Reproductive ecology and dispersal potential of varnish clam Nuttallia obscurata, a recent invader in the Northeast Pacific Ocean
Bibliographic record
Abstract
The fecundity, larval development, and temperature and salinity tolerances were determined for the varnish clam Nuttallia obscurata (Reeve 1857), a recently introduced species in the Northeast Pacific. Adult varnish clams from 2 populations were collected in British Columbia, Canada throughout the spawning season to determine sex, fecundity, and timing of spawning. Adult varnish clams were also spawned in the laboratory and the larvae reared at a range of temperatures and salinities. The highest larval growth rates were observed in the 20°C and 20 psu treatments. Planktonic duration ranged from 3 to potentially 8 wk, with higher temperatures and salinities resulting in a shorter planktonic phase. Larvae reared at 9°C, and at 10 and 15 psu, grew slowly and survived for a minimum of 1 mo but did not reach metamorphosis. These results indicate that varnish clam larvae have a wide range of salinity and temperature tolerances, but grow optimally at warmer temperatures and higher salinities. Varnish clams have comparable larval environmental tolerances and spawning duration to co-occurring bivalves. However, their fecundity appears to be slightly higher and they reach sexual maturity earlier, potentially providing an advantage in establishing new populations. The lengthy planktonic phase, combined with favourable oceanographic circulation patterns, has contributed to the rapid dispersal and geographic range expansion of the varnish clam in the Northeast Pacific.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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 teacher head, 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".