Rockfish On Oil Platforms

Translocation and homing behavior of rockfishes from oil platforms in the Santa Barbara ChannelKim AnthonyChris LoweCalifornia State University Long BeachMilton LoveMarine Science Institute, University of California Santa Barbara

1

Last 20 yrs local populations and species are being overexploited (Lea et al. 1999)FisheryRecreational and Commercial important for >100 yrs. (Lea 1992)in CA, historical value >$1B/yr (Lenarz 1986)severe declines since late 1970s

images from sportfishingreport.com

2Scan Miltons pic

Oil Production Platforms Platforms have a limited life expectancy and must be decommissionedIn CA, only option is total removal

3

Delta Sub SurveysDeepwater sub surveys (Love et al. 2003)Higher densities of overexploited species on platforms vs. natural reefs of comparable depthsSome species more often on platforms than on natural reefs oil platforms function as de facto marine reserves

4

Decommissioning & MitigationExplosives fatally concuss all fish with swim bladder around platform (Bull & Kendall 1992)Decommissioning process removes habitatMitigate effects of decommissioning in CAtranslocate fish from platformsalvage platform-associated rockfish/groundfishseed nearby natural reefsimplications to resource management decisions

5

Rockfish Movement Previous displacement experimentsYellowtail: 22.5 km (Carlson & Haight 1972)Copper, quillback, brown: 3.2 8.0 km (Matthews 1990)Lingcod / 2.8 km (Matthews 1992) Site fidelity study 2004-2006 (Lowe et al. in review)Fidelity to platforms highly variable across species and among individualsMovement between platforms (5-6 km)

6Yellowtaildisplaced and returnedCopper and quillback500 m displacement from high to low relief habitatNot unreasonable to predict movement back to platforms.

Goals Tag 80 platform-associated groundfishes Translocate them to Anacapa Island Marine Reserve Determine homing events and differences among species Assess movement patterns HA: Translocated fish will home back to oil platforms from Anacapa even if provided with suitable habitat of comparable depth

7

Acoustic Telemetry 101

Code Receiver DetectionDate DetectionTime 3790 4454 9/01/2006 12:34:20

8

Telemetry Data Homing: fish released at Anacapa leaves and returns to its platform of capture Time to travel: the time lapsed between the last detection at Anacapa and the first detection at a platform Patterns of movement: determined when fish detected on >1 VR2

9

225 m 64 m90 m

10

Receiver Deployment: oil platforms

z = 84 mz = 54 m

Receiver Deployment: Anacapa Island

12Habitat maps USGS

Tagging & Translocation

Fishing from three oil platforms: Gail (225 m), Gilda (65 m), and Grace (90 m).

13

Tagging & Translocation

Surgical implantation of acoustic transmitter.

14

Tagging & TranslocationReleased at surface with weighted milk crate to 40 m.

15

Tagging Summary (N=80)

27 cm29 31 cm24 - 28 cm28 cm27 34 cm27 31 cm29 44 cm24 36 cm35 cm30 37 cm51 cm74 94 cm

16Bigger legend, platform depths

Lingcod (OELO)Vermilion (SMIN)Copper (SCAU)Brown (SAUR)

To Gail 11 kmTo Grace 18.5 kmTo Grace then Gail 19.5 kmTo Gilda 17.5 km

Proportion of Homersn=9/10n=1/2n=11/38n=1/6GailGildaGraceGrace2 = 31.41 homing not randomOverall Homing Rate: 27.5%

Time to Travel5.9 d 18.1 d9.9 d (fastest 2 d)1.4 d ( fastest 10.5 h)n = 1n = 1n = 11n = 9

SMIN 3640, Grace Phase I

SMIN 3790, Grace Phase II

Conclusions to date HA: Translocated fish will home back to their oil platforms of capture Some spp. (lingcod, vermilion, copper, brown) capable of homingHoming distances farthest reported for vermilion, copper, brown, lingcod (e.g. Matthews 1990, 1992, Pearcy 1990, Lea et al. 1999, Starr et al. 2004)

23

Conclusions to date Management implicationsUse these fish as proxies for endangered species such as cowcod, yelloweyeMitigate effects of platform decommissioning in California?Yes and No for some spp., but individual variability need more insight on habitat assessment

24

Minerals Management ServiceSCTC Marine Biology FoundationDonald J. Reish Student Grant for Marine Bio RschRichard B. Loomis Research Award

Bonnie Jig Rogers, Ann Bull, Merit McCrea, Jeff Barr, Carlos Mireles, Kerri Loke, Scott Meckstroth, Gary Hurd, Corey Mead, Erica Jarvis, Tom Mason, Lewis Barnett, Chris Mull, Heather Gliniak, John de la Cuesta, Adel Rajab, Mike Sundberg

Southern California Marine Institute

Alvaro Monge, Computer Science & Engineering for database support

Pfleger Institute for Environmental Research (James Lindholm, Ashley Knight)Venoco Inc. (Joe Hollis, Jim Rickman, Tony Martinez, Vanita Menapace, Larry Mancini)DCOR LLC (Scott Robertson, Raoul Pena, Doug Archer, Jim Schulte) Ventura Harbor Master & Patrol (Scott Miller, Bobby Crane, Tim Burrows, George Kabris, Jon Freeman,John Higgins, Chris Emery) Daves Fuel Dock (Mark)

Tagging & Translocation

Caged at depth, released at 18 m the following morning.

26