Santa Cruz Island Reserve

22 May, 05 AM - 28 May, 02 AM

Previous studies have found a strong nocturnal drift pattern in streams inhabited by fish. In the absence of fish, drift is fairly uniform. Nocturnal drift may be related to increased insect activity at night, which is in turn related to avoidance of visual predators (fish). Nocturnal drift patterns can be induced in “fishless” streams with the introduction of fish. Historically, the streams of Santa Cruz Island (SCI) have lacked fish. Previous sampling indicates aperiodic drift in SCI stream. This summer, we will continue to monitor baseline drift patterns in Christy Stream by collecting 5 macroinvertebrate samples from Christy Stream at 4 hour intervals. These samples will be preserved in 70% ETOH and removed from the island for processiong. As it would be inappropriate to introduce fish into SCI streams to test nocturnal drift inducement, I hope to develop behavioral assays to determine whether or not changes in macroinvertebrate behavior occur when exposed to fish odor in water in a controlled environment. The fish odor will be obtained by euthanizing the trout. Five trout will be euthanized via overdose of MS-222 and five trout will be euthanized by bubbling compressed carbon dioxide into the water. Following euthanzasia, the trout will be preserved in ethanol. Fish exudates collected from the ethanol will be used for the behavioral assays. Additional behavioral assays will be conducted using water collected from the fish hatchery.* Eventually, I hope to develop a drift inducement study using fish exudates and comparing the effectiveness of exudates inducing nocturnal drift in “fishless” mainland and island streams. The implications of this study will be related to the possible behavioral changes that may have evolved in the relatively isolated island macroinvertebrate populations as compared to the mainland. Location of Field Work: Christy Stream (near bunk-house) Populations affected: Stream macroinvertebrates Requested resources: housing at Christy Ranch, pick-up truck Experimental Design: Collection of 5 drift samples at 4-hour intervals over a period of 5 days; macroinvertebrates collected in drift nets will be stored in ethanol for later processing (off-island; macroinvertebrate behavioral assays will be conducted in the Christy bunkhouse. Impacts: 1. Placement of drift nets in streams should not result in negative impacts in streams; 2. IACUC form for trout euthanasia has been filed with UCSB. 3. At no time will the trout come into contact with SCI surface water. In addition, water from the hatchery will not come into contact with island streams or soils. Containers of hatchery water will be held in ice chests during transport. Behavioral assays will preformed indoors and in a plastic tub. Equipment used in the behavioral assays will be held in a plastic tub. Following the behavioral assays, hatchery water will be disinfected by addition of bleach (final solution = 15% bleach) and removed from the island. All materials that come into contact with hatchery water (containers, forceps, nets) will be rinsed in a solution of 30% bleach. Likewise macroinvertebrates used in the behavioral assay will not be returned to the stream, but will be preserved in 70% ethanol and removed from the island.

Visit #1389 @Santa Cruz Island Reserve

Approved

Under Project # 1161 | Research

Furlong - Stream Drift

faculty - Northwestern College

Reservation Members(s)

Laura Furlong May 22 - 28, 2003 (7 days)
Group of 4 Undergraduate Student May 22 - 28, 2003 (7 days)

Reserve Resources(s) | Create Invoice

Dorm 5 May 22 - 28, 2003
Pickup Truck 5 May 22 - 28, 2003