Deep-sea Shrimp Research Articles

First record of deep-sea caridean shrimp Acanthephyra fimbriata Alcock Anderson, 1894 (Crustacea: Decapoda: Acanthephyridae) from southwest coast of India.

The present work reports the new occurrence of deep-sea shrimp Acanthephyra fimbriata Alcock Anderson, 1894 from southwestern Indian waters. The samples were caught in bottom trawls conducted between the depths of 200 and 350 m from two fish landing centers off Kerala along Arabian Sea from the southwest coast of India during 2015. Additionally, a phylogenetic analysis was used to explore the relationships of the genus Acanthephyra based on two genes: mitochondrial cytochrome c oxidase subunit 1 (COI) and 16S DNA (16S) with the present specimen and sequences retrieved from NCBI GenBank. The results revealed intraspecies (COI: 0-3 % 16S: 0-0.3 %) and interspecies divergence (COI: 17.5-20.9 % 16S: 5.2-9.5 %) among A. fimbriata.

Population variations of Opal fish, Bembrops caudimacula Steindachner, 1876 from Arabian Sea and Andaman Sea: Evidence from otolith morphometry

Bembrops caudimacula dominates the deep-sea trawl catch in the exploratory surveys and as bycatch in the commercial trawling targeting deep-sea shrimps, in the Indian Exclusive Economic Zone. The intra-species variability in the bathy-demersal fish Bembrops caudimacula collected from two different ecosystems in the Indian Ocean were studied using otolith morphometric analysis. Five otolith size parameters (ferret length, ferret width, area, perimeter and weight), and five shape indices (roundness, rectangularity, ellipticity, form factor and circularity) were taken from forty-seven otoliths collected from two regions. Principal component analysis (PCA) and non-parametric PERMANOVA successfully differentiate the fishes from two regions based on the otolith morphometry. PCA indicated that ellipticity and otolith weight were the major factor responsible for the variation. The study indicated that otoliths of the fishes collected from Andaman Sea (part of Bay of Bengal) were more elliptic and massy compared to those collected from the Arabian Sea. This is the first work on the differentiation of B. caudimacula population from these two unique ecosystems, using otolith morphometry which is highly imperative to understand its population structure. Our study confirmed the suitability of otolith morphometric studies as an easiest and inexpensive method for differentiating the fish populations.

Bathyal and abyssal demersal bait-attending fauna of the Eastern Mediterranean Sea

Baited cameras were deployed over a depth range of 532–5111 m in the Ionian Sea to characterise the large mobile fauna. The planned installation of a neutrino telescope also offers the potential for biological observatories. The current study was intended to aid observatory placement. At increasing depths, sediment was observed to become more uniform and animal burrows and tracks reduced. A total of 10 species of deep-sea fishes were identified from images; four elasmobranchs, which were not recorded deeper than 1841 m, and six teleosts. At depths > 3000 m, including Calypso Deep, the deepest point in the Mediterranean, only one fish species was observed; the Mediterranean grenadier, Coryphaenoides mediterraneus (3400–5111 m), extending this species’ maximum recorded depth to 5111 m. Four species of decapod crustacea could be identified from images. The dressed deep-sea shrimp, Acanthephyra eximia (1346–5111 m) was the only invertebrate recorded at abyssal depths, including the deepest point. A faunal change was detected at ~ 1000 m depth. Incorporating other studies from the Eastern Mediterranean identified additional faunal boundaries at ~ 1500 m and ~ 2500 m. The time from landing the observation equipment to the arrival of the first fish increased exponentially with depth at a slower rate to that observed in the Atlantic Ocean. The estimated density of bait-attending deep-sea fish was, therefore, significantly impoverished compared to the Atlantic Ocean at equivalent depth. Barriers to colonisation, low resource input, and high temperature at depth relative to the Atlantic Ocean are probable causes of the impoverished fauna.

New records of six deep-sea caridean shrimps (Crustacea: Decapoda) fromthe Ryukyu Islands and its adjacent waters, southwestern Japan.

Six species of caridean shrimps from four families are recorded from Japanese waters for the first time on the basis of material from the Ryukyu Islands and its adjacent waters, collected during research cruises of the T/RV "Toyoshio-maru" of Faculty of Applied Biological Science, Hiroshima University: two species of Crangonidae, Lissosabinea unispinosa Komai, 2006 and Pseudopontophilus serratus Komai, 2004; one species of Oplophoridae, Systellaspis pellucida (Filhol, 1885); one species of Pandalidae, Calipandalus elachys Komai Chan, 2003; and two species of Pasiphaeidae, Pasiphaea debitusae Hayashi, 1999 and P. gracilis Hayashi, 1999. Of them, L. unispinosa, Pseudopontophilus serratus, Pasiphaea debitusae and P. gracilis are heretofore known from the South-West Pacific localities, and then the geographical ranges of these four species are greatly extended to the north and west. Illustrations and/or colour images are provided for each species to supplement previous descriptions and to give evidence for identification.

Two new records of deep sea shrimp under the genus Parapontocaris (Crustacea: Decapoda: Crangonidae) from the southwestern coast of India.

This paper reports the occurrence of two species of the crangonid genus Parapontocaris Alcock, 1901 in waters off Kerala from the southwestern coast of India, viz. P. levigata (Chace 1984) and P. bengalensis (Wood-Mason Alcock 1891). Although P. bengalensis was reported off Bay of Bengal in India, after 121 years this species was now recorded off Kerala, Arabian Sea. Specimens were obtained at a depth of 250-300 m from Kalamuku (9°59'02.91"N /76°14'33.14"E) and Sakthikulangara (8°56'60.78"N /76°32'34.27"E) fish landing centres. Interspecies genetic divergence (COI: 8.8-9.1% 16S DNA: 2.1-6.2 %) was recorded in the present specimen P. bengalensis and NCBI sequences.

Length-weight relationships of eight deep-sea fish species collected from the southwest coast of India

Length-weight relationships (LWR) for eight deep-sea fishes belonging to six families collected from the south west coast of India are presented. Specimens were caught by deep-sea shrimp trawls with mesh size 24 mm during 2011 and 2013. The b values ranged from 2.13 to 3.71 and the coefficient of determination (r2) ranged from 0.84 to 0.98. A new standard length maximum was recorded for Neoscopelus microchir. The b values estimated during the present study were compared with the values estimated using models based on Bayesian approach deposited in Fish Base.

Patterns of trophic resource use among deep-sea shrimps in the Northern Benguela current ecosystem, Namibia

The marine waters of Northern Benguela Ecosystem (NBE) off the Namibia support high abundances of different marine species. Seven shrimp species: Aristeus varidens, Funchalia woodwardi, Glyphus marsupialis, Heterocarpus grimaldi, Solenocera africana, Plesionika martia and Parapeneus longirostris, form an important trophic linkage between primary consumers and other trophic levels in the NBE. This study examined their trophic resource use patterns using their stable isotope measurements (δ15N, δ13C). Results indicated that although their trophic niche overlapped, there were some variations in their carbon sources (δ13C) and feeding positions (δ15N). Heterocarpus grimaldi fed at a higher trophic position, while P. longirostris fed at the lowest position. Latitude, body size and depth contributed to the variations observed in isotopic values of these crustaceans. This study represents the first attempt at understating trophic resource use patterns of crustaceans in the NBE using stable isotopic measurements. Further research is needed to investigate if the trophic interactions observed in this study are consistent across time and space.

Stock structure analysis of the Arabian red shrimp (Aristeus alcockiRamadan, 1938) in the Indian coast with truss network morphometrics

The Arabian red shrimp (Aristeus alcocki Ramadan, 1938) is a deep-sea penaeoid shrimp that forms a major commercial fishery in the Indian coast. However, the spawning population of this species along the Indian coast is poorly known. To study this, stock structure of A. alcocki using truss morphometry was employed. A total of 1842 matured specimens were collected from five geographical locations (Tuticorin (SET), Chennai (SEC), Nagapattianam (SEN), Sakthikulangara (SWS), and Kalamuku (SWK)) along the Indian coast. Thirty-nine truss distances were extracted from each specimen and analyzed by multivariate methods (i.e., principal component analysis (PCA), discriminant functions (DF), and hierarchical cluster analysis). The results of the PCA indicated that the first two components cumulatively explained >70% (female: 72.1%; male: 71.5%) of the total morphometric variation. Stepwise DF analysis indicated that abdominal variables significantly discriminated the populations at different locations. The results clustered the five samples into a minimum of two groups: samples from SWK clustered in group I, whereas rest of the samples clustered in group II. Morphometric variation between the groups was significant for each sex. Significant differences between the groups may be attributed to geographical and environmental conditions, suggesting separate management strategies for resource sustainability.

Reproduction in the deep-sea penaeoid shrimp Aristeus alcocki Ramadan, 1938 (Decapoda: Penaeoidea: Aristeidae) from southwestern India

The Arabian red shrimp, Aristeus alcocki Ramadan, 1938, is one of the targets of commercial trawlers operating since 2000 along the Indian coasts at depths of 200–850 m. We report for the first time on the reproductive biology, insemination frequency, ovarian maturation, gonadosomatic index (GSI), size at maturity, and fecundity of A. alcocki investigated macroscopically and validated histologically using monthly trawl samples from the southwestern coast of India. Females have an open thelycum with five gonad developmental stages (I to V) and two stages (I and II) in males. A total of 4,170 specimens were examined and 68.6% of the females had been inseminated (carapace length (CL) 22.0–53.0 mm), predominantly during January to May. Females in stage I (immature) measured on average CL 25.5 ± 0.87 mm, those in stages IV and V (mature) CL 41.5 ± 0.62 mm. Immature males were smaller, mean CL 20.5 ± 0.5 mm. Size at first sexual maturity for females was estimated as CL 35.07 mm (total length (TL) 120–170 mm) and the inseminated specimens (CL50is) were mature at CL 31.45 mm using a non-linear method. The smallest mature female was CL 35 mm, whereas the size at maturity (CL50ms) of males was estimated as CL 19.6 mm (TL 75–96 mm). We also report synchronous oocyte development and continuous spawning activity with a peak during January to April. Information on the reproduction of this deep-water shrimp will help fishery managers estimate the stock sustainability and develop resource management measures.

Effects of environmental and anthropogenic drivers on the spatial distribution of deep-sea shrimps in the Ligurian and Tyrrhenian Seas (NW Mediterranean)

In the Mediterranean Sea, Aristaeomorpha foliacea and Aristeus antennatus are the most important target species of deep-sea trawl fisheries. Previous studies performed in several areas of the Mediterranean highlighted the key role played by both environmental factors, such as temperature, and anthropogenic activities, such as fishing, in affecting the abundance and distribution of the two species. The present study is aimed at investigating the effects of environmental and anthropogenic drivers on the abundance and spatial distribution of A. foliacea and A. antennatus in the Ligurian and northern and central Tyrrhenian Seas (NW Mediterranean). To this end, the time series of MEDITS trawl survey data (1994–2015) were analyzed together with environmental variables, namely sea surface temperature, current speed, and fishing effort by means of GAM. The results show that fishing plays an important role in shaping the spatial distribution of the two species. A. antennatus is prevalent where fishing effort is higher; this can be related to the higher resilience of blue and red shrimp to fishery impact. In contrast, high temperatures are associated to the prevalence of A. foliacea. Therefore, the abundance and spatial distribution of this species is mainly driven by temperature.

First Report of the Ectoparasitic Isopod, Holophryxus acanthephyrae Stephensen 1912 (Cymothoida: Dajidae) in the South Atlantic: Recovered from a New Host, the Deep-Sea Shrimp, Acanthephyra acanthitelsonis Spence Bate, 1888

The crustacean family of isopods, Dajidae, comprises 18 genera containing 54 species with widespread distribution. The species of this family are ectoparasites, especially on euphausiids, mysids and shrimps. The species of Holophryxus acanthephyrae has a life cycle involving a first intermediate host (copepod) and a definitive host (shrimp), and adheres particularly on deep-sea shrimps of genus Acanthephyra. Here, we make the first report of dajid isopod Holophryxus acanthephyrae from Brazilian waters (South Atlantic) and the first occurrence as parasite on deep-sea shrimp Acanthephyra acanthitelsonis. The specimen was collected under the framework of the project “ABRACOS 2” (Acoustic along the BRazilian COast), on board of R/V Antea in April 2017, using a Micronekton net (mesh size of 10 mm) in Rocas Atoll. The specimen female of Holophryxus acanthephyrae was found in pelagic zone in Rocas Atoll, at 630 m depth. This study increases the knowledge on Dajidae family and their host range.

Ecotoxicological responses to chalcopyrite exposure in a proxy for deep-sea hydrothermal vent shrimp: implications for seafloor massive sulphide mining

ABSTRACTDeep-sea mineral prospecting has raised concerns regarding potential ecotoxicological impacts of deep-sea mineral extraction. Although metal mineral phases are predicted to exhibit low bioavailability, few data explore the relative toxicity of mineral phases and dissolved constituent metals. Acute 96 h chalcopyrite (CuFeS2) (<250 µm grain size) exposures using the shallow-water ecophysiological model organism Palaemon varians as an ecotoxicological proxy for deep-sea hydrothermal vent shrimp revealed no effect in both lethal and sublethal assays up to 2.888 g L−1, suggesting that chalcopyrite is not bioavailable. Deep-sea species, therefore, appear at greater ecotoxicological risk from dissolved metals during seafloor massive sulphide (SMS) mining. Consequently, an approach combining modelling the release, and spatial and temporal dilution of dissolved metals during SMS mining, with data on sublethal effects of dissolved metals on shallow-water proxies, may best constrain the potential ecotoxicological impacts of SMS mining, and deliver ecotoxicological threshold concentrations for active SMS extraction.

Magnetically tunable oil droplet lens of deep-sea shrimp

In this study, the tunable properties of a bio-lens from a deep-sea shrimp were investigated for the first time using magnetic fields. The skin of the shrimp exhibited a brilliantly colored reflection of incident white light. The light reflecting parts and the oil droplets in the shrimp’s skin were observed in a glass slide sample cell using a digital microscope that operated in the bore of two superconducting magnets (maximum strengths of 5 and 13 T). In the ventral skin of the shrimp, which contained many oil droplets, some comparatively large oil droplets (50 to 150 μm in diameter) were present. A distinct response to magnetic fields was found in these large oil droplets. Further, the application of the magnetic fields to the sample cell caused a change in the size of the oil droplets. The phenomena observed in this work indicate that the oil droplets of deep sea shrimp can act as lenses in which the optical focusing can be modified via the application of external magnetic fields. The results of this study will make it possible to fabricate bio-inspired soft optical devices in future.

Systematics and biology of the blue lanternfish, Diaphus coeruleus from the south-eastern Arabian Sea

The paper presents the first detailed study on systematics, otolith structure and biology of Diaphus coeruleus, from the south-eastern Arabian Sea. The closely related and co-inhabiting species D. coeruleus and D. watasei are distinguished on the basis of morphometric, meristic and otolith characters. Analysis of gut content revealed that these fishes mainly feed on deep sea squids and shrimps. Six maturation stages of gonads are identified in males (immature, quiescent, mature, ripe, spawning and spent) and five stages (immature, quiescent, mature, ripening and spawning stages) in females. Overall sex ratio deviated in favour of males (1 male: 0.2 female) and the mean fecundity was 2150 ± 353 eggs. The length-weight relationship shows an overall isometric growth in males with N = 76 and b = 3.13 and for females with N = 17 and suggests negative allometric growth (b = 1.719). Otolith length (LO) and otolith weight (WO) are positively correlated to standard body length (LS) and body weight (BW).

The deep-sea commercial caridean shrimp, Heterocarpus woodmasoni (Crustacea: Decapoda: Panalidae), with description of a new species from the western Pacific Ocean

The availability of fresh specimens of the commercial, deep-sea pandalid shrimp, Heterocarpus Alcock, 1901, from India revealed that material referred to this species from India and the western Pacific Ocean have distinct differences in coloration, morphology, and genetic divergence. Although the syntypes of cannot be located now, a color photograph of a typotypic specimen from the Andaman Sea allowed the determination of the Indian form as the true woodmasoni. To stabilize the taxonomy in the H. woodmasoni species group, a neotype is selected for from an Indian specimen with both coloration and molecular barcoding information. The western Pacific form is described as a new species, Heterocarpus fascirostratus sp. nov., which differs from in having a banded rostrum, eggs reddish brown instead of greenish brown, lacking rostral crest, armed usually with fewer dorsolateral spines on the telson, the overhanging spine on the abdominal somite III not markedly recurved downwards, and a rather straight postantennal carina.

The Effect of Natural Osmolyte Mixtures on the Temperature-Pressure Stability of the Protein RNase A

Abstract In biological cells, osmolytes appear as complex mixtures with variable compositions, depending on the particular environmental conditions of the organism. Based on various spectroscopic, thermodynamic and small-angle scattering data, we explored the effect of two different natural osmolyte mixtures, which are found in shallow-water and deep-sea shrimps, on the temperature and pressure stability of a typical monomeric protein, RNase A. Both natural osmolyte mixtures stabilize the protein against thermal and pressure denaturation. This effect seems to be mainly caused by the major osmolyte components of the osmolyte mixtures, i.e. by glycine and trimethylamine-N-oxide (TMAO), respectively. A minor compaction of the structure, in particular in the unfolded state, seems to be largely due to TMAO. Differences in thermodynamic properties observed for glycine and TMAO, and hence also for the two osmolyte mixtures, are most likely due to different solvation properties and interactions with the protein. Different from TMAO, glycine seems to interact with the amino acid side chains and/or the backbone of the protein, thus competing with hydration water and leading to a less hydrated protein surface.

Larval development to the first eighth zoeal stages in the deep-sea caridean shrimp Plesionika grandis Doflein, 1902 (Crustacea, Decapoda, Pandalidae).

The larvae of the deep-sea pandalid shrimp Plesionika grandis Doflein, 1902 were successfully reared in the laboratory for the first time. The larvae reached the eighth zoeal stage in 36 days, both of which are longest records for the genus. Early larval stages of P. grandis bear the general characters of pandalid shrimps and differ from the other two species of Plesionika with larval morphology known in the number of spines on the anteroventral margin of carapace, number of tubercles on antennule, endopod segmentation in antenna, and third maxilliped setation. Although members in Plesionika are often separated into species groups, members of the same species group do not necessarily have similar early larval morphology. Since the zoea VIII of P. grandis still lacks pleopods and fifth pereiopod, this shrimp likely has at least 12 zoeal stages and a larval development of 120 days.

The complete mitochondrial genome of the alvinocaridid shrimp Shinkaicaris leurokolos (Decapoda, Caridea): Insight into the mitochondrial genetic basis of deep-sea hydrothermal vent adaptation in the shrimp

Deep-sea hydrothermal vent is one of the most extreme environments on Earth with low oxygen and high levels of toxins. Decapod species from the family Alvinocarididae have colonized and successfully adapted to this extremely harsh environment. Mitochondria plays a vital role in oxygen usage and energy metabolism, thus it may be under selection in the adaptive evolution of the hydrothermal vent shrimps. In this study, the mitochondrial genome (mitogenome) of alvinocaridid shrimp Shinkaicaris leurokolos (Kikuchi & Hashimoto, 2000) was determined through Illumina sequencing. The mitogenome of S. leurokolos was 15,903bp in length, containing 13 protein-coding genes, 2 rRNAs, and 22 tRNAs. The gene order and orientation were identical to those of sequenced alvinocaridids. It has the longest concatenated sequences of protein-coding genes, tRNAs and shortest pooled rRNAs among the alvinocaridids. The control regions (CRs) of alvinocaridid were significantly longer (p<0.01) than those of the other caridaen. The alignment of the alvinocaridid CRs revealed two conserved sequence blocks (CSBs), and each of the CSBs included a noncanonical open reading frame (ORF), which may be involved in adjusting mitochondrial energy metabolism to adapt to the hydrothermal environment. Phylogenetic analysis supported that the deep-sea hydrothermal vent shrimps may have originated from those living in shallow area. Positive selection analysis reveals the evidence of adaptive change in the mitogenome of Alvinocarididae. Thirty potentially important adaptive residues were identified, which were located in atp6, cox1, cox3, cytb and nad1–5. This study explores the mitochondrial genetic basis of hydrothermal vent adaptation in alvinocaridid for the first time, and provides valuable clues regarding the adaptation.

Photophore counts in the deep-sea commercial shrimp Aristeus alcocki Ramadan, 1938 (Crustacea: Decapoda: Aristeidae), with a revised key to the Indo-West Pacific species of the genus.

The availability of abundant fresh material of Aristeus alcocki Ramadan, 1938 from India allowed the evaluation of the variation in the numbers of photophores on the pereiopods in this species, as well as other diagnostic characters for species discrimination. Although the pereiopodal photophore counts in A. alcocki largely overlap with those of A. semidentatus Bate, 1888, it is found that A. alcocki is unique in the Indo-West Pacific species of the genus by the lower end of the cervical carina considerably farther away from the branchiostegal carina. Molecular genetic analysis confirmed the distinct taxonomic status of the six currently known species in this genus from the Indo-West Pacific and a revised key is provided for distinguishing them.

Deep-Sea Phylogeographic Structure Shaped by Paleoenvironmental Changes and Ongoing Ocean Currents Around the Sea of Japan in a Crangonid Shrimp, Argis lar.

The deep-sea crangonid shrimp, Argis lar, is a highly abundant species from the northern Pacific Ocean. We investigated its phylogeographic and demographic structure across the species' extensive range, using mitochondrial DNA sequence variation to evaluate the impact of deep-sea paleoenvironmental dynamics in the Sea of Japan on population histories. The haplotype network detected three distinct lineages with allopatric isolation, which roughly corresponded to the Sea of Japan (Lineage A), the northwestern Pacific off the Japanese Archipelago (Lineage B), and the Bering Sea/Gulf of Alaska (Lineage C). Lineage A showed relatively low haplotype and nucleotide diversity, a significantly negative value of Tajima's D, and a star-shaped network, suggesting that anoxic bottom-water in the Sea of Japan over the last glacial period may have brought about a reduction in the Sea of Japan population. Furthermore, unexpectedly, the distributions of Lineage A and B were closely related to the pathways of the two ocean currents, especially along the Sanriku Coast. This result indicated that A. lar could disperse across shallow straits through the ocean current, despite their deep-sea adult habitat. Bayesian inference of divergence time revealed that A. lar separated into three lineages approximately 1 million years before present (BP) in the Pleistocene, and then had been influenced by deep-sea paleoenvironmental change in the Sea of Japan during the last glacial period, followed by a more recent larval dispersal with the ocean current since ca. 6 kilo years BP.