Sauwai Hung

Date

4-2009

Project Type

URC Presentation

College or School

COLSA

Class Year

Senior

Department

Biological Sciences

Major

Zoology

Faculty Research Advisor

Larry Harris

Abstract

Background

Three decades ago, the increased demand for sea urchin roe stimulated large scale harvesting of the green sea urchin Strongylocentrotus droebachiensis from the Gulf of Maine. Beginning in 1987, the rapid rise in harvests off the coasts of Maine and New Hampshire made urchin recruitment the second largest wild fishery operation behind lobsters with a peak of 39 million pounds in 1993 (1). Since then, the subsequent decline in harvests paralleled the reduction in urchin populations especially in locations where natural recruitment occurred at high densities. This drastic shift in ecology can be observed in the southwestern portion of Maine, where extensive areas of urchin-dominated communities have become algae-dominated and completely devoid of urchins (1, 2). The overfishing of sea urchins led to increased interest in a hatchery system for stock enhancement and replenishment of natural populations.

The goal of the hatchery system is to produce commercial quantities of sea urchins for out planting into the wild as quickly and economically as possible. Currently, it appears out planting is most successful in the winter. Since spawning begins by January or February, this design allows the urchins one year from spawning to out planting at the preferred test diameter of 15 mm (1). From newly settled (0.5 mm) to out planting (15 mm), the goal of the hatchery system is to rapidly while efficiently increase the somatic growth rate of the animals.

Problem

The goal of the hatchery is to produce commercial quantities of the animals in the least amount of time and with the most economical method. However, urchin feed is not well studied for its nutrient composition in relationship with somatic growth especially during the juvenile stage of the animal as it reaches the out planting test diameter of 15 mm. Therefore, current feed could be inept in providing the greatest rate of growth possible for the urchin hatchery. The nutrient composition of urchin feed is a key factor in the efficiency of the hatchery process.

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