Atlantic bluefin tuna spawn early to avoid metabolic meltdown in larvae

May combine two claims.

Survival (egg fitness) ultimately depends on predation mortality, which may be in the order of 0.6/day in early life stages of tuna.

“survival (egg fitness) ultimately depends on predation mortality, which may be in the order of 0.6/day in early life stages of tuna (Davis and Lyne 1991)”

• cites Davis and Lyne 1991 sourcePartly supported

  The Advection-diffusion-mortality modelling section estimates instantaneous mortality of 7–8-day-old southern bluefin tuna larvae at 0.66 per day, close to the claimed order of magnitude. It does not establish that this mortality was due to predation; it says starvation may also have contributed. The estimate concerns larvae, not egg survival or egg fitness. Page numbers are unavailable in our copy. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The temperature-food ration dependence is a logical and well known response in fishes, and recently also seen in a tropical larval tuna, but often ignored in predictions of thermal performance, phenology and spatial distributions.

“The temperature-food ration dependence is a logical and well known response in fishes (Brett 1979), and recently also seen in a tropical larval tuna (Gleiber et al. 2020), but often ignored in predictions of thermal performance, phenology and spatial distributions.”

• cites Brett 1979 sourceNot checked — no full text of the source
• cites Gleiber et al. 2020 sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

Similar conditions occur in the Gulf of Mexico, another main spawning area for ABFT.

“Similar conditions occur in the Gulf of Mexico, another main spawning area for ABFT (Landry et al. 2019).”

• cites Landry et al. 2019 sourceSupported

May combine two claims.

Heatwaves, such as the one in 2003, increase larval survival potential, but shorten the viable part of the season for the larvae.

“Heatwaves, such as the one in 2003, increase larval survival potential, but shorten the viable part of the season for the larvae.”

May combine two claims.

High temperatures benefit egg and yolk-sac stages, but the metabolic needs of feeding larvae are hard to sustain during the warmest periods.

“High temperatures benefit egg and yolk-sac stages, but the metabolic needs of feeding larvae are hard to sustain during the warmest periods.”

May combine two claims.

The availability of prey, particularly nauplii, is sufficient for fast growth in tuna larvae while temperature is moderate during midsummer, but not when temperatures increase later in summer.

“We find that the availability of prey, particularly nauplii, is sufficient for fast growth in tuna larvae while temperature is moderate during midsummer, but not when temperatures increase later in summer.”

May combine two claims.

During the heatwave in 2003, the predicted metabolic meltdown for tuna larvae occurred early, lowering the optimal temperature, and shifted optimal time of birth 2-4 weeks earlier in the season compared with cooler years.

“During the heatwave in 2003, the predicted metabolic meltdown for tuna larvae occurred early, lowering the optimal temperature, and shifted optimal time of birth 2-4 weeks earlier in the season compared with cooler years.”

May combine two claims.

An egg spawned at day 180 grows faster through the egg and first feeding phase, but slower as it approaches the post-flexion stage.

“An egg spawned at day 180 grows faster through the egg and first feeding phase, but slower as it approaches the post-flexion stage.”

May combine two claims.

At birthday 200, the temperature is high while Cladocera abundance plunges, and food intake does not support growth of larger larvae, leading to a metabolic meltdown where ingestion rates support metabolic needs, but not growth.

“At birthday 200, the temperature is high while Cladocera abundance plunges, and food intake does not support growth of larger larvae, leading to a metabolic meltdown where ingestion rates support metabolic needs, but not growth (Fig. 2c).”

May combine two claims.

An egg spawned at day 160 encounters a good food supply as a larva relative to its energetic needs, but also low temperatures and growth rates while they are small and vulnerable to predation.

“An egg spawned at day 160 encounters a good food supply as a larva relative to its energetic needs, but also low temperatures and growth rates while they are small and vulnerable to predation.”

May combine two claims.

These mechanisms create a peak in egg fitness in June/July (at about day 190) for this seasonal pattern in prey supply and temperature, and matches the actual spawning dates quite well.

“In summary, these mechanisms create a peak in egg fitness in June/July (at about day 190) for this seasonal pattern in prey supply and temperature, and matches the actual spawning dates quite well.”

May combine two claims.

Later in the season, temperatures increase and food intake cannot cover larval metabolic needs, and late offspring face a metabolic meltdown in which no energy is available for growth.

“Later in the season, temperatures increase and food intake cannot cover larval metabolic needs, and late offspring face a metabolic meltdown (sensu Huey and Kingsolver 2019) in which no energy is available for growth.”

May combine two claims.

As food supply increases, the optimal breeding time is progressively later in the season as potential for larval growth is higher under warmer temperatures.

“As food supply increases, the optimal breeding time is progressively later in the season as potential for larval growth is higher under warmer temperatures.”

May combine two claims.

Thermal tolerance in terms of hatching success is quite wide in ABFT embryos, and our model shows how food limitation can narrow the viable thermal range of feeding stages.

“In contrast, thermal tolerance in terms of hatching success is quite wide in ABFT embryos, and our model shows how food limitation can narrow the viable thermal range of feeding stages.”

May combine two claims.

Such interannual temperature variation affects egg fitness differently, depending on the level of food limitation: more food increases the threshold for metabolic meltdown, and then warmer water is beneficial to ABFT larvae.

“Such interannual temperature variation affects egg fitness differently, depending on the level of food limitation: more food increases the threshold for metabolic meltdown, and then warmer water is beneficial to ABFT larvae.”

May combine two claims.

For eggs in the main spawning period (days 170-190), the 2003 heatwave increased fitness by one order of magnitude compared with the cold 2004, while metabolic meltdown occurs earlier.

“For eggs in the main spawning period (days 170-190), the 2003 heatwave increased fitness by one order of magnitude compared with the cold 2004, while metabolic meltdown occurs earlier (Fig. 3b).”

Probably not a substantial claim: may not pass S4 (based).

If eggs and larvae grow according to their temperature potential, with no limits from darkness, digestion, or food, then relative egg fitness follows the temperature cycle.

“If eggs and larvae grow according to their temperature potential, with no limits from darkness, digestion, or food, then relative egg fitness follows the temperature cycle.”

May combine two claims.

Development of eggs and yolk-sac larvae are faster if temperature increases, but the first feeding larva needs abundant food supplies to grow fast.

“Development of eggs and yolk-sac larvae are faster if temperature increases, but the first feeding larva needs abundant food supplies to grow fast.”

May combine two claims.

The more food limited is the larval growth, the earlier is the egg fitness peak, as ingestion needed for growth increases with high temperatures later in season.

“The more food limited is the larval growth, the earlier is the egg fitness peak, as ingestion needed for growth increases with high temperatures later in season (Fig. 3a).”

May combine two claims.

Metabolic meltdown occurs at 22, 25 and 28°C if ingestion is 30%, 60% and 90% of body mass per day, respectively.

“Metabolic meltdown occurs at 22, 25 and 28°C if ingestion is 30%, 60% and 90% of body mass per day, respectively (Appendix S1: Fig. S5).”

May combine two claims.

The model matches this growth rate at c. 500 nauplii/m3, while the predicted peak in egg fitness remains within the observed spawning period.

“The model matches this growth rate at c. 500 nauplii/m 3 (Appendix S1: Fig. S4), while the predicted peak in egg fitness remains within the observed spawning period (Appendix S1: Fig. S3).”

May combine two claims.

The seasonal peak in egg fitness does not depend on the peak in Cladocera and is present even if both prey types are kept constant over time.

“The seasonal peak in egg fitness does not depend on the peak in Cladocera and is present even if both prey types are kept constant over time”

May combine two claims.

The seasonal peak in Cladocera suggests a classical match-mismatch driven phenology in ABFT, but the seasonally stable abundance of nauplii was more decisive for predicted phenology and growth of first feeding larvae in the model.

“The seasonal peak in Cladocera suggests a classical match-mismatch driven phenology in ABFT, but the seasonally stable abundance of nauplii was more decisive for predicted phenology and growth of first feeding larvae in the model.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Cladocera have a peak of abundance in the summer.

“particularly Cladocera, which have a peak of abundance in the summer (Atienza et al. 2016).”

• cites Atienza et al. 2016 sourceNot checked — no full text of the source

May combine two claims.

Atlantic bluefin tuna spawn while temperatures are rising, but before the heat leads to a metabolic meltdown in larvae.

“Atlantic bluefin tuna is a large, highly migratory marine top predator that spawns while temperatures are rising, but before the heat leads to a metabolic meltdown in larvae.”

Classified as probably not a substantial claim.

Seasonal cycles in prey availability and temperature interact to determine optimal spawning phenology.

“Therefore, seasonal cycles in prey availability and temperature interact to determine optimal spawning phenology.”

Classified as probably not a substantial claim.

The mechanistic model allows us to identify windows in spatial and temporal cycles of temperature and resources between which animals can migrate to ease physiological stress, reproduce or increase growth rates.

“The mechanistic model allows us to identify windows in spatial and temporal cycles of temperature and resources between which animals can migrate to ease physiological stress, reproduce or increase growth rates.”

May combine two claims.

The model does predict in situ larval growth with realistic prey abundances, and the predictions of spawning time compare well with observations.

“Despite these limitations, the model does predict in situ larval growth with realistic prey abundances, and the predictions of spawning time compare well with observations.”

Probably not a substantial claim: may not pass S4 (based).

Many tuna species spawn in the warm oligotrophic open ocean, where metabolic meltdown is a constant risk for the early life stages.

“Many tuna species spawn in the warm oligotrophic open ocean, where metabolic meltdown is a constant risk for the early life stages.”

May combine two claims.

The tolerance measured for larvae fed ad libitum may not reflect ecologically relevant temperature tolerance under food limitation and can be an overestimate for natural conditions.

“However, the tolerance measured for larvae fed ad libitum may not reflect ecologically relevant temperature tolerance under food limitation and can be an overestimate for natural conditions.”

May combine two claims.

These larvae appear to grow near the temperature maximum estimated by Reglero et al. (2018b), indicating these survivors were not limited by their food supply.

“These larvae appear to grow near the temperature maximum estimated by Reglero et al. (2018b), indicating these survivors were not limited by their food supply.”

• cites Reglero et al. (2018b)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

The Cladocera species in ABFT spawning areas are heat tolerant, and increased in abundance during the 2003 heatwave.

“The Cladocera species in ABFT spawning areas are heat tolerant, and increased in abundance during the 2003 heatwave (Atienza et al. 2016).”

• cites Atienza et al. 2016 sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

ABFT abundance increased after 2003, and the heatwave may have contributed to this.

“ABFT abundance increased after 2003, and the heatwave may have contributed to this.”