Lecture 28- Temperate marine habitats

Question 1

What are the characteristics of temperate marine habitats?

Answer 1

• Low diversity • High endemism (>80% of southern marine fauna are endemic!) • 85% of fish • 90% of echinoderms • 95% of molluscs • Long history of isolation • >65 million yrs

Question 2

What are some examples of temperate marine habitats?

Answer 2

• Seagrass meadows • Kelp forest • Sub-­‐tidal rocky reefs • Soft sediments: mudflats and sandy beaches • Intertidal rocky shores

Question 3

What is the distribution of marine habitats around Australia?

Answer 3

-

Question 4

What are seagrass meadows like?

Answer 4

-Australia has largest area of temperate seagrass -30 out of 58 worldwide seagrass species occur in Australia -Form in sheltered bays, in shallow, clear water with sandy substrate -very productive habitat (30 cm growth a day) -important nursery grounds (fish and crustaceans) -provide food an shelter -nutrient recycling -help stabilize soft sediment

Question 5

What are kelp forests like?

Answer 5

-found in S. Aus especially Victoria and Tasmania -form in areas with rocky reefs -very productive habitats (need upwelling that is why few in australia) -kelp= brown algae -fronds can grow 50 cm a day -can grow to above 30 m -used as thickener in ice cream and jelly -provide complex habitat, shelter, and food for many species

Question 6

What are temperate rocky reefs like?

Answer 6

-more productive than tropical reefs -in shallow water, dominated by algae (ie kelp) -in deep water, dominated by filter feeding epifauna: ascidians, sponges, bryozoans -both provide complex structure and habitat for many species -many endemic species

Question 7

What are the 3 examples of sharks and rays?

Answer 7

• e.g Spotted wobbegong (ray): mostly hide during the day, very good at camouflaging -fiddler ray= also camouflaged ray(looks like light) -port jackson shark: has few pointy sharp teeth at the front, have bog teeth in the back to crush shells

Question 8

What are the 3 habitats in temperate regions (main)?

Answer 8

-rocky reefs, kelp forest and seagrass

Question 9

What are the characteristics of sharks and rays? (elasmobranch)

Answer 9

-many are endemic to australia -nocturnal carnivores (octopuses, sea urchins, molluscs, crustaceans and fish) -spend days hiding in caves or overhangs or lying half buried on sandy bottom -all good at camoouflage .spotted webbegong: has fleshy projections hanging from nostrils used in taste and feeling for prey -porzt jackson shark: specialized teeth (not serratated, front= small/ pointed and rear: broad , flat

Question 10

What are he shark reproduction like?

Answer 10

-internal reproduction, fertilisation -many have to reach like 5 years to mature, long time to mature -low fecundity -diverse strategy -have slow reproduction -are oviporous: leathery egg cases, cork screw shape, so they drill into the sand until hatching -some egg cases are more flat and are on stones -many sharks are viviparous, have a pseudoplacenta= blood exchange between mother and young -some also ovoviparous= egge in the mother and birth,difference is that the nutrition is from the egg yolk not the mother

Question 11

What are the characteristics of pipefish, seahorses and seadragons (Sygnathidae)?

Answer 11

-over 200 species (above 30 in temperate Australia) -some of the greatest diversity in body size and shape -micro carnivores -brooders (attached/embedded eggs, open/sealed pouch) -male parental care -eg. Leafy seadragons, weedy seadragon, ghost pipefish

Question 12

What are the characteristics of the Old wife fish? (Enoplosiadae)

Answer 12

-monotypic family, endemic to Southern Australia (one genus) -name refers to grating sound made when stressed -poisonous first dorsal spine -black and white

Question 13

What are the characteristic of Boxfishes and Cowfishes? (Ostraciidae)

Answer 13

-have hard bony carapace -name refers to boxy or cow like appearance -move like small submarine -fine motor control with pectoral fins -found in temperate and tropical waters

Question 14

What are the characteristics of Morowongs (Cheliodactyladae)?

Answer 14

-center of diversity in southern australia -restricted to temperate waters -benthic micro carnivores -have large rubbery lips -very long larval stage (several moths) -peculiar juvenile stage (have papery stage, settle on reef when big, several cm)

Question 15

What are the characteristics of Weedfish (Clinadae)?

Answer 15

-center of diversity in southern australia -experts at camouflage (look like weed, kelp) -not a lot known about them

Question 16

What are the characteristics of the Handfishes (Brachionichthyidae)?

Answer 16

-4 species -do not have a larval stage, do not disperse very far -juveniles are like miniature adults, unusual -benthic egg layers -lack planktonic larvae stage -species in decline (loss of spawning habitat?) -found almost exclusively in Tasmania in shallow water -live in small breeding colonies -walk using modified pectoral fins

Question 17

What are the characteristics of Giant Australian Cuttlefish? Sepia apama (invertebrate)

Answer 17

-endemic to southern Australia -largest cuttlefish in the world (50 cm long, with tentacles above a metre) -feed on small fish, crabs, and crustaceans -form hige mating aggregations in Spencer Gulf, SA, the small males who can’t mate as easily, they take on the colour of a female to sneak in (becuase only large males would normally mate) -can change colour instantly as well as shape and texture of skin

Question 18

What are the characteristics of Eleven arm seastar (C. muricata)?

Answer 18

• largest seastar in southeastern Australia -voracious predator: eats molluscs, crabs and worms -can have 7-14 arms -can reproduce by dropping a leg

Question 19

What are the characteristic of rock lobster? (predatory invertebrate)

Answer 19

-important commercial and recreational fishery -nocturnal predators: eat mussels, sea urchins, crabs, abalone -live in crevices and overhangs -very long larval stage

Question 20

What are the characteristic of sea anemone?

Answer 20

-can eat a sea urchin -sit and wait predators -use stinging tentacles to capture prey

Question 21

What are the characteristic of ELephant snail? (benthic hebrivore)

Answer 21

-scutus antipodes -very large (up to 12cm) -so called because it swings its tentacles around -related to limpets -nocturnal (hides during the day)

Question 22

What are the characteristic of Blacklip abalone? (benthic herbivore)

Answer 22

.haliotis rubra -very important commercial fishery (and recreational) -endemic to Southern Australia -feed on drifting algae -don’t move very much

Question 23

What are the characteristic of Long spine sea urchin? (benthic herbivore)

Answer 23

-C. rodgersii -native to NSW -when populations boom can lead to urchin barrens -range extension to Tas where it is decimating kelp (due to warming of the sea)

Question 24

What are some sessile animals on rocks?

Answer 24

-all filter feeders -colonial ascidians -bryozoans -sponges

Question 25

What are the soft sediments or Mudflats like?

Answer 25

-areas where low tide exposes soft mud -very fine sediment, usually anaerobic below surface -dominated by filter feeding and deposit feeding invertebrates -important feeding grounds for birds and fish

Question 26

What is the soft sediment infauna and epifauna?

Answer 26

-the pippy: burrow in sand, sucks in water from the surface and filter it -soldier crab: deposit feeder, and moon snail (predator) -polychate worm

Question 27

What are the benthic predators?

Answer 27

-eg. ELephant fish -feed on molluscs and worms in sediment -use their noses to detect electrical signals from moving animals in the mud

Question 28

What are the temperate rocky shore like?

Answer 28

• dominant forces: wave action and tides -sloping shores characterised by distinct zones
• top of shore exposed to hot and dry conditions and waves
• bottom is only in exposed for short periods
• molluscs often dominate especially in upper zones
• predators, larger animals lower on the shore

Question 29

What is the zonation like in the temperate rocky shores?

Answer 29

-characteristic zonation= gradient of dryness -splash zone (lichens, Littoria grazers) -barnacle zone (Barnacles) -Limper and mussel zone (also Galeolaria and Hormosira) -Sublitorral fringe (large algae, octopus, sea urchins and seastars)

Question 30

What is the intertidal platform of the temperate rocky shores like?

Answer 30

-no zonation becuase it is flat -often dominated by Hormosira banksii (Neptune’s necklace) -animals protected from desiccation by algae -lots of tide pools provide diverse habitats too

Question 31

What are the threats to temperate marine habitats?

Answer 31

-human activities (boat anchors, trampling, removal of plants and animals) -overfishing -introduced species -inputs from terrestrial runoff = sittation, toxicants, sewage, oil spills -climate change (especially sea surface temperature, sea level rise and ocean acidification)

Question 32

Summary?

Answer 32

-habitat types: seagrass bed, kelp forest, subtidal rocky reefs, soft sediments, intertidal rocky shores -very high endemism -lower diversity than tropics -many threats (similar to tropics)