• Energy Research

The mechanistic approach and the potential predictive power of Dynamic Energy Budget (DEB) models are making this modelling framework increasingly popular in aquaculture management. The potential to mechanistically simulate life-history traits of a species in a changing environment has already been applied to many commercial species, including the New Zealand Greenshell™ mussel Perna canaliculus. However, the previous P. canaliculus model parameterisation, available in the Add-my-Pet (AmP) collection, has been carried out on a limited data set. We used data obtained through targeted laboratory experiments and combined it with literature data, to derive a new version of the model which included information on additional processes – such as feeding, respiration, and reproduction – and life stages: larvae and adults. We compared the performance of the previous version of the model, termed AmP-2018 with the revised model (AmP-2024), to predict the whole life-cycle of the mussel and life-history traits of interest in the context of aquaculture. The entry completeness score (0−10), which provides an indication of data quality and variety as well as model comprehensiveness and applicability, increased dramatically from 2.5 to 5.5, suggesting P. canaliculus is now the most comprehensively DEB-parameterised bivalve, while the model increased in accuracy of the predictions. The endeavour highlights several conclusions: (i) reliable temperature response data are required to establish the thermal response curve; the presence/absence of this type of data should be taken into account when assessing the completeness of a model and its applicability to predict thermal responses of a species; (ii) species-specific parameter values are preferred over general (higher taxonomic level) specific values, e.g. for tissue organics and water content, as they increase the accuracy of predictions; (iii) data pertaining to laboratory trials and to wild populations both need to be taken into account when calibrating a mechanistic model at a species level; and (iv) calculating energy requirements of any organism, including bivalves, requires data on characteristics and products often overlooked in an experimental setting. We discuss the new version of the model in the context of the knowledge and predictive power potentially gained by adding more information and data during model calibration. The obtained results and conclusions are especially relevant in aquaculture, whether for commercial rearing of mussels, or their potential application in multitrophic aquaculture systems.

Species invasion is an important cause of global biodiversity decline and is often mediated by shifts in environmental conditions such as climate change. To investigate this relationship, a mechanistic Dynamic Energy Budget model (DEB) approach was used to predict how climate change may affect spread of the invasive mussel Mytilopsis sallei, by predicting variation in the total reproductive output of the mussel under different scenarios. To achieve this, the DEB model was forced with present-day satellite data of sea surface temperature (SST) and chlorophyll-a concentration (Chl-a), and SST under two warming RCP scenarios and decreasing current Chl-a levels, to predict future responses. Under both warming scenarios, the DEB model predicted the reproductive output of M. sallei would enhance range extension of the mussel, especially in regions south of the Yangtze River when future declines in Chl-a were reduced by less than 10%, whereas egg production was inhibited when Chl-a decreased by 20-30%. The decrease in SST in the Yangtze River may, however, be a natural barrier to the northward expansion of M. sallei, with colder temperatures resulting in a strong decrease in egg production. Although the invasion path of M. sallei may be inhibited northwards by the Yangtze River, larger geographic regions south of the Yangtze River run the risk of invasion, with subsequent negative impacts on aquaculture through competition for food with farmed bivalves and damaging aquaculture facilities. Using a DEB model approach to characterise the life history traits of M. sallei, therefore, revealed the importance of food availability and temperature on the reproductive output of this mussel and allowed evaluation of the invasion risk for specific regions. DEB is, therefore, a powerful predictive tool for risk management of already established invasive populations and to identify regions with a high potential invasion risk.

Global warming, through increasing temperatures, may facilitate the spread and proliferation of outbreak-forming species which may find favourable substrate conditions on artificial aquaculture structures. The presence of stinging organisms (cnidarian hydroids) in the facilities fouling community are a source of pollution that can cause critical problems when in-situ underwater cleaning processes are performed. Multiple stressor experiments were carried out to investigate the cumulative effect on farmed mussels' functional traits when exposed to realistic stressful conditions, including presence of harmful cnidarian cells and environmental conditions of increasing temperature and short-term hypoxia. Exposure to combined stressors significantly altered mussels' performance, causing metabolic depression and low filtering activity, potentially delaying, or inhibiting their recovery ability and ultimately jeopardizing organisms' fitness. Further research on the stressors properties and occurrence is needed to obtain more realistic responses from organisms to minimize climate change impacts and increase ecosystem and marine economic activities resilience to multiple stressors.

Aquaculture industry represents a continuously growing sector playing a fundamental role in pursuing United Nation's goals. Increasing sea-surface temperatures, the growth of encrusting species and current cage cleaning practices proved to affect the productivity of commercial species. Here, through a Dynamic Energy Budget application under two different IPCC scenarios, we investigate the long-term effects of Pennaria disticha fragments' on Mytilus galloprovincialis' functional traits as a result of cage cleaning practices. While Climate-Change did not exert a marked effect on mussels' Life-History traits, the simulated effect of cage cleanings highlighted a positive effect on total weight, fecundity and time to commercial size. West-Mediterranean emerged as the most affected sector, with Malta, Montenegro, Morocco, Syria, Tunisia and Turkey between the top-affected countries. These outcomes confirm the reliability of a DEB-approach in projecting at different spatial and temporal scale eco-physiological results, avoiding the limitation of short-term studies and the difficulties of long-term ones.

Climate change is evolving so fast that the related adverse effects on the environment are becoming noticeable. Thus, there is an urgent need to explore and understand the effects generated by multiple extreme climatic events (MECEs) on marine ecosystem functioning and the services provided. Accordingly, we combined long-term in-situ empirical observations in the Mediterranean Sea with a mesocosm manipulation to investigate the concurrence of increasing temperature and hypoxia events. By focussing on a foundation mussel species, we were able to detect several cascade events triggered by a mass mortality event caused by stressful temperature and oxygen conditions, and resulting in a loss of ecosystem services. The measured rates of chlorophyll-a, carbohydrates, proteins and lipids - in both particulate and sedimentary organic matter - were used as proxies of ecosystem functioning during pre- and post- disturbance events (MECEs). In the past, MECEs were crucial for individual performance, mussel population dynamics and biomass. Their effect propagated along the ecological hierarchy negatively affecting the associated community and ecosystem. Our results suggest that the protection and/or restoration of coastal areas requires careful consideration of ecosystem functioning. SIGNIFICANCE STATEMENT: Our decadal time-series recorded by a near-term ecological forecasting network of thermal sensor allowed us to record and monitor multiple extreme climatic events (MECEs; heat wave and hypoxia events), warning on the environmental change recorded on a pond system. By integrating observational and manipulative approaches, we showed how a MECE triggered cascade events, from individual-based impaired functioning up to biodiversity loss (community composition and structure changes). Our results emphasize the key role played by a foundation species in driving ecosystem functioning, and the synergistic effects of climatic drivers acting simultaneously.