Modoc Sucker

Modoc suckers have short heads and small eyes. This sucker is mature when it reaches 3 to 4 inches (76 to 102 mm) long; the adult is usually no more than 7 inches (180 mm) long but it rarely exceeds 13 inches (330 mm). The largest Modoc sucker found in Goose Lake to date measured 11 inches (280 mm). Their lateral line scales count is usually 73 to 91.The average number of scales above the lateral line is 15 up to 19; the number of scales below the lateral line ranges from 9 to 12. It has been observed to reach five years of age at the oldest. Modoc suckers have 5 types of fins, which are dorsal, anal, pectoral, pelvic, and caudal. In detail, the number of dorsal fins ranges from 9 to 12 rays, anal fins from 7 rays, pelvic fins from 8 to 10 rays, pectoral fins from 15 to 17 rays, and caudal fins from 18 to 19 rays. The lower lip of Modoc Suckers is deeply notched and only one of the five to six rows of papillae connects the two lips. They have little yellowish-brown fins. Overall, they are greenish-brown or olive, and their backs are represented reddish color. Specifically, non-breeding body coloration of both sexes’ ranges from greenish brown to light blue to dark gray and olive. They have lighter coloration on the sides of the body with generalized mottling, usually with 3–4 darker spots similar in size to those of Sacramento suckers. …

This fish is limited to a few creeks in northern California and southern Oregon, where its historical range was located in the Ash Creek and Turner Creek drainages in the basin of the Pit River, the Goose Lake basin, which was once connected to the Pit River，as well as, the lower Cox Creek, approximately 6 km (3.7 mi) downstream of the Thomas's waterfall. It can currently be found in ten streams in this region. The current habitat range of the Modoc sucker is quite extensive, covering approximately 68.4 kilometres (42.5 mi) of water. This range significantly expands its earlier known range. In 1977, the known habitat of this fish was limited to seven streams in the Turner Creek and Ash Creek subbasins, totalling approximately 20.8 kilometres (12.9 mi).Remarkably, the present range encompasses virtually all of the known historical range of the Modoc sucker, with the sole exception of Willow Creek in the Ash Creek watershed, which appears to be outside of its habitat at this time. Modoc suckers primarily inhabit waters between 1,286 and 1,567 metres (4,220 and 5,140 ft) above sea level. The topography of this generation of waters ranges from flat to moderately undulating. The river flows south and meanders through the valley, diverging and converging in a series of creek valleys with numerous agricultural backwaters along the way. …

Specific physiological conditions need to be met for the Modoc sucker to reach sexual maturity and be capable of reproduction. Typically, both females and males must be over 12 centimetres (4.7 in) in length and at least three years old. These conditions ensure that the fish have sufficient physiological development to support reproductive activity. Occasionally, some individuals mature early, especially among males, a few fish reach sexual maturity at just two years of age. The spawning season for Modoc Suckers begins in mid-April and ends in early June, with the actual spawning period lasting only three to four weeks in different streams. Like other suckers, Modoc suckers migrate upstream during the spawning season and use intermittent tributaries to spawn. They are very selective about time, temperature, place, and current speed when spawning. In detail, they prefer to spawn on the bottom of fine to medium gravel ponds at water temperatures of 13.3 to 16.1 °C (55.9 to 61.0 °F) from midday to mid-afternoon, approximately 10:00 a.m. to 4:00 pm. Water flow in the creek during their spawning period generally varied from 42.7 to 56.8-liter per second. Spawning usually occurs in water 15 centimetres (6 in) deep. After selecting a suitable site, one female and usually three males, one on either side and one behind, complete the spawning behavior. …

The Modoc sucker has a diverse diet, with organic detritus, benthic invertebrates and algae as its main food sources. Diatoms and filamentous algae are common plant food items, while animal food items include larvae of the shaker mosquito, crustaceans, and larvae of aquatic insects, especially mayflies. The diet of the Modoc sucker changes as it ages. While the juvenile stage feeds primarily on organic detritus and algae, adults expand their diet to include the intake of chironomid larvae and other aquatic insects. This fish typically chooses to feed at the edges of slow-moving streams or at the bottom of ponds rich in detrital sediments and chironomid larvae. The dietary habits of the Modoc sucker are similar to those of the Sacramento sucker in Ash Creek as well as most species of the genus Catostomus.

Historical data does not contain specific information about Modoc sucker's cultural significance. There is also no direct evidence of people using the Modoc sucker for fishing activities as it was previously listed as endangered by the IUCN.

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