Unit 4 Topic 2 Managing fisheries Flashcards
Types of fishing (3)
Commercial Fishing
-The activity of catching fish and other seafood for commercial profit mostly from wild fisheries (Demersal trawl, prawn trawl)
Recreational fishing
-Sportfishing for pleasure and competition (rod, reel, and hooks)
Artisinal fishing
-Various small scale, low technology, low capita fishing practices undertaken by individual fishing households (fishing traps and beach seine)
Importance of wild-caught fisheries
A major source of protein to oceanic countries. Is useful for small countries without the land for traditional farming
How fishing data is reported
- Fishermen send catch data to government authorities
- Scientist is placed on a vessel to conduct a personal investigation (Age, size, length, and maturity level
- Scientists conduct personal research on a vessel
- Stock assessment is created
- Data is published by FAO
Fish population distribution is influenced by
The amount of food in an area is determined by the amount of phytoplankton in the area. Phytoplankton are located in areas with sufficient nutrients such as
- Dissolved Nitrogen
- Dissolved phosphate
- Dissolved iron
- Silica
Rugosity is
An index that measures habitat complexity and is expressed as a number from 0-3
-The higher the number the higher the fish diversity
Fish diversity is measured through
- Species richness
- Species diversity
- Simpsons diversity index
- functional diversity
Bioaccumulation
- The accumulation of substances such as pesticides, heavy metals, or other organic chemicals
- Bioaccumulation occurs when a substance is absorbed faster than it is excreted
- Bioaccumulation occurs when with the repeated consumption of contaminated lower-order consumers overtime
Bioaccumulation and bioindicators
Some organisms accumulate the chemical in their body to a concentration that is several orders of magnitude higher than the surrounding water and can represent the level of pollution (muscles and mudskippers)
Input and control outputs
Input
-Limitations on the amount of fishing effort or restrictions on aspects of a vessel (vessel, gear size and time of fishing)
Output
-Limitations of the weight of the catch (quota) or allowable size, sex or reproductive condition
Fishing technology
- Sonar
- Navigation gear
- More effective boats
Tagging limitations
- May affect growth and survival
- Impact behavior and swimming/hiding performance
- Fouling of tags
- Tag loss
- Tag entanglement with fishing supplies
Lincoln Index formula
N= M x n/m N = Stock size M = number tagged n = second catch m = recaptures
CPUE
Catch per unit effort
Methods to test fisheries data
- E-monitoring
- Vessel monitoring (VMS)
Lincoln index assumptions
The method assumes that tagging does not affect survival, nor the probability of recapture. It also assumes that no migration occurs
Methods scientists use to measure the amount of fish present
- Lincoln Diversity index
- Underwater visual census (Baited remote camera)
- Acoustic methods (fishfinder, sonar)
- Egg production method (density of eggs in water)
- Depletion method (CPUE)
- Portside sampling (fish frames, otoliths)
- Marketplace data
Factors that determine the reliability of fisheries population data (fish behavior)
- Schooling
- Spawning
- Diel migration