Critique of:

Belk, M.C. 1995. Variation in growth and age at maturity in bluegill sunfish: genetic or environmental effects? J. Fish Biol. 47:237-247.

The purpose of this research article is to determine if the cause of the variations in growth and age at maturity in bluegill sunfish is genetic or environmental in nature. After monitoring bluegill growth and development in a controlled environment, Belk came to the conclusion that the basis for variation is environmental. Overall, this research article is well written. However, there are some necessary modifications that would greatly improve the paper.

The title and abstract are very effective. The title clearly states the objective of the experiment, and the abstract gives an accurate overview of the research. The introduction is also well written, stating the goals of the experiment and its relevance to evolutionary biology. The materials and methods section, however, is in need of some improvements.

Most importantly, Belk rules out the genetic effect on variation without conducting any type of genetic screening on the samples. He mentions only protein electrophoresis conducted twenty years ago. An analysis of allozymes or mitochondrial DNA in the samples being tested would greatly enhance the conclusion and its relevance to evolutionary biology. Also, the sample used could be improved. The sample size is small, and the fact that neither the hatchery fish nor the reservoir fish are subject to natural predation, such as human predation, may affect the data. A large sample size collected from a more representative setting would improve the accuracy of the data.

The results of the experiment are well stated, but the discussion of these results could be improved. Belk relies on previous research (most of which occurred over ten years ago) without clearly explaining the relevance of these studies to his own study. It is necessary to address the issue of genetic studies in this area in order to fully dispel this theory.

As a research paper, this article is well written. The experiments conducted, however, must be improved in order to most accurately support the conclusion.