Shellfish Resources Research Articles

SOCIOECONOMIC MODEL OF SHELLFISH RESOURCES IN SEMBILANG NATIONAL PARK BANYUASIN REGENCY SOUTH SUMATRA

The Sembilang National Park area has blood cockle (Anadara granosa) resources. Catching blood cockles is done traditionally, namely using hands at low tide. To maintain shellfish resources, it is necessary to analyze the factors that influence socioeconomic catches. The aim of this research is to calculate and analyze the factors that influence and determine the best socio-economic model for shellfish resources in Sembilang National Park. This research was carried out in February 2022 in the waters of Sembilang National Park. Determining the number of respondents and collecting data in this study used the incidental sampling method and data collection was carried out by interviews using questionnaires. Model assumption testing includes normality test, linearity test, multicollinearity test, heteroscedasticity test and autocorrelation test. Best fit model uses a multiple linear regression equation approach with the backward analysis regression method, namely Y = -1456.315 + 0.116X1 + 1.514 X2 + 2.547 X3 - 12.558 X 7 + ε. Factors that influence the number of catches of shellfish resources in Sembilang National Park, Banyuasin Regency are the selling price of shellfish, operating costs, income and number of dependents. Keywords: Shellfish resources, best fit model, Sembilang National Park, Socioeconomics.

Making Unique Handicrafts from Shells in Lake Bird's Nest Village

Making unique handicrafts using shells in Sarang Burung Danau Village aims to process marine waste which can be used as a creative medium for PKK mothers, increasing creativity, soft skills and an entrepreneurial spirit from an early age. This activity is focused on making unique craft items using shells as the main material, stimulating creativity and economic empowerment in the village. This initiative involves collaboration between students from various universities involved in KKN Kebangsaan 2023 activities and the local community, emphasizing the exchange of knowledge, skills and cultural experiences. The method for this service activity is to conduct a workshop which directs the training participants to practice directly making handicrafts by following the work steps. Through workshops and hands-on activities, participants explore innovative craft-making techniques while using natural resources responsibly. With this type of qualitative research, the results of this activity are a source of pride for the community, creating economic opportunities and preserving traditional skills. The products produced include pencil cases, wall hangings, mirror frames and miniature birds. The aim of this research is to encourage environmental awareness by emphasizing the sustainable use of shellfish resources. The implication of this research is that it can encourage the use of local resources, in this case shellfish, more effectively. This can help reduce pressure on the environment and promote sustainable practices in the use of natural resources.

Optimization of a Novel Tyrosinase Inhibitory Peptide from Atrina pectinata Mantle and Its Molecular Inhibitory Mechanism.

In order to realize the multi-level utilization of marine shellfish resources and to develop the potential biological activity of processing by-products of Atrina pectinata, gelatin was extracted from the mantle and the potential whitening effect of its enzymatic peptides was explored. Taking tyrosinase inhibitory activity as the evaluation index, the enzyme hydrolysate process was optimized by response-surface methodology, and the optimal enzyme hydrolysate conditions were as follows: pH 5.82, 238 min enzyme hydrolysate time, and temperature of 54.5 °C. Under these conditions, the tyrosinase inhibition activity of Atrina pectinata mantle gelatin peptide (APGP) was 88.6% (IC50 of 3.268 ± 0.048 mg/mL). The peptides obtained from the identification were separated by ultrafiltration and LC-MS/MS, and then four new peptides were screened by molecular docking, among which the peptide Tyr-Tyr-Pro (YYP) had the strongest inhibitory effect on tyrosinase with an IC50 value of 1.764 ± 0.025 mM. The molecular-docking results indicated that hydrogen bonding is the main driving force for the interaction of the peptide YYP with tyrosinase. From the Lineweaver-Burk analysis, it could be concluded that YYP is inhibitory to tyrosinase and exhibits a mixed mechanism of inhibition. These results suggest that YYP could be widely used as a tyrosinase inhibitor in whitening foods and pharmaceuticals.

Middle Holocene Oyster Shells and the Shifting Role of History in Ecological Restoration: How a Dynamic Past Informs Shellfish Ecosystem Reconstruction at an Australian Urban Estuary

Abstract At Western Australia's Swan-Canning Estuary, extensive subfossil shellfish assemblages of Middle Holocene origin were largely destroyed through dredging for cement production in the first half of the twentieth century. This case-study of an extractive industry driving shellfish ecosystem decline builds on existing historical studies of commercial over-harvesting of oysters, and historical and paleo-ecological investigations of sustainable, long-term indigenous oyster harvests, presenting an important new perspective on global shellfish ecosystem decline and the enduring cultural value of shellfish resources by revealing processes of cross-cultural knowledge transfer, unfolding environmental understanding and extensive environmental change across Western Australia's post-European settlement history. We explore these histories in detail for the first time, before considering their relevance to a shellfish ecosystem reconstruction initiative currently underway at this major Australian urban estuary.

First data on the effect of Aluminium intake in Chamelea gallina of exploited stocks in the Southern Adriatic Sea (Central Mediterranean Sea)

The striped venus clam Chamelea gallina is an important shellfish resource in coastal area of Mediterranean Basin, playing a fundamental role in the ecosystems. In the last two decades there has been a reduction in the stocks of this bivalve with several mortality events along Adriatic Sea due to pollutants. Aiming to evaluate the effects on clams of the anthropogenic increase of some metals in the sea, we focused on aluminium. In particular, we tested whether Al could affect mucus secretion, since mucins are involved in protection from pathogens and toxicants and transport of alimentary particles and pseudofeces. Aluminium was administered in the form of aluminium chloride at concentrations of 25, 50 and 200 μM. Histochemical and lectin-histochemical - analyses were used to evaluate in situ qualitative and quantitative variation of the muciparous secretions produced by both the gills and foot epithelia. Treatments resulted in quali-quantitative alterations in the secretions of both gills and foot epithelia, in particular reduction of glycosylation resulting in a general decrease of acidic residuals and of mannosylated, glycosaminylated and fucosylated chains. This can result in a decrease of acidity and viscosity of mucus and thus it could affect its functionality and the survival of the animals.

Modelling coastal upwelling off NW Iberian Peninsula: New insights on the fate of phytoplankton blooms

The northwestern coast of the Iberian Peninsula is a region characterized by pronounced hydrologic and biogeochemical activity, resulting in important fish and shellfish resources whose exploitation has a strong local socioeconomic impact. This high biological diversity is strongly dependent on coastal upwelling induced by favourable winds, which presents seasonal variability. This motivates the present study, which aims to understand the relation between local circulation, hydrography and Chl-a concentration under summer upwelling events of different intensities and clarify their effects in the region. To achieve this purpose, a coupled physical-biological model was developed and validated for the northwestern coast of the Iberian Peninsula, based on the use of MOHID modelling system and the application of a nested domains methodology. Comparison of predictions with observations demonstrated the model's accuracy in reproducing the physical and biogeochemical properties of the study region, both at the surface and along the water column. The study of different summer upwelling events shows that the local phytoplankton patterns are dependent on the characteristics of the event. Results show that under high upwelling favourable winds, a surface southwestward flow and an equatorward flow through the water column develop near the coast, inducing offshore advection of nutrient and phytoplankton-rich waters. Otherwise, under light upwelling favourable winds, surface currents are weak, a poleward flow develops, and phytoplankton is retained near the coast.

Dinophysis acuminata or Dinophysis acuta: What Makes the Difference in Highly Stratified Fjords?

Dinophysis acuminata and D. acuta, which follows it seasonally, are the main producers of lipophilic toxins in temperate coastal waters, including Southern Chile. Strains of the two species differ in their toxin profiles and impacts on shellfish resources. D. acuta is considered the major cause of diarrhetic shellfish poisoning (DSP) outbreaks in Southern Chile, but there is uncertainty about the toxicity of D. acuminata, and little information on microscale oceanographic conditions promoting their blooms. During the austral summer of 2020, intensive sampling was carried out in two northern Patagonian fjords, Puyuhuapi (PUY) and Pitipalena (PIT), sharing D. acuminata dominance and D. acuta near detection levels. Dinophysistoxin 1 (DTX 1) and pectenotoxin 2 (PTX 2) were present in all net tow samples but OA was not detected. Although differing in hydrodynamics and sampling dates, D. acuminata shared behavioural traits in the two fjords: cell maxima (>103 cells L-1) in the interface (S ~ 21) between the estuarine freshwater (EFW)) and saline water (ESW) layers; and phased-cell division (µ = 0.3-0.4 d-1) peaking after dawn, and abundance of ciliate prey. Niche analysis (Outlying Mean Index, OMI) of D. acuta with a high marginality and much lower tolerance than D. acuminata indicated an unfavourable physical environment for D. acuta (bloom failure). Comparison of toxin profiles and Dinophysis niches in three contrasting years in PUY-2020 (D. acuminata bloom), 2018 (exceptional bloom of D. acuta), and 2019 (bloom co-occurrence of the two species)-shed light on the vertical gradients which promote each species. The presence of FW (S < 11) and thermal inversion may be used to provide short-term forecasts of no risk of D. acuta blooms and OA occurrence, but D. acuminata associated with DTX 1 pose a risk of DSP events in North Patagonian fjords.

Sowing Machine for Scallop Seedling in Bottom-culture

The scallop is among the most important shellfish resource and is a proven candidate for aquaculture in many countries. In China, the scallop is generally bottom culture and artificial seeding. Artificial seeding on scallops is a difficult process with low production efficiency, high labor intensity, excessive cost low profit, and high rate of mortality and damage. In this paper, a sowing machine is developed for the bottom-sowing culture of the scallop. It consists of a transmission module, sows slide module, and buoyancy module. The structure and working mechanism of this machine are presented and analyzed in detail. The tests of experiments were conducted as well with the development machine. Through the simulation analysis of flow field of bottom-sown machine. The results show that the vortex area below the platform makes the scallop seedlings seedlings spread more evenly. In addition, the boat-shaped fairing at the head of the platform effectively reduces the water flow rate inside the platform, allowing the scallop seedlings to successfully leave the platform through the grille at the bottom of the platform after sowing. The control group efficiency is 26.67%; however, the optimized group efficiency average value is 57.97%. The cost of bottom sowing 1t scallop seedling was reduced from 1260 RMB to 124.4 RMB. It is proven that the design of the machine is feasible.

Ecological value of mariculture shellfish resources in China: Assessment and management

Under the background of global climate change and carbon reduction commitment, it is of great significance to study the ecological value of mariculture shellfish resources. China is the largest country in terms of mariculture shellfish. In this study, the ecological value of mariculture shellfish in China was dynamically evaluated after determining the shellfish ecological value composition and the value calculation coefficients. On this basis, the dynamic characteristics of the mariculture shellfish ecological values during 2010–2019 were revealed, as well as the economic problems and reasons behind. The study results indicated that the average ecological value of mariculture shellfish in China showed an overall upward trend. The core values of mariculture shellfish are carbon sequestration and water purification, which displayed an increasing trend. The habitat value of mariculture shellfish showed a significant downward trend because of the reduction of aquaculture area and the increase of aquaculture density. Additionally, the increase in the heavy metal enrichment value was due to the rising production of mariculture shellfish and the rising price of processing heavy metals in China. Therefore, innovative management policies were proposed including introducing a third-party independent consultant, building a carbon-sink shellfish demonstration zone, improving a carbon-sink market transaction mechanism, establishing a nitrogen credit market, and controlling the full-cycle management of mariculture shellfish based on biotechnology and blockchain technology. It was hoped to promote the healthy development of the mariculture shellfish industry and make China's contribution to the world's carbon emission reduction.

Assessing the carbon sink capacity of coastal mariculture shellfish resources in China from 1981–2020

The ocean has considerable potential to function as a carbon sink, absorbing anthropogenic CO2 and buffering the effects of climate change. How the culture of shellfish can be used to increase the ocean carbon sink warrants evaluation. We analyze the production and carbon sink capacity of six important mariculture shellfish species (oyster, ark clam, mussel, scallop, clam, and razor clam) in nine coastal provinces of China from 1981–2020 using quality assessment and logarithmic mean Divisia index (LMDI) decomposition methods. Over this time period both cultured shellfish production and its contribution to the carbon sink generally increase, averaging approximately 600,000 t annually over the last four decades. Both the annual production and carbon sink capacity of China’s mariculture shellfish industry vary geographically. The total annual tonnage (scale) of cultured shellfish, and to a lesser extent, coastal shellfish species composition (structure) influence carbon sink capacity, and affect China’s plans to achieve “dual carbon goals.” Combining historical analysis and the LMDI method, we propose a scheme that optimally and more sustainably manages China’s culture of shellfish.

A review on shellfish polysaccharides: Extraction, characterization and amelioration of metabolic syndrome.

Shellfish are diverse, widely distributed organisms that are a rich source of biological resources. Polysaccharides are an important components in shellfish, hence a great deal of attention has been directed at isolation and characterization of shellfish polysaccharides because of their numerous health benefits. Differences in shellfish species, habits, and environment result in the diversity of the structure and composition of polysaccharides. Thus, shellfish polysaccharides possess special biological activities. Studies have shown that shellfish polysaccharides exert biological activities, including antioxidant, antitumor, immune-regulation, hypolipidemic, antihypertensive, and antihyperglycemic effects, and are widely used in cosmetics, health products, and medicine. This review spotlights the extraction and purification methods of shellfish polysaccharides and analyses their structures, biological activities and conformational relationships; discusses the regulatory mechanism of shellfish polysaccharides on hyperlipidemia, hypertension, and hyperglycemia caused by lipid metabolism disorders; and summarizes its alleviation of lipid metabolism-related diseases. This review provides a reference for the in-depth development and utilization of shellfish polysaccharides as a functional food to regulate lipid metabolism-related diseases. To achieve high value utilization of marine shellfish resources while actively promoting the development of marine biological industry and health industry.

A cryptic species of Ensis (Bivalvia: Pharidae) from the southeastern Pacific coast revealed by geometric morphometric methods

A new cryptic species of Ensis from the Pacific coast of South America based on geometric morphometrics is revealed. Ensis macha (Molina, 1782) is one of the most important shellfish resources in South America. It was historically reported from San Matías Gulf, Argentina in the Atlantic Ocean to the Peruvian coast in the Pacific. A recent study analysed the intraspecific variation of this species along its distribution range and the genetic results indicated the presence of cryptic diversity. Two evolutionary clades were found: a southern clade (from cold-temperate waters) and a northern clade (from warm-temperate waters). New results based on geometric morphometrics supported the description of Ensis loboi n. sp. for the northern clade. The southern clade retains the name due to type locality of E. macha in Chiloé, Chile. The description of Ensis loboi n. sp. for the southeastern Pacific Ocean has important implications for future studies focused on fisheries management and biogeographical radiation of the group.

Length-weight relationships and condition factor of the main species of fish caught on the Bandama River (Ivory Coast)

The Ivory Coast has economically and ecologically important rivers that contain various fish and shellfish resources. Thus, the present study aims to assess the length-weight relationships and the condition factor of fish stocks in selected sites on the Bandama River from July 2013 to June 2014. The growth pattern of each species was identified at the using a regression model calculated for the length-weight relationship. The condition factor (K) was analyzed for each species. There were six species of fish (Chrysichthys nigrodigitatus, Synodontis bastiani, Synodontis schall, Marcusenius senegalensis, Coptodon zillii and Labeo coubie). The length-weight relationship determined for the above six species showed a negative allometric growth pattern (b&lt;3) indicating faster length increase relative to weight for five of them. They are Chrysichthys nigrodigitatus, Coptodon zillii, Synodontis bastiani, Synodontis schall and Marcusenius senegalensis, Only the species Labeo coubie presented a positive allometric growth (b&gt;3) showing that this species put on weight faster than it grows. The habitat qualities of the majority of fish species were therefore in optimal environmental conditions. The results of the present study constitute a reference, which taken into account would be useful for the implementation of a plan for the sustainable management of fishery resources in Ivory Coast.

Reproductive cycle of the golden carpet shell (Polititapes aureus) in the Ria Formosa lagoon (southern Portugal)

AbstractThe present study described the gametogenesis and assessed the pattern of energy storage throughout the reproductive cycle of the golden carpet shell (Polititapes aureus) from the Ria Formosa lagoon (southern Portugal). Monthly sampling was performed for two years (March 2016–February 2018) and the study was based on gonad histology, complemented by the estimation of the mean gonadal index, body condition index and biochemical composition. The species’ reproductive cycle presented a seasonal pattern, with a resting period mainly between October and January and gametogenesis beginning around February–March. The spawning season of P. aureus was shorter in 2016 (June–September) than in 2017 (May–October). Furthermore, ripe individuals were very scarce (1.3%) in 2017 compared with the previous year (11.4%). Mean gonadal index (GI) reflected the species’ reproductive cycle and the body condition index (CI) and biochemical composition of the individuals exhibited high variation between years. Regarding the biochemical composition, proteins ranged between 190.6 and 595.2 μg mg−1, glycogen from 5.7 to 102.6 μg mg−1 and total lipids between 31.6 and 80.7 μg mg−1. The reproduction of P. aureus was strongly influenced by fluctuations in both seawater temperature and chlorophyll a, as reflected through the temporal variation in the gonadal cycle, condition index and biochemical composition. Overall, the information gathered in this study is valuable to propose scientifically based harvesting management measures for the long-term sustainable exploitation of this shellfish resource, further reinforcing the importance of implementing adaptive fishery management strategies to cope with global climate change.

Twenty-Five Years of Domoic Acid Monitoring in Galicia (NW Spain): Spatial, Temporal and Interspecific Variations.

Prevalence, impact on shellfish resources and interspecific, spatial, and temporal variabilities of domoic acid (DA) in bivalves from Galicia (NW Spain) have been studied based on more than 25 years of monitoring data. The maximum prevalence (samples in which DA was detected) (100%) and incidence (samples with DA levels above the regulatory limit) (97.4%) were recorded in Pecten maximus, and the minimum ones in Mytilus galloprovincialis (12.6 and 1.1%, respectively). The maximum DA concentrations were 663.9 mg kg−1 in P. maximus and 316 mg kg−1 in Venerupis corrugata. After excluding scallop P. maximus data, DA was found (prevalence) in 13.3% of bivalve samples, with 1.3% being over the regulatory limit. In general, the prevalence of this toxin decreased towards the North but not the magnitude of its episodes. The seasonal distribution was characterized by two maxima, in spring and autumn, with the later decreasing in intensity towards the north. DA levels decreased slightly over the studied period, although this decreasing trend was not linear. A cyclic pattern was observed in the interannual variability, with cycles of 4 and 11 years. Intoxication and detoxification rates were slower than those expected from laboratory experiments, suggesting the supply of DA during these phases plays an important role.

Diversity, Length-Weight Relations, and Condition Factor of Sea Cucumbers in Three Coastal Areas Along the Southern Coast of Sri Lanka: A Case Study

Economically and ecologically important ecosystems that consist of diverse finfish and shellfish resources are found along the southern coast of Sri Lanka. Thus, the current study intends in assessing the species diversity, length-weight (L-W) relationships, and condition factor of sea cucumber stocks in selected coastal sites of southern Sri Lanka. The diversity of sea cucumber species was surveyed using the systematic sampling technique in three selected sites (Bandaramulla, Mirissa, and Weligama) during February-December 2019. The growth pattern of each species was identified using a least-squares regression model computed for length-weight relationships. Fulton’s condition factor (K) was analysed for each species. There were four common sea cucumber species (Holothuria atra - Lolly Fish, Bohadschia marmorata - White Thread fish, Actinipyga miliaris- Deep Water Blackfish, and Thelenota ananas- Prickly Redfish) in study sites, while Holothuria atra and Bohadschia marmorata were recorded as the most abundant species. The length-weight relationship derived for the above four species exhibited a negative allometric growth pattern (“b” &lt; “3”), indicating faster length increment compared to weight. The habitat qualities of all sea cucumber species were in optimum environmental condition. Our findings would benefit as baseline data for implementing sustainable management practices of sea cucumber resources.

Using Multiple Ecological Models to Inform Environmental Decision-Making

Coastal ecosystems are experiencing degradation from compound impacts of climate change and multiple anthropogenic disturbances. These pressures often act synergistically and complicate designing effective conservation measures; consequently, large-scale coastal restoration actions become a wicked problem. The purpose of this study was to use two different food web models in a coordinated manner to inform resource managers in their assessment of the ecological effects of a large-scale marsh restoration project. A team was formed that included the model developers and outside scientists, who were asked to use available model results of the calibrated simulations of an Ecopath with Ecosim (EwE) model and a Comprehensive Aquatic Systems Model (CASM), both designed to describe the structure and energetics of the Barataria Bay, Louisiana, United States food web. Both models offer somewhat different depictions of the predator-prey and competitive interactions of species within the food web, and how environmental conditions affect the species biomass pools and energetics. Collectively, the team evaluated the strengths of each model and derived a common set of indicator variables from model outputs that provided information on the structure and energy flow of the simulated food web. Considering the different modeling structures and calibration approaches, indicators were interpreted within and between models. Use of both models enabled a robust determination that: (1) Detritus plays a vital role in the energetics of the system; (2) The food web responds to spring high flow seasons by increasing productivity through specific, dominant pathways; (3) The trophic pyramid is truncated; (4) Compared to other estuaries, this system has redundant pathways for energy transfer. These findings indicate that the food web appears to be resilient to disturbance because of a detritus energy reserve, most consumer biomass consists of low trophic level, high turnover species, and redundant energy pathways exist. This information provides context to decision-makers for assessing possible basin-scale impacts on fish and shellfish resources of a proposed large-scale restoration project. The use of multiple models in a coordinated but not overly constrained way, as demonstrated here, provides a significant step toward co-production of knowledge for use in resource management decisions.

Population growth model of Anadara granosa based on correlation between dimension of shell with the weight at the water environment of Sunda Strait

Exploitation of shellfish resources can affect its growth which can be seen from changes in the size of the shell dimensions including length, width and height. The study was conducted to determine the relationship between the dimensions of the shell with its total weight as a description of growth patterns, and to determine the environmental factors that affect shell growth. Descriptive method with direct observation technique was carried out at 3 observation stations in the Sunda Strait waters. Data were analyzed using power regression, while the correlation of environmental parameters were analyzed using PCA. The results show that the correlation between the dimensions of the shell and the total weight of the shell is allometric negative (b <3), which is an unbalanced growth between the dimensions of the shell and the weight of the shell, so that the shell growth pattern is indicated by the increase in width, length and height that was faster than the body weight. The parameters that affects the dimensions of the shell and weight are NH3-N, NO2-N, BOD, salinity, depth, TOM, brightness, Pb, Cd, Hg and temperature.

Effects of triclosan exposure on the energy budget of Ruditapes philippinarum and R. decussatus under climate change scenarios.

We built a simulation model based on Dynamic Energy Budget theory (DEB) to assess the growth and reproductive potential of the native European clam Ruditapes decussatus and the introduced Manila clam Ruditapes philippinarum under current temperature and pH conditions in a Portuguese estuary and under those forecasted for the end of the 21st c. The climate change scenario RCP8.5 predicts temperature increase of 3°C and a pH decrease of 0.4units. The model was run under additional conditions of exposure to the emerging contaminant triclosan (TCS) and in the absence of this compound. The parameters of the DEB model were calibrated with the results of laboratory experiments complemented with data from the literature available for these two important commercial shellfish resources. For each species and experimental condition (eight combinations), we used data from the experiments to produce estimates for the key parameters controlling food intake flux, assimilation flux, somatic maintenance flux and energy at the initial simulation time. The results showed that the growth and reproductive potential of both species would be compromised under future climate conditions, but the effect of TCS exposure had a higher impact on the energy budget than forecasted temperature and pH variations. The egg production of R. philippinarum was projected to suffer a more marked reduction with exposure to TCS, regardless of the climatic factor, while the native R. decussatus appeared more resilient to environmental causes of stress. The results suggest a likely decrease in the rates of expansion of the introduced R. philippinarum in European waters, and negative effects on fisheries and aquaculture production of exposure to emerging contaminants (e.g., TCS) and climate change.

Cold-water shellfish as harvestable resources and important ecosystem players

Abstract The symposium, Shellfish—Resources and Invaders of the North, took place 5–7 November 2019 in Tromsø, Norway. Approximately 110 participants presented and discussed 60 talks and 25 posters. Of these, ten articles are published in this symposium issue. The goal of this symposium was to discuss the role of shellfish, both as harvestable resources and as important ecosystem players in northern hemisphere cold marine environments. To provide perspective for the symposium, the development of four major crustacean fisheries (northern shrimp, snow crab, Homarus, Norway lobster) are reviewed. Our review showed that landings of all these fisheries are still in a state of flux due to inherent population dynamics, fishing, and climate change. The talks and posters covered a broad range of state-of-the-art bioecological knowledge and present challenges in the assessment and management of the most ecologically and/or commercially important cold-water shellfish species belonging to the phyla Arthropoda, Mollusca, and Echinodermata. Various alternative harvesting and management techniques were presented along with perspectives for shellfish aquaculture. Methods and models for stock assessment were thoroughly covered as well as the ecological role of shellfish, their population dynamics, new insights into their biology and genetics, and their changing distribution and significance as invasive species.