Additional Bottom-up Projects

In addition to the above projects, two additional projects were developed in 2015-2016.  One is related to monitoring of ocean acidification of the Salish Sea (including evaluation using the Citizen Science vessels) and the effect of acidification on the marine ecosystem within the Strait of Georgia; and a second project is related to the incidence and impact of Harmful Algae Blooms on juvenile Pacific salmon.  The incidence of these blooms appears to be increasing and may contribute to reduced survival of salmon.

Harmful Algal Program – Canada

Team: Svetlana Esenkulova (PSF), Nicky Haigh (HAMP)

Objectives: To determine the prevalence of harmful algal blooms in the Strait of Georgia and their impact on juvenile salmon.

Background: The harmful algae program was developed during 2014 with a pilot study in Cowichan Bay. This program is now fully implemented with collections of phytoplankton taking place throughout the Strait of Georgia in the citizen science program. Samples are being collected from stations from February to November, primarily from surface waters, but at a number of depths (surface, 5, 10, 20m) from 3-4 priority stations. Phytoplankton data collected are biomass estimation, identification and enumeration of dominant species, % of constituent groups (diatoms, dinoflagellates, silicoflagellates, raphydophites, nanoplankton, zooplankton), and identification and enumeration of all harmful algae. The water quality data collected concurrently with the phytoplankton samples will be used to determine the conditions that appear to promote the development of harmful algal blooms.

Lab studies to assess the conditions that promote development of harmful toxins are currently under development. The field project may be augmented in 2017 with studies to assess whether juvenile fish are able to actively avoid blooms in marine waters.

Status: Based on thousands of samples (collected bi-monthly from February to October at ~80 sites) in 2015 and 2016, they have unprecedented, high-resolution data on phytoplankton dynamics in the Strait of Georgia. Phytoplankton biomass and composition were strikingly different in 2015 and 2016, and appear to be closely associated with nutrients and environmental parameters. There is a clear synchrony in phytoplankton dynamics across the Strait, however it differs significantly on location-scale. They observed effects of harmful algae on juvenile salmon in Cowichan Bay in 2014, 2015, 2016 and the effects were consistent with these confirmed on salmon farms in BC and papers worldwide.

2015

An unusually early spring phytoplankton bloom in 2015 was associated with higher than normal water temperatures in the Strait of Georgia and early snowmelt. Lower summer biomass and dominance of diatoms (low dinoflagellates contribution, silicoflagellates, and raphidophytes) were associated with lower than usual river discharges and rainfall in summer. The year of 2015 was unusually quiet in terms of harmful algal blooms: there were no toxic blooms to salmon throughout the sampling period; moderate and high levels of Chaetoceros convolutus/concavicorne (mechanically harmful to salmon) were observed in Cowichan Bay, Baynes Sound, Campbell River, Lund, Powell River, and Irvines Sechelt at the end of May and beginning of June.

2016 

In 2016, the spring bloom was recorded several weeks later than in 2015; it was comprised by a mixture of species (Thalassiosira spp., Skeletonema costatum, Chaetoceros spp.), whereas the spring bloom of 2015 was comprised mostly by one species (Skeletonema costatum). The phytoplankton composition (in terms of groups: diatoms, dinoflagellates, etc.) in 2016 was more normal then in 2015. The year of 2016 was somewhat unfavorable in terms of harmful algal blooms: there were elevated levels of non-skeletal Dictyocha (toxic to salmon) observed after periods of heavy rains in some areas, moderate blooms of Rhizosolenia setigera (mechanically harmful), low-moderate levels of Heterosigma akashiwo (toxic) in few areas in late August/early September samples. There were several non-harmful blooms (Ditylum brightwellii, coccolithophores) observed in summer.

Observing non skeletal Dictyocha in the field Cowichan Bay, summer 2016

Outcomes:

  • High-resolution, in situ data on phytoplankton dynamics in the Strait of Georgia, 2015 and 2016, provided a solid foundation for understanding bottom-up control of zooplankton and herbivories fish dynamics (bottom-up control for salmonids). With an additional data from 2017 (a year not affected by El Nino), it will be possible to establish a statistically significant links between phytoplankton and environmental characteristics in the SoG. Having enough zooplankton data, will enable to investigate environment-phytoplankton-zooplankton relationship and (in cases when zooplankton sampling is limited) to anticipate/forecast trends of juvenile fish food abundance based on environmental/phytoplankton data.
  • Studying effects of harmful algae on wild juvenile salmon in the Cowichan Bay 2014-2016 (top-down study) provided a body of evidence that wild salmon is negatively affected by harmful algae in the same way as the aquaculture salmon in BC (harmful algae directly affect salmon survival: toxic algae through acute or chronic toxicity and mechanically harmful algae through gill damage).
  • Unexpected outcomes: juvenile salmonids significantly reduced feeding and their diets were somewhat unusual during high biomass (very thick) non-harmful blooms.
  • Collected data, observations, and analysis of phytoplankton dynamics (including harmful algal blooms) could potentially increase hatchery salmon survival through timing of the hatchery releases with favorable phytoplankton conditions. Continuing phytoplankton monitoring program (e.g. Citizen Science Program or smaller scale program in important to juvenile salmon areas) provides information (both bottom-up and top-down in terms of phytoplankton effects on juvenile salmon) that can improve the accuracy of adult returns forecasting and reducing uncertainty around the role of the marine environment in overall productivity.

A New Component of the Citizen Science Program: Ocean Acidification Monitoring

Team: Wiley Evans, Alex Hare, Eric Peterson, Hakai Institute

In the summer of 2016 the Hakai Institute began a partnership with the Pacific Salmon Foundation’s Citizen Science (PSF-CZ) program to evaluate the potential for ocean acidification in the Strait of Georgia. Ocean acidification is the process of increasing the ocean’s level of acidity, termed its “pH”, and is caused by increasing amounts of carbon dioxide from the atmosphere dissolving into the ocean.

The effect of changing ocean pH on marine life differs widely between species and currently little information is available about the long-term consequences of such change on coastal environments. The seawater chemistry in coastal settings can also vary widely between nearby areas and over short timescales, adding complexity to the situation. The Hakai Institute and PSF are addressing this shortcoming in knowledge by combining their abilities to collect water samples and make seawater carbon dioxide measurements at locations throughout the northern Strait of Georgia (Figure 1). Scientists from Hakai’s Ocean Acidification Program will then use the measurements to determine how carbon dioxide behaves in the Strait of Georgia and to investigate the potential of ocean acidification in the region.

Figure 1. Left panel: blue circles represent where water samples for ocean acidification measurements were collected in the Baynes Sound, Desolation Sound, Sentry Shoal, and west Texada Island areas by the PSF’s Citizen Science program in the summer of 2016. Right panel: PSF’s Citizen Science crew collect water samples in the Desolation Sound area.

One of the key pieces of information produced by the Hakai and PSF partnership is how suitable the seawater conditions are for growth by marine shell forming animals, and how these conditions change on daily to monthly timescales. This information comes from the measurement of a water property termed ‘aragonite saturation state’, which changes when seawater carbon dioxide concentrations and pH level change. Measurements from the summer of 2016 show that saturation state conditions differ between areas of the northern Strait of Georgia, and change from month to month (Figure 2).

Figure 2. Aragonite saturation state in surface water of the northern Strait of Georgia in 2016. Coloured circles in the images represent saturation state values at those locations according to the colour bar at the right side of the figure.

The Hakai Institute’s Ocean Acidification Program team is looking forward to continuing this work with the PSF’s citizen science program in the spring of 2017, and is interested in expanding coverage to include more southerly areas of the Strait of Georgia. By increasing the area over which measurements are taken, better information can be produced to understand the potential of ocean acidification in this region. More information on this topic is available from the Hakai Institute, and interested persons are welcomed to use the contact information below.

The Hakai Institute: www.hakai.org

Ocean Acidification Program contact: Alex Hare, alex.hare@hakai.org

Quadra Island Field Station: 250.285.3134