2006-'10. Catch was supported by three species dominated by yellowfin tuna and small proportion of big-eye and dogtooth tuna. Since fishery by coastal based units restricted to small areas and share of the catch by longliners from EEZ are not clearly known, systematic assessment of tuna stock in Indian EEZ is very difficult. However, the evaluation of the fishery scenario indicated only limited scope for improving tuna production from certain areas of coastal waters; whereas enormous scope remain for increasing tuna production from the oceanic waters of EEZ. However, since tunas being straddling resources shared by several nations, exploitation at one area will influence the fishery in other areas

Fishery of yellowfin tuna Thunnus albacares (Bonnaterre, 1788) in the Indian EEZ with special reference to their biology and population characteristics

The fishery and population characteristics of yellowfin tuna, Thunnus albacares were monitored during 2006-'10. They were being caught as bycatch along the coasts of Indian mainland and island territories by several coast-based fishery for a long time. Their landings by coast-based fishery was very nominal (4,171 t year-1 average for 1985-2000) with considerable annual fluctuations until targeted fishery for the species developed during the last decade. This resulted in considerable improvement in landings to a peak of 37,963 t in 2007. The production declined thereafter due to shift in the target resource of these vessels from yellowfin tuna to billfishes and elasmobranchs. The annual average catch in oceanic fishery during 2006-'10 was 85,928 t. The coast-based fishery exploit mainly surface tunas in the outer shelf, adjacent oceanic areas and seamounts. At national level, the pooled catch was supported by 22 - 202 cm fishes with 66.3 cm as annual mean. Relatively large fishes of 40 to 202 cm with 83.4 cm as mean length and dominated by 58-102 cm groups supported the catch in line fishery. The gillnet fishery comprised 22 to 123 cm fishes dominated by 44-82 cm size and other gears landed 26 to 110 cm size fishes dominated by 42 to 80 cm size. Length at capture was 44.8 cm in gillnets, 60.3 cm in hooks and lines and 42.7 cm in other gears. The length at first maturity was 57.6 cm and optimum length for exploitation was 61.1 cm. They spawn round the year with peak during August-January. The mean relative fecundity was 4,36,330 ova per kg body weight and it varied with size of the fish. Study shows that stock of yellowfin tuna in Indian waters remain very healthy with large proportion of spawning stock biomass. Exploitation range of coastal based fishery being very limited and oceanic fishery concentrated mainly in international waters, large area of Indian EEZ remain unexploited by the country. Overall assessment of fishery scenario indicates possibility of large proportion of yellowfin tunas, especially larger ones remain inaccessible to Indian fishers and hence considerable scope for expanding the fishery

Taxonomy and key for the identification of tuna species exploited from the Indian EEZ

Tuna samples were collected from the commercial landings at Kochi, Tuticorin, Mangalore, Visakhapatnam, Veraval and Lakshadweep at regular intervals during 2006-2010. Detailed morphometric data, viz., height of dorsal and anal fins, eye diameter, snout length, head height and height of body were collected. Otoliths were collected from eight species and analysed. Results indicated that structure and shape of the otoliths show species specific differences. Taxonomic details of tunas and tuna like species have been generated from the present as well as past studies and the species were redescribed with color photographs and keys for identification. The species included Thunnus albacares (Bonnaterre, 1788), Thunnus obesus (Lowe, 1839), Thunnus tonggol (Bleeker, 1851), Sarda orientalis (Temminck & Schlegel, 1844), Katsuwonus pelamis (Linnaeus, 1758), Euthynnus affinis (Cantor, 1849), Auxis thazard (Lacepède, 1800), Auxis rochei (Risso, 1810) and Gymnosarda unicolor (Rüppell 1836)

Capture based aquaculture of mud spiny lobster, Panulirus polyphagus (Herbst, 1793) in open sea floating net cages off Veraval, north-west coast of India

Capture based aquaculture (CBA) of the mud spiny lobster, Panulirus polyphagus was conducted in two cylindrical floating net cages of 6 m diameter and 4.5 m depth, made of HDPE sapphire netting of 18 mm mesh size. The cages were installed at a depth of 8 m, about 900 m away from the shore off Prabhas Patan, Veraval, India. Live lobsters were collected from lobster fishing centres of Veraval and Mahua regions of Gujarat and segregated into two groups: animals weighing 80-120 g (Group-1) and animals weighing < 80 g (Group-2). One thousand numbers of sub-adults of Group-1 with initial body weight of 99.75 ± 8.4 g, were stocked in Cage-1 and 1500 juveniles of Group-2 with initial body weight of 46.44 ± 8.8 g were stocked in Cage-2. The lobsters were fed twice daily with trash fish @ 8 % of the body weight by tray feeding. After the culture period of 90 days, no significant difference (p > 0.05) was observed in the survival rate (overall survival = 93.7 %) whereas, juvenile lobsters in Cage-2 showed weight increase of 1.49 g d-1 and specific growth rates of 1.51 % d-1 which was significantly higher (p < 0.05) than the weight increase of 1.17 g d-1 and specific growth rates of 0.80 % d-1 recorded from Cage-1. Results suggest that P. polyphagus has potential for capture based aquaculture in sea cage culture systems along Gujarat coast

Morphological divergence in Indian oil sardine, Sardinella longiceps Valenciennes, 1847– Does it imply adaptive variation?

The Indian oil sardine, Sardinella longiceps, is an important pelagic species in Indian waters, and shows divergent morphology while in sympatry. The reasons behind this divergent morphology were investigated using morphometric, genetic and nutritional analyses. Twenty-one morphometric characters (as percentage of standard length) and eight meristic characters were studied in the three variants to assess whether they are significantly diverged. Distinct clustering of morphotypes was evident in the principal component analysis on log-transformed ratios of morphological characters with PC1 and PC2, explaining 50.7% and 17.6% of the total morphological variation, respectively. PC1 was highly correlated with the distance from snout to anal origin, depth at dorsal, distance from snout to pelvic and distance from snout to first dorsal. PC2 was highly correlated with head length, caudal width and anal depth. Analysis of similarities (ANOSIM) was conducted using log-transformed morphometric ratios, with the results showing the clusters to be well differentiated (R = 0.511; P < 0.01). Similarity of percentage analysis (SIMPER) analysis showed that the differences in depth at the dorsal, anal base length, caudal width, distance from pelvic to anal origin, anal depth and eye diameter accounted for 52% of variations between variant 1 and 2. Differences in caudal width, distance from pelvic to anal origin, anal base length, depth at dorsal and anal depth accounted for 56% of the variation between variant 2 and 3. Differences in caudal width, eye diameter, anal base length, anal depth, distance from pelvic to anal origin accounted for 50% of the variation between variant 1 and 3. Genetic divergence was not significantly based on mitochondrial cytochrome c oxidase I (COI) or control region sequences. Proximate composition analyses showed significantly high fat content in variants 1&3 and significantly high protein content in variant 2, probably due to dissimilar dietary preferences. The study shows that morphotypes of the Indian oil sardine may be the result of divergent selection and adaptive variations, which need further investigation using a long-term sampling design

Post-frontline demonstration impact analysis of open sea cage culture among Sidi tribes in Gujarat

Front line demonstrations (FLD) evolved by the Indian Council of Agricultural Research are conducted under the close supervision of scientists of the National Agriculture Research System, where in technologies are demonstrated for the first time by the scientists themselves before being fed in to the main extension system of the state machinery. Post-front line demonstration impact analysis on open sea cage culture of finfishes and lobsters, among Sidi tribes of Gujarat aimed at assessing the socio-personal, socio-psychological and socio-economic and behavioural characteristics of Sidis - a primitive tribal group who are the beneficiaries of the open sea cage culture programme of the Central Marine Fisheries Research Institute (CMFRI) under the Tribal Sub-Plan (TSP) of the Government of India. Using multistage random sampling method, a sample of 135 Sidi tribals were selected from Veraval and Talala taluks in Junagadh District of Gujarat. The group consisted of 45 Sidis practising cage culture, 45 non-practising beneficiaries of the tribal society and 45 Sidis who were non-practising non-beneficiaries of the society. The findings of the study revealed that most of the participant beneficiaries (58.33%) were having high school level of education, compared to non-participant beneficiaries, most of whom were illiterates (55.55%). It could be inferred that, the participant beneficiaries had a higher average monthly income of ` 1,216.25 when compared to non-participant beneficiaries who earned an average monthly income of ` 854.25. Among the participant beneficiaries, 41.67% had medium level of knowledge in cage culture, 50% had medium level of attitude and 75% had medium level of perceived skill in cage culture technologies

Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure fl ux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defi ned as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (inmost higher eukaryotes and some protists such as Dictyostelium ) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the fi eld understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation it is imperative to delete or knock down more than one autophagy-related gene. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways so not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

Abstract: We present our current best estimate of the plausible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next several years, with the intention of providing information to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals for the third (O3), fourth (O4) and fifth observing (O5) runs, including the planned upgrades of the Advanced LIGO and Advanced Virgo detectors. We study the capability of the network to determine the sky location of the source for gravitational-wave signals from the inspiral of binary systems of compact objects, that is binary neutron star, neutron star–black hole, and binary black hole systems. The ability to localize the sources is given as a sky-area probability, luminosity distance, and comoving volume. The median sky localization area (90% credible region) is expected to be a few hundreds of square degrees for all types of binary systems during O3 with the Advanced LIGO and Virgo (HLV) network. The median sky localization area will improve to a few tens of square degrees during O4 with the Advanced LIGO, Virgo, and KAGRA (HLVK) network. During O3, the median localization volume (90% credible region) is expected to be on the order of 105, 106, 107Mpc3 for binary neutron star, neutron star–black hole, and binary black hole systems, respectively. The localization volume in O4 is expected to be about a factor two smaller than in O3. We predict a detection count of 1-1+12(10-10+52) for binary neutron star mergers, of 0-0+19(1-1+91) for neutron star–black hole mergers, and 17-11+22(79-44+89) for binary black hole mergers in a one-calendar-year observing run of the HLV network during O3 (HLVK network during O4). We evaluate sensitivity and localization expectations for unmodeled signal searches, including the search for intermediate mass black hole binary mergers