Thursday, March 3, 2011

Nurseries and Schools

Nothing groundbreaking about otoliths in this post but it will be about fish...and schools...and nurseries (and it might be a little political).

My primary interests in terms of fisheries science is probably identifying nursery areas used by fish, and in fact this topic has become the primary focus of my research.  

What is a nursery area you may ask?  The traditional definition is something along the lines of an area where juvenile fish are found at high densities, more successfully avoid predation, or have faster growth rates.  This definition is simple and fits rather well.  Nursery areas can be identified by the presence of high densities of individuals, that are better able to survive and grow because of some component of the habitat.  Submerged aquatic vegetation, coral reefs, rocky structures, and wetlands are all examples of habitats that serve as nursery areas for.  These habitats provide shelter from predators and adequate food that allows juvenile fish to survive and grow.

When identifying the most important nursery habitats a better definition may be the one proposed by Beck et al. (2001) which states; important nursery areas are those where production of individuals that recruit to the adult population is greater than production from other habitats in which juveniles occur.  Let me explain further using an example (this is a hypothetical example don't read to deeply into the biology).  We observe two similarly sized seagrass beds, we'll call them north and south, both provide nursery habitat for juvenile spot.  The north and south seagrass beds have similar densities of juvenile spot, but more juveniles from the south seagrass bed survive to become mature adults than from the north.  Despite similarities in juvenile densities we would say that the south seagrass bed is a more important nursery habitat because more spot survive to adulthood and are able to spawn themselves.  It is generally accepted that an animal is successful if it is able to reproduce, therefore when judging the success of fish the individuals that reproduce are considered successful.

This definition is though provoking and interesting (I'll admit I was a little giddy when I first read the paper) but it is difficult to apply because of the difficulty in tracking fish throughout their lives from the juvenile to adult stage.  However, two methods; otolith microchemistry (which I am attempting to use) and genetic analysis have shown promise in matching adult fish to nursery areas.

But why go through all that trouble?  Why do we even care about nursery areas?  We care about nursery areas because it is the habitat used by fish during a life stage when they are particularly vulnerable.  In addition, nursery areas like seagrass beds, coral reefs and wetlands are often habitats that are threatened by the human activities.  So much research has been focused on identifying and protecting nursery areas because they are essential for maintaining healthy fish populations.  Basically, by investing in the protection of juvenile habitat we're hoping more adults will be produced.

Now, I am going to completely switch gears and talk about humans and more importantly human nursery areas.

Comparing fish and humans is a bit of a stretch because survival of fish and survival of humans are based on very different factors, but similarities can be drawn between the two.  When thinking of human nursery areas two places come to mind, a child's (juveniles) home or school.  At home a child presumably receives some form of parental care and is fed and sheltered.  In school children learn both academic and social skills and what they learn/do in school largely shapes the type of adult they become.

Looking back to the original definition of nursery habitat we can attempt to apply it to schools.  Nursery areas are identified by high densities of individuals, that are better able to survive and grow.  Schools generally have high densities of individuals, they provide some type of shelter (both literally, and figuratively), and students grow mentally, socially and physically while in school.

But can we apply the definition suggested by Beck et al. (2001) to schools?  The measure of success of a human is harder to define than for a fish.  If a fish survives to reproduce it is considered a success, but does the same hold true for humans?  Some people would say yes, but measures of success are relative and based on opinion.  Because I am writing about schools and often times it seems as though success is based on dollars and cents, I am going to consider a successful human to be one who joins the workforce (doesn't matter how much money and individual makes).  Using these criteria we would consider the most important human nursery areas (schools) to be the ones that produce the most adult humans that join the workforce.   

Based on these comparisons it seems that schools provide essential nursery habitat for humans and are an important part of our life cycle.  So why should we care?  In order to maintain healthy populations we have to protect these nursery habitats, similar to fish we invest in juvenile habitats to protect the future.  The similarities don't end there, just like nursery habitat used by fish schools are becoming more and more threatened.  Budget cuts have been a prominent feature in the news recently and apparently the primary target seems to be schools.  Because I am most familiar with Wisconsin (having lived there) I have been closely following the financial situation.  Wisconsin gov. Scott Walker has proposed $800 million in cuts to schools as a way to eliminate the deficit.  Investing in schools seems essential in order to ensure the success of future generations, and allowing schools to slip away seems similar to destroying essential nursery habitat.


Beck, M.W., K.L. Heck Jr., K.W. Able, D.L. Childers, D.B. Eggleston, B.M. Gillanders, B. Halpern, C.G. Hays, K. Hoshino, T.J. Minello, R.J. Orth, P.F. Sheridan, and M.P. Weinstein.  2001.  The identification, conservation, and management of estuarine and marine nurseries for fish and invertebrates.  Bioscience 51(8):633-641.


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