The Large-Scale Deployment of Fish Aggregation Devices Alters Environmentally-Based Migratory Behavior of Skipjack Tuna in the Western Pacific Ocean
نویسندگان
چکیده
Fish aggregation devices (FADs) have been used extensively in the tuna purse seine fishery since the 1980s. This long-term modification of natural habitat has generated discussions as to whether FADs impact movement patterns of tuna species. We examined this question using data collected from the skipjack tuna (Katsuwonus pelamis) fishery. We used the longitudinal gravitational center of catch (G) to examine temporal variability in skipjack movement in the Western and Central Pacific Ocean, and related this to El Niño Southern Oscillation (ENSO) events. We found that in most cases G for free-swimming school sets changed with the onset of ENSO events, while G for floating-object-associated school sets remained relatively constant. This suggests that skipjack exhibit distinguishable behavioral strategies in response to ENSO events: they either react by moving long distances or they associate with floating objects. There has been no previous attempt to evaluate the interaction between FADs and the environmentally-determined movement of skipjack; this study shows evidence of an interaction, which should be considered when managing skipjack populations.
منابع مشابه
SCIENTIFIC COMMITTEE FOURTH REGULAR SESSION 11-22 August 2008 Port Moresby, Papua New Guinea ACOUSTIC IMAGING, VISUAL OBSERVATIONS, AND OTHER INFORMATION USED FOR CLASSIFICATION OF TUNA AGGREGATIONS ASSOCIATED WITH FLOATING OBJECTS IN THE PACIFIC OCEAN WCPFC-SC4-2008/FT-IP-2
Purse seiners operating in the Pacific Ocean catch large quantities, in various proportions, of skipjack, yellowfin, and bigeye tunas associated with floating objects, in particular fish-aggregating devices (FADs). There is concern about the high fishing mortality rates on small bigeye and yellowfin tunas associated with floating objects from purse-seine fisheries, and the negative impact on su...
متن کاملInter-american Tropical Tuna Commission Third Meeting of the Scientific Working Group Review of Stock Assessments Chairman’s Report (revised)
A1 Draft: The fishery for tunas and tuna-like fishes in the eastern Pacific Ocean in 2001, and outlook for 2002 A2 Draft: Status of yellowfin tuna in the eastern Pacific Ocean in 2001 and outlook for 2002 A3 Draft: Status of skipjack tuna in the eastern Pacific Ocean in 2001 and outlook for 2002 A4 Draft: Status of bigeye tuna in the eastern Pacific Ocean in 2001 and outlook for 2002 A5 Draft: ...
متن کاملInter-american Tropical Tuna Commission Scientific Working Group 2 Meeting Review of Stock Assessments
AGENDA 1. Welcome, introductions, consideration of agenda 2. Review of stock assessments: a. Methods b. Species composition sampling progress c. Results i. Yellowfin ii. Skipjack iii. Bigeye iv. Bluefin (paper only) v. Blue marlin vi. Albacore (paper only) vii. Others 3. Ecosystem modeling 4. Summary and recommendations 5. Other business 6. Adjournment DOCUMENTS A1 The surface fishery for tunas...
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Spawning activity of male skipjack tuna Katsuwonus pelamis was examined from May 2005 to December 2007 in the tropical western and central Pacific Ocean. Testis maturity was classified into five stages (i.e., immature, early maturation, mid maturation, late maturation, and regression) on the basis of histological observation. The estimated minimum size at first maturity was 35.5cm FL and the si...
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