Larval Nutrition

Question 1

What are the three patterns present in larval food sources

Answer 1

Some antarctic larval species selectivity ingest bacteria
Food particle size increases with larval size
Soft body larvae are osmotrophic

Question 2

What is lecithotrophy

Answer 2

An adaptation commin in deep sea and polar species

Question 3

Why is lechitrophy found in deep sea and polar species

Answer 3

Due to food being limited for long periods

Question 4

How does planktrophic species respond in areas where food production is not limited for long periods

Answer 4

They respond by restricting larval season to time of high food production

Question 5

What trend do we see in larvae of polar species

Answer 5

One peak of phytoplankton restricted to summer months

Question 6

What trend do we see in larvae in temperate regions

Answer 6

Spring peak with a moderate abundance in summer and autumn

Question 7

What trend do we see in larvae in tropical regions

Answer 7

No peaks because food available all year round

Question 8

What do we see in cancer pagurus availability

Answer 8

Northen north sea larval season takes place in summer and is restricted to a short period
South larval season
Wider (more food)
And starts earlier (Greater temps)

Question 9

What do we see in decapod crustaceans in the Irish Sea

Answer 9

Temperate sea, larval development occurs mainly in spring and summer
Under optimal conditions for food availability.

Question 10

What is a temporal match mismatch

Answer 10

When food is not available at the same time of the larval peak due to it beinf shifted

Question 11

What did cushing propose

Answer 11

Year to Year availability in fish recruitment could be caused by yearly match variation in larvae and food

Question 12

What did cush’s study of larval food mismatches find

Answer 12

Did not find any evidence of predators or physical conditions affecting recruitment of larval species

But variations in food were important

Question 13

What can the shifts of mismatches be driven by

Answer 13

Temperature.
Increasing Temperature causes earlier larval release

Question 14

Is food limitation important in larvae

Answer 14

In crustaceans it is
It is not in small and soft bodied larvae of molluscs and enchinoderms

Question 15

How was the role in food limitation tested in starfish larvae

Answer 15

Larvae under natural food concentration compared to that of larvae kept in medium enriched with phytoplankton

Question 16

What were the results of the study on food limitation on starfish larvae

Answer 16

Over more than 2 weeks survival rates unaffected by enrichment no evidence of food limited survival

Question 17

What does low food availability limit

Answer 17

Growth but not survival due to capacity to take up dissolved organic substances such as amino acids

Question 18

What is Nutritional flexibility

Answer 18

Larvae utilise high diversity of prey as food

Question 19

What are the two larvae responses to food patches

Answer 19

Staying in patches for long time
Accessing the patches for a limited time

Question 20

What is the stable ocean hypothesis

Answer 20

Survival depends on the stability of patches

Question 21

How do crustacean larvae respond to patches

Answer 21

They tolerate limited access to prey
Expected in habitat characterised by food plankton patchiness and from diel vertical migration

Question 22

What does stable ocean hypothesis state

Answer 22

Calm conditions lead to formation of thermoclines of fronts in the sea
Under conditions wind-storms water coloumn is mixed now food is diluted