ROUNDTABLE SESSION 3 REINTRODUCTION OF NATIVE CRAYFISH AND HABITAT RESTORATION

Abstract

The aim of this roundtable session was to discuss reintroduction of native crayfish and habitat restoration providing practical recommendations of value to environmental authorities, decision makers and local managers. A (re)introduction may be appropriate: a) to reintroduce a population recently lost, b) to extend the distribution of an ICS into historic range and c) to create new or isolated populations to conserve genetic diversity or the species. Before (re)introduction it is imperative to demonstrate the probability that the receptor locality is empty of crayfish, to know the reason for crayfish extinction, and that the reason is removed before restocking. Before restocking, the receptor locality should also be assessed for crayfish suitability, including: water type and chemistry, physical conditions (shelter), presence of crayfish plague, risk of NICS, predatory fish. In general, major constraints in a restocking project is money and availability of stocking material. General recommendations: a) if have abundant/readily available and acceptable donor population use adults and young/juveniles as available, b) if short of stock boost with hatchery rearing, and c) if want population quickly, stock as many as can afford and several times. Trade offs: time vs. cost. Genetic distinctiveness/possible spread of diseases must be considered. In general, the preferential ranking is donor from: 1) same watercourse, 2) same catchment, 3) adjacent catchment or one nearby in the same biogeographic region for crayfish, and 4) any other catchment. Habitat restoration can be a valuable action, and should be prioritised to: 1) give greatest overall benefit to the ecosystem, 2) benefit ICS and 3) be achievable and cost effective. Natural characteristics of waterbodies in local area should be considered. A key factor in the protection of ICS populations is the knowledge and attitude of local people. Objectives and actions should be agreed with local stakeholders to improve chances of success.