Podcast question how have fish in the ocean changed when compared to the fish that would have been found several decades ago o Fewer smaller fish Podcast Fishing down food web means o We remove the top of the food web first then move on down the web and remove the next level Podcast two main impacts of fishing on ocean o Removal of fish habitat destruction with fishing gear Podcast why did the cod fishery in New England collapse o We overfished it Feeding and Trophic Interactions Feeding mechanisms filter feeding active vs passive o Passive don t actively move through water water passes through them to filter o Active moves to force water across gills o Passive effects of flow on filter feeders Fed oysters in flow through tanks at different flow speeds and 2 different food concentrations Quantified growth of oysters when there was more flow o Blue whale lunge feeding rorqual whales pleats along neck under chin active process facilitated by muscular contraction Allometric scaling mechanics of lunge feeding sets the upper size limits of rorquals larger whale reduced size of tail more energy to move come up to surface for air more often larger mouth more energy to feed limits max size whales can reach Quiz What will happen to rorquals if the population of krill substantially declines Rorquals will not grow as large due to energetic constraints food is less abundant can t make larger lunges Deposit feeding o Very important in soft sediments o Up to 90 of soft sediment organisms o Detritus dead and decaying plant material o Where do deposit feeders get their energy Dead matter Microbes that decompose dead matter Specific energy sources may differ for each deposit feeder depending on location Lugworms o Why are they important Play an important role in mudflat ecosystem Convert detritus food into macro organism biomass that is available to higher trophic levels basis of food web Resuspend particles which increases oxygen and nutrient levels in sediments Aerate the soil through bioturbation or their disturbance of the sediment as they burrow Stabilize the sediment by secreting mucilage a material consisting of carbs o Quiz more deposit feeders at an estuary fed by a slow river or open coast sandy shore with high wave action Estuary smaller sand particles larger SA deposit feeders eat food that is mostly on the surface so you want a larger SA more food Herbivory o Microherbivores snails macroherbivores manatees o Feeding structure Aristotle s lantern most complicated jaw structure Predation o Oyster catchers sharks lionfish invasive predator Evertible stomach o Sea stars stick stomach outside of mouth use tube feet etc Dinoflagellates break down fish tissue and possibly release toxin Cannibalism tiger sharks eating their embryonic siblings in the womb Symbiosis coral symbiosis with zoozanthellae o Coral bleaching is loss of symbiont Parasitism Orthioine griffenis Behavior and foraging o Bubble net feeding humpback whales o Dolphins use complex behavior to forage herd lantern fish into a tight group dolphins encircle them facing inwards do the wave sounds and wave disorient lantern fish 2 dolphins opposite each other come in and feed for 15 seconds happens with every dolphins goes through circle twice so each dolphin feeds 2 times o Dolphins strand feeding only in SC Conditions change if adapted to specific conditions how do you respond when conditions change ex polar bears and sea ice Quiz evolutionary trap when conditions change Discuss another example of an evolutionary trap manatees coral with zoozanthellae Case study Florida stone crab Food webs location of the ecosystem Aleutian Islands Alaska o Sea otter population finally increased and then killer whales began eating them both have been present for a long time why do whales eat them now urchin barrens o Completely changes ecosystem Overfishing and loss of large predators around the globe More quiz questions