Lawrence Estuary Research Articles

Phylogeography of Neomysis americana (Crustacea, Mysida), focusing on the St. Lawrence system

AbstractSpecies characterized by low dispersal capacities, such as mysids, usually show evidence of genetic differentiation. Many mysids are broadly distributed and often show eurythermal and euryhaline traits. This study aimed to describe intraspecific genetic structure and the phylogeography of Neomysis americana, a key species of estuarine food webs in northwest Atlantic, using the mitochondrial cytochrome c oxidase subunit I gene. We sampled 26 populations across the St. Lawrence system (SLS) and two along the east coast of North America [Penobscot and Chesapeake Bay (CB)]. Sequencing of 420 individuals revealed three divergent (>3%) lineages (LA, LB, LC) across the sampling area suggesting that N. americana represents a cryptic species complex. The distribution of the lineages was geographically structured. LC occurred in the CB only, whereas LA and LB co-occurred along the SLS and Penobscot Bay. This suggests secondary contact after the last glacial maximum. In the SLS the lineage LA dominated the estuarine transition zone and the Gulf of St. Lawrence, whereas the lineage LB was prevalent in the lower St. Lawrence Estuary, potentially due to different eco-physiological preferences. These results might help to define reasonable entities for research and management.

Visual and passive acoustic observations of blue whale trios from two distinct populations

Visual and passive acoustic observations of blue whale trios from two distinct populations

New insight into light-enhanced calcification in mytilid mussels, Mytilus sp., infected with photosynthetic algae Coccomyxa sp.: δ13C value and metabolic carbon record in shells

The posterior shell edge (PSE) of wild mytilid mussels that are highly infected with unicellular photosynthetic green algae Coccomyxa sp. exhibits an extra shell material (ESM). A recently proposed mechanism of ESM formation shows similarity with light-enhanced calcification (LEC), i.e., algae photosynthesis mediates low respiratory CO2 level in shell calcification site (PSE) to promote ESM precipitation. The present study evaluates if infection with algae may affect the δ13C content and metabolic carbon (CM) contribution to shells (PSE) in mussels from the Lower St. Lawrence Estuary, Québec, Canada. Environmental conditions may influence shell δ13C records. To underline possible algae photosynthesis effects, mantle, adductor muscle and shell δ13C are analyzed in infected and non-infected mussels collected from two sites with different salinities, seawater dissolved inorganic carbon (DIC) content, and hydrodynamic regimes. Shell δ13C and tissue δ13C correlate with seawater DIC and salinity. Shell δ13C values are lowest in non-infected mussels, whereas tissues δ13C values show the opposite relationship; in both cases, differences between δ13C values in non-infected and infected mussels are about 0.5‰. The percentage of CM incorporated into shell is higher (ca. 18%) for non-infected mussels than infected mussels (ca. 15%). Literature on the subject suggests that increased δ13C content and decreased %CM in shells of infected mussels must be related to algal photosynthetic activity. Our findings show that shell δ13C records permit the interpretation of ESM formation via LEC.

Feeding ecology of early life stages of striped bass (Morone saxatilis) along an estuarine salinity-turbidity gradient, St. Lawrence Estuary, Canada

Abstract After being extirpated from the St. Lawrence River in the 1960s, striped bass (Morone saxatilis) were reintroduced to the estuary in 2002 and by 2008, they were naturally reproducing. To document the habitat use and feeding ecology of this reintroduced population, we examined the gut contents of 333 larvae and juveniles. Samples were collected in four estuarine habitats in 2014: the upstream freshwater section (UP), the oligohaline (O-ETM) and the mesohaline (M-ETM) estuarine turbidity maximum zones, and the downstream polyhaline section (DOWN). In June, pelagic larvae developed in the UP and the O-ETM, feeding mainly on copepods such as Eurytemora affinis. The O-ETM exhibited better suitable feeding conditions compared to the UP, likely due to the presence of Bosmina sp. as a primary prey. After July, striped bass shifted to larger prey items, consuming mainly dipteran pupa in upstream littoral habitats and gammarids and mysids in downstream habitats. In the early summer, the UP provided a high-quality nursery habitat and as the season progressed, the smallest juveniles dispersed downstream and improved their feeding success by exploiting a new feeding niche. This observation suggests that being distributed throughout the estuary may increase the potential survival of striped bass early life stages.

Pattern of Anguillicoloides crassus infestation in the St. Lawrence River watershed

The non-native swim bladder nematode Anguillicoloides crassus was first documented in wild American eel (Anguilla rostrata) in South Carolina in 1996, and has since spread through rivers and estuaries along the east coast of the United States and Canada. American eel in Canada are a species of conservation concern, primarily due to a severe decline in recruitment within the St. Lawrence River watershed. We report the first occurrence of A. crassus in American eel in the St. Lawrence River watershed in 2010. Prevalence of A. crassus infection remained low through 2014, but has since increased to approximately 30% over the past 3 years. Infection intensity has also increased from only a single nematode up to 2013 to an average of 6.5 nematodes per infected eel in 2018. In outmigrating silver-stage eels sampled in the St. Lawrence estuary, the first occurrence of A. crassus was noted in 2015 and prevalence has fluctuated from a low 0.2% in 2015 to a high of 3.6% in 2017. In 2018, A. crassus was first identified in an eel recruiting to the upper St. Lawrence River. A. crassus was likely inadvertently introduced to the St. Lawrence River watershed during a conservation stocking research project in which glass-stage eels from infected areas were translocated to the region to supplement natural recruitment. It is not clear at this time what harm this additional threat will pose to an already declining contingent of this panmictic species.

Early growth, mortality, and partial migration of striped bass (Morone saxatilis) larvae and juveniles in the St. Lawrence estuary, Canada

AbstractAfter being extirpated from the St. Lawrence Estuary (SLE), striped bass (Morone saxatilis) were reintroduced in 2002, and by 2008 they were naturally reproducing. The increase of this reintroduced population prompted the need to document its nursery habitats utilization, which contribute to species recruitment. We analysed mortality-dispersion rates and the growth of larvae and juveniles in relation to their occurrence and migration patterns. From June to September 2014, we collected striped bass distributed in four estuarine habitats: the upstream freshwater section (UP), the oligohaline (O-ETM) and the mesohaline (M-ETM) estuarine turbidity maximum zone, and the downstream polyhaline section (DOWN). Based on otolith microstructure and microchemistry, 305 back-calculated growth and 36 migration trajectories have been reconstructed. The UP and the O-ETM provided optimal conditions wherein which larvae and juveniles exhibited fastest growth. In the SLE, we emphasized the co-existence of a freshwater resident contingent and two migrant contingents to the M-ETM and DOWN. We propose that migrants adopt an adaptive migration behaviour to avoid suboptimal conditions and strong intraspecific competition from resident in the upstream habitats. The potential advantage of a downstream migration later in the season might be an adaptative strategy to promote their survival during the early life stages.

Origin of spherulitic and cone-in-cone concretions in Cambro-Ordovician black shales, St Lawrence Estuary, Quebec, Canada

AbstractSpherulitic concretions are very rare among carbonate concretions that generally consist of micritic carbonate. The occurrence of spherulitic concretions in Cambro-Ordovician black shales of unknown stratigraphic age on a mid-channel island in the St Lawrence Estuary in Quebec is a new example in addition to only three hitherto reported occurrences of spherulitic carbonate concretions. Their origin is still poorly understood. These concretions occur in close association with, and show various transitions to, cone-in-cone structure. The spherules, measuring 0.5 to 12 mm in diameter, consist of intergrown fine fibres of ferroan calcite and quartzine, pointing to the formation of the concretions below the sulfate-reduction zone. A phenomenological theory of spherulitic crystallization relates the thickness δ of an impurity-rich layer in front of impurity-rejecting growing crystals to the impurity-diffusion coefficient D and the growth velocity G of the crystal by δ = D/G. In spherulite-forming environments, extremely small values of δ (in the order of <10−4 cm) in conjunction with cellulation lead to spherulitic fibre growth. The theory of spherulitic crystallization is here applied to sedimentary deposits for the first time. The intimate association of calcite and quartzine in the concretions requires a chemical change from alkaline to acidic conditions, which occurs below the carbonate-reduction zone owing to the dissolution of sponge spicules or radiolarians. The transition from spherulite to the silica-free cone-in-cone structure occurs when the silica reservoir that acted as an impurity is exhausted in the crystallization process.

Associations between organohalogen exposure and thyroid- and steroid-related gene responses in St. Lawrence Estuary belugas and minke whales

Elevated concentrations of persistent organic pollutants (POPs) and emerging halogenated flame retardants (HFRs) have been reported in tissues of the endangered St. Lawrence Estuary (Canada) beluga population as well as in minke whales visiting that same feeding area. This study examined the linkages between blubber concentrations of POPs and emerging HFRs, and transcription in skin of genes involved in the regulation of thyroid and steroid axes in belugas and minke whales from the St. Lawrence Estuary. In belugas, concentrations of PCBs, OCs and hexabromobenzene (HBB) were positively correlated with the transcription of thyroid- and/or steroid-related genes, while Dec-604 CB concentrations were negatively associated with the transcription of glucocorticoid and thyroid genes. In minke whales, PBDE concentrations changed positively with Esrβ transcript levels and HBB concentrations negatively with Nr3c1 transcripts. Present results suggest that several biological functions including reproduction and energetic metabolism may represent potential targets for organohalogens in these whales.

Recent distribution, inventories and temporal trends of suspended particulate matter in the St. Lawrence Estuary, Canada

Suspended particulate matter (SPM) is considered to play important biogeochemical roles in aquatic systems, particularly in estuaries, and the assessment of their temporal trends is essential in the current period of climate change. Concentrations of SPM and particulate inorganic matter (PIM) in the St. Lawrence Estuary (SLE), downstream of the maximum turbidity zone (MTZ), were measured at 21 stations during four time periods, related to hydrological or biological events, between 2014 and 2016. SPM concentrations decreased seaward with no lateral difference observed. At the deepest stations, SPM vertical profiles followed a typical ‘C’ shape whereas PIM content increased from surface to bottom. The inventories of SPM in the study area varied from 1.29 ×106 tons during the period of low river runoff to 2.14 ×106 tons during the spring freshet. On average, 80% of SPM was made of PIM. The amount of PIM (SPM) entering the Lower SLE during the 8 to 9 ice-free months corresponded roughly to its inventory in the study area suggesting that PIM (SPM) stays in the water column for several months before being removed by sedimentation. Our results support the hypothesis that most SPM is retained in the MTZ during the summer and released with drifting ice during the winter–spring periods. Strong relationships were observed between water discharges at Quebec City and SPM (PIM) inventories in the study area (R2>0.94). The variability of SPM (PIM) inventories, estimated from water discharge proxy, was highest during the period of spring freshet and lowest during the period of low river runoff. When corrected for water discharges, a significant decrease in SPM and PIM inventories was observed over the last 15 years.

Contrasting effects of acidification and warming on dimethylsulfide concentrations during a temperate estuarine fall bloom mesocosm experiment

Abstract. The effects of ocean acidification and warming on the concentrations of dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) were investigated during a mesocosm experiment in the Lower St. Lawrence Estuary (LSLE) in the fall of 2014. Twelve mesocosms covering a range of pHT (pH on the total hydrogen ion concentration scale) from 8.0 to 7.2, corresponding to a range of CO2 partial pressures (pCO2) from 440 to 2900 µatm, at two temperatures (in situ and +5 ∘C; 10 and 15 ∘C) were monitored during 13 days. All mesocosms were characterized by the rapid development of a diatom bloom dominated by Skeletonema costatum, followed by its decline upon the exhaustion of nitrate and silicic acid. Neither the acidification nor the warming resulted in a significant impact on the abundance of bacteria over the experiment. However, warming the water by 5 ∘C resulted in a significant increase in the average bacterial production (BP) in all 15 ∘C mesocosms as compared to 10 ∘C, with no detectable effect of pCO2 on BP. Variations in total DMSP (DMSPt = particulate + dissolved DMSP) concentrations tracked the development of the bloom, although the rise in DMSPt persisted for a few days after the peaks in chlorophyll a. Average concentrations of DMSPt were not affected by acidification or warming. Initially low concentrations of DMS (<1 nmol L−1) increased to reach peak values ranging from 30 to 130 nmol L−1 towards the end of the experiment. Increasing the pCO2 reduced the averaged DMS concentrations by 66 % and 69 % at 10 and 15 ∘C, respectively, over the duration of the experiment. On the other hand, a 5 ∘C warming increased DMS concentrations by an average of 240 % as compared to in situ temperature, resulting in a positive offset of the adverse pCO2 impact. Significant positive correlations found between bacterial production and concentrations of DMS throughout our experiment point towards temperature-associated enhancement of bacterial DMSP metabolism as a likely driver of the mitigating effect of warming on the negative impact of acidification on the net production of DMS in the LSLE and potentially the global ocean.

The Speciation and Mobility of Mn and Fe in Estuarine Sediments

Dissolved and solid-phase speciation of Mn and Fe was measured in the porewaters of sediments recovered from three sites in the Greater St. Lawrence Estuary: the Saguenay Fjord, the Lower St. Lawrence Estuary (LSLE) and the Gulf of St. Lawrence (GSL). At all sites and most depths, metal organic ligand complexes (Mn(III)–L and Fe(III)–L) dominated the sedimentary porewater speciation, making up to 100% of the total dissolved Mn or Fe. We propose that these complexes play a previously underestimated role in maintaining oxidized soluble metal species in sedimentary systems and in stabilizing organic matter in the form of soluble metal–organic complexes. In the fjord porewaters, strong (log KCOND > 13.2) and weak (log KCOND < 13.2) Mn(III)–L complexes were detected, whereas only weak Mn(III)–L complexes were detected at the pelagic and hemipelagic sites of the GSL and LSLE, respectively. At the fjord site, Mn(III)–L complexes were kinetically stabilized against reduction by Fe(II), even when Fe(II) concentrations were as high as 57 μM. Only dissolved Mn(II) was released from the sediments to overlying waters, suggesting that Mn(III) may be preferentially oxidized by sedimentary microbes at or near the sediment–water interface. We calculated the dissolved Mn(II) fluxes from the sediments to the overlying waters to be 0.24 µmol cm−2 year−1 at the pelagic site (GSL), 11 µmol cm−2 year−1 at the hemipelagic site (LSLE) and 2.0 µmol cm−2 year−1 in the fjord. The higher benthic flux in the LSLE reflects the lower oxygen concentrations (dO2) of the bottom waters and sediments at this site, which favor the reductive dissolution of Mn oxides as well as the decrease in the oxidation rate of dissolved Mn(II) diffusing through the oxic layer of the sediment and its release to the overlying water.

Concentrations of reactive Mn(III)-L and MnO2 in estuarine and marine waters determined using spectrophotometry and the leuco base, leucoberbelin blue

In terms of its oxidative strength, the MnO2/Mn2+ couple is one of the strongest in the aquatic environment. The intermediate oxidation state, manganese(III), is stabilized by a range of organic ligands (Mn(III)-L) and some of these complexes are also strong oxidants or reductants. Here, we present improved methods for quantifying soluble reactive oxidized manganese(III) and particulate reactive oxidized manganese at ultra-low concentrations; the respective detection limits are 6.7 nM and 7 pM (100-cm spectrophotometric path length) and 260 nM and 2.6 nM (1-cm path length). The methods involve a simple, specific, spectrophotometric technique using a water-soluble leuco base (leucoberbelin blue; LBB). LBB is oxidized by manganese through a hydrogen atom transfer reaction forming a colored complex that is stoichiometrically related to the oxidation state of the manganese, either Mn(III)-L or manganese(III,IV) oxides (MnOx). At the concentration of LBB used in this study, nitrite may be a minor interference, so we provide concentration ranges over which it interferes and suggest potential strategies to mitigate the interference. Unlike previous methods devised to quantify Mn(III)-L, which use ligand exchange reactions, the LBB oxidation requires an electron and therefore needs to physically contact manganese(III) for inner-sphere electron transfer to occur. The method for measuring soluble Mn(III)-L was evaluated in the laboratory, and LBB was found to be oxidized by an extensive suite of weak Mn(III)-L complexes, as it is by MnOx, but could not react with or reacted very slowly with strong Mn(III)-L complexes. According to the molecular structures of the Mn(III)-L complexes tested, LBB can also be used to qualitatively assess the binding strength of Mn(III)-L complexes based on metal-chelate structural considerations. The assays for soluble Mn(III)-L (membrane filtered) and particulate manganese oxides (trapped by membrane filters) were applied to the well-oxygenated estuarine waters of the Saguenay Fjord, a major tributary of the Lower St. Lawrence Estuary, and to Western North Atlantic oceanic waters, off the continental shelf, where there is an oxygen minimum zone (< 67% O2 saturation). The methods applied can be used in the field or onboard ships and provide important new insights into oxidized manganese speciation.

Multihazard simulation for coastal flood mapping: Bathtub versus numerical modelling in an open estuary, Eastern Canada

Coastlines along the St. Lawrence Estuary and Gulf, Eastern Canada, are under increasing risk of flooding due to sea level rise and sea ice shrinking. Efficient and validated regional‐scale coastal flood mapping approaches that include storm surges and waves are hence required to better prepare for the increased hazard. This paper compares and validates two different flood mapping methods: numerical flood simulations using XBeach and bathtub mapping based on total water levels, forced with multihazard scenarios of compound wave and water level events. XBeach is validated with hydrodynamic measurements. Simulations of a historical storm event are performed and validated against observed flood data over a ~25 km long coastline using multiple fit metrics. XBeach and the bathtub method correctly predict flooded areas (66 and 78%, respectively), but the latter overpredicts the flood extent by 36%. XBeach is a slightly more robust flood mapping approach with a fit of 51% against 48% for the bathtub maps. Deeper floodwater by ~0.5 m is expected with the bathtub approach, and more buildings are vulnerable to a 100‐year flood level. For coastal management at regional‐scale, despite similar flood extents with both flood mapping approaches, results suggest that numerical simulation with XBeach outperforms bathtub flood mapping.

Communities of Phytoplankton Viruses across the Transition Zone of the St. Lawrence Estuary.

The St. Lawrence hydrographic system includes freshwater, brackish, and marine habitats, and is the largest waterway in North America by volume. The food-webs in these habitats are ultimately dependent on phytoplankton. Viral lysis is believed to be responsible for a major part of phytoplankton mortality. To better understand their role, we characterized the diversity and distribution of two viral taxa infecting phytoplankton: the picornaviruses and phycodnaviruses. Our study focused on the estuary transition zone, which is an important nursery for invertebrates and fishes. Both viral taxa were investigated by PCR amplification of conserved molecular markers and next-generation sequencing at six sites, ranging from freshwater to marine. Our results revealed few shared viral phylotypes between saltwater and freshwater sites. Salinity appeared to be the primary determinant of viral community composition. Moreover, our analysis indicated that the viruses identified in this region of the St. Lawrence diverge from classified viruses and homologous published environmental virotypes. These results suggest that DNA and RNA viruses infecting phytoplankton are likely active in the estuary transition zone, and that this region harbors its own unique viral assemblages.

Greenhouse gas flux with reflooding of a drained salt marsh soil.

Salt marshes are highly effective carbon (C) sinks and bury more C per square meter annually than any other ecosystem. Reclamation and anthropogenic impacts, however, have resulted in extensive losses of salt marshes. Carbon credits can be generated and sold by restoring marshes, but only if C sequestration and net reductions in greenhouse gases (GHG) are reliably quantified. Restored marshes, however, may exhibit different patterns of GHG emissions than natural marshes and it is possible that they could temporarily become sources of N2O even in the usually N-limited estuarine environment. Research on short-term GHG flux following salt marsh restoration is limited to studies of two restored marshes which examined GHG flux more than six months after the return of tidal flooding. Here we report on a laboratory experiment in which soil cores collected from a drained agricultural marsh on the St. Lawrence Estuary were flooded with estuary water. Gas flux measurements immediately after flooding revealed small increases in N2O and CH4, but a large decline in CO2 yielding, from a climatic perspective, a net cooling effect over the observation period. In addition to restoring the land’s capacity to sequester C once a marsh develops, returning tidal flooding thus appears to have the added benefit of stemming large ongoing C losses. With more than 400 km2 of undeveloped dykeland, Eastern Canada is well positioned to restore large sections of marsh and contribute to reducing atmospheric CO2 concentrations.

Distribution of desferrioxamine-B-extractable soluble manganese(III) and particulate MnO2 in the St. Lawrence Estuary, Canada

Soluble organically-complexed manganese(III) (Mn(III)-L) is an intermediate species in the manganese cycle. The reactivity of the complex(es) depends on the abundance and nature of the ligand(s), as well as its physicochemical environment. Currently, the strength of Mn(III)-L complexes is assessed by their ability to react either directly with a porphyrin complex, using the kinetics of its competitive ligand exchange reactions, or after being reduced to manganese(II). We present a new three-step technique that quantifies part of the Mn(III)-L pool which may represent a bioavailable and reactive fraction of the complexes. This technique relies on 1) ligand exchange of the dissolved complexes in a filtered field sample with the siderophore desferrioxamine-B (DFOB), 2) chromatographic separation and concentration of manganese(III)-DFOB from the aqueous matrix, and 3) quantification of the naturally ligated manganese(III) that was outcompeted by DFOB (Mn(III)-LDFOB) at low concentrations by flow injection UV-Vis spectrophotometry. The formation of an extractable Mn(III)-LDFOB complex provides an operationally-defined benchmark by which to assess biological interactions and better understand the cycling of manganese(III) in the environment. The technique, with a detection limit of 0.09 nM, was applied to water samples collected in the St. Lawrence Estuary (SLE) and adjacent Saguenay Fjord in Canada. Mn(III)-LDFOB was ubiquitous at our study sites, but its concentration was low relative to total dissolved manganese (dMnT) and particulate MnO2. Spatial variations of the dMnT speciation within the Saguenay Fjord suggest that Mn(III)-L forms from the reduction of MnO2. Likewise, variations of the dMnT speciation along a dissolved oxygen gradient in the SLE leads us to believe that Mn(III)-LDFOB likely represents a fraction of the total Mn(III)-L that cycles more readily in estuarine and marine systems.

Pseudomonas laurentiana sp. nov., an Mn(III)-oxidizing Bacterium Isolated from the St. Lawrence Estuary

Pseudomonas laurentiana sp. nov., an Mn(III)-oxidizing Bacterium Isolated from the St. Lawrence Estuary

Intestinal polycyclic aromatic hydrocarbon-DNA adducts in a population of beluga whales with high levels of gastrointestinal cancers.

Carcinogenic polycyclic aromatic hydrocarbons (PAHs) were disposed directly into the Saguenay River of the St. Lawrence Estuary (SLE) by local aluminum smelters (Quebec, Canada) for 50 years (1926-1976). PAHs in the river sediments are likely etiologically related to gastrointestinal epithelial cancers observed in 7% of 156 mature (>19-year old) adult beluga found dead along the shorelines. Because DNA adduct formation provides a critical link between exposure and cancer induction, and because PAH-DNA adducts are chemically stable, we hypothesized that SLE beluga intestine would contain PAH-DNA adducts. Using an antiserum specific for DNA modified with several carcinogenic PAHs, we stained sections of paraffin-embedded intestine from 51 SLE beluga (0-63 years), 4 Cook Inlet (CI) Alaska beluga (0-26 years), and 20 beluga (0-46 years) living in Arctic areas (Eastern Beaufort Sea, Eastern Chukchi Sea, Point Lay Alaska) and aquaria, all with low PAH contamination. Stained sections showed nuclear light-to-dark pink color indicating the presence of PAH-DNA adducts concentrated in intestinal crypt epithelial lining cells. Scoring of whole tissue sections revealed higher values for the 51 SLE beluga, compared with the 20 Arctic and aquarium beluga (P = 0.003). The H-scoring system, applied to coded individual photomicrographs, confirmed that SLE beluga and CI beluga had levels of intestinal PAH-DNA adducts significantly higher than Arctic and aquarium beluga (P = 0.003 and 0.02, respectively). Furthermore, high levels of intestinal PAH-DNA adducts in four SLE beluga with gastrointestinal cancers, considered as a group, support a link of causality between PAH exposure and intestinal cancer in SLE beluga. Environ. Mol. Mutagen. 60:29-41, 2019. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

Toxoplasma gondii infection in stranded St. Lawrence Estuary beluga Delphinapterus leucas in Quebec, Canada.

The St. Lawrence Estuary (SLE) beluga Delphinapterus leucas in Quebec, Canada, is endangered due to intensive hunting in the 19th and 20th centuries and subsequent anthropogenic contamination and human activities in the region. Infectious disease is a primary cause of death in this population. The protozoan parasite Toxoplasma gondii is reported in numerous marine mammal species, including beluga. In the present study, 55 tissue samples (heart and brain) collected from 34 stranded SLE beluga were analysed by PCR followed by DNA sequencing and restriction fragment length polymorphism analysis (RFLP) to determine the PCR prevalence and genotypes of T. gondii in these beluga. Of 34 beluga tested, 44% were positive for T. gondii by PCR, with males having a higher prevalence of infection than females and with more infected neonates and juveniles than adults. Molecular analyses indicated that all T. gondii infecting stranded SLE beluga grouped into genotype II, which predominates in humans. While our results indicate that a high prevalence of stranded beluga are PCR-positive for T. gondii infection, very few deaths are attributed to toxoplasmosis based on published necropsy results. Toxoplasma gondii can cause a range of diseases, including neurological deficits, and more data are needed to investigate this parasite's effect on population recovery.

A voluntary conservation agreement reduces the risks of lethal collisions between ships and whales in the St. Lawrence Estuary (Québec, Canada): From co-construction to monitoring compliance and assessing effectiveness.

Lethal collisions with ships are limiting the recovery of several at-risk whale species worldwide. In the St. Lawrence Estuary (Quebec, Canada), the endangered blue whale and of special concern fin whale are among the migratory species subject to collisions with large ships. In 2011, a working group composed of representatives from the maritime industry, the government, non-governmental organizations, and academia was created to explore solutions to mitigate ship-whale collisions in the St. Lawrence Estuary. Adopting an adaptive risk management framework, the working group took advantage of the best available scientific data and tools to co-construct realistic collision mitigation options and evaluate their likely benefits for whale conservation and costs for the industry. In 2013, the working group recommended the implementation of voluntary measures to mitigate collision risks, consisting of a slow-down area, a no-go area, and a caution area; a recommended route was added in 2014. Along with the voluntary framework, the working group agreed to continuously monitor compliance with and assess effectiveness of these mitigation measures. After the fourth year of implementation, voluntary measures showed encouraging results, with a reduction of up to 40% of lethal collision risks with fin whales in the highest density area. This reduction in risk is mainly related to ship speed reduction in the slow-down area from 14.1 ± 2.6 knots in 2012 to 11.3 ± 1.7 knots since 2014. The presence of a mandatory pilotage area overlapping with the slow-down area was instrumental to facilitate communication about the mitigation measures, with the pilotage corporation sitting as a regular member of the working group. This resulted in significantly slower speeds in the slow-down area for ships with a pilot from the pilotage corporation onboard compared to those without (-0.8 knots, p-value < 0.001). It is also likely to explain the weaker compliance of the maritime industry with the no-go area located outside of the mandatory pilotage area. Other factors of success include: the continuous dedication of the government to a voluntary and transparent participatory process; the use of available data, tools and institutions; the presence of an environmental certification program representative in the working group; and the adoption by consensus of an adaptive risk management approach. The traditional regulatory approach to conservation is often blamed for its focus on deterring negative behaviors, doing nothing to encourage and reward positive ones. In agreement with other case studies, the benefits of the voluntary measures implemented in the St. Lawrence Estuary include the pro-active commitment from the industry (which is likely to reduce conflicts with regulators), the greater flexibility and freedom that allowed to come up with cost-effective and tailored-made mitigation measures, and the fast achievement of conservation gains. More importantly perhaps, the human and working capital built throughout the concertation process have the potential to be a fundamental cornerstone in dealing with more complex issues such as the chronically increasing level of underwater noise in whale habitats.