Use of Fishes for Control in

Michael V. Saba Assistant Biologist Pupfishes Toothcarps (Poecilia reticulata) (Apphanius mento) (Valencia hispanica)

Ricefishes Rivulines Cichlids (Oryzias spp.) (Rivulus spp.) (Tilapia spp.)

Killifishes Gouramies Rainbowfishes (Fundulus parvipinnis) (Betta splendens) (Melanotaenia spp.)

Mosquitofish Feeding

Why Use Mosquitofish?

 Consume mosquito larvae

 Reproduce quickly

 Highly resilient

 Easy to maintain & rear

 Reduce pesticide applications Mosquitofish History

• 1904: Mosquito larvivory observed

• 1920: Mosquitofish implemented

• 1920 – Present:

– Many Studies

– Polarized views

David Starr Jordan Mosquitofish 101

♀

♂ affinis (Western Mosquitofish) Gambusia holbrooki ()

http://www.natureserve.org Mosquitofish Stocking Sources

• Immediate control necessary • Areas having high larval abundance • Seasonally flooded or isolated features • Habitats with poor water quality Mosquitofish Stocking Restrictions

• Not suitable in sensitive habitats • Native provide comparable control • Possible adverse impacts on native biota • Possible adverse impacts to other non-target biota • Potential food web impacts Alternatives: Native Fishes Selection Criteria

• Preference for immature (e.g., larvae and pupae)

• “-sized” 2-5 cm (~1-2 in.)

•Higgph reproductive rate Native Fish Candidates (CA)

Arroyo Chub Sacramento Blackfish

Hitch California Roach

Three-spine Stickleback

Sacramento Perch Native Fishes (Orange County)

Arroyo Chub Threespine stickleback

Santa Ana sucker

Steelh ead

Speckled dace The Candidates

Gila orcutti Gasterosteus aculeatus microcephalus

• Native to CA and OC • Native to CA and OC • Omnivorous • Planktivore/piscivore • 120 mm SL •3-5 cm TL • Oviparous • Oviparous • CA Spec ies o f Spec ia l Concern Important Considerations

 Maintainance and rearing of fishes

 Stocking locations

 Historic and current distributions

 Stakeholders and collaborations

 Population genetics

 Disease transmission

 Pitd/MOUPermits and/or MOUs OCVCD Proposal Advantages

 Alternative in sensitive habitats

 Environmental stewardship and enhancement

 Reduce pesticide applications

 Provide information to scientific community Thank You!

• Dr. William Walton • Greater LA VCD • Roy Leidy • OCVCDOrange County VCD • Dr. Jon Baskin • Contra Costa MVCD • Dr. Camm Swift • Sacramento Yolo MVCD • Kerwin Russell • Coachella Valley MVCD • Richard Zembal •USGS • Dr. Peter Moyle • CDFG • Sharon Keeney • Natural History Museum of LA • Dr. Donovan German County •Dr. Mike Horn