This unit, one of a series designed to develop and foster an understanding of the marine environment, presents marine science activities for fourth grade students. The unit, focusing on the various types of careers and occupations connected directly and indirectly with marine science, is divided into sections dealing with: commerce and intertidal beaches; commercial crabbing; harvesting clams; harvesting oysters; commercial shrimping; commerical fishing; and aquaculture and mariculture. Each section has a student text with related activities. Each student text is preceded by a teacher section containing information on how to use the section, additional information, and items requiring advance planning. Each activity is also preceded by a teacher background section providing additional information about the activity, including teaching hints and answer key for activities. Important vocabulary words/terms are listed in the teacher background sections; they are also underlined in the student text. Activities are designed to enhance reading as well as investigative skills; several activities provide practice in mathematics skills. Although all activities can be modified to suit individual needs or can be used "as is," it is strongly recommended that they be performed along with the readings/discussions found in student text material. (JN)