The effect that seamounts have on fish populations has not gone unnoticed by the commercial fishing industry. Seamounts were first extensively fished in the second half of the 20th century, due to poor management practices and increased fishing pressure seriously depleting stock numbers on the typical fishing ground, the continental shelf. Seamounts have been the site of targeted fishing since that time. Nearly 80 species of fish and shellfish are commercially harvested from seamounts, including spiny lobster (Palinuridae), mackerel (Scombridae and others), red king crab ("Paralithodes camtschaticus"), red snapper ("Lutjanus campechanus"), tuna (Scombridae), Orange roughy ("Hoplostethus atlanticus"), and perch (Percidae).
Fishing
Seamount
Seamount | Fishing
Seamounts were first extensively fished in the second half of the 20th century, due to poor management practices and increased fishing pressure seriously depleting stock numbers on the typical fishing ground, the continental shelf. Seamounts have been the site of targeted fishing since that time. Nearly 80 species of fish and shellfish are commercially harvested from seamounts, including spiny lobster, mackerel, red king crab, etc. Nearly 80 species of fish and shellfish are commercially harvested from seamounts, including spiny lobster, mackerel, red king crab, red snapper, tuna, Orange roughy and perch They were first extensively fished in the second half of the 20th century, due to poor management practices and increased fishing pressure seriously depleting stock numbers on the typical fishing ground, the continental shelf.
what is a chain of underwater mountains called
user
Seamount
assistant
what can you tell about its geographic features?
user
Seamounts can be found in every ocean basin in the world, distributed extremely widely both in space and in age. A seamount is technically defined as an isolated rise in elevation of or more from the surrounding seafloor, and with a limited summit area, of conical form.
assistant
how are these chain of mountains formed?
user
Formed millions of years ago by volcanism, they have since subsided far below sea level. This long chain of islands and seamounts extends thousands of kilometers northwest from the island of Hawaii.
assistant
what can you tell about its structure?
user
Seamounts can form in a wide variety of tectonic settings, resulting in a very diverse structural bank. Seamounts come in a wide variety of structural shapes, from conical to flat-topped to complexly shaped. Some are built very large and very low
assistant
how can you describe its ecological role?
user
Seamounts are exceptionally important to their biome ecologically, but their role in their environment is poorly understood. Because they project out above the surrounding sea floor, they disturb standard water flow, causing eddies and associated hydrological phenomena that ultimately result in water movement in an otherwise still ocean bottom.
assistant
any type of danger associated with it?
user
Yes, seamounts have not been mapped and thus pose a navigational danger.
assistant
what can you tell about its fishing?
user
A seamount is a mountain rising from the ocean seafloor that does not reach the ocean surface. They are defined by oceanographers as independent features that rise at least 1,000 meters above the seafloor. Seamounts became interesting during the 1960s, when it was discovered that they can maintain large stocks of commercially important fishes and invertebrates. From 1968 to about 1990, foreign fleets harvested pelagic armorhead across seamounts in the Hawaiian Ridge. Since 1984, fishing has been prohibited there so the stock can recover. Generally, seamounts are found in the high seas, outside the continental shelves, and outside the jurisdiction of any nation's EEZ.
Fishing industry in the United States | Seamounts
The effect that seamounts have on fish populations has not gone unnoticed by the commercial fishing industry. Seamounts were first extensively fished in the second half of the 20th century, due to poor management practices and increased fishing pressure seriously depleting stock numbers on the typical fishing ground, the continental shelf. Seamounts have been the site of targeted fishing since that time. Nearly 80 species of fish and shellfish are commercially harvested from seamounts, including spiny lobster (Palinuridae), mackerel (Scombridae and others), red king crab ("Paralithodes camtschaticus"), red snapper ("Lutjanus campechanus"), tuna (Scombridae), Orange roughy ("Hoplostethus atlanticus"), and perch (Percidae).
Seamount | Fishing
There are several well-documented cases of fishery exploitation, for example the orange roughy ("Hoplostethus atlanticus") off the coasts of Australia and New Zealand and the pelagic armorhead ("Pseudopentaceros richardsoni") near Japan and Russia. The reason for this is that the fishes that are targeted over seamounts are typically long-lived, slow-growing, and slow-maturing. The problem is confounded by the dangers of trawling, which damages seamount surface communities, and the fact that many seamounts are located in international waters, making proper monitoring difficult. Bottom trawling in particular is extremely devastating to seamount ecology, and is responsible for as much as 95% of ecological damage to seamounts.
Seamount | Conservation
Some seamounts have not been mapped and thus pose a navigational danger. For instance, Muirfield Seamount is named after the ship that hit it in 1973. More recently, the submarine USS "San Francisco" ran into an uncharted seamount in 2005 at a speed of , sustaining serious damage and killing one seaman. One major seamount risk is that often, in the late of stages of their life, extrusions begin to seep in the seamount. This activity leads to inflation, over-extension of the volcano's flanks, and ultimately flank collapse, leading to submarine landslides with the potential to start major tsunamis, which can be among the largest natural disasters in the world.
Seamount | Dangers
Interactions between seamounts and underwater currents, as well as their elevated position in the water, attract plankton, corals, fish, and marine mammals alike. Their aggregational effect has been noted by the commercial fishing industry, and many seamounts support extensive fisheries. There are ongoing concerns on the negative impact of fishing on seamount ecosystems, and well-documented cases of stock decline, for example with the orange roughy ("Hoplostethus atlanticus"). 95% of ecological damage is done by bottom trawling, which scrapes whole ecosystems off seamounts.
Seamount | Introduction
The Condor Bank fishing involves the bottom (demersal) and also pelagic fish species.
Condor seamount | <a href="Fisheries%20science">Fisheries</a>
Albacore, bigeye and yellowfin aggregate at the seamount, and fishing catch rates are much higher than in the open ocean. The seamount has been used for fishing for a long time.
Capricorn Seamount | Fisheries
Reviews of the local catches have seemed to show no impact of the fishing operation on nearby tuna fishing. However, this is not very surprising, as fishery operations exist nearby with as much as 1000 times the activity. Nevertheless, as tuna spawn locally, there are concerns that the fishing eats away at the juvenile tuna population, which has the potential to seriously hurt fish numbers.
Cross Seamount | Concerns and studies
The ecological conservation of seamounts is hurt by the simple lack of information available. Seamounts are very poorly studied, with only 350 of the estimated 100,000 seamounts in the world having received sampling, and fewer than 100 in depth. Much of this lack of information can be attributed to a lack of technology, and to the daunting task of reaching these underwater structures; the technology to fully explore them has only been around the last few decades. Before consistent conservation efforts can begin, the seamounts of the world must first be mapped, a task that is still in progress. Overfishing is a serious threat to seamount ecological welfare.
Seamount | Conservation
The amount of tuna is thought to depend on conditions on the seamount, and on the current process range of the tuna schools.
Cross Seamount | History of fishing
However, the U.S. Pacific Coast region has an unusually small continental shelf, while the Western Coast region contains islands with no continental shelf. As a result, there are some seamounts within U.S. jurisdiction.
Fishing industry in the United States | Seamounts
Overfishing (as in the rate of depletion) at the Cross seamount appeared to be quite high, causing concerns. However, as much of the population seems to originate elsewhere, this loss is most likely accounted for. Problems with fishery interaction were eliminated, as 90% of the recaptures were in the local area. However, it was not possible to create a model on the overfishing of juveniles, as there was insufficient data to predict this accurately.
Cross Seamount | 1995 tagging project
Suspension feeders, such as gorgonian sea fans and the cold-water corals like Lophelia pertusa, often dominate the rich benthic (seafloor-dwelling) communities. The enhanced abundance and diversity of fauna is not limited to benthic species, as fish are known to aggregate over seamounts. Unfortunately, this knowledge has led to increasing commercial exploitation of seamount fish by the fishing industry, and a number of seamount fish populations have already been depleted. Part of HERMIONE research will assess the threats and impacts of human activities on seamounts, including comparing data from seamounts in different stages of fisheries exploitation to understand more about the impacts of fishing activities., both on target species and non-target species, and their habitats.
Hotspot Ecosystem Research and Man's Impact On European Seas | Seamounts
Demersal fishing is prohibited in the Condor Bank since June 2010 in order to allow the monitoring campaigns continue to be made with reduced human influence. Thus, the Condor will be a reference area, which allows comparison with other areas where fishing occurs regularly, allowing, thus, increase the knowledge of the effects of protection on the exploitation of fish that inhabit the deep waters, particularly for species with commercial interest.
Condor seamount | Scientific Campaigns
However, it is known that the largest percent of the catches are juvenile tuna between 10 and 35 pounds. These fish are probably somewhere between one and two years of age, well below sexual maturity. Fishermen report that the offshore fishing grounds are productive year-round. However, during summer months, large Yellowfin tuna are more abundant. The weight of the catches are estimated to be about 75% "Thunnus obesus" (Bigeye tuna), and 25% "T. albacares" (Yellowfin tuna). According to estimates, about 1 million pounds of Bigeye tuna and 400,000 pounds of Yellowfin were fished from offshore operations from the region in 1995.
Cross Seamount | History of fishing
A common but much smaller fish was "Aldrovandia phalacra". Twenty-six species of cephalopods were collected including squid such as "Mastigoteuthis agassizii" and "Mastigoteuthis magna". Other invertebrates caught by trawls dragged along the seamount surface included 46 species of crustacean such as the prawns "Sergestes spp." and "Acanthephyra spp.", and the shrimp "Pasiphaea spp". Also present was the bank-forming deepwater coral "Lophelia pertusa", which supported a community of worms, hydroids and other corals. Brittle stars, especially "Ophiomusium lymani", were numerous as were the sea urchin "Echinus affinis", the sea star "Neomorphaster forcipatus", mysids and various scyphozoans.
Bear Seamount | Biodiversity
A number of sea animals and fish are encountered on the seamount; active fisheries existed at Vema Seamount and caused the disappearance of some animal species.
Vema Seamount | Introduction
Cross Seamount is well known in fishery and scientific communities for its small but abundant biologic community. Longline fishing ships occasionally fished at Cross Seamount for many years prior to the development of handline fishing, in 1976. The level of fishing remained fairly constant up until the mid 1980. In the late 1980s, the amount of fishing activity at Cross Seamount more than quadrupled; however, it is hard to tell because of limited data. Local tuna populations belong to the same general stocks of tuna that are widely distributed throughout the Pacific. There are no accurate size data collected on the catches from fishing, aside from limited port sampling by the National Marine Fisheries Service.
Cross Seamount | History of fishing
Fishing for tuna with rod and live bait addressed to various species of tuna, such as bigeye tuna ("Thunnus obesus"), and bonito ("Katsowonus pelamis"), is also practised at the Condor Bank, seasonally, between spring and autumn.
Condor seamount | Tuna Fishery
As a result, the seamounts were closed to demersal fishing (collecting fish near the bottom of the ocean, as opposed to pelagic fishing, collecting fish near the surface) beginning 1 January 1997. The original ban was supposed to be lifted 31 December 2010, but was extended until 31 December 2020. Almost a decade into the ban, a 2005 Woods Hole Oceanographic Institution survey found that two of the peaks, Kükenthal and Yakutat, had been stripped bare of both corals and bottom-dwelling animals. However the survey, which covered both the Corner Rise and New England Seamounts, found 270 species of invertebrates and crustaceans, including 70 species unique to the Corner Rise Seamounts.
Corner Rise Seamounts | Introduction
Seamounts are exceptionally important to their biome ecologically, but their role in their environment is poorly understood. Because they project out above the surrounding sea floor, they disturb standard water flow, causing eddies and associated hydrological phenomena that ultimately result in water movement in an otherwise still ocean bottom. Currents have been measured at up to 0.9 knots, or 48 centimeters per second. Because of this upwelling seamounts often carry above-average plankton populations, seamounts are thus centers where the fish that feed on them aggregate, in turn falling prey to further predation, making seamounts important biological hotspots. Seamounts provide habitats and spawning grounds for these larger animals, including numerous fish.
Seamount | Ecological role of seamounts
Tag and release - Tailwater - Tasmanian Seamounts Marine Reserve - Taura syndrome - Tenkara fishing - Tench - Tennessee Wildlife Resources Agency - Tetraodontidae - Texas Rig - TFM (piscicide) - The Field (magazine) - The Golden Mile (Angling) - The Sea of Galilee Boat - The Terror (boat) - Thomas Tod Stoddart - Thresher shark - "Tilapia" - "Tilapia" in aquaculture - Tilefish - Tilting, Newfoundland and Labrador - Topwater fishing lure - Tore Schweder - Tragedy of the commons - Trawling - Trident - Troll (angling) - Trolling tandem streamer fly - Trotline - Trout binning - Trout bum - Trout tickling - Troutmasters - Tullaghmurray Lass - Tuna - Turbot - Turbot War - Turtle excluder device
Index of fishing articles | T
During one survey, a species of cutthroat eel, believed to be found only near Australia, was identified. Corals, echinoderms, and crustaceans make up a large portion of the creatures found on the seamount. These organisms act as indicator species, identifying potential problems in the ecosystem.
New England Seamounts | Biota
Because little was known about the biodiversity of the New England Seamount Chain, an expedition was mounted in 2000. The NOAA National Marine Fisheries Service deep water research vessel R/V Delaware II made 20 exploratory trawls in the vicinity of Bear Seamount and around 274 species were collected. These included 115 species of fish, some of which were rare or had not been recorded in the western North Atlantic before. The roundnose grenadier ("Coryphaenoides rupestris") and the onion-eye grenadier ("Macrourus berglax") were the only fish species of potential commercial importance – they were caught in mid-water at depths of between and were up to a metre in length.
Bear Seamount | Biodiversity
Fishing was the first activity practised in the Condor Bank, for demersal species, fishing with line and hooks (longlines and handlines). The available data for fisheries in the Condor cover the period between 1993 and 2009, and show that, over the years, the vessels using fishing longlines decreased the level of fishing effort, unlike using handline, that are increasing the effort. The vast majority of vessels that fished traditionally in the Condor are of Faial, and in lesser number from Pico island.
Condor seamount | Bottom Fishery
Corals from seamounts are also vulnerable, as they are highly valued for making jewellery and decorative objects. Significant harvests have been produced from seamounts, often leaving coral beds depleted.
Seamount | Conservation
Soviet fishery during the 1970s and 1980s and others have found 150 fish species at Discovery Seamount. Both Japanese and Soviet trawled the seamounts during that time, but there was no commercial exploitation of the resources. Among animals is "Conophora verrucosa", a stylasteride hydrozoan while fish species there include the pygmy flounder; the codling "Guttigadus nudirostre" is endemic to Discovery Seamount. Fossil corals have been recovered in dredges.
Discovery Seamounts | Biology
The seamount was discovered in 1958. Anton Dohrn Seamount hosts a diverse ecosystem characterized by reefs formed by cold water corals, sponges and xenophyophorans, which themselves host a number of animals. It has been affected by human fishing operations, however.
Anton Dohrn Seamount | Introduction
26% to 44% of them could not be identified and are thus believed to be new, and about a third are seemingly present only in the seamount environment. Damage from trawling was also examined, and on the most heavily affected seamounts it had destroyed coral aggregations, removed 46% of species, and reduced net biomass by over half. Following the study, the proposed marine reserve, the "Tasmanian Seamount Community" or "Tasmanian Seamounts Marine Reserve" was created as part of the Environment Protection and Biodiversity Conservation Act 1999. The reserve banned fishing, especially trawling, within an area of . It contained 70 seamounts, a fifth of the known Tasmanian seamounts, all of which were low-trawl areas and thus still in relatively unaffected form.
Tasmanian Seamounts | Ecology
In contrast, the knolls in the group that are affected by bottom trawling are mostly barren, with few coral and a completely different ecosystem. In 2001, witnessing the damage of bottom trawling to seamount communities, 19 seamounts off the coast of New Zealand were closed off to bottom trawling, three of them from the Graveyard group. Timed surveys of the seamounts over the years are being used to examine how well a seamount coral community recovers from the effects of dredging over time.
Graveyard Seamounts | Ecology
the blackspot seabreams would not let the bait hit the bottom...".
Condor seamount | History
Decapods, fish including "Lepidion eques", the eel "Synaphobranchus kaupi" and squat lobsters "Munida sp." have also been encountered.
Anton Dohrn Seamount | Ecology
On June 5, 2020, President Donald Trump signed a proclamation lifting restrictions on commercial fishing at the Monument. The proclamation indicated that the boundaries of the Monument would not be affected. The Proclamation also stated that "appropriately managed commercial fishing would not put the objects of scientific and historic interest that the monument protects at risk," citing that many fish species used as justification for the original protections are highly migratory and that the Magnuson-Stevens Act, and other federal and state laws, provide sufficient protections. The Proclamation was applauded by fishing industry advocates, such as the National Coalition for Fishing Communities.
Northeast Canyons and Seamounts Marine National Monument | Lifting of fishing restrictions
In 1983, , a Royal Australian Navy survey ship, surveyed the area where "Muirfield" was damaged, and charted in detail this previously unsuspected hazard to navigation. The dramatic accidental discovery of the Muirfield Seamount is often cited as an example of limitations in the vertical datum accuracy of some offshore areas as represented on nautical charts, especially on small-scale charts. More recently, in 2005 the submarine ran into an uncharted seamount about 560 kilometers (350 statute miles) south of Guam at a speed of , sustaining serious damage and killing one seaman.
Muirfield Seamount | Introduction
The Secretary General of the United Nations reported in 2006 that 95 percent of damage to seamount ecosystems worldwide is caused by deep sea bottom trawling. A study published in "Current Biology" suggests a cutoff of is a point which ecological damage increases significantly.
Bottom trawling | Deep sea damage
Water temperatures and salinity of the water masses around Tropic Seamount decrease with increasing depth and ripples indicate that strong ocean currents affect the seamount. A number of separate water masses surround the seamount, which originate from regions such as the North Atlantic, the South Atlantic and Antarctica and are stacked over each other. Corals and sponges and more generally sessile fauna cover parts of the eastern and western spurs of Tropic Seamount, forming multicoloured "forests"; among the animals are glass sponges. The bivalve "Rhinoclama teres" and the echinoids "Echinocyamus scaber", "Palaeotropus josephinae", "Peripatagus cinctus" and "Selenocidaris varispina" have been found on this seamount, as are xenophyophorea.
Tropic Seamount | Environment
The diet of "S. thermophilus" varies significantly from seamount to seamount, with the only constant being polychaete worms, which are most important for individuals on Daikoku and Volcano-1 Seamounts. Other populations feed predominantly on crustaceans; the main prey item of "S. thermophilus" on the Nikko Seamount is the alvinocaridid shrimp "Opaepele loihi", and on the Kasuga-2 Seamount they eat mostly palaemonid shrimp. The fish at these sites appear to be "sit and wait" predators, taking slow-moving shrimp that wander too close. By contrast, the fish at the Daikoku Seamount seem to be more active, opportunistic foragers; they do not eat many crustaceans and have been observed scavenging on dying fish that fall to the bottom after coming into contact with the volcanic plumes.
Symphurus thermophilus | Feeding
While overall the species diversity on the seamount is lower than a comparable area on the surface, the species present have grown in greater numbers and have formed larger colonies, to the point that there was little to no bare rock surface on the seamount, and none has been found in expeditionary dives. Some endemism to the seamount has also been noted.
Cobb Seamount | Biology
Some species, including black oreo "(Allocyttus niger)" and blackstripe cardinalfish "(Apogon nigrofasciatus)", have been shown to occur more often on seamounts than anywhere else on the ocean floor. Marine mammals, sharks, tuna, and cephalopods all congregate over seamounts to feed, as well as some species of seabirds when the features are particularly shallow. Seamounts often project upwards into shallower zones more hospitable to sea life, providing habitats for marine species that are not found on or around the surrounding deeper ocean bottom. Because seamounts are isolated from each other they form "undersea islands" creating the same biogeographical interest. As they are formed from volcanic rock, the substrate is much harder than the surrounding sedimentary deep sea floor.
Seamount | Ecological role of seamounts
After a period of explosive activity near the ocean surface, the eruptions slowly die away. With eruptions becoming infrequent and the seamount losing its ability to maintain itself, the volcano starts to erode. After finally becoming extinct (possibly after a brief rejuvenated period), they are ground back down by the waves. Seamounts are built in a far more dynamic oceanic setting than their land counterparts, resulting in horizontal subsidence as the seamount moves with the tectonic plate towards a subduction zone. Here it is subducted under the plate margin and ultimately destroyed, but it may leave evidence of its passage by carving an indentation into the opposing wall of the subduction trench.
Seamount | Geochemistry and evolution
"S. thermophilus" spend most of their time on the sea floor, moving forwards or backwards by undulating their bodies and sometimes burying themselves completely in the substrate. They seem to be attracted to loose sediments, probably related to the uncovering of food, and often congregate in pits. The fish frequently rest atop one another without reaction. The vent communities that co-occur with "S. thermophilus" differs greatly between seamounts. They co-occur with large numbers of the snail "Oenopota ogasawaarna" at the Daikoku Seamount, and with the abundant shrimp "Opaepele loihi" at the Nikko Seamount. They also frequently occur with the crab "Austinograea yunohana", which are found at Nikko, Daikoku, and Kasuga-2.
Symphurus thermophilus | Biology and ecology
In addition there are long gullies formed either by erosional or volcanic processes, as well as parasitic vents and volcanic ridges.
Tropic Seamount | Local
Possibly, as such a seamount or a seamount chain subducted it indented the trenches, forming a re-entrant.
Erimo Seamount | Regional
The Corner Rise Seamounts are a chain of extinct submarine volcanoes in the northern Atlantic Ocean east of the New England Seamounts. Both it and the New England Seamounts were formed when the North American Plate moved over the Great Meteor hotspot 75 million years ago. It is the shallowest seamount in New England, with some of its nineteen highest peaks only 800–900 m deep. Like most seamounts, they attract fish. Over 175 species have been found there, including splendid alfonsino, black cardinal fish, black scabbardfish, and wreckfish. Trawl fishing during the 1970s and 1980s resulted in approximately 20,000 tons of fish being harvested.
Corner Rise Seamounts | Introduction
Big game fishing is an activity practiced in the Azores essentially during the summer, aboard vessels properly equipped for this type of fishing with pole-and-line. The target species are the large pelagic fish such as Blue Marlin ("Makaira nigricans"), swordfish ("Xiphias gladius") and various tuna. Usually after the fight given by the fish, they are subsequently released, unless they constitute potential records. The occurrence of these species in the vicinity of the Condor Bank has been considered a preferred location for this type of fishing, since the 80's, when it became more popular in the Azores.
Condor seamount | <a href="Big-game%20fishing">Big Game fishing</a>
Tension commonly exists between subsistence fishers and commercial fishers who are allowed to harvest rock lobster to measure the ecological growth rate of the species. This opportunity is not offered to subsistence fishers because they do not have the necessary gear. Other activities requiring permits include recreational scuba diving.
Table Mountain National Park Marine Protected Area | Fishing
The observation of sharks in their natural environment is an activity that has a growing economic importance, being generally made by scuba. This activity began experimentally around the Condor in 2009-2010, targeting species such as the blue shark ("Prionace glauca") and the Shortfin Mako ("Isurus oxyrinchus") and as having gained a remarkable importance in the region. The diving trips are made with boats that carry 6-8 divers and sharks are attracted with baits, but without being provided food. Data collected indicate that the Condor seamount is a very important area for this activity.
Condor seamount | Shark diving
The black cardinal fish is subject to commercial fisheries, primarily around seamounts. Based on the FAO fishery statistics, the annual catches worldwide ranged between 1,355 and 4,353 tonnes in 2000 to 2009, most of the fish being taken from the Southwest Pacific (FAO Fishing Area 81). However, according to Watson "et al.", the catches peaked at 10,000 tonnes in the year 2000.
Epigonus telescopus | Fisheries
Crough Seamount (named after the geologist Thomas Crough) is a seamount in the Pacific Ocean, within the exclusive economic zone of Pitcairn. It rises to a depth of and is paired with a taller but overall smaller seamount to the east. This seamount has a flat top and probably formed an island in the past. It is about 7-8 million years old, although a large earthquake recorded at its position in 1955 may indicate a recent eruption. The seamount appears to be part of a long geological lineament with the neighbouring Henderson and Ducie islands, as well as the southern Tuamotus and Line Islands.
Crough Seamount | Introduction
More transient visitors to the seamount included the shortbeard codling ("Laemonema barbatulum") and the blackbelly rosefish ("Helicolenus dactylopterus") which were mostly found on the lower slopes and base of the mound.
Novodinia antillensis | Ecology
"Jasus caveorum" is known from a single seamount in the Foundation Seamounts chain, around , approximately south-east of Pitcairn Island, and west of the Juan Fernández Islands, Chile. The seamount has two peaks at a depth of , separated by a col at a depth of . "J. caveorum" is the only species in the genus whose range is not associated with any land that rises above sea level. "J. caveorum" was discovered in 1995 by the New Zealand fishing vessel FV "David Baker", owned by Southern Seafoods. Commercial lobster traps were laid at various depths, down to ; specimens of "J.
Jasus caveorum | Distribution
Thermophilic and hyperthermophilic microorganisms organism have been found at the seamount. Thermophiles found on the seafloor outside Orca Seamount may indicate that thermal waters of Orca Seamount may travel laterally through geological structures or that currents bring in thermal water from Deception Island, an active volcano.
Bransfield Strait | Description
Environmental groups such as the NRDC and the Center for Biological Diversity criticized the Proclamation. The NRDC cited a July 23, 2018 "Washington Post" article that revealed that in 2017, the Trump administration’s staff intentionally concealed the fact that fishing vessels near the monument in the words of the government, "generated 5% or less of their annual landings from within the monument", which undermined the administration's rationale for reversing the restrictions on commercial fishing. The NRDC also pointed out that the government's own data showed that revenues and catch in the relevant fisheries were higher or the same following the monument's designation.
Northeast Canyons and Seamounts Marine National Monument | Lifting of fishing restrictions
Cross Seamount is a seamount far southwest of the Hawaii archipelago, about equidistant from the cities of Honolulu and Kona. It is one of the numerous seamounts surrounding Hawaii, although unrelated to the Hawaiian hotspot. It is notable for being one of the best studied of the numerous seamounts surrounding Hawaii, as it has been included in numerous biological surveys, most recently in 2007. It is also a site of offshore fishing, for its abundant tuna. The fishery management problems at Cross Seamount are typical of management problems in many fisheries, and its small size makes it a scientifically useful model for the analysis of fishery management.
Cross Seamount | Introduction
The study was also keyed to try to determine the relationship between seamounts and the local fish population.
Cross Seamount | NOAA cruises
Despite being relatively close to the shore of Faial Island, this seamount was only named in 1962. According to written statements, it was the crew of the tuna fishing boat "Condor", commanded by the captain Jaime Medeiros, from Pico Island, who found it, it following indications from an old French nautical chart, which indicated in this area depths with 230 m. The fishermen of that time remember exceptional abundances of fish, wreckfish and blackspot seabreams, especially at the beginning of the exploitation of the bank: "thousands of tones of fish that they got there ... there was so may wreckfish and seabreams… ...
Condor seamount | History
The seamount is elongated in about northeast-south-southwest direction, with ridges radiating from its northern sector and the lower southern sector spreading southwestward like a tongue. This elongation matches the trend of magnetic lineations on the surrounding seafloor, implying that it may be controlled by the surrounding tectonic environment. The submarine slopes of the seamount are quite steep and show two benches at and depth. The seamount has dimensions of on the seafloor. About 15–20 parasitic vents dot the deeper flanks of the seamount and reach height, and small ridges en echelon to Vesteris are found on the southeastern flank. The total volume of the seamount is about .
Vesteris Seamount | Geography and geology
Such a lineament may have been generated by a hotspot; the nearby Easter hotspot is a candidate hotspot.
Crough Seamount | Introduction
Although it is one of over 100 underwater features in the region, Cobb Seamount is the only one known to extend well upwards into the region of the ocean penetrated by light. Like many other seamounts, Cobb Seamount is a local biological hotspot and functions as an "island of stability" for local organisms. It supports an extensive fish population, mostly "Sebastes" species and especially "Sebastes miniatus". Bird life has been noted in the area of its summit, indicating that it is a prime fishing ground. For the complete known species inventory of Cobb Seamount, see Du Preez et al., 2015.
Cobb Seamount | Biology
Gib Brogan, a fisheries analyst at Oceana, said, "Today’s proclamation is another nail in the coffin for both productive fisheries and healthy oceans in New England." Additionally, a senior attorney for the Center for Biological Diversity, an organization that works to protect endangered species, said, "Gutting these safeguards attacks the very idea of marine monuments."
Northeast Canyons and Seamounts Marine National Monument | Lifting of fishing restrictions
Deep sea corals and sponges grow on the Musicians Seamounts; corals identified include "Antipathes", "Acanthogorgia", chrysogorgidae, "Hemicorallium", isididae, "Metalagorgia", "Paracalyptrophora", "Pleurogorgia" and primnoids, while sponges include "Caulophacus", "Hyalostylus", "Poliopogon" and "Saccocalyx". In some places true "coral forests" grow on the seamounts. Animal species observed on the seamounts by remotely operated vehicles include amphipods, anemones, anglerfish, arrow worms, bristlemouths, brittle stars, cephalopods, chirons, codling fish, ctenophores, crinoids, cusk eels, fangtooth fish, halosaurs, jellyfish, larvaceans, piglet squid, polychaetes, ribbon worms, sea cucumbers, sea elephants, sea pens, sea spiders, sea stars, shrimp, siphonophores, spider crabs, squat lobsters, urchins and zoanthids.
Musicians Seamounts | Biology
Fish species encountered at Hebrides Terrace Seamount include Atlantic codling, false boarfish and roundnose grenadier. Overfishing has decimated orange roughy spawning aggregations that formerly occurred at Hebrides Terrace Seamount. Sharks and other fish have also declined since the 1970s.
Hebrides Terrace Seamount | Life
As the fish swims away from the transducer, the distance increases, which shows as progressively deeper pixels. The image to the right shows a school of white bass aggressively feeding on a school of threadfin shad. Note the school of baitfish near the bottom. When threatened, baitfish form a tightly packed school, as the individuals seek safety in the center of the school. This typically looks like an irregularly shaped ball or thumbprint on the fishfinder screen. When no predators are nearby, a school of baitfish frequently appears as a thin horizontal line across the screen, at the depth where the temperature and oxygen levels are optimal.
Fishfinder | Fish arches
This seamount is even shallower than Crough as it reaches a depth of but has a smaller volume of .
Crough Seamount | Local
The greatest threat to the survival of "F. quadrangularis" colonies is demersal fishing activities. This specie has very limited distribution that it is restricted to the deep basins, sensitivity to bottom fishing activities, and low resilience to physical disturbance which make them vulnerable to fishing activities. Trawling often happens at places where Norway lobsters and shrimps present; F. "quadrangularis"is a typical of essential habitat for these species. Since "F. quadrangularis"has a rigid axial rod that is unable to withdraw into the sediment unlike other UK sea pen species, bottom trawling would cause F. "quadrangularis"significant physical disturbance. As a result, "F.
Funiculina quadrangularis | Threats
The seamount suffered a major flank collapse on its southeastern side, over which the present summit was probably formed. The summit supports an ecosystem of mussels, gastropods, tube worms, and others, suggesting that it is an active seeping region.
South Chamorro Seamount | Introduction
Vesteris Seamount was probably known to fishers and seal hunters for over a hundred years as there is a large amount of fish above Vesteris Seamount, which draws both seals and fishers alike to the seamount. The seamount was originally named Vesterisbanken by Eggvin 1963, which showed Vesteris on his bathymetric map.
Vesteris Seamount | History
Seamounts can form in a wide variety of tectonic settings, resulting in a very diverse structural bank. Seamounts come in a wide variety of structural shapes, from conical to flat-topped to complexly shaped. Some are built very large and very low, such as Koko Guyot and Detroit Seamount; others are built more steeply, such as Loihi Seamount and Bowie Seamount. Some seamounts also have a carbonate or sediment cap. Many seamounts show signs of intrusive activity, which is likely to lead to inflation, steepening of volcanic slopes, and ultimately, flank collapse. There are also several sub-classes of seamounts. The first are guyots, seamounts with a flat top.
Seamount | Structure
The seamount is a guyot which rises about to a depth of -, where a flat top is covered by early Cretaceous limestone that contains gastropods, green algae and red algae from that time. Erimo Seamount is cut by normal faults that run parallel to the Kuril-Kamchatka Trench, and the seamount is tilting and beginning to break apart as its subduction starts. It has a volume of about , making it a mid-sized seamount by Pacific Ocean seamount standards, with an northeast-southwest elongated shape and a maximum width of and recognizable rift zones. The crust underneath Erimo contains the magnetic anomaly M8 and has an age of about 120 million years.
Erimo Seamount | Local
Patton Seamount is ecologically vibrant: geologist Randy Keller of the Oregon State University once said "...it's just astonishing how much there is around you. You see rocky outcroppings and there's life everywhere—sponges and sea stars." Patton Seamount, like many other seamounts, serves as an "oasis of life" for resident organisms. Isolated populations found on seamounts like Patton have been shown to have high levels of endemism and specialization, and Patton Seamount is almost completely encrusted in life. Limited-scale fishing operations and scientific investigations were carried around in the 80s and 90s, mostly due to the rough nature of the seamounts, and the difficulty of sampling at such depths.
Patton Seamount | Ecology
Bycatch by unwary fishermen may be a factor for the ongoing decline of the Yangtze finless porpoise. Illegal fishing and hazardous gear, like gillnets, is widely used in the Yangtze river. The preferred habitat of the Yangtze Finless Porpoise overlaps extensively with the usage of gillnets, which makes the species particularly vulnerable to entanglement and subsequent drowning. However, a recent large-scale interview survey conducted in fishing communities along the banks of the Yangtze, by the IUCN, suggests that mortality due to bycatch may have decreased over the past two decades as the porpoise population has declined, and have concluded that gillnetting is unlikely to be the primary cause of their decline.
Narrow-ridged finless porpoise | Fishing
Marine life inhabiting the waters around Lōʻihi is not as diverse as life at other, less active seamounts. Fish found living near Lōʻihi include the Celebes monkfish ("Sladenia remiger"), and members of the Cutthroat eel family, Synaphobranchidae. Invertebrates identified in the area include two species endemic to the hydrothermal vents, a bresiliid shrimp ("Opaepele loihi") of the family Alvinocarididae (described in 1995), and a tube or pogonophoran worm. Dives conducted after the 1996 earthquake swarms were unable to find either the shrimp or the worm, and it is not known if there are lasting effects on these species. From 1982 to 1992, researchers in Hawaiʻi Undersea Research Laboratory submersibles photographed the fish of Lōʻihi Seamount, Johnston Atoll, and Cross Seamount at depths between and .
Lōʻihi Seamount | Macroorganisms
The area is home to rare and endangered species, including sperm whales, fin whales, sei whales and Kemp’s ridley sea turtles.
Northeast Canyons and Seamounts Marine National Monument | Biology and ecology
Areas within the Marine National Monument will remain open to recreational fishing and all military activity. Subsequent to the creation of the Marine National Monument, a 60-day transition period was allowed for all commercial industries, besides the Atlantic Lobster and Deep-Sea Red Crab fisheries, which are permitted to continue fishing in the area for seven years after the creation of the monument. In order to evolve fishing industries into sustainable businesses, the National Oceanic and Atmospheric Administration (NOAA) was tasked to provide commercial fisheries with access to updated vessels and equipment, increasing efficiency and minimizing cost, as well as beneficial services to commercial fisheries, such as stock assessments and marine surveys.
Northeast Canyons and Seamounts Marine National Monument | Legal issues
This causes a different type of fauna to exist than on the seafloor, and leads to a theoretically higher degree of endemism. However, recent research especially centered at Davidson Seamount suggests that seamounts may not be especially endemic, and discussions are ongoing on the effect of seamounts on endemicity. They "have", however, been confidently shown to provide a habitat to species that have difficulty surviving elsewhere.
Seamount | Ecological role of seamounts
This seamount is about 90 x 40 km, it rises from ocean depths of about 4500 m well into the euphotic zone. The summit topography is rather disturbed with a summit plateau ~ 6 x 3 km in about 120 m and a peak reaching up to 55 m below the water surface.
Ampère Seamount | Introduction
The unique ecological condition of the Great Meteor Seamount is shown by the many endemic copepod and nematode species.
Great Meteor Seamount | Ecology
The seamounts in the field are typically less than wide but several kilometres wide; seamounts that are part of a ridge are between high. The total volume of rocks in the seamount province is about .
Rano Rahi seamounts | Geography and geomorphology
There are various habitats and biological communities in the Condor Seamount.
Condor seamount | Habitats
The Graveyard Knolls is a home to over 50 species of fish, dominated by the orange roughy ("Hoplostethus atlanticus"), black oreo ("Allocyttus niger"), and cardinalfish (Apogonidae). Orange roughy in particular aggregate on the Graveyard Knolls for spawning and their visits here have supported a commercial fishery since the mid-1990s. A number of the seamounts are also home to extensive deep water coral forests, made up of "Solenosmilia variabilis" and "Madrepora oculata", both species not known to be of wide extent near New Zealand until camera surveys of Graveyard Knolls in 2001 revealed their extent. These forests offer a home to a diverse invertebrate community that includes squat lobsters, seastars, brittlestars, polychaete worms, and crabs.
Graveyard Seamounts | Ecology
No major threats have been identified for this fish. Most of the countries in whose coastal waters it is found have regulations restricting trawling in certain areas. The bastard sole is uncommon and is not a target species for the fisheries along the coast, but may be caught as bycatch and may then be discarded. The population size and trend of this fish are unknown as no species-specific records are kept, so the International Union for Conservation of Nature has rated its conservation status as being "data deficient".
Microchirus azevia | Status
Complex hydrographical patterns with anticyclones and Taylor columns cause water flow around the summit. Water eddies tend to disrupt this flow. A bottom trawling experiment conducted during research brought up large orange roughy ("Hoplostethus atlanticus") aggregations, as well as bycatch of benthic fauna including sponges, gorgonians, and scleractinian corals.
Sedlo Seamount | Introduction
In 1995, a project to tag the local fish, to analyze the population, was implemented by the NOAA, based on a plan proposed by fishermen in 1992. The first fish were tagged and released in August 1995. The objectives of the project was to investigate the retention rates of tuna on the Cross Seamount, movement patterns of tuna in relation to the fishery patterns, and the interaction between surface and longline fishing. The recovery rate was found to be 5.2% for Yellowfins, and 8.1% for Bigeyes. The longest-distance recapture was a yellowfin tuna tagged on the Cross Seamount in November 1996 and recaptured off the coast of the Baja California peninsula in July 1997.
Cross Seamount | 1995 tagging project
Numerous craters and small volcanic cones dot its flanks which bear evidence of sector collapses.
Cadamosto Seamount | Geography and geomorphology
Human actions are the main cause of the declining Narrow Sawfish populations and ranges. Overutilization, primarily from commercial fisheries, is its biggest threat. Narrow Sawfish populations have likely decreased between 50 and 70% over the last 20 years. The Narrow Sawfish is a high-value target for fishermen. Sawfish are commonly hunted to make shark fin soup or for their rostrums to be displayed as trophies. Most countries have regulations against catching it; however, illegal, unreported, and unregulated fishing remains a threat. Furthermore, the Narrow Sawfish is a common bycatch for fisheries in its geographic range. The toothed rostrum makes it vulnerable to most types of fishing gear, particularly nets.
Knifetooth sawfish | Threats
The two western component areas are zoned as restricted areas, and the eastern is a controlled area.
Southwest Indian Seamounts Marine Protected Area | Zonation
Scour marks have been observed. The currents sweep down the seamount slopes and may act to remove sediment from the seamount surface; this also results in sediments accumulating to form steep slopes that undergo landsliding. Most of the sediments however are transported upslope; those which do end up at the bottom of the seamount form talus deposits around Horizon Guyot.
Horizon Guyot | Present state
Daigo Fukuryū Maru - Daniel Pauly - Dar es Salaam Marine Reserve - Dead zone (ecology) - Deadsticking - Department for Environment, Food and Rural Affairs - Department of Agriculture, Fisheries and Forestry (Australia) - DePuy Spring Creek - Dexter National Fish Hatchery & Technology Center - Dianna Clark - Diawl bach - Discards - Dogger Bank - Dolphin safe label - Domstein - Dongwon-ho 628 - Dory - Double-Heart of Stacked Stones - Downrigger - Dried and salted cod - Dried shrimp - Drift net - Drifter (fishing boat) - Dropline - Dungeness crab - Dworshak National Fish Hatchery
Index of fishing articles | D
The most important feature of the hydrodynamics of the Condor seamount is the presence of a mainstream coming from North, and a pattern of movement with rotation to the right (clockwise) over its Western Ridge. This pattern of movement can capture and retain nutrients and organisms from the outside of the Bank, in the area of 50–60 m above its top. This model can be interrupted by sporadic events of default elimination of movement, which can last up to a few months, encouraging the entry of new materials of the surrounding areas. Thus, the biological productivity of the area may change depending on oceanographic conditions.
Condor seamount | Oceanography
Crinoids and hydrozoans settle on corals. Mobile animals include annelid serpulids, the crab Mediterranean geryon, the fish Atlantic wreckfish, blackbellied angler, rattails and silver roughy, gastropods and shrimps. Most animals on Coral Patch Seamount appear to be suspension feeders. The seamount is heavily fished. Underwater observations have found numerous fishing lines and other debris from human activity on Coral Patch Seamount. Fishing may be the reason why there are few animals on the seamount; a lack of nutrients may be another reason. Rocks dredged from Coral Patch Seamount feature evidence of endolithic microorganisms, i.e., microorganisms that live within the rock.
Coral Patch Seamount | Life
Historically, there have been few examples of efforts to commercialize the mesopelagic zone due to low economic value, technical feasibility and environmental impacts. While the biomass may be abundant, fish species at depth are generally smaller in size and slower to reproduce. Fishing with large trawl nets poses threats to a high percentage of bycatch as well as potential impacts to the carbon cycling processes. Additionally, ships trying to reach productive mesopelagic regions requires fairly long journeys offshore. In 1977, a Soviet fishery opened but closed less than 20 years later due to low commercial profits, while a South African purse seine fishery closed in the mid-1980s due to processing difficulties from the high oil content of fish.
Mesopelagic zone | Fishing
Marine life also flourishes around seamounts that rise from the depths, where fish and other sea life congregate to spawn and feed.
Marine habitats | Seamounts
71% of the species can be confidently classified as cosmopolitan (widespread), and sufficient data exists for 22% of the observed species to strongly suggest that their range is not limited to seamounts. The remaining 7% have only been seen in video footage. Thirteen species have been identified in other areas, but never in other seamounts.
Davidson Seamount | Ecology
Karst features occur on the seamount and are up to deep, including dolines and sinkholes. The outer slopes of MIT Guyot are steep, a typical trait for guyot slopes.
MIT Guyot | Local setting
The species is caught using trawls, seine nets and gill nets and sold fresh, frozen or salted.
False scad | Introduction
Compared to mid-ocean ridge seamounts, subduction zone seamounts generally have more sodium, alkali, and volatile abundances, and less magnesium, resulting in more explosive, viscous eruptions. All volcanic seamounts follow a particular pattern of growth, activity, subsidence and eventual extinction. The first stage of a seamount's evolution is its early activity, building its flanks and core up from the sea floor. This is followed by a period of intense volcanism, during which the new volcano erupts almost all (e.g. 98%) of its total magmatic volume. The seamount may even grow above sea level to become an oceanic island (for example, the 2009 eruption of Hunga Tonga).
Seamount | Geochemistry and evolution
In an illustration of the potent power of flank collapses, a summit collapse on the northern edge of Vlinder Seamount resulted in a pronounced headwall scarp and a field of debris up to away. A catastrophic collapse at Detroit Seamount flattened its whole structure extensively. Lastly, in 2004, scientists found marine fossils up the flank of Kohala mountain in Hawaii (island). Subsidation analysis found that at the time of their deposition, this would have been up the flank of the volcano, far too high for a normal wave to reach. The date corresponded with a massive flank collapse at the nearby Mauna Loa, and it was theorized that it was a massive tsunami, generated by the landslide, that deposited the fossils.
Seamount | Dangers
Minimum recorded depth is 1 m. Maximum recorded depth is 838 m. It is known also from seamounts and knolls.
Capulus ungaricus | Habitat
Fishing nets that have been left or lost in the ocean by fishermen are called ghost nets, and can entangle fish, dolphins, sea turtles, sharks, dugongs, crocodiles, seabirds, crabs, and other creatures. Acting as designed, these nets restrict movement, causing starvation, laceration and infection, and—in those that need to return to the surface to breathe—suffocation.
Wild fisheries | Habitat destruction
Scientific investigations aboard the ATOLL concentrated on one of the most important food chain transitions: the linkages between the early life stages of herring ("Clupea harengus") and their principal prey, the copepods. A major hypotheses of fisheries ecologists is that the microdistribution of prey, the microturbulence of the ocean, or the retention conditions are normally not suited to allow strong year classes of fish to develop. In most years more than 99% of herring larvae do not survive. Occasionally however, physical and biotic conditions are favorable, larval survival is high, and large year-classes result. Research work at the ATOLL investigated the effects of small-scale dynamics on fish feeding and predator avoidance and their correlation to year-class strength.
Antarctic Technology Offshore Lagoon Laboratory | Research