Marine and Fishery Sciences (MAFIS)

Nutritional characterization of Trachurus lathami discarded by the Argentine fishing industry: first step towards the sustainable valorization of the species

2024-03-05T11:25:38+00:00

In the Argentine Continental Shelf pelagic fisheries, rough scad (Trachurus lathami) is incidentally caught, being discarded by the commercial fleet despite its high abundances. With the aim of promoting the sustainable use of this species, the nutritional characterization of T. lathami is reported here for the first time. High protein (16%) and lipid (5.4%) content in whole individuals indicated that this is a moderately fat species. In the edible portion, within total lipids (4.8%), the n-3 polyunsaturated fraction was represented by docosahexaenoic (16.8%) and eicosapentaenoic (5.6%) acids. Results encourage potential strategies towards the developing of restructured products for human consumption.

Changes on quality parameters and sensory attributes of the Patagonian red octopus (Enteroctopus megalocyathus) meat under different postharvest treatments

2024-03-05T13:52:37+00:00

Enteroctopus megalocyathus is an important commercial resource harvested by small-scale fisheries from Argentina and Chile, with limited access to cooling preservation methods. In this sense, the use of alternative postharvest conservation methods could be useful to preserve the good quality of the raw product. The effect of postharvest treatments using seawater immersion, flaked ice, 0.1% acetic acid, and a control was investigated on raw octopus during storage at 4 °C for seven days. Under these treatments, changes in physical, chemical, microbiological parameters and sensory attributes were evaluated. Results showed that for control and seawater treatments, octopus became unacceptable at the third day. Ice and 0.1% acetic acid treatments exhibited better physical, chemical and microbiological quality parameters along the storage days. Based on sensory attributes, octopus meat immersed in 0.1% acetic acid remained within the limits of acceptability until the fifth day, while the ice treatment extended the initial quality at least for seven days. Thus, 0.1% acetic acid would become an economical and easily applicable method during postharvest handling of E. megalocyathus fishery.

Floating marine debris in two pelagic ecosystems of the southwestern Atlantic off Argentina

2024-03-08T18:43:18+00:00

In 2012 and 2013, observational surveys from seismic vessels were conducted to evaluate the abundance and composition of floating marine debris (FMD) in the east of Tierra del Fuego (TDF), Argentina, and the Brazil/Malvinas Confluence zone (BMC), respectively. The mean abundance of FMD varied significantly between sampled ecosystems, with higher loads in TDF (mean abundance = 6.15 ± 8.84 items) when compared to BMC (3.31 ± 6.83 items). Plastics dominated the composition of FMD at both ecosystems (> 80%), followed by foamed plastics. Within the plastic category, bags were the most abundant item, followed by wrappers, and bottles, among others. According to its color, white/clear, and multicolor debris were the most abundant. The main presumed source of FMD was domestic activities, followed by fisheries-related, and construction. This is the first study demonstrating the utility of using seismic vessels as a platform for monitoring FMD in waters within the Argentine continental shelf and adjacent waters.

Morphological, chemical and growth patterns characterization in shells of Phorcus species along the northeastern coasts of Tunisia

2024-03-13T14:02:47+00:00

This work is a characterization of the morphometry, the relative growth and the metal contamination degree of the shells of two species belonging to Phorcus genus along the northeastern rocky coasts of Tunisia. The gastropods were sampled from nine locations during the winter 2017. Our findings suggested a spatial morphometric variability probably linked to the extent of the continental shelf, the coasts’ geomorphology, the dynamics of water masses, the predation and the competition effects. Furthermore, the shell investigation allowed the study of the growth pattern and indicated that the development in shell size was faster than the increase in weight. Moreover, the use of Phorcus shells as bioindicators of long-term metal contamination seems to be of growing interest, due to their abundance, high longevity, easy sampling and ecobiological features, both in a scientific and ecosystem management perspective that aims to the establishment of conservation measures targeting marine coastal environments.

Identifying vulnerable marine ecosystems from imagery in the Uruguayan continental shelf

2024-04-03T18:09:13+00:00

Scientific surveys employing remotely operated vehicles (ROVs) provide valuable imagery for identifying Vulnerable Marine Ecosystems (VMEs). However, there is presently no established framework for distinguishing VMEs from these images. While existing guidelines effectively address certain habitat types, such as scleractinian reefs, dense octocoral gardens, and chemosynthetic ecosystems, achieving consensus becomes more challenging for other habitats. Our investigation centered on two key localized rocky outcrops on the Uruguayan shelf, conducting ROV dives to explore these environments. This study aims to evaluate initial global consensus guidelines for VME identification from imagery and discuss the suitability of these criteria, and report the existence of Hard Bottom Soft Coral Gardens and Sponge associations in the inner Uruguayan shelf. Recognizing these habitats is of utmost importance for the Uruguayan government, which has expressed the intent to safeguard ecologically representative and well-connected systems crucial for marine biodiversity.

Women’s participation, challenges and problems encountered in major fish markets during the COVID-19 pandemic in Davao, Philippines

2024-04-15T14:06:02+00:00

Women fish vendors actively participate in the fishery sector but they face various challenges regarding their financial capital and opportunities. There is a power imbalance within the market as men seem to dominate and women hold no power or voice to protect their rights. This study provides valuable insights regarding the perceptions and experiences of these women in the Davao region, by not only focusing on the role of women in fisheries and major fish markets in Mindanao, Philippines, but also on their contribution and the challenges they meet. We have conducted semi-structured field interviews with women fish vendors (n = 99) and in-depth follow-up interviews to validate the results (n = 80). Among respondents, 90% in Tagum, 80% in Panabo, and 75% in Davao City were vendors who did not own their stalls. Despite women’s active involvement in fish trading activities such as fish vending, fish brokering, and financing in the market, many of them do not have stalls on their own. It was found that women participate in the fish marketing sector because they received previous training from family members involved in the business (29%), or they wanted a well-paying job (19%), or it was their only economic opportunity (14%). Another reason was profitability (9%) to support their families (9%) and children (8%). Common problems encountered by women in the fish market included a decline in customers (40%), work exhaustion due to the combination of their market and domestic duties (14%), and rude customers and employers (10%). In addition, women also reported challenges regarding mobile vendors (9%), low fish prices (8%), and not having access to financial credit (8%). Many of the women support their husbands by providing additional income for their families. Overall, women fish vendors play a critical role in the local economy of their villages and families. This implies that greater support is needed for women to have financial access to fishing businesses and become beneficiaries of training and livelihood development programs while helping their families overcome food insecurity and poverty.

Recirculating aquaculture systems affects hematological parameters and increases ectoparasite susceptibility in Nile tilapia Oreochromis niloticus

2024-04-17T11:26:25+00:00

We herein evaluated the hematology and parasitology of Nile tilapia previously raised in an earthen pond and transferred to a recirculating aquaculture system (RAS) to verify any possible influence of RAS on such health parameters. For this, 780 tilapias with an initial average weight and length of 91.05 ± 27.08 g and 17.45 ± 1.91 cm, respectively, were distributed in three tanks (2.0 m³) attached to the RAS, where they remained for 54 d. Throughout the period, water quality parameters remained within the range suitable for the cultivation of the species. Tilapia growth performance was satisfactory in the RAS, reaching a final biomass of close to 300 kg and survival of 98%. Hematological and parasitological analyses at the end of 54 d showed possible stress in RAS, with a significant increase in neutrophils from 12.15 ± 6.66 (earthen pond) to 21.43 ± 11.68% (RAS) and erythrocytes from 1.81 ± 0.24 (earthen pond) to 2.13 ± 0.14 (RAS), and a significant decrease in lymphocytes from 22.4 ± 2.66 (earthen pond) to 13.67 ± 3.38 (RAS). Furthermore, parasitological analysis showed a significant increase in the number of parasitized fish (25% to 63%) and abundance (3.55 ± 6.44 to 9.37 ± 9.99) after 54 d. It was concluded that tilapia cultivation in RAS can cause hematological changes and increase parasitism.

Application of Benford’s Law to the Argentine whitemouth croaker (Micropogonias furnieri) fishery

2024-06-25T15:44:09+00:00

In the field of statistical data, both in the natural and social sciences, it has been observed that the distribution of the first, second and first two digits in real data frequently follows a pattern known as ‘Benford’s law’. This law has recently been used as a tool to identify anomalies in different databases, suggesting in some cases the possibility of fraud. It was observed that ‘genuine’ data digits tend to follow the law, while manipulated data digits do not. In this work, we explore their applicability beyond the financial sphere, investigating whether they can detect irregularities in scientific data, specifically in the official catch statistics of the Argentine whitemouth croaker (Micropogonias furnieri) fishery. To this end, we compare the frequency of the first, second and first pair of digits of the capture with the expected distribution using the mean absolute deviation (MAD). We implemented a methodology based on Monte Carlo simulations and the Kolmogorov-Smirnov test to calculate critical values of the MAD conformance test, addressing the unique nature of data and the variability in sample size. The conducted analysis suggested the presence of anomalies that could denote unusual patterns warranting further detailed investigation. In the field of assessment, management/administration, and conservation of fishing resources, the reliability of catch data is essential. The use of Benford’s law could optimize the selection of information used to develop indicators and reduce uncertainty in estimating the population status of resources.

Ecological implications of unintentional aquaculture escapees: an overview of risks, remediation strategies and knowledge gaps in the aquaculture sector of India and riparian East African countries

2024-04-29T13:44:43+00:00

The global expansion of aquaculture has driven significant technological advancements, including raceways, Integrated Multitrophic Aquaculture (IMTA) and marine offshore cages. However, unregulated aquaculture escapees pose a severe threat to aquatic biodiversity, acting as a potential time bomb for the entire ecosystem. Addressing this issue requires a comprehensive understanding of the impact of unintentional escapees on aquatic ecosystems, particularly in India and riparian East African countries (Kenya, Uganda, and Tanzania). Using an exploratory research design drawing from various peer-reviewed sources, this study outlines the dynamic growth of aquaculture in these countries, identifies high-impact escape incidents, and correlates risks and remedies with global cases, especially in regions such as Norway, Scotland, Ireland, Colombia, and the United States, where serious incidents of aquaculture escapees have been reported. The research categorizes aquaculture development trends, discusses mechanisms of escapee impact, proposes remedies, assesses methods and inferential strength, and highlights gaps in the existing literature. The study revealed complex ecological shifts caused by aquaculture escapees from invasive non-native fish species, affecting predation, competition, and genetic diversity. Escaped fish from aquaculture facilities pose a significant threat to aquatic biodiversity, especially in the study regions. The escalating risk of unintentional escapes was highlighted in India and three East African countries. To mitigate this, the study proposes integrating escapee management into national fisheries systems, amending fisheries laws, holding fish farmers accountable for aquaculture system failure, and developing comprehensive regulations for non-native species in aquaculture within the study regions. It is recommended to standardize the planning for aquaculture facilities and implement emergency plans, training, local mobilization and further research on the impact thresholds of aquaculture escapees in the study regions. Ecological education in aquaculture communities and the recognition of the role of translational scientists are crucial for the dissemination of knowledge. Urgent government action is needed to address unreported aquaculture escapes, preventing further ecosystem degradation and ensuring global aquaculture sustainability.

Occurrence of the Blue button Porpita porpita along the Italian Ionian and Tyrrhenian coasts

2024-04-11T15:06:56+00:00

New individuals of Porpita porpita were detected along the Italian coasts of the Mediterranean Sea. In recent years, due to warming Mediterranean waters, the species has spread even further. This observation opens new horizons for further reports of this species in the Ionian and Tyrrhenian Seas of Italy.