Fish

Characteristics of Fish Skeleton made of ________ _______________ bladder for buoyancy Mucus to reduce friction, ______________________________ ____________ (operculum) to protect gills and pump water through them (oxygen)

Small, thin scales for rapid swimming ___________ fins (not stiff as in sharks) Lateral line and other senses, but no ______________ ______________ (cold blooded)

Major Groups of North Atlantic Fish Demersal Fish:____________________ ________________________________ –________: cod, haddock, pollock, cusk, hake –_________: flounder (sole), halibut, plaice, turbot

Pelagic Fish: __________________ –___________: herring, sardines, shad, smelt, menhaden, gaspereau, capelin –_________ –Mackerel, Salmon, Eel

Deep Sea Fish Deep sea fish tend to live below ____ m They have anatomical adaptations to live at these depths such as: ________________________________________ Many are smaller than ___ inches

Grenadier: mGulper: m Hatchet: m Swallower: m

Lantern: mScaly dragon: m Viper: m Tripod: m

Angler Fish There are several different species They usually live between _________m Some have a ____________ They use a ______ to attract prey There is one species where the female is ___x the size of the male; he lives as a ___________ on her body

Fisheries and Fishing Techniques

Fisheries Facts Unlike other natural resources such as oil and gas, fish are a ______________ People in coastal regions have been using fish as a major food source for thousands of years In 1997, the global fishery took ________ million tons of fish, crustaceans and molluscs

Fishing employs ~___ million people worldwide, but is the most dangerous job in the US (155 deaths: fishers) Of the thousands of species of marine organisms in the ocean, only about _____ species are regularly caught as part of a commercial fishery

The largest commercial harvest is _________ and relatives (sardines, anchovies) which comprise 20% of the worldwide catch each year The top five fish harvesters in order from greatest to least are:

Commercial Fisheries Major types of commercial fisheries include: –______________: cod, haddock, hake –______________: sardine, anchovy, herring, mackerel, tuna –______________: crab, lobster, shrimp, krill –______________: oyster, mussel, clam, squid, scallop

Technology Improves Catches ____% of fishers are cast commercial fleets who find fish using: → Huge factory ships follow along to can and freeze the fish as soon as they are caught

Fishing Techniques: Trawling (dragging) The most common method of fishing A _______________ net is towed behind the fishing vessel Can be towed on the _______________ to catch groundfish or at _____________ to catch pelagic fish Bottom dragging is very ____________ to the benthic ecosystems

Trawling

Purse Seine A net _________________________ ______________________________ ______________________________ ______________________________

Purse Seine

Scallop Dragger Scallops are caught by __________ – a metal frame with a net attached rakes the sandy bottom This method is also destructive to the benthic environment

Scallop Dragger

Gillnetting/Driftnetting A passive fishing method (_______ km long) A gillnet is a wall of netting set in a straight line equipped with ________ at the bottom and _________ at the top Fish swim through the net and are caught when their gills become entangled in the net If the nets are allowed to drift freely, the method is called ____________ Must be checked ____________

Gill Net

Long-lining Long lines of ____________ hooks km long There are ____________ of baited hooks placed in the open ocean, or along the bottom

Long-lining

Lobster Pots Lobsters are caught in baited traps with funned shaped openings allowing only ______ direction of travel – in They can be single traps, or in groups on a line

Lobster Trap

Weirs A passive fishing method A weir is an enclosure made of nets and poles _____________ attached to the bottom Leader fences direct fish into the circular weir where they will ______________ until they are removed by the fisher ___________ and ____________ are often caught in weirs

Weirs

Jigging Squid and cod are often caught by jigging – a line of hooks are continually jerked to lure the fish to bite

Fishery Problems: By-catch Animals that are _______________ killed when desirable organisms are fished In many cases, _____________________ ___________________________ Thousands of _____________ were caught in tuna nets until regulations changed the net design and ship maneuvers

Every method of fishing has this problem About ______________________ of unwanted fish may be discarded annually either because regulations prevent capture of these fish or because it is not ___________________ to process them

Ghost Fishing Nets will keep fishing after they have been lost due to _________________________ Fish and other organisms will rot in the nets because there is no-one to collect them _________________________________ cause the most problems

Habitat Destruction Destroying the ocean floor in the process of dragging nets The bottom becomes ‘_________’ and it takes a long time to recover – if it does ______________ and _________________ cause the most damage

Declining Fish Populations Fish stocks worldwide have been declining; many have collapsed due to _________________ Other reasons for declining numbers are: __________________________________ __________________________________ __________________________________ __________________________________

Fisheries Management Scientists study fish stocks to determine estimates of the _________________ and the reproductive biology of the species This information allows scientists to estimate the _______________________ and determine the __________________________________ __________________________________

Scientists can determine the minimum size of fish to be caught to ensure _____________ are not being harvested They can also determine times of the year when no fishing should be allowed to __________________________________ Scientists make ____________________ to the fisheries managers

Fisheries managers set the ___________ ___________________________ (total tonnage of fish that a fleet can catch) They also set ________ (total tonnage of fish that a fisher can catch)

Fisheries Mismanagement Poor science leads to poor estimates Managers disregard scientists recommendations Fishers do not obey quotas Other factors (not taken into consideration) may deplete the population: foreign fishers, weather, pollution etc…