seabirds, tuna, conservation & fisheries Flashcards
marine invasive species / alien species
organisms that have been introduced into ecosystems where they do not historically or naturally occur
state some physical changes to marine env resulting from climate change
- sea-level rise
- ↑ sea surface temp
- slowing thermohaline circulation
- melting land-ice
- extreme events
- ↑ air temp
- ocean acidification
IUCN red list
inventory of global conservation status and extinction risk of biological species
what makes a bird a seabird?
entirely dependent on marine env for at least part of their lives
why are seabirds important?
important ecosystem engineers
- help regulate plankton
- can exert top-down control on forage species -> regulates pops of prey species -> preventing overgrazing / overfishing of certain organisms
- transfer nitrogen and phosphorous to land
- guano (droppings) rich in nitrogen, phosphorus, etc, -> enhances soil fertility and promotes plant growth
- guano enhances productivity on coral reefs
sentinel marine species
- one that can provide early warning of existing / emerging health hazards from ocean env
- seabirds are one of these
why is the UK globally important for seabirds?
- host globally important breeding pops
- ~8 million birds of 25 breeding species
- annual monitoring programme since 1986 (Seabird Monitoring Programme, JNCC)
- irregular censuses of all breeding pops
-> ~68% of northern gannets
-> ~90% of Manx shearwaters
-> ~60% of great skuas
status of seabirds in the UK?
- uk seabirds have contrasting fortunes -> some get lucky, some don’t
- seabirds ↓ by ~50% from 1990->2010 using **discard data (poo) **
why should we care about marine conservation?
marine ecosystem goods and services are important for human health
- healthy coral reefs are hotspots for biodiversity and can be source of new medicines / healthcare products
- offshore reefs create sand -> protect shoreline from severe storms
- scenic env provide scuba diving, kayaking, sailing
- estuarine seagrasses and mangroves provide nursary habitat for commercially targeted fish and crustaceans
- oceans produce half of O₂ we breathe
- offshore energy (windmills in sea) provides power to support coastal development
- seagrasses / mangroves / saltgrasses act as carbon sinks -> ↓ g.g
drivers of biodiversity loss
- Over-exploitation
- Habitat Degradation
- Pollution
- Invasive Species
- Climate change
why is lack of data a limitation in marine conservation?
need to know…
- know abundance & distribution of species
- understand life histories of species
-> challenging to formulate effective conservation strategies without these - understand socio-economic drivers of human behaviours
-> without data: difficult to understand impacts of human activities on marine env. (Includes effects of overfishing, habitat destruction, pollution, climate change) Lack of data stops identification of critical threats
^all of that is hard to do in the ocean
compare the elasmobranch sp data on the IUCN red list from 2012 and 2023
- ↑ in threatened species
- ↓ in data deficient sp
how to reduce the threats to marine conservation?
- ↓ bycatch
- ↑ farming
- ↓ predation / invasive sp
- ↑ hatcheries / relocation
- education and awareness
List 3 of the advs of using oceans to support human consumption
- renewable resource
- food security
- employment
importance of fisheries
(to economy)
- 59.5 million people in fisheries & aquaculture in 2018 (85% Asia; 9% Africa)
- employment has grown faster than global pop – almost twice the rate
- 4.4% of 1.3 billion economically active people
- 1 in 2 workers in this sector is a woman when including post-harvest operations
landing
fishing terminology
amount of fish (in pounds or as no. of fish) caught by fishermen & delivered at docks
… then sold for profit / kept for personal consumption
catch
fishing terminology
- total no. / pounds of fish captured from an area over some period of time
- catch may take place in area diff from where the fish are landed
discards
fishing terminology
- the fish -often dead or dying- that are returned to sea during commercial fishing operations
- discarded fish do not count towards a fisherman’s quota
bycatch
- unwanted fish & other marine creatures trapped by commercial fishing nets…
- during fishing for a diff sp
commercial / industrial fishing
practice of harvesting marine or freshwater resources for commercial sale
artisanal fishing
- consists of various small-scale, low-tech, low-capital, fishing practices undertaken by individ fishing households
- making short fishing trips, close to shore, mainly for local consumption
mechanisms to improve fisheries
- Time-area closures
- Zoning
- Quotas
- Gear modification
- Marine protected areas
- Aquaculture!?
mariculture
farming of marine organisms for…
- food
- pharmaceuticals
- food additives
- jewelry (e.g., cultured pearls)
- nutraceuticals
- cosmetics
aquaculture
breeding, raising & harvesting…
… fish, shellfish, & aquatic plants
(basically farming in water)
key attributes of aquaculture / mariculture
- desirability / marketability
- uncomplicated reproduction
- hardiness
- high growth rate
- readily met food requirements
- readily met habitat requirements
- monoculture/Polyculture
- minimal ecological impacts (feed/waste/invasives/pollution)
monoculture in mariculture
when only 1 fish sp gets farmed in a single aquaculture env
polyculture
production of 2+ fish sp within a particular aquaculture env
Why do fish farmers use polyculture instead of monoculture?
- ↑ productivity
- in a polyculture system -> diff sp can occupy diff niches within same env …
- … utilising resources more efficiently and ↑ overall yield
Atlantic bluefin tuna
Thunnus Thynnus
- large, commercially exploited apex predators
-
endothermic (broad env niche)
-> able to maintain a constant body temp regardless of ambient temp - stock assessment & TACs = effective conservation
- extensive knowledge of spatial ecology throughout range & life-cycle required
- complex spatial dynamics:
-> Fishing pressure
-> Climate
-> Recruitment
