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
spiny lobster, mackerel, red king crab, red snapper, tuna Red snapper, tuna, Orange roughy, and perch Spiny lobster, mackerel, red king crab, red snapper Mackerel, tuna, Orange roughy, perch and others.
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
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.
assistant
any fish you can mention?
user
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
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
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
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
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
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 Condor Bank fishing involves the bottom (demersal) and also pelagic fish species.
Condor seamount | <a href="Fisheries%20science">Fisheries</a>
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
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
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
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
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
Decapods, fish including "Lepidion eques", the eel "Synaphobranchus kaupi" and squat lobsters "Munida sp." have also been encountered.
Anton Dohrn Seamount | Ecology
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
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
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
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
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
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
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 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
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
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
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
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
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
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
the blackspot seabreams would not let the bait hit the bottom...".
Condor seamount | History
The seamount chain provides a unique habitat for deep sea marine creatures. Coral formations grow on the rocky outcrops, resembling underwater forests that provide shelter for invertebrates and fish. Due to the expense and difficulties of studying the deep ocean, little was known of the creatures that inhabited the New England Seamounts. In fact, before recent expeditions, there was only one known coral species in the entire chain. Since 2000, marine biologists, during various exploratory studies, have caught and classified over 203 species of fish and 214 species of invertebrates on the Bear Seamount. This range of diversity suggests that other seamounts may harbour more unknown macro-organisms.
New England Seamounts | Biota
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
"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
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
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
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
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
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
Possibly, as such a seamount or a seamount chain subducted it indented the trenches, forming a re-entrant.
Erimo Seamount | Regional
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
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
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
Noroît Seamount's marine habitats are well researched. Investigations by the research vessel EV "Nautilus" in 2014 found a variety of stony corals ("scleractinians"), octocorals, and sponges. Corals created habitat for brittle stars, squat lobsters and sea snails. In the sea depth there are variety of fish — Acanthonus armatus, Bathypterois phenax, Bembrops, Conger esculentus, Coryphaenoides, Hexanchus griseus, Lepidion, Luciobrotula corethromycter, and Polymixia lowei.
Noroit Seamount | Flora and fauna
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
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
The Bear Seamount is the first guyot in a chain of about 30 extinct volcanoes extending in a straight line south-eastwards from the edge of the continental shelf near Woods Hole, Massachusetts to north-east of Bermuda. These seamounts resulted from the movement of a mantle plume hotspot. This hotspot is now under the Great Meteor Seamount. The chain rises about above the surrounding Sohm Abyssal Plain. Over time they have been eroded and have developed flat table-like summits surrounded by slopes with an inclination of about 20°. The currents in the vicinity of the Bear Seamount include the warm water Gulf Stream flowing towards the north east, the deep boundary current flowing along the continental shelf towards the south west, and the deep, icy cold Arctic bottom water that flows past the lower flanks of the chain.
Bear Seamount | Formation
Octocorals grow on Cadamosto Seamount and are populated by crabs, fish and other animals.
Cadamosto Seamount | Life
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
In addition there are long gullies formed either by erosional or volcanic processes, as well as parasitic vents and volcanic ridges.
Tropic Seamount | Local
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
MIT Guyot formed during the Cretaceous about 123 million years ago. Based on paleomagnetic data, the seamount formed at a latitude of 11.5 ± 2.3 degrees south and is at least 118 million years old. A paleolatitude of 32.8 degrees south may also be possible and would be consistent with that of the Macdonald hotspot.
MIT Guyot | Geologic 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
They average ± in volume, but range from to . In addition to the eight main seamounts, there is a scattered disk of minor volcanic cones and flows about southeast of the chain.
President Jackson 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>
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
In addition, the bobtail squids "Rossia" and "Sepiola" and the ram's horn squid have been found at Echo Bank. Shoals of fish were frequently observed on the seamount. In 1960–1970, snapper fisheries at Echo Bank were replaced by cephalopod fisheries.
Echo Bank | Environment
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
Green Seamount is not very biologically diverse. The only fauna observed at its hydrothermal sites were single-celled, fan-shaped xenophyophores, and some shrimp. Still, marks of biological life were plentiful wherever sediments were or more deep. The xenophyophores in particular were of a type that was found on many of the seamounts in the eastern Pacific region. "Alvin" took two samples, a sponge of the Hexactinellid family and barnacles of the Sessilia order, back to the surface for analysis.
Green Seamount | Biology
Whether there was Holocene activity 5,000–6,000 years ago or present-day hydrothermal activity is unclear. A variety of lifeforms are found both on Vesteris Seamount and within its rocks. Layers of sponges and bryozoans cover the upper parts of the seamount and form structures like mounds. This ecosystem has been compared to coral reefs.
Vesteris Seamount | Introduction
Several new species have been discovered on the Tarava seamounts, such as the "Lophiodes iwamotoi" anglerfish, the cone snail "Profundiconus tarava", the majoid crab "Samadinia longispina" and pectinoid "Parvamussium vesiculosum". Other species found there are "Propeamussium watsoni" together with five other pectinoids, and tonnoidean gastropods.
Tarava seamounts | Biology
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 large guyot rises over from the eastern flank of the Tonga Trench to a depth of . It features a wide flat top at depth, which tilts gently westwards. A north-northeast trending scarp separates the flat top from another, shallower flat-topped knoll on the eastern side of the flat top which also tilts westwards; the shallowest point of the seamount lies on this knoll. Additional volcanic cones dot the slopes of Capricorn Seamount. At its foot the seamount is wide. The crust underneath the seamount is 75-95 million years old and is thickened, perhaps by the seamount's lava flows.
Capricorn Seamount | Geomorphology and geology
The surfaces of Horizon Guyot are inhabited by many organisms. Fish found on Horizon Guyot include batfish, bathypteroids, chimeras, morids, sharks and synaphobranchid eels. Brittle stars, chaetognatha (arrow worms), copepods, corals, crustaceans, hydroids, loricifera, molluscs, nematodes, nemertinea, ophiuroids, ostracods, polychaetes, sipuncula, squat lobsters, vermes and xenophyophorans make up the bulk of the fauna on Horizon Guyot today. At least 29 macrofaunal species have been found. Other lifeforms presently active on the seamount are barnacles, crinoids, echiurids, enteropneusts (acorn worms), gorgonians, holothuroids (sea cucumbers), pennatulids (sea pens), sponges and starfish. Unidentified stalk or twig-like creatures have also been observed on the platform, which are among the most common lifeforms there.
Horizon Guyot | Ecology
The New England Seamounts were once at or above sea level. As time passed, however, and the chain moved farther away from the New England hotspot, the crust cooled and contracted, and the chain sank into the ocean. All the peaks are now a kilometer or more below the surface.
New England Seamounts | Formation
Channels, debris flow fronts and levees decorate its slopes. Noticeable ridges emanate from the east-southeastern, southwestern, west-northwestern and north-northeastern corners of the seamount; they appear to be rift zones, and flank cones are found on the eastern slopes. The southern slopes feature slump deposits, and the entire seamount is surrounded by a sediment fan. The volume of the entire seamount is about . Two large seamounts lie west and southwest of Takuyo-Daisan with a smaller seamount between the two; Takuyo-Daini is the western one and Jensen seamount the south-western one. The seafloor underneath Takuyo-Daisan has an age of 143 million years.
Takuyo-Daisan | Local
A total of 8 core samples have been gathered, with ages ranging from Pliocene to Late Cretaceous. No radiometric dates are available for the seamount, but it may of Early Cretaceous time. Over 150 invertebrates have been collected in total from Bear, Manning, and Muir seamounts. Ophiuroids and goose barnacles are the most abundant animal found on the seamount, as is "Asteroshchema sp.", a basket star. Paragorgia have also been observed. Genetic tests on the specimens collected indicated that Muir Seamount is the most genetically isolated of the four.
Muir Seamount | Introduction
Corals and squat lobsters have been found on the seamount. Ophiuroids, most of which are symbiotic with corals and sponges, live on the seamount and its flanks, and the seamount features substantial deposits of ferromanganese and phosphorite ores. In 2014, China obtained a contract with the International Seabed Authority allowing for exploration of Pako Guyot for cobalt crusts.
Pako Guyot | Introduction
South Chamorro Seamount is host to a variety of fauna, including mussels, gastropods, tube worms, and galatheid crabs. A borehole observatory on the summit produced 20,000 litres of microbially-altered fluid per day for study. These organisms are supported by low-temperature springs from the fissures surrounding the summit zone. The mussels are probably of the genus Bathymodiolus, which require a high concentration of methane in their food source. The fluid composition and the biological community suggests that the summit region is an active cold seep region.
South Chamorro Seamount | Ecology
Dredged carbonate samples from the top of the seamount contained porites and several other corals, covered by coralline algae at shallow to medium depth. Also present were Amphistegina, red algae (mainly Lithothamnion and Sporolithon), lepidocyclines, bryozoans, and coralline at deeper depths. The recorded lepidocyclinids indicate an Early Miocene age for the drowned carbonate platforms found on the seamount, at about .
Koko Guyot | Ancient ecology
This seamount is even shallower than Crough as it reaches a depth of but has a smaller volume of .
Crough Seamount | Local
The black cardinal fish is a deepwater bentho-pelagic fish that is found on continental slopes, undersea ridges and seamounts in the northern Atlantic, ranging from Iceland to the Canary Islands and the Corner Rise Seamounts. It is also found in the southeastern Atlantic, including the Walvis Ridge off southwestern Africa, the Indian Ocean and the southwestern Pacific Ocean.
Epigonus telescopus | Distribution and habitat
Such a lineament may have been generated by a hotspot; the nearby Easter hotspot is a candidate hotspot.
Crough Seamount | Introduction
Large landslides and late volcanic activity affected the seamount, cutting large scars into its flanks and forming cones on its summit plateau, respectively. Volcanic activity at Tropic Seamount commenced almost 120 million years ago and ended about 60 million years ago. Later, sedimentation commenced on the seamount leading to the deposition of manganese crusts and pelagic sediments; iron and manganese accumulated in crusts over time beginning a few tens of millions of years ago.
Tropic Seamount | Introduction
Among the animals found on the Foundation Seamounts are the seaperch "Helicolenus lengerichi", the striped trumpeter, decapods including the genus "Paralomis" and the species "Shinkaia crosnieri", and the spiny lobster "Jasus caveorum". The Foundation Seamounts are a candidate for an Ecologically or Biologically Significant Area. The Foundation-Pacific-Antarctic-Ridge intersection is the first known deep sea hydrothermal system from the southern hemisphere. Hydrothermal communities found at the active hydrothermal venting sites include "Bathymodiolus", bythograeids, "Munidopsis", "Neolepas", polychaetes, snails and zoarcid fish. Filter feeders are found as well and include crinoids and hexactinellid sponges. Actinians, coryphaenid fish and serpulids round out the local fauna.
Foundation Seamounts | Biology
Dredging has yielded both vesicular and porphyritic basalt. Phenocrysts identified include clinopyroxene, olivine and plagioclase. Carbonates and hyaloclastites have also been found, and some samples were covered with manganese crusts and palagonite. Hydrothermal iron crusts have also been found.
Crough Seamount | Composition
The seamount is named after the research vessel and is also known as Horizon Ridge, Horizon Tablemount, Gora Khorayzn and . During the Deep Sea Drilling Project, the drill cores called Site 44 and Site 171 were taken on Horizon Guyot in 1969 and 1971, respectively; a further drill core was obtained north of the seamount at Site 313 in 1973. This seamount is the best studied seamount of the Mid-Pacific Mountains and more is known about its morphology than any other seamount of the Mid-Pacific Mountains.
Horizon Guyot | Name and research history
The Bear Seamount is a guyot or flat-topped underwater volcano in the Atlantic Ocean. It is the oldest of the New England Seamounts, which was active more than 100 million years ago. It was formed when the North American Plate moved over the New England hotspot. It is located inside the Northeast Canyons and Seamounts Marine National Monument, which was proclaimed by President of the United States Barack Obama to protect the seamount's biodiversity.
Bear Seamount | Introduction
The study was also keyed to try to determine the relationship between seamounts and the local fish population.
Cross Seamount | NOAA cruises
"Aldrovandia phalacra" is a deep water fish, living at depths of . It is found in warm waters on the continental shelf, around islands and in the vicinity of seamounts. Its range includes the Eastern Atlantic between 15° N and 45° N, the Western Atlantic at similar latitudes, the coastal shelves of South Africa and Brazil, the Indian Ocean and the vicinity of Hawaii. During exploratory trawls round the Bear Seamount, it was the commonest species of fish.
Aldrovandia phalacra | Distribution
The seamount lies in the Mid-Pacific Mountains on their southern side and is a submarine mountain with a flat top that rises over to a depth of -. The flat top has an oval shape and a surface area of ; it is characterized by a limestone dome on the summit, buried beneath sediments; in turn a volcanic hill is buried within the limestone dome. The top of the seamount has a hummocky appearance which has been interpreted as a sediment cover and its southeastern sector has a bank-like shape that resembles that of an atoll. Cape Johnson Guyot is considered to be of Middle Cretaceous age with an age of 120 million years reported and shallow-water fossils were emplaced on it at that time.
Cape Johnson Guyot | Geography and geology
Henry Seamount is located within the Canary Current Large Marine Ecosystem. Deepwater corals, holothurians, red worms, starfish, gastropods and xenophyophore, a coral stem and shell fragments have also been reported. Underwater cameras have observed "graveyards" of thousands of clams on the seamount. The occurrence of "Abyssogena southwardae" at Henry Seamount has been reported.
Henry Seamount | Biology
These include the Hawaiian (Emperor), Mariana, Gilbert, Tuomotu and Austral Seamounts (and island groups) in the north Pacific and the Louisville and Sala y Gomez ridges in the southern Pacific Ocean. In the North Atlantic Ocean, the New England Seamounts extend from the eastern coast of the United States to the mid-ocean ridge. Craig and Sandwell noted that clusters of larger Atlantic seamounts tend to be associated with other evidence of hotspot activity, such as on the Walvis Ridge, Bermuda Islands and Cape Verde Islands. The mid-Atlantic ridge and spreading ridges in the Indian Ocean are also associated with abundant seamounts.
Seamount | Grouping
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
Fossilised bones from extinct whale species have been recovered from the terraced continental slope from depths beyond in this area.
Southwest Indian Seamounts Marine Protected Area | History
Otherwise, seamounts tend not to form distinctive chains in the Indian and Southern Oceans, but rather their distribution appears to be more or less random. Isolated seamounts and those without clear volcanic origins are less common; examples include Bollons Seamount, Eratosthenes Seamount, Axial Seamount and Gorringe Ridge.
Seamount | Grouping
Guyots cover a total area of and have an average area of , more than twice the average size of seamounts. Nearly 50% of guyot area and 42% of the number of guyots occur in the North Pacific Ocean, covering . The largest three guyots are all in the North Pacific: the Kuko Guyot (estimated ), Suiko Guyot (estimated ) and the Pallada Guyot (estimated ).
Seamount | Geography
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 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
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
Between 700 and 900 m depth there are large aggregations of sponges in the Condor seamount. These aggregations are dominated by the presence of glass sponge ("Pheronema carpenteri") and are also considered as habitats of conservation importance.
Condor seamount | Aggregations of sponges
The seamount is very close to the "V"-shaped bend in the Hawaiian-Emperor seamount chain, and thus would be useful in understanding the exact age of the bend. Although few dredge samples are available, they have all been reliably dated at 47 million years (Sharp and Clague, Science, 313, 1281-84, 2006), during the Eocene epoch of the Paleogene period. During the cruise SO112 of the "R/V SONNE", high resolution bathymetric mapping was conducted, showing that Daikakuji is nearly in diameter and nearly in height, with a summit lying underwater. Because of its flat capped top, Daikakuji is considered a guyot. A smaller, younger, secondary guyot just east of the main mass overlaps its slope.
Daikakuji Guyot | Geology
The floor of the seamount is generally covered by a dense layer of seaweed, dominated by the "Cystoseira" species, a seaweed found in deeper areas. In shallower depths less than from the surface there are populations of "Laminaria" (large colonies of chestnut seaweeds). The Department of Oceanography and Fisheries at the University of the Azores (Ponta Delgada) monitors and studies these species annually through scientific missions to the reef and surrounding islets.
Dollabarat | Biome
The Newfoundland Seamounts are a group of seamounts offshore of Eastern Canada in the northern Atlantic Ocean. Named for the island of Newfoundland, this group of seamounts formed during the Cretaceous period and are poorly studied. The Newfoundland Seamounts appear to have formed as a result of the North American Plate passing over the Azores hotspot. Scruncheon Seamount in the middle of the chain has given an isotopic date of 97.7 ± 1.5 million years for the Newfoundland Seamounts. This indicates that the Newfoundland Seamounts were volcanically active in the earliest Cenomanian stage.
Newfoundland Seamounts | Introduction
The seamount was probably formed by a mantle diapir with eruptions occurring along fissures and in association with the Mid-Atlantic Ridge. It probably began to form no less than 70-75 million years ago, as reefs of that age containing coccoliths, corals and foraminifers have been found on the seamount; they also indicate that the seamount was emergent at that time. The seamount may have risen between above sea level before thermal subsidence lowered it to its current depth. Corals, golden corals, sea stars and sponges have been found at Krylov Seamount.
Krylov Seamount | Geology and geochronology
The seamount was named for the 58th emperor of Japan, Emperor Koko (A.D. 885-887) by geologist Thomas Davies and his colleagues in 1972, based on the results from a bathymetric expedition and contents of two dredge huals, led by Thomas Washington and undertaken with the ship "Aries-7". The seamount is elongate in shape, aligned northwest-southeast (the same direction as the chain), and has a gentle slope and a large, flat top. Koko Seamount also has a lot of small reefal bodies on its slopes. It rises from the abyssal floor about in height. A prominent south-trending ridge extends about from the summit area in the direction of Kimmei Seamount, to the southeast.
Koko Guyot | Geology and characteristics
Shoals of young rockfish were seen on Bowie's steep flanks. Scientist Bill Austin of Khoyatan Marine Lab in the Northeast Pacific examined a video made during the National Geographic dives to identify the benthic flora and fauna of Bowie Seamount. From the video, Austin recognized some of the most noticeable invertebrates and noted that a few species generally occurring in the intertidal zone and in shallow subtidal environments were found deeper than might normally be expected, and were bigger than normal.
Bowie Seamount | Diving explorations and studies
Minimum recorded depth is 1 m. Maximum recorded depth is 838 m. It is known also from seamounts and knolls.
Capulus ungaricus | Habitat
The New England Seamounts is a chain of over twenty underwater extinct volcanic mountains known as seamounts. This chain is located off the coast of Massachusetts in the Atlantic Ocean and extends over 1,000 km from the edge of Georges Bank. Many of the peaks of these mountains rise over 4,000 m from the seabed. The New England Seamounts chain is the longest such chain in the North Atlantic and is home to a diverse range of deep sea fauna. Scientists have visited the chain on various occasions to survey the geologic makeup and biota of the region. The chain is part of the Great Meteor hotspot track and was formed by the movement of the North American Plate over the New England hotspot.
New England Seamounts | Introduction
There are various habitats and biological communities in the Condor Seamount.
Condor seamount | Habitats
Non-hydrothermal chemical alteration has taken place and has formed carbonate, celadonite, chlorite, hematite, prehnite, quartz, smectite and rare zeolites. Thick ferromanganese deposits were recovered from the seamount in 1992 by the and are found especially on the western flank but also in the summit region, often over partly consolidated sediments. They have the appearance of a black crust. Components include carbonate fluorapatite, goethite and manganese dioxide as well as minor calcite and quartz; the crusts which occur on the Canary Islands Seamounts including at Tropic Seamount reach thicknesses of and are rich in cobalt and other elements of industrial importance.
Tropic Seamount | Composition
The name Coral Patch Seamount refers to the presence of cold water corals on the seamount. Their occurrence there was reported first in 1878, five years before the actual discovery of the seamount. They are only sparse on Coral Patch Seamount, probably due to lack of nutrients. A number of other submarine animals including fish have been observed.
Coral Patch Seamount | Introduction