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  • Frequent occurrence of tetrodotoxin in the marine gastropod Nassarius glans causing a food poisoning in Khanh Hoa province, Vietnam in 2020

    Dao, Viet Ha; Le, Ho Khanh Hy; Pham, Xuan Ky; Bui, Quang Nghi; Nguyen, Phuong Anh; Phan, Bao Vy; Doan, Thi Thiet (2023)
    Vietnam journal of marine science and technology
    A fatal neurotoxic poisoning case happened in Khanh Hoa province in 2020 after eating a certain number of marine gastropods, later identified as Nassarius glans, one of the common marine gastropods in Vietnam. As the remaining causative food in the incident, 62 specimens were collected to examine tetrodotoxin toxicity individual variation and frequency of toxic specimens by using HILIC/MS-MS analysis. 100% of studied specimens exhibited toxicity (556 ± 821 MU/g) beyond the regulatory level of consumption (10 MU/g) for puffer(fish) recommended in Japan and extensive variation (18–4,046 MU/g). The result pointed out that only 5 g of soft tissue from N. glans (equivalent to 2–3 specimens) containing maximum toxicity detected in the present study may cause human death if consumed. Fhe first time, this study identified TTXs in the gastropods as a causative toxin in the poisoning in Vietnam. Moreover, 65.5% of studied specimens with high toxicity higher than 100 MU/g, including 16.1%, showing extremely high toxicity (> 1,000 MU/g). The results suggested that this gastropod is quite dangerous for human consumption and should be alerted to public awareness.
  • Metabolites from the soft coral -associated bacterium Micrococcus sp. strain a-2-28

    Pham, Thi Mien; Wiese, Jutta; Dao, Viet Ha (2023)
    Vietnam journal of marine science and technology
    The marine actinomyces Micrococcus was the most common bacterium among the isolates corals, sponges, and alga isolates. Only a few investigations of natural compounds from Micrococcus sp. were reported previously. This study implicated the soft coral-associated Micrococcus sp. strain A-2-28 (following relative Micrococcus flavus LW4T) for large-scale cultivation, chemical analyses, and biological activities. Whereas crude extract of the strain A-2-28 inhibited only Staphylococcus epidermidis, metabolites profiles and pure compounds from strain A-2-28 showed that this strain produced phytohormone (IAA), metabolized some new compounds which were almost inactive for biological tests. This work suggested that it is possible to plan a new strategy for improving coral health and resilience though their associated microbial.
  • Status and temporal change in the distribution of seagrass beds andcoral reefs in the waters of Phu Quoc islands, Kien Giang province

    Nguyen, Van Long; Tong, Phuoc Hoang Son (2023)
    Vietnam journal of marine science and technology
    To assess the status and changes in the distribution of seagrass beds and coral reefs in Phu Quoc from 2005 to 2018, we utilized high-resolution multi-spectrum satellite images, aerial photographs, and Google maps. We collected data from three time periods: 2005 (using ASTER with 15 m resolution), 2010 (using SPOT5 with 10 m resolution), and 2018 (using SENTINEL-2 with 10 m resolution). We also conducted an accuracy assessment of 78 key sites in March-April 2019, representing corals (25 sites), seagrasses (28 sites), rocks (8 sites), and sand (12 sites) through SCUBA diving. The results showed that in 2018, the waters of Phu Quoc contained 513 ha of coral reefs and 10,035 ha of seagrass beds, with 290 ha of coral reefs and 9,185 ha of seagrass beds located within the Phu Quoc marine protected area. While the area of coral reefs remained stable between 2005 and 2018, the seagrass beds experienced a significant decline of 652 ha (6.1%), with most losses occurring at Bai Vong (501 ha; 4.69%), Ong Doi cape - Dam Ngoai island (55 ha; 0.52%), Mot Island and Vinh Dam (42 ha; 0.4% each), and Da Chong cape (12 ha; 0.12%). This decline is largely due to recent infrastructure development for community and tourism purposes, which has caused the degradation of seagrass beds.
  • Trace metal contamination of discharge water in the northeast Mediterranean Sea

    Gurlek, Ozlem Guner; Ergenler, Ayşegul; Turan, Funda (2023-12-26)
    Pakistan Journal of Marine Sciences
    The contamination with trace metals brought on by anthropogenic activity is one of the main issues impacting the health of the environment. The inherent pressures on marine ecosystems and the individuals who depend on marine ecosystems for nourishment, industry, and advantage are both being seriously threatened by trace metal pollution in coastal and marine habitats. This study aimed to find out the accumulation of metals (Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn) in seasonal water samples taken for a year from the Ceyhan River's discharge point into the Northeast Mediterranean. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) measurements of water were performed using an appropriate trace metal-based approach. The relative mean metal concentrations in the water column were in the following order at the sample site: Zn > Fe > Ni > Cr > Cu > Pb> Mn > Cd > Co > Hg. The highest value of Zn in the water column was observed at 90.05810.605 g L-1. The levels of contaminants in the water when compared to international and national water quality standards have been judged to be within the safe drinking range.
  • Heavy metals risk assessment for consumption of wild Mediterranean mussels Mytilus galloprovincialis Lamarck, 1819 along Samsun Coasts of the Black Sea

    Bat, Levent; Yardım, Öztekin; Arıcı, Elif; Hasançavuşoğlu, Zeynep; Öztekin, Ayşah (2023-12-26)
    Pakistan Journal of Marine Sciences
    The present study aimed to determine the concentration of metals in the soft tissue of wild mussels in coastal of Samsun and to assess human consumption. Using inductively coupled plasma mass spectrometry, the quantities of cadmium, mercury, lead, copper, iron, and zinc in Mytilus galloprovincialis were measured. The heavy metals found in Mediterranean mussels are arranged in the following ascending order: Cd < Hg < Pb < Cu < Fe < Zn. Concentrations of toxic metals were safe according to European Commission guidelines and the Ministry of Agriculture, Forestry and Fisheries. According to the estimated daily intake (EDI), eating Mediterranean mussels poses no risks. The target hazard quotients (THQs) in metals are also found <1, which implies no threat to consumers. In conclusion, the current study confirmed that the concentration of heavy metals in the Mediterranean mussels is safe for people intake in terms of their toxicity.
  • First record of alive Asterigerina (Foraminifera: Rotaliida) with note on its distribution and abundance from the coastal area of Pakistan, Northern Arabian Sea

    Gopang, Anila; Farooq, Sumera; Ali, Qadeer Mohammad (2023-12-31)
    Pakistan Journal of Marine Sciences
    Foraminifera is an important group of organisms which is widely used as indicators of environmental change. Not much work on foraminifera has been done on the Arabian margin running along the Pakistan coast. Information on the diversity and distribution of foraminifera is very limited and no information is available from the Balochistan coast. This study is an attempt to explore the diversity and dynamics related to foraminifera at the coast of Baluchistan. This very part of the study is designed to collect information about the zonation, vertical distribution and abundance of the genus Asterigerina at the beach of Ormara, Balochistan. The fossilized form of Asterigerina was previously reported from the sediments of upper Quetta region. This is the first report on the occurrence of alive Asterigerina in the coastal areas of Pakistan.
  • Sexual seasonal growth and mortality of Scaldback, Arnoglossus kessleri Schmidt, 1915 (Pleuronectiformes: Bothidae), caught by experimental beam trawl in the Black Sea, Turkiye

    Bilgin, Sabri; Onay, Hatice (2023-12-26)
    Pakistan Journal of Marine Sciences
    The scaldback, Arnoglossus kessleri, is a small fish that belongs to the Bothidae family and its biology is unknown in the Mediterranean Sea including Aegean Sea, Black Sea and Sea of Marmara. To describe first information on the seasonal von Bertalanffy growth function parameters (SVBGF) using length frequency data for A. kessleri, and also to present first information on indirect methods to estimate natural (M) and total mortality rates (Z), a total of 12 months samplings were conducted between December 2012 and November 2013 in the south-east Black Sea. The overall sex ratio of females: males skewed towards males (χ2, P < 0.01). The SVBGF parameters, computed from monthly length frequency distribution analysis (LFDA), were estimated as L∞ = 8.25 cm total length (TL), K = 0. 549 year-1 for females and as L∞ = 8.44 cm TL, K = 0.490 year-1 for males. The seasonal oscillation in growth rate for females (C = 0.340) was larger than it was for males (C = 0.260). The slowest period of growth corresponded to December both females and males. The seasonal growth of the scaldback was most probably initiated by photoperiod and accelerated with decreasing water temperatures. Total instantaneous mortality rate, Z, was estimated as 0.853 yr-1 for females and 0.774 yr-1 for males. Instantaneous natural mortality ratio, M, was estimated a bit higher for females (M = 0.714±0.129) than for males (M = 0.655±0.098). The exploitation rate, E, of both sexes was also lower than the optimum exploitation (E = 0.5) criterion, which is indicative of non-exploited and/or lightly exploited of A. kessleri population. The results of this study were offered as biological input parameters for management of Black Sea stocks of the scaldback species.
  • Biometric indices of Pseudotolithus elongatus (Bowdich, 1825) from the coastal waters of Rivers State, Nigeria

    Dienye, Henry Eyina; Olopade, Olaniyi Alaba; Philip, Rejoice Upadi; Aiyeloja, Joy Osaretimi; Department of Fisheries, Faculty of Agriculture University of Port Harcourt, Nigeria (2023-12-26)
    Pakistan Journal of Marine Sciences
    Length-weight relationships (LWRs), length-length relationships (LLRs), and condition factor of Pseudotolithus elongatus from the coastal waters of Rivers State, Nigeria, were studied. Specimens were collected from the catches of fishermen using various fishing gear. The dominant length ranged from 20 to 26 cm, with a mean length of 22.65±3.06cm. The monthly length-weight relationship was estimated separately for male and female, with the b values indicating positive allometric growth (b > 3.00) in November, January, and February for both male and female. The females experienced negative allometric growth (b < 3.00) in December, March, and April, while the males exhibited a negative allometric growth pattern in April. The combined b value of LWRs (TL vs. BW) indicates positive allometric growth, and SL vs. BW indicates negative allometric growth. Also, the b value of LLR (TL vs. SL) indicates negative allometric growth. The condition factors varied for both sexes, ranging from 0.35 to 1.2 in males and 0.57 to 1.14 in females, while the combined condition factor ranged from 0.35 to 1.2. The present findings will provide useful information for a well-organized and significant exploitation and regulation of Sciaenid species following the aftermath of massive fish kills and continuous exploitation of fish species in the study area.
  • A review of aquatic toxicology investigations in Turkish waters.

    Bat, Levent; Hasançavuşoğlu, Zeynep; Öztekin, Ayşah (2023-06-30)
    Pakistan Journal of Marine Sciences
    Aquatic toxicity studies have been conducted for many years, and their importance has been understood for some time. The need for aquatic toxicity studies arises from the widespread use of chemicals in many different industries, such as agriculture, manufacturing, and energy production. These chemicals can enter aquatic environments through various means, including runoff from fields, discharges from factories, and spills or leaks from storage tanks or pipelines. Once in the aquatic environment, these chemicals can have harmful effects on aquatic life, including fish, crustaceans, molluscs, and algae. By conducting aquatic toxicity studies, researchers can gain a better understanding of the potential harmful effects of chemicals on aquatic life and ecosystems and can inform decisions about their use and regulation to protect the environment. This review summarizes the available aquatic toxicity studies in Turkish waters.
  • Metal causing DNA damage in lion fish Pterois miles from the northeastern Mediterranean.

    Ergenler, Ayşegül; Turan, Funda (2023-06-30)
    Pakistan Journal of Marine Sciences
    The influence of trace metal contamination on marine ecosystems and marine waters is a complex construct. Metal concentrations can cause carcinogenic and toxicogenic harm in marine environments. With a variety of sizes, ages, and trophic levels, fish are excellent markers of pollution from heavy metals for the identification of genotoxic factors in freshwater as well as marine systems. The current study used the damage frequency (%), arbitrary unit (%), and genetic damage index (%) in the gill and liver cells of P. miles to assess DNA damage brought along by toxic metals. Under the constant levels criteria used in this investigation, the levels of Cr, Hg, Fe, and Zn in the surrounding water are only slightly above the tolerance level. According to our findings, the frequency of damage in the lionfish's gill and liver cells was 53.66 to 73.512% and 39.33 to 45.033%, accordingly. The gill tissue had a higher frequency of injury than the liver tissue. Furthermore, Pb, Hg, Cr, Co, Fe, Ni, and Cu contents in seawater were shown to have a positive correlation with DNA damage levels in P. miles. As a result, our study revealed the first time genotoxic damage resulting from metal contamination in P. miles.
  • Characterization of long-spined sea urchin Diadema setosum shell and potential usage areas.

    Doğdu, Servet Ahmet; Turan, Cemal; Depci, Tolga; Bahçeci, Ersin; Turan, Funda (2023-06-30)
    Pakistan Journal of Marine Sciences
    The long-spined sea urchin Diadema setosum (Leske, 1778) is the most common seashore sea urchin in the tropical Indo-Pacific and also this species is distributed in the eastern Mediterranean Sea. In this study, we characterize the shell of the long-spined sea urchin Diadema setosum using FTIR and XRD analyses. The powdered shell of D. setosum was analyzed by Fourier transform infrared spectrometry. It was determined that 714 cm-1 and 871 cm-1 peaks from the formed peaks determined the amorphous and crystal structure, respectively. The results of the XRD analysis of the long spiny sea urchin shell overlap 91% with calcite with chemical formula Ca5MgC6O18 and 9% with periclase chemical formula Mg4O4. Analysis results show that D. setosum shell was found to be in calcite structure, and can be used in many areas such as paper, paint, plastic, construction, food, ceramics, and pharmaceuticals. When combined with other studies as antibacterial, anti-inflammatory, antimicrobial, and antioxidant, it has been revealed to contain amorphous and crystal structures that are useful for different biomedical industries. High availability and accessibility of the long-spined sea urchin, can become a very economical product for these sectors, and in this way, an invasive species will be brought into the economy.
  • Elemental accumulation in macroalgae Treptacantha barbata (Stackhouse) Orellana & Sansón, 2019 from Sinop, Türkiye.

    Arıcı, Elif (2023-06-30)
    Pakistan Journal of Marine Sciences
    In this study, the contamination profile of heavy metal levels (Cd, Cu, Fe, Hg, Pb, Zn) of Treptacantha barbata (Stackhouse) Orellana & Sansón, 2019, seawater and sediment samples were analyzed by ICP-MS and reference materials were used to determine the reliability of the analysis. All samples were collected from the Sinop coast (Türkiye) from August 2021 through April 2022. As a result of the study, metal levels were found in the following sequence: Hg < Cd < Pb < Cu < Zn < Fe for seawater and T. barbata and Hg < Cd < Cu < Pb < Zn < Fe for sediment. Among the metals, Cu was bio-accumulative in biota; Cd and Hg metals in the sediment are micro concentrator by T. barbata.
  • Brine shrimp provides a rich-high energy food for migrating birds: A case study of an artificial pond in Basrah, Iraq.

    Ali, Malik Hassan; Mohammed, Hanaa Hussein; Abdulla, Dawood Salman; Ahmed, Huda Kadhim (2023-06-30)
    Pakistan Journal of Marine Sciences
    A case study focusing on the attraction of migrating birds by brine shrimp (Artemia franciscana) into an artificial pond in Basrah, Iraq. A dump area had constructed at the intertidal mudflat’s zone of Khor Al-Zubair Channel, Basrah, Iraq. Basra Gas Company implemented a dredging operation to increase the channel depth in 2019 to use the dump area as a disposal place for the company’s benthic sediments, which are usually mixed with seawater, converting the dump area to a large hypersaline artificial pond. Unexpectedly, the pond became a habitat for many shorebird species a few months later. The pond has been surveyed five times between March 2019 and January 2020. For each survey, frequent environmental and biological events were observed. Due to high temperature during most summer months (30-50°C), the water level decreased dramatically to (< 0.5 m), which ultimately led to increase levels of salinity in the pond (80 psu). Moreover, growth of blue-green algae was observed and appearance of brine shrimp A. franciscana. During autumn and winter surveys, an abundance of live A. franciscana and their cysts was observed. Birds appeared to forage primarily on A. franciscana in the pond. The abundance of brine shrimp attracts migrating birds to exploit this prey. 11 species of migrating birds were detected in the pond. These species were flamingo Phoenicopterus ruber, flocks of avocet Ricurvirosta avosetta and Shelduck Tadorna tadorna. Therefore, this site with abundant food resources could provide a rich-high energy food for migrating birds and staging area for a long flight.
  • Studies on the morpho taxonomic variations of four Centropagidae species (Crustacea: ‎Calanoida) with note on their abundance collected from Sonmiani Bay, northern ‎Arabian sea

    Mubarak, Shumaila; Ali, Qadeer Mohammad (2022-12-31)
    Pakistan Journal of Marine Sciences
    Centropagidae is comparatively a larger family to other families of order calanoida. The ‎quantitative data revealed that the copepods of the genus Centropages are the ‎dominant component in the zooplankton samples from the designated station in ‎Sonmiani bay, a coastal lagoon at Balochistan coast, northern Arabian sea. Four ‎epipelagic species of family Centropagidae, Centropages (Centropages dorsispinatus ‎Thompson I.C. & Scott A., 1903, Centropages tenuiremis Thompson I.C. & Scott A., ‎‎1903, Centropages furcatus (Dana, 1849) and Centropages orsinii Giesbrecht, 1889 ) ‎were identified. Male and female specimens were distinguished on their characteristic ‎features of antennules, thoracic segments and fifth legs. Identified specimens were ‎described briefly with their microscopic illustrations. Centropages dorsispinatus and ‎Centropages tenuiremis were frequently found in zooplankton samples throughout the ‎sampling season.‎
  • Morphometric relationship of Perna viridis Linnaeus, (1758) from the Manora Channel, ‎coastal waters of Pakistan

    Naz, Farah; Afsar‎, Nuzhat; Abbas‎, Ambareen; Siddiqui, Hafsa Hoor; Diljan, Salman; Sherazi, Syed Ibtehaj (2022-12-31)
    Pakistan Journal of Marine Sciences
    Perna viridis (Green Mussels) is characterized by fast-growing, found in large clusters, ‎one of the dominant bio-fouling organisms, native to West Indo Pacific region and ‎commonly distributed along the Southeast Indian and Asian coast. They are found in ‎the shallow sublittoral water up to a depth of 15 m and be able to tolerate an extensive ‎range of environmental situation i.e. tolerate temperatures range of 15-32.5C. Green ‎mussels were collected from the navigation buoy in Manora Channel and brought to the ‎research laboratory. Samples were washed to remove the sand, vegetation, and other ‎particles. Morphometric measurements were measured to the nearest gram. The result ‎revealed that the shell length ranged between 0.60-7.4 cm, the width range between 0.10-‎‎2.9 cm, and the weight range between 0.037-15.549 g. In all morphometric relationships, ‎the validation of the “b” values was significantly different from the isometric value. ‎Significant correlation variation was observed in all variables whereas the highest ‎correlation values were observed in the length-width (n-224, r2 = 0.966) and the lowest ‎was observed in width-total weight (n-224, r2 = 0.85). The analysis of variance (ANOVA) ‎revealed that all variables showed significantly different (DF=1, p<0.000).‎
  • Estimation of population structure, growth and condition of Lates calcarifer (Bloch, ‎‎1790) in the Bay of ‎Bengal

    Ilah‎, Nur-E-Farjana; Abedin‎, Md. Joynal; Rahman‎, Md. Ashekur; Azad‎, Md. Abul Kalam; Khatun‎, Most. Taslima; Asadujjaman‎, Md.; Samad, Md. Abdus; Habib, Kazi Ahsan; Ali, Md. Nowsher; Sarmin, Most. Shakila (2022-12-31)
    Pakistan Journal of Marine Sciences
    The current study illustrates the life-history traits; including length frequency distribution ‎‎(LFD), length-weight and length-length relationship (LWR and LLR), condition factors ‎‎(allometric, KA; Fulton’s, KF; relative condition, KR; relative weight, WR), and natural ‎mortality (Mw) of Lates calcarifer from the Bay of Bengal, Bangladesh. A total of 103 ‎individuals were randomly collected from January to December 2021 using traditional ‎fishing gear including Koral net and gill net. For each individual, total length (TL), ‎standard length (SL), and total body weight (BW) were measured with measuring scale to ‎‎0.1 cm and digital balance to 0.1 g precision, respectively. The TL size class 84.0 cm was ‎a numerically dominant group in the population. The b value of LWR (TL vs. BW) ‎indicated positive allometric growth (b=3.28) pattern in the Bay of Bengal. Likewise, the ‎b value of LLR indicated also the same growth pattern. Among the four types of ‎condition factors, KF is the best-suited tool for evaluating the well-being of L. calcarifer. ‎Additionally, WR exhibited significant divergence from 100 (P< 0.0001), defining an ‎imbalanced habitat. The calculated Mw was 0.23 year-1 for L. calcarifer. Therefore, these ‎findings would be used in the future for the improved management of this species in the ‎Bay of Bengal as well as for connecting ecosystems.‎
  • A new species of Philometra reported from the ovaries of edible fish Epinephelus ‎bleekeri (Vaillant, 1878) of the Karachi coast

    Rizwana, A.G.; Zulfiqar, Sumbul (2022-12-31)
    Pakistan Journal of Marine Sciences
    Nutritionally, fish meat is identified as healthiest meat all over the world. Nutriments that ‎are essential for healthy diet can be easily drive from fishes. Beside fish meat there are ‎various type of derivatives that we can obtain from them. Economically fish industry is ‎considered as backbone for any country. Approximately, 45,000 species of helminth ‎parasites cause pathogenicity in vertebrate hosts that are known to man. Parasite that ‎belong to family Philometridae usually invade different body organs and cavities of ‎various fishes. Parasite that cause pathogenicity in reproductive organs of fish ultimately ‎cause disturbance in their release of reproductive hormones, mating behavior, difficulty ‎in spawning and ultimately number of fry production is declined.‎ This research was conducted on the nematode parasites of marine fish Epinephelus ‎bleekeri (Vaillant 1878) from Karachi coast during January,2021 to December,2021. In ‎this one year research, a new species of nematode Philometra bleekerii n.sp. was ‎recorded from the reproductive organs of marine fish Epinephelus bleekeri (Vaillant ‎‎1878).‎
  • Effect of freezing period on chemical composition, microbial load and some pathogenic ‎bacteria of Nile tilapia (Oreochromis niloticus)‎

    Yagoub, Hassan M. (2022-12-31)
    Pakistan Journal of Marine Sciences
    This study evaluated the effects of freezing periods on nutritional values, microbial ‎loads, and some pathogenic bacteria in Nile Tilapia (Oreochromis niloticus). 8 kg.‎‏ ‏Samples were collected from El-mawourda Fish Market in Khartoum State, for four ‎experimental treatments. The treatments were conducted on the period 0 day, 7 days, 15 ‎days and 21 days.‎‏ ‏It is noticed that the freezing period effect on the nutritional value, ‎microbial load and some pathogenic bacteria of Nile tilapia (Oreochromis niloticus) ‎revealed that the lowest average nutritional assessment of Nile tilapia (Oreochromis ‎niloticus) observed for protein 20% at the third period of freezing (21 days), and ‎minerals were calcium, phosphorus, magnesium, iron, sodium and potassium (5.6 – ‎‎2.7%, 4.8 – 2.9%, 2.6 – 2.9%, 1.1 – 0.71%, 4.5 – 2.8%) respectively. The‏ ‏result of this ‎study clarified that the freezing period has a considerable consequence (p ≤ 0.05) on the ‎chemical composition, microbial load and same pathogenic bacteria (E. coli and ‎Salmonella) of Nile tilapia (Oreochromis niloticus).‎
  • Modelling current and future distribution of the invasive silver-cheeked toadfish ‎Lagocephalus sceleratus in the Mediterranean Sea

    Turan, Cemal; Doğdu, Servet Ahmet (2022-12-31)
    Pakistan Journal of Marine Sciences
    The progress in species distribution modeling has brought new insights into biological ‎invasion management. The present study aims to model the potential current geographic ‎distribution and future expansion of silver-cheeked toadfish Lagocephalus sceleratus in ‎the Mediterranean Sea. Coordinates of 98 occurrence records of L. sceleratus in the ‎Mediterranean were used, and marine climatic variables were collected from the global ‎databases. Fifteen modeling techniques were tested, and weighted ensemble averaging of ‎the model replicates was built. AUC values for each model ranged from 0.61 for rpart to ‎‎0.99 for rf, and TSS values varied from 0.41 for mlp to 0.95 for rf. Based on the cutoff ‎values of TSS and AUC, the seven modelling algorithms were used for ensemble ‎modeling. The maximum seawater temperature at minimum depth explained strong ‎biological importance to the current adaptation, and the salinity contributed the most to ‎the future adaptation. The ensemble forecasting of suitable habitats of L. sceleratus for ‎current distribution modeling revealed that L. sceleratus dominantly occurred in ‎the middle and eastern parts of coastal areas of the Mediterranean. The future ‎distribution was extended to the western part of coastal areas of the Mediterranean, ‎classifying the high suitability of these areas for its future distribution. The suitable ‎bioclimatic envelope of L. sceleratus under the present study is predicted to widen ‎because of climate change. The likely regions of invasion and the areas at risk for a ‎potential future invasion of L. sceleratus indicate that prompt, effective practical actions ‎by resource managers should be undertaken to mitigate its impacts and spread.‎
  • Considerations on the low-altitude operations of the cruising-type AUV Gondou for seafloor photographic surveys.

    Nagasawa, Ryosuke; Tanaka, Kitoshi; Horinouchi, Ryoichi (2023)
    Report of Hydrographic and Oceanographic Researches
    The Japan Coast Guard AUV Gondou is a cruising-type autonomous underwater vehicle. The Gondou is equipped with a downward-looking camera system that potentially unveils detailed seafloor feature from a different perspective than acoustic observations. As the Gondou is designed to run at relatively high-speed for wide-range seafloor mapping, the vehicle has limited maneuverability in horizontal and vertical directions. These operational characteristics of the vehicle require careful considerations in the design of mission planning and predetermination of contingency avoiding behaviors. This technical report notes our operational efforts to conduct seafloor photographic surveys with the cruising-type AUV.