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Vasanth, K.; Muthupandi, K.; Naganandhini, V.; Radhakrishnan, K., and Narayanan, M., 2025. Length-weight relationships of eight pelagic fish species caught by drift longlines in the Gulf of Mannar, India. Journal of Coastal Research, 41(3), 510–515. Charlotte (North Carolina), ISSN 0749-0208. The length-weight relationships were estimated for eight pelagic species caught in the Gulf of Mannar, India, using experimental longlines. The experimental study was conducted from January to October 2022 in fortnightly intervals using longlines (3000 m for needlefish and 11,250 m for carangids), each equipped with 600 “J”-type fishing hooks of various types (straight, reversed, kirbed). The hook numbers used were standard sizes that ranged from 8 to 11 for both groups (needlefish and carangids). The longlines were fabricated with polyamide monofilament and operated from 1 to 2 m depth for needlefish and 20 to 25 m depth for carangids for 3 to 5 hours for both longline units. Overall, 21,150 hooks were deployed in 24 fishing trials for each experimental longline. A maximum total length was recorded for four needlefish species, Strongylura strongylura (80), Tylosurus choram (91), Tylosurus crocodilus (97), and Ablennes hians (96), and four carangids species, Caranx bajad (60.5), Alectis indicus (62), Caranx ignoblis (69), and Scomberomorus commerson (74). In terms of growth, the length-weight relationships revealed positive allometric growth (b >3) for three species of carangids, C. bajad, S. commerson, and A. indicus (p < 0.05) and negative allometric growth (b <3) for four species of needlefishes, T. choram, S. strongylura, T. crocodilus, and A. hians, and one species of carangid, C. ignoblis.

Soybean is often damaged by hypoxia caused by waterlogging at the seedling stage. Hypoxia severely inhibits root development and retards plant growth. We aimed to clarify phenotypic variation in root development under hypoxia condition at the seedling stage using diverse soybean accessions. Root development in 162 accessions was evaluated in hydroponic culture. Substantial changes under hypoxia were investigated by means of WinRHIZO analysis before and after the treatment. We found significant phenotypic variation in hypoxia tolerance in root among the 162 accessions. A principal components analysis indicated an association between hypoxia tolerance and the country of origin. We found three new accessions which have a high ability to develop roots under hypoxia (Kokubu 7, Maetsue zairai 90B, and Yahagi). Root development in selected accessions was also evaluated in soil culture. Root development levels in hydroponic and soil culture were significantly correlated. These results will provide important information on waterlogging damage in regions where waterlogging occurs. The three accessions with hypoxia-tolerant roots might be useful for genetic improvement of waterlogging tolerance of modern soybean varieties.

Water flea ( Daphnia magna ) is an important live prey species for feeding larvae and juvenile fish and is also used as a feed ingredient in aquaculture. The growth performance and nutritional content of D. magna can be enhanced by diets. In this study, one freshwater microalgae Euglena gracilis (EG), one marine microalgae Pavlova lutheri (PL), and four commercial dried microalgal‐based diets (Algome [dried Schizochytrium sp.], Naturiga [dried Spirulina platensis ], ProteinPlus [PP] and AlgomeGrow [dried Chlorella sp.]) were evaluated for Daphnia production. Higher survival (68%) was supported by the PP diet, and total length was improved by using fresh microalgae EG. Algome (8.91%) and PP (8.77%) diets had resulted in higher crude lipid content, whereas the highest crude protein was obtained by the Naturiga diet (55.66%) in D. magna . D.magna fed Algome diet showed the highest docosahexaenoic acid (DHA; C22:6n‐3) accumulation, whereas eicosapentaenoic acid (EPA; C20:5n‐3) level was enhanced by PP and arachidonic acid (ARA) level was only supported by Naturiga diet. A strong correlation was observed between certain fatty acid groups (Oleic acid, Ʃ n‐3, and Ʃ n‐3 highly unsaturated fatty acids [HUFAs]) in the D. magna body and diets. In terms of essential amino acid contents of D. magna , the AlgomeGrow diet had the best performance at the end of the experiment.

Root foraging and root physiology such as exudation of carboxylates into the rhizosphere are important strategies for plant phosphorus (P) acquisition. We used 100 chickpea (Cicer arietinum) genotypes with diverse genetic backgrounds to study the relative roles of root morphology and physiology in P acquisition. Plants were grown in pots in a low-P sterilized river sand supplied with 10 μg P g−1 soil as FePO4, a poorly soluble form of P. There was a large genotypic variation in root morphology (total root length, root surface area, mean root diameter, specific root length and root hair length), and root physiology (rhizosheath pH, carboxylates and acid phosphatase activity). Shoot P content was correlated with total root length, root surface area and total carboxylates per plant, particularly malonate. A positive correlation was found between mature leaf manganese (Mn) concentration and carboxylate amount in rhizosheath relative to root DW. This is the first study to demonstrate that the mature leaf Mn concentration can be used as an easily measurable proxy for the assessment of belowground carboxylate-releasing processes in a range of chickpea genotypes grown under low-P, and therefore offers an important breeding trait, with potential application in other crops.

Small-spotted catshark Scyliorhinus canicula (Linnaeus, 1758) is confronted since 2000 to a drastic decline of captures in Tunisian northern areas where it formerly was quantitatively and qualitatively very abundant. A study conducted in the area showed that males and females sexually matured between 400–478 mm and 364–471 mm total length (TL), respectively. The largest male and female were 521 mm and 531 mm TL, respectively and weighed 449 and 445.5 g, respectively. There was a not significant relationship total mass vs. TL between males and females. Conversely, the relationship of liver mass vs. TL significantly differed between sexes. Both HSI and GSI values did not present significant differences between males and females. There was a not significant relationship total mass vs. TL between males and females. Both male and female HSI reached high values in adults, significantly higher than those of sub-adults. Both male and female GSI values increased with TL of specimens; additionally, they showed significant differences between juveniles and sub-adults and also between sub-adults and adults. The OSI values were significantly different between juvenile and sub-adult females, and also between sub-adult and adult females. Monthly mean values of adult male and female HSI did not significantly vary throughout the year. Significant monthly changes were recorded in mean values of adult male however no significant changes were observed in monthly mean of GSI and OSI for adult females. Vitellogenic activity and production of egg cases permanently occurred throughout the year. The diameter of largest yolky oocytes ranged from 20.1 to 23.0 (mean = 21.43 ± 1.07) and weighed from 0.64 to 0.90 g (mean = 0.78 ± 0.09). Some measurements were taken on egg cases: length with horns ranged 42.5-55.7 mm with mean = 48.9 ± 2.9, width ranged 13.6–19.7 mm with mean = 16.50 ± 0.9, while the total mass of complete egg case ranged between 1.8 and 4.6 g, with mean = 2.4 ± 0.4. An annual fecundity estimation based on production of egg cases and oocytes during one year counted in adult females, enabled us to consider it between 40 and 240.

There has been no comprehensive study of body size in notothenioid fishes. Therefore I evaluated maximum total length (TL) as an axis of the evolutionary radiation. Lengths are provided for 141 species that collectively range in maximum adult size from 5.7 cm (Harpagifer nybelini) to 225 cm (Dissostichus eleginoides), a 39-fold difference. For the 138 species analyzed, the mean length is 33.5 cm and the median is 26.6 cm. Based on 10 cm-bins, notothenioids are apportioned into small (< 10 cm), medium (10–39 cm), medium-large (40–91 cm), and large (> 200 cm) size categories. The 20–29 cm bin contains the most species (32%). Most species (71%) are of medium size, 21% of species are medium-large, and 7% and ≈ 1% are small and large, respectively. The median lengths vary among the five cryonotothenioid families as well as among eight clades (genera and families). Among families, median and mean lengths are smallest in the Harpagiferidae and largest in Channichthyidae. Among clades, Harpagifer has the smallest median length (8.3 cm) followed by Artedidraco (12.5 cm). Several middle-sized clades do not differ in median size: Patagonotothen, Trematomus, Pogonophryne, and Bathydraconidae. Two clades of medium-large size species, Notothenia and Channichthyidae, are of similar size. A significant but weak positive relationship exists between maximum length and maximum depth. With the exception of miniature species ( ≤ 1 cm), the 126 species of cryonotothenioids (the Antarctic clade) encompass the range in size categories in actinopterygians in general, and the disparity in maximum lengths among individual species indicates that body size is an axis of the radiation. I discuss the size of notothenioids relative to other teleosts, the ecological implications of large species in the food web, and the similarity of the cryonotothenioid axes of diversification to those of Lake Baikal sculpins.

In this study, we present the relationships between total length, unburied length, and shell width and between total length and net weight for the critically endangered Pinna nobilis. This is the first transplantation study in which live specimens of P. nobilis have been used for estimating the length–weight relationship by deploying the unburied length. Length–length relationships were all linear for all cases (r2 > 0.900), whereas the length–weight relationship was negative allometric with the values of the exponent b ranging from 2.159 to 2.828. These relationships are important because they offer a restorative monitoring tool without damaging or sacrificing this endangered species, as total length can be computed using unburied length. By examining the relationships between different size dimensions in this re-allocated population, the present study also provided valuable insights for comparative growth studies, stock assessment models, and conservation purposes.

In 2020, the presence of a novel non-indigenous species, eastern tubenose goby Proterorhinus semipellucidus (Kessler, 1877), was documented in the Gulf of Finland, Baltic Sea. As tubenose goby invasion may have a comprehensive ecological impact on the local ecosystem, it has to be confirmed whether the species has established an independently reproducing population or persists through continuous invasions in this area. We examined the otolith microstructure to determine the age of specimens sampled from the southern and northern coasts of the Gulf of Finland. Additionally, otolith microchemistry analysis was carried out on the southern coast specimens. Otolith microstructure revealed the population’s age structure, showing the presence of different age classes, including younger individuals. The microchemistry analyses suggested that the specimens had hatched in brackish water salinities similar to those found in the sampling areas. This indicates local reproduction instead of introduction from the virtually freshwater Neva Bay, which is most likely the donor area of the studied populations. These data confirm the establishment of a self-sustaining reproducing population of eastern tubenose goby in the Gulf of Finland, eastern part of the brackish Baltic Sea.

This paper reports about the observations made with regard to 21 teleost species comprising 1657 specimens from the northern Tunisian coast. These specimens were found in an area with sufficient prey species to allow them to live and develop, as confirmed by the size to total body weight relationship. The high values of vacuity index are probably due to both sampling and fishing methods. Crustaceans and teleosts are the prey most frequently consumed by these species. Additionally, the high trophic levels (TROPH) (± 3.00) indicated that these teleost species belong among carnivores. Of all the species examined, only one, Sarpa salpa with TROPH = 2.00, was found to be herbivorous.

A freshly dead individual of the giant squid Architeuthis dux, presumably mutilated by a predator of bigger or comparable size, is reported from the south-western Indian Ocean in proximity to Reunion Island. The species was identified from body and beak morphology and validated genetically. The dorsal mantle length (DML) estimated from beak measurements (lower rostral length, LRL) varied between 2153 and 3060 mm depending on the allometric equation used. The Architeuthis dux individual described here is the biggest giant squid ever reported for the region.