Escaped Rainbow Trout (Onchorhyncus mykiss) Management 2018 Operational Plan

Transcription

1 Escaped Rainbow Trout (Onchorhyncus mykiss) Management 2018 Operational Plan Internal Document Last updated 9 th May 2018

2 INTRODUCTION Following the escape of a significant number of rainbow trout (Onchorhyncus mykiss) from Rocks Lodge fish farm on the River Strule during the flood of August 22 nd 2017 the Loughs Agency has instigated a number of co-ordinated actions as part of the response. To date these have included: In the immediate weeks post the escape anglers were urged to report all catches of rainbow trout to the Loughs Agency, Liaison with angling representative bodies, Liaison with the fish farm operator, Liaison with the regulator, External report commissioned, Trials of boat based electrofishing as a method of recovery, Trials of fyke netting as a method of recovery, The development and implementation of a rod based survey method to monitor the distribution and abundance of rainbow trout during the annual closed season, Analysis of captured rainbow trout including size, condition and feeding behaviour. Following the initial response at the tail end of the 2017 fishing season and during the annual rod fishery close season during 2017/2018 the Loughs Agency intends to continue the delivery of response measures. An operational plan for 2018 has been developed and is outlined below. Page 2 of 9

3 2018 OPERATIONAL PLAN Based on the information collected to date the Loughs Agency will continue to develop all possible methods for recovery of rainbow trout while conserving and protecting the native fish populations of the Foyle area. April, May and June are significant periods during the lifecycle of native salmonid (Salmon and Trout) populations. Smolts descend our rivers at the start of their seaward migration. Any form of survey including rod fishing, netting and electrofishing has the potential to intercept large numbers of migrating salmonid smolts amongst other native fish species. After careful consideration it has been decided that no Loughs Agency targeted recovery effort will commence until after the smolt run has ended. Rod fishers will be urged to report all rainbow trout captured. The following methods may be utilised during 2018 to aid in the recovery of escaped rainbow trout and to monitor their distribution, abundance and condition. 1. Recreational fishery rod catch returns (in season and end of season). o Encourage anglers to report captures of rainbow trout in season. o Encourage anglers to surrender rainbow trout over 30cm for analysis. o Negotiate and organise a structured angler based fishing effort to maximise removal at suitable locations. 2. Loughs Agency rod based survey post, smolt run. o Mid-June and September surveys. o Monthly surveys in the 2018/19 closed season (Nov-Mar). 3. Targeted netting operations, directed by the results of the distribution and abundance survey and suitable habitat types. o Pending permissions, access/egress and suitable river conditions, sites such as Sion Mills lade and the Feddens will be targeted. 4. Continuation of electrofishing trials dependent upon river conditions. 5. Communication o Continue to listen to and engage with our stakeholders. o Release regular updates via on and off-line channels. Page 3 of 9

4 RESOURCES Due to the intensive nature of the recovery methods, appropriate resources will be made available including, personnel and survey equipment. It should also be noted that due to the nature of the habitats, accessibility to holding waters and the transient nature of the rainbow trout, significant recaptures may not be achieved. It is highly likely that the best method of recovery will be through the coordinated efforts of licensed recreational fishers working in co-operation with the Loughs Agency to target known hotspots. This will require co-ordination and may encounter problems including access to private fisheries and permitting. Most mortality is likely to occur from either starvation or predation. It is recommended that predator numbers are also recorded. Page 4 of 9

5 Weight (g) Ephemeroptera Plecoptera Trichoptera Heteroptera Odonata Chirononmidae Coleoptera Diptera Oligochaeta Gammarus/assellus Mollusca Stones/fines Organic Fibrous Matter Digested Matter Non Organic Detritus Fish Empty Annelida Frequency Loughs Agency Escaped rainbow trout Management, Operational Plan, April Length weight relationship of all rainbow trout from Angling Survey (n = 485) y = 1E-05x R² = Length (mm) Page 5 of 9

6 Frequency Loughs Agency Escaped rainbow trout Management, Operational Plan, April Length frequency distribution of all rainbow trout caught in Angling Survey (n=485) Length (mm) Page 6 of 9

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