ICES Journal of Marine Science: Journal du Conseil

Henderson, M E; Mills, K E; Alexander, M A; Barajas, M; Collins, M J; Dzaugis, M; Kircheis, D; Sheehan, T F

doi: 10.1093/icesjms/fsad127pmid: N/A

The Gulf of Maine hosts the southernmost remaining population of North American Atlantic salmon. Despite extensive hatchery supplementation since the late 1800s, and more recent riverine habitat restoration efforts and fishing restrictions, US-origin Atlantic salmon populations continue to decline and have remained at low abundance over recent decades. Climate change has been identified as a critical threat to the future of US Atlantic salmon. In this study, we synthesized available information on how habitats used by Atlantic salmon across all their life stages will be affected by climate change as well as the suitability of future conditions for salmon’s persistence in the region. Maintaining sufficient cool water refugia during increasing summer temperatures in riverine habitats is required for sustaining salmon in the future. Changes in groundwater quantity and temperature, which will depend on future precipitation and temperature, will be critical factors for river temperatures, as will land use and land cover. While Atlantic salmon’s freshwater life stages are heavily documented, the marine phase is relatively less studied. Climate models predict basin-scale changes over the next century, but impacts to salmon are difficult to predict. Furthermore, disparate drivers and differential rates of change between freshwater and marine habitats could present an obstacle to the transition between phases in the future. We have a general understanding of migration patterns and prey preferences but lack a clear picture of how salmon respond to habitat and ecosystem-level changes associated with climate change progression. More research to understand freshwater habitat changes and salmon’s marine spatiotemporal distribution responses will enhance capacities to evaluate future risks and predict impacts of climate change to US-origin Atlantic salmon.

Waller, J; Bartlett, J; Bates, E; Bray, H; Brown, M; Cieri, M; Clark, C; DeVoe, W; Donahue, B; Frechette, D; Glon, H; Hunter, M; Huntsberger, C; Kanwit, K; Ledwin, S; Lewis, B; Peters, R; Reardon, K; Russell, R; Smith, M; Uraneck, C; Watts, R;

Link, J S; Thur, S; Matlock, G; Grasso, M

doi: 10.1093/icesjms/fsad143pmid: N/A

Marine ecosystems face many consequential pressures. Yet, we lack an integrative and predictive capacity to understand how marine ecosystems will respond to the cumulative impacts of these pressures, including climate change. It is not enough to detect responses after the fact; it has become imperative to know in advance where major biological resources or hazards will occur, when they will peak, and how that will impact economic performance. Although forecasts exist for some components of marine ecosystems, these are disparate and suffer from a lack of coordination. There is a need for coordinated, cross-ecosystem scale, integrated, marine ecosystem predictions and synthesis products. The value proposition relative to the blue economy is quite high, positively influencing billions if not trillions of marine sector dollars.

Alizadeh Ashrafi, Tannaz; Hermansen, Øystein; Kvamsdal, Sturla F

doi: 10.1093/icesjms/fsad135pmid: N/A

The benefits of individual vessel quota (IVQ) management in terms of improved harvest strategy and profitability are well recognized, but there is less focus on how different components of a quota portfolio can influence decisions underlying the effort allocation and profit-maximizing behaviour of fishers. Variations in the components of the quota portfolio may create economic incentives that alter the optimal harvest strategy and profitability. Thus, we study the potential impact of different components of quota portfolio on the intra-annual harvest strategy and profitability in two segments of the Norwegian bottom trawl fleet. By developing a vessel-based spatio-temporal bioeconomic framework, we demonstrate and compare adopted harvest strategies and accrued profits for small and large trawl vessels under three scenarios regarding restrictive quotas in codfish fishery. Our analysis confirms that alternations in the components of the quota portfolio influence the spatio-temporal dynamics of the fishing effort for small and large trawl vessels in different ways, probably due to the differences in vessel-specific characteristics. We also demonstrate that the differences in profit between small and large vessels in part depend on the overall size of the quota portfolio. The economies of scale in the trawl industry are being eroded as the shares of higher-priced species in the quota portfolio decreases. The benefits of economies of scale cannot be reaped as trawlers respond to the reduction in profit by redirecting effort from offshore areas of the Arctic to nearshore waters or staying ashore. Likewise, having small quotas of high-priced species reduces the effectiveness of the IVQ system in meeting management objectives, and could in some cases undermine sustainability outcomes. Our results also demonstrate that both the intensity with which fishers react to the fluctuations in market price levels and fishers’ perceptions of location attractiveness are influenced by the components of the quota portfolio.

Wolfe, Kennedy; Desbiens, Amelia A; Pietsch, Emma; Mumby, Peter J

doi: 10.1093/icesjms/fsad136pmid: N/A

Cryptic species and their interactions are challenging to describe owing to the difficulties in observing and sampling their populations. Such methodological hurdles are critical to resolve, especially when important interactions involving poorly described species are detected. The red decorator crab, Schizophrys aspera, is a newfound predator of the corallivorous Pacific crown-of-thorns seastar (CoTS; Acanthaster sp.). We discuss the Indo-Pacific distribution and taxonomy of S. aspera and provide characterization of its cryptic population at sites around Heron Island, Great Barrier Reef, that differ in CoTS densities. Most S. aspera (>95%) were found under coral rubble pieces atop existing rubble, associated with large pieces and chasmic interstices. The three smallest individuals (carapace width: 5–11 mm) were found under rubble overlying sand. Mean density of S. aspera was 0.8 ± 0.2 ind. 100 m−2, which varied among sites. Areas with lower records of CoTS had higher densities of S. aspera (p = 0.002; R2 = 0.25), which justifies evaluation of the distribution and impact of this species in context of CoTS outbreaks. We present a method to survey cryptic decapods on coral reefs, along with microhabitat characteristics to help predict S. aspera on reefs prone to CoTS outbreaks and its capacity to act as a natural top-down control mechanism.

Fisch, N; Shertzer, K; Camp, E; Maunder, M; Ahrens, R

doi: 10.1093/icesjms/fsad138pmid: N/A

Increasingly, mixed-effect fishery stock assessment models are being developed where deviations about functional forms of different processes are modelled as random effects and the extent of variance is estimated internal to the model. Concurrently, sampling variance parameters associated with likelihoods for fitting composition data within fisheries assessments are more often being estimated internal to the model as well. We examine the performance of stock assessment models when multiple process variance and sampling variance terms are simultaneously estimated within assessment models. We specifically examine how assessment performance is affected by the choice of composition likelihood, the degree of overdispersion in composition data, overparameterization, and modelling variation on the wrong process. In doing so, we build a simulation containing overdispersion and correlations in composition data, directional variation in catchability and/or selectivity, and estimation models which include random effects and composition likelihoods with theoretically estimable variances. Results suggest that with standard data available in fisheries assessments, process variance parameters associated with some commonly employed methods and sampling variance parameters can be simultaneously estimated internal to an assessment, and performance greatly improves with increased composition data. Our results also suggest little downside to overparameterization of selectivity and catchability when the true process is not time-varying, which largely agrees with previous research. However, when a process is truly time-varying and the assessment models time-variation on a different process, namely when selectivity is time-varying and instead natural mortality is modelled as potentially time-varying, we find a risk of severe increases in bias and decreases in confidence interval coverage for assessed quantities. This bias and decrease in coverage could, however, be partially mitigated by also modelling time-variation on the correct process.

Veron, Pierre; Rozanski, Romane; Marques, Virginie; Joost, Stéphane; Deschez, Marie Emilie; Trenkel, Verena M; Lorance, Pascal; Valentini, Alice; Polanco F., Andrea; Pellissier, Loïc; Eme, David; Albouy, Camille

doi: 10.1093/icesjms/fsad139pmid: N/A

Environmental DNA (eDNA) metabarcoding is a method to detect taxa from environmental samples. It is increasingly used for marine biodiversity surveys. As it only requires water collection, eDNA metabarcoding is less invasive than scientific trawling and might be more cost effective. Here, we analysed data from both sampling methods applied in the same scientific survey targeting Northeast Atlantic fish in the Bay of Biscay. We compared the methods regarding the distribution of taxonomic, phylogenetic, and functional diversity. We found that eDNA captured more taxonomic and phylogenetic richness than bottom trawling and more functional richness at the local scale. eDNA was less selective than trawling and detected species in local communities spanning larger phylogenetic and functional breadths, especially as it detected large pelagic species that escaped the trawl, even though trawling detected more flat fish. eDNA indicated differences in fish community composition that were comparable to those based on trawling. However, consistency between abundance estimates provided by eDNA metabarcoding and trawl catches was low, even after accounting for allometric scaling in eDNA production. We conclude that eDNA metabarcoding is a promising method that can complement scientific trawling for multi-component biodiversity monitoring based on presence/absence, but not yet for abundance.

Birchenough, S N R

doi: 10.1093/icesjms/fsad142pmid: N/A

The “blue economy” idea promotes the responsible and sustainable use of coastal and marine resources. The need to balance the exploitation and economic use of these resources has moved to the top of the research agenda and management priorities for small island developing states (SIDS). SIDS face unique challenges due to their geographic, economic, and environmental characteristics. While the specific challenges can vary based on the individual SIDS, some common future challenges include (i) climate change and sea-level rise resulting from the increased frequency and intensity of storms and coastal erosion; (ii) natural disasters such as hurricanes, cyclones, tsunamis, and earthquakes, resulting in extensive damage, disruption of essential services, and lead to loss of lives and livelihoods; (iii) lack of sustainable development and economic diversification leading to reliance on few key sectors, such as tourism and agriculture, which are vulnerable to market fluctuations; (iv) energy security and renewable energy transition; as there is dependency on imported fossil fuels for their energy needs, price fluctuations and supply disruptions occurs; (v) biodiversity conservation and marine resource management; they host unique ecosystems and rich biodiversity, including coral reefs, mangroves, and marine species; and (vi) access to finance and technology; there are direct opportunities, for accessing funds to support technology development under sustainable finance projects. This themed article set attracted 14 submissions, 7 of which were accepted for publication. The topics covered fisheries, climate change effects, marine litter, and development of new technologies and finance mechanisms to support the SIDS. Overall, these contributions have emphasized the remarkable role that SIDS play in the protection and management of coastal and marine ecosystems, but also highlighted several needs and key priorities.

Phang, Sui; March, Antaya; Touron-Gardic, Gregoire; Deane, Kieran; Failler, Pierre

doi: 10.1093/icesjms/fsac230pmid: N/A

Caribbean countries face many challenges to effectively implement and benefit from the blue economy. This study synthesized current available information from the literature about the main blue economy activities in the Bahamas, Barbados, Belize, Guyana, Jamaica, Trinidad and Tobago, and Suriname, prior to the COVID-19 pandemic, to highlight their value in the context of blue economic recovery. This timestamp of data provides a point of comparison to understand the vulnerability of blue economy sectors to external shocks. The top performing sectors prior to the pandemic were shipping and tourism, both of which were significant contributors to the GDP. The other sectors (e.g. fisheries, aquaculture, pharmaceuticals, etc.) in some countries were well established and in others, at a minimum, displayed potential for continued development. To valorize the blue economy in a post pandemic recovery, there are three core areas of opportunity: sustainable resource extraction and production; cultivated economic development; and improved ecosystem economic valuations. Harnessing these opportunities will require a transition from a traditional ocean economy towards a coordinated blue economy, including the adoption of effective governance and sustainability principles, improved social, economic, and environmental valuations, and sustainable financing, as well as a more regional coordinated approach to the management of resources.

March, Antaya; Failler, Pierre; Bennett, Michael

doi: 10.1093/icesjms/fsac238pmid: N/A

The paper presents the blue economy development in The Bahamas with an analysis of the conditions for using blue bonds as a financing mechanism. As part of the activities to be pursued for the issuance of a blue bond, the paper provides an identification of investment projects that could be financed through blue bonds. In addition to its blue economy activities, the government seeks to enhance the coastal ecosystems’ resilience and their capacity to reduce the effects of strong climatic events following the Dorian Hurricane in September 2019. In this context, investments in the protection and restoration of ecosystems that increase public goods are therefore needed, especially in the context of the 30 × 30 target. The paper furthermore highlights the key challenges The Bahamas is facing for the development of suitable blue financial mechanisms, including the need for a robust institutional framework to ensure an efficient implementation of a blue financing scheme. By explicitly reflecting on the challenges for a country like the Bahamas, the paper seeks to provide a realistic account of the role and potential of bonds for financing sustainable development in marine environments.