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

Lazure

Ratsimandresy

2020

Earth Syst. Sci. Data

Abstract. While the dynamics of narrow fjords, i.e. narrow with respect to their internal Rossby radius, have been widely studied, it is only recently that interest in studying the physics of broad fjords was sparked due to their importance in glacial ice melting (in Greenland, especially). Here, we present a comprehensive set of data collected in Fortune Bay, a broad, mid-latitude fjord located on the northwest Atlantic shores. Aside from being wide (15–25 km width) and deep (600 m at its deepest), Fortune Bay also has the characteristics of having steep slopes, having weak tides and being strongly stratified from spring to fall. Thus, and since strong along-shore winds also characterize the region, this system is prone to interesting dynamics, generally taking the form of transient upwelling and downwelling travelling along its shores, similar to processes encountered in broad fjords of higher latitudes. The dataset collected to study those dynamics consists of water column physical parameters (temperature, salinity, currents and water level) and atmospheric forcing (wind speed and direction, atmospheric pressure, air temperature, and solar radiation) taken at several points around the fjord using oceanographic moorings and land-based stations. The program lasted 2 full years and achieved a good data return of 90 %, providing a comprehensive dataset not only for Fortune Bay studies but also for the field of broad fjord studies. The data are available publically from the SEANOE repository (https://doi.org/10.17882/62314; Donnet and Lazure, 2020).

Section: Discussionmentioning

confidence: 91%

mentioning

confidence: 99%

A comprehensive oceanographic dataset of a subpolar, mid-latitude broad fjord: Fortune Bay, Newfoundland, Canada

Lazure

Ratsimandresy

2020

Earth Syst. Sci. Data

“…A modelling study 59 integrating the findings of Crosbie et al 58 show that avoidance of water with low salinity need to be parameterized using probability functions while ensuring not to use too strict salinity avoidance scenarios for the nauplii stages. In term of winds, given the main orientation of the bays within a SW-NE axis, a stronger effect of the wind can be expected on the circulation when winds are blowing from those directions 22 , 60 . Hence, stronger winds from the NE could have resulted in larger water movement contributing to more sea lice transmission amongst sites in 2017 and 2018.…”

Section: Discussionmentioning

confidence: 99%

Drug and pesticide usage for sea lice treatment in salmon aquaculture sites in a Canadian province from 2016 to 2019

Hamoutene

Oldford

2022

Sci Rep

We used 4 years of publicly available data (2016–2019) on chemical usage at salmon sites with information on production, stocking, locations and environmental conditions to explore patterns of anti-sea lice treatments in a Canadian province. Results show that sequential chemical treatments are prevalent, emamectin benzoate (EMB) with azamethiphos being the most used combination with a decrease in ivermectin usage. Relatively high rates of usage of EMB per fish biomass may point to potential lice resistance patterns with information needed on mechanisms and local populations. Lower or no chemical usage at some sites indicate less sea lice infestations likely influenced by localized site conditions (coves), and a lessened need for medication due to the usage of cleaner fish and possibly other non-chemical methods (not documented in this report). The year/climate influenced chemical input only in sites with higher treatment levels likely due to effects on sea lice growth and reproduction. Observed differences between years are warmer surface temperature in the fall, a higher freshwater input in spring, and stronger wind conditions for 2017 and 2018 with more medication usage for these two years. The lack of significant effect of site distances calculated in zones of influence based on 24 h potential connectivity patterns highlight the need to refine the resolution of hydrodynamic processes.

“…These studies in Bay d'Espoir were in general located close to aquaculture cages and their application to provide a general view of the oceanography of the area are therefore very limited. Due to the necessity of developing proper management planning for aquaculture activities, it is only recently that more effort has been made in further understanding the overall oceanographic conditions and water circulation in the area [7] [33]. The present work adds into this understanding by presenting analysis from more data.…”

Section: Introductionmentioning

confidence: 96%

Variation in the structure of the water column as captured by Slocum glider CTD and by CTD from a research vessel and assessment of internal waves

Ratsimandresy

2014 Oceans - St. John's

Goulet

et al. 2014

An autonomous underwater vehicle (AUV) "Slocum Glider" was deployed on the South coast of Newfoundland to collect oceanographic data from surface to 200 m depth. Between 7 March and 21 March 2012, the CTD mounted on the glider measured temperature, salinity, and dissolved oxygen at different depths along transects crossing Hermitage Bay, the area south of Connaigre Bay, Fortune Bay, and Belle Bay. Possible upwelling events were observed during the glider's survey suggesting a transport of water in and out of the area and deep water exchanges between basins.Two months later, on 5-7 May 2012, the area was revisited and the same physical parameters were measured on a lesser spatial resolution using a CTD on board of the R.V. CCGS Shamook. Variation in the physical parameters was observed with warming and freshening of the near-surface water. A subsurface layer with higher concentration of dissolved oxygen was also noted at around 50 m depth, suggesting enhanced local primary production due to internal mixing bringing nutrients towards the surface layer. The processes of heating of the surface layer and the appearance of relatively oxygen-rich water at middepth are especially of importance for the aquaculture activities occurring in the area.978-1-4799-4918-2/14/$31.00 ©2014 Crown Figure 1: Domain of interest on the South coast of Newfoundland. Only 50, 100, and 200 m isobaths are shown although the bottom can go up to 750 m in Hermitage Bay and up to 450 m in Belle Bay.