This is a new blog series using recent conditions to provide examples of using Fishing Maps. If you want the latest conditions, sign up for a subscription at the Fishing Maps store on our website.
Over the last 4 days SST has become increasingly complex, developing fronts along the coast between warm and cool water, shown by the blue circles and arrows.
The fronts can be clearly seen as the yellow coloured temperature gradients, or temperature breaks, shown by the red arrows and box on the fronts map.
Over the same period, the strong northward coastal current has weakend. This is shown by the shorter current arrows in most recent days (compare the arrow lengths in the white boxes). It is also shown by the weakening of the sea surface height (or altimetry) gradient. In recent days there is less contrast between the dark coloured green and light green. Dark green indicates lower sea surface height, or SSH, and light green marks areas with higher SSH. Reduced contrast in colour shows that the gradient is less, which produces weaker currents.
The latest chlorophyll image shows an interesting pattern of diffuse offshore streamers carrying the chlorophyll offshore. I’ve marked these streamers by the letters A, B, C, D, and E. These “streamers” resemble temporary rivers that carry coastal water with it’s associated properties, like chlorophyll and nutrients, offshore. The streamers form fronts along their edges, which you can see by matching up the labelled white lines that I have marked on the chlorophyll and the fronts map.
In conclusion:
- There are a series of fronts that have formed along the coast off the Manukau-Kaipara in the last few days.
- The temperature fronts aligned along the coast are formed at the boundary of cooler coastal water.
- The temperature and chlorophyll fronts are aligned along the edges of offshore flowing streamers carrying higher chlorophyll offshore.
- If they persist over several days, both of these types of fronts are likely to accumulate plankton and bait that will attract feeding fish.