How well do you know marine life? - Part 2

[DaLilFishie]

Same as the last one, post your answers in the comments (no peeking!) and I will post the answers after there have been a few participants.

1. Which group of fish is not only the most populous and has the highest biomass of all fishes, but of all vertebrates?

2. How many legs does an octopus have? (hint: it's not eight)

3. What group is the genus Epinephelus? Name 3 species

4. Ciguatoxin is a toxin found in the flesh of some reef fishes, and is dangerous to humans. The fish do not produce the toxin themselves. Where does it come from?

5. True or false? Female giant isopods carry their young for a period after hatching in a pouch on their stomach, similar to a kangaroo.

6. Which of the following is not a true crab?
a. Red-Streaked Box Crab
b. Hoff Crab
c. Red-Spotted Guard Crab
d. Japanese Spider Crab

7. What species of fish is this?


8. What is the deepest-living fish species?

9. Cyprinodon desquamator is a pupfish with a highly-specialised diet. What does it eat?

10. How would one distinguish between a sawfish and a sawshark?

 

[Junklekitteb]

1. Stomiiformes.
2. 0 or 1, depending on if you count the mantle which I believe developed from the foot of other molluscs.
3. Groupers, not sure about species but I’ll go with red, blue and green grouper since they all have boring sounding names .
4. I don’t know.
5. True, I think? Not sure.
6. (a.) I think.
7. Alfonsino.
8. Mariana Snailfish
9. The scales of other fish.
10. Not sure, but I think the fins? In sawsharks they have a ‘nornal’ shark arrangement but in sawfishes they are wider and less distinct.

 

[Tetzoo Quizzer]

2. I recall seeing one study which recognised 6 legs and 2 arms.
4. The toxin is bacterial, derived from the fishes diet.
5. True.
6. B
10. Saw sharks have a barbel on the snout which is lacking in sawfish.

 

[DaLilFishie]

Answers

1. Family Myctophidae, the lanternfishes

2. They have 2. The back two limbs are used mostly for locomotion, so are legs. The other six are arms as they are mostly used for manipulating objects. Morphologically, they are the same, only their use is different.

3. Epinephelus is a genus of groupers. There are too many possible answers for three species to list here, but for example, Malabar Grouper (E. malabaricus), Giant Grouper (E. lanceolatus) and Longtooth Grouper (E. bruneus).

4. Ciguatoxin is produced by dinoflagellates. The dinoflagellates are eaten by herbivorous fish and the toxin accumulates in their flesh, and accumulates up the food chain.

5. True

6. Hoff Crab, it is actually a squat lobster.

7. Alfonsino, Beryx decadactylus

8. Abyssobrotula galatheae, at a depth of 8,370 metres. Half points for Mariana Snailfish, which you may have heard of being the deepest fish species, but lives about 300 metres shallower than A. galatheae.

9. The scales of other fish, which it rips off still-living victims.

10. Many correct answers, including:
- location of gills (sawfish have them under the pectoral fins, in sawsharks they are above the gills)
- fin shape (sawfish pectoral fins are wider and less distinct from the body)
- barbels (sawsharks have barbels, sawfish do not)
- size (adult sawfish are much larger than sawsharks, adult sawsharks reach 1.5 metres, whereas sawfish reach 7 metres)
- body shape (sawsharks are more slender than sawsharks)
- rostral teeth (sawfish rostral teeth are more or less the same size, in sawsharks they alternate between large and small teeth along the length of the rostrum)