Large Squid Research Articles

Peluang investasi dan daya dukung lingkungan usaha penangkapan ikan di Kabupaten Majene Provinsi Sulawesi Barat

Background: Majene Regency, which is located in West Sulawesi Province, is part of the Republic of Indonesia State Fisheries Management Area (WPPNRI) 713. It has a coastline length of approximately 125 km2, a sea area of more than 13,124 km2, and a land area of around 947.84 km2. The potential fish resources are 1,026,599 million tonnes per year, mainly consisting of small pelagic fish, large pelagic fish, demersal fish, coral fish, penaeid shrimp, lobsters, crabs, and squid. Methods: This research uses scientific literature sources, government publications, policy documents, academic databases including scientific journals, and books to obtain a comprehensive and up-to-date view. Findings: Data shows that capture fisheries production in Majene Regency produces 7,458 tonnes of marine fisheries products. Conclusion: This increased from the previous year's 4.36 percent from 2017 to 2018. The largest marine fisheries production came from Banggae District, contributing 21.87 percent to Majene Regency's fisheries production. Aquaculture production originating from ponds decreased by 46.36 percent from 2017 to 2018. The amount of investment entering Western Province is still relatively low, namely being ranked 30th out of 34 provinces in Indonesia and in last position. out of 5 provinces in Sulawesi.

Life History Patterns of the Atlantic Brief Squid, Lolliguncula brevis (Blainville, 1823), in the Charleston Harbor Estuary, South Carolina, USA

The Atlantic brief squid, Lolliguncula brevis, is a euryhaline cephalopod that inhabits shallow, continental shelf habitats from Argentina to the Bay of Fundy. In the southeastern United States, brief squid can account for a considerable portion of the estuarine animal biomass and are an important component of the diets of species with high priority for management and conservation. Historical data from South Carolina Department of Natural Resources suggest that brief squid exhibit spatially and temporally variable size-frequency distributions within the Charleston Harbor estuary. Prior to this study, however, detailed life history information for this species was lacking in the region. Samples of brief squid were collected monthly at four stations along a salinity gradient within the Charleston Harbor estuary in 2019 to investigate temporal and spatial patterns of abundance, sex, size, and maturity. Season and station were significantly related to brief squid abundance, which was greater for all sexes in spring, summer, and fall than in winter. Catches of brief squid were dominated by immature squid compared with mature squid. Excluding sexually indistinct squid, and across all seasons, significantly more males were collected than females. Mean brief squid size tended to be larger in May than in several other months of the year, largely due to the lower abundance of small squid in that month. Logistic regression analyses indicated that brief squid size-at-maturity occurred at 50.2 mm for males and 59.2 mm for females. The presence of both small and large brief squid throughout the year at all stations supports a pattern of overlapping cohorts, whereas the continual presence of immature brief squid at all stations suggests asynchronous recruitment. This study provides valuable life history information that can be used to support the conservation and management of organisms that are either prey or predators of brief squid within the Charleston Harbor estuary. Further research over multiple years and within other estuaries in the Georgia Bight is needed, however, to determine how the life history patterns observed in this study apply more broadly across the region.

Distribution and geographic differences in stable isotope ratios of diamond squid Thysanoteuthis rhombus (Cephalopoda: Thysanoteuthidae) in Japanese waters

AbstractDiamond squid Thysanoteuthis rhombus (Troschel, 1857), which can grow to a dorsal mantle length of ~100 cm in 1 year, is an important fisheries resource in subtropical and temperate waters worldwide. Around Japan, it is an important resource in the East China Sea, Sea of Japan, and western North Pacific Subtropical Gyre, including the Kuroshio area. It is not known if linkages occur between these habitats. To clarify the species distribution, we estimated the habitat of young squid using a generalized additive model based on trawl surveys and analyzed carbon and nitrogen stable isotope ratios (δ13C and δ15N) in tissue samples. Based on trawl observations, young squid were distributed around northeastern Taiwan and the Okinawa Islands in June–July and in the Sea of Japan and the Kuroshio extension areas in August–September. We observed ontogenetic changes in the stable isotope ratios. The δ15N values in large diamond squid (dorsal mantle length > 400 mm) were significantly lower in the Pacific than those in other areas. Considering that the δ15N of forage fish is low in the Pacific and high in the East China Sea and Sea of Japan, large diamond squid in the northwest Pacific presumably have two distinct habitats.

TRAINING ON MAKING RUMPON AS FISH HABITAT FOR FISHERMAN IN UJONG BLANG VILLAGE LHOKSEUMAWE CITY

Indonesia has a very diverse fishery resource potential, including large pelagic, small pelagic, demersal, penaeid shrimp, crabs, crabs, squid and reef fish. Fishery is one sector that is relied upon for Indonesia's future development, because it can provide an economic impact to some of Indonesia's population. The national capture fisheries are still characterized by small-scale capture fisheries. This can be proven by the existence of capture fisheries in Indonesia which is still dominated by small-scale capture fisheries, namely around 85%, and only around 15% is carried out by larger-scale fisheries. the use of fishing gear that is not environmentally friendly encourages over-exploitation of fishery resources. rumpon are a tool for collecting fish. The use of rumpon as fishing aids has long been recognized by Indonesian fishermen. The success of rumpon as fishing aids need not be doubted anymore, because rumpon are very effective as a tool to collect fish to make it easier to catch. The method used in this activity is to conduct counseling in the form of providing a theoretical view of the positive impact in the field of rumpon. After conducting counseling, the training will continue with how to make rumpon properly and correctly.

Dietary shifts and niche partitioning throughout ontogeny reduce intraspecific competition in a pelagic generalist predator

Patterns of feeding strategy change throughout ontogeny according to size-specific abilities and requirements. Characterizing the extent and potential repeated occurrence of dietary differences within the population can improve understanding of the intraspecific predation regime and population dynamics. Here, we investigated size-related feeding habits and trophic niche partitioning of an iconic pelagic generalist predator, the jumbo squid Dosidicus gigas, by a combined analysis of morphologic indicators of feeding capability (fin and feeding apparatuses), trophic biochemical tracers (stable isotopes and fatty acids), and stomach contents. Results showed significant variation in prey composition, isotopic values, and fatty acid profiles with size. D. gigas exhibited a shift in diet at approximately 250 mm mantle length (ML). The trophic niche of small (ML ≤ 250 mm) and large (ML > 250 mm) squid revealed low potential for resource overlap, suggesting segregation in terms of spatial and food resources of different size groups. Large individuals tend to feed deeper and on smaller prey to optimize food capture costs and energy benefits. This feeding strategy is likely related to variability in the development of feeding capacity, increasing swimming ability, and metabolic demand as squid grow and may reduce intraspecific competition to improve survival. These results highlight the dietary flexibility of D. gigas and demonstrate that niche differentiation acts as a major factor in a cohort, which may have important implications for their population dynamics and management. In addition, this study demonstrates that using multiple diet tracers can highlight subtle differentiations in diet correlated to growth in a pelagic generalist predator.

Size Related Differences in Organic and Mineral Components of Molluscan Shell

A unique and rare event of consumption of a seabird (aviphagy) was recorded for a Southern Ocean squid in Australian waters. Petrel remains were identified in the stomach contents of a large (518 mm Mantle Length, 3.4 kg) female ommastrephid squid, Todarodes filippovae (Adam 1975) captured off the southern coast of Tasmania, Australia. The remains were identified as to being from either a fairy prion Pachyptila turtur or white-faced storm petrel Pelagodroma marina. This unique observation expands the evidence for aviphagy recorded in other cephalopods to now include squid.

Studying the swift, smart, and shy: Unobtrusive camera-platforms for observing large deep-sea squid

The legend of the “kraken” has captivated humans for millennia, yet our knowledge of the large deep-sea cephalopods that inspired this myth remains limited. Conventional methods for exploring the deep sea, including the use of nets, manned submersibles, and remotely operated vehicles (ROVs), are primarily suited for studying slow-moving or sessile organisms, and baited camera-traps tend to attract scavengers rather than predators. To address these issues, unobtrusive deep-sea camera platforms were developed that used low-light cameras, red illuminators, and bioluminescence-mimicking lures. Here, we report on several opportunistic deployments of these devices in the Wider Caribbean Region where we recorded several encounters with large deep-sea squids, including the giant squid Architeuthis dux Steenstrup 1857, Pholidoteuthis adami Voss 1956, and two large squid that may be Promachoteuthis sp. (possibly P. sloani Young et al. 2006). These species were recorded between depths of 557 and 950 m. We estimate the Mantle Lengths (ML) of Promachoteuthis were ~1.0 m, the ML of the Pholidoteuthis was ~0.5 m, and the ML of the Archtiteuthis was ~1.7 m. These encounters suggest that unobtrusive camera platforms with luminescent lures are effective tools for attracting and studying large deep-sea squids.

Dietary fatty acid analyses of the squid Idioteuthis cordiformis: further evidence for predation on deepwater sharks

Idioteuthis cordiformis is the largest deepwater mastigoteuthid squid in the southern Pacific Ocean. Signature fatty acid (FA) and lipid class analysis was carried out on the digestive gland, fins and caecum oil of 18 individuals of I. cordiformis caught in the waters off southern Australia during late 2004. Lipid classes varied between the tissues and oil samples, with sex not being an important factor. The presence of hydrocarbons within the digestive gland and caecum was noteworthy, as high proportions of this lipid class are generally only common in the livers of many deepwater sharks. Monounsaturated FAs dominated the digestive gland and caecum oil, while the fin had high values of both saturated and polyunsaturated FAs. FA profiles of I. cordiformis were compared to profiles of potential prey species (sharks, small and large fish, crustaceans and squid) using Bray-Curtis similarity coefficients. Analysis of the digestive gland and caecum oil FA profiles revealed a close match with the following prey: myctophids (Lampanyctodes australis, Electrona paucirastra, Symbolophorus barnardi), the dragon fish Stomias boa, the smooth oreo Pseudocyttus maculatus and the deepwater sharks Etmopterus baxter, Dalatias licha, Centroselachus crepidater, Centroscymnus coelopsis and Centrophorus zeehaani. The fin FA profile did not match closely to any potential prey and was most similar to other squid mantle tissue. Based on the results of this study, I. cordiformis has a broad diet spectrum of teleost fish and deepwater sharks and occupies a high trophic position.

Evidence of interactions between white sharks and large squids in Guadalupe Island, Mexico

Shark-cephalopod interactions have been documented in trophic ecology studies around the world. However, there is little information about the encounters between white sharks Carcharodon carcharias and squids in the eastern North Pacific Ocean. Here we provide evidence of interactions between white sharks and large squids in the waters of Guadalupe Island, Mexico. Through the use of non-invasive techniques, we found the presence of evident scars made by large squids on the body of the white sharks, mainly on the head and trunk, of at least 14 sharks recorded during August–December in the years 2008, 2012, 2013, 2017 and 2019. The mean length of the white sharks was 3.7 m (SD ± 0.6; total length), although the majority of the sharks with scars were adult and subadult males (n = 9; 64%). One of these males was photographically recaptured during the same season in which the individual showed new scars, confirming that the squid-white shark interaction likely occurs near Guadalupe Island. Our results highlight the importance of the twilight zone for white sharks and the use of shared habitat and trophic interactions between squid and white sharks, in which future ecosystem studies should consider both species for management and conservation purposes.

Stable isotope patterns of mesopelagic communities over two shallow seamounts of the south-western Indian Ocean

The stable carbon (δ13C) and nitrogen (δ15N) isotope values of soft tissues of micronekton (crustaceans, squid, mesopelagic fish) and zooplankton were measured from organisms collected on the RV Antea at two seamounts located in the south-western Indian Ocean: La Pérouse (summit depth ~60 m) and “MAD-Ridge” (thus named in this study; summit depth ~240 m). Surface particulate organic matter (POM-Surf) showed higher δ13C at the more productive MAD-Ridge than at the oligotrophic La Pérouse seamount. Particulate organic matter and zooplankton were depleted in 15N at La Pérouse pinnacle compared with MAD-Ridge. Gelatinous organisms and crustaceans occupied the lowest and intermediate trophic levels (TL ~2 and 3 respectively) at both seamounts. Mesopelagic fish and smaller-sized squid sampled at both seamounts occupied TL ~3 to 4, whereas the large nektonic squid, Ommastrephes bartramii, collected at MAD-Ridge only, exhibited a TL of ~5. The δ15N values of common open-water mesopelagic taxa were strongly influenced by specimen size and feeding habits at both seamounts, with an increase in δ15N values with increasing size. Carnivorous fish species sampled exclusively over the seamounts’ flanks and summits exhibited TL values of ~4, irrespective of their wide size ranges. The work could not demonstrate any differences in δ13C values of mesopelagic fish between the seamounts and the surrounding oceanic areas. The study segregated clusters of mesopelagic organisms according to their δ13C and δ15N values, with variations in stable isotope values reflecting a complex range of processes possibly linked to productivity as well as biological and ecological traits of the species (size and feeding mode).

Phylogenetic relationships and cryptic species in the genus Sthenoteuthis (Cephalopoda: Ommastrephidae) in the South China Sea

Large squids of the genus Sthenoteuthis are commercially relevant species that include two truly oceanic squids. They are large nektonic predators being widely distributed throughout tropical and subtropical waters of the Atlantic and Indo-Pacific Ocean. The present study investigates different morphs varying in size at maturity, and assesses the genetic divergence in Sthenotheutis in relation to geographic patterns in the South China Sea. We obtained sequences using a mitochondrial (cytochrome c oxidase subunit I) and a nuclear (Histone H3) gene marker from 111 individuals in 23 locations of the South China Sea. In combination with sequences available in public databases, we performed tests on DNA taxonomy, mostly based on molecular phylogenies. Our results suggest that the genus Sthenoteuthis includes at least three species. The Indo-Pacific purpleback squid Sthenoteuthis oualaniensis contains at least two genetically distinct lineages that can be considered separate species, a dwarf species and a medium-sized species, separated by both the mitochondrial marker and the more conserved nuclear marker. We also assessed whether the few cases of mitonuclear discordance could be the result of genetic introgression and past hybridization or incongruence lineage sorting. The medium-sized species is more widely distributed and dominant in the South China Sea than the dwarf species. The medium-sized species inhabits the whole South China Sea, whereas the dwarf species is restricted to the equatorial waters of the South China Sea. The medium-sized species has two further genetic clades, one distributed in the East Pacific Ocean and the other in the South China Sea. This high level of genetic differentiation is in agreement with the discriminant analysis on the morphological measurements, clearly separating the dwarf and medium-sized species, indicating the presence of a complex of pseudo-cryptic species in S. oualaniensis, clearly identifiable by differences in DNA sequences and in body size, and statistically differentiated in their body measurements.

Komposisi Hasil Tangkapan dan Tingkat Keramahan Jala Cumi (Cast Net) di PPN Kejawanan Cirebon Jawa Barat

Pelabuhan Perikanan Nusantara (PPN) Kejawanan Cirebon berada di bagian Timur Jawa Barat, merupakan pelabuhan tipe B yang didominasi oleh kapal dengan alat tangkap jala cumi (cast net) dengan jumlah sebanyak 123 unit kapal. Tujuan dari penelitian ini adalah manganalisis komposisi hasil tangkapan dan tingkat keramahan alat tangkap jala cumi (cast net) berdasarkan komposisi hasil tangkapan utama dan sampingan. Pengumpulan data dilakukan melalui wawancara dan survei. Data hasil tangkapan ikan dikumpulkan dari unit alat tangkap jala cumi (cast net) sebanyak 10 (sepuluh) unit kapal pada tahun 2018. Analisis data meliputi komposisi jenis hasil tangkapan dan tingkat keramahannya. Hasil penelitian menunjukan bahwa alat tangkap jala cumi (cast net) dengan komposisi hasil tangkapan didominasi oleh cumi-cumi sebesar 97% dan sisanya sebanyak 3% terdiri dari ikan lemuru, layang dan teri. Adapun ukuran hasil tangkapan cumi-cumi yang didaratkan di PPN Kejawanan Cirebon memiliki ukuran dengan kategori cumi besar 27-30 cm dengan jumlah total 79.324,64 kg dan cumi ukuran kecil 1-7 cm dengan jumlah total 18.411,29 kg. Nilai tingkat keramahan lingkungan pada alat tangkap jala cumi (cast net) diperoleh dengan jumlah nilai total 30. Berdasarkan nilai tersebut maka alat tangkap jala cumi (cast net) dikategorikan sebagai alat tangkap yang sangat ramah lingkungan.

Seasonal variation of background formaldehyde content in large squid from scientific research research vessel

The background formaldehyde (FA) in large squid is determined through high performance liquid chromatography (HPLC). Its seasonal variation was further investigated. In autumn and summer, background FA content in Todarodes pacificus was higher, with the mean value up to 36.8 mg/kg in September. This study provide scientific data for the monitoring management of FA during the circulation and sale of squid.

Retrospective Study of Traumatic Intra-Interspecific Interactions in Stranded Cetaceans, Canary Islands.

Aggressive encounters involving cetacean species are widely described in the literature. However, detailed pathological studies regarding lesions produced by these encounters are scarce. From January 2000 to December 2017, 540 cetaceans stranded and were necropsied in the Canary Islands, Spain. Of them, 24 cases of eight species presented social traumatic lesions produced by cetaceans of the same or different species. All the cases presented severe multifocal vascular changes, 50% (12/24) presented fractures affecting mainly the thoracic region, 41.7% (10/24) acute tooth-rake marks, 37.5% (9/24) undigested food in the stomach, 33.3% (8/24) tracheal edema, and 12.5% (3/24) pulmonary perforation. In 10 cases with tooth-rake marks, the distance between the teeth, allowed us to further identify the aggressor species: four cases were compatible with killer whales (Orcinus orca) affecting three species [pigmy sperm whale (Kogia breviceps), Cuvier's beaked whale (Ziphius cavirostris), and short-finned pilot whale (Globicephala macrorhynchus)] and four cases compatible with common bottlenose dolphins (Tursiops truncatus) affecting two species [short-beaked common dolphin (Delphinus delphis) and Atlantic spotted dolphin (Stenella frontalis)]. We also described two cases of intraspecific interaction in stripped dolphin (Stenella coeruleoalba). Microscopically, 70.8% (17/24) of the cases presented acute degenerative myonecrosis, 66.7% (14/21) presented vacuoles in the myocardiocytes, 36.8% (7/19) pigmentary tubulonephrosis, 31.6% (6/19) cytoplasmic eosinophilic globules within hepatocytes, 21.4% (3/14) hemorrhages in the adrenal gland, and 17.3% (4/23) bronchiolar sphincter contraction. The statistical analysis revealed that deep divers, in good body condition and nearby La Gomera and Tenerife were more prone to these fatal interactions. Additionally, in this period, three animals died due to an accident during predation: a false killer whale (Pseudorca crassidens) died because of a fatal attempt of predation on a stingray, and two Risso's dolphins (Grampus griseus) died as a consequence of struggling while predating on large squids.

The Sea of Amakusa playing the role of a distributor of swordtip squid (Uroteuthis edulis) migrating from the East China Sea to the east and west sides of Japan

We investigated the monthly numbers of tracers moving from the southern East China Sea to the east side of Japan via the Sea of Amakusa, on the west side of Japan, by tracer experiments. We estimated the migratory route of large Swordtip squid (Uroteuthis edulis) caught in Sagami Bay, on the east side of Japan, by the micro-increment counts and variation of strontium:calcium ratios of the statoliths to test our hypothesis that the Sea of Amakusa plays the role of a distributor of this species to the east and west sides of Japan. Results of the monthly numbers of the tracers were generally consistent with the season of peak catches on the east side. The older tracers reaching the east side of Japan were found to have passed through the Sea of Amakusa at larger rates. Moreover, the estimated empirical water temperature history of the large squid caught in Sagami Bay showed two peaks, in winter and early summer, implying that the squid experienced the Kuroshio current twice and that during spring, they stayed in waters whose temperature was a few degrees lower than that of the Kuroshio; that is, in the Sea of Amakusa. Frequent and extensive marine observations will be needed to fully understand the distribution of this species around Japan.

Distribution, age and growth of the diamondback squid, Thysanoteuthis rhombus (Cephalopoda: Thysanoteuthidae) from the tropical Arabian Sea

Individuals in all life stages of the large oceanic diamondback squid Thysanoteuthis rhombus were observed in the southeastern Arabian Sea. A total of 82 individuals were collected from the Arabian Sea between February 2013 and December 2018. The length-weight relationship follows an allometric growth pattern. Age and growth were estimated by statolith increment analysis (n = 77) and demonstrated a rapid growth rate ranging from 1.42 to 4.80 mm dorsal mantle length (DML)/day. Based on back calculated hatch dates, T. rhombus spawned from May to December with a peak in July. Male and female squids matured at 6 months of age. The oldest individual was a mature female (655 mm DML) that was 220 days old with a growth rate of 2.97 mm DML/day. Differences in size-wise (DML) instantaneous growth rates were evident. Stomach content analysis revealed that fish and squid were the major prey of adults and sub-adults, while in juveniles, crustaceans were the dominant prey item. Ontogenetic differences in the diet were apparent.

Got Squid? Changes in the Ecological State of the Gulf of California Since the 1940 Steinbeck-Ricketts Expedition with a Focus on Humboldt Squid

Got Squid? Changes in the Ecological State of the Gulf of California Since the 1940 Steinbeck-Ricketts Expedition with a Focus on Humboldt Squid W. F. Gilly (bio), Unai Markaida (bio), Carlos Robinson (bio), and Bilin Liu (bio) Introduction Although the exact number of invertebrate species collected by Steinbeck and Ricketts in conjunction with the 1940 Sea of Cortez expedition on the Western Flyer is uncertain (Brusca, this volume), it is clear that the number of cephalopod species observed was small—fewer than 1% of the species collected. In particular, Dosidicus gigas, the Humboldt or jumbo flying squid, was apparently not seen during the expedition. This stands in contrast to the remarkable ease with which this species was observed north of Santa Rosalía in the Guaymas Basin region of the Gulf of California during a 2004 retracing of the 1940 expedition during the same time of year and using the same type of vessel and similar observational methods (Sagarin et al. 2008). Dosidicus is a monocyclic, short-lived species that matures only once at a broad size range. During favorable years, large squid prevail and commonly reach a mantle length (ML) of >60 cm and a mass of 20 kg or more at maturity, with a life span of 1.5–2.0 years in the Sea of Cortez (Hoving et al. 2013). [End Page 411] Large squid of this sort supported the third- or fourth-largest commercial fishery in Mexico for the decade preceding the 2004 trip, with the vast majority of landings coming from the Guaymas Basin area (Rosa et al. 2013). These factors made it hard for even a casual observer in the Central Gulf to be unaware of Dosidicus gigas between 1995 and 2009. It thus seems that large Humboldt squid were likely not to have been abundant in the Gulf of California in the spring of 1940, and reasons for the apparent change in the status of Humboldt squid since that time have been discussed without reaching any firm conclusion (Sagarin et al. 2008). Shortly after publication of the 2008 paper, a strong El Niño in 2009–2010 influenced the Central Gulf in a profound way. Humboldt squid in this region responded to this climatic anomaly by taking on a characteristic of the tropical portion (Costa Rica to Ecuador) of their large range, where squid mature at extremely small size (~30 cm ML, ~0.1 kg) and live for only about 6 or months (Hoving et al. 2013). In addition, commercial landings crashed. Both phenomena also occurred in conjunction with the strong El Niño of 1997–1998 (Bazzino et al. 2007; Morales-Bojórquez and Nevárez-Martínez 2010). Although recovery of landings and return to a large size at maturity occurred within a few years after the 1997–1998 event (Markaida 2006), recovery has not occurred during the years after El Niño 2009–2010, a period characterized in the Central Gulf by reduced wind-driven upwelling and productivity (Robinson et al. 2016) and, as documented in the present paper, increased warming at depth (see also Frawley et al. 2019). Another strong El Niño occurred in 2015–2016. These observations suggest that the ecological state of the Gulf of California can show drastic, long-lasting alterations that involve the size of Humboldt squid. Although small Humboldt squid are probably still abundant in the Gulf (Hoving et al. 2013 and unpublished jigging data), they are clearly much less obvious (and more difficult to capture by jigging) than larger squid were a decade ago. This new awareness is relevant to the question of why Steinbeck and Ricketts did not record this species in the Sea of Cortez in 1940. We examine several possibilities in reassessing this question. First, squid may not have been of much interest to the intertidal explorers in 1940, so not much attention was paid to this group. Second, small, juvenile specimens of Dosidicus gigas were in fact collected but misidentified. Third, large Humboldt squid were temporarily absent from the Gulf during their visit because of the effects of El Niño. Fourth, [End Page 412] large (and potentially smaller) squid were absent because of chronically unfavorable...

Amino acid δ13C and δ15N from sclerotized beaks: a new tool to investigate the foraging ecology of cephalopods, including giant and colossal squids

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 624:89-102 (2019) - DOI: https://doi.org/10.3354/meps13002 Amino acid δ13C and δ15N from sclerotized beaks: a new tool to investigate the foraging ecology of cephalopods, including giant and colossal squids Yves Cherel1,*, Paco Bustamante2, Pierre Richard2 1Centre d’Etudes Biologiques de Chizé (CEBC), UMR 7372 du CNRS-La Rochelle Université, 79360 Villiers-en-Bois, France 2Littoral, Environnement et Sociétés (LIENSs), UMR 7266 du CNRS- La Rochelle Université, 2 rue Olympe de Gouges, 17000 La Rochelle, France *Corresponding author: cherel@cebc.cnrs.fr ABSTRACT: Combining the use of predators as biological samplers together with measurements of the stable isotopic ratios (δ13CBulk and δ15NBulk) of their sclerotized beaks help investigate foraging ecology of poorly known oceanic cephalopods. However, high chitin content (an amino-sugar macromolecule) lowers beak δ15NBulk values, thus precluding direct isotopic comparison with other tissues and organisms. To overcome the chitin effect, compound-specific isotopic analysis of amino acids (CSIA-AA) was performed on squid beaks. The method was applied on beaks and muscle, and the resulting δ13CAA and δ15NAA values compared between tissues. The usefulness of CSIA was tested by defining the habitat and trophic position (TPCSIA) of squids using their δ13CAA and δ15NAA values. Beak δ13CAA values were reliably measured on 12 AA that included 5 essential and 7 non-essential AA, and δ15NAA values were quantified on at least 7 AA that included 2 source and 4 trophic AA. Importantly, δsup>13CAA and δ15NAA varied little between muscle and lower and upper beaks, and TPCSIA estimates were identical regardless of the tissue considered. Tissue δ13CAA values of both essential and non-essential AA reflected the latitudinal baseline δ13C gradient that occurs in the Southern Indian Ocean, while beak δ15NAA from source and trophic AA allowed the disentangling of the baseline effect from the trophic effect, and thus better calculations of squid TP estimates than from δ15NBulk values. Beak δ13CAA and δ15NAA defined isotopic niches of colossal and giant squids, the 2 largest living invertebrates. In subantarctic waters, they segregate by having species-specific foraging habitats (using δ13CGly or δ15NPhe) and TPCSIA (using δ15NGlx and δ15NPhe). TPCSIA is higher in colossal (4.7) than giant (4.3) squids, and both values compare well with those of myctophid-eaters, suggesting very large squids prey primarily upon small zooplanktivorous fishes. As expected, CSIA-AA overcomes the chitin effect on beaks and it is a powerful tool to investigate trophic interactions of cephalopods. The method has a great potential with arthropods, because chitin is a main component of their exoskeleton but the deleterious effect of chitin is overlooked in isotopic studies focusing on crustaceans and insects. KEY WORDS: Arthropod · Carbon · Chitin · CSIA · Habitat · Nitrogen · Stable isotope · Trophic position Full text in pdf format PreviousNextCite this article as: Cherel Y, Bustamante P, Richard P (2019) Amino acid δ13C and δ15N from sclerotized beaks: a new tool to investigate the foraging ecology of cephalopods, including giant and colossal squids. Mar Ecol Prog Ser 624:89-102. https://doi.org/10.3354/meps13002 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 624. Online publication date: August 15, 2019 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2019 Inter-Research.

Migratory routes of different sized swordtip squid (Uroteuthis edulis) caught in the Tsushima Strait

Swordtip squid (Uroteuthis edulis) of various sizes are caught on an almost daily basis from early spring to late autumn in the eastern Tsushima Strait and southern Sea of Japan. In this study, we estimated the migratory routes of different sized squid jigged in the Tsushima Strait using statolith analyses, information on seawater temperature distributions and currents, and tracer experiments. Estimates of age and historic water temperatures suggested that both small and large squid hatch in the southern East China Sea and are then transported northeastward with the currents to the northern Kuroshio region. Following this, the small squid are transported north-northwestward to offshore waters, from where many of the squid enter the southern Sea of Japan and some move into coastal waters in the eastern strait, whereas large squid slowly move northward from the northernmost part of the Kuroshio region. Based on these distributions, it is likely that the small squid remain immature due to insufficient water temperatures over shorter durations, whereas the large squid mature in the Kuroshio region. Since migratory routes affect fishing ground formation, this information is important for both efficient fishing operations and stockmanagement of this species.

Superconducting devices based on coherent operation of Josephson junction arrays above 77K

Arrays of Josephson junctions operating coherently at 77K seem to be the ideal candidates for re-shaping the future of the electronics industry. Their advantages over their semiconducting counterparts (higher operating speed, lower power consumption/electronic noise) can be exploited in practice because of their practicality: cooling down to 77K is both cheap and easy to handle. These developments naturally fit into the increasing interest of some semiconductor technologies in lower operation temperatures. Therefore, it looks attractive to link semiconductor and 77K superconductor technologies to improve system level performance. Currently, however, in the vast majority of applications 4.2K superconducting technology is used as it provides significantly superior performances relative to devices build in the 77K technology. Recent significant improvements in the performance of superconducting devices operating as 77K, as well as, in their fabrication technologies may change all that. Several such examples will be considered here. Firstly, when coherency is achieved in large series SQUID-arrays magnetic flux sensors or voltage amplifiers can be build having record values for their output voltage and flux noise sensitivities outperforming even single SQUID-based devices operating at 4.2 K. Secondly, when coherency is achieved in parallel SQUID-arrays placed in a uniform magnetic field B, B-field tuned microwave generators can be build. Large parallel SQUID arrays were also implemented to achieve record values for current amplification at 77K, highly efficient ratchets with unidirectional magnetic vortices motion and integrated nano-magnetic sensors.