Grouping Behaviour impacts on the parasitic pressure and squamation of sharks

Question 1

Who wrote this paper?

Answer 1

Humberto G. Ferron and Jose F. Palacios-Abella

Question 2

When was this paper published?

Answer 2

April 2022

Question 3

What are possible advantages to grouping behaviour for aquatic vertebrates?

Answer 3

-Dilution Risk
-Co-operative hunting
-Swimming energetics and migration

Question 4

What disadvantages are there to group living?

Answer 4

-Decreased foraging efficiency
-Increased risk of parasitism

Question 5

What are monoxenic parasites?

Answer 5

Are parasites with direct life cycles and only need one host to complete their lifecycle

Question 6

What is squamation?

Answer 6

Is complex anatomical structure that is made up of minute dermal denticles (placoid scales) that are on the skin of sharks
-Arrangement of their scales

Question 7

What is the purpose of gracile carinated scales?

Answer 7

-Present in active pelagic species
-Involved in reduction of drag

Question 8

What are rounded and robust scales used for?

Answer 8

-Protection against abrasion and stabilisation of the leading edges of the fins

Question 9

What is the purpose of star shaped scales?

Answer 9

-Concave and needle like
-Accommodate photophores for bioluminescent species

Question 10

What is the purpose of hook and thorn like scales?

Answer 10

-Help prevent the settlement of ectoparasites and epibionts

Question 11

What was the aim of this study?

Answer 11

-To understand the trade-offs and costs associated with social behaviours and the drivers of parasitic interactions with sharks
-To determine if squamation changes with grouping behaviour and increased risk of parasites

Question 12

How many sharks were studied on parasite richness?

Answer 12

213 shark species

Question 13

What was found about parasite richness between species?

Answer 13

It varied depending on the species
-Parasite richness increased with frequency of grouping behaviour

Question 14

What is the squamation like for schooling species of low to moderate speed?

Answer 14

-Have larger crown scale insertion angle than strong-swimming pelagic species, demersal species on rocky substrates, and slow species in open water

Question 15

What did this study find out about squamation?

Answer 15

That species that show occasional grouping behaviour have greater scale coverage compared to species that show frequent grouping behaviour.

Question 16

How does grouping behaviour affect parasite richness?

Answer 16

-Grouping behaviour does have an effect on the richness of parasites
-Sharks that show grouping behaviour have greater parasite richness than those that display a solitary lifestyle

Question 17

What is the squamation like for species that aggregate together?

Answer 17

-They have large crown insertion angles and less scale coverage
-May be a defense against parasite attachment

Question 18

What helps prove that squamation affects parasite attachment?

Answer 18

-Species that have crowns that point upwards mainly have parasites on mouth cavity and gills, were these scales are not present

Question 19

How does large crown insertion angles and low scale coverage reduce parasites?

Answer 19

-Reduces the effective surface area for the adhesion and migration of ectoparasites and provide an inadequate microhabitat for the larvae