Behavior and survival of hatchery reared advanced fingerling largemouth bass using radio telemetry. Brandon Thompson

Transcription

1 Behavior and survival of hatchery reared advanced fingerling largemouth bass using radio telemetry Brandon Thompson

2 Florida largemouth bass Micropterus salmoides floridanus Premier freshwater sportfish 60% of all angler days 1.3 billion dollars

3 10 Lake Griffin EF L/F 2007 Percent frequency Age 1 bass Length (1-cm)

4 10 Lake Griffin EF L/F 2007 Percent frequency Age 1 bass Length (1-cm) Percent frequency Age -1 bass Healthy Recruitment L/F Length (1-cm)

5 Florida Bass Conservation Center Completed February ,000 SF Production Bldg High production capabilities 1.5 million fingerlings 1 million advanced fingerlings

6 Fingerlings New systems, fish kills, renovations Stocking Advanced fingerlings Supplemental stocking Augment natural recruitment Recruitment limited systems Can produce high contribution Lake Talquin (live reared)

7 Advanced Fingerling Larger size (~ 4 inch) Traditional fingerlings; 1-2 inch Raised on pellets (high production) Higher survival Piscivorous New Culture techniques Improved artificial feed Release techniques Transition to live prey Out of season spawning

8 Stock Enhancement Project Ocklawaha chain selected as research system Stock Lake Griffin for 3 years and track contribution Stock Lake Carlton as research lake for radio telemetry

9 Why use radio telemetry? We know very little what stocked fish do after release Behavior Survival Movement and dispersal Habitat use

10 Radio Tag Selection ATS model A2414 (0.24 g) - 2% rule Expected battery life 30 d Range, accuracy, detection Smallest transmitters ever used in a fisheries study!

11 Surgical Techniques Smallest fish tagged in a study Adopted from USGS Shielded needle technique Specialized tools Fish seemed to recover well from surgery Entry hole for transmitter Exit hole for antenna

12 Tag Effect Studies Radio tagging small bass/hatchery bass Affects unknown from tagging Assumptions of Telemetry Tagged fish represent untagged Growth and predator avoidance Similar to untagged

13 Telemetry Site: Lake Carlton 400 acre lake on 76,000 acre chain Representative habitat Habitat mapping ArcMap Vegetation polygons Fish locations overlay Movement analysis Habitat analysis Bulrush

14 2009 (May 18) Tagging - 50 hatchery fish tagged Stocking Stocked ~ 11,000 hatchery fish along with tagged fish both years 2010 (March 30) - 30 Hatchery bass - 20 Wild bass Focus on 2010 comparison

15 Tracking Methods Tracked all fish daily Stationary receiver in canal Fish located and data recorded Locations with GPS Depth, vegetation, environmental

16 Survival and Predators

17 Results - Survival Confirmed fish deaths: 16 Hatchery 14 (Predation; fish and birds) Wild 2 (tagging mortalities) 14 and 30 Day Survival Wild had significantly higher survival 62% 90% 82% 38%

18 Normal hatchery fish movement? Single fish locations through 14 days

19 High Movement Fish Fish #14

20 Movement Dispersal > 5/30 (17%) of hatchery fish left Lake Carlton (0 wild fish) Movements Range: (6 miles!) Record movement (24 hrs) = 1.8 miles 700 Dispersal 100 Movement Per Day Meters Hatchery 21-day Wild 21-day Meters Hatchery Wild day 14-day 21-day

21 All fish locations

22 Fish # 38 Offshore Hatchery Fish

23 Habitat Selection - GIS Proportion of locations used Offshore Submersed Grasses Bulrush Cattail 2010 Hatchery 2010 Wild

24 Growth 0.6 Growth - mm/day 2.5 Growth - % body weight mm per day hatchery wild % Body weight per day Hatchery Wild

25 Discussion Differences b/t hatchery and wild Domestication effects (raceways, pellets) High movements Non-complex habitat selection Slow growth Equals predation Led us to study acclimating pelletreared fish to the wild

26 Post-Stocking Survival of Naïve vs. Conditioned Hatchery-Reared Largemouth Bass

27 Can post-stocking survival be increased through conditioning? Condition one batch of fish to the natural photoperiod, habitat, predators, and forage in an earthen pond Compare survival of conditioned fish to those straight from the raceway

28 Conditioning ½ acre conditioning pond: 10 days Predators: bass and bowfin Forage: mosq fish Cover: 10 brush piles

29 Research Ponds Four 1-acre ponds Community structure stocked 10 brush piles (standardized habitat) Ponds stocked with both conditioned and naïve fish Trial run 30 days and harvested

30 Survival Pond 21 Pond 22 Pond 28 Pond 29 Mean for 4 ponds combined Percent Survival naive conditioned 10 0 P = 0.001

31 Conditioned fish Mean Total Length (mm) Pond 21 Pond 22 Pond 28 Pond 29 Mean for 4 ponds combined naive conditioned naive 80 P < 0.01

32 Discussion Nearly doubled survival in research ponds Faster growth post stocking Improved foraging and predator avoidance (tank experiments) Translate to natural lakes? Acclimating production #s?

33 Objectives Small lakes stocking study 1. Survival of phase II bass with high replicates Stock 11 lakes spring 2012 (50/acre) All fish tagged (MWT) Evaluation spring 2013 (age-1) and 2014 (recruit to fishery) with pop est. 2. Compare survival b/t raceway fish and those conditioned in predator free nets Stock spring of 2013 Condition in-lake for 5 days Evaluate spring 2014

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35 Anticipated results Survival information for managers to make informed stocking decisions Determine survival differences by in-lake conditioning Will survival increase and improve stocking success

36 Is Stocking the Answer??? What do we recommend based on data?

37 Ocklawaha Chain of Lakes bass update Long Term Monitoring Standardized beginning 2007 Spring electrofishing Catch rates Size structure Relative weights Angler surveys Lake Harris Lake Griffin Exploitation Future sampling

38 Monitoring bass populations Small lakes Mark-recapture population estimates Large lakes Relative abundance Catch per unit of effort

39 Monitoring bass populations 12 Relative abundance (Catch rate) Abundance

40 Relative abundance Catch rates

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42 Spring bass electrofishing Bass catch per 15 minute transect > 9" < 9" 0 Eustis Harris Dora Griffin Beauclair Apopka

43 50 45 Catch rates Catch per 15 minute transect Apopka Griffin Harris Dora Eustis Beauclair

44 35 30 Griffin Catch per 15 minute transect

45 30 25 Griffin Catch per transect Griffin Vegetation Acres of vegetation

46 30 25 Griffin Catch per 15 minute transect Catch rates Success Catch per hour

47 35 30 Beauclair Catch per 15 minute transect

48 35 30 Apopka Catch per 15 minute transect

49 35 30 Harris Catch per 15 minute transect

50 35 30 Dora Catch per 15 minute transect

51 55 Eustis 45 Catch per 15 minute transect

52 Catch of Age-1 Bass Catch per 15 minute transect Dora Eustis Apopka Harris Griffin Beauclair

53 Dora and Apopka Age Catch per 15 minute transect Dora Apopka

54 Griffin and Harris Age Catch per 15 minute transect Harris Griffin

55 20 Eustis Age Catch per 15 minute transect

56 Percent frequency Percent frequency 10% 9% 8% 7% 6% 5% 4% 3% 2% 1% 0% 10% 9% 8% 7% 6% 5% 4% 3% 2% 1% 0% Griffin 2007 Age-1 bass Griffin 2012 Age-1 bass Inch group

57 Percent frequency Percent frequency 10% 9% 8% 7% 6% 5% 4% 3% 2% 1% 0% 10% 9% 8% 7% 6% 5% 4% 3% 2% 1% 0% Eustis 2007 Age-1 bass Eustis 2012 Age-1 bass Inch group

58 10% 9% Dora % 7% 6% 5% 4% 3% UF Wild 2% 1% 0%

59 105 Condition of Bass (Relative Weights) 100 Eustis Relative Weight Dora Beauclair Harris Griffin Apopka State average

60 30 25 Griffin Catch rate Wr Catch per transect Condition

61 Lake Harris Creel Largemouth bass Hours 43,872 50,407 Catch 15,435 26,153 Success Fisheries managers target 0.25 as goal for quality fishery Anglers: 87% fish from boat 78% resident 32% bass tournament

62 Griffin Exploitation 300 fish tagged in lake and canals high rewards Year 1 Caught 20% (60/300) Removed - 2.7% (8/300) Fishing mortality of little concern for population Recruits and habitat! Number Griffin Tag Returns Not Caught Fish Caught

63 Are we there yet? #1 freshwater fisheries problem in FL Habitat degradation Ock. Chain We ve seen improvements not recovered Long way to go Where are those improvements - learn from them replicate Submersed Veg Water fluctuations

64 Sampling for Fall community sampling Spring bass sampling Fall trawling for crappie Angler surveys Griffin evaluate crappie rule change Eustis Long term monitoring Apopka Use study as baseline for restoration Study to assess the effects of fishing nesting bass Will include Lake Eustis