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THREATENED & ENDANGERED FISHES ripened or good eggs cannot be obtained. Eggs force-ovulated prior to the spawning peak, or taken afterward, have low viability. This requires close monitoring of female brood fish to ensure procurement of viable eggs. I Female Colorado squawfish are injected with carp pituitary (CP) to induce ovulation of matured eggs. Hamman (1981b) determined that two mg CP per pound of body weight injected intraperi- toneally was the appropriate hormone, dosage, and method of injection for female Colorado squawfish. Male Colorado squawfish normally stay ripe and fluid, but receive intramuscular injections of CG at 150 IV per pound of body weight if fluidity deheases. Colorado squawfish are spawned utilizing the wet method, as described for razorback suckers. Eggs are "c1ayed," rinsed, water-hardened, enum- erated, and incubated in Heath trays and jars. At 70 F, Colorado squawfish eggs hatch between 96 and 144 hours, with peak hatching at 120 hours. Following swim-up, fry are stocked in ponds at the same rate as razorback suckers. Hamman (1986) reported that Colorado squaw- fish spawned during 1983 and 1984. In 1984, nine domestic Colorado squawfish females averaging 3.2 pounds produced 20,656 eggs per pound of body weight. Feed conversion was 3.90 for Col- orado squawfish fingerlings in 1984. Of all the large native Colorado River fishes, the bony tail has come the closest to extinction. Apparently, only a few old fish remain in the lower basin (W. L. Minckley pers. comm.), and only an occasional collection has been made in , the Gray Canyon area of the Green River in the upper basin (Tyus et aI1982). Extel,lsive collecting efforts during the past 11 years, to obtain bony tails for culture purposes, has produced only 24 fish and all of them are now dead. Hamman (1982) successfully spawned bony tails at Willow Beach NFH in 1981. Some of the fry were reared at Dexter NFH and now constitute a captive-held brood stock. Spawning trials on two-year-old bony- tails were carried out in 1983 (Hamman 1985). Bony tails are also long-lived. Recent age deter- minations of two Lake Mohave specimens, from otoliths, by Bruce Taubert (pers. comm.), AG&F, placed their ages at 40 to 42 years. During May, 1983, 24 female bony tails were spawned over a four-week period, utilizing CP to induce egg ovulation (Hamman 1985). Spawning and hatching techniques identical to those reported for Colorado squawfish were utilized, except that jars were not tested. The fish ranged from 0.1 to 0.5 pounds, with a mean weight of 0.28 pounds.: Fecundity ranged from 1,015 to 10,384; mean fecundity was 4,677. Average number of eggs per pound of body weight varied from 5,075 to 29,930, with a mean of 17,280; egg viability averaged 67.5%. Eggs were hatched in Heath incubators at 70 F, and the fry were distributed to the AG&F and the California Department of Fish and Game. No fingerlings were reared at Dexter NFH. Woundfin spawning was examined in 1984. Both natural and hormone-induced spawning were at- tempted. Greatest success was achieved through natural spawning on a prepared gravel bed (size range 114 in to 5 in). Current was provided by flowing water passing through a plugged 2-in black plastic pipe with 1I8-in holes drilled in it to pass water somewhat uniformly over the gravel bed. Seventy adult woundfins were placed in the spawn- ing pond and 64 were brought to the holding house for spawning studies. Sexing woundfins was dif- ficult; no technique was fully reliable. Males av- eraged 4.97 grams and were injected with CG to enhance milt production. Twenty females (aver- aging 6.44 gms) from the lot of 64 fish were injected with CP to induce egg ovulation, and were hand-stripped 24 hours later; twelve (60%) spawned successfully. Total fecundity was 2,067 and mean fecundity 172. A total of 1,163 swim- up fry were recovered and stocked, along with fry produced by natural reproduction in the ponds. A total of 3,500 woundfins were recovered in late summer. Altogether, between 1981 and 1984, Dexter NFH personnel distributed 6,108,965 fry and 296,376 fingerling razorback suckers, and 116,638 Colorado squawfish fingerlings into historic hab- itats in Arizona and Colorado, respectively. Other transplants include bony tail , Yaq\lichu~, Gila topminnow, and desert pupfish. ' The current status of these native fishes of the American Southwest can be attributed directly to man's activities, primarily habitat alteration. Re- covery of these unique fishes now requires well ' planned and determined human action. Protec- tion, habitat preservation and management, re- search, captive propagation, re-introduction, and public education are all essential components of recovery programs. With no evident recruitment to declining razorback sucker and bony tail pop- ulations, the long life spans of these species are obviously all that have saved them from extinction up to now. Many other species persist precariously in limited habitats. Hopefully, the described re- covery efforts will not only preserve and perpet-