Science of salmon stocking: report

6. Plan

In order to both reduce/eliminate negative ecological impacts and maximise the ability to meet conservation objectives, it is vital that a management plan is developed in support of each stocking proposal. This formal plan should cover the rational, objectives, operation, monitoring and cost/benefit of the intervention. Although historically there has been large resource-investment in stocking activities, weaknesses in the success of many schemes appears to be the result of indiscriminate stocking without well-defined objectives or prior appraisal of the likelihood of success (Cowx et al., 2012). Development of a detailed plan allows the various aspects of the intervention to be examined and the likelihood of achieving goals evaluated.

Management plan requirements vary depending on the regulatory requirements under which the activities are to take place. Hatchery interventions associated with US Pacific salmonids under the Endangered Species Act (ESA), for example, produce a standardised Hatchery and Genetics Management Plan (HGMP) (NOAA, 2020) which is used by the National Oceanic and Atmospheric Administration (NOAA) to evaluate impacts under the act. In contrast, in Canada, there is no federal policy that guides stocking and enhancement activities for Atlantic salmon, although some provincial governments have developed policies, and stocking activities by governmental and non-governmental organizations (NGO) are reviewed by defined oversight committees (NASCO, 2017a). In France, stocking is financed by the French government, with the support of local and regional authorities and based on a Migratory Fish Management Plan (plan de gestion des poissons migrateurs, PLAGEPOMI) for each major river basin (NASCO, 2017b). The Norwegian Environment Agency is the main regulatory authority in that country and The Norwegian Food Safety Authority and the Norwegian Water Resources and Energy Directorate also regulate hatcheries (NASCO, 2017c). There, stocking must be based on an approved plan, specific to the river concerned (Chaput et al., 2017). In England, stocking regulation comes under the auspices of the Environment Agency (EA) and all stocking is expertly assessed on a case-by-case basis to determine if it meets the various criteria set out in the EA's best practice and guidance documentation (NASCO, 2009). In Wales, stocking has been prohibited (Natural Resources Wales, 2014).

In Scotland, stocking programmes are regulated and authorised by various bodies under several legislative acts. Collection of wild broodstock in the close season is regulated by Marine Scotland acting on behalf of Scottish Ministers with hatchery operations controlled to some extent via fish health legislation. However, associated stocking of Atlantic salmon and sea trout is authorised directly by Non-Governmental bodies known as District Salmon Fishery Boards (DSFB) where these exist. In areas with no DSFB and for all other freshwater fish species, Marine Scotland regulates stocking, with detailed proposals from fishery operators being assessed on a case-by-case basis against the requirements of the Scottish Government stocking policy. DSFBs have their own individual criteria for assessment. Scottish Natural Heritage SNH (an agency of the Scottish Government) has a lead licensing responsibility for any proposed introduction of a species outside their native range, for example salmon stocking above an impassable natural barrier. Post authorisation, management and implementation of stocking is then carried out by DSFB's and/or fishery owners/operators.

Notwithstanding the variation in regulation among different countries, in many areas a general commonality in approach is the development of a science-based plan covering all the various aspects related to stocking, as outlined above, followed by expert evaluation through the lifetime of the proposed programme. In order that all aspects of the programme are covered, standardised planning documentation provides the best chance of capturing the various information required to make informed decisions. A particularly well-developed example of such an approach is the HGMP approach used in Pacific salmonid stocking. Numerous plans have been produced for individual supplementation schemes and are available to both NOAA and to the public for comment (template and guidance on NOAA, 2019).