Grazing rates and feeding preferences of the mysid shrimp Gastrosaccus brevifissura in a temporarily open estuary in South Africa
Bibliographic record
Abstract
Gastrosaccus brevifissura is a key crustacean species in most South African estuaries. The biomass, distribution, grazing rates and feeding preferences of this species were investigated in the Mpenjati Estuary, on the east coast of South Africa. The species exhibits a very marked diurnal migration behaviour, with biomass varying within the range 0.005 to 0.26 g m -3 dry wt (DW) during the daytime and 0.002 to 1.53 g m -3 DW during the night. The estimated total population grazing impact of the mysid ranged between 22 and 32% of the available phytoplankton in summer and winter, respectively. This suggests that G. brevifissura may not meet all its metabolic demands by consuming phytoplankton alone. Other possible food sources available in the estuary include plant detritus (DTR), microheterotrophs and benthic microalgae (BMA). In particular, the vertical migration behaviour of G. brevifissura allows close spatial association with the benthic microalgae during most of the day. Indeed, feeding experiments suggest that G. brevifissura is able to feed efficiently on settled as well as on resuspended benthic microalgae. This is supported by results from stable isotope analysis ( 13 C and 15 N), which show that benthic microalgae contribute 68 and 24% to the total diet of G. brevifissura in winter and summer, respectively. This also suggests that other food sources are needed by this species to meet all its energetic demands. Carbon rations obtained from in situ grazing methods are 35 to 44% (winter) and 1.6 to 3.9% (summer). When these values are compared to the previously estimated basal metabolic requirements for the mysid, it follows that G. brevifissura is able to meet all its energetic requirements from a pure autotrophic diet only during the winter. On the other hand, during summer, these values are barely enough to meet the basal metabolic rate of this species.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.002 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".