Catch Rates with Variable Strength Circle Hooks in the Hawaii-Based Tuna Longline Fishery

The Hawaii-based deep-set longline fleet targets bigeye tuna [Thunnus obesus (Lowe, 1839)] and infrequently takes false killer whales [FKW , Pseudorca crassidens (Owen, 1846)] as bycatch. From 2004 to 2008 with 20%–26% observer coverage, nine mortalities of and serious injuries to FKW were documented in the deep-set fishery in the Hawaii EE Z, yielding a mean take estimate of 7.3 animals yr−1. Weak hook technology can utilize the size disparity between target and other species to promote the release of larger non-target species. Four vessels tested the catch efficacy and size selectivity of 15/0 “strong” circle hooks (4.5 mm wire diameter) that straighten at 138 kg of pull in comparison with 15/0 “weak” (4.0 mm) that straighten at 93 kg of pull. Vessels alternated hook types throughout the longline gear and maintained a 1:1 ratio of strong and weak hooks. Observers monitored a total of 127 sets of 302,738 hooks, and randomization tests were applied to test for significant differences in catch for 22 species. There were no significant catch differences for bigeye tuna; however, there may be limitations to these inferences because trials were not conducted during spring when larger bigeye tuna are available to the fishery. There were no significant differences in mean length of 15 species. Observers collected 76 straightened hooks, of which six were control and 70 were weak hooks. There was one observation of a FKW released from a stronger circle hook. Overall, there was no statistical reduction in catch rates of bycatch species

Cluster analysis of longline sets and fishing strategies within the Hawaii-based fishery.

Abstract In the Hawaii-based longline fishery, changes in fishing operations to target different species produce changes in the effectiveness of fishing effort units. Catch-per-unit-effort (CPUE) indices used in resource monitoring were improved by segregating dissimilar types of fishing effort. Cluster analysis was used to classify longline sets in relation to species composition of the catches. Based on proportions of eight species and three broader species groups in 46 961 longline sets from 4 years (1991)(1992)(1993)(1994) of commercial fishery data, five effort clusters were identified. Spatial distribution of sets and differences in fishing operations among clusters were then compared to reveal apparent differences in fishing strategies. Three clusters comprised N 80% of the total sets, and the catch compositions suggested targeting for either broadbill swordfish (two clusters) or bigeye tuna. The other two clusters were most similar to the tuna cluster, but their catch compositions indicated a mixed-species fishing strategy. Fishing operations were most different between sets in the tuna and swordfish clusters. Swordfish sets were characterized by (1) the largest vessels, (2) the least number of hooks per set, (3) the greatest number of lightsticks, (4) the longest set duration, (5) the highest percentage of night sets, (6) a larger percentage of sets within the full moon phase, and (7) the lowest percentage of sets within the main Hawaiian Islands Exclusive Economic Zone. Time series of CPUE for three species (bigeye tuna, yellowfin tuna, and swordfish) based on different clusters were compared, and the most appropriate CPUE time series for resource monitoring are recommended. 0 1997 Elsevier Science B.V

The adaptive significance of cultural behavior

In this article, I argue that human social behavior is a product of the coevolution of human biology and culture. While critical of attempts by anthropologists to explain cultural practices as if they were independent of the ability of individual human beings to survive and reproduce, I am also leery of attempts by biologists to explain the consistencies between neo-Darwinian theory and cultural behavior as the result of natural selection for that behavior. Instead, I propose that both biological and cultural attributes of human beings result to a large degree from the selective retention of traits that enhance the inclusive fitnesses of individuals in their environments. Aspects of human biology and culture may be adaptive in the same sense despite differences between the mechanisms of selection and regardless of their relative importance in the evolution of a trait. The old idea that organic and cultural evolution are complementary can thus be used to provide new explanations for why people do what they do .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44491/1/10745_2005_Article_BF01531215.pd

Age and growth in paralarvae of the mesopelagic squid Abralia trigonura based on daily growth increments in statoliths

Growth increments in statoliths were used to estimate the age of 55 Abralia trigonura (Berry, 1913), a small tropical mesopelagic enoploteuthid squid collected from Hawaiian waters in 1988 and 1989. Growth increments were examined with light and scanning electron microscopy. Daily periodicity of increment formation and the statolith size at hatching were confirmed by rearing hatchlings in the laboratory. Mantle length (ML) at age data suggested that paralarvae grew exponentially at a rate of 5.9 % ML d-1 for ca 40 d post-hatching, while post-paralarvae exhibited slower growth. No significant difference in growth was noted between paralarvae collected from spatially or temporally separated samples, though estimated length differed at hatching. Estimated paralarval mortality was 7.0 % d-1. Within statolith microstructures, a transition in increment widths occurred at an average of 41.5 increments, which corresponded to 10.9 mm ML. The transition probably represents the end of the paralarval period, which is marked by a shift from an epipelagic to a mesopelagic habitat

National Oceanic and Atmospheric Administration Report 13

From abstract: This paper presents corrected catch histories, standardized catch rates, and evaluations of the accuracy of federally mandated commercial logbooks for billfishes taken as incidental catch by the Hawaii-based longline fishery. The study was conducted because billfish misidentifications in logbooks caused by similarities in body size, shape, and coloration have long represented a major challenge in monitoring this fishery