Biology of Fish Age and Growth Assignment

Relationship between age, growth, and length in White Grunts from the Gulf of Mexico

Kimberly A. Heater

Abstract

Haemulon plumieri is a tropical/warm-temperate fish with a wide range and commercial/recreational importance. Despite its economic importance, the species is left largely unregulated. Recent studies have sought to fill in the data gap on these species to understand the effect fishing is having on the population. This study looked at this species and compiled data on its age, length, and weight. The age was calculated using three different otolith methods: whole, sectioned, and break and burn. This allowed for a comparison of the methods along with multiple ages for each fish. The data collected in this report was then compared to the von Bertalanffy growth curve calculated in Murie and Parkyn 2005, to see if the data fit that curve. It was found that the Gulf of Mexico white grunts fit the curve, but also fit many standard growth and age relationships seen across many fish species.

Introduction

The relationship between age and growth has been analyzed for many fish. Age can be calculated in many ways, but for fish is usually calculated by the otolith’s in the ear. There are three main ways to age an otolith; first the rings can be counted on the whole otolith, second the otolith can be sectioned and the rings can be counted, and finally the otolith can be broken and burned. Each methods has it’s advantages and disadvantages, along with an accuracy. Growth in fish is measured in two main ways; either by weighing the fish or getting some measure of its length. The white grunt is a tropical/warm-temperate water species that ranges from the coast of Virginia to Florida, into the Gulf of Mexico, throughout the Caribbean, and all the way south to Brazil (Hoese and Moore 1998). All of this data has been calculated for the Haemulon plumieri which is more commonly known as the white grunt. This is due to the white grunts importance as a commercial and...