Lutcavage and Kraus: Feasibility of photographic assessment of Thunnus thynnus 



503 



are believed to exhibit the most rigidly defined spa- 

 tial structures in schooling fishes (Partridge et al., 

 1983). If relations between the surface structure of 

 schools and total biomass were known, surface counts 

 could be adjusted to include an estimate of biomass. 



In future studies, on-board data loggers might be 

 used to give accurate records of search effort and 

 survey tracks and possibly to determine fish size 

 through direct altimetry from phototelemetry and 

 GPS data. Hydroacoustic trials, Lidar, or remotely 

 operated vehicle analysis undertaken alongside sein- 

 ing operations may provide additional groundtruth 

 information that would allow derivation of indices of 

 abundance (Petit et al., 1992). 



In spite of limitations faced in the 1993 feasibility 

 study, this preliminary aerial survey provided infor- 

 mation on counts, distribution, and schooling char- 

 acteristics of giant and large-medium bluefin tuna. 

 Direct photographic surveys to obtain minimum 

 counts of giant bluefin tuna may be a practical 

 method of obtaining real-time measures of their rela- 

 tive abundance in New England waters. 



Acknowledgments 



This research was conducted under an agreement be- 

 tween the New England Aquarium and the East Coast 

 Tuna Association (ECTA). The following pilots partici- 

 pated in data collection, served as the backbone of this 

 survey, and provided valuable advice on fishery opera- 

 tions: Marc Avila, John Betzner, Wayne Davis, Jim Gly- 

 man, Roger Hillhouse, Ted Malley, Jonathan Mayhew, 

 Norman St. Pierre, and Trip Wheeler. Richard Ruais, 

 ECTA, and participating boat captains supported and 

 funded the study and contributed organizational sup- 

 port. Grant MacNally served as photo consultant and 

 helicopter pilot for film trials. We thank two anony- 

 mous reviewers for helpful comments on the manuscript. 



Literature cited 



Anonymous. 



1986. Report of the bluefin working group. Miami, Florida, 

 USA. September 1985. Int. Comm. Conserv. Atl. Tunas, 

 Coll. Vol. Sci. Pap., Madrid 24:11. 

 Clark, C. W., and M. Mangel. 



1978. Aggregation and fishery dynamics: a theoretical study 

 of schooling and the purse seine tuna fisheries. Fish. Bull. 

 77:317-329. 

 Clay, D. 



1991. Atlantic bluefin tuna (Thunnus thynnus) (L): a 

 review. In World meeting on stock assessment of bluefin 

 tunas: strengths and weaknesses. Inter-Am. Trop. Tuna 

 Commission Spec. Rep. 7, p. 91-179. 

 Laurs, R. M., P. C. Fiedler, and D. R. Montgomery. 



1984. Albacore tuna catch distributions relative to environ- 



mental features observed from satellite. Deep-Sea Res. 

 31:1085-1099. 



l.o., N. C. H., I. D. Jacobson, and J. L. Squire. 



1992. Indices of relative abundance from fish spotter data 

 based on delta-lognormal models. Can. J. Fish. Aquat. 

 Sci. 49:2515-2526. 



Mather, F. J., III. 



1962. Tunas (genus Thunnus) of the western North Atlan- 

 tic. Part III: Distribution and behavior of Thunnus 

 species. In Symposium on scombroid fishes, Part 1, p. 1- 

 16. Symp. Series 1, Marine Biological Association of In- 

 dia. Mandapam Camp., India, 564 p. 



Maul, G. A., F. Williams, M. Roffer, and F. Sousa. 



1984. Remotely sensed oceanographic patterns and vari- 

 ability of bluefin tuna catch in the Gulf of Mexico. 

 Oceanol. Acta 7:469-^179. 



Partridge, B. L., J. Johansson, and J. Kalish. 



1983. The structure of schools of giant bluefin tuna in Cape 

 Cod. Envir. Biol. Fishes 9:253-262. 



Petit, M., J-M. Stretta, H. Farrugio, and A. Wadsworth. 



1992. Synthetic aperture radar imaging of sea surface life 

 and fishing activities. IEEE Trans. Geosci. Rem. Sens. 

 80:1085-1089. 



Rivas, L. R. 



1978. Aerial surveys leading to 1974-1976 estimates of the 

 numbers of spawning giant bluefin tuna (Thunnus thynnus) 

 migrating past the western Bahamas. Int. Comm. 

 Conserv. Atlantic Tunas Coll. Vol. Sci., paper 7, p. 301-312. 



Roffer, M. A 



1987. Influence of the environment on the distribution and 

 relative apparent abundance of juvenile Atlantic bluefin 

 tuna along the United States east coast. Ph.D. diss., Univ. 

 Miami, Coral Gables, FL, 154 p. 



Safina, C. 



1993. Bluefin tuna in the West Atlantic: negligent manage- 

 ment and the making of an endangered species. Conserv. 

 Biol. 7:229-233 



Scott, G. P., M. R. Dewey, L. J. Hansen, R. E. Owen, 

 and E. S. Rutherford. 



1989. How many mullet are there in Florida Bay? Bull. 

 Mar. Sci. 44:89-107. 

 Scott, G. P., S. C. Turner, C. B. Grimes, W. J. Richards, 

 and E. B. Brothers. 



1993. Indices of larval bluefin tuna, Thunnus thynnus, 

 abundance in the Gulf of Mexico; modelling variability in 

 growth, mortality, and gear selectivity. Bull. Mar. Sci. 

 53:912-929. 

 Squire, J. L. 



1961. Aerial fish spotting in the United States commercial 

 fisheries. U.S. Fish. Wild! Serv., Commer. Fish. Rev. 23:1-7. 

 1972. Apparent abundance of some pelagic marine fishes 

 off the southern and central California coast as surveyed 

 by an airborne monitoring program. U.S. Fish. Wild]. 

 Serv. Fish. Bull. 70:1005-1019. 

 1993. Relative abundance of pelagic resources utilized by 

 the California purse-seine fishery: results of an airborne 

 monitoring program, 1962-90. Fish. Bull. 93:348-361. 

 Suzuki, Z., and Y. Ishizuka. 



1991. Comparison of population characteristics of world 

 bluefin stocks, with special reference to the West Atlantic 

 bluefin stock. Coll. Vol. Sci. Pap. ICCAT Reel. Doc. Vol. 

 35, No. 2., p. 240-245. 

 Williams, M. 



1981. Aerial survey of pelagic fish resources of South East 

 Australia 1973-1977. CSIRO Div. Fish. Oceanogr. Rep. 

 No. 130. 



