Status of White Sturgeon in the Lower Fraser River, British Columbia
Bibliographic record
Abstract
ABSTRACT Sturgeon (Acipenseridae) stocks worldwide are generally in decline, with many populations close to extirpation. One prominent species, the White Sturgeon (Acipenser transmontanus) with spawning populations distributed throughout three large, western North American watersheds (the Sacramento, Columbia, and Fraser rivers), has experienced population declines in the past decade. In 2003, the Committee on the Status of Endangered Wildlife in Canada designated all six populations of White Sturgeon in Canada “endangered.” To assist sturgeon recovery initiatives in the lower Fraser River (British Columbia), a stewardship-based monitoring and assessment program was developed by the Fraser River Sturgeon Conservation Society. A descriptive population model was developed to provide reliable annual population estimates by size/age group and location, based on tag release and recapture data collected by trained volunteers. As of January 2011, the population estimate (from 40- to 279-cm fork length) was 44,713 (95% confidence level 42, 634–46, 792). Group size analyses suggest that abundance decreases have been greatest for juvenile sturgeon under 100-cm fork length. Recruitment decline may be the result of several factors, including destruction of important spawning and early life history rearing habitats; fewer successful adult spawners due to in-river fisheries; and/or impacts of reduced food supply and ecological imbalances on both early life and adult stages. RESUMEN en términos generates, los stocks de esturiones (Acipenseridae) alrededor del mundo están reduciéndose, e incluso varias poblaciones se encuentran cerca de ser extirpadas. Una especie importante, el esturión blanco (Acipenser transmontanus), cuenta con poblaciones reproductoras que se distribuyen a lo largo de tres cuencas hidrológicas del noroeste americano (ríos Sacramento, Columbia y Fraser), sin embargo ha experimentado reducciones poblacionales en la última década. En 2003, el Comité sobre el Estatus de la Vida Salvaje en Peligro, en Canada, designó a las seis poblaciones de esturión blanco el estado de “amenazadas”. La Sociedad para la Conservación del Esturión en el Río Fraser desarrolló un programa de evaluación y monitoreo con el fin de apoyar las iniciativas de recuperación del esturión en el bajo Río Fraser (Columbia Británica). Se desarrolló un modelo poblacional descriptive para estimar anualmente, y de manera confiable, el tamaño de la población por grupo de talla y edad y por locación, sobre la base de datos de captura-recaptura colectados por voluntaries debidamente entrenados. La población estimada para el año 2011 (40–279 cm de longitud furcal) fue de 44,713 (95% de confianza 42,634–46,792). El análisis del tamaño por grupo indica que la reducción de la abundancia ha sido más importante en los juveniles de esturión de menos de 100 cm de longitud furcal. El decremento del reclutamiento puede ser el resultado de varies factores que incluyen la destrucción del hábitat de desove y desarrollo de los primeros estadios de vida de la especie; poca abundancia de adultos desovadores debido a la pesca en los ríos; y/o los impactos que tienen la reducción de alimento y otros desbalances ecológicos en los adultos y en los juveniles.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".