Marine and Freshwater Research最新文献

Global octopus catch has doubled over the past four decades and is likely to grow in importance as many key fisheries continue to decline. Lack of age data is a critical limitation in assessing the resource status of octopus. Over the past ~30 years, studies have investigated various methods to age octopus, with some methods better suited to certain species than others. However, only a small number of researchers have the hands-on knowledge to execute these methods in the laboratory. Here, we present the first step-by-step guide to ageing octopus, as well as a decision tool, which should enable readers to carry out the ageing process and make an informed decision on the most suitable method for their species. We provide guidance on age validation, increment analysis of both beaks and stylets, materials needed, as well as avenues for further research. We hope this guide will provide a starting point for researchers new to octopus ageing, and for those working with octopus species that have never been aged before. We also encourage researchers to use this guide as a forum for open discussion to support the ongoing development of effective octopus ageing methods.

Climate change and global warming has led to changes in water-quality parameters, which in turn have negative consequences for zooplankton.

To investigate the effects of various environmental stressors (pH, temperature, photoperiod, and food concentration) on the tropical freshwater microcrustacean Moina micrura.

The study examined the effects of these stressors on survival (lifespan), reproduction (days to first brood, number of broods, and total offspring), growth (individual size and total moulting), physiology (heart rate), and sex-switching effects (total male offspring).

Significant (P < 0.05) reductions in the total offspring, individual size, and heart rate of M. micrura were observed when exposed to acidic (pH 5) and alkaline (pH 9) conditions. Conversely, higher water temperatures (31°C) and longer light exposure (20 h) were found to increase total offspring and heart rate in M. micrura. Furthermore, male offspring were produced only under conditions of food scarcity (no food supply and 1 × 10² cells mL⁻¹).

Climate change has a significant effect on the life-history traits of M. micrura, a tropical cladoceran species.

Vital insights that can guide policymakers and practitioners in developing more effective strategies to safeguard and preserve tropical freshwater aquatic habitats, especially those of zooplankton species.

Currently, little information exists describing the population structure of great hammerhead sharks (Sphyrna mokarran) in Australian waters.

This study used single nucleotide polymorphisms to investigate fine-scale population structure in S. mokarran across the Indo-Pacific.

DNA was extracted from 235 individuals across six Australian locations and a Red Sea outgroup. Population parameters were calculated and visualised to test structuring across locations.

No fine-scale population structuring was observed for S. mokarran across the Indo-Pacific. However, population structuring occurred for all Australian locations when compared to the Red Sea outgroup.

Findings suggest a single stock is most likely for S. mokarran found in Australian waters. Results provide key information for understanding the broad range movements of S. mokarran and help to define the scale of management required to preserve genetic diversity in this species. The structuring between Australia and the Red Sea indicates limited gene flow and movement.

Results indicate that large-scale movements of S. mokarran could be occurring to facilitate genetic mixing. Future research focusing on individual tagging to corroborate movements would be highly beneficial to determine how far (and often) individuals are dispersing, and to note where cross-jurisdictional management, including from neighbouring regions in the Indo-West Pacific–Oceania region, are most critical.

Social and economic information is limited for coastal commercial and recreational fisheries, particularly shark fisheries, which are perceived as unsustainable and as targeting sharks for fins.

To characterise the social and economic dimensions of one of the world’s few long-standing sustainable shark fisheries.

We reviewed historic data and surveyed stakeholders to understand the economic and social dimensions of the shark fishery currently operating in Western Australia.

Since the fishery’s historic peak, there has been a substantial reduction in the number of operating vessels and ports due to management intervention. For the vessels that have remained, catches and catch rates increased through time. Fishers sold only flesh and fins, whereas processors also sold cartilage. Revenue mostly originates from the domestic sale of flesh, not fins. This fishery provides additional social and economic returns through the employment of an average of 102 people per annum, the supply of local fresh seafood to communities and the expenditure of most of operational costs in local government areas. In addition, the average annual market value through the supply chain was A$32.6 × 10⁶ (US$20.9 × 10⁶).

Our study is the first step towards a more comprehensive valuation of the societal contribution of sustainable shark fisheries.

This novel information has a range of applications, from developing social and economic objectives in fisheries harvest strategies to empowering government agencies when making decisions on natural resource management.

The Ramsar Convention is the world’s premier environmental treaty for wetlands. This perspective evaluates gender reporting in Ramsar Convention National Reports and compliance with Gender and Wetlands Resolution XIII.18. A total of 71.8% (n = 42) of the sampled nation reports (n = 133) did not submit National Reports. Zero nations provided statistics on equitable pay or pay gaps by gender. In the sampled reports, only 10 nations submitted sex-disaggregated data. Further, only 7.5% (n = 123) of the sampled National Reports (n = 133) provided sex-disaggregated gender data relevant to the Ramsar Convention. Fifteen National Reports deleted the question on gender (Section H) on from their report entirely, including Denmark and Germany. With evidence drawn from the submitted National Reports, this perspective provides concrete empirical suggestions for improving gender reporting in the future. Gender initiatives, including Resolution XIII.18 and the related Sustainable Development Goals (SDGs) have improved transparent gender reporting in the Ramsar Convention National Reports to a degree. However, on the basis of this review, there is room for improvement in national reporting.

National Reports from 2021 to 2022 were reviewed for all instances of ‘gender’ and then evaluated for national replies to Section H, focused on gender.

Five years after Resolution XIII.18, there is still a need for system-wide improvements in gender reporting, including sex-disaggregated data, and equity for women (cis and trans) for the Ramsar Convention to become compliant with Resolution XIII.18. Complying with Resolution XIII.18 is one concrete, global and measurable way for wetland science and policy to mainstream gender.

No nation has prepared a comprehensive answer to Section H on gender and wetland policy and science, as defined below; instead, nations have submitted discrete elements. The analysis of each nation’s answers showed essential elements for a comprehensive answer. In the next 5 years of gender reporting, nations have the option to learn from the past and strive to comply with Resolution XIII.18 and provide transparent sex-disaggregated data on National Heads, community stakeholders, site interpreters, site managers and equitable salary data.

Establishing baseline environmental characteristics of demersal fish habitat is essential to understanding future distribution changes and to identifying shorter-term anomalies that may affect fish density during monitoring efforts.

Our aim was to synthesise environmental data to provide near-bottom oceanographic baseline information on the Pacific halibut fishing grounds, to establish geographic groupings that may be used as co-variates in fish-density modelling and to identify temporal trends in the data.

Water-column profiler data were collected from 2009 to 2018 along the North American continental shelf, during summer fishery surveys focused on Pacific halibut.

In addition to establishing baseline information on the fishing grounds, this analysis illustrated that environmental variables can be grouped geographically into four regions that correspond to the four biological regions established by the International Pacific Halibut Commission. A spatio-temporal modelling approach is presented as an example of how to describe the relationship between environmental data and Pacific halibut distribution.

This study has highlighted the efficacy of environmental data in analysing fish distribution and density changes.

Oceanographic monitoring provides the ability to detect annual anomalies such as seasonal hypoxic zones that may affect fish density and to establish baseline information for future research.

Seagrass meadows are highly productive habitats with a vast species diversity that perform multiple ecosystem services. The fauna associated with these environments is responsible for many of the ecosystem services. Therefore, the fauna composition and functional characteristics should be considered in studies addressing seagrass meadows.

This study aimed to evaluate the differences in the taxonomic and functional compositions of the macrofauna associated with Halodule wrightii (Ascherson) meadows subject to different settings of habitat characteristics in the shallow coastal regions of the north-eastern coast of Brazil.

We used the Hill diversity series to estimate taxonomic diversity, whereas functional diversity was estimated through biological-trait analyses.

Distinct patterns of taxonomic and functional diversities were observed among meadows. However, the composition of functional traits diverged more. Lower taxonomic and functional diversity were observed in the Suape meadows, with values mainly related to the low organic matter content. Catuama meadows presented opposite results, associated with higher organic matter and plant density.

The meadow heterogeneity can influence the associated macrofauna and its functional characteristics.

These results are highly relevant for predicting the consequences of changes in seagrass meadows and how this affects the functioning of these ecosystems.

Within the western and central North Pacific Ocean stock of striped marlin (Kajikia audax), reproductive information is lacking for the central North Pacific.

To derive estimates of sex-specific functional maturity ogives, eye-to-fork length at 50% maturity, reproductive phase composition, spawning season and sex ratios by sampling the Hawaii-based pelagic longline fishery.

Gonad histology was exclusively used to confirm sex and estimate all reproductive life history traits.

Females spawn in May–July; males are capable of spawning year-round. Best length at 50% maturity estimates were based on datasets restricted to the female spawning season (eye–fork length for females 152.2 cm and for males 109.0 cm). Length distributions and sex ratios are seasonally dynamic around Hawaii and differ from those in other Pacific regions.

Length-at-maturity estimates for the central North Pacific are lower than all sex-specific estimates reported from other Pacific regions.

The new maturity estimates will improve determinations of stock resilience and productivity in upcoming international assessments.

Carinotetraodon travancoricus is a threatened ornamental aquarium fish endemic to Western Ghats (WG) biodiversity hotspot of India and indiscriminate collection of this species resulted in a severe population decline.

To understand the impacts of wild collection of C. travancoricus for aquarium-fish trade, information on their population status and reproductive characteristics is required.

Specimens for the present study were collected from the Chalakudy River of WG and growth, mortality, exploitation and reproductive characteristics of C. travancoricus were investigated.

The natural mortality of the species was higher than the fishing mortality. The peak spawning period of the species was from May to September. Length at first maturity (L₅₀) for males and females was estimated to be 18.4 and 18.1 mm respectively.

The stock of C. travancoricus in the Chalakudy River may be in near full exploitation under current harvesting strategy. The lower value of length of first capture than size at first maturity indicated that C. travancoricus is likely to be captured before it matures and breeds, subsequently contributing to declining recruitment.

A combination of different strategies (closed fishing seasons, mesh-size regulation and no-fishing areas) will improve sustainable management and conservation of species.

The emergence of new methods for the analysis of environmental samples, such as massive parallel sequencing, creates a unique opportunity for studying the spread of viral nucleic acids in the environment.

The purpose of the article was to evaluate the diversity of ribonucleic acid (RNA) sequences of coronaviruses in the sample of water collected in the Small Aral Sea.

Nucleic acid sequencing of water samples collected from the Small Aral Sea was performed to assess diversity and spread of viruses.

A surprisingly high content of RNA fragments from coronaviruses was shown in aqueous samples. The presence of a wide variety of virus hosts from rodents and bats to mammals and humans was detected. Taxonomic classification of metagenomic data obtained after sequencing of nucleic acids of the Small Aral Sea samples showed the presence of coronaviruses RNA fragments of different genera.

This study showed that water samples from environmental sites can be used to assess the distribution and diversity of RNA fragments of coronaviruses. Continued monitoring of water samples could help establish a surveillance system for the early detection and monitoring of coronaviruses.

On the basis of the obtained results, it is hypothesised that the analysis of viromes and microbiomes creates new opportunities for studying the spread of viruses in the environment, which is a necessary fact for the development of possible anti-epidemic measures.