Cross Seamount
Encyclopedia
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.
arising from the ocean floor, is one of the more distant lesser seamounts surrounding the island of Hawaii
. The NOAA has taken advantage of Cross Seamount’s position, and planted several weather buoy
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.
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
. 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
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. The amount of tuna is thought to depend on conditions on the seamount, and on the current process range range of the tuna schools.
and longline fishing.
{| class="wikitable"
|-
| colspan="1" | Capture Rates
| colspan="1" | Recovery Rates
|-
|
{| class="wikitable"
|-
|
Bigeye
Yellowfin
OTC
Non-OTC
OTC
Non-OTC
Location
Cross Seamount
567
1360
1
867
Buoy 2
474
316
2
321
Buoy 3
0
428
0
85
Buoy 4
0
199
0
98
Other Buoy
0
55
0
86
Total
1041
2358
3
1457
SPP Total
3399
1460
Grand Total
4859
|
{| class="wikitable"
|-
|
Bigeye
Yellowfin
OTC
Non-OTC
OTC
Non-OTC
Location
Cross Seamount
44
33
0
86
Buoy 2
69
5
0
12
Buoy 4
1
2
0
5
Other Buoy
0
6
0
4
Other
2
4
1
8
Unknown
2
8
0
2
Total
118
58
1
117
SPP Total
176
118
Grand Total
294
|}
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
(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.
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
, specifically that of the bigeye tuna
. 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.
Seamount
A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface , and thus is not an island. These are typically formed from extinct volcanoes, that rise abruptly and are usually found rising from a seafloor of depth. They are defined by oceanographers as...
far southwest of the Hawaii archipelago
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
, about equidistant from the cities of Honolulu and Kona
Kona District, Hawaii
Kona is the name of a moku or district on the Big Island of Hawaii in the State of Hawaii. In the current system of administration of Hawaii County, the moku of Kona is divided into North Kona District and South Kona District . The term "Kona" is sometimes used to refer to its largest town,...
. It is one of the numerous seamounts surrounding Hawaii
Hawaii (island)
The Island of Hawaii, also called the Big Island or Hawaii Island , is a volcanic island in the North Pacific Ocean...
, 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
Commercial fishing
Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often pursue fish far into the ocean under adverse conditions...
, for its abundant tuna
Tuna
Tuna is a salt water fish from the family Scombridae, mostly in the genus Thunnus. Tuna are fast swimmers, and some species are capable of speeds of . Unlike most fish, which have white flesh, the muscle tissue of tuna ranges from pink to dark red. The red coloration derives from myoglobin, an...
. 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 landformLandform
A landform or physical feature in the earth sciences and geology sub-fields, comprises a geomorphological unit, and is largely defined by its surface form and location in the landscape, as part of the terrain, and as such, is typically an element of topography...
arising from the ocean floor, is one of the more distant lesser seamounts surrounding the island of Hawaii
Hawaii (island)
The Island of Hawaii, also called the Big Island or Hawaii Island , is a volcanic island in the North Pacific Ocean...
. The NOAA has taken advantage of Cross Seamount’s position, and planted several weather buoy
Weather buoy
Weather buoys are instruments which collect weather and ocean data within the world's oceans, as well as aiding during emergency response to chemical spills, legal proceedings, and engineering design. Moored buoys have been in used since 1951, while drifting buoys have been used since 1979...
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.
History of fishing
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 ishard to tell because of limited data.
There are no accurate size data collected on the catches from fishing, aside from limited port sampling
Port
A port is a location on a coast or shore containing one or more harbors where ships can dock and transfer people or cargo to or from land....
by the National Marine Fisheries Service
National Marine Fisheries Service
The National Marine Fisheries Service is a United States federal agency. A division of the National Oceanic and Atmospheric Administration and the Department of Commerce, NMFS is responsible for the stewardship and management of the nation's living marine resources and their habitat within the...
. However, it is known that the largest percent of the catches are juvenile
Juvenile (organism)
A juvenile is an individual organism that has not yet reached its adult form, sexual maturity or size. Juveniles sometimes look very different from the adult form, particularly in terms of their colour...
tuna between 10 and 35 pounds. These fish are probably somewhere between one and two years of age, well below sexual maturity
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
. Fishermen report that the offshore fishing grounds are productive year-round. However, during summer months, large Yellowfin tuna
Yellowfin tuna
The yellowfin tuna is a species of tuna found in pelagic waters of tropical and subtropical oceans worldwide.Yellowfin is often marketed as ahi, from its Hawaiian name ahi although the name ahi in Hawaiian also refers to the closely related bigeye tuna. The species name, albacares can lead to...
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
The yellowfin tuna is a species of tuna found in pelagic waters of tropical and subtropical oceans worldwide.Yellowfin is often marketed as ahi, from its Hawaiian name ahi although the name ahi in Hawaiian also refers to the closely related bigeye tuna. The species name, albacares can lead to...
(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 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 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 surfaceSurface lure
A surface lure is a fishing lure designed to waddle, pop, lock, drop, pulse, twitch or fizz across the surface of the water as it is retrieved, and in doing so imitate surface prey for fish such as mice, lizards, frogs, cicadas, moths and small injured fish....
and longline fishing.
{| class="wikitable"
|-
| colspan="1" | Capture Rates
| colspan="1" | Recovery Rates
|-
|
{| class="wikitable"
|-
|
Bigeye
Yellowfin
Location
|
{| class="wikitable"
|-
|
Bigeye
Yellowfin
Location
|}
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
Baja California Peninsula
The Baja California peninsula , is a peninsula in northwestern Mexico. Its land mass separates the Pacific Ocean from the Gulf of California. The Peninsula extends from Mexicali, Baja California in the north to Cabo San Lucas, Baja California Sur in the south.The total area of the Baja California...
in July 1997.
Overfishing
Overfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
(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 NOAA 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 NOAA 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
Kona District, Hawaii
Kona is the name of a moku or district on the Big Island of Hawaii in the State of Hawaii. In the current system of administration of Hawaii County, the moku of Kona is divided into North Kona District and South Kona District . The term "Kona" is sometimes used to refer to its largest town,...
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
Bioacoustics is a cross-disciplinary science that combines biology and acoustics. Usually it refers to the investigation of sound production, dispersion through elastic media, and reception in animals, including humans. This involves neurophysiological and anatomical basis of sound production and...
, specifically that of the bigeye tuna
Bigeye tuna
The bigeye tuna, Thunnus obesus, is an important food fish and prized recreational game fish. It is a true tuna of the genus Thunnus, belonging to the wider mackerel family Scombridae....
. 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.