WSP09538

• File Number: 8240.300.10
• Description: San Juan Recovery Implementation Program
• Basin: San Juan/Dolores
• Date: 10/12/2000
• Author: SJRIP
• Title: San Juan River Basin Recovery Implementation Program Final Annual Budget and Work Plan Fiscal Year 2001
• Water Supply Pro - Doc Type: Publication

San Juan River Larval Fish Passive Drift-Netting
Fiscal Year 2001 Project Proposal

Principal Investigators: Steven P. Platania
Division of Fishes - Museum of Southwestern Biology
University of New Mexico
Albuquerque, NM 87131
[phone] [e-mail]

I
I
I

and

Co-principal Investigator: David L. Propst
Conservation Services Program
New Mexico Department of Game and Fish
State Capitol, ViIlagra Bldg, P,O, Box 25112
Santa Fe, NM 87504
[phone] d"[e-mail]

Backl:round:

Beginning in spring 1995, personnel from the Division of Fishes, Museum of Southwestern Biology (MSB), at
the University of New Mexico assumed responsibility for the San Juan River larval fish passive drift-netting
study. This project, fonnerly conducted by the Utah Division of Wildlife Resources, continued with only minor
changes in sampling protocol. Data collected from this research activity provided several discrete types of
infonnation on the fishes of the San Juan River. Data that can be obtained on the endangered fishes of the river
include detennining approximate spawning period, identifying approximate location of spawning sites, and
assessing effects of annual hydrology (and temperature) on their reproductive activities. Similar data could also
be obtained for other members of the ichthyofaunal community and contrasted with previously drift-net
sampling to assess the effects of that year's flow regime on fish reproduction. Samples collected during this
research program were and will continue to be processed and curated by Fish Division personnel at the
University of New Mexico.

Since the initiation of this research program, five larval Colorado pikeminnow have been collected, The two
YOY Colorado pikeminnow collected in 1993 (at Mexican Hat) were the same length (9.2 mm TL; MSB
18098, 18099) and were taken on consecutive days in late July (26-27), From these two individuals, we
detennined the date of spawning to be about 8-9 July 1995,

Two larval Colorado pikeminnow were taken at Mexican Hat during the 1995 larval fish passive drift-netting
study. The first specimen, 9.5 mm TL meso larvae (MSB 26187) was taken between 2114-2310 hours on 2
August 1995, The next morning (3 August 1995) between 0531-0800 hours, a second Colorado pikeminnow,
9.0 mm TL mesolarvae (MSB 26191) was collected. The similar size and developmental stage of these two
individuals, in combination with the fact that the two fish were collected within 12 hours of each other, strongly

9

~