Breviturma pusilla is redescribed and illustrated based on two specimens collected from the remote oceanic island of Trindade (Brazil). The species is distinguished from its congeners primarily by the presence of fragile, hollow and microscopically thorny arm spines. This constitutes the first record of the genus Breviturma and B. pusilla from the southwestern Atlantic Ocean. A key to the species of Breviturma is also provided. The present record of B. pusilla from Trindade is consistent with the Indo-Pacific component of the island fauna.
Current projections of climate change indicate potential impacts on coastal ecosystems, including rising seawater temperatures, which may directly affect endemic and ecologically important species such as the mangrove crab Ucides cordatus. This study aimed to assess the physiological impacts of climate-induced heat stress in this species, using cytological (NRRT, neutral red retention time) and oxidative stress (LPO, lipid peroxidation) biomarkers across multiple tissues. Crabs were collected from mangroves in Canan & eacute;ia, SP, Brazil, and subjected to controlled thermal exposure under two regimes: control (24 +/- 1 degrees C) and treatment (30 +/- 1 degrees C), based on IPCC climate projections. Two experimental durations were tested: acute (12 -36 hours) and chronic (2 -7 days). Crab cells exhibited reduced NRRT in both trials, although no statistically significant differences were observed between thermal groups. Animals exposed to heat stress showed consistently lower NRRT values, suggesting sublethal physiological disruption. Significant differences in LPO levels were detected only during acute exposures and varied by tissue type. These findings provide novel physiological evidence of thermal sensitivity in U. cordatus, reinforcing its potential as a bioindicator of ecological vulnerability and its application in integrated monitoring frameworks for mangrove conservation under climate change.
This study assessed the population parameters of Canthidermis maculata off the southern coast of Sri Lanka and quantified the waste generated during its processing into dried fish, with particular emphasis on the valorization potential of skin waste. Catch data, morphometric measurements, and processing waste information were collected through fortnightly field visits to the Negombo dried fish processing site from May 2023 to April 2024. Population parameters were estimated using the TropFishR package. Skin waste was converted into fish leather using vegetable tanning agents (tea leaf and Indian almond leaf extracts) at 25%, 50%, and 100% concentrations, and chromium sulfate (Cr-2(SO4)(3)), employing single and dual tanning methods. Canthidermis maculata exhibited negative allometric growth (b = 2.32). Growth and mortality parameters were estimated as L infinity = 52.2 cm, K = 0.536 yr(-)& sup1;, Z = 3.605 yr(-)& sup1;, M = 0.709 yr(-)& sup1;, and F = 2.897 yr(-)& sup1;. The current exploitation rate (E-curr = 0.80) exceeded the maximum sustainable level (E-max = 0.42), indicating overexploitation. Processing generated similar to 35% waste, including 10% skin waste. Fish skin treated with 100% Indian almond leaf extract using the dual tanning method produced the highest quality fish leather. These findings update knowledge on C. maculata fisheries and highlight opportunities for fish waste valorization.
This study examined the capture dynamics of mantis shrimp (Squilla mantis) in the small-scale fisheries of Thermaikos Gulf (N. Aegean, Greece) by using commercial catch data and video recordings during net hauling. Mantis shrimp was a major bycatch species in the trammel-net fishery targeting the common sole Solea solea, accounting for 11% of total biomass. Notably, 54.9% of mantis shrimp catches were commercialized, 42.1% were retained by fishermen and only 2.2% discarded, primarily owing to damaged individuals. Their abundance was strongly associated with to muddy substrates and positively correlated with teleost fishes, particularly flatfishes like common sole and spotted flounder Citharus linguatula. Observations provided direct evidence of mantis shrimp actively preying on fish trapped in nets, with nearly one out of every five mantis shrimp preying on different species and establishing predatory groups of 2-11 individuals per prey item. Mantis shrimp occurred both individually and in clusters, the latter usually linked to feeding activity. The reported dual role of mantis shrimp as a large local economic asset and an active predator of valuable commercial flatfish within nets should aid in fisheries management, market exploitation and ecological knowledge of this important benthic predator.
A new species of dromiid crab Cryptodromia colini n. sp. is described based on a male specimen collected from Shivrajpur village, Saurashtra coast, Gujarat State, India. The morphological characters of C. colini n. sp. are described and figured, and compared with allied taxa. The taxonomy of the related C. coronata Stimpson, 1858 the type species of the genus, is also discussed. This poorly known species is redescribed and figured in detail. With the description of the new taxon, seven species of Cryptodromia are now known from India.
Intermittently open/closed estuaries are dynamic ecosystems that undergo shifts in hydrological connectivity, with significant implications for estuarine biodiversity. This study investigated how estuary mouth state (open vs closed) influences benthic macrofaunal community structure associated with seagrass Zostera capensis in the Swartvlei Estuary, South Africa. Sampling was conducted during both mouth phases, and metrics including species richness, Shannon diversity, Pielou's evenness, Lloyd's patchiness, and the AED index were calculated. Analyses revealed significant shifts in macrofaunal assemblages between mouth states, with higher abundance and richness observed during the open phase. Despite lower richness during closure, evenness was higher, indicating a more balanced community. Patchiness was elevated, suggesting fine-scale environmental heterogeneity. Dominance of taxa such as Davisassiminea capensis and Davishydrobia knysnaensis reflected tolerance to low oxygen and low salinity conditions. Comparative analysis with Knysna and Keurbooms Estuaries showed that Swartvlei macrofaunal metrics during the open phase approached or exceeded those of more marine-influenced systems, highlighting the importance of temporal variability in assessing estuarine biodiversity. These findings underscore the sensitivity of benthic communities to mouth dynamics and support adaptive estuarine monitoring frameworks that integrate biodiversity indicators with hydrological variability. Understanding these dynamics is essential to the conservation of intermittently open- and closed-estuaries and their associated habitats.
The Arabella iricolor species complex (Annelida: Oenonidae), inhabiting intertidal rocky shores worldwide, has been regarded as carnivorous; however, a taxonomic revision based on morphological and molecular evidence is required, and its feeding behaviour has not been documented in detail. Here, we report the nocturnal feeding behaviour of Arabella in Japan. Morphologically, it clearly differs from A. iricolor and is regarded as the same species as Arabella cf. iricolor from Korea. Furthermore, phylogenetic analysis based on mitochondrial COI gene sequences indicates that it is phylogenetically distant from A. iricolor from around the type locality. Although actual feeding was not observed during our survey, eight species belonging to Arthropoda, Mollusca, and Annelida were found enclosed within the mucus produced by Arabella cf. iricolor. Among them, the limpet Cellana toreuma (Patellogastropoda: Nacellidae) and the false limpet Siphonaria sirius (Heterobranchia: Siphonariidae) were covered with mucus secreted by Arabella cf. iricolor and their soft bodies were almost completely consumed by the worms. Given the wide geographic distribution of the A. iricolor species complex and its occasional abundance on rocky shores, predatory behaviour by Arabella represents a previously overlooked component of rocky shore food webs.
Marine biodiversity provides vital ecosystem services but faces multiple threats, leading to global declines and increasing concern. Effective conservation of marine biodiversity requires comprehensive knowledge of species and accurate taxonomic identification, which remain challenging. DNA barcoding offers a reliable method for species identification. Focusing on the Southern Atlantic Moroccan ecosystem, this study aims to link DNA barcodes to species, investigate cryptic diversity and provide an updated marine species checklist. A total of 145 specimens from 85 species were collected and barcoded, producing 72 unique BINs in BOLD. Most sequences exhibited over 97.8% similarity with existing data, while nine sequences formed three new BINs. Twenty-three species displayed 2-12 BINs, indicating potential cryptic diversity or misidentifications. Additionally, sequences were used for Discriminant Analysis of Principal Components and Neighbor-joining analyses, thereby improving understanding of species boundaries. A morphological reassessment of the specimens was performed when discordances between BIN assignments and species names were observed. This study contributed to updating Morocco's marine checklist, demonstrated high success in species-level discrimination by combining genetic and morphological reassessments, and revealed potential cryptic diversity that warrants further investigation. Continued research is essential to monitor and conserve the Moroccan marine biodiversity amid global environmental changes.
This study examined the population genetic structure, connectivity, and demographic history of the mangrove snail, Terebralia palustris, along the coast of Tanzania through mitochondrial COI sequence analysis. Samples were collected from Tanga, Dar es Salaam, Mtwara, Mafia, Pemba, and Unguja. The extraction of genomic DNA was done from muscle tissue using CTAB method and the COI gene was amplified by PCR amplification with the LCO1490 and HCO2198 primer pair. Subsequent analyses of the COI sequences revealed a moderate haplotype diversity and a low nucleotide diversity. Although Tajima's D and Fu's Fs, were negative but non-significant (p > 0.05), a unimodal mismatch distribution and star-like haplotype network provided stronger evidence for recent demographic expansion in the population of T. palustris. Moderate genetic differentiation among populations was revealed by F-ST value, indicating substantial gene flow and the likelihood of a single panmictic population. The absence of significant genetic structure supports treating the T. palustris fishery along the Tanzanian coast as a single unit stock. Maintaining habitat quality remains important because healthy, connected habitats facilitate gene flow among sites, helping sustain genetic variation and enhancing the species' long-term resilience.
As humans alter marine environments, building infrastructure that also provides habitat benefits helps counterbalance negative impacts. Little is known about whether built environments can provide useful habitat below the photic zone. We describe fouling assemblages developed after two and ten years on settling plates near a wastewater pipe at three depths, ranging from 30- to 183-m deep, in Puget Sound, Washington. The outfall pipe and plates of the same material provided islands of hard substrate in a silt-dominated habitat. Analyses of 24 plates across depths and times showed substantial consistency in the assemblages; these were already diverse after two years, although biotic cover increased with time, with some shift from short-lived bryozoans to longer-lived bivalves and anemones. Virtually all differences among depths and times were a matter of relative abundances. Plates deployed near the pipe's diffuser showed no effect of exposure to treated effluent relative to plates deployed 90 m away. The results suggest that larval supply and food resources do not limit species below the photic zone in Puget Sound. Infrastructure that introduces a hard substrate at depth can provide habitat for suspension feeders when oceanographic conditions support the advection of larvae and organic matter needed to sustain benthic communities.
The complexity and opacity of biological data in fisheries makes the deep application of artificial intelligence in marine fishery management challenging. Moreover, establishing a reliable model for fish identification is vital for the management of fishery biological data, and interpretable methods enable us to deeply understand the decision-making mechanism of such models. This study selected Thunnus albacares as the research target and constructed an image classification framework based on the VGG16 model. Advanced techniques such as feature map visualization were used to analyze the decision-making mechanism of this model. The experimental data included standard samples, challenging samples, and samples obtained under various noisy conditions. This study revealed the hierarchical fusion process of the model, indicating that the key decision-making areas of the model highly coincide with the identification marks used in traditional biology. The results of this study will provide a solid foundation for improving related models and strongly promote the in-depth development of artificial intelligence in the fields of fishery biology and fishery management.
This study investigated aspects of the reproductive biology of Alpheus carlae Anker, 2012 by evaluating fecundity, reproductive output, and embryo volume in females from a highly disturbed environment. Sampling was carried out in two periods: June, August, and November 2021, and bimonthly from March 2024 to January 2025, in a mangrove remnant at Ara & ccedil;& aacute; Bay, S & atilde;o Sebasti & atilde;o, S & atilde;o Paulo, Brazil. The mean fecundity of females with embryos at the initial development stage (I) was 801 +/- 593 (mean +/- SD), ranging from 10 to 1,890 embryos, and it showed a positive correlation with female body size. The mean reproductive output was 7 +/- 5.41%. Embryo volume differed significantly among the development stages I, II, and III, showing increases of 23%, 48%, and 82%, respectively. These findings indicate that, despite inhabiting an anthropized habitat, females of A. carlae can maintain a high reproductive potential, which may be associated with the elevated levels of organic compounds derived from sewage contamination. Moreover, these results improve our understanding of how environmental conditions influence the reproductive strategies of caridean shrimps and provide valuable comparative insights for future studies in both anthropized and preserved ecosystems.
The present study examined how background colours influence the body colouration of Cuapetes purushothamani, a newly discovered palaemonid shrimp from Lakshadweep, India. Shrimps were placed in tanks with black, blue, green, and white backgrounds (10 per colour, two replicates of 5 each) without substrate. Photographs were taken at the start and after 50 days to analyse colour changes using RGB values (Red, Green, Blue) from the cheliped, eye stalk, first abdominal somite, and telson via ImageJ software. Initially, RGB values varied due to different collection environments. After the experiment, black backgrounds significantly affected both sexes (p < 0.05), while blue influenced males but not females first abdominal somite. Telson colour differed between sexes in the green background (p < 0.05), while all parts except the female telson differed in the white background (p < 0.05). Shrimps darkened in black and blue tanks for camouflage, while white and green backgrounds led to the abdomen and telson brightening. These findings highlight C. purushothamani's ability to adjust colouration for survival, offering insights into its behavioural ecology, camouflage strategies, and applications in biodiversity conservation and aquaculture.
The paper documents the anatomy of specimens of the marine triclad Micropharynx parasitica found in experimental woodblocks at depths of similar to 1600 m from the NE Pacific and compares it to that of North Atlantic specimens of the species. North Atlantic specimens of M. parasitica are known only as ectoparasites of four species of skate, while the deep-sea population in the NE Pacific concerns free-living animals. Absence of eyes and body pigmentation in M. parasitica may be related to the deep-sea habitat instead of its association with skates. The fact that M. parasitica also occurs freely on the bottom of the ocean and apparently is able to survive without host species stimulated the authors to develop some hypotheses on the conundrum of its reproductive biology and its potential dispersal between such separate ocean basins. It may be the case that skates pick up free-living Micropharynx when the fishes deposit their egg cases on the sea floor and that the triclads deposit their cocoons on suitable substrates on the bottom of the ocean and do not attach the capsules onto their host species. Perhaps a species of skate functions for Micropharynx as a means of transport between the two ocean basins.
A new species of tubulanid palaeonemertean, Tubulanus kajiharai sp. nov., is described based on body coloration and patterns from Subarnarekha Estuary, the northeastern coast of the Bay of Bengal, India. The genus Tubulanus Renier 1804 currently comprises 33 valid species; T. kajiharai sp. nov. is easily differentiated from its congeners by the presence of a distinct white mid-dorsal longitudinal stripe and several epidermal constrictions on a pale green background. Maximum likelihood and Bayesian inference analyses, based on combined COI and 16S datasets, confirm the placement of Tubulanus kajiharai sp. nov. within Tubulanus and support its validity as a distinct species.
The complex hydrography and coastal geomorphology of the Magellan region in Chilean Patagonia support a highly diverse yet largely unexplored benthic community. Establishing a baseline is essential for detecting future ecological change and informing conservation strategies. This study examines the spatial distribution of subtidal benthic communities in the Strait of Magellan. Megabenthic invertebrates were characterized across five localities along a depth gradient (5, 10, 15 and 20 m) using underwater photoquadrats. A total of 64 species were identified. PERMANOVA revealed no significant differences in community composition across depth, although species richness increased with depth. In contrast, significant differences were detected among localities, with Bell Bay showing the most distinct assemblage, largely driven by Arossia henryae (SIMPER). The high abundance of sessile species, including A. henryae, Magellania venosa, Didemnum studeri, Errina antarctica and Psolus sp., highlights the role of suspension feeders as ecosystem engineers that enhance habitat complexity and biodiversity. Cape San Isidro exhibited reduced sessile cover and extensive bare substrate, likely associated with environmental constraints. No clear depth-related pattern was observed for vagile species. These results emphasize the need to conserve these vulnerable subtidal habitats..
In November 2023 and February 2024 juvenile specimens of the Zu cristatus (Bonelli, 1819) and Trachipterus trachypterus (Gmelin, 1789) were caught in the Strait of Sicily during two different bottom trawl surveys. The Z. cristatus specimen measured 420 mm in total length and 87.01 g in weight whereas the T. trachypterus measured 315 mm in total length and 15.64 g in weight. The present study constitutes the deepest record of Z. cristatus in the Strait of Sicily. In addition, an age estimation and an update on the geographical distribution of these Trachipteridae species in this region were also presented. Based on the growth increments of calcified structures (vertebrae), the estimated age was 3 years for the Z. cristatus specimen and 2 years for T. trachypterus. Rarely reported species often lack economic value, which may underestimate their abundance. Therefore, more studies and research surveys are necessary to fill the information gap on the biology of these deep-water species.
This publication comprises an autecological study of the scavenging amphipod Tmetonyx cicada (Fabricius, 1780), caught in baited traps in Osterfjorden on the west coast of Norway. The samplings were conducted in the period 1993-1996. Presumed influences of environmental factors on the bait attraction of the amphipod were investigated in field experiments. Depth and the degree of in situ illumination resulted in significant factors for T. cicada in terms of food search, showing preferences for deeper waters. Catches increased significantly with increasing amounts of bait, and catches were larger when the fish bait was cut into pieces than when using minced bait. The catch rates of T. cicada varied in an irregular pattern at the collection site, probably due to weak and variable currents at the trap site. A multiple-trap rig caught T. cicada from the seabed and up to 1.5 m above the seabed. Mean swimming speeds were measured in the laboratory, ranging from 4.0 cm/s for juveniles to 12.5 cm/s for adult females. The estimated average infaunal density of T. cicada from grab samples in pristine areas along the Norwegian coast was 6.6 specimen/m2.
Pigmentation patterns in marine polychaetes of the family Hesionidae hold significant diagnostic value but remain underutilized in taxonomic studies due to their loss during specimen preservation. These worms can display vivid colouration patterns, including red and brown hues, white spots, bands, and dark patches, that aid in species discrimination. However, such features often fade when specimens are stored in ethanol. This study evaluates the effects of different fixation techniques (i.e. ethanol PA, formaldehyde 4% and 37%) on the preservation of dorsal body pigmentation, eye colour, and the visibility of a posterior white glandular region. Specimens were examined across three regions: (i) general body pigmentation, (ii) eye pigmentation, and (iii) posterior gland visibility. Pigmentation was categorized as preserved, partially lost, or completely lost. Results indicate that body pigmentation was entirely lost across all treatments. Eye colouration showed variable retention depending on the fixative. The visibility of the posterior white gland was maintained only in specimens initially fixed in absolute ethanol, while formaldehyde-based fixatives obscured this structure. These findings highlight the importance of fixation protocols in preserving pigmentation features crucial for taxonomic work.
Length at 50% maturity (L-50) is a key input to harvest control rules and spawning biomass calculations. We estimated female L-50 for Black Sea whiting (Merlangius merlangus) from 757 individuals using nine candidate maturity ogives (logistic, probit, Hill, log-logistic, Gompertz, Weibull, Richards, Cauchy, exponential). Models were fitted under a binomial likelihood, with uncertainty quantified by non-parametric bootstrap and model support evaluated using AICc. We also derived L-10, L-90 and the transition width (L-90-L-10), assessed sensitivity to measurement resolution (rounding TL to 0.5 and 1.0 cm), and tested robustness to an isolated high-length immature observation (similar to 16 cm). Sigmoid models yielded highly consistent L-50 estimates. AICc favoured the probit model (Akaike weight = 0.40), with logistic, Hill and log-logistic models similarly supported (Delta AICc <= 1.8). The model-averaged L-50 was 13.66 cm TL (SE = 0.10; 95% CI = 13.46-13.86), with a transition width of similar to 3.5 cm. Rounding total length to 0.5 or 1.0 cm shifted L-50 by <= 0.03 cm, whereas excluding or re-coding the isolated similar to 16 cm immature observation shifted L-50 by <= 0.04 cm. These results demonstrate that standard sigmoid models provide robust and consistent L-50 estimates for Black Sea whiting, and that a multi-model framework offers transparent uncertainty for fisheries management applications.
