The right time to eat

Phytoplankton bloom off western Iceland. Taken by NASA's Aqua satellite. Adapted from NASA/Goddard Space Flight Center/Jeff Schmaltz/the MODIS Land Rapid Response Team (http://climate.nasa.gov).

Fish struggle to survive from their first glimpses of life. These are days of extreme caution for a fish, for they rely on their surroundings to grow and face predators. The number of fish that will be available for us (consumers) will greatly depend on the ability of a fish to surpass these stages. This critical period is commonly linked to the "match-mismatch hypothesis", which states that survival of fish larvae depends on whether the peaks of both hatching of the larvae and phytoplankton production match in space and time.

In order to understand how fish can survive during its early life-stages, one may have to focus on a bottom-up approach. In common terms, this means to be looking for what is below in the trophic web - food concentration, or prey availability. However, the amount of food is not the only factor to consider. It is important to know when and where the food is. Since timing of primary productivity affect larval fish growth and survival, assessing phytoplankton bloom dynamics is a indispensable step to study fish larvae in the northeast Atlantic (Fig 1).

Phytoplankton are drifting organisms that require light and nutrients to either photosynthesis (light energy) or chemosynthesis (chemical energy). Chlorophyll is one of their pigments, which can be detected from space, through satellites' products (ocean colour). Therefore, the ocean colour may be used as an index of phytoplankton, the basis of life. When phytoplankton blooms form, they attract zooplankton communities. These, in turn, serve as food for larval fish. Once this links are made and a match exists in time and space, there are higher chances of us (scientists) to be able to improve predictions of the distribution of North Atlantic fish. Et voilá!

By Sofia Ferreira, NorMER PhD student
Published Feb. 25, 2013 11:34 AM - Last modified Apr. 25, 2013 9:24 AM