Cross Seamount is a

seamount A seamount is a large geologic landform that rises from the ocean floor that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abru ...

far southwest of the Hawaii archipelago, about equidistant from the cities of

Honolulu Honolulu (; ) is the capital and largest city of the U.S. state of Hawaii, which is in the Pacific Ocean. It is an unincorporated county seat of the consolidated City and County of Honolulu, situated along the southeast coast of the island ...

and Kona. It is one of the numerous seamounts surrounding

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

, although unrelated to the

Hawaiian hotspot The Hawaii hotspot is a volcanic hotspot located near the namesake Hawaiian Islands, in the northern Pacific Ocean. One of the best known and intensively studied hotspots in the world, the Hawaii plume is responsible for the creation of the ...

. 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 A tuna is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae (mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max length: ...

. 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.

Geology

Cross Seamount, a

landform A landform is a natural or anthropogenic land feature on the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography. Landforms include hills, ...

arising from the

ocean floor The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

, is one of the more distant lesser seamounts surrounding the island of Hawaii. The

NOAA The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditio ...

has taken advantage of Cross Seamount’s position, and planted several

weather buoy Weather buoys are instruments which collect weather and ocean data within the world's oceans, as well as aid during emergency response to chemical spills, legal proceedings, and engineering design. Moored buoys have been in use since 1951, while ...

s on the seamount. Very little is known about Cross Seamount's geology, as all of its studies as of March 2009 were of its ecology; however, it was mapped in 1996 by a four-year effort to map all of Hawaii's seafloor in detail.

Biology

History of fishing

Cross Seamount is well known in fishery and scientific communities for its small but abundant biologic community.

Longline fishing Longline fishing, or longlining, is a commercial fishing angling technique that uses a long ''main line'' with baited hooks attached at intervals via short branch lines called ''snoods'' or ''gangions''.handline fishing Handline fishing, or handlining, is a fishing technique where a single fishing line is held in the hands, rather than with a fishing rod like the usual angling. It is a type of angling, and is not to be confused with handfishing, which is catch ...

, 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. Thobe u0

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 The National Marine Fisheries Service (NMFS), informally known as NOAA Fisheries, is a United States federal agency within the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) that is responsible for the stew ...

. 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 Sexual maturity is the capability of an organism to reproduce. In humans it might be considered synonymous with adulthood, but here puberty is the name for the process of biological sexual maturation, while adulthood is based on cultural definitio ...

. Fishermen report that the offshore fishing grounds are productive year-round. However, during summer months, large

Yellowfin tuna The yellowfin tuna (''Thunnus albacares'') is a species of tuna found in pelagic waters of tropical and subtropical oceans worldwide. Yellowfin is often marketed as ahi, from the Hawaiian language, Hawaiian , a name also used there for the closel ...

are more abundant. The weight of the catches are estimated to be about 75% ''

Thunnus obesus The bigeye tuna (''Thunnus obesus'') is a species of true tuna of the genus ''Thunnus'', belonging to the wider mackerel family Scombridae. In Hawaiian, it is one of two species known as ahi, the other being the yellowfin tuna. Bigeye tuna are ...

'' (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. The amount of tuna is thought to depend on conditions on the seamount, and on the current process range of the tuna schools.

Concerns and studies

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.

1995 tagging project

In 1995, a project to tag the local fish, to analyze the population, was implemented by the

, 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 A surface, as the term is most generally used, is the outermost or uppermost layer of a physical object or space. It is the portion or region of the object that can first be perceived by an observer using the senses of sight and touch, and is t ...

and

longline fishing Longline fishing, or longlining, is a commercial fishing angling technique that uses a long ''main line'' with baited hooks attached at intervals via short branch lines called ''snoods'' or ''gangions''. 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.

Overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in th ...

(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.

HARP

Cross seamount hosts a High-frequency Autonomous Acoustic Recording Package (HARP), installed on its summit by the

in April 2005. The purpose of the HARP is to monitor cetaceans that near the seamount, and ultimately to develop ways to work with the marine mammal population using acoustic data. The unit undergoes routine maintenance, and its data is retrieved and analyzed every so often by an NOAA ship.

NOAA cruises

Cross Seamount was cruised by the

in 2006, 2007, and 2008. On November 2, 2006, scientists on the NOAA Ship ''Oscar Elton Sette'', led by chief scientist Michael Musyl, conducted an array of biological experiments off of Kona coast and Cross Seamount. Their goal was to investigate and find ways to reduce the impacts of fishing and improve knowledge of the distribution of tunas, and how they are impacted by fishing activity. It also performed routine maintenance on the HARP. On April 21, 2007, another cruise embarked for Cross Seamount. This cruise's goal, led by Reka Domokos and again on the ''Oscar Elton Settle'', was to test and develop new methods for estimating fish populations using

bioacoustics Bioacoustics is a cross-disciplinary science that combines biology and acoustics. Usually it refers to the investigation of sound production, dispersion and reception in animals (including humans). This involves neurophysiological and anatomical b ...

, specifically that of the

bigeye tuna The bigeye tuna (''Thunnus obesus'') is a species of true tuna of the genus '' Thunnus'', belonging to the wider mackerel family Scombridae. In Hawaiian, it is one of two species known as ahi, the other being the yellowfin tuna. Bigeye tuna are ...

. The study was also keyed to try to determine the relationship between seamounts and the local fish population. On April 15, 2008, another cruise embarked, to study the bigeye tuna population and their migratory patterns. The researchers, again on the ship ''Oscar Elton Sette'', investigated the seamount waters, measuring the number of bigeye tuna and the prey species that frequent the area.

References

{{reflist Seamounts of the Pacific Ocean