Thalassas: An International Journal of Marine Sciences最新文献

Thin plastic films used for packing food materials are unsafe for consumers and are not readily degradable. Single-use plastic films accumulate in the environment and cause adverse effects in the food chain. In this study, Kappaphycus alvarezii, which has the value-added polymer carrageenan, was used for developing a bioplastic film along with the plasticizer polyethylene glycol (PEG 3000). Different concentrations of seaweed were used (3%, 4% and 5% dry weight), of which 4% had a higher tensile strength than the other concentrations. The physical and mechanical properties of the developed plastic films, such as thickness, tensile strength (TS), water vapor transmission rate (WVTR), oxygen transmission rate (OTR) and color, were tested for packaging applications in the food industry. A higher concentration of seaweed increased the WVTR, and a lower concentration increased the OTR. In addition, the biodegradation of the developed bioplastic was tested using isolated deep-sea microbial consortia to meet environmental standards. A deep-sea marine microbial consortium (Bacillus paralicheniformis G1, Bacillus subtilis G2, Bacillus subtilis Z1, and Enterobacter cloacae subsp. dissolvens Z2) degrades seaweed (Kappaphycus alvarezii)-derived bioplastic under buried soil conditions. The maximum degradation (88%) in the 5% (w/v) bioplastic film was observed within 10 days of incubation.

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This study focuses on the mineral content and health risk assessment of the brown seaweed Colpomenia sinuosa. The mineral composition of the seaweed samples (Na, K, Mg, Fe, Cu, Zn, Mn, P, Ni, Pb, Cd, Cr, Al) was investigated from three different Turkish coastal locations: İzmir Bay (S1), the Strait of Çanakkale (S2), and the Sea of Marmara (S3). The mineral contents of samples were analyzed using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) as part of our methodology. It was found that the mineral content varied significantly depending on the location from which the samples were taken. The highest levels of Na, Ca, Mg, Fe, Ni, and Mn were observed in the samples from İzmir Bay, whereas those from the Sea of Marmara showed elevated levels of P and Zn. The study also revealed the presence of heavy metals, including Pb, Co, Cd, Cr, and Al, in the seaweed. According to hazard index (HI) calculations, adult consumption of this seaweed poses a low health risk, with a hazard index below 1. Various heavy metals have been detected in the seaweed, but their concentrations are not high enough to pose significant health risks, and therefore, the seaweed is safe for human consumption within reasonable limits. Our results suggest that C. sinuosa could be a valuable source of essential minerals for human consumption.

The Japanese velvet dogfish Scymnodon ichiharai Yano and Tanaka 1984 (Somniosidae) is a rare deep-sea shark hitherto known only from the northwest Pacific Ocean. This species is observed for the first time from the northern Indian Ocean. Two male specimens with total length (TL) of 760 mm, and 323 mm were caught by longline hook in the commercial motorized longline boat fishery at a depth of 400 m off Port Blair, Andaman Islands, India. We provide morphological descriptions of S. ichiharai from India in comparison with formerly identified specimens along with DNA barcodes from this region. The capture of this species in the northern Indian Ocean is a considerable biogeographic range extension and confirms the first record of S. ichiharai from the Indian EEZ.

This manuscript presents a detailed investigation into the stock status of Thenus unimaculatus, a commercially valuable lobster species in India. In data-poor fisheries, Bayesian approach offers robust guidance for sustainable sand lobster population management. Utilizing a non-conventional Bayesian approach, the study employed length-based Bayesian biomass (LBB) and length-based Spawning Potential Ratio (LB-SPR) methods to analyze length frequency data collected between 2011 and 2019. In our study using LBB, the current exploited biomass (B/B0 = 0.35) was found to be lower than the biomass capable of producing maximum sustainable yield (B/B_MSY=0.93). Spawning potential ratio was calculated between 28 and 37% using LB-SPR model. The fishing mortality (F/M = 1.5) was slightly above optimal, resulting in low sand lobster biomass due to moderate over-exploitation. This suggests a need for rational slipper lobster catch control. However, with an L_m50/L_c50 ratio close to 1.0, indicates an absence of targeted juvenile fishery, it suggest the need to reduce fishing pressure. . However, implementing measures is challenging because the species forms a by-catch in trawl fisheries.

Under controlled laboratory conditions the Cd effects on hemolymph superoxide dismutase (SOD) activity were evaluated at 8.8, 24.9 and 249 µg Cd/L and exposure times of 5, 48, and 96 h. Shrimp hemolymph samples were extracted from the first abdominal segment and hemocytes separated by centrifugation, and SOD activity (units/mg of protein in shrimp hemolymph) was quantified using the RANSOD assay kit. No mortality was observed in the controls and treatments. Superoxide dismutase activity ranged from 0.938 ± 0.0938 to 0.946 ± 0.042 SOD units/mg of protein in shrimp hemolymph in controls. At 5-h exposure, SOD activity decreased at all Cd concentrations, with significant differences (p < 0.05) than those of controls. However, a significant (p < 0.05) SOD activity increase was observed at 48-h exposure in those shrimp exposed to 24.9 and 249 µg Cd/L; but a significant (p < 0.05) SOD decrease was determined in those specimens exposed to highest Cd levels at 96-h exposure. More experiments such as those in this study are required for future updates of protection criteria for Cd in estuarine and marine environments.

Angelfish (Pomacanthidae) are fish distributed in reef areas in the tropical and semi-tropical regions of the Atlantic and Indo-Pacific oceans. Up to now, five different species of this particular species have been identified in the Mediterranean, but there are suspicions that one of them is misidentified. The Emperor angelfish (Pomacanthus imperator) is the most frequently reported species from the Pomacanthidae family in the Mediterranean region. This study presents a new record (36°44’34.59"N, 31°24’6.42"E) of the Emperor Angelfish from the Antalya Gulf in the Mediterranean. The recent sighting of P. imperator in the Gulf of Antalya marks its eighth location in the Mediterranean, its second on the Turkish coast, and its first in the Gulf of Antalya. Following this research, the count of fish species originating from the Red Sea found in Antalya Bay has now reached 71. When the location records of this fish in the Mediterranean are examined, it is seen that it has expanded its distribution towards the west.

A female albino fanray specimen was collected by trawl from the southern Taiwan Strait on April 11, 2022. This unique individual was identified as the Chinese fanray, Platyrhina sinensis (Bloch & Schneider, 1801), based on morphological identification and DNA barcoding. It was classified as partial albinism (leucism) due to the absence of pigmentation in the skin and normal pigmentation in the irises. This specimen represents the first reported case of albinism within the family Platyrhinidae, providing valuable insights for physiological and ecological research on albino fish.

Kuala Terengganu, one of the coastal zones in Malaysia, is prone to natural hazard factors, such as coastal erosion which may affect the morphological condition of the beaches in Terengganu. The beach morphological changes were driven by the seasonal monsoon such as Northeast Monsoon (NEM) and Southwest Monsoon (SWM). Hence, to understand the short-temporal morphological response of meso-tidal beaches during spring tide events throughout the lunar cycle phase, the study was investigated in Batu Buruk Beach, Kuala Terengganu. The coastal profiles, particularly during spring tide (Full Moon and New Moon phases) were collected from five (5) transects starting on October 2020 to October 2021. The monitoring of cross-shore was conducted using Real time Kinematic (RTK) to measure the cross-sectional area and sediment volume changes. The data collected were computed using profiler 3.2XL software. MIKE-21 numerical modeling software was used to simulate tidal elevation within the period of this study. The results showed that Batu Buruk Beach received significant impact from the lunar cycle, especially on sediment gain and loss. The cross-sectional analysis revealed positive sediment gains during the Full Moon. However, during the New Moon phase, erosion seemed to take place around the upper swash zone area. This provides an insight into the spring tide erosion and accretion and contributes some understanding to beach recovery processes.

A free-swimming longtail butterfly ray, Gymnura poecilura (Shaw, 1804), specimen with significant abnormality was observed from the Bay of Bengal along the Odisha coast, east coast of India. One specimen, collected from Arjyapalli fish landing Centre along the Sothern Odisha coast, has the pectoral fins on both sides evenly split or symmetrically bifurcated for which initially the identity of the specimen was confusing. When classical taxonomy could not resolve the confusion, molecular analysis helped in obtaining species identity, which was confirmed as Gymnura poecilura. Pectoral fin splitting abnormality in the Gymnuridae family is reported herewith for the first time.