9704

• UCREFRP Catalog Number: 9704
• Author: Ward, D., M. Childs and W. Persons.
• Title: Factors affecting growth of razorback sucker ‎(Xyrauchen texanus)‎ in captivity
• USFW Year: 2007.
• USFW - Doc Type: literature review and knowledge assessment.
• Copyright Material: NO

Abstract

The few remaining razorback sucker populations are sustained by captive rearing

and stocking programs. Captive-reared razorback suckers commonly experience high

predation when stocked into natural environments. This creates the need to rear fish to

larger sizes in captivity and to find new ways to improve growth for captive-reared fish.

We reviewed published literature and agency reports.for information on factors that affect

growth of razorback sucker. Site visits to razorback sucker production facilities and

surveys of fish hatchery personnel were conducted to obtain information on current

rearing practices. Razorback sucker growth is extremely variable and impacted by many

factors including fish size and age, sex, density, amount of living space, quality and

quantity of food, genetics and temperature. This makes evaluations of individual factors

that affect growth difficult. Culture practices for razorback suckers vary widely and

include differences in rearing environments, rearing densities, feeding regimes and types

of feed as well as grading or sorting practices. The focus at most razorback rearing

facilities is production, so the types of data that are collected are often insufficient for

detailed evaluations of rearing practices on growth. Calculated growth rates from the

literature vary widely and range from 0.2 - 1.8 mm/day. Typically the highest growth

rates are reported from natural or semi-natural pond environments. These growth rates

indicate that juvenile razorback suckers have a very high growth potential under ideal

rearing conditions. Detailed, replicated studies are needed to accurately compare the

effects of individual rearing practices on growth. These types of studies will ultimately

provide both time and cost-savings to production facilities by reducing the time it takes

for razorback suckers to reach stocking size, improving overall production efficiency.

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