Research Document - 2000/109

Management of the Nova Scotia Sea Urchin Fishery: a Nearly Successful Habitat Based Management Regime

By Miller, R.J., Nolan, S.C.

Abstract

In the Nova Scotia green sea urchin fishery licensees fish either competitively, usually limited to the waters adjacent to one county, or fish restricted zones with only one license per area. There are no seasons and only a small area is regulated by quota.

Restricted zones are an important part of a habitat-based management regime. In exchange for the privilege of exclusive access to fishing grounds, fishers are obligated to fully use and enhance the habitat carrying capacity. Enhancement is accomplished by manipulating the urchin stock and its food. Advantages of the restricted zones over competitive fishing are: reduced costs of enforcement and assessment, lower cost of fishing, higher value of catch, reduced barriers to sharing information, and freedom to implement a harvest plan without interference from other fishers. Disadvantages are high start-up costs, unwillingness of some fishers to release area they are not fishing, and strong opposition from outside the fishery.

Stock assessments provide the number of licenses that can be supported rather than the more usual weight that can be harvested. Surveys measure the length of urchin feeding fronts at the deep edge of algal beds. Most harvesting occurs in these fronts and each licensee is able (or willing) to harvest only a finite length of front in a season. Resource audits to determined whether fishermen were managing their zones well measured the depths of the urchin feeding fronts. There is an optimum range between deep enough to leave adequate algal production and shallow enough to be accessible to divers. Catch per unit effort was not an index of stock abundance. 

Diving is not perceived as a threat to the sustainability of the stock because urchins occur deeper than the harvest depth, sexual maturity is well below the minimum harvest size, and many legal sized urchins that spawn have mature gonads below market quality. 

Disease caused by amoeboid pathogen is the biggest threat to the stock and to the fishery. From 1995 through 2000 disease killed 10-100 times the weight of urchins taken by the fishery. We have no method of preventing the spread of disease. 

The fishery began in 1989 and has had annual landings up to 1300 t taken by as many as 36 active licenses.

Complete document (PDF, 436 KB)

Accessibility Notice

This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.