Evidence of selection for resistance to paralytic shellfish toxins during the early life history of soft‐shell clam, <i>Mya arenaria</i>, populations
Bibliographic record
Abstract
This study identifies early, postmetamorphic soft‐shell clams, Mya arenaria, as the life‐history stage most susceptible to effects of blooms of paralytic shellfish poisoning (PSP) toxin–producing Alexandrium spp. Laboratory experiments used progeny from predominantly susceptible (naϊve) or resistant (annually exposed) NW Atlantic populations. Growth and survival of toxified veliger larvae did not differ from those fed nontoxic algae. In contrast, postlarvae (4–12‐mm shell length) from both populations exposed to a highly toxic Alexandrium tamarense isolate (~ 100 cells mL−1, 64–69 pg saxitoxin equivalents [STXeq] cell−1) suffered burrowing incapacitation, toxin accumulation, and mortalities within 1 week of toxin exposure. These effects were greater and occurred sooner in the naϊve population. Short‐term toxification in the laboratory caused a significant shift in the genotypic composition of this population, determined with a molecular marker for sodium‐channel resistance. Clams with the sensitive genotype were selectively eliminated relative to resistant or heterozygote clams. Ingestion of toxic cells (too large for larval capture) is thus required to elicit toxic effects. Exposure to mixed, toxic, and nontoxic algal suspensions demonstrated that adverse effects to fitness (survival and growth) were dose‐dependent, occurring only at ≥ 50 cells mL−1 of the isolate used (PR18b). Paralysis and thus increased predatory risk occurred even at 10 cells mL−1. Postlarvae < 12 mm, which can co‐occur with red tides throughout the Atlantic range of M. arenaria, were more susceptible to PSP than large (> 30 mm) juveniles. Natural selection for resistance in Atlantic populations will thus vary latitudinally with the timing, duration, and intensity of toxic blooms.
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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 | 0.000 | 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".