Fish or human pee. Whose is better?


Jake in seagrass2


Nutrients in the form of fish pee have been shown to be beneficial for seagrasses, mangroves and coral reefs and our previous research suggests that overfishing is reducing the amount of fish pee in the coastal oceans.  But a question that arises time and again when people hear this finding is: “if overfishing is bad because it reduces nutrients, why can’t the nutrients that humans are adding to the ocean supplant those lost by overfishing?”.  This question is a very good one, and it is notable the frequency at which Bahamians, and specifically fishermen, asked it.  Truth be told, we simply don’t know the answer.  Our hypothesis is that there are subtle differences in the amount of phosphorus (P) relative to nitrogen (N) supplied by fish pee and human nutrients, human nutrients having more P.  This difference, even though likely small, might fundamentally affect the growth of seagrasses and algae and the relative dominance of these species, aspects that can have important ecological implications.

With the help of a savy Frenchman in Little Harbour, we have been maintaining a constant (albeit small) amount of fertilizer input to 8 of 16 reefs (the other 8 have various levels of fish around them) in the Bight of Old Robinson here on Abaco over the past 2.5 years.  The first full-fledge sampling of these reefs was just completed and in the past weeks we have conducted nearly 8,000 measurements of seagrass growth rates and collected loads of data on other key factors that will ultimately help us tease apart differences between fish pee and human nutrients.  If our hypothesis is correct, then this research will be important for helping direct conservation measures to mitigate human nutrients.  If it is not correct, it would be great because it will suggest human nutrients may not be as bad as we think, though it will also require much more research to understand why.  My guess is that our findings will lie somewhere in between, providing a few key bits of useful information that may benefit conservation, but also creating a mess of new (but exciting) questions.  So goes field research.  Updates to come……

By | 2017-12-01T14:03:47-05:00 June 6th, 2013|Categories: Artificial Reefs, Current Events, Nutrients, Overfishing, Uncategorized|Comments Off on Fish or human pee. Whose is better?

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