Evaluation of a video camera technique for indexing abundances of juvenile pink snapper, Pristipomoides filamentosus, and other Hawaiian insular shelf fishes

• Published in: Fishery bulletin (Washington, D.C.) Vol. 93; no. 1; pp. 67 - 77
• Main Authors: Ellis, D M, DeMartini, EE
• Format: Journal Article
• Language: English
• Published: 01.01.1995
• Subjects: Marine; Pisces; Pristipomoides filamentosus; ISE, USA, Hawaii
• ISSN: 0090-0656

Bottom longline and baited video camera operations were conducted at 39 stations off the Hawaiian Islands of Oahu, Maui, and Kauai during 1992. Objectives of the 1992 cruise were to assess the precision, accuracy, and efficiency of a video camera system versus a traditional abundance index (longline catch per unit of effort [CPUE]) for juvenile pink snapper ("opakapaka"), Pristipomoides filamentosus, a commercially important eteline snapper in Hawaii. Precision of the video samples was reevaluated with data from 18 stations sampled during 1993 off Kaneohe Bay. The video index of the maximum number of opakapaka observed (MAXNO, the natural log-transformed mean of three camera drops) was best correlated with the log of longline CPUE (r=0.79, P<0.001, n=15). Variation in the data for video MAXNO was nominally less than that of the longline CPUE. No monotone trend over stations was noted in samples from 1993. Sample sizes of 33 stations for longline and 18 stations for video would be necessary to detect twofold changes in abundance of opakapaka at a site, based on our analysis of the two end positions of the 10 windward Oahu stations that had three quantitative deployments. Reanalysis of power with data from the 1993 cruise indicates that a sample size of approximately 22 stations ( alpha sub(2)=0.05) or approximately 17 stations ( alpha sub(2)=0.1) would be necessary to detect twofold changes.