Water / Eau



Changements
climatiques,
courants
océaniques
et pêches

La science doit reprendre son véritable rôle et s'établir comme premier gardien des océans.

Nous devrions tous surveiller les relations entre les changements climatiques, les courants océaniques et les pêches parce que les poissons eux-mêmes pourraient bien s'avérer être l'espèce indicatrice. 

Il est plus important que jamais de tenir compte de facteurs comme les changements climatiques avant que nous soyons obligés de faire appel à une gestion de crise.

Et quand la prévention n'est plus une alternative possible, nous devons être prêts à prendre les mesures nécessaires pour préserver les espèces menacées quels qu'en soient les coûts.

 

 

Climate change, Ocean
Currents and Fisheries


Hugh Akagi
Environmentalist
April 2003

as I write this article, I see the headline for CBC News (dated Wed, 09 Apr 2003) which reads:

Super-cold water still lead suspect in cod die-off:  St. John’s - Water temperatures in the Newfoundland bay where a massive cod kill occurred are the coldest measured in decades.”

temp changes

The obvious factor brought into play by ocean currents and climate change would be temperature changes.  In any scientific research, this is a basic parameter and its impact on a species can be quite dramatic in determining size, reproduction, and survival[1]. Temperature is also a major factor in the occurrence of HABs (Harmful Algal Blooms), which heavily impact areas used by the shellfish industry. In the case of Domoic Acid in 1987, the effect on the industry was devastating, as a great deal of damage control had to be applied when the toxin caused human fatalities.

Temperature is not the only factor, as climate changes affecting ocean currents could cause upwelling and gyres, shifting salinity and phytoplankton distribution. Monitoring these and other factors will provide the knowledge necessary to determine what has happened in the past; however, to proceed to the next step requires another tool, modeling. With the power of today’s computer technology, it is possible to predict different scenarios based on these changing parameters. Though there is a degree of certainty, it is the unpredictability of each species which makes it impossible to determine what will happen. The combinations resulting from the links between the different fisheries and numerous variables begs caution as we interpret the results. As for the factors we can control, in the case of climate change, the ever obvious reduction in the use of fossil fuels, and, in the case of the fishery, safe limits with regard to catch. 

Climate changes are the target of very extensive research being carried out by various departments, including government agencies, universities, and focus groups. The cause and effect are all to be viewed under a microscope until we can determine:

1) the implications to the human species; and

2) what we can do about it.

The area with the greatest flexibility for input would be the implications to the human species. Here we would find the impact of climate change on our oceans and that resource so precious to humans, the fishery.


Warm surface water cools as it flows into the North Atlantic, releasing heat to the atmosphere and eventually sinking


(image: David Suzuki Foundation)

As many species previously ignored by industry are now being taken from the oceans, we must not only monitor the impacts of climate change on them, but the effects compounded by each new fishery. This increase in fisheries lowers the tolerance for stress due to global warming on any of these species, which now include rockweed (ascophyllum nodosum), sea cucumbers (cucumaria frondosa), and sea urchins (strongylocentrotus droebachiensis).

The reason for concern may require a short history lesson and a few equations. Both are products of some very basic principles that must be adhered to if we are to remain a successful species on this planet.

  • The equation for the survival of a fishery must
    be: Input>Output

  • For a sustainable fishery the equation might
    look like this:  Input=Output

  • For a fishery in trouble the equation became:
    Output>Input

With the realization that we are fishing at a very high capacity (efficiency, above and beyond), comes the understanding that today’s fishery (for many species) is a fragile commodity. Hence the importance of at least monitoring any activity which might have a negative impact on either the species or the industry.

(photo: NOAA site)It is possible to impact one and not the other. If the species suffers and the industry continues, it may be a few years before realization sets in that the fishery must adjust accordingly. This is a worst case scenario for the species.

An example in which the industry may be impacted but not the species would be a temperature change resulting in the species abandoning an area and moving beyond the range of the fishery. Here the changes would be to the local ecosystem,[2] and everyone knows, a missing link could have severe repercussions, perhaps starting a chain reaction.

Conceivably the price of having such a productive (demanding) fishery is “constant vigilance”. As each link in the food chain becomes a target, it becomes more vital than ever to account for other factors such as climate changes affecting our oceans before we need crisis management. Whatever leads to a shift in any fishery toward “Output>Input”, we will need to understand. If and when such a shift occurs, we will need to be ready. When prevention of a crisis is no longer an option, we must be willing to take the steps necessary to preserve the species, whatever the cost.

Science must take the leading role and establish itself as the true stewards/ caretakers of our oceans. The math is clear, if the fishery is a function of the species, then the fishery can only exist if the species exists! There can be no room for compromise knowing this equation may not be reversible!  The links between any climate change, ocean currents and the fishery will all bear watching while the indicator species may very well be the fish themselves.


(photo: NBEN/RENB)

For a more in depth look at this subject I would recommend viewing the research done by Dr. Fred Page and his scientific team at the Biological Station in St. Andrews, N.B.  Their work on ocean currents and modeling may well be a reference point for things to come. The HABs and phytoplankton monitoring/study is the long-term project of Jennifer Martin, also at the Biological Station in St. Andrews.

 

[1] Percy, J.A. Whither the Weather? Fundy Issues #18 (BoFEP), 
      Spring 2001 p5

[2] Ibid