WR Sharks and fishes

Question 1

Atlantic Bluefin Tuna -the study

Answer 1

Migratory Movements, Depth Preferences, and Thermal Biology of Atlantic Bluefin Tuna

Block et al., 2001.

Study:

Used implantable archival and pop-up satellite archival tags to examine the movements, environmental preferences, and physiology of Atlantic Bluefin Tuna.

Question 2

Migratory Movements, Depth Preferences, and Thermal Biology of Atlantic Bluefin Tuna

Block et al., 2001.

The results

Answer 2

Results:

· Bluefin tuna dive to 1000 meters.

· Winter: stayed in area of release off North Carolina

· Spring: under took trans- Atlantic migrations from North Carolina to spawning grounds in Gulf of Mexico and Eastern Mediterranean.

· During transoceanic migrations, individuals are subject to ambient temperatures ranging from 2.8°C to 30.6°C.

· BUT tuna maintained constant internal temperature around 25°C using regional endothermy.

· Elevated body temperatures of bluefin tuna increase their capacity for rapid migrations by increasing the power output of their muscle.

Question 3

Migratory Movements, Depth Preferences, and Thermal Biology of Atlantic Bluefin Tuna

Block et al., 2001.

Critical analysis

Answer 3

Critical Analysis:

• · This study was significant as it combined three sets of data:
  
  • migratory movements of tuna
  • ambient temperature
  • internal temperature of the individual.
• As three bits of data were collected from each individual, it allowed clear patterns and correlations to be established.
• Drawbacks of the investigation include the limited number of organisms successfully recaptured.
• Whilst 279 individuals were implanted with archival tags, only 49 tags were retrieved, just 18%.
• Other data was utilised from previous study to augment results, BUT in the future an increased sampling effort could increase result validity.