South Coast Of Newfoundland Research Articles

Landscape, demographic, and dispersal parameters influence the spread and establishment of an aquatic biological invasion

AbstractHuman‐mediated species introductions are contributing to the biotic homogenization of global flora and fauna. Despite extensive research, we lack simple methods of predicting how and where an introduced species will spread and establish, particularly in species with complex life histories in aquatic ecosystems. We predict that spread can be modeled simply using the characteristics of the invading population, specifically species growth rate and dispersal capacity. In addition, we predict that the establishment of introduced species should be explained by the characteristics of the receiving ecosystem. Using the brown trout (Salmo trutta) invasion on the Island of Newfoundland as a case study, we fit and test a reaction–diffusion model with brown trout population data collected from the literature. Next, we use statistical models to assess the influence of a suite of abiotic (conductivity, pH, turbidity, calcium), biotic (Atlantic salmon occurrence), and landscape (watershed relief, watershed area, distance to original introduction) variables on brown trout establishment (i.e., presence–absence) patterns. We find that observed coastal spread in Newfoundland is slow (~4.4 km/year), and that it lies on the lower end of the range of predictions made by the reaction–diffusion model parameterized based on the estimates of growth rate and movement from the literature (predicted spread range 1.4 to 92 km/year). Also, we did not find evidence for a relationship between abiotic or biotic variables and brown trout establishment. However, we did observe that landscape variables of the distance to trout introduction point and estuary area may explain establishment patterns along the south coast of Newfoundland. Our results suggest the importance of using population‐specific parameterization and the need to integrate regional landscape factors that are generally applicable across biological invasions (e.g., distance to introduction), and those that are more specific to the ecology of the invader (e.g., estuary area). Our study contextualizes the mechanisms that contribute to a slow invasion by an aquatic species with a complex life history and reveals that future studies need to integrate a variety of methods to elucidate the processes governing invasions.

The complex relationship between weight and length of Atlantic cod off the south coast of Newfoundland

The relationship between the length and weight of fish is used to assess their growth and condition. This relationship is often assumed to be the same spatially and temporally. However, variability in the weight–length relationship can occur, which provides important information about stock productivity. We developed a spatiotemporal model for the weight–length relationship that is useful for predictions in un-sampled areas. We applied the model to survey data for Atlantic cod off the southern coast of Newfoundland, Canada. We found that weight-at-length was higher inshore, oscillated over time, was below average in recent years, declined during late-January to early-June especially for intermediate sized cod, and that the temporal oscillations were correlated with several local environmental time series. Finally, the model estimated a decrease in the allometric coefficient for intermediate sized cod (40–80 cm), indicating that those cod may be experiencing additional feeding deficiencies. Spatiotemporal variation in the weight-at-length relationship should be accounted for in the stock assessment process when fishery catch numbers are derived from tonnes landed and when estimating stock and fishery weights-at-age.

DSS-OSM: An Integrated Decision Support System for Offshore Oil Spill Management

The marine ecosystem, human health and social economy are always severely impacted once an offshore oil spill event has occurred. Thus, the management of oil spills is of importance but is difficult due to constraints from a number of dynamic and interactive processes under uncertain conditions. An integrated decision support system is significantly helpful for offshore oil spill management, but it is yet to be developed. Therefore, this study aims at developing an integrated decision support system for supporting offshore oil spill management (DSS-OSM). The DSS-OSM was developed with the integration of a Monte Carlo simulation, artificial neural network and simulation-optimization coupling approach to provide timely and effective decision support to offshore oil spill vulnerability analysis, response technology screening and response devices/equipment allocation. In addition, the uncertainties and their interactions were also analyzed throughout the modeling of the DSS-OSM. Finally, an offshore oil spill management case study was conducted on the south coast of Newfoundland, Canada, demonstrating the feasibility of the developed DSS-OSM.

Atlantic Salmon (Salmo salar) Cage-Site Distribution, Behavior, and Physiology During a Newfoundland Heat Wave.

Background: Climate change is leading to increased water temperatures and reduced oxygen levels at sea-cage sites, and this is a challenge that the Atlantic salmon aquaculture industry must adapt to it if it needs to grow sustainably. However, to do this, the industry must better understand how sea-cage conditions influence the physiology and behavior of the fish.Method: We fitted ~2.5 kg Atlantic salmon on the south coast of Newfoundland with Star-Oddi milli-HRT ACT and Milli-TD data loggers (data storage tags, DSTs) in the summer of 2019 that allowed us to simultaneously record the fish's 3D acceleration (i.e., activity/behavior), electrocardiograms (and thus, heart rate and heart rate variability), depth, and temperature from early July to mid-October.Results: Over the course of the summer/fall, surface water temperatures went from ~10–12 to 18–19.5°C, and then fell to 8°C. The data provide valuable information on how cage-site conditions affected the salmon and their determining factors. For example, although the fish typically selected a temperature of 14–18°C when available (i.e., this is their preferred temperature in culture), and thus were found deeper in the cage as surface water temperatures peaked, they continued to use the full range of depths available during the warmest part of the summer. The depth occupied by the fish and heart rate were greater during the day, but the latter effect was not temperature-related. Finally, while the fish generally swam at 0.4–1.0 body lengths per second (25–60 cm s−1), their activity and the proportion of time spent using non-steady swimming (i.e., burst-and-coast swimming) increased when feeding was stopped at high temperatures.Conclusion: Data storage tags that record multiple parameters are an effective tool to understand how cage-site conditions and management influence salmon (fish) behavior, physiology, and welfare in culture, and can even be used to provide fine-scale mapping of environmental conditions. The data collected here, and that in recent publications, strongly suggest that pathogen (biotic) challenges in combination with high temperatures, not high temperatures + moderate hypoxia (~70% air saturation) by themselves, are the biggest climate-related challenge facing the salmon aquaculture industry outside of Tasmania.

A tracking study of farmed Atlantic Salmon released from marine aquaculture sites located in the Fortune Bay area of Newfoundland and Labrador (Canada) to inform on sea recapture programs as a mitigation strategy

In this study, we build on previous findings and simulate a salmon fall escape from two aquaculture sites located in a small cove representative of site locations in the South coast of Newfoundland (Canada). Under the previously established premise that recapture should be initiated almost immediately, the study was designed to focus on three main questions: 1) What is the amount of time fish spend in the small bay where they were released? 2) Are the adjacent small enclosed bays with aquaculture sites visited and for how long? 3) Are the depths where fish are detected conducive to their potential recapture? We measured fish movement (n = 60) during 17 days post-release. Results confirm quick responses required for any sea recapture effort to be successful knowing that the feasibility of immediate action following escapes remains logistically challenging. Our findings suggest that quickly targeting the direct site vicinity (within 2 days) as well as any adjacent coves (within 4 days) should be a priority in bays with similar configurations as Fortune Bay. The presence of aquaculture sites in production in these coves is likely a factor influencing the fish movement patterns but this needs to be confirmed by other trials. Fish were detected at depths >10 m indicating that gill nets of appropriate size and/or angling should be used.

Measurement of Aquaculture Chemotherapeutants in Flocculent Matter Collected at a Hard-Bottom Dominated Finfish Site on the South Coast of Newfoundland (Canada) After 2 Years of Fallow

The expansion of aquaculture is resulting in sites being installed over a diversity of substrate types, leading to different potential chemotherapeutant degradation scenarios. There is little to no information on the biodegradation and/or persistence of chemotherapeutants at hard-bottom dominated aquaculture sites having little natural sediment. In this study, we measured organic matter (OM) content and concentrations of chemicals linked to finfish aquaculture activities (trace elements, antibiotics and parasiticides) in flocculent matter samples collected close to cages at a site fallowed for two years and at an active site, the latter being indicative of flocculent chemical signature during production. Our results show persistence of flocculent matter after two years of fallow. The chemical signature of the samples confirms that Cu, Zn, Ca and P, present around fish cages, are direct markers of aquaculture wastes. Persistence of two pyrethroids, one avermectin, and one antibiotic in grab samples show a potentially lasting association between these chemicals and the OM from fish feed and wastes, even after two years. Overall, the concentrations measured do not indicate a direct lethal toxicity on marine organisms (as per studies described in literature) except for Zn. Nevertheless, the long-term persistence of a flocculent mixture rich in chemicals and the lack of information on sublethal and synergistic effects on hard-bottom communities calls for caution and additional studies.

Surficial sediment failures due to the 1929 Grand Banks Earthquake, St Pierre Slope

Abstract A M w 7.2 earthquake centred beneath the upper Laurentian Fan of the SW Newfoundland continental slope triggered a damaging turbidity current and tsunami on 18 November 1929. The turbidity current broke telecommunication cables, and the tsunami killed 28 people and caused major infrastructure damage along the south coast of Newfoundland. Both events are believed to have been derived from sediment mass failure as a result of the earthquake. This study aims to identify the volume and kinematics of the 1929 slope failure in order to understand the geohazard potential of this style of sediment failure. Ultra-high-resolution seismic reflection and multibeam swath bathymetry data are used to determine: (1) the dimension of the failure area; (2) the thickness and volume of failed sediment; (3) fault patterns and displacements; and (4) styles of sediment failure. The total failure area at St Pierre Slope is estimated to be 5200 km 2 , recognized by escarpments, debris fields and eroded zones on the seafloor. Escarpments are typically 20–100 m high, suggesting failed sediment consisted of this uppermost portion of the sediment column. Landslide deposits consist mostly of debris flows with evidence of translational, retrogressive sliding in deeper water (>1700 m) and evidence of instantaneous sediment failure along fault scarps in shallower water (730–1300 m). Two failure mechanisms therefore seem to be involved in the 1929 submarine landslide: faulting and translation. The main surficial sediment failure concentrated along the deep-water escarpments consisted of widely distributed, translational, retrogressive failure that liquefied to become a debris flow and rapidly evolved into a massive channelized turbidity current. Although most of the surficial failures occurred at these deeper head scarps, their deep-water location and retrogressive nature make them an unlikely main contributor to the tsunami generation. The localized fault scarps in shallower water are a more likely candidate for the generation of the tsunami, but further research is needed in order to address the characteristics of these fault scarps.

A zero percent plastic ingestion rate by silver hake (Merluccius bilinearis) from the south coast of Newfoundland, Canada

Silver hake, (Merluccius bilinearis), contributes significant biomass to Northwest Atlantic ecosystems. The incidence of plastic ingestion for 134 individuals collected from Newfoundland, Canada was examined through visual examination of gastrointestinal contents and Raman spectrometry. We found a frequency of occurrence of ingestion of 0%. Through a comprehensive literature review of globally published fish ingestion studies, we found our value to be consistent with 41% (n = 100) of all reported fish ingestion rates. We could not statistically compare silver hake results to other species due to low sample sizes in other studies (less than n = 20) and a lack of standardized sampling methods. We recommend that further studies should 1) continue to report 0% plastic ingestion rates and 2) should describe location and species-specific traits that may contribute to 0% ingestion rates, particularly in locations where fish consumption has cultural and economic significance.

Early life traits of farm and wild Atlantic salmon Salmo salar and first generation hybrids in the south coast of Newfoundland.

This study examined fertilization rates, survival and early life-trait differences of pure farm, wild and first generation (F1) hybrid origin embryos after crossing farm and wild Atlantic salmon Salmo salar. Results show that despite a trend towards higher in vitro fertilization success for wild females, differences in fertilization success in river water are not significantly different among crosses. In a hatchery environment, wild females' progeny (pure wild and hybrids with wild maternal parent) hatched 7-11 days earlier than pure farm crosses and hybrids with farm maternal parents. In addition, pure wild progeny had higher total lengths (LT ) at hatch than pure farm crosses and hybrids. Directions in trait differences need to be tested in a river environment, but results clearly show the maternal influence on early stages beyond egg-size differences. Differences in LT were no longer significant at 70 days post hatch (shortly after the onset of exogenous feeding) showing the need to investigate later developmental stages to better assess somatic growth disparities due to genetic differences. Higher mortality rates of the most likely hybrids (farm female × wild male hybrids) at egg and fry stages and their delayed hatch suggest that these F1 hybrids might be less likely to survive the early larval stages than wild stocks.

Industrial aquaculture and the politics of resignation

While neoliberalism is often framed as a withdrawal of the state, many scholars have noted that what is occurring is not so much a withdrawal, as a repositioning. Although many social services and regulatory functions once provided by government agencies have indeed been eroded, there has been a simultaneous channeling of new resources into other arenas, in an effort to create conditions in which private corporations can operate more profitably. This, however, often places the state in a contradictory position, simultaneously serving as regulator, investor, and development advocate for the private sector. This can become especially problematic in moments of ecological crisis when decisive and unbiased responses are needed. This paper explores these dynamics through an examination of the cycles of growth and crisis that have characterized the aquaculture industry on the south coast of Newfoundland since the late 1970s as well as the ongoing attempts by aquaculture advocates to characterize industrial-scale fish farming as a sustainable industry, despite evidence to the contrary.

Trophic analyses of opportunistic polychaetes (Ophryotrocha cyclops) at salmonid aquaculture sites

A new species of dorvilleid polychaete,Ophryotrocha cyclops, has been observed on the rocky seafloor underneath deep salmonid aquaculture sites on the south coast of Newfoundland, Canada. The distribution of these opportunistic worms is likely related to organic matter accumulation on the seafloor, and this species may have a role in remediation processes. To better understand the functional role ofO. cyclopsat aquaculture sites, it is important to know what they feed upon. Here, stable isotope analyses (δ13C, δ15N and δ34S) and trace element analyses were performed on dorvilleids and their potential food sources at three aquaculture sites. Stable isotope analyses revealed spatial and temporal variation in the isotopic carbon signature ofO. cyclops, highlighting possible differences in the food sources of individual dorvilleids within and between sites. The isotopic composition of dorvilleids was closest to that of fish pellets; the presence of abundant lipid droplets in gut epithelial cells ofO. cyclopssuggests the assimilation of fish pellet-derived lipids. Trace element analysis indicated thatO. cyclopsdoes not concentrate the aquaculture tracers Zn or Cu to a large extent. However, concentrations of sulphur were high inO. cyclopscompared with other sources. Taken together, results show thatO. cyclopsmost likely consume both fish pellets and flocculent matter-associated bacteria. As such, they are involved in sulphur cycling and fish pellet degradation at aquaculture sites.

Survival of farmed, wild and first generation hybrid Atlantic salmon (Salmo salar Linnaeus, 1758) to low temperatures following seawater transfer

In Newfoundland and Labrador, all farmed Atlantic salmon originate from the Saint John River strain (New Brunswick), raising the question of impacts of escapees on wild, genetically distinct stocks. While adverse genetic changes due to hybridization between farmed and wild salmon might not be manifested until the second generation (F2), the existence of F2 or later generations depends ultimately on the survival of F1 hybrids. After smoltification, cold spring seawater temperatures (1.5–5°C) such as those observed on the south coast of Newfoundland can be problematic to salmon as the combination of abrupt seawater exposure and cold temperature is known to overwhelm osmoregulatory mechanisms. No significant differences in total mortality were observed among wild, farmed and F1 hybrids after transfer to seawater and exposure to very cold temperatures. Our findings suggest that farmed salmon and F1 hybrids resulting from crossing wild salmon and St John River farm salmon are as likely to survive seawater migration in cold temperatures as their wild counterparts.

Occurrence of the parasitic copepod Ergasilus labracis on Threespine Sticklebacks from the south coast of Newfoundland.

A study conducted from August to October 2013 surveyed Threespine Sticklebacks Gasterosteus aculeatus (n = 822) for the presence of parasitic copepods in the vicinity of large sea-cage salmonid farms in Bay d'Espoir, Newfoundland. The majority of parasitic copepods surveyed were Ergasilus labracis (n = 4,684). Other parasitic copepods observed on Threespine Sticklebacks during the survey included chalimus-stage Lepeophtheirus spp. (n = 3), adult Argulus alosae (n = 2), and a single Thersitina gasterostei. This represents a new host record for E. labracis. The copepods were present on fish collected in a broad range of temperatures (6.9-17.7°C) and salinities (10.2-30.2 [Practical Salinity Scale]). The parasitic copepods were most commonly found on larger hosts estimated to be age 1 or older. Surprisingly, the highest infestations (approximately 65%) were found on regions of the hosts outside of the gills (behind the pectoral fins and pelvic spines); in some cases, the copepods had inflicted significant damage to the skin of their hosts. Among host fish with evidence of an additional infection, such as microsporidian tumors (xenomas) or hemorrhagic-like symptoms (dark red abdomens and bloody mucus), the prevalence of E. labracis was significantly higher (43.4%) than among healthy fish (28.9%) despite there being no significant difference in size between the two fish health groups. In contrast, intensity (mean number of individual parasites per host) was significantly higher among healthy hosts (23.6) than among unhealthy ones (7.63). Although this parasite has been listed as present in Newfoundland previously, it has a broad host range and has been reported to be pathogenic to farmed salmonids. Therefore, its potential impact on wild and farmed fish populations around Newfoundland should not be underestimated.

A multi-proxy reconstruction of oceanographic conditions around the Younger Dryas–Holocene transition in Placentia Bay, Newfoundland

Abstract A marine sediment core from Placentia Bay off the south coast of Newfoundland was studied to reconstruct past oceanographic conditions based on a multiproxy approach, including diatoms, benthic foraminifera, grain size analysis, IP25, X-Ray fluorescence, calcium carbonate and total organic carbon content. Based on 6 radiocarbon dates, the 513.5 cm long core spans the age interval from ca. 13 to 10 cal kyrs BP and thus captures the transition from the Younger Dryas stadial into the Holocene at sub-decadal resolution. The Younger Dryas was characterized by cold Arctic water taxa of diatoms and benthic foraminifera and a stratified water column with high sea ice cover and low productivity due to strong influence of the Labrador Current. During the second half of the Younger Dryas, after ca. 12.2 cal kyrs BP, the influence of the Labrador Current gradually decreased and sea ice conditions became more variable. The transition towards the Holocene is characterized by a sequence of events starting with turnovers in the biogenic proxies followed by an abrupt retreat of sea ice and a rise in productivity. These events are believed to be related to a northward migration of the Gulf Stream–Labrador Current oceanic front. The Younger Dryas termination is directly followed by a detrital carbonate layer associated with the final phase of the Heinrich 0 event, linked to Laurentide Ice Sheet dynamics. During the early Holocene productivity remained high, with minimal sea ice cover, reduced stratification and stronger influence of warmer, Gulf Stream-derived waters.

First records of the blue runner Caranx crysos (Perciformes: Carangidae) in Newfoundland waters.

From August to September 2013, c. 21 specimens of the blue runner Caranx crysos were caught by commercial fishermen in two locations off the south coast of Newfoundland, Canada. These samples represent the first records of C. crysos in Newfoundland waters, and a potential northward range expansion of this species in the north-western Atlantic Ocean. They also illustrate the importance of fisher-derived sampling that spans times and locations outside of the limited range targeted by scientific surveys in this region.

Wind Conditions in a Fjordlike Bay and Predictions of Wind Speed Using Neighboring Stations Employing Neural Network Models

AbstractThis paper evaluates the applicability of neural networks for estimating wind speeds at various target locations using neighboring reference locations along the south coast of Newfoundland, Canada. The stations were chosen to cover a variety of topographic features and span distances in excess of 100 km. The goal of the study is to provide a general description of the summer wind conditions along the south coast of Newfoundland and to assess the potential application of neural networks for wind speed predictions. Analysis of wind data from July to October showed the wind going dominantly toward the northeast with speeds ranging from 0 to 45 m s−1. The efficacy of neural networks to predict wind speeds varied among stations and was largely influenced by the presence/absence of wind barriers. Sensitivity analysis on neural network performance concluded that an absolute minimum of 3000 h of continuous monitoring is needed to effectively train neural networks to predict wind speeds. The conclusions of this study have implications for future work utilizing wind speed data where a generalization of uniform wind speeds is assumed.

Oceanographic response to the passage of hurricanes in Belle Bay, Newfoundland

This study describes the changes in the sea surface elevation, temperature, and current pattern in Belle Bay, a side basin in a broad fjord on the south coast of Newfoundland, as a response to the passage of atmospheric instabilities. Between 11 July and 15 October 2011, Belle Bay experienced the passage of an oceanic storm (July), the hurricanes Katia and Maria (September), and hurricane Ophelia (October). In spite of the large atmospheric pressure variations, wind seems to be the main mechanism driving the sharp fluctuations in temperature and bottom currents. The response of Belle Bay to wind forcing resulted in a combination of barotropic and baroclinic processes. The barotropic response was modulated by a topographic effect, where the sea level elevation was higher near bathymetric constriction zones. The baroclinic response consisted in a deepening of the thermocline in a range of 30–40 m, evidenced by a significant increase in the temperature.

Sea cage aquaculture affects distribution of wild fish at large spatial scales

Aquaculture sea cages are fixed in space and inadvertently provide food to wild animals that is stable through time. We measured the effect of these novel and highly predictable resource patches on the distribution of wild fish across large spatial scales along the south coast of Newfoundland, Canada. Randomized stratified hydroacoustic surveys were used to compare the distribution and abundance of wild fish in bays that contained Atlantic salmon (Salmo salar) farms with control bays. Control bays were areas with no history of salmon farming but have been selected for future use by the industry. We found that measures of total area backscatter (nautical area scattering coefficient, NASC) were significantly greater in bays that contain salmon farming compared with control locations. The mean NASC in farmed bays was not significantly different from mean NASC measurements taken directly adjacent to sea cages. Variability around mean NASC estimates could not be explained by the quantity of feed available to consumers, when the number of sea cages in a farm site was used as a proxy for feed availability. Our results suggest that individual-level consumer responses at sea cages can be transmitted across larger spatial scales.

Megaflutes in a continental shelf setting, Placentia Bay, Newfoundland

Megaflutes – erosional scours normally found in deep water on continental slopes – were identified in 1978 on sidescan sonograms and seismic reflection profiles from Placentia Bay on the south coast of Newfoundland, Canada. Data from recent extensive multibeam sonar surveys provide an opportunity to describe the morphology and distribution of the megaflutes in detail, and to consider the formative processes. They occur on the east side of the outer bay, at a depth of ~200m, in a 2–3km-wide swath that continues to the south into Halibut Channel, over a total distance of ~100km. The megaflutes have been formed by removal of a layer of postglacial mud, exposing underlying glaciomarine sediments and releasing a volume of 4.5km3. They occur in a range of forms, including single, multiple, and coalescent types, and in some areas at least their inception was related to pre-existing pockmarks. Radiocarbon dates from piston cores are used to demonstrate that megaflute formation post-dated ca. 9ka. Megaflute formation in Placentia Bay has been attributed to a ‘reverse flow’ from the tsunami generated by the 1929 Grand Banks earthquake, and this is still the accepted hypothesis. We argue that the return flow from a tsunami did not generate the megaflutes, and suggest instead that they could be formed during south-flowing density currents generated when volumes of cold saline water stored in the deep (>250m) basins at the head of Placentia Bay are intermittently displaced and spilled south in a shallow channel at the east side of the bay after intense coastal surface dense water formation events, perhaps during very cold winters.

Discriminating Rainbow Trout Sources Using Freshwater and Marine Otolith Growth Chemistry

AbstractRainbow Trout Oncorhynchus mykiss are nonindigenous to Newfoundland. Subsequent to the development of marine cage rearing of Rainbow Trout in the Atlantic provinces in the early 1970s, Rainbow Trout have been captured in 33 rivers on the west and south coast of Newfoundland. These escapees may have negative impacts on wild populations, particularly Atlantic Salmon Salmo salar and Brook Trout Salvelinus fontinalis. In this study, the chemical fingerprints in the freshwater and marine growth sections of otoliths were used to distinguish three groups of Rainbow Trout of known origins: two hatcheries and one wild population. The results were then used to assign fish of unknown origin to the three known‐origin groups and thus estimate the proportion of escapees. The three known sources produced distinct chemical fingerprints in the freshwater growth of the otoliths (cross validation test, average accuracy of over 93%); whereas, the marine growth in the otoliths produced a single chemical fingerprint for the two hatchery‐origin groups distinct from the wild population. Results indicated that at least 60% of the unknown‐origin fish were aquaculture escapees. Vaterite was encountered in 70–80% of the known hatchery‐origin fish, 0% in the wild population, and 50% in the escapees. It appears that escapees with vaterite had a lower survival rate. The presence–absence of vaterite did not appear to be useful in distinguishing escapees from a wild population.