Oceanic Nekton. Fishes. Agnatha Hagfish. Classification of Fish. Lampreys

Transcription

1 Oceanic Nekton Fishes Classification of Fish Agnatha Hagfish Notochord; slime!; cartilaginous skeleton; poor eyes; slime (I know, but its worth mentioning twice ) Lampreys Notochord; Dorsal Fin; well developed eyes 1

2 Class Chondrichthyes Cartilaginous Fish Jaws; scales; spiral valve in intestine; pared gills Subclass Elasmobrachii- Sharks, skates, rays Subclass Holocephali- Chimaeras Chondrichthyes External Anatomy Chondrichthyes Internal Anatomy Sensory Structures Lateral line Ampulla of Lorenzini 2

3 Plate mouths Subclass Holocephali Class Osteichthyes Subclass Actinopterygii Ray-finned fishes Bony skeleton; scales; paired fins; supported by rays; Gills covered by operculum; Swim bladder Class Actinopterygii Subclass Crossopterygii- Lobe-finned Fishes Coelacanth 1938 off Africa 1998 found in Indonesia One of the Sarcopterygii groups shares a common ancestor with the Tetrapods Diversity of Body Shapes Locomotion Similar habitats/ niches can show very similar body shapes between groups Swimming in Nekton Anguilliform Eel, lampreys, etc. Carangiform Jacks, snappers, tuna Ostraciform Boxfish, cowfish, 3

4 Locomotion Underwater Flying/Rowing Pectoral fins Dorsal and Anal Arms/legs Others Myomeres 4

5 Swim Bladders Buoyancy Control Physostomous-with duct to gut Ancestral, Mostly shallow water forms; gulp air Physoclistous-no duct Rete mirabile-capillary bed Counter-current O 2 and others Buoyancy Control Buoyant Organs Swimming lift Swim Bladder Respiration Counter-current gas exchange Air /Water challenges 5

6 Ion Balance How smart are Fishes? Other Nekton Marine Reptiles Class Reptilia Order Chelonia- Turtles Shell (carapace), non-retractable head 9 species, all threatened or endangered Tied to land for reproduction Order Squamata- Snakes and Iguana 55 species of sea snakes, many never come on land, highly poisonous, small mouths. Galapagos Marin Iguana, feeds on seaweeds Order Crocodillia- Crocodiles Tropics, mangroves, estuaries, and open sea Up to 33 ft long, very aggressive 6

7 Class Aves- Marine Birds 64 day male incubation in heart of winter timed to? Tubenoses Webbed footed birds Albatross Shearwater Pelican Cormorant Gulls and others Phalaropes Congregate at fronts and Langmuir cells Puffin- N. Hem penguin Tern Now that is a Migration! 7

8 Class Mammalia Order Pinnipedia (Carnivora?) Seals, Sea lion, Walrus Blubber for insulation California Sea Lion Zalophus californianus Harbor Seal Phoca vitulina Elephant Seals Mirouga angustirostris California Sea Otter Order Carvivora, no blubber Hunted to near extinction by late 1700s Cal. Sea Otter extinct 1831; rediscovered ,505 California sea otters in 2003 Enhydra lutris Record divers- 1,500 m, over an hour Otter Repopulation Otter-Free Zone Federal no-otter zone that encompasses all of southern California - the most critical portion of the sea otter's original range (Pt. Conception to the Mexican Border, including the Channel Islands). Since the late 80s, sea otters have not been allowed, by federal regulation, to exist in the zone. The no-otter zone was created as part of a deal to re-introduce sea otters at the remote San Nicolas Island (and to appease Urchin fishermen) Through the early 90s, otters found in the zone were pursued, trapped, and relocated. Beginning in 1998, sea otters have returned to the "zone" 90-day public comment period; Nov 3 rd meeting in MB 8

9 Polar Bears Ursus maritiums (Artic) Manatees and Dugongs Order Sirenia 1000 West Indian Manatees alive in Florida Only 4 species left, all endangered Whales- Order Cetacea Toothed Whales- Odontocete Dolphins, Porpoises, Orcas, Sperm Whale Baleen Whales- Mysticeti Blue, Humpback, Grey Blue Whale (Balaenoptera musculus) Humpback Whale (Megeptera novaeangliae) Gray Whale (Eschrichtius robustus) Bottlenose Dolphin (Tursiops truncatus) How many whales were there? 9

10 Whale Harvest- shifting species International Whaling Commission (IWC) Est attempted to regulate whaling worldwide Whaling still not enforced, Blues still hunted in the 70s Once stocks become tragically low, and not economically viable then are protected Moratorium on all whaling in 1985 Japan, Iceland and Norway still hunt for scientific purposes 1000s still taken each year. What do they Eat? Baleen Whales 10

11 Euphausiid Shrimp Humpback Feeding Krill Bubble Nets oceanfootage com/stockfootage/bubble Orcinus orca- the whale killer Wolves of the Sea Echolocation Transient vs. resident populations What is Ambergris? Spermaceti sacs Shifting Prey? Predation Shifts and Ecological Effects Where are the Alaskan Sea Otters going? Who is Next? 11

12 Migrations Birds Mammals Fish Turtles TOPPs Tagging of Pacific Pelagics Tagging Experiments Atlantic Bluefin Tuna Migrations Foraging Behavior Elephant Seals 12

13 White Shark Migration Albatross How to (not) Dispose of a Whale The INFAMOUS video 13