Observations of handling trauma of Columbia River adult white sturgeon, Acipenser transmontanus Richardson, 1836, to assess spawning sanctuary success

Abstract

Summary A sanctuary targeting the time and space occupied by reproductively active white sturgeon, Acipenser transmontanus, during spawning can be an effective method for reducing angling‐related stressors. A catch and release (C&R) fishery targeting over the legal limit (oversize; ≥137 cm fork length) white sturgeon had been intensifying since 1990 and grew in popularity through the 2000s in the lower Columbia River. A research project to describe the reproductive structure of the adult white sturgeon population below Bonneville Dam (rkm 220‐233) was initiated in 2000 and provided the first detailed observations of trauma linked to this C&R fishery. Fish captured from 2003 to 2011 were examined for evidence of in‐season angling damage (hook marks, leaders and lines in buccal cavity) from June through August each year. Carcass surveys were conducted weekly from June through August within a 24.8 km stretch downstream from Bonneville Dam. Catch rates were determined through angler interviews and aerial counts of boat and bank anglers. Four major regulation changes occurred during the course of the study affecting the seasonal spawning sanctuary in space and time. A total of 679 oversize white sturgeon were examined for evidence of in‐season angling damage. The proportion of individuals with evidence of angling, damage indicators per individual, number of carcasses found and the number of carcasses with observed evidence of angling or retained gear, and the total number of oversize fish handled by boat anglers declined after each fishing regulation change. The trends suggest that the sanctuary influenced the number of encounters between anglers and white sturgeon and that increases to the sanctuary in time and space reduced stress endured by oversize white sturgeon.

Identifying monitoring information needs that support the management of fish in large rivers

“…For data collected by monitoring programs to have the highest relevance, the spatial and temporal scales appropriate for scientific investigation and management must also be time and geographiccontext specific. For example, the management of White Sturgeon (Acipenser transmontanus) in the Columbia River varies by reservoir or river segment and season [40,41]. The effects of hydropower development on White Sturgeon vary spatially and temporally as well, so the spatial and temporal context of the data needed to understand the effects needs to be considered.…”

Incidence, Types, and Shedding and Ingestion Times of Metallic Fishing Tackle in the Digestive Systems of White Sturgeon

“…; Halvorson et al. ). The apparent lack of deep hooking in White Sturgeon fisheries coupled with the knowledge that metal ingestion is relatively common suggests that the ingestion does not stem directly from angling but rather indirectly, with White Sturgeon presumably ingesting baited hooks that have broken off on the river bottom (Lamansky et al.…”

Corrosion Rates and Compression Strength of White Sturgeon‐Sized Fishing Hooks Exposed to Simulated Stomach Conditions

“…In the Hell's Canyon reach of the Snake River in Idaho, an estimated 15% of White Sturgeon Acipenser transmontanus have angling tackle in their digestive system (Idaho Power Company ), and the presence of such metal has been documented in many other sections of the Snake and Columbia rivers (Idaho Power Company ; Halvorson et al. ). However, deep hooking while fishing with bait for this benthic‐feeding fish appears to be extremely rare (i.e., 0.5%: Lamansky et al.…”