scholarly journals A comparison of food sources of nudibranch mollusks at different depths off the Kuril Islands using fatty acid trophic markers

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12336
Author(s):  
Anatolii Komisarenko ◽  
Vladimir Mordukhovich ◽  
Irina Ekimova ◽  
Andrey Imbs
Keyword(s):  
Fatty Acid ◽  
Trophic Ecology ◽  
Kuril Islands ◽  
Food Sources ◽  
Soft Corals ◽  
Sea Anemones ◽  
The Kuril Islands ◽  
High Level ◽  
Benthic Ecosystems ◽  
Trophic Markers

Gastropod molluscs such as nudibranchs are important members of deep-sea benthic ecosystems. However, data on the trophic ecology and feeding specialization of these animals are limited to date. The method of fatty acid trophic markers (FATM) was applied to determine the dietary preferences of nudibranchs off the Kuril Islands. Fatty acid (FA) compositions of Dendronotus sp., Tritonia tetraquetra, and Colga pacifica collected from deep waters were analyzed and compared with those of Aeolidia papillosa and Coryphella verrucosa from the offshore zone. The high level of FATM such as 22:5n-6 and C20 monounsaturated FAs indicated that Dendronotus sp. preys on sea anemones and/or anthoathecates hydroids similarly to that of shallow-water species A. papillosa and C. verrucosa. The high percentage of tetracosapolyenoic acids and the ratio 24:6n-3/24:5n-6 indicated that T. tetraquetra preys on soft corals such as Gersemia and/or Acanella at a depth of 250 m, but soft corals of the family Primnoidae may be the main item in the diet of T. tetraquetra at a depth of 500 m. The high content of Δ 7,13-22:2 and 22:6n-3 shows that C. pacifica can feed on bryozoans. In C. pacifica, 22:5n-6 may be synthesized intrinsically by the mollusks, whereas odd-chain and branched saturated FAs originate from associated bacteria.

scholarly journals PACIFIC COD OF THE KURIL ISLANDS: STOCK AND CONTEMPORARY FISHING

Fisheries ◽  
2020 ◽  
Vol 2020 (4) ◽  
pp. 44-51
Author(s):  
Aleksandr Zolotov ◽  
Nikolay Antonov ◽  
Olga Maznikova
Keyword(s):  
Kuril Islands ◽  
Pacific Cod ◽  
The North ◽  
Trawl Fishing ◽  
Northern Kuril Islands ◽  
The Kuril Islands ◽  
High Level ◽  
North And South ◽  
South Kuril Islands

The paper analyzes the long-term dynamics of stocks and annual catches of Pacific cod of the Kuril Islands, and also considers the structure of its modern fishery, taking into account the changes that have occurred in the organization of its coastal fishing in recent years. It was shown that the dynamics of commercial biomass of Pacific cod in the Northern and Southern Kuril Islands is comparable to that in 1975-2020 for groups in the southeastern part of the Bering Sea, the Karagin and Olyutor bays, on the shelf of Western Kamchatka, and in south-western Sakhalin. Development of the cod fishery in the North and South Kuril Islands in 1980-2019 went in accordance with the dynamics of stocks, the maximum catches were observed during the period of a high level of abundance of both groups in the 1980s. While the structure of the cod fishery on the shelf of the Northern Kuril Islands to date can be considered established, the development of fishing in the South Kuril Islands in the last two decades went by the gradual replacement of trawl fishing in the winter-spring period with snorkeling in the summer season.

scholarly journals Masquerade, mimicry and crypsis of the polymorphic sea anemone Phyllodiscus semoni and its aggregations in South Sulawesi

2011 ◽  
Vol 80 (4) ◽  
pp. 251-268 ◽  
Author(s):  
Bert W. Hoeksema ◽  
Andrea L. Crowther
Keyword(s):  
Sea Anemone ◽  
Soft Corals ◽  
Sea Anemones ◽  
Stony Corals ◽  
South Sulawesi ◽  
Toxicological Studies ◽  
The Subject ◽  
High Level ◽  
Intraspecific Morphological Variation ◽  
Spermonde Archipelago

Phyllodiscus semoni is a morphologically variable sea anemone species from the Indo-Pacific with morphotypes ranging from upright and branched to low-lying and rounded. The apparent camouflage strategies of this sea anemone allow it to resemble other species or objects in its environment, such as stony corals, soft corals, seaweeds, or rocky boulders covered by algae, which may help it to avoid recognition by potential predators. Occasionally, it occurs in aggregations that may result from asexual reproduction. A high level of intraspecific morphological variation, including co-occurring aggregations of three different morphotypes, was observed in the Spermonde Archipelago off Makassar, South Sulawesi, Indonesia. The co-occurrence of aggregations with different morphotypes suggests that Phyllodiscus is a highly polymorphic monospecific genus. Sea anemones of this genus are not frequently encountered at other localities and the number of morphotypes seems large. Therefore, it is unlikely that we are dealing with more than one species that are all concentrated in a single area. Phyllodiscus sea anemones are considered dangerous to humans because their nematocysts contain highly toxic venoms that may inflict harmful stings. Therefore they are the subject of recent toxicological studies. The present paper aims to assist in the recognition of these highly variable hazardous animals and to discuss the appearance of their aggregations.

scholarly journals Dietary preferences of brachyuran crabs from Taiwan for marine or terrestrial food sources: evidence based on fatty acid trophic markers

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Meike Stumpp ◽  
Reinhard Saborowski ◽  
Simon Jungblut ◽  
Hung-Chang Liu ◽  
Wilhelm Hagen
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Essential Fatty Acids ◽  
Food Sources ◽  
Terrestrial Species ◽  
Trophic Preferences ◽  
Land Crabs ◽  
Trophic Markers

Abstract Background Trophic interactions are key processes, which determine the ecological function and performance of organisms. Many decapod crustaceans feed on plant material as a source for essential nutrients, e.g. polyunsaturated fatty acids. Strictly herbivorous feeding appears only occasionally in marine decapods but is common in land crabs. To verify food preferences and to establish trophic markers, we studied the lipid and fatty acid composition of the midgut glands of two marine crab species (Grapsus albolineatus and Percnon affine), one semi-terrestrial species (Orisarma intermedium, formerly Sesarmops intermedius), and one terrestrial species (Geothelphusa albogilva) from Taiwan. Results All species showed a wide span of total lipid levels ranging from 4 to 42% of the dry mass (%DM) in the marine P. affine and from 3 to 25%DM in the terrestrial G. albogilva. Triacylglycerols (TAG) were the major storage lipid compound. The fatty acids 16:0, 18:1(n-9), and 20:4(n-6) prevailed in all species. Essential fatty acids such as 20:4(n-6) originated from the diet. Terrestrial species also showed relatively high amounts of 18:2(n-6), which is a trophic marker for vascular plants. The fatty acid compositions of the four species allow to clearly distinguish between marine and terrestrial herbivorous feeding due to significantly different amounts of 16:0, 18:1(n-9), and 18:2(n-6). Conclusions Based on the fatty acid composition, marine/terrestrial herbivory indices were defined and compared with regard to their resolution and differentiating capacity. These indices can help to reveal trophic preferences of unexplored species, particularly in habitats of border regions like mangrove intertidal flats and estuaries.

scholarly journals The evaluation of seasonal fatty acid composition and food sources of Pileurobrachia pileus (Ctenophora) in terms of trophic marker fatty acids in the Southeastern Black Sea

2021 ◽  
Vol 38 (2) ◽  
pp. 211-218
Author(s):  
Nurgül Şen Özdemir ◽  
Ali Muzaffer Feyzioğlu ◽  
Fatma Caf
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Black Sea ◽  
Lipid Content ◽  
Seasonal Changes ◽  
Food Sources ◽  
Epa And Dha ◽  
Trophic Markers

Seasonal changes of the lipid and fatty acid composition of Pleurobrachia pileus investigated monthly from March 2012 to February 2013. Average total lipid content was determined as percentage (%) and per individual (mg ind-1). It was highest in February (1.48 %; 3.55 mg ind-1). However, it was proportionally the lowest in April (0.40 %), and per individual in August (0.33 mg ind-1). Major fatty acids of P. pileus were identified as 16:0, 14:0, 11:1 n-9c, 20:5 n-3, and 22:6 n-3. P. pileus had on average 27.27 % ∑SFA, 25.04 % ∑MUFA and 47.63 % ∑PUFA content. EPA and DHA were the major fatty acids from PUFA. Seasonal changes of DHA were more obvious than EPA (p<0.05). Herbivore calanoid zooplankton trophic markers; 20:1 n-9 and DHA/EPA and herbivory trophic markers; EPA and DHA content were high in P. pileus fatty acids. It showed that herbivory fatty acids were taken by feeding from herbivory zooplankton and phytoplankton. Diet was an important factor in seasonal fatty acid changes of P. pileus. In addition, we revealed that P. pileus has a rich lipid content and fatty acid composition and plays an important role in the Southeastern Black Sea ecosystem functionalities between herbivory and carnivory species.

scholarly journals Geographic variation in fatty acid composition and food source of the commercial clam (Venerupis decussata, Linnaeus, 1758), from the Tunisian Coast: Trophic links

2019 ◽  
Vol 70 (1) ◽  
pp. 289 ◽  
Author(s):  
S. Bejaoui ◽  
D. Boussoufa ◽  
K. Telahigue ◽  
I. Chetoui ◽  
F. Ghribi ◽  
...  
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Trophic Ecology ◽  
Abiotic Factors ◽  
Principal Component ◽  
Food Sources ◽  
Dietary Analysis ◽  
Tunisian Coast ◽  
Trophic Links

Lake and coastal Tunisian areas are rich biodiversity habitats, although little information is available about the distribution of food sources for the inhabitant species. In this study, a fatty acid analysis was used to study the trophic ecology of Venerupis decussatac ommunities from 10 sites located along the Tunisian Coast. The richest population in fatty acids was found in S4 followed by S5 and S8, while that of S1, S3 and S10 were the least rich. Results from multivariate analysis confirmed the ecological position of the studied population based on their fatty acid composition. Our results divided the ten studied populations into three similar groups according to their ecological and geographical positions in relation to environmental parameters and food and trophic links. A principal component analysis revealed that diatoms and dinoflagellates were the predominate diets in all the sampling stations. Bacteria and urban discharge dominated the dietary source of clams from S10 and S9. Zooplankton were the preferred diet of V. decussata harvested from the two S2 and S3 lakes; although green algae, phytoplankton and detritus were absent from the dietary source of the two previous populations. Despite spatial differences, clams from the north and the south could be easily distinguished from each other, which indicates the utility of this method in the dietary analysis of different food chain links. This study proves that geographic, ecologic and abiotic factors as well as their mutual interaction should be properly investigated in studies focusing on the trophic chains of aquatic ecosystems.

scholarly journals The burial ground on Tankovoye Lake (Iturup Island): brief history and results of researches

2021 ◽  
pp. 58-81
Author(s):  
Oksana Yanshina ◽  
Keyword(s):  
Kuril Islands ◽  
Burial Ground ◽  
Scientific Publications ◽  
Radiocarbon Dates ◽  
General Terms ◽  
Archaeological Collections ◽  
The Kuril Islands ◽  
Key Sites ◽  
Burial Objects ◽  
High Level

The burial ground located on a bank of Tankovoye Lake (Kuibyshevskoye) is one of the key sites in the archaeology of the Kuril Islands. This is due not only to the fact that huge archaeological collections reflecting all stages of peopling of the region have been collected here over many years of excavations but also to the fact that this burial ground still remains the only object of this kind throughout the entire islands chain. Moreover, apart of the burials themselves, the stone burial structures, which have not yet been recorded on other sites of the Kuril Islands, but have analogies in the Jōmon culture, were also revealed at the site. Interest in this site is also enhanced by recent genetic studies, which unexpectedly demonstrated a high level of genetic similarity of a person buried here with modern Koryaks and Itelmens. At the same time, despite the site’s uniqueness, it is heavily underrepresented in available scientific publications. Information about it can be found only in the field reports and in few the hard-to-reach regional publications. Therefore, this article provides a brief overview of all data gathered at this site. It is based on the field reports, data from the private archive of Y. Knorozov, museum collections of the Sakhalin Regional Museum, and on the results of the author’s own research as well. Summing up the outcomes of long-term researches, we have to state that the site’s unique objects remain almost unexplored. For many years, studies here were limited to visual examination, cleaning up of the dune opening, and surface artifact gathering. Therefore, the nature of the burial objects found at the site might be recognized only in the most general terms. Their cultural affiliation also remains questionable. Radiocarbon dates suggest that the early Epi-Jōmon epoch is most powerfully represented near the lake, while the bulk of the ceramics collected here belongs to the later stage of this epoch (in accordance with archaeological data from Hokkaido). In addition, artifacts of Middle and Final Jōmon, Okhotsk culture, Satsumon-Tobinitai culture, and Ainu are presented here as well. Presumably, people could bury their dead here during the epochs of Final Jōmon, Epi-Jōmon and, possibly, the Okhotsk culture.

Fatty acid composition as an indicator of possible sources of nutrition for soft corals of the genusSinularia(Alcyoniidae)

2012 ◽  
Vol 92 (6) ◽  
pp. 1341-1347 ◽  
Author(s):  
Andrey B. Imbs ◽  
Nikolay A. Latyshev
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Host Tissue ◽  
Coral Host ◽  
Total Lipids ◽  
Soft Corals ◽  
Fa Markers ◽  
High Level ◽  
Negligible Contribution

Fatty acids (FAs) composition of eight zooxanthellate soft corals,Sinularia leptoclados, S. flexibilis, S.aff.deformis, S. lochmodes, S. cf.muralis, S. densa, S. notandaandS. cruciatacollected in Van Phong Bay (Vietnam) were studied to identify possible origin of unsaturated FAs. The main FAs were 14:0, 16:0, 7-Me-16:1n-10, 16:1n-7, 16:2n-7, 18:0, 18:1n-9, 18:4n-3, 20:4n-6, 20:5n-3, 22:6n-3, 24:5n-6 and 24:6n-3. On the average, saturated, monounsaturated, and polyunsaturated FAs (PUFAs) contributed 35.6, 6.2 and 54.0% of total coral FAs, respectively. PUFAs of n-6 series predominated in all animals (n-6/n-3 > 1.6). The content of 20:4n-6 varied from 10.2 to 23.8%. The main n-3 PUFA was 18:4n-3 (on the average, 5.4%); the contribution of 20:5n-3 and 22:6n-3, typical PUFAs of marine organisms, was not more than 2.4 and 3.9%, respectively. InSinularia, PUFAs were produced by endosymbiotic dinoflagellates (zooxanthellae) and the coral host tissue, or obtained with food. Zooxanthellae can be considered as the source of C16PUFAs and 18:4n-3. The coral host synthesized 18:2n-7, 24:5n-6 and 24:6n-3 acids. The low content of 18:1n-7, saturated odd-chain FAs and saturated methyl-branched FAs indicated a negligible contribution of bacteria to total lipids ofSinularia. A comparison of the levels of diatom and dinoflagellate FA markers in coral and plankton lipids showed eukaryotic microalgae to play a secondary role in feeding ofSinularia. The high level of 20:4n-6 may be considered as an indicator of heterotrophic feeding ofSinularia.

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