Sasa: First Part Flashcards
What are the general categories of fishing gear according to FAO classification?
Fishing gear categories include
- towed gears: otter trawl, beam trawl, midwater pelagic trawl, rapido trawl
- seine: danish seine, beach seine, purse seine
- dredges: hydraulic
- static gears: gillnets, trammel nets, driftnets
- longlines: pelagig or bottom
- pots and traps
What is an Otter Trawl and what are its environmental impacts?
An Otter Trawl is a towed fishing gear used worldwide, typically at the sea bottom, impacting the sediment and benthic communities. It can be used in shallow to deep waters, and its impacts include habitat disruption and species mortality.
What is a Beam Trawl, and where is it commonly used?
A Beam Trawl is a type of trawl fishing gear used primarily in the North Sea and North Atlantic. It involves an iron beam with sledges and a net, having a high impact on sea bottoms and benthic communities.
Describe the Midwater Pelagic Trawl and its environmental impact.
The Midwater Pelagic Trawl operates in the pelagic zone, generally with less seabed impact than bottom trawls. However, in some regions, it is towed by two vessels and can target species like sardines and anchovies.
What is the Rapido Trawl and its impact on marine environments?
The Rapido Trawl, used in the Adriatic, is a fast-moving trawl with iron teeth that penetrate the seabed, impacting habitats like flatfish and scallops. Its strong interaction with the seafloor can lead to significant environmental degradation.
What are Danish Seine and Beach Seine gears, and their environmental impacts?
Danish Seine has limited impact on sea benthos and involves encircling schools of fish. Beach Seine involves a vessel and fishermen from shore, capturing fish but potentially damaging seagrass beds and habitats.
What is a Purse Seine and its common usage?
A Purse Seine is a large-scale fishing net used to capture species like tuna. It is deployed in a circling trajectory to surround shoals, with the bottom closed off to trap the fish.
What are Hydraulic Dredges used for, and what is their impact?
Hydraulic Dredges, used to catch bivalves, involve high-pressure water to disturb sediments, causing extensive damage to sea benthos and altering the seabed structure.
What are Gillnets and Trammel Nets, and their environmental impacts?
Gillnets are panels of nets that can be floating or demersal, with varying mesh sizes depending on target species. Trammel Nets have three layers, catching fish through entanglement. Both can lead to bycatch and habitat disturbance.
What are Longlines, and what issues do they present?
Longlines are static fishing gears with hooks and baits used to catch species like tuna and swordfish. They pose risks of bycatch, including turtles and seabirds.
What are Pots and Traps, and what species do they target?
Pots and traps are used to catch species like crabs, lobsters, and octopus. Their usage is often regulated to prevent overfishing and habitat damage.
What is discard in the context of fishing, and what are the reasons for discarding e.g. fish?
Discard refers to the portion of the catch that is thrown back into the sea due to reasons like
- undersize,
- low commercial value,
- or lack of space on the vessel.
Discards can result in significant mortality of non-target species.
What are the main causes of discard in fishing?
Main causes include
- fish in poor condition,
- prohibited species,
- inadequate size,
- low commercial value.
What are the discard rates for bottom trawl and beam trawl fishing gears in the Mediterranean Sea?
Discard rates for bottom trawl and beam trawl range between 15% to 39%, with some coastal areas having rates even above 40%.
What are the physiological stress responses in fish due to fishing?
Stress responses include
- behavioral attempts to escape,
- increased CHH hormone mobilization of glucose
over time, potential physiological decline such as
- decreased pH,
- increased ammonia, and
- loss of reflexes.
What is the impact of chronic bottom trawling on benthic communities?
Chronic bottom trawling leads to
- reduced biomass,
- altered community structures,
- favoring small and young species, and
- a shift towards r-strategic communities.
What are the effects of bycatch on marine megafauna like seabirds, marine mammals, and sea turtles?
Bycatch can lead to significant population declines in these groups, with global estimates suggesting around 20 million individuals are discarded annually.
(bycatch can include discard, discard thrown back in sea)
How does seasonal and geographic variation affect bycatch rates in the Mediterranean?
Example:
In the Mediterranean, bottom trawlers operating in coastal regions might have higher bycatch rates of benthic species like crabs, rays, and juvenile fish. In contrast, longliners operating in open waters may inadvertently catch more sea turtles and seabirds. During the summer months, when sea turtles are more active and closer to the surface for breeding, bycatch rates by longliners could be higher in areas where these turtles are present.
What technological approaches are used to reduce bycatch mortality?
Approaches include
- Medina Panels for dolphins,
- Turtle Excluder Devices (TEDs),
- circular hooks for reducing turtle bycatch,
- acoustic devices to deter marine mammals
What are some challenges in reducing bycatch through technological modifications?
Challenges include potential reductions in target species catches, requiring careful negotiation with the fishing community to ensure adoption without loss of profitability.
What is the IUCN Red List, and why is it important?
The IUCN Red List is a critical indicator of the health of the world’s biodiversity, providing information on species’ conservation status, guiding conservation actions, and informing policy decisions.
What are the major threats identified by the IUCN Red List for species conservation?
- habitat loss,
- overexploitation,
- pollution, and
- climate change, affecting species across various ecosystems.
What is the importance of evidence-based conservation?
Evidence-based conservation ensures that decisions are made based on scientific data,
- reducing bias,
- increasing transparency, and
- improving management effectiveness.
How does systematic review contribute to evidence-based conservation?
Systematic Review
A review, critical appraisal, and analysis of quantitative or qualitative scientific results relating to a specific question, based on a peer-reviewed target search and appraisal protocol. It is used to minimize bias and provide more reliable findings for decision-making.
Systematic Reviews
- collect and synthesize all relevant information through a formal approach,
- providing comprehensive data
- to guide conservation practices.
What are the criteria involved in assessing the conservation status of species?
The process involves quantitative assessments using criteria such as
- range,
- population,
- habitat, and
- future prospects,
ensuring consistency and objectivity in classification.
What is the role of scientific knowledge in biological conservation?
Scientific knowledge provides the foundation for conservation strategies, ensuring that decisions are informed by research and evidence, leading to more effective conservation outcomes.
What are surrounding nets, and how do they operate?
Surrounding nets are used to encircle schools of fish, often operated by a single vessel. They are deployed around the fish and then pulled together to trap the catch, commonly used for pelagic species.
What are seine nets? (What seines are included) and what are their environmental impacts?
Seine nets, including Danish and beach seines, encircle fish and draw them towards the boat.
- Danish seines have limited impact on sea benthos (lightweight gear, touches seabed but doesnt drag)
- The technique of herding fish into a net rather than indiscriminately catching everything in its path means that Danish seines can be more selective, potentially reducing the impact on non-target species and the seabed ecosystems.
- beach seines can cause damage to seagrass beds and capture juveniles.
What is the function of trawl nets, and what variations exist?
Trawl nets are towed fishing gear that can operate at various depths, including bottom trawls like Otter and Beam trawls, and midwater pelagic trawls. These gears can significantly impact the seabed and benthic communities.
How do hydraulic dredges operate, and what species do they target?
Hydraulic dredges use high-pressure water to disturb sediment and catch bivalves. They have a significant impact on benthic habitats, removing top layers of sediment and associated organisms.
What are traps and pots, and how are they used in fisheries?
Traps and pots are static fishing gears used to catch species like crabs, lobsters, and octopus. They are baited and placed on the seabed, often regulated to prevent overfishing and habitat damage.
How do systematic reviews contribute to evidence-based conservation?
A systematic review is a methodical and organized way of collecting, evaluating, and summarizing research studies that have been conducted on a particular topic. Unlike traditional reviews, which might only consider a few studies, systematic reviews follow a strict protocol to include all relevant studies, assess their quality, and synthesize the findings.
Example:
Imagine you’re trying to decide whether creating Marine Protected Areas (MPAs) helps fish populations recover. A systematic review would look at all the studies that have researched this question, compare their results, and then provide a clear answer based on all the evidence. This way, instead of basing your decision on a single study or anecdotal evidence, you have a well-rounded and reliable summary of what’s known.
In summary, systematic reviews are a powerful tool in evidence-based conservation because they ensure that conservation strategies and decisions are informed by the best possible science.
What is the significance of the ecological quality ratio (EQR) in water framework assessments?
The Ecological Quality Ratio (EQR) is a numerical value used to assess the ecological quality of water bodies. It is a key component of the Water Framework Directive (WFD) in the European Union, which aims to achieve good water quality across Europe.
Example:
If a river’s EQR is calculated at 0.75, this means the river is in “Good” ecological status, fairly close to its natural state, but with some human impact. If efforts are made to reduce pollution and restore habitats, the EQR could improve over time, moving closer to 1.
In summary, the EQR is a valuable tool for assessing and managing the ecological health of water bodies, guiding efforts to protect and restore aquatic environments.
What trends have been observed in global fish stocks over the past 30-35 years?
There has been a steep increase in overfished stocks and a decrease in underfished stocks, with the Mediterranean Sea having some of the highest levels of overexploitation.
