A Little Bit More
Continuous growth in fish is not quite as simple as the poster may make it seem. Adequate food, although possibly the most important element for growth, is not the only limiting factor. In an overcrowded situation – a small pond, for example – overcrowding often causes fish to produce a chemical that inhibits or dramatically slows the growth of all those present. Farm ponds are well known for producing good fishing when first created but after a few years only stunted fish can be caught. Removal of most of the stunted fish may permit those left behind to begin normal growth again. Just how much is caused by limited space or limited food is hard to say, but under optimum conditions, fish do not stop growing throughout their lives.
Biologists have long known how to age fish by looking for the “annual rings” on their scales and bones in much the same way foresters read tree rings. Fluctuations in water temperature and increased or decreased feeding activity, especially in areas where there are seasons, is evident in the increase and decrease of a fish’s growth
Activities
It Was This Big
Objectives: Convert English measurements to metric
Materials: Calculator (optional), pencil and paper
Although almost the entire world has gone metric, the United States seems reluctant to accept the inevitable. Converting from English to metric is a good math exercise for your students and maybe soon, even U.S. citizens will be using the metric system exclusively. In the activity with the Skinny Minnie unit, students were asked to work with distances in the metric system. Now, let’s work with metric weights.
1. Have your students look up your state’s fishing records (all the states are listed at www.statefishingrecords.com/) and select 5 fish (maybe ones they’ve caught or would like to catch).
2. Have them take these record English weights and convert them into the metric system. You’ll find the weights in pounds and ounces (eg. New York State Cisco record is 5lbs7oz) so students will have to do some computation to make an accurate conversion. Have your students show their work so you’re sure they understand the procedure.
1 pound = .45 kilograms
Key Concepts
Growth and Development, Structures and Functions
Questions
Do you have a question for a naturalist? Go ahead and ask!
It's easy -- just fill out this form, submit your question and you'll receive an answer shortly.