WR Adaptations to low food (18, 19)

Question 1

Predicting fish behaviour in response to abyssal food falls.

The study

Answer 1

Predicting fish behaviour in response to abyssal food falls.

(Bailey and Priede, 2002)

Study: Used baited camera systems and trawl data they studied how the abyssal grenadier, Coryphaenoides armatus, forages in comparison to the three models; cross-current, sit and wait and drift foraging.

Different strategies pose different risks. The sit and wait reduces the acoustic and visual signature but creates a detectable odour plume. Cross-current is expensive, noisy and visually obvious but will be able to detect the odour of prey over the greatest area.

Question 2

Predicting fish behaviour in response to abyssal food falls.

(Bailey and Priede, 2002)

Findings

Answer 2

Findings:

A bias of fish swimming from the downstream direction suggests plume following, and that predators may get close and approach from the downstream direction to surprise the prey.

No one model fully describes the observed pattern suggesting that a mix of the three strategies has been employed by the grenadier.

Question 3

Predicting fish behaviour in response to abyssal food falls.

(Bailey and Priede, 2002)

Critical analysis

Answer 3

Possible critical analysis:

This paper has very limited value as they do not have accurate values for the species density or their swimming speeds. Therefore the results are simply a prediction based on arrivals at the bait.

Question 4

Hadal sea cucumber

Study

Answer 4

Functional effects of the hadal sea cucumber Elpidia atakama (Echinodermata: Holothuroidea, Elasipodida) reflect small-scale patterns of resource availability

(Jamieson et al, 2011)

Study: A hadal lander equipped with equipment such as cameras and a CTD was deployed to study the functional effect of the holothuroidea, Elpidia atakama. Holothuroidea represents the dominant megafauna in hadal trenches, but little is known about their behaviour.

Question 5

Functional effects of the hadal sea cucumber Elpidia atakama (Echinodermata: Holothuroidea, Elasipodida) reflect small-scale patterns of resource availability

(Jamieson et al, 2011)

Findings

Answer 5

Findings:

• Different feeding strategies including preferential feeding on nutritionally rich patches are thought to reduce intra and interspecific competition allowing high levels of abundance.
• They have observed ‘run of the mill behaviour’ which is very similar to has been documented at shallower depths.
• The findings provide evidence that E. atakama is a functionally important species which,
  
  • Changes its behaviour in response to localised resource heterogeneity
  • Repackages organic matter
  • Relocation over the sediment constitutes bioturbation, distinct from bioturbation associated with feeding activity, showing that epifaunal species can have a substantial effect on the properties of the sediment profile.
• They estimate that a single individual of E. atakama may process 1 m2 of surficial sediment every 5.1 days.
• Mass abundances are predicted to occur in hadal trenches, in comparison to hadal depths.

Question 6

Functional effects of the hadal sea cucumber Elpidia atakama (Echinodermata: Holothuroidea, Elasipodida) reflect small-scale patterns of resource availability

(Jamieson et al, 2011)

Critical analysis

Answer 6

Possible critical analysis:

Usual deep-sea sampling problems

The whole paper is based on one deploying of the hadal lander. No repeats.

Question 7

Arrow tooth eel study

Answer 7

Scavenging interactions between the arrow tooth eel Synaphobranchus kaupii and the Portuguese dogfish Centroscymnus coelolepis.

(Jamieson et al, 2011)

Study: Observes a scavenging interaction between the arrow tooth eel Synaphobranchus kaupii and the Portuguese dogfish Centroscymnus coelolepis. Has been mentioned in lectures.

Baited cameras were used at 1297 and 2453 m in the eastern Atlantic Ocean continental slope.

Question 8

Scavenging interactions between the arrow tooth eel Synaphobranchus kaupii and the Portuguese dogfish Centroscymnus coelolepis.

(Jamieson et al, 2011)

Findings

Answer 8

Findings:

• Despite consistently rapid arrival times of S. kaupii (<5 min), their feeding bouts (indicated by an acute peak in numbers) did not take place until shortly after C. coelolepis arrived and removed the exterior surface of the bait (skipjack tuna Katsuwonus pelamis carcass).
• At the deeper stations where the population of C. coelolepis declined, S. kaupii was observed to be present but waited for >2 h before feeding, contradicting conventional scavenging assumptions in the presence of a food fall.
• These findings show the importance of Centroscymnus coelolepis in the dispersal of organic matter to the wider deep-sea community.