Research

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16 pages, 5816 KiB

Open AccessArticle

Impacts of the Establishment of Biofoulants on Greek Aquaculture: Farmers’ Expert Knowledge

by Dimitrios Tsotsios, Dimitrios K. Moutopoulos, Athanasios Lattos, Basile Michaelidis and John A. Theodorou

J. Mar. Sci. Eng. 2023, 11(5), 1077; https://doi.org/10.3390/jmse11051077 - 19 May 2023

Cited by 1 | Viewed by 1007

Abstract

Ascidians’ bioaccumulation is frequently responsible for the massive growth of certain species, causing detrimental effects on aquaculture facilities. The goal of this study is to provide, for the first time in the Eastern Mediterranean, information on biofoulant species in Greek mussel farms over [...] Read more.

Ascidians’ bioaccumulation is frequently responsible for the massive growth of certain species, causing detrimental effects on aquaculture facilities. The goal of this study is to provide, for the first time in the Eastern Mediterranean, information on biofoulant species in Greek mussel farms over a long time scale and to describe the best management strategies that will reduce costs while preventing and controlling these biofoulants. An interview survey was conducted to assess mussel farmers’ expert judgment on non-endemic ascidians as well as their opinions on the magnitude of the invasion’s impacts. The results show that ascidians and, to a lesser extent, sponges exhibited the highest intensities in mussel farm units during the last 20 years, whereas gastropod invasion was limited and observed after 2015. Ascidians exhibited the most significant impact on the final product, whereas sponges showed a moderately negative impact, with reduced amounts of flesh being the most important effect. The cost of farming management only rose with ascidians and sponges and was mostly impacted by damages to maintenance and labor and, to a lesser extent, fuel. All invasive species affected the operational cost of production at a rate of 21–50%, which peaked from July to September. The above problems are increasingly aggravating in cases where farm units undergo production shutdown due to plankton bloom. Preventive management action against the establishment of biofoulants in Greek mussel aquaculture is of paramount importance. Full article

(This article belongs to the Special Issue Marine Fish and Invertebrate Aquaculture)

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11 pages, 1219 KiB

Open AccessArticle

Phylogenetic Affinities of Acanthopleurinae Dall, 1889 Chitons (Mollusca: Polyplacophora: Chitonidae) from Jazan Coast in the Red Sea and Western Indo-Pacific

by Hassien Alnashiri, Liju Thomas, Maqbool Thaikkottathil, Siby Philip, Ranjeet Kutty, Sureshkumar Sivanpillai and Ali Mohammed Abo Rasain

J. Mar. Sci. Eng. 2023, 11(1), 158; https://doi.org/10.3390/jmse11010158 - 09 Jan 2023

Cited by 3 | Viewed by 1567

Abstract

Chitons (Polyplacophora) are marine molluscs that mostly inhabit rocky intertidal shores. Their biological and phylogenetic studies are comparatively sparse in the western Indo-Pacific regions. In addition, chitons belonging to the subfamily Acanthopleurinae Dall, 1889, collected from the Andaman Sea of the northeastern Indian [...] Read more.

Chitons (Polyplacophora) are marine molluscs that mostly inhabit rocky intertidal shores. Their biological and phylogenetic studies are comparatively sparse in the western Indo-Pacific regions. In addition, chitons belonging to the subfamily Acanthopleurinae Dall, 1889, collected from the Andaman Sea of the northeastern Indian Ocean and the Jizan coast of Saudi Arabia were sequenced and analyzed to study the phylogenetic affinities. The analysis was carried out using a single locus dataset (cytochrome oxidase 1) generated during the present study and integrated with sequences retrieved from GenBank. Acanthopleura gemmata (Blainville, 1825) from India was linked to Acanthopleura vaillantii Rochebrune, 1882, from the Saudi Arabia coast. Squamopleura miles (Carpenter in Pilsbry, 1893) from the Indian coast forms a separate clade representing the genus. Furthermore, the results illustrate several significant instances of misplacement of several species under the wrong genus and the existence of cryptic species within the genera Acanthopleura and Squamopleura. An integrated approach is required to better understand these important intertidal groups’ taxonomy, systematics, and biogeography. Full article

(This article belongs to the Special Issue Marine Fish and Invertebrate Aquaculture)

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15 pages, 4492 KiB

Open AccessArticle

Value Chain for Non-Indigenous Bivalves in Greece: A Preliminary Survey for the Pearl Oyster Pinctada imbricata radiata

by John A. Theodorou, Vasileios Minasidis, Athina Ziou, Alexandra S. Douligeri, Marios Gkikas, Evangelia Koutante, George Katselis, Orestis Anagnopoulos, Nikos Bourdaniotis and Dimitrios K. Moutopoulos

J. Mar. Sci. Eng. 2023, 11(1), 95; https://doi.org/10.3390/jmse11010095 - 04 Jan 2023

Cited by 2 | Viewed by 1443

Abstract

The present study investigates through an integrated survey, for the first time in Greek shellfish market, the marketing distribution towards a new edible shellfish product that of the non-indigenous pearl oyster Pinctada imbricata radiata. The survey conducted through personal interviews on sector [...] Read more.

The present study investigates through an integrated survey, for the first time in Greek shellfish market, the marketing distribution towards a new edible shellfish product that of the non-indigenous pearl oyster Pinctada imbricata radiata. The survey conducted through personal interviews on sector entrepreneurs/staff of the supply (i.e., shellfish producers, wholesalers, fishmongers, owners of restaurants). Internet-based quantitative research was also conducted to explore the market supply of the pearl oyster covering all nine regional units of Greece. The market for pearl oyster seems to be there as a substitute of the major commercial species in seasons of shortages. There is a specimen mislabeling throughout Greece, thus, extraction of significant information about the market supply of pearl oyster is deficient. Further knowledge on the bivalve shellfish value chain is needed, to define how the wild and the farmed species (mussels) interact in the market and in the distribution channels, toward a product-easy to use in the supply chain and friendly to the consumer. Findings also raises additional concerns as a priority for conservation, and the current practices do not satisfy the Common Fisheries Policy in terms of traceability. Full article

(This article belongs to the Special Issue Marine Fish and Invertebrate Aquaculture)

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16 pages, 3213 KiB

Open AccessArticle

Sea Anemone Aiptasiomorpha minuta (Verrill, 1867) as a Possible Agent to Control Biofouling in Oyster Culture and the Optimal Conditions for Its Mass Rearing under Laboratory Conditions

by Mary Grace Sedanza, Hee-Jin Kim and Cyril Glenn Satuito

J. Mar. Sci. Eng. 2022, 10(10), 1490; https://doi.org/10.3390/jmse10101490 - 14 Oct 2022

Viewed by 1905

Abstract

The potential use of the sea anemone Aiptasiomorpha minuta as an agent for controlling biofouling on cultured oysters and the optimum culture conditions for its mass culture were evaluated. Field experiments showed that nineteen species (eight phyla), including two seaweed species, sponges, hydroids, [...] Read more.

The potential use of the sea anemone Aiptasiomorpha minuta as an agent for controlling biofouling on cultured oysters and the optimum culture conditions for its mass culture were evaluated. Field experiments showed that nineteen species (eight phyla), including two seaweed species, sponges, hydroids, bryozoans, mollusk/bivalve species, barnacles, and tunicates were found as biofouling assemblages on the oyster collectors. The ability of A. minuta to accumulate biomass on oyster collectors, thus, minimizing colonization by problem species; was also demonstrated to promote better oyster growth, condition index, and survival. Favorable mass culture conditions of A. minuta in laboratory trials were found at 28 °C, fed with Artemia salina (1000 individuals/day), and at 23 psu for the optimum temperatures, diet regimen, and salinity, respectively. These mass culture conditions could be useful for the purpose of producing enough biomass for attaching the sea anemones, A. minuta, to oyster collectors. The use of A. minuta could be a preventive strategy against biofouling that may be useful for oyster farmers; it is safe from the viewpoint of food hygiene, and is also environment-friendly. Full article

(This article belongs to the Special Issue Marine Fish and Invertebrate Aquaculture)

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17 pages, 2009 KiB

Open AccessArticle

Effect of Agricultural By-Products as a Carbon Source in a Biofloc-Based System on Growth Performance, Digestive Enzyme Activities, Hepatopancreas Histology, and Gut Bacterial Load of Litopenaeus vannamei Post Larvae

by Abdallah Tageldein Mansour, Ola A. Ashry, Mahmoud S. El-Neweshy, Ahmed Saud Alsaqufi, Hagar S. Dighiesh, Mohamed Ashour, Mahmoud S. Kelany, Mohamed A. El-Sawy, Mohamed M. Mabrouk, Eman M. Abbas and Zaki Z. Sharawy

J. Mar. Sci. Eng. 2022, 10(10), 1333; https://doi.org/10.3390/jmse10101333 - 20 Sep 2022

Cited by 6 | Viewed by 2045

Abstract

The present study evaluated the influence of different commercial agricultural by-products as a carbon source in a bifloc-based (BFT) culture system on growth performance, whole-body proximate composition, digestive enzyme activities, gut microbial abundance, and hepatopancreas histology of Pacific whiteleg shrimp, Litopenaeus vannamei post [...] Read more.

The present study evaluated the influence of different commercial agricultural by-products as a carbon source in a bifloc-based (BFT) culture system on growth performance, whole-body proximate composition, digestive enzyme activities, gut microbial abundance, and hepatopancreas histology of Pacific whiteleg shrimp, Litopenaeus vannamei post larvae (Pls). Three groups were designed, the first group was the control group, where the shrimp was reared in clear water (without carbon source addition and water exchange rate of 100% two times a week) and fed with a commercial diet, in the second and third groups shrimp were reared in BFT systems using two different carbon sources, sugarcane bagasse (SB) and rice bran (RB) without additional feeding or water exchange. The initial stocking density was 16 Pls/liter with an average individual shrimp weight of 0.01 ± 0.002 g and age (PL20). The experiment lasted 90 days. The water quality parameters were maintained at optimum levels during the experiment. The final body weight and specific growth rate of shrimp were significantly (p ≤ 0.01) higher in the control group than those reared in both SB and RB-based BFT. Meanwhile, the survival rate was significantly (p < 0.05) higher in BFT groups than in the control. The protease activity in shrimp stomach did not differ significantly. Meanwhile, protease, lipase, and amylase in the intestine showed a significant increase (p < 0.01) in BFT groups than those obtained in the control group. The total heterotrophic bacteria were significantly (p < 0.05) higher in BFT groups. Furthermore, the hepatopancreas histological status of shrimp reared in the SB-based BFT group showed an increase in the hepatopancreas tubules in the distal and B-cell zones (blister-like cells) by 16.83 and 34.89%, respectively, compared to the control. This study revealed that BFT could be used as a natural feed without artificial diets, which influenced the gut microbiota of shrimp, increased digestive enzyme activities, as well as improved the histological structure of the hepatopancreas of shrimp. However, the success of this conditions under high stocking density still needs more investigation. Full article

(This article belongs to the Special Issue Marine Fish and Invertebrate Aquaculture)

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15 pages, 2247 KiB

Open AccessArticle

An IMTA in Greece: Co-Culture of Fish, Bivalves, and Holothurians

by Dimitra Chatzivasileiou, Panagiotis D. Dimitriou, John Theodorou, Ioanna Kalantzi, Iordanis Magiopoulos, Nafsika Papageorgiou, Paraskevi Pitta, Manolis Tsapakis and Ioannis Karakassis

J. Mar. Sci. Eng. 2022, 10(6), 776; https://doi.org/10.3390/jmse10060776 - 03 Jun 2022

Cited by 10 | Viewed by 2793

Abstract

Integrated multitrophic aquaculture (IMTA) is an innovative mariculture methodology that reduces the environmental footprint and increases the profitability of the farm. It combines the cultivation of species belonging to different trophic levels, simulating a natural food web. In this study, five Mediterranean species [...] Read more.

Integrated multitrophic aquaculture (IMTA) is an innovative mariculture methodology that reduces the environmental footprint and increases the profitability of the farm. It combines the cultivation of species belonging to different trophic levels, simulating a natural food web. In this study, five Mediterranean species were co-cultured in three operating fish farms in the Aegean (E. Mediterranean) Sea with different trophic conditions. The co-cultivated species were sea bream (Sparus aurata), European sea bass (Dicentrarchus labrax), Mediterranean mussel (Mytilus galloprovincialis), rayed pearl oyster (Pinctada imbricata radiata), and sea cucumber (Holothuria polii). Bream, bass, and mussels were cultivated according to the traditional on-growing methods (fish cages and longlines), whereas the pearl oysters and sea cucumbers were cultivated in baskets designed specifically for oyster farms. To estimate the growth of the co-cultivated species, growth indicators were calculated using length and weight measurements. Furthermore, the growth measurements from co-cultivated species were compared to the respective ones from natural populations. All the species showed high survival rates in the integrated multitrophic aquaculture (IMTA) conditions. Pearl oysters and Mediterranean mussels had positive growth in fish farms with high concentrations of nutrients. Mussel condition index (CI) was 42% in Aquaculture 1 (Aq1) and 33% in Aquaculture 2 (Aq2), compared to 35% in a typical Mediterranean mussel farm. Pearl oysters CI in Aq1 was 53%, in Aq2 56%, in Aquaculture 3 (Aq3) 19%, and in natural populations ranging from 30% to 45%. In contrast, holothurians did not gain weight under the fish cage regime despite the high survival rate. Their final total weight was 17.3 g in Ag1, 8.3 g in Aq2, and 18.3 g in Aq3, but in the natural population, the mean weight was 80 g. Full article

(This article belongs to the Special Issue Marine Fish and Invertebrate Aquaculture)

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18 pages, 7871 KiB

Open AccessArticle

Seasonal Pattern of the Effect of Slurry Ice during Catching and Transportation on Quality and Shelf Life of Gilthead Sea Bream

by Athina Ntzimani, Rafael Angelakopoulos, Natalia Stavropoulou, Ioanna Semenoglou, Efimia Dermesonlouoglou, Theofania Tsironi, Katerina Moutou and Petros Taoukis

J. Mar. Sci. Eng. 2022, 10(3), 443; https://doi.org/10.3390/jmse10030443 - 19 Mar 2022

Cited by 3 | Viewed by 2372

Abstract

The objective of the present study was the evaluation of the effect of slurry ice, as an alternative cooling medium during harvesting and transportation, on the quality parameters (e.g., microbiological stability, sensory attributes, physicochemical changes) and shelf life of fish. The effect of [...] Read more.

The objective of the present study was the evaluation of the effect of slurry ice, as an alternative cooling medium during harvesting and transportation, on the quality parameters (e.g., microbiological stability, sensory attributes, physicochemical changes) and shelf life of fish. The effect of seasonal variability of seawater temperature on fish preservation using the tested cooling media was also investigated. Gilthead sea bream (Sparus aurata) was slaughtered and transported in different mixtures of conventional flake ice and slurry ice for 24 h. Three mixtures of ice were tested as T: slaughtered in flake ice and transported in flake ice (control), TC: slaughtered in slurry ice and transported in flake ice, T50: slaughtered and transported in slurry ice 50%–flake ice 50%. Samples were subsequently stored isothermally at 0 °C for shelf-life evaluation. Three independent experiments were performed at three different periods, i.e., January, April, and September, referring to a sea water temperature range of 13.3–26.8 °C. Higher sea water temperatures at catching led to lower microbial growth rates and proteolytic enzyme activities and longer shelf life of refrigerated whole fish. The partial replacement of conventional flake ice with slurry ice improved the quality and extended the shelf life of fish at 0 °C by 2–7 days. The results of the study support that the use of slurry ice may enable better quality maintenance and significant shelf-life extension of whole gilthead sea bream. Full article

(This article belongs to the Special Issue Marine Fish and Invertebrate Aquaculture)

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15 pages, 2266 KiB

Open AccessArticle

Growth Heterogeneity of Chub Mackerel (Scomber japonicus) in the Northwest Pacific Ocean

by Kai Cai, Richard Kindong, Qiuyun Ma, Xiaobin Han and Song Qin

J. Mar. Sci. Eng. 2022, 10(2), 301; https://doi.org/10.3390/jmse10020301 - 21 Feb 2022

Cited by 3 | Viewed by 2258

Abstract

Chub mackerel (Scomber japonicus) is a pelagic fish widely distributed in temperate and subtropical zones throughout the Indian and Pacific Oceans and is commercially exploited, particularly in the North Pacific. Although highly targeted in this region, little is known about their [...] Read more.

Chub mackerel (Scomber japonicus) is a pelagic fish widely distributed in temperate and subtropical zones throughout the Indian and Pacific Oceans and is commercially exploited, particularly in the North Pacific. Although highly targeted in this region, little is known about their life history aspects. The objectives of this study are to evaluate the growth heterogeneities and ageing analysis of this species. We describe the length-at-age, weight-at-length, relative condition factor relationships, spatiotemporal heterogeneity and compare estimated growth parameter values to those reported from other regions. This study used data obtained from Chinese fishing vessels collected from 2016–2020 in the northwest Pacific Ocean. Length-weight data from 2686 specimens (40–294 mm, fork length; 0.8–311.8 g body weight) were analyzed, and the Length-weight relationship was W = (1.41 × 10⁻⁶) × FL^3.37. Seven linear mixed-effects models (LMEM) were used to analyze the heterogeneity of length-weight relationships of Chub mackerel. The Length-weight relationships for Chub mackerel were best described by a model with random effects with both year and season (spring, summer, autumn) with the scalar parameter a. Age estimates were obtained from 175 specimens, and the length-at-estimated ages relationship was described using three non-linear candidate growth models. The von Bertalanffy growth model fit the data best for Chub mackerel in the northwest Pacific Ocean. Comparing the results to that of previous studies, we observed that individual Chub mackerel exhibited a slower growth rate than that observed in previous studies. In addition, relative condition factors varied among years, seasons, and regions. Information presented in this study provides an effective scientific basis for stock assessment and fishery management of Chub mackerel in the northwest Pacific Ocean. Full article

(This article belongs to the Special Issue Marine Fish and Invertebrate Aquaculture)

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16 pages, 3088 KiB

Open AccessArticle

Mapping of Greek Marine Finfish Farms and Their Potential Impact on the Marine Environment

by George Katselis, Konstantinos Tsolakos and John A. Theodorou

J. Mar. Sci. Eng. 2022, 10(2), 286; https://doi.org/10.3390/jmse10020286 - 18 Feb 2022

Cited by 4 | Viewed by 3205

Abstract

The Greek marine aquaculture has a leading role in the Mediterranean mariculture industry, mainly in the export sector and its prominent contribution to the country’s economy. In the present study, the spatial distribution of Greek finfish farming activity and its potential impact zones [...] Read more.

The Greek marine aquaculture has a leading role in the Mediterranean mariculture industry, mainly in the export sector and its prominent contribution to the country’s economy. In the present study, the spatial distribution of Greek finfish farming activity and its potential impact zones on the marine environment were estimated and mapped. The Greek coastline was scanned via Google Earth satellite images for the period of June 2016 to May 2017, with 433 fish farm cage arrays being detected. For each cage array, the zones at different distances corresponding to various type of impacts were mapped by means of GIS technologies. Seventy-five spatial clusters of cage arrays (sc) were revealed, including cage arrays with shown connectivity. As per the findings, Greek marine fish farming activity shows a high level of spatial aggregation but with a relative moderate intensity of impacts due to legal constraints, which play a crucial role in controlling the spatial distribution of activity at a local, regional, and national scale. The results reflect an important source of geodata, necessary for the spatial planning of activity, the monitoring of environmental impacts, and the research itself. Full article

(This article belongs to the Special Issue Marine Fish and Invertebrate Aquaculture)

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18 pages, 3169 KiB

Open AccessFeature PaperArticle

Investigating the Acceptance of a New Bivalve Product in the Greek Shellfish Market: The Non-Indigenous Pearl Oyster Pinctada imbricata radiata

by Dimitrios K. Moutopoulos, Vasileios Minasidis, Athina Ziou, Alexandra S. Douligeri, George Katselis and John A. Theodorou

J. Mar. Sci. Eng. 2022, 10(2), 251; https://doi.org/10.3390/jmse10020251 - 12 Feb 2022

Cited by 3 | Viewed by 2235

Abstract

Greece exhibits the lowest seafood per capita consumption amongst European Mediterranean countries, and the investigation of consumer attitudes to new seafood products would bridge the gap among producers and consumers by promoting the vertical integration of the supply chain. However, limited information exists [...] Read more.

Greece exhibits the lowest seafood per capita consumption amongst European Mediterranean countries, and the investigation of consumer attitudes to new seafood products would bridge the gap among producers and consumers by promoting the vertical integration of the supply chain. However, limited information exists about consumer preferences for bivalves in the Mediterranean and for wild bivalves in particular. The present study aims to investigate, for the first time, consumers’ attitudes towards the purchase and consumption of bivalves, and more specifically, towards the edible pearl oyster Pinctada imbricata radiata, in the Greek shellfish market. Adult participants from the entire country completed a questionnaire covering the basic marketing aspects of bivalve and pearl oyster consumption, such as choice, purchase, reasons for consuming bivalves, confidence in product’s hygiene certification, media influence, etc. Data analysis included uni- and multi-variate statistics to examine the possible relations between the consumers’ demographics and socio-economic characteristics, and bivalve marketing aspects. Results showed that the majority of Greek consumers chooses traditional shellfish shops for purchasing pearl oysters, prefers a certification of quality, and trusts the confirmation provided by the veterinary authorities. Consumers’ attitudes vary considerably according to their demographics and socio-economic characteristics. Multivariate models revealed that the married, highly educated consumers that live in urban places were more reluctant to try new shellfish products and to accept an innovative way of market supply. The results reflect the positive attitude of Greek consumers towards the consumption of pearl oyster, a fact that would be helpful for decision makers in the planning of production, which in turn would promote bivalve consumption in the Greek shellfish market. Full article

(This article belongs to the Special Issue Marine Fish and Invertebrate Aquaculture)

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13 pages, 1701 KiB

Open AccessArticle

Use of Local Ecological Knowledge on the Natural Recruitment of Bivalve Species of Commercial Exploitation in a Natura Area

by John A. Theodorou, Vasilis Akrivos, George Katselis and Dimitrios K. Moutopoulos

J. Mar. Sci. Eng. 2022, 10(2), 125; https://doi.org/10.3390/jmse10020125 - 18 Jan 2022

Cited by 4 | Viewed by 1674

Abstract

The current study provides valuable insight into the ecological risks and decline of the bivalve fishery and biodiversity in the Amvrakikos Gulf over the last 50 years through a triangulation of information from in situ surveys and expert judgment, supplemented with historical archives. [...] Read more.

The current study provides valuable insight into the ecological risks and decline of the bivalve fishery and biodiversity in the Amvrakikos Gulf over the last 50 years through a triangulation of information from in situ surveys and expert judgment, supplemented with historical archives. In situ sampling showed that bivalve species composition was a typical composition of benthic fauna consisting of the olive green cockle, Cerastoderma glaucum, the grooved carpet shell, Ruditapes decussatus, and the Mediterranean mussel, Mytilus galloprovincialis. Interviews confirmed the dramatic decrease in the abundance of striped venus clam, Chamelea gallina, and noble pen shell Pinna nobilis, both of which might be attributed to human-induced impacts, habitat degradation and climate change. Official data depicted a gradual reduction of bivalve catches since 1980 and massive degradation of the resources after 2000. As a result, the bivalve fishery was abandoned, having a negative impact on the local socio-economic community. The present study fills in a gap in knowledge for preserving species biodiversity that is critical to the health of the coastal environments. Full article

(This article belongs to the Special Issue Marine Fish and Invertebrate Aquaculture)

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Review

Jump to: Research

14 pages, 3008 KiB

Open AccessReview

Mediterranean Aquaculture and Genetic Pollution: A Review Combined with Data from a Fish Farm Evaluating the Ecological Risks of Finfish Escapes

by Maria V. Alvanou, Konstantinos Gkagkavouzis, Nikoleta Karaiskou, Konstantinos Feidantsis, Athanasios Lattos, Basile Michaelidis, John A. Theodorou, Costas Batargias, Alexandros Triantafyllidis and Ioannis A. Giantsis

J. Mar. Sci. Eng. 2023, 11(7), 1405; https://doi.org/10.3390/jmse11071405 - 12 Jul 2023

Cited by 2 | Viewed by 1273

Abstract

Mediterranean finfish aquaculture is mainly represented by the production of the gilthead sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) growing in marine cage farms. Despite the numerous benefits of fish farming, the ecological risk potentially caused by [...] Read more.

Mediterranean finfish aquaculture is mainly represented by the production of the gilthead sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) growing in marine cage farms. Despite the numerous benefits of fish farming, the ecological risk potentially caused by fish escapes to the wild populations is occasionally high. In the current study, an integrated review of fish escapes is presented regarding S. aurata and D. labrax escapes and their potential effect on the genetic composition of wild populations. The collected data from the literature are combined and discussed along with recorded escapes in a fish farm located in the Aegean Sea, Greece. According to these records, fish escapes present a generally stable rate, ranging between 0 and 2% in each escape event, which occur 5–8 times per year. Although for other farmed fish species worldwide, the ecological risk may be higher, this risk is probably lower in Mediterranean finfish populations, which are characterized by generally low levels of genetic differentiation. Nevertheless, the risk of genetic introgression still exists. Particularly in sea bream and sea bass farming, genetic structure and differentiation in wild populations seem to be unaffected for now. Nevertheless, suitable management measurements would be a useful strategy to avoid future negative effects of fish escapes. These strategies should be focused on further efforts towards recapture program development, reduced escapees’ survival, and proper legislation. Furthermore, more data on escapees’ survival percentage, their migration pathways, and the way these pathways relate to mortality, the type of escape event, and the season of release would be also valuable. Full article

(This article belongs to the Special Issue Marine Fish and Invertebrate Aquaculture)

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18 pages, 2229 KiB

Open AccessFeature PaperReview

Expert Systems for Farmed Fish Disease Diagnosis: An Overview and a Proposal

by Ioannis Hatzilygeroudis, Konstantinos Dimitropoulos, Konstantinos Kovas and John A. Theodorou

J. Mar. Sci. Eng. 2023, 11(5), 1084; https://doi.org/10.3390/jmse11051084 - 21 May 2023

Cited by 1 | Viewed by 2122

Abstract

The expert system approach, although quite old, is still quite effective in scientific areas where experts are required to make diagnoses and predictions. One of those areas is fish disease diagnosis. It is an application domain that currently employs complicated processes, which require [...] Read more.

The expert system approach, although quite old, is still quite effective in scientific areas where experts are required to make diagnoses and predictions. One of those areas is fish disease diagnosis. It is an application domain that currently employs complicated processes, which require high level skills for making accurate diagnoses. On the other hand, complete datasets for full diagnosis to be able to use machine learning techniques are not available. Therefore, in aquaculture, now more than ever, fish farmers do not have the required expertise or equipment to accurately diagnose a fish disease. For that reason, expert systems that can help in the diagnosis, prevention, and treatment of diseases have been developed. In this paper, we attempt to give an overview of the expert system approaches for fish disease diagnosis developed in the last two decades. Based on the analysis of their technical and non-technical characteristics, we propose an expert system architecture and a fish disease diagnosis process aiming at improving the deficiencies of the existing systems. The proposed system can handle all types of fish diseases based on image and non-image data as well as on molecular test results and can provide explanations. The diagnosis process goes through four consecutive levels, where each next level considers an additional category of parameters and provides diagnoses with a higher certainty. Full article

(This article belongs to the Special Issue Marine Fish and Invertebrate Aquaculture)

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19 pages, 1045 KiB

Open AccessReview

Knowledge on the Biological and Fisheries Aspects of the Japanese Sardine, Sardinops melanostictus (Schlegel, 1846)

by Ousmane Sarr, Richard Kindong and Siquan Tian

J. Mar. Sci. Eng. 2021, 9(12), 1403; https://doi.org/10.3390/jmse9121403 - 09 Dec 2021

Cited by 4 | Viewed by 3481

Abstract

Japanese sardine (Sardinops melanostictus) is a significant small pelagic fish and a valuable resource that plays an essential ecological role in the marine ecosystem. It is present in the far Eastern Asian maritime waters, including the Pacific Ocean, Sea of Japan, [...] Read more.

Japanese sardine (Sardinops melanostictus) is a significant small pelagic fish and a valuable resource that plays an essential ecological role in the marine ecosystem. It is present in the far Eastern Asian maritime waters, including the Pacific Ocean, Sea of Japan, and the East China Sea. Encircling nets, particularly purse seines, are the most used fishing equipment to catch this species. Their fishing grounds are located entirely in coastal areas. Japanese sardine catches have shown varying trends over the last five decades, with a high frequency of captures occurring in the 1980s before collapsing in the early 1990s. The economic and ecological importance of this species has prompted much research, which provided additional information about their spawning migration, distribution, fisheries, and biology. This research was mostly undertaken in the Sea of Japan and its adjacent waters spanning in the north Pacific Ocean. Despite all this research and the importance of this species in its habitats and in commercial fisheries, there is a lack of a recent review presenting the status of global fisheries and biological information for this species. This paper summarizes and updates information on the global geographical distribution, biological aspects, trends in catches, stock fluctuations and assessment, and management measures of the Japanese sardine population. This paper also summarizes information related to the influence of environmental factors on the occurrence of this species and also identifies information gaps. Further research directions are also discussed in this work, which may help improve the knowledge of Japanese sardine and establish rational management measures for their conservation. Full article

(This article belongs to the Special Issue Marine Fish and Invertebrate Aquaculture)

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